PARASITOLOGIE

• Parasitoses in pigs and their eradication. [Parassitosi dei suini, obiettivo eradicazione. ]
• Our experience with peroral application of Ivermectin in therapy of swine endoparasitosis. [Nasa iskustva u peroralnoj primeni ivermektina u terapiji endoparazita svinja]
• A case report of swine kidney worm infection in a wild feral pig.
• Enhancement of disease and pathology by synergy of Trichuris suis and Campylobacter jejuni in the colon of immunologically naive swine.
• Mange (Sarcoptes scabiei) eradication through sow treatment with ivermectin and validation by slaughter checks and ELISA assays.
• Mange demands decisions.
• Mange diagnosis.
• Australian actions.
• Mange detection.
• Dutch certification.
• Mange still a threat.
• Nematode names.
• A. suum incidence.
• Ascaris suum eradication?
• A. suum diagnosis.
• Impact of A. suum.

Parasitoses in pigs and their eradication. [Parassitosi dei suini, obiettivo eradicazione. ]
MOSSINI A.
Rivista di Suinicoltura, 2002, 43: 91-93
Parasitoses are fairly common in pigs in Italy. Of 23200 pig carcasses investigated in 1998, 52% were affected by ascariasis (Ascaris suum), and 68.2% of piglets in 44 herds examined in 2001 were affected by coccidiosis. Endoparasitoses and ectoparasitoses lead to loss of appetite, stress, poor feed conversion efficiency and susceptibility to other illnesses. Methods of preventing and eradicating parasitoses are considered.

Our experience with peroral application of Ivermectin in therapy of swine endoparasitosis. [Nasa iskustva u peroralnoj primeni ivermektina u terapiji endoparazita svinja]
PAVLOVIC I, LAZAREVIC M, TRIFUNOVIC M, CVETKOVIC A, CUKIC M, ZUTIC M, BRANKOV A.
Veterinarski Glasnik, 2002, 56: 211-218
Endoparasitic infections present a frequent health problem among swine maintained in farms. The most frequent diseases are ascariasis and oesophagostamosis. There are several valid methods in controlling parasites in swine, peroral application of antiparasitics and their subcutaneous application. Ivermectin is an antiparasitic with a wide range of effects and has been successfully used in curbing ecto- and endoparasites in swine and other animals. Ivermectin has so far been primarily applied subcutaneously, which required considerable efforts and the need for numerous staff in therapy of large agglomerations of farm animals. In recent years, ivermectin has appeared in powder form and is mixed in feed, which largely facilitates therapy and prevention of ecto- and endoparasitoses in farm animals. The efficiency of the peroral application of ivermectin in treating endoparasitic infections was examined. Ascariasis and oesophagostamosis in farm swine was controlled using peroral application of ivermectin. Four control examinations after therapy showed that there were no parasite infections. This indicated that ivermectin was efficient in controlling infections when applied perorally. Peroral application of ivermectin is a successful therapy for endoparasitic infections in swine, and is not in any way less efficient than its subcutaneous application. Moreover, peroral application of ivermectin largely facilitates therapy and the prevention of parasitic infections of farms with large agglomerations of animals.

A case report of swine kidney worm infection in a wild feral pig.
SUH MYUNGDEUK; SHIN GEEWOOK; KIM CHONGSUP; KWAK SOODONG; KIM SOONBOK; YEON SEUNGCHAN
Korean Journal of Veterinary Research, 2002, Vol.42, No.1, 109-113
This is the first case report of Stephanurus dentatus infection of a feral pig in Korea Republic. In late April 2000, a weakened feral pig was caught by blow gun from a very low level mountain near the Gyeongsang National University. We autopsied the feral pig in the laboratory of veterinary anatomy at the College of Veterinary Medicine. A total of 27 adult parasites, 11 females and 16 males, and numerous eggs were observed from the cysts formed in the perirenal tissues and ureters. The average size of males was 25.1 plus or minus 3.2 mm long and of the females was 34.2 plus or minus 2.9 mm. The worms were stout, the females being about 2 mm broad and the internal organs were partly visible through the cuticle. The shape of thin-shelled eggs found in the cysts of perirenal tissues and ureter was ellipsoidal and oval and measured 40-65 x 90-115 micro m. The adult parasites were found in cysts which varied from 0.6 to 4 cm in diameter, each cyst usually containing a pair of adult worms embedded in green pus. The ureter was thickened and almost occluded, with consequent hydronephrosis.

Enhancement of disease and pathology by synergy of Trichuris suis and Campylobacter jejuni in the colon of immunologically naive swine.
Mansfield LS, Gauthier DT, Abner SR, Jones KM, Wilder SR, Urban JF.
Am J Trop Med Hyg. 68:70-80.
Campylobacter jejuni, a leading cause of bacterial gastroenteritis, has different age distribution and disease expression in developing and developed countries, which may be due to the endemnicity of infection and the age of acquisition of immunity. Differences in disease expression are not solely dependent on the C. jejuni strain or virulence attributes. Another modulating factor in developing countries may be endemic nematode infections such as Trichuris, which drive type 2 cytokine responses and down-regulate type 1 immune responses. In this study, three-day-old germ-free pigs given dual infections with Trichurissuis and C. jejuni had more frequent, more severe diarrhea and severe pathology than pigs given no pathogens, only T. suis, or only C. jejuni. These pigs had significant hemorrhage and inflammatory cell infiltrates in the proximal colon where adult worms were found, and abscessed lymphoglandular complexes in the distal colon with intracellular C. jejuni. Pigs given only C. jejuni had mild clinical signs and pathology, and bacteria in feces or extracellular sites. Pigs given T. suis or no pathogens had no disease and minimal pathology. Thus, these agents synergized to produce significant disease and pathology, which was site specific.

Mange (Sarcoptes scabiei) eradication through sow treatment with ivermectin and validation by slaughter checks and ELISA assays.
CARGILL C, GARCIA R, HOMER D, SANDEMAN M.
Proceedings of the 19th Meeting of the World Association for the Advancement of Veterinary Parasitology, New Orleans, Louisiana, USA, August 10-14, 2003
Three mange elimination programs were constructed based on pig flow and other management factors. The first two were for use with continuous pig flow, and the third with batch farrowing. The first program involved medication of all sows and boars with ivermectin by injection on the same day, repeated 14 days later. The second program was to treat dry sows and boars with ivermectin in the feed for 7 days and repeat after a 7-day break, while lactating sows were treated by injection on the day in-feed treatment commenced and 14 days later. In the third program sows were treated with ivermectin by topdressing their feed for 7 days pre-farrowing and pre-weaning, while all boars were treated whenever a batch of sows was treated. Two farms were enrolled to each program, using manufacturer’s recommended dose rates. Sows examined before treatment were positive for both Sarcoptes mites and eggs while those examined 6 months after treatment were negative for mites and mite eggs. Slaughter pigs weaned before treatment had Average Dermatitis Scores (ADS) indicative of mange, while those weaned 6 and 12 months after treatment had ADS below the mange threshold. ELISA scores of piglets 6 and 12 months post-treatment did not indicate exposure to mites. Average daily gain (ADG) of pigs weaned 6 to 9 months after treatment were 1% to 5% higher than ADG of piglets weaned before treatment, demonstrating the productivity gains that can be achieved by eradicating mange.

Mange demands decisions.
GEURDEN T, VERCRUYSSE, J.
Pig Progress, June 2003: 4-6
Mange infestation is acquired by direct contact with infested animals and rarely from the environment; therefore control or eradication efforts must take this into account. First, a decision must be made whether to control mange or eradicate it. Eradication is required in top breeding farms, and strongly advised in production farms, but in finishing facilities a continuous control program may suffice to limit economic loss. Continuous control should start with treatment of all animals on the farm. Sows and gilts should all be treated two or three times a year; if macrocyclic lactones (ML) are used, piglets may not need to be treated. Boars should be treated four to six times per year to eliminate them as potential reservoirs of infestation. A single treatment of piglets at the beginning of the fattening period will at least delay onset of clinical infestation and reduce the severity. Eradication of mange has been successfully applied in many countries, and is best accomplished with two courses of treatment with a ML product such as in-feed ivermectin. Any pigs that do not consume enough feed during this treatment should be treated with an injectable ML. Failure of eradication programs usually are due to inadequate biosecurity barriers between treated and non-treated animals. After eradication, it is necessary to quarantine and treat any new stock entering the breeding herd, and to maintain biosecurity and monitoring for signs of mange.

Mange diagnosis.
VERCRUYSSE J, GEURDEN T.
Pig Progress, June 2003: 7-8
Current antiparasitic treatments are recommended without actually knowing the status of the pigs on a farm. This is due to difficulties in diagnosis, the high cost of laboratory tests compared to the cost of antiparasitic treatment, and the lack of advice on diagnosis in routine parasite control programs. Sarcoptic mange, caused by the Sarcoptes scabiei var suis mite, can be diagnosed as follows: On the farm, the presence of crusts in the ears is often diagnostic of mange, and should be confirmed by ear scrapings of growing pigs. High levels of pruritus (a scratching index of >0.4 scratching incidents per fattening pig per quarter hour) are suggestive of mange, but lack specificity and sensitivity. Conclusive diagnosis requires a finding of mites in ear scrapings. Recently, serological tests (ELISA) have been developed to demonstrate specific antibodies to S. scabiei. There are several considerations when using these tests – Specificity is high, but sensitivity is low in sows. Sensitivity of 60% in currently-available commercial tests is achieved by high cut-off points. These tests are not quantitative, and antibodies may remain detectable for 6-9 months after treatment in chronically infested animals. Young animals may not have developed specific antibodies perhaps due to interference of maternal antibodies. At the slaughterhouse, mange is diagnosed through the examination of carcasses for skin lesions. Dermatitis scores have been shown to have specificity of at least 75-80%. However, in using dermatitis scores diagnostically, it must be remembered that other parasites such as lice, Demodex mites and allergic reactions can also cause dermatitis.

Australian actions.
CARGILL C.
Pig Progress, June 2003: 9-10
In Australia, eradication programs have been validated across a range of production systems from continuous flow to all-in, all-out. In continuous flow herds, eradication is achieved either through treating all sows and boars twice with Ivomec Injection twice, 14 days apart, or by a combination of use of Ivomec Premix and Ivomec Injection, with two courses of treatment. In batch-farrowing herds, all pigs were treated twice by either route of administration; any pigs given ivermectin in the feed that did not consume all the medicated feed were treated by injection; treated sows were then isolated from non-treated animals and boars were treated before contact with treated sows. Eradication by any of these programs was demonstrated by decreases in dermatitis scores in market-weight pigs, by lack of anti-Sarcoptes antibodies in market pigs, and by improved growth rates. Other programs meant to control mange rather than to eradicate it are based on periodic treatment of all sows and boars at set intervals plus piglet treatment at weaning or on sow treatment before farrowing. These control programs can keep mange at low levels, if an effective product is used, and biosecurity is maintained after treatment.

Mange detection.
SANDEMAN M.
Pig Progress, June 2003: 10
A serological test will be available commercially late in 2003 to detect the presence of antibodies to mange mites in young pigs and/or pigs sent to slaughter. The new test is both highly specific and highly sensitive. It would be used on serum samples obtained from growing pigs on the farm, or from samples collected at the time of slaughter. Tests would have to be repeated over a period of at least 12 months in order to certify a herd as mange-free. With an eradication program in place, all new pigs entering the herd would have to be quarantined before any contact with the herd was allowed.

Dutch certification.
RAMBAGS P.
Pig Progress, June 2003: 11
The Animal Health Service (AHS) chose the use of Ivomec Injection (two injections 14 days apart) as the standard protocol to be used in herds to be certified mange-free. Only 1.5% of herds failed certification – half of the failures were due to import of mange-positive pigs; one fourth due to incorrect or omitted dosing of some pigs; and one fourth to unknown causes. Since 2000 other methods have been accepted by AHS, including use of Ivomec Premix. Use of Dectomax by injection has also been used by AHS, but inexplicable failures have been observed. Starting 8 months after eradication, a certfication as mange-free requires: no clinical signs of mange; no use of miticides since eradication; scratching index <0.4; negative ear scrapings; and any introductions to the herd must be mange-free pigs on mange-free trucks.

Mange still a threat.
MELANCON J.
Pig Progress, June 2003: 12
Changes in management systems in the North American swine industry have led to decreased prevalence of mange. However, the industry has also become less concerned about the effects of mange, although the effects can be extensive. Growing pigs may have decreased weight gain, feed conversion, and carcass value and increased hide damage. Sows may have smaller litters with lower weaning weights, and productive sow days may decrease. As yet, there is no serum test for mange diagnosis in North America. Thus, mange is diagnosed through clinical signs and lesion scoring. These methods are time-consuming and may lack sensitivity. Slaughter checks, although used less now that several years ago, may be the best method for diagnosing mange. Random prevalence surveys conducted in the United States in 2002 and in Canada in 2003 demonstrate that mange still persists at levels that cause economic losses. This should be a concern to the industry, especially since it is a disease that can be eradicated with management compliance.

Nematode names.
STEWART TB.
Pig Progress, June 2003: 13
Ascaris suum is the largest and most common nematode parasite of swine; the egg can remain dormant for long periods of time until favorable conditions for development occur. Early treatment during the migration stage is of economic benefit. Oesophagostomum dentatum is more important in older pigs than in young ones; strains found in the UK seem to be more pathogenic than those seen in the US. Trichuris suis eggs can also persist in the environment for long periods of time; heavy infections cause severe bloody diarrhea and may cause death. Strongyloides ransomi, Metastrongylus spp. and Hyostrongylus rubidusare all more common when pigs are raised outdoors. Stephanurus dentatus is only found in warm temperate areas.

A. suum incidence.
DE BIE S.
Pig Progress, June 2003: 14-15
Ascaris suum infection is common in many European countries. In a recent survey, white spots were found at rates of 4.3% to more than 50% of livers from slaughter pigs. In a single herd, the rate of infection can vary from batch to batch, due to the epidemiology of the parasite. Liver spots reflect the number of larvae present in the pig during the five weeks prior to examination. Embryonated eggs ingested by the pig hatch and migrate out of the small intestine within 24 to 48 hours. They then migrate to the liver and then to the lungs. About 2 weeks after ingestion, the worms arrive in the intestine, where they complete their development. Economic losses, estimated at about 3.5 euros per slaughtered pig, are caused by the direct damage to the liver and lungs, by the slower growth rate that ensues, and the condemnation of livers.

Ascaris suum eradication?
ROEPSTORFF A.
Pig Progress, June 2003: 16-17
A. suum is often the last parasite infecting pigs in intensive production systems. It is still debated how to eradicate this parasite using optimal deworming programs. Ascaris was present in a few animals in some herds in which worms were never found in fatteners or sows. Ascaris may be reduced to negligible levels or even eradicated by optimal hygiene and appropriate pen design that increases desiccation and thereby mortality of the eggs. In such lightly infected herds Ascaris does not usually constitute a problem and eradication may therefore not be cost-effective. Herds that would benefit markedly from Ascaris eradication are the heavily infected herds, but in such herds drug treatment programs without improved hygiene standards presumably have to be extremely intensive and long-lasting, and if successful at all, the herds will be very susceptible to reinfection due to the presence of microhabitats favorable for egg survival.

A. suum diagnosis.
VERCRUYSSE J AND GEURDEN T.
Pig Progress, June 2003: 18
Diagnosis of A. suum infection is accomplished by findings of high fecal egg counts (>10,000) in pigs over 10 weeks of age. Piglets are protected by colostral antibodies for about 3 weeks, and then patency requires about 6 weeks after ingestion of embryonated eggs. It is recommended that at least 10 litters of piglets be sampled and examined in the laboratory for eggs. Egg counts <200 EPG are considered false positives, caused by coprophagia. False negatives may be due to immaturity of the infection, or to the pigs developing immunity. As few as 30% of infected pigs may be positive for fecal eggs. White spots on the livers of slaughtered pigs are indicative of recent exposure to infective material.

Impact of A. suum.
URBAN J.
Pig Progress, June 2003: 22
The frequency and level of A. suum exposure skews the immune response unfavorably for the control of microbial pathogens, with severe consequences on pig performance. The effect of A. suum infection alone can be marginalized by good management. However, an appropriate immune response to microbial infection will be compromised when A. suum persists in the environment. While the impact of A. suum on particular infectious agents needs to be studied, a shift in antibody classes that accompanies a strong infection with A. suumwill impact not only on other infectious agents but on vaccination protocols that require specific arms of the immune system to be activated in order to be effective.