‘Aussie Mozzie’ Discovered in Los Angeles County

September 15, 2014

Two Los Angeles County vector control districts are urging residents to continue reporting daytime biting mosquitoes after discovering a new species of mosquito in Monterey Park and Montebello.

During an expanded search this summer for the invasive Asian tiger mosquito, staff from the San Gabriel Valley Mosquito and Vector Control District (SGVMVCD) and the Greater Los Angeles County Vector Control District (GLACVCD) collected unusual specimens from a couple of homes.

After some initial research, photographs of the mosquito were sent to Dr. Cameron Webb and John Clancy with the Marie Bashir Institute of Infectious Diseases and Biosecurity at the University of Sydney, Australia and they confirmed it to be Aedes notoscriptus. The mosquito is considered a major domestic pest in all parts of Australia, and capable of transmitting several viruses (Barmah Forest and Ross River) to people, both of which are not documented in LA County. It is uncertain if Ae. notoscriptus will become a major public health risk in California, however it is an important vector of dog heartworm in Australia, and may be cause for concern in the veterinary community and for pet owners in Los Angeles County.

Dr. Webb noted, “This is one of the most widespread pest mosquitoes in Australia and, as well as being a nuisance-biting pest, has been implicated with mosquito-borne disease outbreaks in our cities.”

A Bigger Threat

With the increase in global travel and trade, and a changing local climate, both districts are deeply concerned about the continued risk of invasive species into California. “Each new introduction brings with it additional economic and public health risks,” says Kenn Fujioka, the SGVMVCD’s manager.

Vector control officials are warning residents that although Ae. notoscriptus is currently not a pressing threat, the Asian tiger mosquito (Aedes albopictus), discovered in LA County in 2011, poses a greater risk to public health. Like Asian tiger mosquitoes, Ae. notoscriptus prefer smaller containers of water in which to lay their eggs, and they bite most aggressively in the afternoon and into the evening. Both of these characteristics are different from the more common local mosquitoes in southern California.

The Asian tiger mosquito is a potential vector of debilitating diseases such as dengue and chikungunya. While these two viruses have not been transmitted locally in Los Angeles County, the presence of this mosquito poses a threat. The SGVMVCD and GLACVCD will continue to control and monitor the Asian tiger mosquito and Ae. notoscriptus. Both Districts encourage residents and businesses to call if they are getting daytime mosquito bites – indications of potentially dangerous invasive species of Aedes mosquitoes.

How it was Found

According to the experts in Australia, this represents the first ever identification of Ae. notoscriptus in North America. The initial Ae. notoscriptus was collected by the SGVMVCD during routine surveillance in June but efforts to identify the battered specimen were inconclusive.

In August, a request for assistance by a Montebello resident led to the discovery of a black-and-white striped mosquito by the GLACVCD. This specimen was intact and positively identified.

“We applaud our residents’ role in reporting mosquito problems,” said Susanne Kluh, the GLACVCD’s Director of Scientific-Technical Services. “This type of community watch behavior benefits everyone.”

During the identification process both agencies expanded surveillance and control for this new mosquito into their programs. The SGVMVCD has identified Ae. notoscriptus from three sites in Monterey Park and the GLACVCD has identified two in the city of Montebello.

To stop the spread of these invasive threats in Los Angeles County, public health officials are calling upon all residents in nearby communities to do their part by following these steps:

• CALL AND REPORT to vector control any sightings of small, black-and-white mosquitoes or if you are being bitten by mosquitoes during the day!

• Dump and drain all standing water around your home.

• Discard or put away any containers, cans, buckets, and old tires around the home.

• Empty bird baths and small fountains completely or clean them thoroughly every 3 days.

• Talk to your neighbors about mosquito breeding prevention.