Maui spraying A Bishop Museum entomologist helping the state identify the culprit in Maui's dengue outbreak says the Asian tiger mosquito, Aedes albopictus, is "guilty until proven innocent."
complicates ID
of dengue bug
The chief suspect, the Asian
tiger mosquito, is now harder
to find -- but that is goodDenge fever teleconference set for Wednesday
By Helen Altonn
haltonn@starbulletin.comEvidence is leaning toward the albopictus species, commonly known as the "forest day mosquito," said Neal Evenhuis, chairman of the museum's Natural Sciences Department.
But state vector control crews have done such a good job getting rid of mosquitoes in East Maui, where confirmed cases are concentrated, that it is difficult to find any carrying the virus, Evenhuis said.
State epidemiologist Paul Effler was happy to hear that, adding that he also is encouraged that many blood samples sent to the U.S. Centers for Disease Control's dengue lab in Puerto Rico have tested negative.
"But we need to be concerned about new infections confirmed and what that means for control efforts," he said. "We need to get rid of mosquitoes. Sooner or later, it will get wetter. ... Winter is coming; rain is coming. Now is the time to do the right thing."Meanwhile, health officials are trying to determine the source of Oahu's only confirmed case -- a Kaneohe resident who had not traveled off the island, Effler said.
On Maui, sprayings have helped control the mosquito population. That also has had an effect on the investigation.
"That means we can't go to back yards and find out what was biting," said Evenhuis, who, during his 26 years at Bishop Museum, studied cannibal mosquitoes and biocontrol for nine years. "If they really knocked it down, we don't really know what the vector is."
The scientists not only wanted to confirm that the Asian tiger mosquito was the vector, or transmitter, but to make sure a new species has not sneaked into the state, Evenhuis said.
"It's hard to believe in 50 years we haven't had dengue," Evenhuis said. "The reason is, the tiger species isn't a good vector. We had a hunch maybe it wasn't the true vector, and we still don't know."
Although a tiger mosquito was picked up in the Nahiku area, "As a scientist, I could argue it is never conclusive unless we dissect them and find the virus in it," Evenhuis said.
Dengue fever was last in Hawaii during World War II when the epidemic was spread by Aedes aegypti, the mosquito involved in epidemics now flaring across the Pacific and Southeast Asia, Evenhuis said.
The tiger mosquito was here then but was not dominant.
When the government wiped out most of the aegypti, albopictus took its place, Evenhuis said. But it is not a good harbor for viruses, which is why Hawaii has been disease-free so many years, he said.
Mosquitoes transmit the disease from person to person by biting. And when people live close together, even a bad vector, like the Asian tiger, is able to spread the virus, Evenhuis said.
The Hana outbreak occurred after a hula halau went to Tahiti and members returned with the illness, he said.
"But that's an advantage for us because, again, it is not a good vector," he said. "If it is knocked down in the Hana area, there is a pretty good chance of making this thing come to a halt."
Evenhuis also is optimistic about confining the disease to Maui, which has 45 of the total 48 confirmed cases, because it is moving slowly, unlike Tahiti where it was rapidly spread by Aedes aegypti.
Evenhuis said he has asked the Health Department's Vector Control Division to do some mosquito surveys, and the CDC has sent an entomologist here for research.
"We're trying to have a coordinated effort so we could help them some way," he said. "One of the bad parts of any collection is, you want to collect all interesting things. With mosquitoes you just slap them and don't bring them back to the lab."
Nonetheless, the Bishop Museum has more than 400,000 mosquitoes from throughout the Pacific among its collections of 14 million insect specimens.
The historical collections date to 1892 with Aedes aegypti recorded in the Waianae mountains, Evenhuis said. The tiger mosquito probably was introduced in the 1870s or 1880s because both species were here in the 1890s, he said.
According to anecdotal stories, he said the Culex night-biting mosquito was the first mosquito in Hawaii, arriving in 1826 in Lahaina. And it is still around.
"If you hear something in your room at night, it's probably that."
An interactive video teleconference on Hawaii's dengue fever outbreak will be held Wednesday in Honolulu and Bangkok. Denge fever teleconference
set for WednesdayStar-Bulletin staff
The Honolulu symposium, limited to 44 participants, will be from 4 to 7 p.m. at the Tripler Army Medical Center, Uphouse Learning Center, 4th Floor, G-Wing (mountainside).
The U.S. Medical Command, the Center of Excellence for Disaster Management and Humanitarian Response and the Pacific Telehealth and Telemedicine Hui are sponsoring the "Global Emerging Infectious Disease Symposium."
The Bangkok event will be held simultaneously, from 9 a.m. to noon Thursday, Thailand time, at the Phramongkutklao Hospital.
Those attending will have an opportunity to talk to dengue experts making presentations at both sites.
A unique high-speed link with video and audio transmission will be used for the teleconference. It is part of a larger project known as THAI-HI: Thailand-Hawaii Assessment of Interactive Healthcare Initiation. The project is funded by the Pacific Telehealth and Telemedicine Hui.
Topics covered will include an overview of the Hawaii outbreak, clinical syndromes, cutaneous manifestations, diagnostic tests, treatment protocols, epidemiological assessment, vector control and vaccine development.
Speakers in Honolulu will be from Tripler, the University of Hawaii John A. Burns School of Medicine, state Department of Health's Division of Communicable Disease and Center of Excellence for Disaster Management and Humanitarian Response.
In Bangkok, speakers will be from the Phramongkutklao Hospital, Armed Forces Research Institute of Medical Sciences and Mahidol University, Faculty of Tropical Medicine.
Pre-register by fax at 808-433-1555. Because of enhanced security, Hawaii participants should allow extra time to drive into Tripler and park.