Prospective study of avian influenza H9 infection in commercial poultry farms of Punjab Province and Islamabad Capital Territory, Pakistan

Abstract

A prospective study was conducted from November 2013 to February 2014 to estimate the spatial clustering; cumulative incidence and risk factors associated with avian influenza (AI) subtype H9 infection on commercial poultry farms of Pakistan. A total of 400 farms were enrolled and followed during the study period. Among these, 109 farms submitted samples suspected for AI to the laboratory, and only 47 farms were confirmed positive by hemagglutinin inhibition (HI) test. Data was collected from these 109 farms about their demography, management, and biosecurity practices. The cumulative incidence of H9N2 was 11.75 % (95 % confidence interval (CI) 8.76-15.23). The highest number of cases (40.42 %) was reported in January. One most likely cluster (p = 0.009, radius = 4.61 km) occurred in the Kasur district. Multivariable logistic regression analyses showed that the presence of wild birds on the farms (odds ratio (OR) = 16.18; 95 % CI 3.94-66.45) was independently associated with H9N2 infection. Cleaning of cages before delivery on farm (OR = 0.16; 95 % CI = 0.06-0.47), presence of a footbath at the entrance of farm (OR = 0.24; 95 % CI 0.08-0.79), and changing of gloves (OR = 0.33; 95 % CI 0.11-0.99) were protective factors against H9N2 infection. Reducing the exposure to risk factors and adapting biosecurity measures may reduce the risk of AI H9N2 infection on commercial poultry farms in Pakistan.

Active Surveillance and Risk Assessment of Avian Influenza Virus Subtype H9 from Non-Vaccinated Commercial Broilers of Pakistan

“…The absence of footbath at the entrance of the shed or the absence of rubber boots for visitors can create a breach in biosecurity and increases the risk of infection. These factors were proven to be the deterrent of AI in the current study and also endorsed by other researchers (Woo & Park, 2008;Biswas et al, 2009;Abbas et al, 2012;Chaudhry et al, 2015;Chaudhry et al, 2017;Gompo et al, 2019). Three factors significantly enhanced seropositivity in the birds in the current the study.…”

A Global Perspective on H9N2 Avian Influenza Virus

“…In recent surveys in Vietnam, prevalence of the virus exceeded 3.5% in chickens in LBMs [61,62]; in various Chinese provinces prevalence was found to be upwards of 10% [63][64][65][66]. Several separate studies have shown that the prevalence in Bangladesh and Pakistan of H9 viruses in chickens at LBMs and farms was almost 10% [30,[67][68][69]. Another recent study has shown prevalence of upwards of 10% at LBMs in Egypt [70].…”

A Global Perspective on H9N2 Avian Influenza Virus

“…In recent surveys in Vietnam, prevalence of the virus exceeded 3.5% in chickens in LBMs [71,72] and in various Chinese provinces, prevalence was found to be upwards of 10% [73,74,75,76]. Several separate studies have shown that the prevalence in Bangladesh and Pakistan of H9 viruses in chickens at LBMs and farms was almost 10% [35,77,78,79]. Another recent study has shown prevalence of upwards of 10% at LBMs in Egypt.…”