polluted water), and eating food prepared/served with unwashed hands. The average incubation period is 2 to 3 days. It is communicable during the period when the stool is positive for Vibrio cholerae; this period continues for a few days after recovery. Patients who develop into carriers may be communicable for several months.
The primary treatment is with the administration of large amounts of oral or intravenous fluids. Antibiotics given at the direction of a medical officer may be helpful in reducing the duration and severity of diarrhea and fluid loss. Preventive measures for control of the disease include (1) proper disposal of human feces; (2) providing clean drinking water and water treatment and disinfection; and (3) emphasizing good personal hygiene, especially handwashing before eating and after using the latrine.
Management of patients, contacts, and the nearby environment requires (1) isolation of patients by enteric (gastrointestinal) precautions, e.g., handwashing and disposal of intestinal excretions; (2) observing contacts of patients for symptoms 5 days from the last exposure (antibiotic prophylaxis and immunization are not routinely recommended); and (3) conducting an investigation for the source of the infection. There is no requirement for quarantine.
Epidemic control entails (1) providing clean potable water and sanitary sewage disposal; (2) identifying the location of the source of infection and appropriate control methods; and (3) ensuring sanitary food handling.
There are some international requirements. Ships and aircraft arriving from cholera areas must follow procedures outlined in International Health Regulations; details are found in SECNAVINST 6210.2. Except for a few specified countries, immunization is not required for international travel.
Dengue Fever (Breakbone fever)
Dengue fever is characterized by a sudden onset of fever (occasionally lasting 7 days or more), intense headache, pain behind the eyes, joint and muscle pain, and a rash. There is early redness of the skin in some patients; usually for 3 to 4 days after the beginning of fever, a rash presents with small discolored raised spots or closely aggregated bright red points. Minute hemorrhagic or purpuric spots may appear on the feet, legs, axillae, or palate at about the same time the temperature returns to normal. Patients with dark skin often have no visible rash.
The infectious agents are the viruses of dengue fever (types 1, 2, 3, and 4). These viruses also cause dengue hemorrhagic fever (discussed later). The reservoir is either man-mosquito or monkeymosquito, depending on the geographic area. Dengue is endemic to tropical Asia, West Africa, parts of the Caribbean, and several countries in Central and South America.
The virus is transmitted to man by the bite of mosquitoes belonging to the genus Aedes. Mosquitoes acquire the virus by biting man and, in some areas, monkeys. The incubation period is usually 5 to 6 days. Patients are normally infective to mosquitoes 24 hours before the onset until the fifth day of the disease. Treatment is supportive; there are no specific antibiotics.
Preventive measures require (1) implementing mosquito surveys in affected communities to determine the density of vector mosquitoes, identifying breeding places, and eliminating the vectors where practical; and (2) making information available to the public concerning methods for protection from the vector mosquito bites such as the use of repellents, screening, and bed nets.
Management of patients, contacts, and the nearby environment includes (1) precautions with patient blood by denying mosquitoes access to the patient for at least 5 days after attack by using screens, an approved residual insecticide, or by the use of bed nets; and (2) investigation of a case including the place of residence at the time of infection (3 to 15 days prior to the onset) and search for unreported or undiagnosed cases. There is no requirement for quarantine or immunization.
Epidemic measures, when necessary, include (1) surveying, locating, and eliminating all manmade Aedes mosquito breeding places; (2) encouraging all persons who are occupationally exposed to the vectors to use repellents; and (3) air dispersal of approved insecticides to stop epidemics.
International measures require strict enforcement of all existing international agreements designated to prevent the spread of this disease by man, monkey, and mosquitoes via ships, airplanes, and land transportation from endemic areas.
Dengue Hemorrhagic Fever
This severe illness affects primarily children, but cases can be seen in adults. Symptoms and signs include circulatory shock, high fever, loss of appetite, vomiting, headache, and abdominal pain. A hemorrhagic phenomenon is seen, which