HUMAN PARASITES IN AFRICA

Human Parasites in Africa

Human Parasites in Africa

Introduction

The Division of Control of Tropical Diseases (CTD) in WHO has global responsibility for African trypanosomiasis, Chagas disease, dracunculiasis (guinea-worm disease), foodborne trematode infections, intestinal parasitic infections, leishmaniasis, lymphatic filariasis, malaria, onchocerciasis and schistosomiasis. National programmes to combat these diseases are supported by WHO, in many instances in collaboration with other international agencies, development aid agencies, nongovernmental organizations, and industry. The mission of CTD, working closely with the WHO Regional Offices, is to provide support to country activities, to promote, advocate and coordinate tropical disease control with the aim of improving the health status of individual communities and populations, and to contribute to social and economic development.

This paper discusses five of the diseases listed above: Chagas disease, dracunculiasis, lymphatic filariasis, onchocerciasis and schistosomiasis. Four of these have been targeted for global elimination by the World Health Assembly, the objectives being the interruption of transmission of Chagas disease by the year 2010; the eradication of dracunculiasis by 2008; the elimination of lymphatic filariasis by 2020; and the elimination of onchocerciasis as a public health problem in 11 West African countries by 2002.( Guilley, 2004)

Criteria for Establishing Elimination Programmes

Technical feasibility is the criterion for changing from control of infection to an objective of elimination or interruption of transmission. This requires that the disease has been adequately researched in terms of the causative organism, clinical impact, management, treatment and epidemiology. The change is facilitated by a breakthrough in the form of a new strategy and/or tool that can effectively and rapidly reduce the incidence of infection and disease using the infrastructures in place.

Public Health Strategy

Disease elimination or eradication programmes have to fit within the existing public health strategies. The essential public health functions in each country should include major parasitic disease problems as an integral and coherent part of the "Renewal of Health for All" process led by WHO.

Dracunculiasis

The disease is caused by a parasitic worm Dracunculus medinensis (guinea worm). The infection is acquired by humans through drinking water containing infected cyclops. This minute crustacean becomes infected by ingestion of the larvae of Dracunculus which are released into water when an infected person steps into it to relieve the pain caused by the emerging worm. The emergence of the adult worm through the skin, usually from the legs and feet, approximately one year after the individual concerned drank unsafe water, is extremely painful, causing fever, nausea and vomiting, and disabling the person for months.( Hippe, 2001)

There are 100 million people still at risk of infection. In 1997 alone, approximately 70,000 cases were reported, compared to the estimated 10 million individuals infected per annum before the inception of the eradication programme. This drastic reduction is the result of the efforts made jointly by the countries with WHO, UNICEF, CDC, Global 2000 and a multitude of other NGOs and industry. Although there are no specific drugs to treat or prevent infection, the recommended strategy aims at case containment of infected individuals, community-based surveillance, and provision of safe ...