It appears that the dreaded H5 avian influenza has made its way to Hawaii island.
The state Department of Health on Tuesday said H5 avian influenza was detected in a sample collected from the Hilo Wastewater Treatment Plant on Hawaii island on Dec. 2. It is the first detection of the bird flu virus on Hawaii island, but has not yet been confirmed to be highly pathogenic avian influenza.
“This is the first detection of bird flu on a neighbor island and indicates an H5 type of bird flu virus was present,” said DOH in a news release. “Wastewater testing cannot determine if the detection is specifically the (HPAI) H5N1 subtype of bird flu virus which was recently found on Oahu.”
The announcement comes about a month after the first detection of H5 in wastewater on Oahu on Nov. 12 which was followed by confirmation of HPAI in birds.
Testing for the H5 virus in wastewater, which is collected before it’s treated, provides a signal that animals or humans in the area may be infected with the virus. But current testing methods can only detect the presence of the H5 virus, without differentiating between different strains.
A sample collected Nov. 7 from the municipal Wahiawa wastewater treatment plant tested positive for H5 on Nov. 12, the same day a backyard flock of birds was reported sick.
A national lab on Nov. 15 confirmed HPAI in the flock, later identified as rescued pet ducks and geese at Susie’s Duck Sanctuary in Wahiawa. Some 70 birds died or were euthanized at the site.
The U.S. Fish and Wildlife Service also confirmed HPAI in a wild duck — that exhibited no symptoms — from the James Campbell National Wildlife Refuge in Kahuku. A swab was taken from the duck on Nov. 1, and confirmed by the lab on Nov. 25.
Officials have confirmed the virus strain for the infected waterfowl on Oahu to be the A3 genotype, which is associated with migratory birds and different from the one infecting dairy cows on the U.S. mainland.
Health officials say while the risk to the public remains low, HPAI can cause severe illness with a high mortality rate among certain bird populations such as poultry.
DOH urged commercial poultry producers and residents with backyard flocks to increase biosecurity measures and warned it also can infect dairy cows.
Conservationists, meanwhile, have been keeping a watchful eye on HPAI, which has infected U.S. wild birds and commercial poultry since January 2022.
They are concerned for Hawaii’s native waterbirds and wetland birds, which are at highest risk.
Hawaii island is home to a number of poultry farms, as well as endangered native birds such as nene, and Hawaiian ducks and coots that live at Waiakea Pond in Hilo.
The state Department of Land and Natural Resources said it is monitoring bird and wildlife populations for signs of avian influenza.
“Currently there is no evidence of the disease on DLNR lands statewide or in native bird populations,” said DLNR in a statement. “While there is no way to prevent the spread, DLNR is working with the Department of Health and the Department of Agriculture on both monitoring and response plans.”
Reports of avian flu cases are being directed to HDOA, which said it has fielded a higher volume of neighbor isle calls lately, but no reports of unusual poultry mortality events on Hawaii island in recent weeks.
“HDOA will continue to assess situations as they arise and conduct disease investigations based on the evaluation by the veterinary staff,” said the department in an email.
The U.S. Centers for Disease Control and Prevention conducts routine wastewater monitoring by collecting samples from plants across the nation and testing them for viruses such as COVID-19, influenza and RSV.
Wastewater monitoring serves as an early detection system for infectious disease outbreaks and measures community-level trends from pieces of virus or bacteria shed in waste, which can be positive regardless of whether carriers have symptoms or not.
CDC can track the presence and concentration levels of a virus in wastewater, but can not determine its source.
