The Heat Is Online

Hawaii Drought-Rain Cycle Boosts Mouse Population

Mice boom in Hawaii during weather roller-coaster,
Aug 2, 2002

HONOLULU (AP) -- State health officials are asking residents to do what they can to help control a booming mouse population on the Big Island, Maui and some areas of Kauai.

Vector control officers are reporting four times as many mice as they usually see over the summer, State Health Director Bruce Anderson said Tuesday.

"We've come out of a period of extended drought and with the heavy rains we're seeing a lot more grass growing in the fields, pasture lands and other areas where mice breed," Anderson said. "Mice eat the grass seed and have been proliferating for months now.

"As the weather is now getting hot and drier, there's less grass seed growing and mice are now coming from the mountains into populated areas."

He did not have exact figures for the state or individual islands, but said anecdotal figures indicate the boom in the mouse population.

For example, Environmental Health Services Division Chief Jerry Haruno said officers on Maui say traps have caught as many as 110 mice over the past four to six months. A typical number is about 20 mice by this time of year, he said.

Areas that have seen the largest increases include Kihei, Kula and Lahaina on Maui; Waikoloa, Kawaihae and South Kohala on the Big Island; and residential areas of Waimea on Kauai.

Oahu has been mostly unaffected because it lacks breeding grounds such as large, open lots and pasture lands on other islands, Anderson said.

Control efforts are important because mice -- and the fleas they carry -- can spread diseases including leptospirosis, murine typhus and salmonella, Anderson said.

Although there has been no increase in the number of cases of those diseases, Anderson said he wants people to be aware of the potential problem.

"We are concerned that of the mice continue to proliferate in these areas there is the potential for significant outbreaks," he said, adding that the state is increasing its monitoring and control efforts.

He urged residents to control the mice population by cleaning up food sources, trapping the rodents where possible and using insecticides against fleas.

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