Monday, March 12, 2018

OIE Notification: LPAI H7N1 In Texas

Hopkins County, Tx - Credit Wikipedia


Since Friday there have been vague, unconfirmed rumors of an LPAI H7 outbreak in Texas, which seemed to be confirmed this morning when Japan's Ministry of Agriculture posted a notice announcing a ban on importing Texas poultry.
In the past hour the OIE has posted an official notification, identifying LPAI H7N1 in a commercial broiler breeder flock in Hopkins County, Tx. 
This comes less than a week after LPAI H7N1 was reported in the Midwest (see CIDRAP's Low-path H7N1 detected at Missouri turkey farm). 

First the OIE notification, then I'll return with a bit more.

Epidemiological comments
As part of routine, pre-slaughter testing and surveillance for H5/H7 avian influenza, H7N1 low pathogenic avian influenza (LPAI) was detected in a commercial broiler breeder flock based upon H7 PCR and antibody to H7 and N1. Partial HA sequencing determined the H7 to be a low pathogenic virus of North American wild bird lineage. Further characterization is pending virus recovery. The flock exhibited a slight increase in mortality and a decrease in egg production. Depopulation of the premises is underway. The USDA Animal Plant Health Inspection Service (APHIS) and the Texas Animal Health Commission are conducting a comprehensive epidemiological investigation of this incident and have implemented enhanced surveillance and testing within 10km of this finding.

There are two broad categories of avian influenza; LPAI (Low Pathogenic Avian Influenza) and HPAI (Highly Pathogenic Avian Influenza).
  • LPAI viruses are quite common in wild birds, cause little illness, and only rarely death.  They are not considered to pose a serious threat to public health, although minor human infections have been reported. The concern is (particularly with H5 & H7 strains) that LPAI viruses have the potential to mutate into HPAI strains.
  • HPAI viruses are more dangerous, can produce high morbidity and mortality in wild birds and poultry, and can sometimes infect humans with serious result. The type of bird flu scientists have been watching closely for the past decade has been HPAI H5N1 (and to a lesser extent HPAI H7s & H9s).
Before the middle of the last decade, there was no uniform requirement to report or track LPAI infections.  That changed in 2006 when the OIE made reporting of LPAI H5 & H7 viruses mandatory.

With HPAI H7N3 recently reported in Mexico, two widely separated (by 300 miles) LPAI H7N1 outbreaks in the US in the last week, and the northbound spring bird migration underway, it is not an altogether bad idea for North American poultry producers to review their biosecurity procedures.

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