With the confirmation of avian influenza in the southeastern United States this spring, the virus has struck the United States for the fourth year in a row.

Related: Bird flu confirmed in Tennessee chickens

Related: Bird flu in Tennessee is H7N9, but different than virus in China 

Since the first reported case in 2014, over 40 million chickens and turkeys have died or been euthanized across 15 states in the U.S.

According to the World Organization for Animal Health, 13 strains of avian influenza were detected in 77 countries between January 2014 and December 2016. After the outbreak two years ago, Mexico and Canada introduced state or regional bans on U.S. broiler exports, and China imposed a national ban. With news of the recent outbreak, Hong Kong, South Korea and Taiwan have all halted import of U.S. poultry.

"Even one infected chicken house could have a global impact," said Mark Leggett, president of the Mississippi Poultry Association. "One of the worst impacts from the bird flu in the U.S. is the impact on global trade. We export a large percentage of poultry products to other countries around the world."

The USDA's National Veterinary Services Laboratories (NVSL) cautioned the public that the strain of avian influenza experienced in Tennessee is not the same as the H7N9 virus that has impacted poultry and infected humans in China and across Asia. 

"Fortunately, there have been no reported cases of strains of avian influenza affecting humans in the U.S. as a result of the recent outbreak. In fact, all poultry flocks in the United States are tested prior to processing to make sure they are healthy and free of any virus," Leggett continued. "American consumers have a high degree of confidence in the safety of our food supply, and that confidence is well placed." 

When outbreaks of avian influenza occur, state and federal agencies, as well as industry representatives and wildlife experts, work together quickly to review and modify biosecurity methods that are in place.

"Within every state that we operate, Texas, Georgia, Mississippi and North Carolina, there are both state and federal plans in place in the event of a reported infection," said Dr. Phil Stayer, Corporate Veterinarian for Sanderson Farms, the country's third largest poultry producer. "All state plans must meet the federal minimum standard; however, Sanderson Farms goes well above and beyond the federal minimum standard."

Many companies within the industry have taken great strides to ensure the strictest biosecurity methods and precautions are in place to protect flocks from infectious diseases.

"Previously, we thought the virus was primarily spread by coming up the driveway, transmitted from farm-to-farm by service vehicles and on equipment. Now, we realize it's spread as waterfowl fly overhead, meaning it can easily be picked up by simply walking across the yard through duck droppings," said Stayer. "This means we have had to change our entire mindset from farm-by-farm, to house-by-house. All of which means much tighter security."

Understanding how the virus is transmitted has played a major role in establishing biosecurity measures and developing response plans.

"This particular strain of bird flu affects all bird species who contract the virus and most birds that get it will get sick and die. However, waterfowl like geese and ducks don't necessarily get sick and can carry the virus for longer periods of time and from place to place as they migrate," said Dr. Kenneth Angel with USDA's Veterinary Services for Louisiana and Mississippi.

"Other birds can get the virus, but they don't spread the virus long distances because they get too sick to fly, while some are able to spread the virus on their feet or feathers without actually becoming sick.

"We know that waterfowl are the main carriers of the virus, so that is where we are concentrating our efforts. We also know the virus does not survive well in hot temperatures, which accounts for why we do not see large outbreaks during the summer months in the southern portion of the U.S."

Houston Havens, Mississippi Department of Wildlife Fisheries and Parks Waterfowl Program Leader, said, "The South is just starting to see some of the early migrants. Migration varies by species and other variables. Weather will play a large role in the intensity of migration. Birds can tolerate the cold, but long periods of extended cold weather up north, and snow that covers food and other resources, will cue up more birds to head south to overwinter."

According to the CDC, "humans can be infected with avian and other zoonotic influenza viruses, such as avian influenza virus subtypes A(H5N1), A(H7N9), and A(H9N2) but infections are rare and acquired through direct contact with infected animals or contaminated environments, but do not result in efficient transmission of these viruses between people. There is no evidence that avian influenza viruses can infect humans through properly cooked food." State and federal ag officials say the strains of bird flu that have sickened the Tennessee chickens do not pose a threat to the food supply.

Related: Poultry industry tightens biosecurity after bird flu reported in U.S.

In Georgia, the state veterinarian has suspended all poultry exhibitions, swaps and meets, shows or sales at festivals, flea markets or auctions in the state of Georgia until further notice. This temporary suspension is in response to the recent confirmations of avian influenza in Tennessee, Alabama and Kentucky and prohibits the concentration, collection, or assembly of poultry and poultry products of all types from one or more premises for purposes of sale, exhibition, show, swap or meet. 

“It is crucial that we all take extra precautions during this high alert situation to protect the state of Georgia from this devastating virus,” State Veterinarian Dr. Robert Cobb said. “The best way to do that is to stay vigilant maintaining our biosecurity measures and to avoid the unnecessary transport and comingling of birds.” 

The suspension does not restrict importation of poultry or poultry products provided all Georgia import requirements are met prior to importation. The suspension does not restrict out–of–state export of poultry and poultry products. All exports must meet the requirements of the state or country of destination. The suspension does not affect private sales of poultry and poultry products. Shipments of eggs or baby chicks from National Poultry Improvement Plan (NPIP) Avian Influenza (AI) Clean facilities directly to approved Georgia facilities for sale to the public are not affected by this suspension. Eggs and baby chicks offered for sale that do not come from NPIP AI Clean facilities to the point of sale and/or eggs and baby chicks that move from an NPIP AI Clean facility directly to an unapproved facility and then are offered for resale are suspended temporarily.

Poultry contributes $25.9 billion to Georgia’s economy and accounts for 104 thousand jobs in the state.

Related: Possible bird flu investigated in Alabama 

Source: Georgia Department of Agriculture, Sanderson Farms