SVANOVIR® A. suum-Ab enables sero-monitoring of Ascaris suum infection

14th May 2018

Boehringer Ingelheim presents a new standard in monitoring Ascaris suum infection in pig herds, a practical and more accurate alternative to standard test methods.


Ascariasis is a subclinical disease affecting pigs worldwide caused by Ascaris suum (A. suum) the large roundworm of pigs, a highly prevalent helminth in pig production systems. Although the infection is subclinical, it is well documented that the parasite can cause significant economic losses for the pig farm. A serological test is both a more practical and accurate alternative to classical test methods (faecal egg counts and liver white spots).


The infection cycle begins when pigs ingest parasite eggs from the environment. Inside the gut, infective larvae will emerge from the egg and start to migrate. They use the blood system to get to the liver and subsequently the lungs to eventually reach the small intestine again where they can grow into adulthood. The infection affects the growth rate of the pigs with a reduced daily weight gain, increased liver condemnation rates and higher susceptibility to secondary infection, thus having an economic impact on production.


The classical methods for identification of infected herds are faecal egg count analysis or counting affected livers at slaughter. Both methods have their limitations. Within a herd only about 30% of the infected pigs will excrete parasite eggs. The majority of the larvae will be expelled from the intestine before the egg laying stage and therefore the use of egg per gram (EPG) count is not representative of the actual parasite exposure. The number of pig livers showing milk spots represent a degree of infection. This method is highly subjective especially in pig herds that show a lower degree of parasite burden. White spots resolve several weeks after infection and livers might therefore appear normal even though pigs had been infected. SVANOVIR® A. suum-Ab is an indirect ELISA based on A. suum haemoglobin thereby enabling the detection of antibodies to both the larval and adult stages of this parasite. Immunodiagnostics like the SVANOVIR® A. suum-Ab is far more sensitive, objective and reliable than any other currently employed diagnostic technique.


Control of the infestation levels can be achieved through repeated anthelmintic treatments, expelling all adult parasites from the gut. By repeating this treatment every 6 weeks contamination of the environment can be prevented. As the infection intensity drops over time, so will the antibody levels developed against these worms. With SVANOVIR® A. suum-Ab it is possible to measure exposure level and use the test results in management of the anthelmintic treatment, evaluating incidence and prevalence rates and improve control programs. This can enhance animal welfare and increase the productivity thus also the economics in pig production.


SVANOVIR® A. suum-Ab is a well validated assay for the semi-quantitative analysis of A. suum infection which clearly sets a new standard for the control of A. suum infection in fattening pig units.






References:

Vlaminck J., Nejsum P., Van Groenweghe F., Thamsborg S.M., Vercruysse J., Geldhof P. Evaluation of a serodiagnostic test using Ascaris suum haemoglobin for the detection of roundworm infection in pig populations. Veterinary Parasitology 2012 189 (2-4):267-73.

Vlaminck J.,Düsseldorf S., Heres L., Geldhof P. Serotological examination of fattening pigs reveals associations between Ascaris suum, lung pathogens and technical performance parameters. Veterinary Parasitology 2015 210(3-4):151-8

Martínez-Pérez J.M., Vandekerckhove E., Vlamink J., Geldhof P., Martínez-Valladares M. Serological detection of Ascaris suum at fattening pig farms is linked with performance and management indices. Veterinary Parasitology 2017 248: 33-38