Public Health officials have confirmed that a second Guam resident has acquired dengue infection locally.
According to a press release from the Guam Homeland Security/Office of Civil Defense, this latest case involves a man who was seen at the Guam Memorial Hospital emergency room. He resides on Swamp Road in Dededo.
Containment efforts include the immediate canvassing and notification of potentially affected areas, insecticide spraying, and ongoing surveillance as required by Public Health’s response plan, the press release stated.
“The best preventive measure for all Guam residents is to eliminate mosquito breeding sites, which are primarily artificial containers that hold water where mosquitoes lay eggs. Dengue fever is transmitted to humans by the bite of an infected mosquito and cannot spread directly from person to person,” the release said.
Guam's first locally acquired case of dengue fever in 75 years was confirmed last week.
The dengue virus is transmitted to humans via mosquito bite. The species Aedes aegypti serves as the primary transmitter, or vector, of the virus.
This species has not been seen on Guam for decades but, according to Linda DeNorcey, the director of the Department of Public Health and Social Services, traps are being used to confirm the mosquito’s presence on island.
So far, it hasn’t been detected, DeNorcey said.
Asian tiger mosquito on Guam can also transmit dengue
The Aedes aegypti mosquito was eliminated from the island in response to an epidemic of dengue fever following the American reoccupation of Guam in 1944.
The species was reintroduced to Guam in 1970 but, by that time, the Asian tiger mosquito had occupied the aegypti's ecological niche. The tiger mosquito, however, can also transmit the disease.
Last week's discovery of a locally acquired dengue case triggered Public Health’s Arboviral Disease Response Plan, which includes fumigation and other forms of mosquito control.
“We don’t know how many mosquitoes are infected. That’s why we’re examining all the mosquitoes when they get trapped,” DeNorcey said.
Public Health has also requested assistance from the U.S. Centers for Disease Control and Prevention to identify, through genotyping, the type of dengue being carried by infected mosquitoes.
“We can see what virus is in the mosquito and we can compare that virus with the human sample virus,” DeNorcey said. “We can also, through the U.S. CDC support system, be able to have them identify if the virus in the mosquito is the same that we see in other mosquitoes in the outbreaks occurring right around us.”
While the type of dengue in the intial locally acquired case was identified as DENV 3 – the same type found in the Philippines, Yap, Palau and the Marshall Islands – DeNorcey said Public Health wants to perform confirmatory testing. U.S. CDC has agreed to help with genotyping, she added.
Ann Pobutsky, a territorial epidemiologist with the health department, previously stated it's not necessary to put dengue patients under quarantine, as the virus does not spread between humans directly.
Principal symptoms of dengue fever are high fever, severe headache, pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding usually around the nose or gums.
But infected people can also be asymptomatic, Pobutsky said.
"They could be infectious and not even know it. So that's the other problem with dengue fever," she added.
Given the outbreaks in the surrounding areas, it was "almost inevitable" that dengue would be reintroduced to Guam, Pobutsky said.
Homes in Mangilao being sprayed with pesticide
The first locally acquired case led to pesticide spraying at a middle school and elementary school in Ordot-Chalan Pago. Public Health has also identified about 82 homes for spraying in Mangilao.
DeNorcey said the department is getting permission from homeowners to spray.
Meanwhile, Gov. Lou Leon Guerrero, on Friday, signed an executive order declaring a state of emergency and allocating $250,000 to Public Health.