While the United States and Canadian poultry industry has been busy fighting HPAI H5 avian flu viruses, in Mexico the concern (thus far) has been for outbreaks of HPAI H7.
Just shy of a month ago, we learned of two southern Mexican states – Oaxaca & Pueblo - recently hit by the H7N3 virus (see OIE: Mexico Reports HPAI H7N3 In Two States) – an avian strain which forced the culling of more than 22 million Mexican birds between 2012-13.
Beyond the tremendous economic damage to the Mexican economy, we also saw a couple of mild human infections with the virus back in 2012 (see MMWR: Mild H7N3 Infections In Two Poultry Workers - Jalisco, Mexico), resulting in conjunctivitis without fever or respiratory symptoms.
Although H7 avian viruses have had only a limited track record of causing human infection - until the H7N9 virus appeared in China just over two years ago (causing 200+ deaths) – H7 viruses were viewed as capable of only causing mild illness.
- In 2003 a large outbreak of H7N7 (89 confirmed, 1 fatality) in the Netherlands – with nearly all reported cases having very mild (often just conjunctivitis) symptoms.
- The Fraser Valley H7N3 outbreak of 2004 resulted in at least two human infections, as reported in this EID Journal report: Human Illness from Avian Influenza H7N3, British Columbia
- In 2006 1 person in the UK was confirmed to have contracted H7N3, and the following year, 4 people tested positive for H7N2 – both following local outbreaks in poultry.
- 3 mild cases in Italy in 2013 (see ECDC Update & Assessment: Human Infection By Avian H7N7 In Italy).
Except for China’s unusual H7N9 virus, most H7 avian viruses are considered really only threat to the poultry industry.
That said, H7 flu strains - like all influenza viruses - are constantly mutating and evolving. What is mild, or relatively benign today in humans, may not always remain so.
All of which brings us to a pair of media reports (hat tip Gert Van der Hoek on FluTrackers) indicating that roughly 30 grouse at a Chiapas Nature preserve have been found to be infected with H7 avian flu, and that a nearby zoo has been abruptly closed for `remodeling’ and over `animal health’ concerns.
Nevertheless, this story is being carried by multiple new agencies, and hopefully we’ll get a clarification from the Mexican authorities, or an OIE notification, in the next day or so.
Bird flu detected in 30 wild birds in Chiapas
Source Beatriz Gonzalez May 7, 2015 15:58 pm
Vigilance against bird flu (Image: SENASICA).
Mexico, DF.-In Chiapas , some 30 birds of origin wild , were eradicated by personnel of the National Health Service, Food Safety and Quality (SENASICA), because they were infected with the virus of bird flu .
SENASICA said that a fence a 10 kilometer radius of the reserve was established, and nearby farms were asked extreme security measures to prevent the spread of the virus.
Meanwhile, Tuxtla Gutierrez Zoo closed its doors as a measure of protection to species.
Burying the lede somewhat – as it doesn’t mention the H7 outbreak until the middle of the third paragraph – is this report from SDPNoticias.com.
Writing SDPnoticias.com Thu 07 May 2015 17:02
Tuxtla Gutierrez, Chiapas.- Authorities regional zoo "Miguel Alvarez del Toro" (ZooMAT) in Chiapas, announced that from 12 to 25 May this year, the space is closed to the public for reasons of remodeling, major maintenance and animal health actions.
Through a statement, the authorities unveiled that "ZooMAT is subject to a gradual transformation to optimize quality service to the public and provide greater comfort to the species housed in each of its campuses. However, work has intensified, implying the need to temporarily close its facilities not involve the safety of visitors ".
It was also reported that birds found in total freedom inside the reserve, specifically chachalacas a detected outbreak of influenza H7, so the measures of health security will be strengthened to prevent birds sheltered in enclosures exhibition at risk of being infected.
Although Mexico has been spared from dealing with the HPAI H5 virus currently affecting the United States, they may be at increased risk of seeing it next fall when the migratory birds now nestled in their northern breeding grounds head south.
That said, there is nothing that says H7 viruses couldn’t hitch a ride on a northbound bird as well.