(3) Culex. Culex mosquitoes, depending upon the species, may bite any
time of the day or night. They are commonly found in fresh or stagnant water in and
about buildings and in swamps, ditches, street gutters, cesspools, and other places
which hold water. The common house mosquitoes found in the US are members of this
group. The larvae hang at an angle in the water and the adults rest and feed parallel to
the surface as do Aedes mosquitoes (figure 5-2).
There are many diseases transmitted by mosquitoes. Some of the more
important ones are malaria, yellow fever, dengue fever, encephalitis, and filariasis.
Antimosquito measures are the major weapons against this group of diseases. Drugs
are available for the suppression and cure of malaria and a vaccine is available for the
prevention of yellow fever.
a. Malaria. Of the mosquito-borne diseases, malaria is the greatest threat to
military operations. Although the occurrence of malaria is rare in the US, it is common
in most tropical, subtropical, and semitropical areas of the world. Malaria is caused by a
microscopic parasite carried by the Anopheles mosquito. This parasite destroys the
blood cells and causes chills, fever, weakness, and anemia. Unless the disease is
treated promptly and properly, it may cause death from damage to the brain. The only
sure way of preventing malaria is to avoid the bites of infected mosquitoes. When
complete mosquito control (paragraph 5-3) is difficult or even impossible (such as
during periods of active combat), the prevention of malaria is dependent upon the
application of individual protective measures against the bites of mosquitoes (paragraph
1-28) and the use of antimalarial drugs. These drugs are referred to as suppressive
drugs in that they do not actually prevent infection by the disease organisms. Rather,
they destroy the parasites within the infected person's body and thus suppress the
b. Yellow Fever. Yellow fever is a viral disease now confined to tropical Africa
and tropical America. The virus is primarily transmitted by Aedes aegypti mosquito.
Yellow fever is characterized by fever, headache, backache, jaundice, and internal
bleeding. The most important preventive measures include the administration of a
highly effective vaccine and the application of individual protective measures against the
bites of mosquitoes.
c. Dengue Fever. The term "dengue" refers to a group of viral diseases that
are widespread throughout the tropical areas of the world. These diseases are
transmitted by Aedes mosquitoes. Often the only symptom is a mild fever, but there
may also be severe muscular pain. No vaccine is available for these diseases. The
best means for avoiding dengue fever is the prevention of mosquito bites by using
individual protective measures.
d. Encephalitis (Sleeping Sickness). There are many forms of encephalitis
throughout the world. They are viral diseases that usually affect the central nervous