Next Page

Chapter 12

Ancylostomiasis (Hookworm Disease)

Estimates of the number of people in the world infected with blood-sucking hookworms range from 800 million to 1.25 billion people (WHO, 1997), with at least 1.6 million suffering from significant anemia and 65,000 deaths annually. Forty-four million pregnant women are infected with hookworms, increasing their risk of iron deficiency anemia and related adverse effects on fetal growth, prematurity, and below normal birth weight. Despite these staggering statistics, there is reason for hope, since hookworms are readily eradicated by albendazole, mebendazole and other anthelmintics. Spectacular results reported by the WHO (1998) in Zanzibar, where over 99% of children harbor hookworms, prove that regular deworming increases their weight and height, improves iron stores, and reduces iron deficiency anemia, preventing the loss of 250 ml of blood per child per year at a cost of only 15 U.S. cents. By the year 2,000 intestinal helminth control programs should be implemented in at least 50% of endemic countries.

As recently as 1990, hookworms were the most common human intestinal helminths identified by state diagnostic laboratories in the southern United States and Puerto Rico. Next to malaria, hookworm disease has probably attracted the attention of more physicians in the tropics than any other parasitic disease. Yet, despite progress in its eradication and control, it remains a major problem in many developing countries, causing considerable debility and poverty. It is not a disease which the radiologist will find easy to diagnose.

Probably the earliest references to hookworm disease go back to the papyrus papers of ancient Egypt (1600 B.C.), where it was described as a derangement characterized by anemia. Avicenna, a Persian physician of the 11th century, discovered the worm in several of his patients and related it to their disease. During the 19th century, the relationship between hookworms and anemia was established, and the disease became a focus of special concern in 1880 when it caused several fatal epidemics among miners in France and Germany. In 1897, it was established that the skin was the principal avenue of infection and the life cycle of the hookworm was clarified.

In 1899, Stiles discovered that the "progressive pernicious anemia" seen in the southern United States was caused by Ancylostoma duodenale, and at the same time he defined two distinct species of hookworm capable of infecting man: Uncinaria (Ancylostoma) duodenale (the Old World hookworm) and Uncinaria (Necator) americanus (the New World hookworm). This newly found American species undoubtedly originated in Africa and was brought to the Americas during the slave trade.

Synonyms

Hookworm disease. Ancylostomiasis. Necatoriasis. Uncinariasis. Tropical anemia. Miner's anemia. Safura.

Sp: Necator americano Anquilostomiasis. Mal de minero. Anemia de los ladrilleros. Fr: Necateur americain. Ger: Todeswurm. Hakenwurm.

Definition

Ancylostomiasis is an infection with one or more species of nematodes belonging to the family Ancylostomidae. The common hookworms are Ancylostoma duodenale and Necator americanus. Both species may infect the same person. Rarely, Ancylostoma ceylanicum, which occurs in cats, can cause human infection.

Back to the Table of Contents

Next Page

Copyright: Palmer and Reeder by Springer

USED WITH PERMISSION

Tropical Medicine Mission Index of Diseases About Tropical Medicine Tropical Medicine Home Page Tropical Medicine Staff