Plague still a world killer, WHO warns.

Although human plague is often regarded as a terrible disease of the past - the "Black Death" killed countless millions in Europe alone during the Middle Ages - it continues to claim lives in Africa, Asia, North America, and South America, according to latest figures from the World Health Organization (WHO).

For 1992, the last full year for which figures are available, nine countries reported a total of 1,768 cases, including 198 deaths, to WHO. During the 15 years from 1978 to 1992, 14,856 cases were reported, including 1,451 deaths, in 21 countries.

Experts believe the world statistics on plague are incomplete, because of inadequate surveillance and reporting. In most countries, only bacteriologically or serologically confirmed cases are reported, and underreporting of plague due to the lack of laboratory facilities is not uncommon.

The nine countries where plague was known to have occurred in 1992 were Madagascar (198 cases, 26 deaths), Zaire (390 cases, 140 deaths), Brazil (25 cases, no deaths), Peru (120 cases, 4 deaths), United States (13 cases, 2 deaths), China (35 cases, 6 deaths), Mongolia (12 cases, 4 deaths), Myanmar (528 cases, 3 deaths) and Viet Nam (437 cases, 13 deaths).

Other countries reporting plague since 1978 include Angola, Botswana, Kenya, Libya, Mozambique, South Africa, Uganda, Tanzania, Zimbabwe, Kazakhstan, Bolivia, and Ecuador.

Plague spreads mainly from rats to humans by fleas biting first a sick rat and then a person, thus transmitting the bacillus, Yersinia pestis.

Plague most commonly has three forms - bubonic, pneumonic, and septicemic, corresponding to the three typical ways in which the plague bacillus invades the body. The commonest form is bubonic, with a sudden onset of severe malaise, headache, shaking chills, fever, and pain in the affected regional lymph nodes. The most obvious symptom is swelling of the lymphatic glands nearest the point of the infected bite or skin lesion into large, hard and painful tumors called buboes.

The most dangerous form of the disease is pulmonary plague, which affects the lungs and can be transmitted to other people by droplets in the air containing plague bacilli from sputum discharged by the patient.

Plague patients should be treated with antibiotic drugs such as streptomycin, kanamycin, chloramphenicol, and tetracyclines, that are effective, provided that they are used properly and in time.

Vaccines against plague are available, but WHO warns that because they provide limited, short-term immunity requiring revaccination - which in turn has adverse side effects - vaccination is recommended only for high-risk groups such as laboratory personnel working on plague or field workers in endemic areas. It should only be used for the prevention of plague and not as a means of control during outbreaks. [Reprinted from Public Health Reports, Sept.-Oct. 1994, 109(5):717.]