Epidemiological description of an avian infectious bronchitis outbreak in Costa Rica, associated with an IBV...

Avian infectious bronchitis (IB) is a disease that has severe economic effects in poultry production worldwide. This condition is caused by the avian infectious bronchitis virus (IBV). In Costa Rica, the virus was reported for the first time in the 1990s, becoming an important infectious agent associated with respiratory disease outbreaks in the country. This study describes an IB outbreak occurred in Costa Rica during 2016-2019. The IB outbreak occurred in the province of Alajuela, place that holds most of the poultry production IBV was also detected in the neighboring provinces of Puntarenas and Guanacaste. Samples were collected from birds exhibiting IB-related symptoms and IBV infection was molecularly diagnosed by RT-PCR and DNA sequencing. Diagnosis resulted in 76% (52/68) of the samples positive for IBV in 2016, 71% (24/34) in 2017, 56% (14/25) in 2018 and 42% (8/19) in 2019. The main affected farms affected were large farms (85% of positive cases), farms dedicated to meat production (82%), and young birds, broilers (1 day to 6 weeks) and pullets (1 day to 18 weeks) (81%). Respiratory symptoms and carcass condemnations in broilers were reported during the entire period of this study, while gastrointestinal symptoms, high mortality, or low quality of the eggs were not reported regularly. Moreover, 22% of the positive cases showed secondary infections by other pathogens. Sequencing results identified IBV GA13-like variants in samples during the 2016-2017 period. In 2017, a 4/91 live-attenuated vaccine variant was introduced, which was later detected in birds exhibiting symptoms during 2018 and 2019. The biosecurity tool did not reveal IB risk or gaps in biosecurity at positive farms.

The online version contains supplementary material available at 10.1007/s13337-025-00945-7.