Mosquito Borne Illnesses
Diseases transmitted by mosquitoes include: Malaria, Dengue, West Nile Virus, Chikungunya, Yellow Fever, Zika Virus, and other diseases. Scroll down to find information on prevention, West Nile Virus, and Zika Virus.
Protection from Mosquitoes and the Diseases they Carry
During the summer, mosquitoes can develop in any standing water that lasts more than a week. You can begin protecting your family from mosquitoes by reducing the amount of standing water available for mosquito breeding around your home:
- Dispose of discarded tires, cans, plastic containers, ceramic pots or other unused similar water-holding containers that have accumulated on your property.
- At least once per week, empty standing water from containers on your property, such as tire swings, or bird baths.
- Clean clogged roof gutters, particularly if the leaves from surrounding trees have a tendency to plug up the drains. Flooded roof gutters are easily overlooked but can produce hundreds of mosquitoes each season.
- Turn over wheelbarrows and plastic wading pools when not in use.
- Store boats covered or upside down, or remove rainwater weekly.
- Clean and chlorinate swimming pools that are not being used. A swimming pool that is left untended by a family that goes on vacation for a month can produce enough mosquitoes to result in neighborhood-wide complaints. Be aware that mosquitoes may breed in the water that collects on swimming pool covers.
- Keep drains, ditches and culverts free of grass clippings, weeds and trash so water will drain properly.
- Fill in low areas on your property to eliminate standing water. Ponds or streams where fish are present or the water is disturbed by current or wave action do not produce many mosquitoes.
Should we stay indoors?
It is not necessary to limit outdoor activities unless there is evidence of mosquito-borne disease in your area. However, you can and should try to reduce the risk of being bitten by mosquitoes.
- Minimize time spent outdoors between dusk and dawn when mosquitoes are most active.
- Be sure door and window screens are tight-fitting and in good repair.
- Wear shoes, socks, long pants and a long-sleeved shirt when outdoors for long periods of time, or when mosquitoes are most active. Clothing should be light colored and made of tightly woven materials to keep mosquitoes away from the skin.
- When it is necessary to be outdoors, apply insect repellent as indicated on the repellent label. The more DEET a product contains, the longer the repellent can protect against mosquito bites. However, concentrations higher than 50 percent do not increase the length of protection. For most situations, 10 percent to 25 percent DEET is adequate. Apply repellents to clothes whenever possible; apply sparingly to exposed skin if label permits. Consult a physician before using repellents on young children.
For more information contact the Director of Environmental Health
West Nile Virus
West Nile virus (WNV) is a potentially serious illness that flares up in North America in the summer and continues into the fall.
What Are the Symptoms of WNV?
Most people (about 4 out of 5) who are infected with WNV will not show any symptoms at all. Some people who are infected can develop a low fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
How Does West Nile Virus Spread?
Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.
How Soon Do Infected People Get Sick?
People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.
How Is WNV Infection Treated?
There is no specific treatment for WNV infection. In most cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.
What Should I Do if I Think I Have WNV?
Milder WNV illnesses usually improve on their own, and most people do not necessarily need to seek medical attention for this infection though they may choose to do so. People who develop symptoms of severe WNV illness, such as unusually severe headaches or confusion, should seek medical attention immediately. People over the age of 50 are more likely to develop serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.
Zika Virus Disease is a disease caused by the Zika Virus, which is primarily spread to people through the bite of an infected Aedes species mosquito.
What are they symptoms of Zika Virus?
- Most people infected with Zika virus won’t even know they have the disease because they won’t have symptoms. The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes). Other common symptoms include muscle pain and headache. The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week.
- See your doctor or other healthcare provider if you are pregnant and develop a fever, rash, joint pain, or red eyes within 2 weeks after traveling to a place where Zika has been reported. Be sure to tell your doctor or other healthcare provider where you traveled.
- The illness is usually mild with symptoms lasting for several days to a week.
- People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika. For this reason, many people might not realize they have been infected.
- Zika virus usually remains in the blood of an infected person for about a week but it can be found longer in some people.
- Once a person has been infected, he or she is likely to be protected from future infections.
How is Zika Virus Transmitted?
Through mosquito bites:
Zika virus is transmitted to people primarily through the bite of an infected Aedes speciies mosquito (A. aegypti and A. albopictus) These are the same mosquitoes that spread dengue and chikungunya viruses.
- These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases. They prefer to bite people, and live indoors and outdoors near people.
- Mosquitoes that spread chikungunya, dengue, and Zika are aggressive daytime biters, but they can also bite at night.
- Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites.
From mother to child:
- A pregnant woman can pass Zika virus to her fetus during pregnancy. Zika is a cause of microcephaly and other severe fetal brain defects. We are studying the full range of other potential health problems that Zika virus infection during pregnancy may cause.
- A pregnant woman already infected with Zika virus can pass the virus to her fetus during the pregnancy or around the time of birth.
- To date, there are no reports of infants getting Zika virus through breastfeeding. Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where Zika virus is found.
Through Sexual Contact:
- Zika virus can be spread by a man to his sex partners.
- In known cases of sexual transmission, the men developed Zika virus symptoms. From these cases, we know the virus can be spread when the man has symptoms, before symptoms start and after symptoms resolve.
- In one case, the virus was spread a few days before symptoms developed.
- The virus is present in semen longer than in blood.
Through Blood Transfusion
- As of February, 1, 2016, there have not been any confirmed blood transfusion transmission cases in the United States.
- There have been multiple reports of blood transfusion transmission cases in Brazil. These reports are currently being investigated.
- During the French Polynesian outbreak, 2.8% of blood donors tested positive for Zika and in previous outbreaks, the virus has been found in blood donors.
What are my Risks?
- Anyone who lives in or travels to an area where Zika virus is found and has not already been infected with Zika virus can get it from mosquito bites. Once a person has been infected, he or she is likely to be protected from future infections.
How is Zika Virus Diagnosed and Treated?
- The symptoms of Zika are similar to those of dengue and chikungunya, diseases spread through the same mosquitoes that transmit Zika.
- See your doctor or other healthcare provider if you develop the symptoms described above and have visited an area where Zika is found.
- If you have recently traveled, tell your doctor or other healthcare provider when and where you traveled.
- Your doctor or other healthcare provider may order blood tests to look for Zika or other similar viruses like dengue or chikungunya.
- There is no vaccine to prevent or medicine to treat Zika virus.
- Treat the symptoms:
- Get plenty of rest.
- Drink fluids to prevent dehydration.
- Take medicine such as acetaminophen (Tylenol®) or paracetamol to reduce fever and pain.
- Do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) until dengue can be ruled out to reduce the risk of bleeding.
- If you are taking medicine for another medical condition, talk to your doctor or other healthcare provider before taking additional medication.
- If you have Zika, prevent mosquito bites for the first week of your illness.
- During the first week of infection, Zika virus can be found in the blood and passed from an infected person to a mosquito through mosquito bites.
- An infected mosquito can then spread the virus to other people.