Вплив вірусу трансмісивного гастроентериту на формування імунітету поросят

Abstract

В статті висвітлені проблеми формування імунітету у поросят при захворюванні вірусним трансмісивним гастроентеритом. На розтині були виявлені ознаки катарального запалення слизової оболонки шлунка та кишечнику. Рівень захворюваності на фермі на час обстеження складав 50 %, загибель – 30 % серед молодняку до місяця. У господарстві було проведене щеплення від мікоплазмозу поросят. На фоні захворювань поросят трансмісивним гастроентеритом у 75% тварин не сформувався імунітет. Тому на розтині були поросята з ознаками мікоплазмозу, що затрудняло постановку діагнозу.

Viral transmissible gastroenteritis of swine (TGS) is an acute highly contagious disease with signs of catarrhal hemorrhagic gastroenteritis and high mortality in piglets 1-10 days of age. In recent years, transmissible gastroenteritis is recorded in all continents of the world, especially in the countries with intensive pig farming. The disease is also widespread in the Ukrainian pig farms. Etiology, pathogenesis, clinical picture and treatment of this disease are sufficiently fully described in literature. But the data on the virus influence on the immunity formation during the illness is not fully described. The problem is that the transmissive gastroenteritis virus of swine violates the immune response as a result of the intestine lesion. Thus, when diseased animals are vaccinated, they have no immunity from the disease. In the organism of sick piglets, the virus accumulates in the epithelium of the small intestine, in the contents of the digestive canal, and in lungs. During the viremia, the virus can be found in parenchymal organs, as well as in the nasal mucous membrane, trachea, tonsils, and in the blood (with the low titre). The virus persists in the internal organs and lymph nodes of the recovered animals for many months and years. The article deals with the problems of the immunity formation in piglets having the viral transmissive gastroenteritis. Signs of catarrhal inflammation of the mucous membrane of the stomach and intestines were revealed at the autopsy. During the investigation on the farm, the incidence rate among piglets (1- 30 days of age) was 50%, death rate - 30%. The farm animals were vaccinated against the pigs mycoplasma. Since the piglets had transmissive gastroenteritis, immunity of 75% animals was not developed. Thus, at the autopsy several piglets' corpses had the signs of mycoplasma, that made it difficult to diagnose. The E. coli, S. pneumonia, and P. multocida bacteria were also isolated from the pigs' corpses. Each of these microorganisms provides specific pathological changes in the piglets' organs. Thus, it is difficult to perform the differential diagnosis. Samples of feed were parallely tested for the damage by microscopic fungi and bacteria. Fecal masses were examined for the intensity of helminthic and coccidiosis invasion. Therefore, we recommended the farm keepers to do mandatory vaccination of pregnant sows with an inactivated vaccine, the use of which provides passive protection of the offspring against viral transmissible gastroenteritis. If transmissive gastroenteritis of the pigs is detected in the farm, swine cannot be vaccinated against other diseases, but it is necessary to carry out symptomatic treatment for the destroying of secondary microflora in order to reduce the economic losses in the farm.