Eco-friendly options favored in dengue fever battle
| • | Special: Dengue fever: health crisis in the making |
By Yasmin Anwar
Advertiser Staff Writer
Take heart, all those opposed to DDT:
Anything goes in Hawai'i's battle against dengue fever, which has generated a bizarre arsenal of environmentally friendly mosquito artillery that includes larvae-gulping guppies.
And although vector control officials yesterday noted a sharp decline in orders to spray areas near suspected dengue fever cases — a drop from 15 a day to just two — program director Ken Hall warned that it's too soon "to let down our guard."
Public health officials had no new reports of confirmed dengue cases yesterday, leaving the statewide number of people who have been infected by the mosquito-borne disease at 48.
Only one more person, a La'ie resident, tested positive in preliminary screenings. However, the outbreak has spurred a rush on mosquito killers.
Around the state, the usual foggers and bug zappers are selling fast. But anecdotal evidence shows homeowners are also in the market for new, and in some cases, costly ways to keep their mosquito populations down — particularly in ponds, ditches, drains and other water sources near their homes.
Some swear by Mosquito Dunks, which float like doughnuts on ponds and emit a biological mosquito larvacide that kills mosquito eggs before they hatch.
Others are willing to fork out more than $700 for a Mosquito Magnet, which lures the critters with plumes of carbon dioxide, heat, moisture and octenol and then sucks them into a net where they dry up and die. Gaspro, which carries the product, has sold out and is expecting a new shipment next week.
Fish food
Then there are those who have had huge success with mosquito fish.
Richard Melton of Kailua learned how to use guppies against mosquitoes during a trip to Bali, Indonesia, and has since cut down drastically on the mosquito population around his home.
Like many Balinese villagers, Melton has placed large ceramic pots of water with guppies on his porch and lanai. The mosquitoes lay eggs in the pots, and the eggs are then eaten by the fish.
"We used to have a terrible mosquito problem, and now they've pretty much disappeared," said Melton, who works at the Hawaiian multi-service organization Alu Like Inc.
Melton is not the only one using the guppy offensive. Guava Kai Plantation on Kaua'i's North Shore has long used Gambusia affinis (also known as mosquito fish and medaka) in its drains and ditches to control the mosquito population.
Jack Gushiken, manager of the 400-acre guava ranch, says they need to use environmentally friendly methods to safeguard their guava crops.
Mosquito fish can eat up to 200 mosquito larvae a day. However, they also eat amphibian larvae and so some entomologists advise against using them in creeks and other watering holes where frogs and newts dwell.
Hall, program manager for the state's vector control branch, says whatever works and doesn't harm people and wildlife in the process is fine with him. However, he does urge people to carefully follow the directions on any product.
The dengue virus is transmitted by Aedes mosquitoes, which commonly breed in water puddles, flower pots and old tires.
In Hawai'i, the dengue virus is believed to be carried by the Asian tiger mosquito, Aedes albopictus. The vector has stripes and usually bites during the day.
Painful illness
Victims usually suffer high fever, rash, muscle aches, headaches and eye pain. Severe cases of the disease can develop into dengue hemorrhagic fever, which has a fatality rate of 5 percent.
The best way to eradicate the vector and the larvae is to remove potential breeding places such as small containers that collect standing water.
Vector control crews have been spraying Permanone, a larvacide made up of petroleum distillates.
City officials say they will continue to pick up rubbish in special sweeps to help eliminate breeding grounds for mosquitoes.
City Environmental Services Deputy Director Frank Doyle said Mayor Jeremy Harris extended the special pick-ups through this Saturday. As of last Saturday, the city had picked up about 1,000 tons of rubbish in the special sweeps.
And Doyle said extended pick-ups can still be made when there's a need.
"We're going to continue sweeping the areas until this is over," he said.
Staff writer Robbie Dingeman contributed to this report.
