Review on the epidemiological profile of helminthiases and their control in the Western Pacific region, 1997–2008
Overview
Neglected tropical diseases (NTD) affect large segments of the world population, mainly the poor and the hard to reach population groups where lack of access to health care and other services is already a problem. Although most of these diseases will not cause death, they will often result in debilitating complications, contributing to malnutrition and disabilities such as in the case of onchocerciasis (can cause blindness) and lymphatic filariasis (can cause elephantiasis).
NTD pathogens include viruses, bacteria, fungi, ecto-parasites and helminths. Most of these are diseases of poverty. Many will target primarily ethnic minorities, children and women in childbearing age. The World Health Organization is highly committed to addressing the NTDs. Prevention and control of NTDs can significantly contribute to the accomplishment of the Millennium Development Goals (MDG).
One of the key challenges is the lack of adequate data. NTDs are not subject to compulsory reporting. Available data seems to suggest that the highest disease burden is due to one group of NTD's, the soil-transmitted helminths (STH). It is estimated that more than 1.2 billion people might be infected with STHs and/or schistosomes in the Asia Pacific Region alone. STH infections cause morbidity by affecting nutritional status, growth and cognitive development in children. Some helminth infections are among the leading causes of anemia throughout the developing world.
Much less is known about the epidemiological profile of food born trematodes and cestodes. Indirect evidence provided by the veterinary public health sector suggests that the human public health dimension of these zoonotic infections may be underestimated.
A comprehensive review on the epidemiology of helminths in the Western Pacific Region (WPR) was conducted by the Western Pacific Regional Office of the World Health Organization. Data were collected through communications with WHO staff and country health officials, as well as through searches of online health databases and peer-reviewed publications. The profile for each country is divided into four categories of helminths: soil-transmitted helminths (Ascariasis, Trichuriasis and hookworm infections); food-borne trematodes (fascioliasis, chlonorchiasis, opisthorchiasis, and paragonimiasis); cestodes (taeniasis, cysticercosis, and echinococcosis); and schistosomes. Data from 1997 to 2008 were included in the review.
We expect this information to contribute to expanding our knowledge on the epidemiological profile of the aforementioned four worm categories. In doing so, it should raise the profile and level of attention needed to encourage effective public health interventions targeting a selected group of NTDs. Some countries and areas have already taken the lead in terms of collecting and sharing of information as well as engaging in control programs. Others will need to follow.
The current review is a "work in progress". Our expectation is that this will serve as the basis for a more extensive data bank on the four categories of helminths supporting the development of effective interventions as well as scaling up of existing ones. Efforts will be made to update the epidemiological profile of helminthiasis in the Western Pacific Region 1997-2008 as soon as more data become available.