New Recorded Mosquito Species on Guam

For Immediate Release

August 7, 2017; 10:15am

DPHSS Release No. 2017-064

New Recorded Mosquito Species on Guam                                                                           

In an effort to prevent the introduction of new mosquito species that can transmit mosquito-borne diseases, and control those mosquitoes already found on Guam, the Division of Environmental Health (DEH) of the Department of Public Health and Social Services has been conducting mosquito surveillance by collecting adult and larval mosquitoes in various parts of the island for identification.  Utilizing its new mosquito lab in the Guam Environmental Public Health Laboratory (GEPHL), DEH’s Mosquito Surveillance and Control Program, with the assistance of an entomologist from the Zika Emergency and Preparedness Project, which was established by the efforts and funding of the Pacific Island Health Officer Association and the U.S. Centers for Disease Control and Prevention, a new previously unrecorded mosquito species has been found on island.

This newly recorded mosquito has been identified as Wyeomyia mitchellii through both morphological identification and DNA sequencing, which were facilitated by Dr. Cameron Webb and his colleagues at New South Wales Health Pathology (Sydney, Australia).  Although Wyeomyia mitchellii females obtain their blood-meals from warm-blooded animals, including humans, it is not a known vector of diseases to man.  Wy. mitchellii was first described from Jamaica, but is also native to South Florida.  This species lays its eggs in the water-filled axils of bromeliads, which is a flowering plant popular in gardens and homes.  Wy. mitchellii was first detected outside of its native range in Hawaii in the 1980s, and was subsequently recovered in Tahiti in 2007.  It is speculated that Wy. mitchellii arrived in Tahiti through illegal bromeliad imports from Hawaii.

According to Dr. Russell Campbell, agricultural entomologist with the Guam Department of Agriculture, his department inspects all legal imports of bromeliads from the Philippines and from Hawaii, but that smuggled plants hidden in containers may have previously introduced pest species on Guam.  As multiple specimens of male and female Wy. mitchellii were collected from only one location on island, it is difficult to determine both the timing of this species’ introduction, and the extent of its distribution on Guam.

The finding of this new mosquito species should be a reminder to the public that Guam is highly vulnerable to the introduction of exotic insects, including mosquito species, such as Aedes aegypti, which is an efficient vector in transmitting Dengue Fever, Zika Virus, and Chikungunya.  DEH and its partners are working to preventing the introduction and establishment of this particular mosquito and other vectors.  An outbreak of a mosquito-borne disease can have a severe impact to Guam’s healthcare system and its economy.

The public can do its part by eliminating mosquito breeding sites by removing standing water to prevent them from propagating.  Some tips include:

  • Cleaning up debris, including that which can hold water;
  • Properly disposing of loose tires;
  • Cleaning pet water dishes regularly;
  • Cleaning, emptying, and properly screening or covering containers used to store water;
  • Clearing roof gutters of debris;
  • Properly disposing all bottles, cans, buckets, and other containers that can collect water;
  • Plugging tree holes;
  • Repairing leaky outdoor faucets so as not to create standing water; and
  • Changing the water frequently in flower vases and other containers that contain water.

For any questions, please contact the Division of Environmental Health’s Mosquito Surveillance and Control Program at (671) 300-9566 or 300-9575.