Decreased effectiveness of vaccination against infectious bronchitis as the result of increased incidence of vesicular enteritis in broilers

The incidence of infectious bronchitis (IB) in chickens has increased in Russian Federation during 2020- 2021 despite the widespread vaccination of the susceptible poultry. The effectiveness of vaccinations against IB virus and Newcastle disease can be significantly affected by vesicular enteritis (runting stunting syndrome) accompanied by malabsorption. The study presented demonstrated that virally induced malabsorption in broilers is accompanied by the synchronous decreases in the concentrations of magnesium and zinc in blood serum. Evaluation of the effectiveness of vaccination by RT-PCR for the presence of IB viral RNA in the intestine at day 2 after the vaccination indicates a sharp decrease in the PCR prevalence in individuals with vesicular enteritis and allows for the exclusion of possible population-wide decrease in post-vaccination immunity. When considering biochemical parameters as markers of organopathologies the population-based approach to data analysis should be applied.

Study of the protective effects of virucidal drugs on the model of coronavirus pneumonia

Infectious bronchitis of chickens (IBC) is a widespread disease in the Russian Federation caused by a virus from the genus Gammacoronavirus. The pathology of the respiratory system caused by the IBV virus in chickens has many similarities with the pathology of the respiratory system caused by SARS CoV2 in humans. The efficacy of the virucidal drugs "Ecocid C", "Triviron", "Argovit" was tested on chickens infected with a tenfold dose of the vaccine based on the attenuated H120 strain against infectious bronchitis of chickens (IBV). In the experiment, the presence of inflammatory changes in the intestines, lungs and thymus was observed on day 6 after infection. The experimental groups were characterized by less pronounced inflammatory changes and a lower proportion of thymus and lung probes containing genomic IBV RNA. Since the virocidal activity of Trivirone, Ecocide C, Argovit was possible only in the intestine, then as a model of respiratory infection with COVID19, the experimental data indirectly confirm the hypothesis of the fundamental possibility of the predominant accumulation of coronaviruses in the intestine and subsequent lung damage during hematogenous redistribution of viral particles and antigens such as IBV. and other coronaviruses, including SARS CoV2. The dynamic balance between the reproduction of coronaviruses in the intestine and their elimination should be easily disturbed when the concentration of functionally active viral particles (under the action ofvirucidal agents) decreases, incl. due to the initially low concentration of coronaviruses. In terms of pharmacoprophylaxis of infectious bronchitis, it seems promising to use virucidal agents in the period preceding the formation of supply immunity. Инфекционный бронхит кур (ИБК) - широко распространенное в Российской Федерации заболевание, вызываемое вирусом из рода Gammacoronavirus. Патологии респираторной системы, вызванные вирусом ИБК у кур, имеют много общих черт с патологией респираторной системы вызванной SARS CoV2 у человека. Было проведено испытание эффективности вироцидных препаратов "Экоцид С", "Тривирон", "Арговит" на цыплятах, зараженных десятикратной дозой вакцины на основе аттенуированного штамма H120 против инфекционного бронхита кур (IBV). В эксперименте наблюдали наличие воспалительных изменений в кишечнике, легких и тимусе, на 6 день после заражения. Экспериментальные группы характеризовались менее выраженными воспалительными изменениями и меньшей удельной долей проб тимуса и легких содержащих геномную РНК IBV. Так как вироцидная активность Тривирона, Экоцида С, Арговита была возможно только в кишечнике, то в качестве модели респираторной инфекции COVID19 данные экспериментов косвенно подтверждают гипотезу о принципиальной возможности преимущественного накопления коронавирусов в кишечнике и последующем поражении легких при гематогенном перераспределении вирусных частиц и антигенов как IBV, так и других коронавирусов, включая SARS CoV2.