Outbreaks are most common among children in schools or other institutions.
The infesting agents of pediculosis are Phthirus pubis (the crab louse), Pediculosis humanus capitis (the head louse), and P. humanus corporis (the body louse). The reservoir is man. Head and body lice are most commonly transmitted by direct contact with an infested person. Body lice and less frequently head lice are also transmitted by indirect contact with the personal belongings of an infested person, e.g., clothing and headgear. Crab lice are most frequently transmitted through sexual contact.
Lice are heat sensitive organisms and will leave a host with fever. Transmission easily occurs from person to person under crowded conditions. With ideal conditions lice eggs hatch in 7 days and reach sexual maturity in 8 to 10 days. Pediculosis is communicable as long as lice or eggs remain on an infected person or clothing.
Lice may be treated with 1 percent gamma benzene hexachloride lotions (Lindane, Kwell). (It should not be used on infants, young children, or pregnant or lactating women.) Normally a second application 7 to 10 days later is recommended to treat any eggs that survived. Clothing and bedding may be disinfected by washing in hot water.
Plague is a disease of animals and man (zoonosis) that is transmitted by a flea bite from infected rodents to susceptible animals, including man. The first sign is usually an inflammation of lymph nodes (bubonic plague) in the inguinal, axillary, or cervical regions, depending on the location of the flea bite. Lymph nodes may form pus, and fever develops. Septicemia may develop and carry the disease to other organs or systems, including the membranes covering the brain. When the lungs are affected (pneumonic plague), the disease may be transmitted from man to man by direct respiratory contact (coughing, spitting) or direct projection and may result in outbreaks or epidemics. The fatality rate for bubonic plague may reach 50 percent. Without treatment, septicemic plague and pneumonic plague are usually fatal. The fatality rate of all types of plague may be reduced with prompt diagnosis and medical treatment.
Diagnosis may be established by observing plague organisms in gram stains, and cultures of material from a bubo, sputum, or spinal fluid.
The natural reservoir of plague is wild rodents, which can be in contact (and transmit their fleas) with domestic rats. Wild rodent plague has been found in many countries including those of North America, South America, the Middle East, Africa, Southeast Asia and Europe. In all areas of wild rodent plague, human plague can and does occur.
The infectious agent is Yersinia pestis. The reservoir is usually wild rodents, possibly rabbits, and larger carnivores. The incubation period is from 1 to 6 days.
With favorable weather, infected fleas may be communicable for several months. Pneumonic plague is easily transmitted from man to man under crowded conditions when susceptible persons are in close contact with cases. Persons who have recovered from plague may acquire the disease again with an additional exposure. Treatment with early antibiotic therapy (preferable within 8 hours and not later than 24 hours from the onset) is effective for pneumonic plague. There may be secondary infection. Bubos may require incision and drainage.
Preventing flea bites on humans and avoiding exposure of susceptible persons to pneumonic plague cases are the primary methods of control. Specific measures include (1) in endemic areas, establishing information programs to educate the public about infected rodents/fleas; (2) routine surveys of domestic and wild rodent populations to evaluate environmental control programs (e.g., poisoning and trapping programs) and the possibility of plague transmission from rodents to man; and (3) rodent and flea control in and around port facilities requiring additional steps, including the prevention of rat movement to and from ships (rat guards) and shipboard poisoning and fumigation.
Management of patients, contacts, and the nearby environment includes (1) disinfection and isolation of patient clothing and baggage; (2) ensuring that all persons exposed to pneumonic plague be isolated and placed on chemoprophylaxis with close surveillance for 7 days; (3) disinfestation of all contacts with bubonic plague patients and chemoprophylaxis for household contacts; (4) attempt to find all close contacts (e.g., household contacts and face-to-face contacts) exposed to pneumonic plague, as well as dead or dying rodents and their fleas; and (5) vaccination for persons living in high plague areas, laboratory workers, and field workers.
International measures stipulate that ships and aircraft arriving from plague areas must follow