PARASITOLOGIE

• Ascaris suum infection in slaughter pigs: pathological incidence and economical impacts in France
• Sarcoptic mange elimination in swine herds: evaluation with different diagnostic tools
• The value of faecal examination as predictive tool for Ascaris suum infections
• Cost effective control of Sarcoptes scabiei using IVOMEC pre-mix post-weaning
• Development of a new antibody ELISA for swine mange using meat extract samples
• Three mange eradication programs based on breeding herd treatment only validated by slaughter check and elisa assay
• Correlation between white liver spots and pneumonia: a slaughterhouse survey
• New alternatives for the use of IVOMEC premix in combinationwith IVOMEC injectable to eradicate sarcoptic mange in pig farms
• Acute respiratory distress and death caused by migrating larva of Ascaris suum in finishing pigs
• A comparison of the susceptibility of growing Mukota and Large White pigs to infection with Ascaris suum
• Production losses due to ascarid infestation of outdoor maintained pigs [Durch Spulwurmbefall bedingte Produktionseinbussen in der Freilandhaltung der Schweine]
• Helminth control practices and infections in growing pigs in France
• In-feed 0.6% ivermectin formulation for treatment of wild boar in the Moslavina hunting ground in Croatia
• The effect of management practices on the occurrence of intestinal nematodes in pigs
• Injectable 1% ivermectin anthelmintic activity in swine naturally parasitized [Atividade anti-helmintica da Ivermectina 1% injetavel em suinos naturalmente parasitados]
• Efficacy of ivermectin in swine food [Eficacia de una formulacion de ivermectina para uso en alimentos de cerdos]

Ascaris suum infection in slaughter pigs: pathological incidence and economical impacts in France
KANORA A, MEISSONNIER E, DESTOMBES T, DAGORN D
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 1, Page 241, Abstract No. 803.
A survey was conducted in 2002-03 to evaluate the incidence of liver lesions due to Ascaris suum infection in fattening pigs. The random survey was organized in six large slaughterhouses located in Brittany, the main region of pig production in France. Inspected animals were fattening pigs of which the body weight was from 100 to 110 Kg. In total 10,175 livers were observed with numbers varying from 486 to 2786 depending on each slaughterhouse. The incidences of livers with score 2 or 3 were dispatched between 15 % and 42 % by slaughterhouse and between 10 % and 65 % by pigs batch. Macroscopic and microscopic observations of recent and scar hepatic lesions confirmed the previous descriptions on Ascaris suum infection by different authors (2, 3, 4). They are easily explained because no routine deworming of fattening pigs is applied and the Ascaris infection is not controlled. The losses due to chronic hepatitis and microbial surinfections are considered as high if they are compared with the cost of 2 usual dewormings during the fattening period.

Sarcoptic mange elimination in swine herds: evaluation with different diagnostic tools
VYT P, HEYLEN P, DE SMET K, PEELAERS I, VERCRUYSSE J
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 1, Page 276, Abstract No. 504
Sarcoptic mange is affecting the production efficiency of swine worldwide. However, the availability of highly effective treatments makes elimination of sarcoptic mange possible. The Belgian elimination program for swine mange started in 2001. Three elimination protocols were used: (a) a double treatment with ivermectin (6 farms) on day 1 and 14 (by injection for adult animals and piglets and, in case of fatteners with in feed treatment), (b) a single doramectin injection (12 farms) (3) and (c) a combination of both drugs (5 farms). Diagnosis of sarcoptic mange was done before and 7 months after treatment. Before elimination mites were found on 3 farms and after elimination no mites could be detected. From the 5 farms with positive Rubbing Index (>0.4) before elimination, one farm remained positive after treatment. There was a decrease of the mean RI. The number of farms with at least two serologically positive animals was 15 before treatment and decreased to 8 after 12 months. The standard eradication protocol with two treatments with ivermectin rarely results in failures. However, inexplicable failures have been observed after the one-shot-injection with doramectin in the Netherlands. In one farm this observation seems to be confirmed by a rise in serologically positive animals 1 year after treatment with doramectin. Infection couldn’t be confirmed but further serology was positive. Since then, within the program, two administrations of doramectin are required. In conclusion we can say that even with the different diagnostic tools at hand, successful elimination of mange is hard to confirm. Strict control on treatment and biosecurity can prevent failure.

The value of faecal examination as predictive tool for Ascaris suum infections
AGNEESSENS J, KANORA A
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 1, Page 298, Abstract No. 667
Rational control of Ascaris suum infection is possible by hygienic measurements and the strategic use of anthelmintics. It is generally recommended that the implementation of such a control program should only start after the presence of infection is parasitologically confirmed (e.g. EPG or liver scoring). Two commercial fattening farms, with a known history of Ascaris infections were selected. On both farms 1 and 2, the results from the faecal examination suggest only a relatively low Ascaris infection during first part of the fattening period, up to week 21 However, towards the end of the fattening period, there was an important increase in the number of positive faecal samples. This indicates that the relative low number of egg-shedding pigs at the beginning of the fattening period, can be responsible for the contamination of the entire stable, and the spread of infection to the other animals. Not only are faecal examinations for Ascaris a weak predictor for the potential build up of infection pressure, the slaughterhouse results also clearly indicate that results from faecal examination underestimate the actual percentage of recently, or previously infected pigs. A large part of Ascaris infections are not properly treated or undertreated, because parasite levels are thought to be low, or thought to be not existing. Strategic use of anthelmintics should be programmed.

Cost effective control of Sarcoptes scabiei using IVOMEC pre-mix post-weaning
CARGILL C, SANDEMAN M, GARCIA R, HOMER D
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 567, Abstract No. 381
Despite the efficacy of current acaricides, Sarcoptic mange remains one of the most significant disease problems affecting production efficiency. Although elimination of mites from the breeding herd is the preferred option, eradication is not always practical. Hence elimination of mites from pigs post-weaning may be a viable alternative. The objective of this study was to validate the treatment of pigs post-weaning with IVOMEC pre-mix to eliminate Sarcoptes mites. In-feed medication with IVOMEC® pre-mix (inclusion rate 333g/t) for 20 days post weaning proved an efficacious method for reducing mite numbers in growing pigs. The fact that mites and mite eggs were not recovered from any medicated pigs when examined 84 days post weaning, and that dermatitis scores and ELISA values at slaughter were significantly lower than those recorded in pigs exposed to mites is strong evidence for mite elimination. Medicated pigs also grew more rapidly and more efficiently than non-medicated pigs, demonstrating the economic value of medication.

Development of a new antibody ELISA for swine mange using meat extract samples
VERCRUYSSE J, GEURDEN T
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 568, Abstract No. 501
Despite the availability of highly effective treatments, the mange mite Sarcoptes scabiei var suis continues to cause problems for the pig industry worldwide. Conclusive diagnosis is still difficult because of the minute size of the parasite, its location within the skin, and the nonspecific clinical signs, which include pruritus. Although serologic ELISA testing has proven successful in identifying infested herds, its use may be restricted due to difficulties in sampling (i.e. collection of serum). Meat extract samples offer the opportunity to reduce procurement costs and increase sample availability as meat extract samples can be readily obtained during the harvest process. This enables large numbers of market swine to be sampled while maintaining site traceability capabilities. Therefore, the potential for meat extract samples to be used as an antibody carrier for S. scabiei antibodies in swine was also investigated. A total of 106 samples (ear scrapings, serum and diaphragm meat) were collected at the slaughterhouse. Scrapings were examined microscopically for mites, and if negative, by KOH incubation. Sera and meat juice were tested using the Ghent assay. There was a good correspondence between the mean ODR of the serum and meat juice samples (correlation coefficient of 0.80), suggesting that meat juice may provide a useful diagnostic tool to determine if skin lesions are due to Sarcoptes. This test allows veterinarians, packers and producers to early identify low levels or subclinical stages of a mange infestation, which are often ignored or underestimated on a herd level.

Three mange eradication programs based on breeding herd treatment only validated by slaughter check and elisa assay
CARGILL C, SANDEMAN M, GARCIA R, HOMER D
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 572, Abstract No. 380
Although previous reports have described Sarcoptic Mange eradication programs based on whole herd treatment, few reports of treating only the breeding herd have been recorded. In this study, successful eradication based on breeding herd treatment alone was achieved and validated using mite counts, slaughtering monitoring and serology. In herds A and C, all sows and boars were injected S/C with IVOMEC. (1 mL/33 kg) twice 14 days apart. In herds B and D all dry sows and boars were medicated with IVOMEC. Premix (0.6% w/w) for two 7-day periods separated by an interval of one week. Lactating sows received the same treatment as herds A and C. In herds E and F, the daily rations of all sows in each sow batch, along with the herd boars, were top dressed for two 7-day periods with IVOMEC. Premix (0.6% w/w) diluted with lactating sow diet to provide a final dose of 100 mcg/kg BW/day. Sows were medicated for 7 days prior to transfer to the farrowing house and again for 7 days prior to weaning. Based on the negative live mite counts, and the absence of mite eggs in material scraped from the ears of sows and their progeny six and 12 months following treatment, as well as the negative ELISA results, the eradication of Sarcoptes scabiei mites from all herds was successful. This was irrespective of the method of treatment or the type of management system used on the farm.

Correlation between white liver spots and pneumonia: a slaughterhouse survey
VYT P, DE BIE S, KANORA A
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 582, Abstract No. 638
In practice, slaughterhouse data are frequently used to monitor disease problems at farm level. During a period of 3.5 years, 56 farms (51 mixed farms and 5 fattening farms) were monitored by recording individual data of all pigs slaughtered at the LVV plant at Lokeren, Belgium by the veterinarians responsible for the post-mortem examination. From the 152,364 pigs, 11.1 % of livers were condemned, 3.8 % had ‘pneumonia 1’ and 7.1 % had ‘pneumonia 2’. Farms with the AI-AO system (n=23) had less lesions (8.9 % liver, 3.2 % ‘pneumonia 1’ and 5.7 % ‘pneumonia 2’), than with a continuous (n=33) fattening system (15.4 % liver, 4.2 % ‘pneumonia 1’ and 7.85 % ‘pneumonia 2’). Our data reveal that 11 % of the livers is rejected at slaughter because of multiple white spots. The follow-up during a 3.5-year period confirms the level of the worm problem on the different farms. High liver and lung lesions were negatively correlated with the all-in/all-out management system. Even though we have no data on hygiene, stable climate or specific disease problems, AI AO is clearly an important tool in preventing both liver and lung lesions. In conclusion we can say that even with the modern knowledge on anthelminthic therapy, still a high number of livers is condemned at slaughter. A correlation between liver and lung lesions is present when liver lesions are not extremely high and both liver and lung lesions seem to be reduced when applying the AIAO management system.

New alternatives for the use of IVOMEC premix in combinationwith IVOMEC injectable to eradicate sarcoptic mange in pig farms
PONS D
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 586, Abstract No. 727
Successful mange eradication using IVOMEC® (ivermectin) Injectable alone or in combination with IVOMEC. Premix has been described. Effective use of a reduced dose of IVOMEC® Premix during a longer treatment period, with the same total dose of IVOMEC. (700 µg/kg) was recently reported; allowing more flexibility to the treatment in the field, and offering new opportunities for mange control and eradication. A mange eradication protocol based on the use of a combination of IVOMEC® Injectable and IVOMEC® Premix was used in a commercial 500 sows farrow-to finish farm following a similar approach as previous studies. Weaned piglets and growers in the pre-fattening period were treated with 70 µg ivermectin /kg/d during 21 consecutive days. Other classes of animals were treated twice, 14 days apart, by injection or with in-feed ivermectin. The high prevalence of mange before treatment and the efficacy of treatment was confirmed by clinical observation, calculation of the scratching index (SI) and detection of mites in ear scrapings. The results of this study confirmed the efficacy of a 70 µg ivermectin /kg/d treatment during 21 consecutive days in piglets in an eradication protocol under field conditions confirming previous experimental findings (7), as well as successful mange eradication with IVOMEC® Injectable in other treatment regimens.

Acute respiratory distress and death caused by migrating larva of Ascaris suum in finishing pigs
GJESTVANG M, LIUM B, GAMLEM H, GJERDE B
Proceedings of International Pig Veterinary Society 18th Congress, June 27-July 1, 2004, Hamburg, Germany, Volume 2, Page 841, Abstract No. 1519
Ascaris suum in pigs is commonly associated with liver white spots at slaughter, and may cause major economic losses due to liver condemnations, reduced growth rate and lowered feed conversion in growing pigs. Heavy ingestion of infective eggs of A. suum may lead to massive larval migration through the liver and lungs causing respiratory distress. Acute death is very seldom. This paper describes the clinical picture and pathological findings in pigs from a finishing farm with an acute outbreak of fatal ascariasis. At day one 40 pigs weighing approximately 25kg, arrived from a farrowing herd. The pigs were placed in a room containing one large pen covered with deep sawdust bedding, which remained after the previous batch of finishing pigs. Starting late on Day 5, the pigs showed symptoms of respiratory distress. Five died on Day 7 and another 10 on Day 8. Body temperatures were within a normal range. On day 9, only 14 pigs were still alive, all with very pronounced respiratory symptoms. They were all euthanized due to welfare reasons. At necropsy, the lungs were enlarged, heavy and firm with scattered petecchial bleedings and consolidations, and the lumen of the trachea and the bronchi contained foamy, mucoid fluid. There were scattered hemorrhagic foci in the liver parenchyma. Histological examination of the lungs revealed a large number of parasitic structures and a marked exudation of leucocytes in the lung parenchyma, alveoli and bronchioles. In the liver tissue multifocal necrosis with infiltrating leucocytes were found. The number of eggs of A. suum in the bedding varied from 320 to 1240 EPG, and most of the eggs contained living larvae, and hence were infective. The clinical, pathological and parasitological findings indicate that the pigs had become heavily infected with infective eggs of A. suum at the time they arrived to the new herd. The time span from the pigs entered the new pen and until the start of the clinical symptoms corresponds very well with the described period of 4-7 days from a pig ingests infective eggs, and till the larvae have migrated to the lungs.

A comparison of the susceptibility of growing Mukota and Large White pigs to infection with Ascaris suum
ZANGA J, CHIMONYO M, KANENGONI A, DZAMA K, MUKARATIRWA S
Veterinary Research Communications 27 ( 8 ): p 653-660 December 2003
The influence of A. suum infection on the haematology, liver-related serum enzymes, blood urea and live weight gain in Mukota and Large White (LW) weaner pigs was compared. Six pigs of each genotype were infected with a single dose of 4000 A. suum eggs per pig and another six were not. The pigs were kept for 100 days. Blood was collected daily for the first 7 days and also after 100 days. In the infected pigs, there was an increase (p< 0.05) in alanine aminotransferase (ALT) activity in the LW but not in the Mukota pigs. Although the alkaline phosphatase (ALP) activity rose (p< 0.05) in both infected and non-infected LW pigs from day 1 to day 3, the activity in the non-infected LW pigs then decreased, while that of the infected LW pigs remained elevated. The infected LW pigs had higher (p< 0.05) levels of ALT, ALP and aspartate aminotransferase than their non-infected counterparts. Non-infected LW pigs tended to have higher (p<0.05) haematological parameters, daily weight gain and urea concentrations than infected LW pigs, but these differences were not significant. These preliminary findings suggest that more A. suum larvae reached the livers in the LW than in the Mukota pigs and that the latter may be more resistant to A. suum infection.

Production losses due to ascarid infestation of outdoor maintained pigs [Durch Spulwurmbefall bedingte Produktionseinbussen in der Freilandhaltung der Schweine]
CLARK P, BILKEI G
Tieraerztliche Umschau 58 ( 8 ): p 425-431 1 August, 2003
The objective of this study was to examine the effects of ascarid infection in pigs raised outdoors. The study was conducted in a large Croatian pig breeding unit which comprised both indoor and outdoor production systems. Two hundred and seventy piglets were randomly assigned to one of three equally sized groups of (90) pigs. Group 1 comprised indoor reared pigs which remained untreated, Group 2 comprised outdoor piglets which remained untreated and Group 3 comprised outdoor reared pigs which were treated with Ivermectin intramuscularly at a dose of 0.3 mg/kg bodyweight on days 10, 30 and 50. The variables examined were: birth weight, slaughter weight at 60 days of age, average daily weight gain, eosinophil and white cell count at slaughter, bronchoalveolar lavage fluid (BLF), total cell count and white cell differential count at slaughter, lactate dehydrogenase (LDH) concentration in BLF at slaughter, liver pathology, pulmonary histopathological changes and procoagulant activity (PCA) in BALF. Pigs in Group 3 had statistically significant higher average daily weight gains, significantly reduced white blood cell counts, blood and BALF eosinophilia, MS, LDH and PCA than the animals in Group 2. The animals in Group 1 remained free of ascaris infestation.

Helminth control practices and infections in growing pigs in France
BELOEIL PA, CHAUVIN C, FABLET C, JOLLY JP, EVENO E, MADEC F, REPERANT J M
Livestock Production Science 81 ( 1 ): p 99-104 May 2003
Internal parasite control practices and helminth infestations were investigated in 78 pig farms in France. Pooled faecal samples were taken from pens housing 16-week-old pigs. Samples were examined by coproscopy. Farm practices were checked for the risk factors of infestation previously described in literature. Information was obtained during a visit of the facilities and an interview with the farm owner/manager. Anthelmintics were used in most herds (97%). Treatments were routinely prescribed, such as flubendazole in the diet of the piglets and ivermectin for sows. Finisher pig infestation may occur despite these treatments: five samples in our study contained helminth eggs, four samples contained strongylid eggs (Hyostrongylus rubidus or Oesophagostomum spp.), and one sample contained Trichuris suis eggs. We can conclude that helminths are controlled, but that parasites can still be present in indoor intensive pig operations. Hygiene efforts must be continued.

In-feed 0.6% ivermectin formulation for treatment of wild boar in the Moslavina hunting ground in Croatia
RAJKOVIC-JANJE R, MANOJLOVIC L, GOJMERAC T
European Journal Of Wildlife Research , 2004 , V 50 , N1 ( MAR ) , P 41-43
An in-feed 0.6% ivermectin formulation was administered for 7 days to wild boar piglets at three sites of the Moslavina hunting ground in Croatia. Examination of internal organs and skin of five piglets that died immediately before the start of administration of the ivermectin formulation revealed the presence of Metastrongylus apri and Metastrongylus pudendotectus in the lungs, and of Ascarops strongylina, Physocephalus sexalatus and Globocephalus urosubulatus in the gastrointestinal tract. Coccidial oocysts were found in the feces of all animals. Sarcoptes scabiei var. suis was identified in the skin of four piglets. The efficacy of treatment was assessed by examining fecal samples before start of therapy (day 0) and on days 7 and 14. Before treatment strongylid-type eggs were detected in 70-100% of fecal samples (210-505 EPG) The eggs of Strongyloides ransomi, Trichuris suis, Ascaris suum, Ascarops strongylina and Physocephalus sexalatus were identified in 10-50% of fecal samples at an intensity of 5-45 EpG. On day 14 after the start of the treatment, strongylid-type eggs were detected in 10% of fecal samples from one of the three sites only. Eggs of other helminth species were not detected at any of the three sites. This confirmed the successful therapeutic efficacy of the in-feed 0,6% ivermectin formulation.

The effect of management practices on the occurrence of intestinal nematodes in pigs
NOSAL, P.
Annals of Animal Science vol. 4 ( 1 ): p.163-171, 2004
A total of 2391 gilts, 8-10 weeks old, originating from 88 pedigree farms in Poland, were examined coprologically (1994-95). Nematodes were found in 25.1% of the population studied and the mean intensity equalled 1206 eggs per gram of faeces (epg). Ascaris suum and Oesophagostomum sp. were the predominant parasites, whereas Trichuris suis and Strongyloides ransomi eggs occurred only rarely. The gilts from larger herds (with a minimum of 25 sows in breeding stock) had significantly (P<0.05) lower chances of being infected compared with those from smaller farms (less than 25 sows per herd). Significant seasonal variations in the levels of helminth and A. suum infections were observed (P<0.01 and P<0.05, respectively), with the highest egg excretion in the summer months. The results suggested the great importance of management factors for the control and prevention of helminthosis in swine herds. 20 ref.

Injectable 1% ivermectin anthelmintic activity in swine naturally parasitized [Atividade anti-helmintica da Ivermectina 1% injetavel em suinos naturalmente parasitados]
TOMA SB, MOREIRA RJC, CANAVACI FHT
A Hora Veterinaria ( No.135 ): p.31-33, 2003
The objective of this work was to evaluate the anthelmintic action of one formulation of ivermectin 1% injectable in pigs. 18 male crossbred pigs (LW x 1/2 Piau/Duroc) received a dosage of one ml/33 kg of body weight (300 mg/kg). The maximum efficacy (100%) was observed against Ascaris suum, Metastrongylus apri, and Globocephalus urosubulatus. Efficacy values of 98.9, 99.9, and 99.6% were observed against Trichuris spp., Oesophagostomum dentatum, and Strongyloides ransomi, respectively.

Efficacy of ivermectin in swine food [Eficacia de una formulacion de ivermectina para uso en alimentos de cerdos]
PERALTA JL, BONO MF, RUIZ MF, ORCELLET VM.
Revista de Medicina Veterinaria (Buenos Aires) vol. 84 ( 1 ): p.12-13, 2003
Evaluation of an ivermectin formulation to be mixed with feed for swine naturally infested with gastrointestinal and pulmonar nematodes was carried out. 12 hogs were allocated into 2 groups, treated and untreated control. Treatment consisted of feed dosed with 333 g of ivermectin premix per 1000 kg of feed. An efficacy percentage (PE) of 100% was determined for Ascaris suum, Oesophagostomum dentatum, Trichuris suis, Metastrongylus apri, and M. pudendotectus and of 99.7% for Hyostrongylus rubidus. 6 ref.