Other Laboratory Programs

SURVEILLANCE FOR OTHER MOSQUITO-BORNE DISEASES

Malaria is an infectious disease caused by a parasite and transmitted to people primarily by Anopheline mosquitoes. In Sacramento and Yolo counties, there are two species of mosquitoes that can transmit the malaria parasite: Anopheles freeborni (the Western Malaria Mosquito) and Anopheles punctipennis (the Woodland Malaria Mosquito). We receive malaria case reports from the Sacramento County and Yolo County Health and Human Services Departments. Our laboratory responds to the reports by trapping mosquitoes in the area surrounding the malaria case. The mosquitoes are returned to the laboratory for identification, and all female Anopheline mosquitoes are tested for malaria parasites.

Dengue is another disease carried by mosquitoes. It is caused by a virus and transmitted to people by two mosquito species which are not commonly found or established in our region. Our District receives reports of Dengue cases every year, usually from people who traveled abroad. We respond to those by setting traps and collecting mosquitoes from around their residences for testing.

Dirofilaria immitis is a filarial nematode that causes heartworm disease. It is vectored in this region primarily by the tree-hole mosquito, Aedes sierrensis. Field technicians inspect and treat all known sources of this species, but they may be difficult to find, inspect and treat. Our laboratory conducts surveillance for the adult tree-hole mosquitoes in its routine trapping. In addition, we have a monthly Heartworm Program, which consists of contacting veterinary clinics and hospitals in Sacramento and Yolo Counties about heartworm tests preformed and positive cases found each month. Positive cases are matched to their addresses and that information in conjunction with tree-hole mosquito locations help determine the areas of higher risk for heartworm transmission.

For more information on our heartworm surveillance program, please contact us atten.etibehtthgifnull@mrowtraeh.

PESTICIDE RESISTANCE MANAGEMENT
Pesticide resistance is of great concern in control programs. Pesticide resistance may occur when the same compound is used routinely. It is ideal to rotate pesticides with different modes of action so that mosquito populations do not become resistant. When resistance develops in a mosquito population, previous treatments which had controlled the mosquitoes are no longer effective. Therefore, it is critical to monitor local mosquito populations to be sure we are effectively controlling them. To monitor pesticide resistance, we perform numerous tests using both larvae and adults.

TICKS AND LYME DISEASE
Ticks transmit Lyme disease. The bacterium that causes Lyme disease is called Borrelia burgdorferi. The primary vector for Lyme disease in Sacramento and Yolo counties is the western black-legged tick, Ixodes pacificus. Every year, our laboratory collects tick specimens from seven locations from November through May using a technique called tick flagging where ticks attach to a flannel sheet which is dragged along the side of a trail. All ticks collected are processed and tested for Borrelia burgdorferi.

Did you know?
An obvious way to distinguish a female mosquito from a male mosquito is by the hair on their antennae. A male mosquito has very hairy, bushy antennae.