The highly pathogenic avian influenza virus that was first identified in the US in December 2014, has spread from wild birds and backyard flocks to chicken and turkey commercial flocks in Arkansas, California, Iowa, Idaho, Kansas, Minnesota, Missouri, Montana, North Dakota, Nevada, Oregon, Utah, South Dakota, Washington, Wisconsin and Wyoming, as reported by USDA.  Part of the response to these outbreaks includes the humane euthanasia of birds in the infected flocks.  So far, more than 7.3 million birds have been euthanized.

USDA provides comprehensive information about the outbreak on its website, including the history of similar outbreaks in the United States.

USDA has experience responding to highly pathogenic avian influenza in U.S. poultry. Before these current outbreaks, there were only three high path AI outbreaks in commercial poultry in U.S. history – in 1924, 1983 and 2004. No significant human illness resulted from these outbreaks.

The CDC explains the potential for human infection from this virus:

No human infections with these viruses have been detected at this time, however similar viruses have infected people in other countries and caused serious illness and death in some cases. While the public health risk posed by these domestic HPAI outbreaks is considered low at this time, it is possible that human infections with these viruses may occur.

People working with poultry flocks and responding to these outbreaks are at the highest risk of infection, since

[m]ost human infections with avian influenza viruses have occurred after close and prolonged contact with infected birds or the excretions/secretions of infected birds (e.g., droppings, oral fluids). CDC has posted guidance for clinicians and public health professionals, and is working with state health departments and animal health colleagues to minimize public health risk.

As reported by Reuters, State health officials in Minnesota, where 46 flocks have tested positive for the virus, have been

expediting prescriptions for the antiviral drug Tamiflu for farm workers and others who have been in direct contact with infected flocks . . .  follow[ing] recommendations from the U.S. Centers for Disease Control and Prevention (CDC).

Several states, including Wisconsin and Minnesota have declared a state of emergency.

State and federal animal health officials have worked closely with poultry farmers for decades developing plans to respond to outbreaks involving highly contagious diseases including highly pathogenic avian influenza. A coordinated response to this outbreak, described by USDA, requires intense cooperation to implement the following steps:

Quarantine – restricting movement of poultry and poultry-moving equipment into and out of the control area;

Eradicate – humanely euthanizing the affected flock(s);

Monitor region – testing wild and domestic birds in a broad area around the quarantine area;

Disinfect – kills the virus in the affected flock locations; and

Test – confirming that the poultry farm is AI virus-free.

The fact that the virus has continued to spread, despite these efforts, is proof that biosecurity plans must be narrowly tailored for the sectors they are intended to protect, and should be rigorously implemented.

But even the best biosecurity plans cannot prevent all outbreaks, especially when infectious diseases are spread by wild animals.

My thoughts are with the farmers and our animal health first responders battling to protect flocks and squelch the spread of this virus.