Spatiotemporal and risk analysis of H5 highly pathogenic avian influenza in Vietnam, 2014–2017

Publication date: Available online 22 April 2019Source: Preventive Veterinary MedicineAuthor(s): Lam Thanh Nguyen, Mark A. Stevenson, Simon M. Firestone, Leslie D. Sims, Duc Huy Chu, Long Van Nguyen, Tien Ngoc Nguyen, Kien Trung Le, Norikazu Isoda, Keita Matsuno, Masatoshi Okamatsu, Hiroshi Kida, Yoshihiro SakodaAbstractThe aim of this study was to describe the spatiotemporal distribution of H5 HPAI outbreak reports for the period 2014–2017 and to identify factors associated with H5 HPAI outbreak reports. Throughout the study period, a total of 139 outbreaks of H5 HPAI in poultry were reported, due to either H5N1 (96 outbreaks) or H5N6 (43 outbreaks) subtype viruses. H5N1 HPAI outbreaks occurred in all areas of Vietnam while H5N6 HPAI outbreaks were only reported in the northern and central provinces. We counted the number of H5N1 and H5N6 outbreak report-positive districts per province over the four-year study period and calculated the provincial-level standardized morbidity ratio for H5N1 and H5N6 outbreak reports as the observed number of positive districts divided by the expected number. A mixed-effects, zero-inflated Poisson regression model was developed to identify risk factors for outbreak reports of each H5N1 and H5N6 subtype virus. Spatially correlated and uncorrelated random effects terms were included in this model to identify areas of the country where outbreak reports occurred after known risk factors had been accounted-for. The presence of an outbreak report ...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research