L. DISTRIBUTION OF YELLOW FEVER

Essentially all of tropical Africa between 15° N. latitude and 10° S. latitude, along with a portion of Northern Rhodesia, can be considered as infected with yellow fever (urban and jungle) although numbers of reported cases vary considerably from year to year.

In South America urban yellow fever has been almost nonexistent in recent years. The jungle form of the disease still persists, however, in the Amazon Valley and other parts of Brazil, in parts of the other countries adjoining Brazil, and in Middle America as far north as Guatemala.

Yellow fever is without parallel in its potentialities for disrupting trade and commerce. The wide natural distribution of the transmitting mosquito, the ease with which persons exposed to the disease may be transported to distant ports within the incubation period and the capability of the virus of producing explosive outbreaks if introduced into the local mosquito population cause air and sea transport to avoid ports in which the disease has been reported recently.

M. HOOKWORM

Hookworm infection traditionally has been associated with pop tion groups of low economic status living in tropical and subtrop climates and, in terms of its incidence, distribution, and clinical eff has long been rated as mankind's worst worm disease.

Worldwide in distribution, hookworm probably infects upwar 400 million persons. Areas most severely affected are countrie Middle and South America and the West Indies, tropical and sout Africa, and much of south central, southeast and east Asia. infection also occurs in more temperate areas, such as Southeas United States, the Balkans, and in Poland.

Infection is acquired by penetration of hookworm larvae li in the soil, usually through the skin of the feet. Thus, the wea of shoes is an important factor in preventing infection. Linked deficient diet, even moderate infections of these blood-sucking w produces anemia, weakness, and listlessness. The infected ind ual's ability to produce is greatly lowered with a resultant cu earning capacity.

Mass treatment campaigns coupled with improved environme sanitation and health education activities have been shown t effective in reducing the hookworm burden of a population minimum level, although complete eradication has not been achi except in circumscribed areas.