Mexico: SENASICA Announces Two More Outbreaks Of HPAI H7N3

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Mexico has a long history of sporadic outbreaks of both LPAI (low pathogenic) and HPAI (Highly Pathogenic)  H5 & H7 outbreaks, going back more than two decades. Large outbreaks have been fairly rare the past few years, but in 2012-2013 (see OIE: Mexico Reports HPAI H7N3 In Two States), H7N3 forced the culling of more than 22 million birds.

Roughly 6 weeks ago, in Mexico: SENASICA Announces Two Outbreaks Of HPAI H7N3 - their first avian flu report since notifying the OIE of the detection of subclinical H7N3 at a single farm in Jalisco State in April of 2017.

Yesterday (h/t Tetano & Pathfinder on FluTrackers), Mexico's SENASICA (National Health Service, Food Safety and Food Quality) announced two new outbreaks of HPAI H7N3 discovered at small non-commercial poultry holdings in Guanajuato and Querétaro.

First the (translated) statement, and then I'll return with a bit more.

SENASICA reported to the OIE, and immediate closure of two outbreaks of avian influenza AH7N3

After confirming in their laboratories presenc ia the virus, he ordered the depopulation of two farms in the states of Guanajuato and Queretaro.

Author: National Health Service, Food Safety and Quality
Publication date : April 21, 2018

The National Service of Health, Food Safety and Quality (SENASICA) reported to the World Organization for Animal Health (OIE by its French acronym) the finding of avian influenza AH7N3 highly pathogenic in two properties, one located in the municipality of Irapuato, Guanajuato and one in Pedro Escobedo, Queretaro.

The agency reported that none of the two cases was identified on commercial farms, so they do not pose a risk in domestic poultry production, which has an inventory of more than 200 million laying hens and 300 million broilers to cycle.

After confirming the presence of the virus in official laboratories, SENASICA ordered the immediate depopulation of both properties, one located in Guanajuato, which had a population of 60 birds of combat, of which 35 died from the disease and rest was eliminated.

Moreover, the site located in Queretaro maintained a population of two thousand 604 birds of organic stance, of which 563 thousand were killed and the rest were killed.

In accordance with established procedures for such findings, official personnel conducting the monitoring of farms and properties located on the periphery of 10 kilometers and so far no health problems have been detected elsewhere.

Outbreaks of avian influenza were found thanks to the work of epidemiological surveillance carried out by the body, in order to timely detect the virus and prevent its spread to commercial poultry.

While most notorious for their ability to cause great damage in poultry flocks, avian H7 viruses have shown some propensity to infect humans as well. Beyond the obvious example of H7N9 in China:

• Mexico reported a couple of mild human H7N3 infections back in 2012 (see MMWR: Mild H7N3 Infections In Two Poultry Workers - Jalisco, Mexico), resulting in conjunctivitis without fever or respiratory symptoms. 
• In February of this year Jiangsu China Reported the 1st Novel H7N4 Human Infection, which resulted in a 3-week hospitalization for a 68 year old woman in Jiangsu Province for severe pneumonia. 
• In December of 2016, a veterinarian caring for sick cats at a NYC shelter was mildly infected (see NYC Health Dept Statement On Human H7N2 Infection).
• 3 mild cases in Italy in 2013 (see ECDC Update & Assessment: Human Infection By Avian H7N7 In Italy). 
• 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.
• 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. 
• And 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. 

With the exception of H7N9, which emerged in China in 2013, human H7 infections have generally been mild. Once regarded as a low public health risk, H7N9's recent over-achievements have put H7 viruses in a new light.

The CDC's IRAT (Influenza Risk Assessment Tool) currently tracks 14 novel viruses viewed as having at least some `pandemic potential', and of those, 4 are avian H7 viruses (2 strains of H7N9, H7N7, and H7N8).  

For now H7N3's main threat is as a poultry epizootic - and with the spring migration well underway - poultry interests along the northbound flyways in Mexico, the United States, and Canada should pay special attention to their biosecurity over the next few weeks.