Mosquito Borne Diseases - Napa County Mosquito Abatement District


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	MOSQUITO-BORNE DISEASES West Nile Virus · West Nile Virus is the number one mosquito transmitted disease in the United States. · Disease caused by a mosquito transmitted virus. · Incubation: period 5 to 15 days. · Symptoms: Many people show little or no symptoms. Those that become ill can have fever, headache, nausea, body aches and swollen lymph nodes. 1 in 150 infect persons may require hospitalization. · Susceptibility: The elderly are the most susceptible to the virus. · Diagnosis: By physician using acute phase serum or cerebral spinal fluid. · Treatment: There is no specific treatment for infection. Supportive care is important (contacting your physician, fluids, electrolytes, managing fever, etc.) · Mosquito vectors: efficient vectors are: Little House Mosquito (Culex pipiens) Foul Water Mosquito (Culex stigmatosoma) Tule Mosquito (Culex erythrothorax) Encephalitis Mosquito (Culex tarsalis) Other species of California mosquitoes are being tested to determine their ability to transmit this disease. Known Occurrences in Napa County West Nile Virus was first detected in Napa County birds in the summer of 2004. This virus has been found every year since and is expected to be present in the County for many years to come. Our first human case was diagnosed in 2006 with the second and last case in 2007. Coordinated surveillance work will continue with neighboring Mosquito Abatement District’s and the California Department of Heath Services, testing birds and mosquito populations for the presence of this virus. For more information about this disease go to the Centers for Disease Control or the California West Nile Virus page. back to top Malaria · Disease caused by parasites belonging to the genus Plasmodium · Incubation: period varies from 12 to 30 days depending on the species of plasmodium responsible for the infection. Plasmodium vivax is the most prevalent and typically takes about 14 days. · Symptoms: Typical symptoms are violent fever lasting six to eight hours that recur every two to three days (chills and fever cycles) Severe chills and shivering lasting approximately an hour, followed by high fever for one to two hours more. Left untreated anemia and enlargement of the spleen develop. · Diagnosis: with blood test by physician. · Treatment: with anti-malaria drugs. · Mosquito vector: Anopheline mosquitoes: Western Malaria Mosquito (Anopheles freeborni) Woodland Malaria Mosquito (Anopheles punctipennis) Known Occurrences in Napa County No locally contracted cases of malaria have occurred in Napa County in more than 65 years. The last imported case occurred in 1998. For more information about this disease go to the Centers for Disease Control. back to top Saint Louis Encephalitis · Disease caused by a mosquito transmitted virus. · Incubation: period usually 5-10 days. · Symptoms: Fever, severe headache, nausea, and stiff neck. Severe cases may include vomiting, disorientation and paralysis. · Diagnosis: By physician using acute phase serum or cerebral spinal fluid. · Treatment: There is no specific treatment for infection. Supportive care is important (contacting your physician, fluids, electrolytes, managing fever, etc.). · Mosquito vector: Encephalitis Mosquito (Culex tarsalis) Little House Mosquito (Culex pipiens) Southern House Mosquito (Culex pipiens quinquefasciatus) Known Occurrences in Napa County No confirmed human cases reported in Napa County. For more information about this disease go to the Centers for Disease Control. back to top Western Equine Encephalitis · Disease caused by a mosquito transmitted virus. · Incubation: period usually 5-10 days. · Symptoms: May have flu-like symptoms including fever, headache and lethargy. Severe cases may include vomiting, anorexia, disorientation and paralysis. · Diagnosis: By physician using acute phase serum or cerebral spinal fluid. · Treatment: There is no specific treatment for infection. Supportive care is important (contacting your physician, fluids, electrolytes, managing fever, etc.). · Mosquito vector: Encephalitis Mosquito (Culex tarsalis) Known Occurrences in Napa County No confirmed human cases reported in Napa County. The virus for Western Equine Encephalitis was last detected in the Calistoga area in 1996. For more information about this disease go to the Centers for Disease Control. back to top Dog Heartworm Disease · Disease caused by a mosquito transmitted filarial worm that primarily affects dogs. · Incubation: period - none. 70 to 90 days for the worms to become mature in dogs. · Symptoms: Long term symptoms: chronic cough that is aggravated by exercise, unusual tiring after exercise, and shortness of breath. · Diagnosis: By veterinarian. · Treatment: With anti-filarial drugs. · Mosquito vector: Western Treehole Mosquito (Aedes sierrensis) Known Occurrences in Napa County Dog Heartworm is prevalent in Napa County. No current statistics are readily available concerning the number of new cases diagnosed each year in dogs. For more information about this disease go to the Centers for Disease Control. back to top