Chuyên đề:
BỆNH GIUN ĐŨA HEO
ASCARIASIS
(Large roundworm of pig)
BỆNH GIUN ĐŨA HEO
ASCARIASIS
(Large roundworm of pig)
Written by:
NGUYỄN HỮU HIỆP
Thú Y K08 A
Đại học Tây Nguyên
NGUYỄN HỮU HIỆP
Thú Y K08 A
Đại học Tây Nguyên
BACKGROUND
Our country is an agricultural country, so farming and husbandry are still the key branches in national strategy of economic development.
Animal husbandry which is on the increase in product not only diversity but also quality always is the major interest of society. Especially, the country integrated into the international market, people more attached special importance to the product quality. Food safety issues have highlighted in many meetings, set up a propaganda, diffused among the people as the urgency for the health of the community.
Our country is an agricultural country, so farming and husbandry are still the key branches in national strategy of economic development.
Animal husbandry which is on the increase in product not only diversity but also quality always is the major interest of society. Especially, the country integrated into the international market, people more attached special importance to the product quality. Food safety issues have highlighted in many meetings, set up a propaganda, diffused among the people as the urgency for the health of the community.
That is why branch of animal health has focused on research , proposed various measures to prevent damage from the poultry and cattle diseases, organized inoculations against an epidemic, disinfected , inspected at slaughter and quarantined animals for transportation.
The measures are launched, simultaneously, livestock is ensured , meat safety is cared as a first criterion, including standards for color and smell, criterion of chemical in meat, in by-product, the existence of parasitic worm in intestine.
For the pig husbandry, although the provision of meat for consumers has been attached special importance more and more, technical investment hasn’t been equal, especially lacking investment of technique in domestic husbandry and small farm . Pig is dwarfish(thin), has diarrhoea, meanwhile, expenses of investment have increased. One of the reasons identified as pig infected with species of helminth.
According to the survey of the Pasteur Institute at Chanh Hung slaughterhouse in SaiGon(1963), up to 70% of pigs infected with Ascaris suum , the head of the 12 helminth species were discovered, and according to latest report of Veterinary Station of Dien Khanh (2010)that survey of infection with parasite at slaughterhouse in district showed that had 21% of pigs infected Ascaris suum.
I work as a veterinay officer, often combine Preventive Medical Center of Dien Khanh district to go on inspection about food safety, I think it is necessary to find epidemiological characteristics of Ascariasis, infection rate, damage to economy and result of parasiticides using in the district, it is basic for proposing measures to protect animal health and providing consumers with safety sources of meat.
Chapter 1
OVERVIEW
1. Structural and morphological characterization of roundworm of pigs Ascaris suum.
Ascaris suum is a parasitic nematode that causes ascariasis in pigs (a parasitic worm in pig small intestine (mainly duodenum), milky white, cylindrical, slightly pointed ends. There are 3 lips surrounding the mouth, one lip is at the back, other two are at the abdomen. A serrated row is on the edge of lip. There is difference between Ascaris suum and Ascaris lumbricoides, serrated row of Ascaris lumbricoides is not as clear as serrated row of Ascaris suum.
Males are about 15–31 centimetres (6–12 inches) in length, and 2–4 millimetres (0.08–0.16 inches) in width. The posterior end curves toward the ventral side. They have simple spicules that measure 2.0–3.5 mm (0.08–0.14 inches) in length.
Females which are larger than males measure 20–49 cm (8–19 inches) by 3–6 mm (0.12–0.24 inches). From the anterior end, the vulva occupy about one-third in body length.
Eggs are slightly short and oval, size 0.056 to 0.087 x 0.046 to 0.067 mm, thick eggshell with 4 layer, but the outer layer of ascaris suum eggs is protein and heave. It is brownish-yellow by effect of bile fluid.
2. Life cycle of Ascaris suum:
Female worms may produce as many as 200.000 eggs daily during her lifetime in the definitive host which can be a year or more. One female worm may produce 27 million eggs in the lifetime.
Eggs which had just discharged with feces didn’t not cause disease. If pigs swallowed these eggs, they wouldn't be infected with Ascaris suum.. Eggs needed a few day to develop in the external environment. At the most proper conditions of temperature and humidity within 10 days, eggs matured. Their growth was slower at low temperatures [7].
The egestion of feces icluding the eggs which had embryos. Embryonated eggs continued development and depended on pressure of oxygen, humidity and ambient temperature. Eggs could live over 6 years in cold dry regions. At 22-33oC within 9-13 days, fertilized eggs developed into larvae which lay curled up inside. The first stage larvae I passed through 7 days to molt into infectious larvae in the egg, until it didn’t hatch until it penetrated into host (except for exceptions). Layer of egg-shell was described above, it showed that its strong resistances to many chemicals. Rearing in the laboratory, eggs developed into normal embryos in solution of formalin 2%. Eggs were killed by direct sunlight for a few weeks. Ascaris eggs developed normally in acetic acid and lactic acid 20%, however, strong picric acid could dissolve layer of chitin. Eggs were destroyed in NaOH 1% at 70 ° C for 15-20 minutes. Formalin 10% did not hatch the eggs and larvae were able to infect [2]
Pigs were infected with Ascaris suum eggs through food and water, but most sources of infection were the cage. Earthworms have been infected with Ascaris eggs that had larva supposing sources of pregnant with pathogens. The sticky nipple of pigs covered in ascaris eggs. Piglet had been infected while they were sucking. There were not infected cases ofAscaris suum before laying like infected cases of other Ascaris.
Ascaris suum eggs entered the gut , some factors in the intestine (special about the pressure of CO2) influenced hatch. CO2 could penetrate more quickly through cell membranes. Most eggs hatched in the duodenum but some in the stomach. For Fairbarn (1961), Jaskoski, Colucci (1964), Rogers (1960) after stimulus of hatch, the hatch fluid consisted of at least two chitinase and esterase enzymes was secreted. Effect of the enzymes on chitin sheath and the lipid of membrane, and even enzyme of proteins was chance for larvae to get out. Rogers and Sommerville (1968) speculated that effect of CO2 on receptors stimulated neurosecretion, secreted enzymes for participating in the process of hatch. Larvae were got out or was in period 2 ( already developed once in eggs) or was still at sheath of the first stage. The phenomenon of haemorrhage mucous membrane of the duodenum and jejunum appeared during 2 hours before larvae entered the venous system of liver.
Larvae were in the liver for several days, then it molted into Larvae 3. Leaving the liver, Larvae were in the process of moving blood to the heart, through the pulmonary artery into the lungs, they stayed at lung for 4-7 days, Larvae broke the capillaries, then into alveolus where they molted to the fourth stage larvae form. The Fourth Larvae moved to the bronchi, the windpipe(trachea) and then to the throat. The fourth stage larvae were swallowed back the gut, they grew rapidly and molted to the fifth stage larvae. Developmental cycle of Ascaris suum in pigs was 40-53 days (Galvin 1968). The lifetime of the worm was 6 months to over one year [2].
In blood, a few larvae in the process of moving can stop in the pulmonary capillaries, through the pulmonary veins to the left of the heart, from that, larvae which could follow the circulation of aorta to come to different tissues and organs of animals. To pregnant animals, the larvae thus moved could enter the fetus by blood circulation [7].
Roundworm lived on host’s nutrient, and secreted digestive juice to resolve organ of the mucous membrane of gut for their living.. The lifespan of the roundworm was not over 7-10 months, after that the roundworm were eliminated with feces. If condition was disadvantage for roundworm(animals with infectious diseases, high fever ...), their lifespan was shorter. Roundworms parasitize in pigs 3-4 months on average. The number of worms in one pig is from some to over a thousand.
Adult worms didn’t need any intermediate hosts, pigs swallowed directly ingestion of roundworm eggs causes, then develop into adult worms.
According to Phan Lu and Nguyen Duc Tam (2000) [3], surveyed on development of larvae Ascaris suum in earthworm Perionyx excavatus surrounding pigsty in the outskirts of Hanoi found out 18.2% earthworms infected with larvae of Ascaris suum at intensity 1-3 larvae per earthworm, while only 1.8% of earthworm infected with larvae of Metastrongylus sp at intensity 1-2 larvae per earthworm. Moreover larval Ascaris suum in earthworms had survived and grown in size for a long time. Although earthworms were not intermediate hosts, they were very condition for larvae of earthworm to survive and develop. They waited for the opportunity to enter and harm swine.
3. Epidemiological characteristics of ascariasis in pig:
The presence of roundworms are over the world, the main condition is supposed is simple life cycle of Ascaris suum, direct transmission and very high resistance of the eggs.
Characteristics of Ascaris suum egg are four layers of eggshell: the innermost layer protects the embryo and keep the organic substance not to affect eggs, two middle layer of the egg keep the fluid not to evaporate, the outer layer is a brown yellow protein layer prevents ultraviolet rays from penetrating into the interior. Eggs live about 6-12 months in heap of feces, live about 1-2 years in natural conditions. Appropriate temperature for egg’s development is around 25oC. When lower temperature (12oC) eggs develop slowly.
At 3 cm in-depth, temperature about 26 - 33oC, water content 9.5 to 19% , 89% of the eggs develop. The eggs stop developing at very low temperatures: - 4.8 ° C to - 13.4 ° C, water content 6.3 to 17%. Eggs can be killed because of one of the three following cases:
-Humidity is too low
-Low humidity, high temperature.
-High temperature and humidity.
Eggs are killed at 45-50oC for a half an hour, in water 60°C for 5 minutes, water 70°C just 1-10 seconds. Rotting manure fecal matter, that is how to raise the temperature to kill all eggs of Ascaris suum. It is the first time Masnicova(1940)[5] has used gas heating (170oC) to kill eggs in pigsty and feces. When spraying on wet or dry feces, eggs are killed within 10-30 seconds. Ascaris suum eggs also have strong resistance to some chemicals such as: formaldehyde 2%, egg is alive and continues to grow, ereolin 3%, saturated solution of copper sulfate, sulfuric acid 10%, NaOH 2%, hypochlorite calcium 10% do not kill eggs. In summer, when sandy and ground flooded with direct sunlight, eggs are killed quickly Oxygen is necessary for egg to develop in anaerobic environments, the eggs can not develop, but still keep up life, so the eggs remain viable in dirty water and lack of oxigen environment for a short time.
+Details of infection process: roundworm eggs in food are swallowed, mainly through the mouth. Pigs like to lick, chew instruments such as feeding troughs, pasture... so it is very easy for eggs enter the digestive tract. Eggs in pig feces without rotting to manure a field growing food live several months.. Flies and mice, can also scatter eggs, eggs and dust are swept away by wind from pigsty to pigsty. Piglets infected mainly when sticking, swallow eggs at teat. A document showed larvae of Ascaris lumbricoids can penetrate through human skin at 34oC to cause disease.
+ The relationship between Ascaris lumbricoids and Ascaris suum. Ascarisroundworms in pigs: biologically, especially cross-infection, There has been an argument in recent years that they were two different types or the same species.
In general, artificial infection showed that man could be contaminated byAscaris suum and pig could be contaminated by Ascaris lumbricoids. Hiraishi (1928), Boer (1935) [6] had infected the pigs with Ascaris lumbricoids when they ate food which was lacking in vitamin. Soulsby (1961) [6] also infected newborn pigs which were not fed with Ascaris lumbricoids.
Takate (1951) infected 19 adult people with Ascaris suum eggs, result of experiment was seven people infected. Research of Mozgovoi (1953) showed that hosts of Ascaris lumbricoids were not only man but also up to 10 other animals such as pigs, dogs .... So the author admitted that roundworm of pig and roundworm of human were not the same species. . In terms of epidemiology, in an area found infected rate with Ascaris in pig was higher than in human, or in other area, infection rate with Ascaris in human was higher; It showed that they were not the same species and not to have directly relative.
Nguyen Phuoc Tuong, Da Nang Veterinary Association (1999) [6] in the article about The parasitic diseases of pigs to humans, showed that antigenic and chemical, morphological characterization of roundworm of pigs Ascaris suum were similar Ascaris lumbricoids. They had the same cycle of develoment by type of in the intestine-lung-trachea-gut .
That is why the parasitic roundworm Ascaris suum can transmit to human but this transmission is rare. However, ascarisis which caused by the larvae of Ascaris suum for human was rather common, then increased allergic reactions and Loeffler syndrome.
People who are depression (malnutrition, deficiency of immunity) are easy to catch roundworms of pig by swallowing Ascaris suum eggs from soil and vegetation.
When eggs were ingested, the second larvae were released in the intestinal, migrated to lung, trachea, then went up the esophagus and were swallowed back into the gut the second times in the fourth larvae. The roundworms which have origin from pig grew up in human bowel not to completely mature, eggs which are laid by female roundworm don’t have vital force , except acceptance of the human body is not normal.
Although some parasitologists believe that there is but one species ofAscaris that infects both pigs and humans, other scientist shows that life cycle of Ascaris suum is identical to that of A. lumbricoides. If a human ingested eggs of Ascaris suum, the larvae would migrate to the lungs and die. This can cause a particularly serious form of "ascaris pneumonia." Adult worms of this species do not develop in the human's intestine [8]
4. The infectious intensity and rate:
The infectious rate is from 13 to 14 % in the north(Phạm Văn Khuê, Trịnh Văn Thịnh, 1982) [4]. In 1978, Phạm Văn Khuê, Phan Văn Lục took an examination in 6 southern provinces, said that infectious rate of Ascaris suum was 31,04 %, among 1055 pigs surveyed, 40% were infected byAscaris suum in 3 eastern provines, 23 % were infected in the three provinces of Mekong Delta. In 1995, Luong Van Huan took an examination at autopsy 891 pigs of 4 age groups and surveyed 5044 adult pigs of 12 southern provinces showed that infectious rate was 53 %, Binh Tri Thien was 34 %, Quang Nam Da Nang was 61 %, Binh Dinh was 45 %, Phu Yen and Khanh Hoa were 75%, Dong Nai was 64 %, Song Be was 51%, Tay Ninh was 45 %, Ho Chi Minh City was 41 %, Tien Giang was 73 %, Kien Giang was 70%. Pham Van Chuc, Chau Ba Loc and colleagues (1986) reported that pigs were infected was 28-50% in Hau Giang. Bui Lap, Nguyen Dang Khai, Vu Sy Nhan (1979) reported that Central pigs were infected Central from 36 to 58 %.
Trinh van Thinh, Pham Van Khue, 1982 showed that:
- Infectious rate of pigs which was under 3 months old: 39,2 %
- Infectious rate of pigs which was 3 months old: 48 %
- Infectious rate of pigs which was from 5 to 7 months old: 58,3 %
- Infectious rate of pigs which was over 7 months old: 24,9 %
Luong Van Huan, Le Huu Khuong, 1995 showed that:
- Infectious rate of pigs which was under 3 months old: 49,8 %
- Infectious rate of pigs which was from 3 to 4 months old: 67,1 %
- Infectious rate of pigs which was from 5 to 7 months old: 62,6 % %
- Infectious rate of pigs which was over 7 months old: 40,6%.
5.Mechanism of pathogenesis :
Both larvae or adult roundworm are still pathogenous. Larvae at the gut penetrate to the wall of intestine, harm the gut. From here, bacteria penetrate to organism. When coming to lung, larvae makes disease of Swine enzootie pneumoniea worse, and the rate of pathogenesis can be increased 10 times.. For Underdahl (1957) lung of the pig infected with roundworm and disease of Swine Enzootie pneumoniea more serious than 10 times for pig only infected with disease of Swine Enzootie pneumoniea. When larvae in blood are transmitted to liver, they cause destruction of live cells, and cause haemorrhage with spotting symbol at the same times. Larvae migrate from blood vessel of lung to vesicule, so blood veesel is broken, lung has spots as well. When larvae which migrate to lung cause inflammation, this symptom depends on inflamed level, it is possible to last from 5 to 14 days, pigs can die. Deficiency in Vitamin A, it is very easy for pigs infected with lung disease because of harmful effect of roundworm. Larvae migrate for about 2- 3 weeks, and reduce gradually inflammation, Adult roundworm at small intestine cause stomach and mucous membrane ulcer, sometimes obstruction of the bowel, intestinal perforation. Roundworms which enter bile duct cause jaundice. They also secrete toxin which have a poisonous effect on blood vessel and the central nervous, neurological symptoms such as paralysis, or excitement.In addition, waste matter eliminated in the metabolic process causes stuntedness and retardation.
6. Damage from pig roundworm disease:
The migration of the larvae through the lungs causes the blood vessels of the lungs to hemorrhage and pneumonia. L2 larvae and and L3 larvae cause necrosis and hemorrhage at liver with size of about 1cm, and have a lot of fibrin. Larvae also cause injury to and tear the capillaries, this leads to graver symptoms of Swine Enzootie pneumonia. Concurrently, larvae carry E. coli into the blood.
Adult worms which are parasitical in the intestine cause intestinal ulcers and inflammation. Pigs growth slowly, are stunted by occupation nutrients from intestinal roundworms in the metabolic process. Roundworms cause obstruction of the bowels and intestinal perforation. Worms use a lot of Ca2 + which is necessary for pigs, softening of the bones, stunt and convulsion of pigs caused by deficiency of Ca. The bile duct was broken by worms’ migration to it.
7. Pathological characteristics and Clinical symptoms of pig roundworm disease:
7.1 Clinical symptoms:
Symptoms of adult pigs is unknown. Most pigs are infected with roundworm, they become source of spreading germ. Severe disease is seen at pigs from 3 to 6 months, pigs are skinny and grow slowly, larvae enter the lung, which causes pneumonia, rises pigs’ temperature, pigs breath hard and do not crave for food, appearance signs of pneumonia, adult worms is unknown symptoms: slow growth, thin, loss of weight, digestive disorder; a number of roundworms cause intestinal perforation and obstruction, stomach-ache, peritonitis, some pigs which are allergic with roundworm appear neurological symptoms, rash, cough ...
7.2 Pathological characteristics:
At first lung was inflammation, the surface of the lung has masses of dark pink blood. Cutting lung, people see plenty of larvae. Adult worms which parasitize in the small intestine slightly inflame mucous layer with appearance of mucus. Haemorrhage and peritonitis appear as a result of the perforation the gut.
8 .Diagnosis:
+ Pigs under 2 months of age: Although piglets have roundworms in the gut, roundworms have not laid eggs yet ( only lay from 54 to 62 days after migration and development in pig). Autopsy for diagnosis is necessary in search of larva at liver and lung.
+ Pigs over 2 moths of age:
How to find the eggs: The examination of fecal samples by method of Fulleborn.
Otherwise, people can make an autopsy to find in the small intestine.
+ Diagnosis by intradermal/intradermical injection: There are many ways to produce antigen for giving an injection into the skin, normally we use the method of Ecsop: cleaning roundworms alive with water, we crush them, then mix 2 parts of water, add 10 ml chloroform and 8 g enzyme of pancreas to every 1 ml of above mixture, adjust pH = 7,6-7,8. Having kept warm this solution for 7-12 days, the whole roundworms dissolved will be centrifugal, pour this solution into phial in which has alcohol 90 o, ratio 1:5, when antigen lie, take this antigen at the bottom of the vial, then continue to keep warm. It’s possible to keep up dry antigen in the refrigerator for over 8 months without influence on the antigen properties. This antigen will be diluted for test with ratio of 1:200. It is able to stick in the outer circle of ear or drop to eye-conjunctiva.
Diagnose methods are very good, no cross reaction in pigs infected withTrichocephalus suis, Oesophagostomum and Macracanthorhynchus hirudinaceus. Having been infected Ascaris suum from the eighth day to the eleventh day, pigs begin with a positive reaction. This reaction maintains between 110-140 days. After infection, metamorphosis response and concentration of antibody which appear at the same time and depend on adult worm in the intestine.
+ Do Duong Thai (1969) prepared antigen: Dead roundworms are mixed with physiological solution containing 5/1000 phenic acid. Le Ngoc My (1970) used this antigen. Its result is 65-80 % compared to examination of feces.
9. Treatment and prevention:
9.1 Prevention:
Pigsite is always clean, feeding trough and tool for livestock have been periodically disinfected. The best thing to do is disinfection feeding trough and tool every 10 days by boiling water. Rotting manure fecal matter will kill eggs, prevent from the spread of Ascaris suum.
Eggs are also destroyed by the physico-chemical methods Bredding farms which have lots of infected pigs with roundworm should be periodically disinfect, at least once a quarter, at the floor with boiling quarter. In cold seasons, the process of eliminating parasite from pigsty or surroundings by daily good sweep.
-The use of one of parasiticide for the weaned young pig and pig in 3-4 of age. If it is necessary we can use parasiticede for pig from 5-7 months old. Infectious rate of adult pigs which is lower, spreading roundworm showed that adult pigs are source of disease, so using parasiticede to kill roundworm in the pig-gut is encouraged.
-Pregnant sows: Use piperazin 200-300 mg/kg body weigh before producing.
-Raise resistance of pig by providing enough food, both quantity and quality, drinking-water is not pollution, examine health of pigs before taking pigs to farm.
Vaccine against Ascaris suum:
Ascariosis is traditionally being controlled by mass therapy with anthelmintics. Despite the high efficacy of these products, the long term effect of the anthelmintics is disappointing and the problem with ascariosis is actually increasing. The most important reason for this is the high fecundity of Ascaris suum (a female worm can produce up to 800.000 eggs/day) which causes a highly contaminated environment and the short activity of the anthelmintics. Only vaccination could result in a long-term, efficient control.
There were many tests in vaccination trials in the world. In Vietnam, a scientific test in preparing and using vaccine against Ascaris suum with embryo of roundworm eggs, and the effect of radioactive ray (1000r), the number of eggs is 500-1000 in a dose of vaccine. Safe vaccine; larvae which went through lung did not damage a lot, and they could not become adult roundworm in the gut. The rate of worm infection in pigs, are protected by the vaccine reduced 4.7 times compared with the infection in control pigs, the immune period is about 4 months.
.9.2 Treatment:
Pigs were infected with roundworm, use one of the following drugs:
- Tetramisole (Nilverm or Ascaridin): 20g / kg of body weigh, mixed with food or drink once.
-Levamisole (Vinacor, Decaris): 7.5% in aqueous solution
Intramuscular injection 6-8 mg / kg of body weigh for pigs which are less than 30 kg, 5-6 mg/kh of body weigh for pigs which are above 30 kg.
-Tetravermex: 10% powder, the dose of 20 mg / kg of body weigh for eating or drinking.
- Themisole: 15% , 200 ml/ bottle. Intramuscular injection dose of 1 ml / 20 kg of body weigh, not more than 5 ml / pig
- Nilverm: Produced in Australia , 7.5% concentration , 500 ml /bottle, 7-8 kh of body weigh.
- Nichlozamide-Tetramisole B: 5 g, 1 tablet for 75 kg of body weigh.
- Piperazine: only use (eating or drinking)Hexahydrate piperazine and mineral salt such as Adipinat, phosphate, sulfate. 0,3 g/kg of body weigh for pigs which are less than 50 kg in weight, and 15 g/kg of body weigh for pigs which are over 50 kg twice a day.
- Mebendazole (Mebenvet): 20 mg / kg of body weigh by eating or drinking. After using, pigs can be mild diarrhea.
- Dichlovos (DDVP): 0.2 g / kg P by eating or drinking.
- Benacine: 150 mg / kg of body weigh by eating or drinking.
- Phenothiazine: 0,5 g / kg of body weigh by eating or drinking. Phan Dich Lan (1962) proposal for two consecutive mornings, resulting in a 70-100% worms.
- Ivermectin: 0.1 to 0.3 mg / kg of body weigh injected intramuscularly or subcutaneously. According to Luc Phan, Nguyen Duc Tam (2000)[3], the drug proved effectively against adult worms form and the fourth-stage larvae
- Doramectin: 0.1 to 0.3 mg / kg of body weigh injected intramuscularly or subcutaneously.
- Also can use: Safersan, Morantel, benzimidazole, Febantel, Panacur, Parbendazole, Rintal, ...
- Leucaena leucocephala seeds: Dry, roast, grind. 60-100 g / pig. Mix with bran, dose depend on age Use continuously for 3 days.
- Old areca nut: 5-20 g/pig, boil then mix with good food. Feed pig.
The measures are launched, simultaneously, livestock is ensured , meat safety is cared as a first criterion, including standards for color and smell, criterion of chemical in meat, in by-product, the existence of parasitic worm in intestine.
For the pig husbandry, although the provision of meat for consumers has been attached special importance more and more, technical investment hasn’t been equal, especially lacking investment of technique in domestic husbandry and small farm . Pig is dwarfish(thin), has diarrhoea, meanwhile, expenses of investment have increased. One of the reasons identified as pig infected with species of helminth.
According to the survey of the Pasteur Institute at Chanh Hung slaughterhouse in SaiGon(1963), up to 70% of pigs infected with Ascaris suum , the head of the 12 helminth species were discovered, and according to latest report of Veterinary Station of Dien Khanh (2010)that survey of infection with parasite at slaughterhouse in district showed that had 21% of pigs infected Ascaris suum.
I work as a veterinay officer, often combine Preventive Medical Center of Dien Khanh district to go on inspection about food safety, I think it is necessary to find epidemiological characteristics of Ascariasis, infection rate, damage to economy and result of parasiticides using in the district, it is basic for proposing measures to protect animal health and providing consumers with safety sources of meat.
Chapter 1
OVERVIEW
1. Structural and morphological characterization of roundworm of pigs Ascaris suum.
Ascaris suum is a parasitic nematode that causes ascariasis in pigs (a parasitic worm in pig small intestine (mainly duodenum), milky white, cylindrical, slightly pointed ends. There are 3 lips surrounding the mouth, one lip is at the back, other two are at the abdomen. A serrated row is on the edge of lip. There is difference between Ascaris suum and Ascaris lumbricoides, serrated row of Ascaris lumbricoides is not as clear as serrated row of Ascaris suum.
Males are about 15–31 centimetres (6–12 inches) in length, and 2–4 millimetres (0.08–0.16 inches) in width. The posterior end curves toward the ventral side. They have simple spicules that measure 2.0–3.5 mm (0.08–0.14 inches) in length.
Females which are larger than males measure 20–49 cm (8–19 inches) by 3–6 mm (0.12–0.24 inches). From the anterior end, the vulva occupy about one-third in body length.
Eggs are slightly short and oval, size 0.056 to 0.087 x 0.046 to 0.067 mm, thick eggshell with 4 layer, but the outer layer of ascaris suum eggs is protein and heave. It is brownish-yellow by effect of bile fluid.
2. Life cycle of Ascaris suum:
Female worms may produce as many as 200.000 eggs daily during her lifetime in the definitive host which can be a year or more. One female worm may produce 27 million eggs in the lifetime.
Eggs which had just discharged with feces didn’t not cause disease. If pigs swallowed these eggs, they wouldn't be infected with Ascaris suum.. Eggs needed a few day to develop in the external environment. At the most proper conditions of temperature and humidity within 10 days, eggs matured. Their growth was slower at low temperatures [7].
The egestion of feces icluding the eggs which had embryos. Embryonated eggs continued development and depended on pressure of oxygen, humidity and ambient temperature. Eggs could live over 6 years in cold dry regions. At 22-33oC within 9-13 days, fertilized eggs developed into larvae which lay curled up inside. The first stage larvae I passed through 7 days to molt into infectious larvae in the egg, until it didn’t hatch until it penetrated into host (except for exceptions). Layer of egg-shell was described above, it showed that its strong resistances to many chemicals. Rearing in the laboratory, eggs developed into normal embryos in solution of formalin 2%. Eggs were killed by direct sunlight for a few weeks. Ascaris eggs developed normally in acetic acid and lactic acid 20%, however, strong picric acid could dissolve layer of chitin. Eggs were destroyed in NaOH 1% at 70 ° C for 15-20 minutes. Formalin 10% did not hatch the eggs and larvae were able to infect [2]
Pigs were infected with Ascaris suum eggs through food and water, but most sources of infection were the cage. Earthworms have been infected with Ascaris eggs that had larva supposing sources of pregnant with pathogens. The sticky nipple of pigs covered in ascaris eggs. Piglet had been infected while they were sucking. There were not infected cases ofAscaris suum before laying like infected cases of other Ascaris.
Ascaris suum eggs entered the gut , some factors in the intestine (special about the pressure of CO2) influenced hatch. CO2 could penetrate more quickly through cell membranes. Most eggs hatched in the duodenum but some in the stomach. For Fairbarn (1961), Jaskoski, Colucci (1964), Rogers (1960) after stimulus of hatch, the hatch fluid consisted of at least two chitinase and esterase enzymes was secreted. Effect of the enzymes on chitin sheath and the lipid of membrane, and even enzyme of proteins was chance for larvae to get out. Rogers and Sommerville (1968) speculated that effect of CO2 on receptors stimulated neurosecretion, secreted enzymes for participating in the process of hatch. Larvae were got out or was in period 2 ( already developed once in eggs) or was still at sheath of the first stage. The phenomenon of haemorrhage mucous membrane of the duodenum and jejunum appeared during 2 hours before larvae entered the venous system of liver.
Larvae were in the liver for several days, then it molted into Larvae 3. Leaving the liver, Larvae were in the process of moving blood to the heart, through the pulmonary artery into the lungs, they stayed at lung for 4-7 days, Larvae broke the capillaries, then into alveolus where they molted to the fourth stage larvae form. The Fourth Larvae moved to the bronchi, the windpipe(trachea) and then to the throat. The fourth stage larvae were swallowed back the gut, they grew rapidly and molted to the fifth stage larvae. Developmental cycle of Ascaris suum in pigs was 40-53 days (Galvin 1968). The lifetime of the worm was 6 months to over one year [2].
In blood, a few larvae in the process of moving can stop in the pulmonary capillaries, through the pulmonary veins to the left of the heart, from that, larvae which could follow the circulation of aorta to come to different tissues and organs of animals. To pregnant animals, the larvae thus moved could enter the fetus by blood circulation [7].
Roundworm lived on host’s nutrient, and secreted digestive juice to resolve organ of the mucous membrane of gut for their living.. The lifespan of the roundworm was not over 7-10 months, after that the roundworm were eliminated with feces. If condition was disadvantage for roundworm(animals with infectious diseases, high fever ...), their lifespan was shorter. Roundworms parasitize in pigs 3-4 months on average. The number of worms in one pig is from some to over a thousand.
Adult worms didn’t need any intermediate hosts, pigs swallowed directly ingestion of roundworm eggs causes, then develop into adult worms.
According to Phan Lu and Nguyen Duc Tam (2000) [3], surveyed on development of larvae Ascaris suum in earthworm Perionyx excavatus surrounding pigsty in the outskirts of Hanoi found out 18.2% earthworms infected with larvae of Ascaris suum at intensity 1-3 larvae per earthworm, while only 1.8% of earthworm infected with larvae of Metastrongylus sp at intensity 1-2 larvae per earthworm. Moreover larval Ascaris suum in earthworms had survived and grown in size for a long time. Although earthworms were not intermediate hosts, they were very condition for larvae of earthworm to survive and develop. They waited for the opportunity to enter and harm swine.
3. Epidemiological characteristics of ascariasis in pig:
The presence of roundworms are over the world, the main condition is supposed is simple life cycle of Ascaris suum, direct transmission and very high resistance of the eggs.
Characteristics of Ascaris suum egg are four layers of eggshell: the innermost layer protects the embryo and keep the organic substance not to affect eggs, two middle layer of the egg keep the fluid not to evaporate, the outer layer is a brown yellow protein layer prevents ultraviolet rays from penetrating into the interior. Eggs live about 6-12 months in heap of feces, live about 1-2 years in natural conditions. Appropriate temperature for egg’s development is around 25oC. When lower temperature (12oC) eggs develop slowly.
At 3 cm in-depth, temperature about 26 - 33oC, water content 9.5 to 19% , 89% of the eggs develop. The eggs stop developing at very low temperatures: - 4.8 ° C to - 13.4 ° C, water content 6.3 to 17%. Eggs can be killed because of one of the three following cases:
-Humidity is too low
-Low humidity, high temperature.
-High temperature and humidity.
Eggs are killed at 45-50oC for a half an hour, in water 60°C for 5 minutes, water 70°C just 1-10 seconds. Rotting manure fecal matter, that is how to raise the temperature to kill all eggs of Ascaris suum. It is the first time Masnicova(1940)[5] has used gas heating (170oC) to kill eggs in pigsty and feces. When spraying on wet or dry feces, eggs are killed within 10-30 seconds. Ascaris suum eggs also have strong resistance to some chemicals such as: formaldehyde 2%, egg is alive and continues to grow, ereolin 3%, saturated solution of copper sulfate, sulfuric acid 10%, NaOH 2%, hypochlorite calcium 10% do not kill eggs. In summer, when sandy and ground flooded with direct sunlight, eggs are killed quickly Oxygen is necessary for egg to develop in anaerobic environments, the eggs can not develop, but still keep up life, so the eggs remain viable in dirty water and lack of oxigen environment for a short time.
+Details of infection process: roundworm eggs in food are swallowed, mainly through the mouth. Pigs like to lick, chew instruments such as feeding troughs, pasture... so it is very easy for eggs enter the digestive tract. Eggs in pig feces without rotting to manure a field growing food live several months.. Flies and mice, can also scatter eggs, eggs and dust are swept away by wind from pigsty to pigsty. Piglets infected mainly when sticking, swallow eggs at teat. A document showed larvae of Ascaris lumbricoids can penetrate through human skin at 34oC to cause disease.
+ The relationship between Ascaris lumbricoids and Ascaris suum. Ascarisroundworms in pigs: biologically, especially cross-infection, There has been an argument in recent years that they were two different types or the same species.
In general, artificial infection showed that man could be contaminated byAscaris suum and pig could be contaminated by Ascaris lumbricoids. Hiraishi (1928), Boer (1935) [6] had infected the pigs with Ascaris lumbricoids when they ate food which was lacking in vitamin. Soulsby (1961) [6] also infected newborn pigs which were not fed with Ascaris lumbricoids.
Takate (1951) infected 19 adult people with Ascaris suum eggs, result of experiment was seven people infected. Research of Mozgovoi (1953) showed that hosts of Ascaris lumbricoids were not only man but also up to 10 other animals such as pigs, dogs .... So the author admitted that roundworm of pig and roundworm of human were not the same species. . In terms of epidemiology, in an area found infected rate with Ascaris in pig was higher than in human, or in other area, infection rate with Ascaris in human was higher; It showed that they were not the same species and not to have directly relative.
Nguyen Phuoc Tuong, Da Nang Veterinary Association (1999) [6] in the article about The parasitic diseases of pigs to humans, showed that antigenic and chemical, morphological characterization of roundworm of pigs Ascaris suum were similar Ascaris lumbricoids. They had the same cycle of develoment by type of in the intestine-lung-trachea-gut .
That is why the parasitic roundworm Ascaris suum can transmit to human but this transmission is rare. However, ascarisis which caused by the larvae of Ascaris suum for human was rather common, then increased allergic reactions and Loeffler syndrome.
People who are depression (malnutrition, deficiency of immunity) are easy to catch roundworms of pig by swallowing Ascaris suum eggs from soil and vegetation.
When eggs were ingested, the second larvae were released in the intestinal, migrated to lung, trachea, then went up the esophagus and were swallowed back into the gut the second times in the fourth larvae. The roundworms which have origin from pig grew up in human bowel not to completely mature, eggs which are laid by female roundworm don’t have vital force , except acceptance of the human body is not normal.
Although some parasitologists believe that there is but one species ofAscaris that infects both pigs and humans, other scientist shows that life cycle of Ascaris suum is identical to that of A. lumbricoides. If a human ingested eggs of Ascaris suum, the larvae would migrate to the lungs and die. This can cause a particularly serious form of "ascaris pneumonia." Adult worms of this species do not develop in the human's intestine [8]
4. The infectious intensity and rate:
The infectious rate is from 13 to 14 % in the north(Phạm Văn Khuê, Trịnh Văn Thịnh, 1982) [4]. In 1978, Phạm Văn Khuê, Phan Văn Lục took an examination in 6 southern provinces, said that infectious rate of Ascaris suum was 31,04 %, among 1055 pigs surveyed, 40% were infected byAscaris suum in 3 eastern provines, 23 % were infected in the three provinces of Mekong Delta. In 1995, Luong Van Huan took an examination at autopsy 891 pigs of 4 age groups and surveyed 5044 adult pigs of 12 southern provinces showed that infectious rate was 53 %, Binh Tri Thien was 34 %, Quang Nam Da Nang was 61 %, Binh Dinh was 45 %, Phu Yen and Khanh Hoa were 75%, Dong Nai was 64 %, Song Be was 51%, Tay Ninh was 45 %, Ho Chi Minh City was 41 %, Tien Giang was 73 %, Kien Giang was 70%. Pham Van Chuc, Chau Ba Loc and colleagues (1986) reported that pigs were infected was 28-50% in Hau Giang. Bui Lap, Nguyen Dang Khai, Vu Sy Nhan (1979) reported that Central pigs were infected Central from 36 to 58 %.
Trinh van Thinh, Pham Van Khue, 1982 showed that:
- Infectious rate of pigs which was under 3 months old: 39,2 %
- Infectious rate of pigs which was 3 months old: 48 %
- Infectious rate of pigs which was from 5 to 7 months old: 58,3 %
- Infectious rate of pigs which was over 7 months old: 24,9 %
Luong Van Huan, Le Huu Khuong, 1995 showed that:
- Infectious rate of pigs which was under 3 months old: 49,8 %
- Infectious rate of pigs which was from 3 to 4 months old: 67,1 %
- Infectious rate of pigs which was from 5 to 7 months old: 62,6 % %
- Infectious rate of pigs which was over 7 months old: 40,6%.
5.Mechanism of pathogenesis :
Both larvae or adult roundworm are still pathogenous. Larvae at the gut penetrate to the wall of intestine, harm the gut. From here, bacteria penetrate to organism. When coming to lung, larvae makes disease of Swine enzootie pneumoniea worse, and the rate of pathogenesis can be increased 10 times.. For Underdahl (1957) lung of the pig infected with roundworm and disease of Swine Enzootie pneumoniea more serious than 10 times for pig only infected with disease of Swine Enzootie pneumoniea. When larvae in blood are transmitted to liver, they cause destruction of live cells, and cause haemorrhage with spotting symbol at the same times. Larvae migrate from blood vessel of lung to vesicule, so blood veesel is broken, lung has spots as well. When larvae which migrate to lung cause inflammation, this symptom depends on inflamed level, it is possible to last from 5 to 14 days, pigs can die. Deficiency in Vitamin A, it is very easy for pigs infected with lung disease because of harmful effect of roundworm. Larvae migrate for about 2- 3 weeks, and reduce gradually inflammation, Adult roundworm at small intestine cause stomach and mucous membrane ulcer, sometimes obstruction of the bowel, intestinal perforation. Roundworms which enter bile duct cause jaundice. They also secrete toxin which have a poisonous effect on blood vessel and the central nervous, neurological symptoms such as paralysis, or excitement.In addition, waste matter eliminated in the metabolic process causes stuntedness and retardation.
6. Damage from pig roundworm disease:
The migration of the larvae through the lungs causes the blood vessels of the lungs to hemorrhage and pneumonia. L2 larvae and and L3 larvae cause necrosis and hemorrhage at liver with size of about 1cm, and have a lot of fibrin. Larvae also cause injury to and tear the capillaries, this leads to graver symptoms of Swine Enzootie pneumonia. Concurrently, larvae carry E. coli into the blood.
Adult worms which are parasitical in the intestine cause intestinal ulcers and inflammation. Pigs growth slowly, are stunted by occupation nutrients from intestinal roundworms in the metabolic process. Roundworms cause obstruction of the bowels and intestinal perforation. Worms use a lot of Ca2 + which is necessary for pigs, softening of the bones, stunt and convulsion of pigs caused by deficiency of Ca. The bile duct was broken by worms’ migration to it.
7. Pathological characteristics and Clinical symptoms of pig roundworm disease:
7.1 Clinical symptoms:
Symptoms of adult pigs is unknown. Most pigs are infected with roundworm, they become source of spreading germ. Severe disease is seen at pigs from 3 to 6 months, pigs are skinny and grow slowly, larvae enter the lung, which causes pneumonia, rises pigs’ temperature, pigs breath hard and do not crave for food, appearance signs of pneumonia, adult worms is unknown symptoms: slow growth, thin, loss of weight, digestive disorder; a number of roundworms cause intestinal perforation and obstruction, stomach-ache, peritonitis, some pigs which are allergic with roundworm appear neurological symptoms, rash, cough ...
7.2 Pathological characteristics:
At first lung was inflammation, the surface of the lung has masses of dark pink blood. Cutting lung, people see plenty of larvae. Adult worms which parasitize in the small intestine slightly inflame mucous layer with appearance of mucus. Haemorrhage and peritonitis appear as a result of the perforation the gut.
8 .Diagnosis:
+ Pigs under 2 months of age: Although piglets have roundworms in the gut, roundworms have not laid eggs yet ( only lay from 54 to 62 days after migration and development in pig). Autopsy for diagnosis is necessary in search of larva at liver and lung.
+ Pigs over 2 moths of age:
How to find the eggs: The examination of fecal samples by method of Fulleborn.
Otherwise, people can make an autopsy to find in the small intestine.
+ Diagnosis by intradermal/intradermical injection: There are many ways to produce antigen for giving an injection into the skin, normally we use the method of Ecsop: cleaning roundworms alive with water, we crush them, then mix 2 parts of water, add 10 ml chloroform and 8 g enzyme of pancreas to every 1 ml of above mixture, adjust pH = 7,6-7,8. Having kept warm this solution for 7-12 days, the whole roundworms dissolved will be centrifugal, pour this solution into phial in which has alcohol 90 o, ratio 1:5, when antigen lie, take this antigen at the bottom of the vial, then continue to keep warm. It’s possible to keep up dry antigen in the refrigerator for over 8 months without influence on the antigen properties. This antigen will be diluted for test with ratio of 1:200. It is able to stick in the outer circle of ear or drop to eye-conjunctiva.
Diagnose methods are very good, no cross reaction in pigs infected withTrichocephalus suis, Oesophagostomum and Macracanthorhynchus hirudinaceus. Having been infected Ascaris suum from the eighth day to the eleventh day, pigs begin with a positive reaction. This reaction maintains between 110-140 days. After infection, metamorphosis response and concentration of antibody which appear at the same time and depend on adult worm in the intestine.
+ Do Duong Thai (1969) prepared antigen: Dead roundworms are mixed with physiological solution containing 5/1000 phenic acid. Le Ngoc My (1970) used this antigen. Its result is 65-80 % compared to examination of feces.
9. Treatment and prevention:
9.1 Prevention:
Pigsite is always clean, feeding trough and tool for livestock have been periodically disinfected. The best thing to do is disinfection feeding trough and tool every 10 days by boiling water. Rotting manure fecal matter will kill eggs, prevent from the spread of Ascaris suum.
Eggs are also destroyed by the physico-chemical methods Bredding farms which have lots of infected pigs with roundworm should be periodically disinfect, at least once a quarter, at the floor with boiling quarter. In cold seasons, the process of eliminating parasite from pigsty or surroundings by daily good sweep.
-The use of one of parasiticide for the weaned young pig and pig in 3-4 of age. If it is necessary we can use parasiticede for pig from 5-7 months old. Infectious rate of adult pigs which is lower, spreading roundworm showed that adult pigs are source of disease, so using parasiticede to kill roundworm in the pig-gut is encouraged.
-Pregnant sows: Use piperazin 200-300 mg/kg body weigh before producing.
-Raise resistance of pig by providing enough food, both quantity and quality, drinking-water is not pollution, examine health of pigs before taking pigs to farm.
Vaccine against Ascaris suum:
Ascariosis is traditionally being controlled by mass therapy with anthelmintics. Despite the high efficacy of these products, the long term effect of the anthelmintics is disappointing and the problem with ascariosis is actually increasing. The most important reason for this is the high fecundity of Ascaris suum (a female worm can produce up to 800.000 eggs/day) which causes a highly contaminated environment and the short activity of the anthelmintics. Only vaccination could result in a long-term, efficient control.
There were many tests in vaccination trials in the world. In Vietnam, a scientific test in preparing and using vaccine against Ascaris suum with embryo of roundworm eggs, and the effect of radioactive ray (1000r), the number of eggs is 500-1000 in a dose of vaccine. Safe vaccine; larvae which went through lung did not damage a lot, and they could not become adult roundworm in the gut. The rate of worm infection in pigs, are protected by the vaccine reduced 4.7 times compared with the infection in control pigs, the immune period is about 4 months.
.9.2 Treatment:
Pigs were infected with roundworm, use one of the following drugs:
- Tetramisole (Nilverm or Ascaridin): 20g / kg of body weigh, mixed with food or drink once.
-Levamisole (Vinacor, Decaris): 7.5% in aqueous solution
Intramuscular injection 6-8 mg / kg of body weigh for pigs which are less than 30 kg, 5-6 mg/kh of body weigh for pigs which are above 30 kg.
-Tetravermex: 10% powder, the dose of 20 mg / kg of body weigh for eating or drinking.
- Themisole: 15% , 200 ml/ bottle. Intramuscular injection dose of 1 ml / 20 kg of body weigh, not more than 5 ml / pig
- Nilverm: Produced in Australia , 7.5% concentration , 500 ml /bottle, 7-8 kh of body weigh.
- Nichlozamide-Tetramisole B: 5 g, 1 tablet for 75 kg of body weigh.
- Piperazine: only use (eating or drinking)Hexahydrate piperazine and mineral salt such as Adipinat, phosphate, sulfate. 0,3 g/kg of body weigh for pigs which are less than 50 kg in weight, and 15 g/kg of body weigh for pigs which are over 50 kg twice a day.
- Mebendazole (Mebenvet): 20 mg / kg of body weigh by eating or drinking. After using, pigs can be mild diarrhea.
- Dichlovos (DDVP): 0.2 g / kg P by eating or drinking.
- Benacine: 150 mg / kg of body weigh by eating or drinking.
- Phenothiazine: 0,5 g / kg of body weigh by eating or drinking. Phan Dich Lan (1962) proposal for two consecutive mornings, resulting in a 70-100% worms.
- Ivermectin: 0.1 to 0.3 mg / kg of body weigh injected intramuscularly or subcutaneously. According to Luc Phan, Nguyen Duc Tam (2000)[3], the drug proved effectively against adult worms form and the fourth-stage larvae
- Doramectin: 0.1 to 0.3 mg / kg of body weigh injected intramuscularly or subcutaneously.
- Also can use: Safersan, Morantel, benzimidazole, Febantel, Panacur, Parbendazole, Rintal, ...
- Leucaena leucocephala seeds: Dry, roast, grind. 60-100 g / pig. Mix with bran, dose depend on age Use continuously for 3 days.
- Old areca nut: 5-20 g/pig, boil then mix with good food. Feed pig.
Chapter 2
METHOD AND CONTENT OF STUDY:
1 . Method and object:
1.Object of study : under 4 month old pigs in the private farm, at 4/19 communes in Dien Khanh district. The reason for choosing 4 communes 4 is to represent 4 areas of the District (East South West North). The communes which were representative of each area had pigs the most.
1.2 Materias:
- Fecal samples of under 2 month old pigs
- Fecal samples at pigsty
- Saturated solution of salt (NaCl)
- Optical microscopes and test instruments
1.3 Helminthic is available at local
1.4 Time:
2.Content of study:
2.1 Study some major characteristics of pigs infected with Ascaris suum.
Adult pigs, clinical signs were not clear until intestinal obstruction and intestinal perforation or worms which got into the biliary duct causes jaundice.It causes stunt, lost weight.
Under 4 month old pigs, the larvae move through the lungs, then cause of getting pneumonia, cough and congestion. Depending on the intensity of infection, a large number of worms cause intestinal inflammation, diarrhoea , anaemia and gradually thin.
Assess prevalence of Ascaris suum every age, clinical signs of parasitic infection every pig, we rely on results of test by Fulleborn method
2.2 Survey the situation Ascaris suum infection diagnosed by Fulleborn method:
Add 1 liter of hot water to 380 g NaCl, or boil, then add salt slowly, stir until salt is insoluble again, allow to get cold until a thin layer crystallized on surface, filtration through cloth or cotton, remove sediment.
Take 5-10 g assigned to a small glass, crushed by a glass chopstick, we both crush up and pour into solution of saturated salt , about 40-50 ml, then filtered through cloth or steel net, take a little of solution a small cup, not move from 30 minutes to 1 hour, eggs will float above. Use a ring with diameter 5 mm to pick up a thin layer emerge, put on a glass, cover a glass leave. Watch microscope. Could pour salt water to a test-tube (20x50 mm), stop when level of water up near to mouth of test-tube, not move for a moment, then fish out layer which floats on solution by steel net. Place on board of glass to watch.
Count eggs by Mc. Master, if there are above 1000 eggs, that means pigs are infected severely. Every 4 g feces is in a glass, add 56 g solution of saturated salt, stir until dissolution. Filter by the net, pour into another cup, stir. Stirring the solution, absorb the solution by a medical instrument, devise 2 bunches Mc.Master( each bunch has 0,5 ml), not move for 5 minutes , then check by microscope.
All eggs of 2 counting-bunches are the number of eggs in 1 ml of fecal solution.
Commune Number of pigs tested Number of pigs infected with Ascaris suum Rate
METHOD AND CONTENT OF STUDY:
1 . Method and object:
1.Object of study : under 4 month old pigs in the private farm, at 4/19 communes in Dien Khanh district. The reason for choosing 4 communes 4 is to represent 4 areas of the District (East South West North). The communes which were representative of each area had pigs the most.
1.2 Materias:
- Fecal samples of under 2 month old pigs
- Fecal samples at pigsty
- Saturated solution of salt (NaCl)
- Optical microscopes and test instruments
1.3 Helminthic is available at local
1.4 Time:
2.Content of study:
2.1 Study some major characteristics of pigs infected with Ascaris suum.
Adult pigs, clinical signs were not clear until intestinal obstruction and intestinal perforation or worms which got into the biliary duct causes jaundice.It causes stunt, lost weight.
Under 4 month old pigs, the larvae move through the lungs, then cause of getting pneumonia, cough and congestion. Depending on the intensity of infection, a large number of worms cause intestinal inflammation, diarrhoea , anaemia and gradually thin.
Assess prevalence of Ascaris suum every age, clinical signs of parasitic infection every pig, we rely on results of test by Fulleborn method
2.2 Survey the situation Ascaris suum infection diagnosed by Fulleborn method:
Add 1 liter of hot water to 380 g NaCl, or boil, then add salt slowly, stir until salt is insoluble again, allow to get cold until a thin layer crystallized on surface, filtration through cloth or cotton, remove sediment.
Take 5-10 g assigned to a small glass, crushed by a glass chopstick, we both crush up and pour into solution of saturated salt , about 40-50 ml, then filtered through cloth or steel net, take a little of solution a small cup, not move from 30 minutes to 1 hour, eggs will float above. Use a ring with diameter 5 mm to pick up a thin layer emerge, put on a glass, cover a glass leave. Watch microscope. Could pour salt water to a test-tube (20x50 mm), stop when level of water up near to mouth of test-tube, not move for a moment, then fish out layer which floats on solution by steel net. Place on board of glass to watch.
Count eggs by Mc. Master, if there are above 1000 eggs, that means pigs are infected severely. Every 4 g feces is in a glass, add 56 g solution of saturated salt, stir until dissolution. Filter by the net, pour into another cup, stir. Stirring the solution, absorb the solution by a medical instrument, devise 2 bunches Mc.Master( each bunch has 0,5 ml), not move for 5 minutes , then check by microscope.
All eggs of 2 counting-bunches are the number of eggs in 1 ml of fecal solution.
Commune Number of pigs tested Number of pigs infected with Ascaris suum Rate
Dien An 50 15 30%
Dien Xuan 63 20 31.74%
Dien Lac 26 5 19.23%
Suoi Hiep 40 8 20%
Total 179 48 26.82 %
According to Dien Khanh district Veterinary Station (2003), infection rate ofAscaris suum recorded in the households which raise pig, a random survey at 87 pigs under 4 months of age is 38.27%, among the pig is 6 severe infection. There are not severe case any more now.
Dien Xuan 63 20 31.74%
Dien Lac 26 5 19.23%
Suoi Hiep 40 8 20%
Total 179 48 26.82 %
According to Dien Khanh district Veterinary Station (2003), infection rate ofAscaris suum recorded in the households which raise pig, a random survey at 87 pigs under 4 months of age is 38.27%, among the pig is 6 severe infection. There are not severe case any more now.
Chapter 3
RESULTS AND DISCUSSION
Effectiveness of drugs which are against Ascaris suum being used at local.
Currently, along with the application of advanced technologies in agriculture, pharmaceutical industry of veterinary constantly develops to support in time for developing husbandry. Besides the expansion model of farm breeding, raising pigs in household develop more and more…. Veterinary sciences and techniques become popular and widen everywhere, especially in the field of veterinary medicine.
Many drugs used widely, it is Levamison (Hanvet), Viamectin 25 or Vialevamysol (Viavet firm). Recently Delifluyke of Bayer Company has advised farmer worming the pigs by Delifluyke every 3 months for pig meat and every 6 months for sows. Safe medicine after using for pigs are remarked. Result of checking feces a week later follows:
Commune Number of pigs tested Number of pigs infected with Ascaris suum Rate
RESULTS AND DISCUSSION
Effectiveness of drugs which are against Ascaris suum being used at local.
Currently, along with the application of advanced technologies in agriculture, pharmaceutical industry of veterinary constantly develops to support in time for developing husbandry. Besides the expansion model of farm breeding, raising pigs in household develop more and more…. Veterinary sciences and techniques become popular and widen everywhere, especially in the field of veterinary medicine.
Many drugs used widely, it is Levamison (Hanvet), Viamectin 25 or Vialevamysol (Viavet firm). Recently Delifluyke of Bayer Company has advised farmer worming the pigs by Delifluyke every 3 months for pig meat and every 6 months for sows. Safe medicine after using for pigs are remarked. Result of checking feces a week later follows:
Commune Number of pigs tested Number of pigs infected with Ascaris suum Rate
Dien An 15 15 100%
Dien Xuan 20 17 85%
Dien Lac 5 4 80%
Suoi Hiep 8 8 100%
Total 48 44 91.66%
Dien Xuan 20 17 85%
Dien Lac 5 4 80%
Suoi Hiep 8 8 100%
Total 48 44 91.66%
We do not evaluate the effect of each medicine, only survey safe level of medicine when veterinarian used exactly dosage printed in label. Overall evaluation of effect on roundworm by Fullerborn method a week later.
Parasiticide which killed roundworm of pig was circulating in Dien Khanh district, Khanh Hoa province . Its result is 91.66%
CONCLUSIONS AND SUGGESTIONS:
1.Conclusion:
-Prevalence of Ascaris suum in pigs under 4 months old raised at private farms of four communes in Dien Khanh district, Khanh Hoa province, it changed from 19.23% to 31.74 %.
-Seriously infected pigs (assessed by method of count eggs Mc Master method) was 6.8% (2003). Currently, no pigs are infected severely.
-The average effect of drugs on the worms in Dien Khanh district, Khanh Hoa province is 91.66%
2.Suggestion:
- State of Ascaris suum infection at private farm in Dien Khanh district, Khanh Hoa province is still popular, so clean pigsite, a periodical prevention of disease with parasiticide and fresh enviroment are indispensable matter.`
-Look after pig with enough nutrient
-A variety of parasiticide is supported, so veterinary officer should make a survey of drug efficacy, economical and convenient the most, it is possible to apply the whole district.
REFERENCES:
1. Nguyễn Văn Diên(2011), “Bài giảng bệnh Ký sinh trùng thú y”, Trường Đại học Tây Nguyên, tr.164-166.
2. Đào Trọng Đạt, Phan Thanh Phượng, Lê Ngọc Mỹ(1995),Bệnh đường tiêu hóa ở lợn, Nxb Nông Nghiệp, tr.178-179.
3. Phan Lục, Nguyễn Đức Tâm(2000), Nhận xét về phát triển của ấu trùng giun đũa lợn trong giun đất Perionyx excavatus, Tạp chí Khoa học Kỹ thuật thú y, Tập VII,(số 2), tr.41-45.
4. Trịnh Văn Thịnh, Đỗ Đương Thái (1978), Công trình nghiên cứu Ký sinh trùng ở Việt Nam, Nxb Khoa học Kỹ thuật, tr.232.
5. Trịnh Văn Thịnh,Phan Trọng Cung, Phạm Văn Khuê, Phan Lục (1982), Giáo trình Ký Sinh Trùng thú y, Nxb Nông nghiệp, tr.110-113.
6. Nguyễn Phước Tương(1999),”Những bệnh Ký sinh trùng của lợn lây sang người”,Tạp chí Khoa học Kỹ thuật thú y, Tập VI, (số 1), tr.75.
7. Viện sĩ K.I SKRJABIN, Giáo sư A. PETROV(1979) Nguyên lý môn giun tròn thú y, Nxb Khoa học và Kỹ thuật, tr. 96 -101.
Richard Fox –Lander University
8. Frequency rising “Parasites”.http://www.frequencyrising.com/parasitecleanse_Ascaris.htm[truy cập ngày 30/4/2/12]
9. Richard Fox, Lander University. Invertebrate Anatomy OnLine
http://webs.lander.edu/rsfox/invertebrates/ascaris.html [truy cập ngày 30/4/2/12]
10. The Merck Veterinary manual “Ascaris sp”
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/22602.html[truy cập ngày 30/4/2/12]
11.Vetparasitology of Ghent University
Development of a vaccine against Ascaris suum
http://www.vetparasitology.ugent.be/page1/page24/page24.html[tr/c:30/4/20
Parasiticide which killed roundworm of pig was circulating in Dien Khanh district, Khanh Hoa province . Its result is 91.66%
CONCLUSIONS AND SUGGESTIONS:
1.Conclusion:
-Prevalence of Ascaris suum in pigs under 4 months old raised at private farms of four communes in Dien Khanh district, Khanh Hoa province, it changed from 19.23% to 31.74 %.
-Seriously infected pigs (assessed by method of count eggs Mc Master method) was 6.8% (2003). Currently, no pigs are infected severely.
-The average effect of drugs on the worms in Dien Khanh district, Khanh Hoa province is 91.66%
2.Suggestion:
- State of Ascaris suum infection at private farm in Dien Khanh district, Khanh Hoa province is still popular, so clean pigsite, a periodical prevention of disease with parasiticide and fresh enviroment are indispensable matter.`
-Look after pig with enough nutrient
-A variety of parasiticide is supported, so veterinary officer should make a survey of drug efficacy, economical and convenient the most, it is possible to apply the whole district.
REFERENCES:
1. Nguyễn Văn Diên(2011), “Bài giảng bệnh Ký sinh trùng thú y”, Trường Đại học Tây Nguyên, tr.164-166.
2. Đào Trọng Đạt, Phan Thanh Phượng, Lê Ngọc Mỹ(1995),Bệnh đường tiêu hóa ở lợn, Nxb Nông Nghiệp, tr.178-179.
3. Phan Lục, Nguyễn Đức Tâm(2000), Nhận xét về phát triển của ấu trùng giun đũa lợn trong giun đất Perionyx excavatus, Tạp chí Khoa học Kỹ thuật thú y, Tập VII,(số 2), tr.41-45.
4. Trịnh Văn Thịnh, Đỗ Đương Thái (1978), Công trình nghiên cứu Ký sinh trùng ở Việt Nam, Nxb Khoa học Kỹ thuật, tr.232.
5. Trịnh Văn Thịnh,Phan Trọng Cung, Phạm Văn Khuê, Phan Lục (1982), Giáo trình Ký Sinh Trùng thú y, Nxb Nông nghiệp, tr.110-113.
6. Nguyễn Phước Tương(1999),”Những bệnh Ký sinh trùng của lợn lây sang người”,Tạp chí Khoa học Kỹ thuật thú y, Tập VI, (số 1), tr.75.
7. Viện sĩ K.I SKRJABIN, Giáo sư A. PETROV(1979) Nguyên lý môn giun tròn thú y, Nxb Khoa học và Kỹ thuật, tr. 96 -101.
Richard Fox –Lander University
8. Frequency rising “Parasites”.http://www.frequencyrising.com/parasitecleanse_Ascaris.htm[truy cập ngày 30/4/2/12]
9. Richard Fox, Lander University. Invertebrate Anatomy OnLine
http://webs.lander.edu/rsfox/invertebrates/ascaris.html [truy cập ngày 30/4/2/12]
10. The Merck Veterinary manual “Ascaris sp”
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/22602.html[truy cập ngày 30/4/2/12]
11.Vetparasitology of Ghent University
Development of a vaccine against Ascaris suum
http://www.vetparasitology.ugent.be/page1/page24/page24.html[tr/c:30/4/20
