Bovine TB Found on Molokai

By Catherine Cluett Pactol

Twenty-five years after a bovine tuberculosis (bTB) outbreak on Molokai caused the culling of all the island’s cattle, a cow infected with the disease was reported by the Hawaii Dept. of Agriculture last Friday. The infected cow was originally from a beef cattle herd in Ho`olehua and was temporarily pastured in Mapulehu on the east end because of the ongoing drought, the HDOA reported.

Bovine tuberculosis, Mycobacterium bovis, is a contagious and infectious disease of animals, usually carried by cows, that can also infect humans. There have been sporadic outbreaks on Molokai in cattle herds since the 1940s, especially on the east end, but this is the first detected case in Hawaii since a Molokai outbreak in 1997.

Officials have been testing cattle herds annually for bTB as well as monitoring and testing wildlife turned in by hunters.

“The recently infected cow was one of 30 in the herd that were tested by a veterinary medical officer from HDOA’s Animal Industry Division on June 22,” a DOA release stated. “The herd is currently isolated and under HDOA quarantine in Ho`olehua. HDOA is working with U.S. Department of Agriculture (USDA) to develop a clean-up plan that will include the depopulation of the infected herd with indemnity being paid to its owner.”

The rest of the herd tested negative, but as a precaution, a decision was made to remove the entire herd to minimize exposure to other Molokai cattle. Other herds in the area or that may have been exposed will be tested to make sure the infection hasn’t spread.

“While the detection of bovine tuberculosis has only been confirmed in one animal to date, it is the foremost priority for the department to isolate and control this disease before it can spread to other cattle herds on the island,” said Phyllis Shimabukuro-Geiser, chairperson of the Hawaii Board of Agriculture. “Of all people, Molokai ranchers understand the importance of containing this disease and we appreciate their continued cooperation and assistance.”

In 1985, HDOA made the decision to depopulate all cattle on Molokai in an effort to eradicate bTB and more than 9,000 cattle were removed from Molokai, according to the DOA. After that, the state received “bovine tuberculosis free” status from USDA in 1993, which allowed the interstate movement without bTB restrictions.

That status was suspended in 1997 when a cow on Molokai was found to be infected. The cow was believed to be infected by feral pigs carrying the disease. The herd was culled and Hawaii was again declared bTB-free the following year.

HDOA’s Animal Industry Division and the USDA’s Animal, Plant Health Inspection Service, Veterinary Services have since been monitoring cattle herds and wildlife on the east end of Molokai with regular testing. Bovine TB has been found to continue in feral pigs on Molokai’s east end and the HDOA says there has been ongoing concern about the possibility of transmitting the disease back to cattle herds. In the past, bTB had also been detected in axis deer and mongoose on Molokai.

In 1917, the U.S. began a bTB eradication program in cattle, which has been highly successful. Molokai, along with parts of Michigan, have been the only areas where occasional outbreaks in wildlife and cattle herds have been found in recent years. There has been ongoing research to develop vaccines and other preventive measures that may be used in wildlife to eradicate bTB in these areas.