Specialists from Latin America learn of new CVM vaccine against H9N2 and the results of studies evaluating a mobile testing unit for use on the farm and in the field.

Researchers in the University of Georgia’s College of Veterinary Medicine shared recent successes in their efforts to control the spread of avian influenza with more than 250 colleagues during the 15th International Seminar on Poultry Pathology and Production.

Hosted by the CVM in Athens Aug. 18-22, the conference drew specialists in poultry medicine and production primarily from Latin America. Presenters lectured in both English and Spanish.

The event, held every four years, grew from two small courses hosted by Dr. Pedro Villegas in 1983 for Spanish colleagues. Villegas, a native of Colombia, retired from a distinguished career in the CVM, where he discovered the Villegas-Glisson/Georgia (VG/GA) strain of Newcastle disease and developed a vaccine to protect poultry.

A New Vaccine and Field Test

Daniel Perez

Villegas gave an opening welcome at this year’s conference, where Daniel Perez, the Caswell S. Eidson Chair in Poultry Medicine and Georgia Research Alliance Distinguished Investigator in the Poultry Diagnostic and Research Center, discussed a new vaccine against the low pathogenic H9N2 strain of influenza A.

Perez was elected to the National Academy of Sciences earlier this year in recognition of his distinguished and continuing achievements in original research. Membership is considered one of the highest honors a scientist can achieve.

Perez called H9N2 “the godfather of influenza viruses” because it donates genes to several flu viruses that can affect humans, including H5N1 or bird flu.

H9N2 infections are prevalent in Asia, the Middle East, and Africa, but the virus has been detected on all continents. Although low-path strains of avian flu are seldom the cause of mortality in wild and domestic birds, these viruses can lead to delayed growth, lower egg production, and poor eggshell quality. They also increase susceptibility to secondary infections with respiratory pathogens and substantial economic losses to growers.

Existing vaccines against H9 subtypes of influenza A use inactivated viruses which makes them less effective against a strain that has mutated. Perez’s laboratory at UGA developed a live attenuated vaccine that triggers an immune response but does not cause illness in the host or others. Genetic modifications also prevent it from reassorting to create a new strain. It can be administered to poultry flocks en masse, for example, through drinking water. The vaccine was announced in the August 2024 issue of npj Vaccines.

Perez also announced the development of a new field test unit for avian influenza that detected high and low path H5N1 in molecular samples from chickens and ducks. The PDRC conducted a two-phase research study assessing the effectiveness of a palm-sized mobile molecular test device made by Alveo Technologies. The unit screens for the H5, H7 and H9 influenza subtypes on the farm and in the field, giving results in 45 minutes, according to the company.

“We believe (the test unit) is quite sensitive and it … could work in the field as some kind of help to the influenza diagnosis,” Perez said.

The PDRC was not compensated for its research on the effectiveness of the device.

Wildlife and Avian Influenza

As investigators elsewhere in the college pursue a deeper understanding of the pathways of transmission, mutation and impacts of bird flu, two types of testing revealed surprising data about the infection and survival rates of wild birds and mammals exposed to influenza A along the Mississippi River corridor.

Rebecca Poulson

Rebecca Poulson, assistant professor in the Department of Population Health at the Southeastern Cooperative Wildlife Disease Study, told the conference that mammals are increasingly figuring into her studies as bird flu continues to evolve and affect new species.

“We know that mammals are being impacted terrestrially,” she said. Putting a call out to wildlife rehabilitation centers that provided swabs and serum from sick and injured animals along the corridor, Poulson’s lab learned that raccoons, foxes and skunks had antibodies to influenza.

Wild birds like eagles, hawks, vultures and owls have been hard it by highly pathogenic avian influenza viruses over the past several years in North America. Work done by Poulson’s group, with collaborators at the University of Minnesota Raptor Center, provided evidence that some of these species can survive HPAI infection and mount immune responses. There may be some resilience building in nature, which is good news, Poulson said.

Serologic sampling is providing researchers with new insight into the rates of exposure and survival among wild birds and mammals exposed to flu A viruses.

“Such serologic data allows even better context as related to exposure as it is occurring in nature,” Poulson said. Age, species, previous influenza A exposure history, and migration patterns, distance and timing all play a role in understanding the evolution of bird flu and its impact on wild animals.

“I maintain that we really cannot understand the trajectory of these highly pathogenic viruses without the really important backdrop from serology can provide when overlaid with virology and biology,” she said.