from sewage-contaminated water, raw fruits and vegetables, and contaminated milk and milk products are important vehicles in some areas of the world.
Typhoid fever is communicable as long as typhoid bacilli remain in the feces or urine. Many patients not appropriately treated become permanent carriers.
Specific antibiotics are the treatment of choice.
Preventive measures include (1) in field situations, providing for the sanitary disposal of human feces, and adequate handwashing facilities; (2) ensuring that fly proof latrines are away from and downstream from the source of drinking water; (3) controlling fly populations by screening, with insecticides, and by the proper collection and disposal of garbage to prevent breeding places; (4) requiring proper food preparation and handling and proper refrigeration; (5) at foreign ports, limiting the acquisition of shellfish to supplies from approved sources; (6) instructing patients, convalescents, and carriers concerning food personal hygiene; (7) excluding carriers and infected persons from food handling. Immunization for the general population in the United States is not recommended. Immunization boosters are required for many Navy and Marine Corps personnel and recommended for travelers to endemic areas.
For patients, isolation includes enteric precautions while they are ill. Cases should not be released from medical supervision until three consecutive cultures of feces taken at 1 month intervals after the onset and 24 hours apart are negative. If any one of these cultures is positive, repeat at intervals of 1 month until three negative cultures are obtained. Do not assign household contacts to food handling until two feces cultures taken 24 hours apart are negative.
The probable or actual source of every case should be determined by searching for unreported cases, carriers, and contaminated food, water, milk, or shellfish.
Epidemic measures include (1) searching for cases, carriers, or contaminated food or water that may be transmitting the infections; (2) the exclusion of suspected food; and (3) disinfecting all suspected water with chlorine or iodine, or boiling it before use.
During natural disaster situations, the transmission of typhoid fever may be expected with the disruption of food and water supplies and excreta disposal in a displaced population if cases or carriers are present. Vaccination of such populations is not generally recommended; efforts to provide safe food, water, and excreta disposal are more effective.
Typhus is caused by rickettsial agents, similar to bacteria. The onset is frequently sudden and commences with general pain, fever, chills, headache, and prostration. After 5 to 6 days, a macular red rash becomes apparent on the upper trunk and then covers all the body, usually with the exception of the soles, palms, and face. Toxemia is normally present. After about 2 weeks of fever, typhus ends with rapid recovery. Without specific treatment, the fatality rate is 10 to 40 percent and increases in older persons. Cases may be mild with an absence of rash, particularly in children and persons partially protected by a previous immunization. In the Brill-Zinsser Disease, typhus recurs (without another exposure) many years after recovery from the first infection. The Brill-Zinsser disease is less serious with milder symptoms and has a lower fatality rate.
Diagnosis may be established by serological tests.
In the past, outbreaks of typhus often accompanied famine and war. Typhus is endemic in the mountainous areas of Central and South America, central Africa, and many countries in Asia. In the United States, the infectious agent causes a disease in flying squirrels, which may be passed to man by their fleas.
The infectious agent is Rickettsia prowazekii. The reservoir is man. Typically, the body louse is infected when it feeds on the blood of a person with typhus fever. Man is infected by crushing and rubbing an infected louse or its feces into the bite wound or other break in the skin. Some cases may result from inhalation of dried airborne flea feces. The incubation period averages about 12 days.
Treatment is with antibiotics.
Methods of control include control of lice with insecticide dusts, washing clothes and bathing, and immunization of susceptible persons at high risk, e.g., local military and labor forces and residents.
Management of patients, contacts, and the nearby environment includes ( 1 ) no requirement for isolation after delousing patients, contacts, clothing, and quarters; (2) concurrent disinfection of patients, contacts, bedding, and clothing with approved insecticides; (3) quarantine for 15 days for susceptible louse-infected persons exposed to typhus; and (4) surveillance of immediate contacts for 2 weeks.