Last Friday, in Mexico: H7 Reported In Chiapas Nature Preserve, Nearby Zoo Closed, we saw media reports of a the third outbreak of HPAI H7 in southern Mexico in a month. Today the OIE has confirmed this report, and has identified the virus as HPAI H7N3 – the same virus ravaged the Mexican poultry industry in 2012-13.
Source of the outbreak(s) or origin of infection
- Unknown or inconclusive
Endemic wild birds were reported having been found dead in a nature reserve called “The Zapotal”; the reserve is in the State of Chiapas, consists of 100 hectares of semi-humid forest, with several species of sapotas, and shows a wide variety of native wildlife of this State. It has about 220 animal species in their natural environments and 154 species living freely in the reserve, of which 62 species of birds. During the initial investigation, three highly pathogenic avian influenza virus of H7N3 subtype were isolated with an intravenous pathogenicity index of 2.91 and 2.99. A 10 km focal and perifocal zone was established and no evidence of infection was found in commercial poultry. Under the national epidemiological surveillance program, a state active epidemiological surveillance program is on-going for 100% of the commercial poultry and, through a statistical sample size, in backyard poultry, based on serological, virological and molecular testing; no evidence of infection was found in commercial poultry or in backyard poultry. The affected species are Ortalis vetula and Turdus grayi. The epidemiological investigation continues.
For those who - like me - are ornithologically challenged, the two birds affected are the Clay-colored Thrush (Turdus grayi) and the plain Chachalaca (Ortalis vetula), a large bird in the family Cracidae which ranges from Southern Texas to Costa Rica.