#18,480
While we tend to refer to H5N1 clade 2.3.4.4b as if it were a single entity, it is actually a a blanket term that covers scores of similar - but genetically distinct - genotypes, all of which continue to evolve at different rates around the globe.
Even within a single genotype - like the B3.13 `bovine' strain - there can be significant differences, including mutations that may increase virulence, or transmissibility, or both.
In North America alone, more than 100 genotypes have been identified over the past 3 years, with new ones expected to emerge over time. So far in 2024, three new reassortments of note have emerged:
- B3.13 aka the `bovine' strain affecting dairy cattle in at least 16 states and infecting dozens of humans
- D1.1 a wild bird/poultry strain which has spilled over into > a dozen people in Washington State and a teenager in British Columbia
- D1.2 a wild bird/poultry strain which recently detected in poultry and 2 pigs in Oregon
In the 3 years prior to the emergence of these new genotypes, the United States only reported 1 H5N1 infection in a poultry culler in 2022. Since March, we've seen nearly 60 human confirmed infections, and it is likely many others have gone undetected.
Although most of this avian flu activity has been focused in the western states (California, Oregon, Washington State), over the past few weeks we've begun to see reports more from further east, with major outbreaks in Iowa, South Dakota, and Minnesota.
In addition, over the past two days two states further down the Mississippi Flyway (Missouri & Louisiana) have reported significant die offs of waterfowl, a species which generally tolerates H5N1 infection pretty well, but can often be vulnerable to new genotypes.
Highly Pathogenic Avian Influenza Causing Mortality in Wild Birds in Louisiana, LDWF Announces
DECEMBER 10 2024
H5N1 Highly Pathogenic Avian Influenza (HPAI) is again causing mortalities in wild birds in Louisiana, the Louisiana Department of Wildlife and Fisheries (LDWF) announced. This year’s fall migrations have created a resurgence of HPAI-induced waterfowl disease in Louisiana.
Many different species of wild birds can be infected with HPAI. Geese and other waterfowl are particularly susceptible to HPAI. Many wild birds recover from infection and develop immunity to a particular strain of AI, but others may exhibit neurological symptoms, which ultimately lead to the death of the bird. Scavenging raptors, including vultures, are also susceptible to the disease.
Although public health officials consider this strain of HPAI to be of minimal threat to humans, sick birds should not be handled. Additionally, as this disease is highly contagious to other wild birds and domestic poultry, sick birds should not be comingled with other birds.
Mammals are, for the most part, resistant to H5N1 HPAI but rare fatal infections have been documented in dogs, cats, foxes, black bears and even dolphins. It should be noted that while many waterfowl hunting dogs contact birds with HPAI, no dog infections have been reported in Louisiana. Contact between pets and birds showing neurologic signs should be avoided.
Wildlife rehabilitators should be careful not to bring potentially HPAI-infected birds into their rehabilitation facilities to prevent introduction and spread of the disease within the facility. Clothing and other objects, or even seemingly healthy waterfowl, which may have come in contact with the disease should be washed thoroughly and kept away from other birds, especially domestic poultry.
Once again, sick birds should not be handled and no bird exhibiting signs of disease or found dead should be utilized for human consumption.
Sick or dead birds should be reported to regional LDWF offices. The contact information for these offices is as follows: Hammond Office, 985-543-4777; Lake Charles Office, 337-491-2575; Lafayette Office, 337-262-2080; Minden Office, 318-371-3050; Monroe Office, 318-343-4044; Pineville Office, 318-487-5885.
And there's this, from the Missouri Department of Conservation, which reports `. . . numerous reports of sick and dead waterfowl across the state'.
MDC encourages public to use caution amidst suspected avian influenza outbreak
JEFFERSON CITY, Mo. -- The Missouri Department of Conservation (MDC) is monitoring reports of sick and dead waterfowl, such as geese and ducks, across the state. The Department is actively collecting birds to determine the cause of illness but suspects highly pathogenic avian influenza (HPAI) to be the cause. Other states, including Kansas and Iowa, are experiencing similar occurrences.
Avian influenza, commonly referred to as bird flu, spreads as birds along the North American flyways intermingle with infected birds from Europe and Asia. The viruses are transmitted from bird to bird through fecal droppings, saliva, and nasal discharges. There is a risk for spillover from wild birds into domestic poultry and then back again from poultry to wild birds, resulting in further spread.
Though HPAI does not present an immediate public health concern, MDC recommends the following:
- Do not touch dead geese, waterfowl, or other bird species.
- Report any sightings of dead geese to MDC online at http://short.mdc.mo.gov/4KD
- Ensure that pets do not come into contact with dead animals to help prevent the spread of disease.
Due to ongoing waterfowl hunting seasons, waterfowl hunters should dress game birds in the field whenever possible or at a location away from poultry or other birds. Hunters should also properly dispose of harvest waste by placing the remains in trash bags and disposing of them through trash collection or a permitted landfill. Bald eagles and other raptors are particularly susceptible to avian influenza. This simple action could help prevent bald eagle and other raptor mortalities.
- If you have inadvertently come into contact with a dead goose, wash your hands thoroughly and contact a healthcare professional if you experience any unusual symptoms.
Hunters should also be aware it is possible to transport avian influenza viruses on boats, waders, or other equipment, especially if it isn’t dry before moving it from one site to another. Allowing hunting equipment to dry between outings will reduce this chance.
Avian influenza does not present an immediate public health concern, though on rare occasions it has infected humans and other animals. It is safe to eat poultry and wild game as normal cooking temperatures are hot enough to kill the virus if present. Meat should be cooked to an internal temperature of 165 degrees Fahrenheit.
More information can be found on the Missouri Department of Agriculture website at https://agriculture.mo.gov/avian-influenza.php.
It is not entirely clear what genotype(s) are spreading through the central United States, but D1.x is a likely suspect. As a new genotype, it might be expected to produce additional mortality in waterfowl.
Regardless, there is a high degree of H5N1 virus in the environment, and that appears to be spreading both east and south. Eastern states that have not yet been severely impacted this fall may see their threat level grow over the coming weeks.
This should be a safety concern not only to poultry owners, but to anyone who hunts, or has pets that roam outdoors, or who engages in wildlife or bird rescue. While these advisories seem to focus on contact with `dead or sick' birds, healthy-looking birds can carry, and shed, the virus as well.
Although public health officials continue to stress the risk of H5 infection to the general public is very low, a month ago the CDC issued Updated Advice To The Public On HPAI H5N1, which offers some very specific advice for protecting yourself from the virus.
