State readying war on mice

By Timothy Hurley
Advertiser Maui County Bureau

The state Health Department is stepping up its battle against Hawai'i's burgeoning mouse population with more workers, hundreds of bait traps and by working with large landowners to use more poison.

State Health Director Bruce Anderson said officials are seeing a rise in mouse trappings on O'ahu as well as on Maui, the Big Island, Kaua'i and Moloka'i. Advertiser library photo

If the Health Department wants to continue using the zinc phosphate on a large scale after 15 days, it must seek approval from the federal Environmental Protection Agency. State Health Director Bruce Anderson said he thought that would be likely.

Much of the effort will be focused initially on Kihei and Wailea on Maui, some of the areas hardest hit by the mouse problem.

Anderson said a crew of 10 to 12 people from Maui's Emergency Environmental Work Force would be pulled from dengue fever and miconia control and sent to Kihei, to set up and check hundreds of bait stations on a daily basis.

"Hopefully that should make a difference,'' said department spokeswoman Janice Okubo.

The Maui work force is the last contingent of a program established by the state Legislature primarily to battle a dengue fever outbreak.

After lawmakers declined to renew the program, Maui County allocated $100,000 to retain its work force through the end of the year.

The statewide mouse problem follows several years of drought and this year's heavy rains that caused grasses and food to grow, and the mouse population with them.

When the food supply diminished over several dry months, the rodents began scouring residential areas for food.

The Health Department urged residents last week to control mouse populations by cleaning up food sources, trapping wherever possible and using insecticides against fleas.

Trapping by State Vector Control in June indicated that field mice had increased at least fourfold in some parts of the state, including Maui, the Big Island, Kaua'i and Moloka'i.

While O'ahu has fewer of the large open lots and pasture lands where mice breed, Anderson said officials are seeing a rise in mouse trappings there as well.

But it is South Maui that appears to be taking the worst hit.

In Maui Meadows, a Kihei neighborhood on the edge of open ranch land, residents are finding mice in their pools and trapping them in their homes.

Dead mice can be seen every 30 feet or so on the streets.

"It's all anybody's talking about — the mice in Kihei. People are catching them left and right, left and right,'' said Gerri deBeer, a Kihei Realtor.

In nearby Wailea, on the night of June 13, 20 Health Department Vector Control traps caught 365 mice. Two weeks later, 666 mice were caught in the same number of traps in one night. More recent trapping figures were not available.

Trapping rates are up across the state, and Anderson said he did not see populations dropping off for at least a couple of months.

He said his department expects to receive permission from the state Department of Agriculture to spread zinc phosphate-baited oats on open fields in the next day or two. Zinc phosphate is used only in smaller box traps.

Anderson said the chemical has no secondary impacts, meaning that an owl eating a poisoned mouse will not die.

He said the department is already talking with landowners about permission to spread the baited oats on their property. In a few instances, ranchers have already removed cattle from those areas.

Health officials say control efforts are important because mice and the fleas they carry can spread diseases such as leptospirosis, murine typhus and salmonella.

Health officials especially are keeping an eye on murine typhus and its possible link to the mouse problem, Anderson said. Seven of eight cases this year have occurred on Maui — six of them with ties to Kihei.

The Health Department sent out a notice to physicians advising them to be on the watch for the disease, which is spread by fleas.