Summary of the 2001–02 Pennsylvania H7N2 Low Pathogenicity Avian Influenza Outbreak in Meat Type Chickens

Abstract

H7N2 low-pathogenicity (LP) avian influenza (AI) virus was isolated from chickens submitted to the Pennsylvania Animal Diagnostic Laboratory System on December 4 and 5, 2001. The cases were from two broiler breeder flocks in central Pennsylvania that had clinical signs of an acute, rapidly spreading respiratory disease. Seroconversion to AI virus was detected on follow-up sampling. Subsequently, H7N2 LPAI virus was isolated in five different broiler flock cases submitted between December 14, 2001, and January 3, 2002. Clinical signs and lesions in broilers, when present, were compatible with multicausal respiratory disease. With the exception of one broiler flock that was processed, birds from all of the virus positive flocks were euthanatized in-house within 11 days of the original case submission date. Increased surveillance of poultry flocks within 10-mile radius zones centered at the foci of the positive farms continued until March 1, 2002. No additional cases were detected.

Geostatistical visualisation and spatial statistics for evaluation of the dispersion of epidemic highly pathogenic avian influenza subtype H5N1

“…Whilst outbreaks of influenza in domestic poultry continue to be blamed on contact with free-range and wild birds, based on the circumstantial evidence of co-location of wild birds and domestic poultry in time and space [7], illegal movements of poultry and other avian species have been documented as contributing to H5N1 spread in several instances [20,24]. Live bird markets have also been the presumed source of avian influenza outbreaks in domestic poultry, notably in the United States [6,10,16,18,22] and in Asia [24].…”

“…Traditional husbandry practices in China and Southeast Asia, which favour commingling of multiple avian and mammalian species -as well as the popularity of live bird markets -may have contributed to the maintenance of the H5N1 virus strain [24]. In other regions of the world, HPAI outbreaks in commercial poultry have been traced to live bird markets [6,10,16].…”

Emergence and Genetic Variation of Neuraminidase Stalk Deletions in Avian Influenza Viruses

“…However, AIVs can cause outbreaks in poultry [4], [5], [6], [7], [8]. In some instances, AIV strains from poultry hosts have increased pathogenicity for poultry species [9], [10], and have acquired an ability to infect mammalian hosts [11], [12], [13], and/or have caused fatal infections in humans [14], [15].…”

Contribution of Company Affiliation and Social Contacts to Risk Estimates of Between-Farm Transmission of Avian Influenza

“…A LPAI H7N2 virus infected 47 broiler flocks in Pennsylvania from 1996–1998 and seven flocks in 2001 and 2002, resulting in the culling of three million birds and losses exceeding $4 million [11], [12]. In 2002, LPAI H7N2 appeared in Virginia, spreading to 197 turkey and broiler farms and resulting in the depopulation of 4.7 million birds [13], and resurfaced in live markets and broiler facilities in the Northeast and Mid-Atlantic again in 2004. An LPAI H5N2 virus resulted in culling over 75,000 turkeys in the Shenandoah Valley in 2007; detections of LPAI H7N9 and LPAI H7N3 led to the culling of 116,000 turkeys and broiler breeders in Nebraska and Arkansas that same year.…”