Vector-Borne & Zoonotic Diseases Program

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Northern Nevada Public Health Vector-Borne & Zoonotic Diseases Program

Vector-borne & zoonotic diseases are diseases that are transmitted between humans and other animals. Zoonotic diseases are transmitted directly between humans and other animals, whereas vector-borne diseases are transmitted by blood-feeding anthropods (such as mosquitos, ticks, and fleas). The vector-borne & zoonotic diseases program not only performs prevention measures in the community, but also receives reports of illness or animal bites and either evaluates the reports for risk or investigates confirmed illness.

The Vector-Borne Disease Prevention Program (VBDPP) is a program in the Environmental Health Services department who facilitates various services, prevention measures, and certain vector and animal removal and transportation.

If reporting a complaint, wanting a bug identified, or in need of general information about vector-borne & zoonotic diseases, prevention, and services provided by Northern Nevada Public Health, please see the Environmental Health Services Vector-Borne Disease Prevention Program.

Contact number: (775) 328-2434
E-mail: HealthEHS@nnph.org

For general information and links to associated publications, see below.

Mosquito-Borne Encephalitis Viruses

Mosquito-borne viruses that cause illness in humans and domestic animals are known as "arboviruses". There is a potential risk to humans and domestic animals in Washoe County from arboviruses, which can cause mild to serious illness. An arboviral-caused encephalitis (brain inflammation) can develop which may result in long-term disability including partial paralysis and memory loss or death.

West Nile Virus brochure

CDC – Arboviral Encephalitis

West Nile Virus Epi-News (2018)

West Nile Virus Epi-News (2023)

St. Louis Encephalitis (SLE) Epi-News

Western Equine Encephalitis Epi-News

Rabies

Rabies is a viral disease that affects the central nervous system of humans and other domestic animals. Rabies is usually spread from one animal to another (and to humans) through a bite. The virus is transmitted through the infected animal's saliva. It is always fatal in humans but can be prevented if the individual receives a series of shots after being bitten by the rabid animal. Immediate washing of a bite wound with soap and water can also play an important role in prevention of this dread disease.

Rabies vaccinations programs for dogs and cats and public education about rabies has been crucial in making this disease a rare occurrence in humans in the United States. Usually there are fewer than five human cases of rabies in the United States each year.

Rabies Brochure

Rabies information from the CDC

Rabies and Bats Fact Sheet

Hantavirus

Hantavirus pulmonary syndrome (HPS) is an infectious disease caused by a virus that can be fatal to humans. Rodents such as the white-footed deer mouse found in Washoe County spread it to people. The droppings and urine of infected mice contain virus particles which cause infection in humans after being inhaled.

Historical mouse surveys for hantavirus have been completed in Cold Springs, Silver Knolls, Caughlin Ranch Parkway, Spanish Springs, and Galena Creek Park. These surveys allowed our Program staff to determine levels of hantavirus in rodents from different areas and to make appropriate recommendations to residents to prevent illness. The average rate of infection for hantavirus in deer mouse populations in the area is about 15%, although this figure fluctuates greatly and may vary up or down in any given area at any given time. Test results have shown as low as 5% or as high as 50% of the rodents trapped testing positive for hantavirus.

CDC page on Hantavirus Pulmonary Syndrome (HPS)

Hantavirus Infection Epi-News

Lyme Disease

Lyme disease is a bacterial infection that causes skin, joint, heart, and nervous system problems. It can cause chronic, long-term illness in humans if not identified and treated early.

A tick can be easily removed by gripping it at the base of the imbedded mouthparts with a tweezers. By gently pulling, the tick will release within a few seconds. Do not use Vaseline, gasoline, alcohol, or burn the tick with a match. Do not turn the tick clockwise two times. These popular methods of removal can cause the bacteria to be expelled into the host and can increase the chance of infection. These and similar methods should never be used.

CDC - Learn about Lyme Disease

Lyme Disease Epi-News

Plague

Plague is caused by a bacterium called Yersinia pestis. The bacteria are passed between rodents through the bite of an infected flea. It can be passed to humans by a flea bite or by handling animals that have died from the disease. The disease can be fatal if it is not treated with antibiotics or if treated too late in the course of the illness. Domestic cats are particularly vulnerable to plague and often spread the disease to their owner.

There have been no human cases of plague in Washoe County for more than twenty years. However, plague does maintain a presence in wild rodent populations in the area. California ground squirrels, golden mantle ground squirrels, chipmunks, and rabbits are known to harbor plague-carrying fleas in Washoe County.

More information on plague from the CDC

Racoon Roundworm

Raccoon roundworm, known scientifically as Baylisascaris procyonis, is a parasitic infection that has gained some attention in the U.S. as a source of human disease. Although this parasite is relatively harmless to the raccoon, serious illness can occur in humans when infective eggs are accidentally ingested. Ingested eggs hatch as larvae in the small intestine, penetrate the intestinal wall and migrate to other organs such as the liver, lungs, and brain through the circulatory system. If the larvae migrate to the eye, brain, or spinal cord, there can be severe and irreversible damage including blindness, paralysis, and death.

Fortunately, the incidence of human illness in the U.S. is low (less than 30 cases have been reported). Young children are the most likely individuals to become infected as they commonly put dirt and other objects into their mouths. The CDC receives over 4,000 requests annually for laboratory testing for this parasite.

Racoon Roundworm Brochure

Zika virus

Zika virus is an emerging vector-borne disease spread primarily through the bite of infected Aedes aegypti mosquitoes. Although Aedes aegypti is not known to occur in Northern Nevada, Northern Nevada Public Health remains committed to active surveillance for this and other closely-related mosquito species in order to prevent their establishment in our region. Residents are encouraged to contact the Health District if experiencing mosquito problems at any time.

The greatest risk of contractive Zika virus for Washoe County residents is through travel to countries with active Zika transmission. It is highly recommended that travelers contact their local travel clinic or primary health care provider before and after traveling to regions reporting active Zika transmission.

Symptoms of Zika Virus may be similar to those of Dengue and Chikungunya including fever, rash, joint and muscle pain, conjunctivitis (red eyes) and headache. Because Zika virus has been linked to certain complications with pregnancy and birth defects and the potential for transmission through body fluids, it is recommended that pregnant women and their partners strictly follow the advice of their healthcare providers and to seek additional information before and after travel by either person.

Zika Virus CDC