GMS-CDC

ABSTRACT
Background:
Soil-transmitted helminth (STH) infections are among the most prevalent afflictions of humans who live in poor areas in the developing world. The morbidity caused by STH infections is most commonly associated with infections of high intensity. Intestinal nematode infections affect one fourth to one third of the world's population. In certain areas of Cambodia, Lao PDR and Vietnam, the prevalence of STH infections in women of child bearing age (WCBA) has already been determined, but the data are not complete and and the problem of anemia and hookworm infection remain largely unknown.

This study was conducted in order to assess the prevalence of helminth infections (including Ascaris lumbricoides, Trichuris trichiura and hookworm) and anemia status among WCBA in selected areas of Lao PDR, Cambodia and Vietnam. It was also designed to determine the risk factors associated with worm infection and anemia.

The study proposal, “Study on the prevalence of soil-transmitted helminthiasis and anemia status among women of child bearing age in Cambodia, Lao PDR and Vietnam” was jointly developed by the National Institute of Malariology, Parasitology and Entomology of Vietnam (NIMPE) (the Leading Institution); the National Center for Parasitology, Entomology and Malaria Control of Cambodia (CNM); the Center for Malaria, Parasitology and Entomology of Lao PDR (CMPE); and the National Institute of Public Health of Lao PDR (NIOPH). The study was conducted in six provinces, namely Tay Ninh and Son La provinces in Vietnam; Svay Rieng and Kampong Speu in Cambodia; and Xieng Khouang and Xekong provinces in Lao PDR from September 2009 to April 2010 with technical and financial support from the Regional Coordination Unit of the Asian Development Bank Great Mekong Sub-region Communicable Disease Control Project.

Objectives of the study:

1. To assess the STH infections in women of child bearing age (15-45 years) in high and moderately endemic areas in Cambodia, Lao PDR and Vietnam.
2. To assess the anemia situation in women of child bearing age (15-45 years) in high and moderately endemic areas for STH in Cambodia, Lao PDR and Vietnam.
3. To examine if there is a relationship between STH infection status and anemia status in the study sites.

Methods:

Stool and blood samples were collected from 3,000 women of child bearing age (15-45 years old) in six provinces in Lao PDR, Cambodia and Vietnam. Single Kato-Katz smears were prepared and read to obtain the number of eggs per gram of STH in stool. A finger prick was performed to measure the hemoglobin levels. A questionnaire survey was carried out on sanitation and hygiene practices, targeting 1,000 WCBA in each country, in order to identify risk factors for anemia and STH infection.

Conclusions and Recommendations

The present study revealed high prevalence of hookworm infections and anemia in WCBA indicating they are significant public health problems of WCBA in Lao PDR, Cambodia and Vietnam.. The STHs which were found to be prevalent were T. trichiura (6.3%), A. lumbricoides (5.5 %), hookworm (27.2%) and other parasites (1.5%) in three countries. Higher infection rate of hookworm than other STH in the three should be an issue requiring further studies.

The overall prevalence of anemia among WCBA in the three countries in the study was 31.4% (943/3,000); 32.9% in LaoPDR, 29.1% in Cambodia and 32.3% in Vietnam, respectively. This is a high anaemia rate and the current study also found it significantly correlating with hookworm infection. Further, anemia was found in all of the age groups of WCBA of three countries.
Occupational status and educational status were associated with STH infection and women in blue collar occupations such as farming and those with lower level of education had higher infection and anaemia rate. This finding should be taken into consideration when designing the health educational and other interventional campaigns.

Significant proportion of women had knowledge on STH infection and how to prevent them but this knowledge was not associated with low worm burden signifying that having knowledge alone does not help much without environmental improvement. Attempts should be made to convert knowledge on STH into WCBAs adopting favourable behaviors. Both the availability and use of latrines should be increased in all three countries.
Mass drug administration should be conducted in all endemic areas in the three countries targeting WCBA. Much higher infection rate with hookworms than with other STHs shows the need to look for more efficacious drugs against hookworm and also monitor development of any resistance for those drugs currently being used in mass drug administration.

It will be important to support not only deworming but also iron, folic acid and other vitamin supplementation.

It is also important to determine the other causes of anemia for planning anemia prevention strategies.

The study report can be downloaded here:

 NIMPE - Scientific report - Final (3.87 MB)

 NIMPE - Scientific report - Final (Vietnamese language) (4.09 MB)