 Mosquitoes
and Diseases
The following links are for informational purposes only. The agencies
listed below give no direct or implied endorsement of any of the Mosquito
control products.
ENCEPHALITIS
Encephalitis in various forms such as St. Louis, Western Equine, La
Crosse, Eastern Equine, and West Nile, which was recently discovered
in the Northeast is endemic to the United States and increasing in incidence.
Although extremely rare, Eastern Equine Encephalitis has a 30% - 60%
mortality rate once contracted. Severe damage to the central nervous
system occurs in those that survive the illness.
Eastern Equine Encephalitis (EEE)
is maintained in nature through a cycle between the Culiseta melanura
mosquito and birds that live in freshwater swamps. Although Culiseta
melanura do not bite humans, some mosquitoes will "cross bite"; i.e., bite an infected bird and then bite
a human or animal (horse, emu, and other exotic birds), thereby spreading
the disease. These mosquitoes are also known as "bridge vectors".
A vector is a species that transmits a disease from one host to another.
These bridge vectors may take a meal from a bird and later take another
meal from a mammal.
Symptoms usually occur within two to ten days after being bitten by
an infected mosquito. These symptoms include high fever, stiff neck,
headache, confusion, and lethargy. Encephalitis, swelling of the brain,
is the most dangerous symptom. Rhode Island has confirmed five cases
of EEE with two deaths in the last thirteen years. The last death was
reported in 1993.
For more information on EEE:
University
of Rhode Island EEE Facts
University
of Rhode Island
State
of Connecticut Department of Public Health
For more information on St. Louis Encephalitis:
Centers
for Disease Control and Prevention
WEST NILE FEVER
Mosquitoes that carry this disease are
here now!! in South Florida. Protect yourself NOW!!
West Nile Virus symptoms include fever,
headache, nausea, vomiting, and rash, which are mild symptoms to severe
symptoms that include neck stiffness, stupor, disorientation, tremor,
coma, vision loss, and paralysis. These severe symptoms could last weeks
or could be permanent. The onset of symptoms usually begins three to
14 days after a mosquito bite. Unlike Eastern Equine Encephalitis, 80%
of the people who are infected with WNV will show no symptoms at all.
20% will show mild to serious symptoms. People who are mostly likely
to show symptoms if bitten by an infected mosquito are infants, the elderly
and people with auto-immune difficiencies.
For information on West Nile Fever see:
Centers
for Disease Control and Prevention - Questions and Answers About West
Nile Virus
Rhode
Island Department of Health
Georgia
Dept. of Agriculture
DENGUE FEVER
Dengue fever is primarily a disease of the tropics that is transmitted
by the Aedes aegypti mosquito. Aedes aegypti is
a day-biting mosquito that prefers to feed on humans. It is also transmitted
by the Aedes albopictus (also called the "tiger
mosquito"). Those infected with dengue can suffer from a spectrum
of illnesses ranging from a viral flu to severe and fatal hemorrhagic
fever (DHF).
The dengue virus is passed back and forth between mosquitoes and humans
and causes an extraordinarily painful ailment that exists in four known
strains or serotypes. Dengue is especially dangerous to children, who
generally have one infection, but if bitten again can get a more serious
infection that can lead to dengue hemorrhagic fever (DHF). DHF causes
severe internal bleeding, shock, and circulatory collapse, and is usually
fatal to children.
Until recently, dengue was relatively unknown in the Western Hemisphere.
In the 1970's, a dengue epidemic swept through Cuba and other parts of
the Caribbean. In 1981 a second strain broke out in Cuba, accompanied
by hemorrhagic fever. The second epidemic resulted in more than 300,000
hemorrhagic fever cases, and more than 1,000 deaths. Most were children.
In the summer of 1998 an epidemic broke out on the island of Barbados.
Dengue is increasingly becoming a plague of global proportions and may
soon eclipse malaria as the most significant mosquito-borne viral disease
affecting humans.
For more information on Dengue Fever:
WHO
Division of Control of Tropical Diseases
CDC
Division of Vector-Borne Infectious Diseases
MALARIA
Malaria is caused by a parasite that is transmitted from person to person
by the bite of an Anopheles mosquito. Anopheles bite during the nighttime
and are present in almost all countries in the tropics and subtropics.
Symptoms of malaria include fever, chills, headache, muscle ache, and
malaise. In its early stages it can resemble the onset of the flu. These
symptoms can develop 6-8 days after being bitten by an infected mosquito
or as late as several months after the traveler has left the area.
Malaria can sometimes be prevented by the use of antimalarial drugs
and protection against mosquito bites. Some estimates place 40% of the
world's population at risk for malaria. It is estimated that worldwide,
malaria claims over one million lives annually. (World Health Organization
1989)
For more information on malaria
World
Health Organization Control for Tropical Diseases.
YELLOW FEVER
Yellow fever is a disease caused by the bite of the Aedes aegypti mosquito.
It does not occur in the U.S. but is common in parts of Africa and South
America. The symptoms of yellow fever include fever, chills, headache,
backache, nausea, and vomiting; jaundice can also occur. More serious
cases may affect the blood, liver, and kidneys. The disease can be fatal.
The disease is spread when an infected mosquito bites a person with
yellow fever and then transmits it by biting another person.
There is no specific treatment for yellow fever, other than to relieve
the symptoms. Once a person has had yellow fever, they are immune to
further infection. The best way to prevent the disease is through vaccination
and mosquito control.
For more information on yellow fever:
World
Health Organization Fact Sheet
|