New Zealand Reports First Case of HPAI
by Jennifer Shike, Bovine Veterinarian
Biosecurity New Zealand has placed strict movement controls on a commercial rural Otago egg farm, the Ministry for Primary Industries reports, after testing confirmed a highly pathogenic strain of avian influenza (HPAI) in chickens that has likely developed from interactions with local waterfowl and wild birds.
“Tests from the Mainland Poultry managed farm have identified a high pathogenic H7N6 subtype of avian influenza. While it is not the H5N1 type circulating among wildlife around the world that has caused concern, we are taking the find seriously,” Biosecurity New Zealand deputy director-general Stuart Anderson, said in the release.
Testing shows it is unrelated to a H7 strain that was identified in Australia earlier this year. Experts believe this case may have occurred as part of a spillover event, where foraging laying hens were exposed to a low pathogenic virus from wild waterfowl.
“Low pathogenic viruses are present in wild birds here, especially waterfowl like ducks, geese, and swans, and the virus can mutate on interaction with chickens,” Anderson said. “It is important to note that the strain found on this farm is not a wildlife-adapted strain like H5N1, so we believe it is unlikely to be transmitted to mammals.”
The report says there have been no reports of other ill or dead birds on other poultry farms. There are no human health or food safety concerns, so it is safe to consume thoroughly cooked egg and poultry products, the release said.
Quick action had been taken in cooperation with Mainland Poultry and a restricted place notice was issued, Anderson explained in the release. “Test results late last night confirmed the strain, but we already had restrictions in place and expert biosecurity staff on site, with more arriving today. Mainland Poultry took the right steps by reporting ill birds in one shed on the property and locking that building down as testing continued,” he said. “We will move quickly, with Mainland Poultry, to depopulate birds on the remote property, and we’ve placed a tenkilometer buffer zone around it alongside the restrictions preventing movement of animals, equipment, and feed. We aim to stamp this out like we did with infectious bursal viral disease that affected chickens in 2019.”
John McKay, chief executive of Mainland Poultry, manages the free-range farm. He says the farm is committed to taking quick action. “We have been preparing for an event like this for some time, knowing that low pathogenic avian influenza is already present in New Zealand wild birds,” McKay said in the release. “Fortunately, this is not the H5N1 type that has caused concern for wildlife in other parts of the world. International experience with avian influenza has shown us this particular strain (H7N6) can be eradicated quickly and successfully.”
Biosecurity New Zealand will work closely with industry partners to limit possible impacts to trade.
Protecting the Herd from New World Screwworm
by Kim Brackett, NCBA Policy Division Chair
Every cattle producer knows that pests are a challenge to our operation, but some pests are far more dangerous than others. One of the new threats to our herd comes from the New World screwworm, which is currently advancing through Central America into southern Mexico and could soon be at our border.
The New World screwworm (NWS) is a fly that has a particularly gory way of harming our cattle. Female NWS flies lay their eggs in open wounds or body orifices and when the larvae hatch, they burrow deep into the skin like a screw driving into wood. These maggots feed on cattle’s tissue, causing larger wounds as they go.
NWS flies and their burrowing larvae cause extensive damage to cattle and infestations can spread rapidly. In 1966, we eradicated screwworms in the United States through sterile insect technique. The US Department of Agriculture (USDA) bred sterile male NWS flies that mated with wild female screwworms and failed to produce offspring. Eventually, these flies died out in the US and now they only exist in a handful of South American countries.
Unfortunately, these flesh-eating flies are now on the march north. Since 2022, USDA’s Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of New World screwworms in Costa Rica, Nicaragua, Honduras, and Guatemala. Just last month, screwworms were discovered in southern Mexico, which raised red flags for us at the National Cattlemen’s Beef Association (NCBA).
Once in Mexico, it is easy for screwworms to travel north and appear on our southern border. These flies can hitch a ride on people, livestock, or wild animals, not to mention the thousands of vehicles and cargo containers traveling through Mexico to the United States.
We know how devastating it would be if the New World screwworm returned to the United States, which is why NCBA is raising the alarm now. First, we are communicating with Mexico’s cattle industry leaders so they can begin the process of screening for these flies and push for eradication efforts in their country. We are also supporting USDA-APHIS to bolster the use of sterile flies. Recently, we have been concerned that our existing sterile flies might not be getting the job done, and NCBA is pushing for more flies and better flies that will help us beat back these pests.
Although we haven’t confirmed any New World screwworms in the United States, we need you to be on high alert. New World screwworms have orange eyes, a metallic blue or green body, and three dark stripes across their backs. If you see any suspicious flies, please alert your local veterinarian, Extension agent, or contact USDA-APHIS Veterinary Services.
Please also pay close attention to your cattle and watch for any open wounds or sores. If cattle exhibit irritated behavior, head shaking, you notice the smell of decaying flesh or spot maggots in a wound, seek treatment from a veterinarian immediately. Proper wound treatment and prevention is the best way to protect your farm or ranch from a screwworm infestation. NCBA is also sharing the latest updates through our website. We encourage you to visit www.ncba.org/NWS for all the latest information on how to protect your operation.
NCBA is always on the clock to protect the US cattle industry from threats like New World screwworm. Through your vigilance and NCBA’s advocacy, we can protect the United States cattle herd. .