Bovine TB Control Evolves
By Catherine Cluett Pactol
Agriculture, health and wildlife officials visited Molokai two weeks ago to educate residents and answer questions about the ongoing bovine tuberculosis (bTB) outbreak on Molokai. Together, they discussed the impacts of the disease, what has been done and what’s ahead regarding control, legislation and community action.
The source of the 2021 outbreak that has swept through Molokai populations of cattle and pigs is still under investigation but genomic testing shows that all of the infected herds are related to a Molokai strain tracing back to feral pigs on the island’s east end.
Dr. Isaac Maeda, Hawaii Dept. of Agriculture state veterinarian, said so far, six herds of cattle and pigs have tested positive in the recent outbreak.
Testing and/or depopulation has been completed for most herds in west and central Molokai already, with only a few animals in central Molokai and a couple of herds on the east end still remaining to be tested, according to Maeda. Officials are working with affected ranchers and farmers to create herd plans, with most already completed, he added. State agencies are also formulating an evolving control plan to present to the U.S. Dept. of Agriculture (USDA).
More than 200 animals have been depopulated so far, Maeda estimated.
Though bTB cases in farm animals are on the way to being contained, many questions remain.
Maeda stressed that one of the biggest unknowns is where the disease is being harbored, because after historic outbreaks on Molokai, bTB went undetected for more than 20 years, then resurfaced again, with genomic sequencing pointing to disease strains originating on Molokai.
“From a livestock situation, we do have a handle on it, but from an island-wide standpoint, it’s probably going to be years [for disease eradication],” said Maeda. “Hopefully [we’ll get to a point that we won’t have to] deal with problems in animals and people but unless we can figure out where and how it’s being maintained, it’s difficult to give an exact prediction [of how long it can last]. We know we can get rid of it from a livestock perspective. The question is, where is it elsewhere?”
To help answer that question, officials are launching wildlife surveillance and testing on Molokai.
John Medeiros, biologist with the Department of Land and Natural Resources’ Division of Forestry and Wildlife, said DLNR’s role is to assist in surveillance of deer populations, and staff on Molokai have already received training to begin taking samples soon.
“These samples will be submitted to the USDA and they’ll put it into the labs for further testing. At this time, we will only be taking samples from selected wildlife control permits applicants that we met with…” said Medeiros. “We will not take samples currently from hunters. We encourage hunters when they do hunt, please use proper personal protective equipment, use masks and disposable gloves, and safety glasses when handling raw meat.”
To assist with ongoing management, Sen. Lynn DeCoite introduced legislation that she said will provide an initial $.5 million in funding for one full time veterinary medical officer for Molokai, one full time livestock inspector dedicated to the island, and acquisition of land for the construction of a portable field office and one vehicle.
Though officials expressed concern over the health risks of hunters handling or retaining portions of potentially infected deer for sampling, residents pointed out that hunters will continue to hunt and would be a good resource for sample collection.
“As a community, we want to figure out how we can be more offensive rather than defensive,” said Barbara Kalipi, who also served as the meeting’s facilitator. “We eat a lot of deer, it’s part of food on the table…. We have really smart people in our community and I’m hoping in your discussions there’s a way to have more brainstorming to figure out a way to be helpful,” she told officials. “I realize there’s a question about risk, but they’re at risk anyway because they’re going to keep hunting.”
Molokai’s state DOA Livestock Inspector Gene Ross Davis said he has been working one on one with hunters to educate them and inspect suspect infections in deer. Hunters who find diseased animals can call him at (808) 852-8185 and he may be able to assist in collecting samples.
Though surveillance data has yet to be completed, Maeda said it’s unlikely that many deer are infected on Molokai.
“I don’t want to instill fear in people about deer especially because it is something people do, they hunt, it’s subsistence,” he said. “Actually, in the state over the years, the number of deer that were found infected has only been like six, and this is after thousands of carcasses have been inspected… It’s not likely highly infected.”
At the May 25 meeting held at Mitchell Pauole Center, public health nurses offered on-site TB skin testing for community members.
Officials say the risk of residents contracting bTB is very low unless you have close contact with diseased animals.
“If you’re just living on Molokai but not around infected animals, you don’t have to worry,” Dr. Glenn Wasserman, M.D. DOH Chief of Communicable Disease and Public Health Nursing Division.
He recommended slaughterhouse workers, ranchers and hunters should be tested.
Wasserman said bovine TB cases in humans are uncommon compared to the regular, human strain of tuberculosis.
“In the past 15 years, the DOH typically has 100 cases of active cases of human TB in Hawaii each year,” he said. “In that entire 15 years, we’ve noted only two cases of bovine tuberculosis [in humans].”
But because of the current bTB outbreak, Wasserman said there may be more asymptomatic early cases in people. Like animals, people often do not show signs of the disease until the infection is advanced; infected cattle are frequently only detected by skin testing or at slaughter.
To schedule a TB skin test on Molokai, contact the Molokai DOH office at 808-553-7880.
Bovine TB can be spread to people by consuming unpasteurized milk, eating infected meat that isn’t cooked thoroughly, inhaling air from an infected person or animal, or by handling infected meat.
Beef, pork and venison produced on Molokai remains safe to eat, however, as meat from the Molokai Livestock Cooperative slaughterhouse is inspected by a USDA certified inspector. Officials advise hunters not to harvest meat from a carcass in poor condition or if lesions are detected.
For information on identifying bTB for hunters as well as a general fact sheet on the disease for the Molokai community, visit hdoa.hawaii.gov/ai/ldc/ and click on the labeled links.