The effectiveness of 4 monthly albendazole treatment in the reduction of soil-transmitted helminth infections in women of reproductive age in Viet Nam

doi:10.1016/j.ijpara.2009.01.013

International Journal for Parasitology

Volume 39, Issue 9, 15 July 2009, Pages 1037-1043

https://doi.org/10.1016/j.ijpara.2009.01.013 Get rights and content

Abstract

Soil-transmitted helminth (STH) infections are endemic in northern Viet Nam where the climate and agricultural practices, such as the use of human excreta as fertiliser and the use of wastewater for irrigation, favour transmission. An intervention was conducted in Yen Bai Province, north-west Viet Nam, to measure the effectiveness of single dose albendazole (400 mg) administered every 4 months for reducing the prevalence of STH infections in women of reproductive age. Stool samples were collected from women before the intervention and 3 and 12 months post-intervention. Information on a range of demographic and socio-economic variables was also collected to measure the major risk factors for high STH burden in this area. The prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infection in the baseline sample of 366 women were 76.2%, 19.2% and 29.1%, respectively. In the women who were surveyed at baseline and again at 3 and 12 months after the intervention (n = 118) cure rates were 71.3% for hookworm, 87.0% for A. lumbricoides and 81.4% for T. trichiura by the end of the 12 month study period (i.e. after three doses of albendazole). The main risk factor for hookworm infection was if women worked outside (odds ratio (OR) = 3.2 (95% Confidence Interval (CI) 1.6–6.2), P = 0.001) and the major risk factor for A. lumbricoides and T. trichiura infection was a lack of education. Low educational attainment was also the strongest risk factor for co-infection with all three species of STH (OR = 7.5 (95% CI 3.4–16.4), P < 0.001). The high rates of hookworm infection in this area of Viet Nam and the high cure rates for all three species of STH with 4 monthly albendazole treatment suggest that this programme should be expanded to all endemic areas in Viet Nam. The study also highlights the important contribution of education to women’s health.

Introduction

It is estimated that 4.5 billion of the world’s human population are at risk of infection with soil-transmitted helminths (STH) (Keiser and Utzinger, 2008). STH infections have been identified as major contributing factors to nutritional deficiencies (Stephenson et al., 2000, Crompton and Nesheim, 2002, Casapia et al., 2006, Jardim-Botelho et al., 2008) and impaired physical and cognitive development in children (Levav et al., 1995, Oberhelman et al., 1998, Sakti et al., 1999). STH infections are a major contributing factor in iron deficiency anaemia, especially among women of reproductive age (Stoltzfus et al., 1997, Zimmermann and Hurrell, 2007) and STH infections can affect pregnancy outcomes. Studies conducted in Sri Lanka and Nepal have demonstrated that administration of antihelminthic drugs to women during pregnancy is associated with significantly higher birth weight and improved survival of their infants (de Silva et al., 1999, Christian et al., 2004).

The main parasites that cause STH infection are hookworms (Ancylostoma duodenale and Necator americanus), Ascaris lumbricoides and Trichuris trichiura. Ascaris lumbricoides and T. trichiura infections are most common amongst school-aged children and the prevalence usually decreases with age (Needham et al., 1998). Heavy hookworm infections can also occur in childhood, but frequency and intensity is usually higher in adulthood and is very common among older populations (Needham et al., 1998, Galvani, 2005). A recent systematic review showed that a single dose of albendazole had high cure rates for hookworm and A. lumbricoides infections. However, a single dose of albendazole was found to be less efficacious in the treatment of T. trichiura infection (Keiser and Utzinger, 2008).

STH infections are endemic in Viet Nam where the local climate and agricultural practices such as the use of human excreta as fertiliser and the use of wastewater for irrigation favour the transmission of infections (Do et al., 2007). It is estimated that 33.9 million people in Viet Nam are infected with A. lumbricoides, 17.6 million with T. trichiura and 21.8 million with hookworm (van der Hoek et al., 2003). A recent randomised trial in Viet Nam showed that a single dose of albendazole resulted in a 75% reduction in mean hookworm eggs per gram (EPG) relative to placebo in adults, whereas a triple dose of albendazole resulted in an 88% reduction (Flohr et al., 2007). To date, most population-based anti-helminth programmes in Viet Nam have been targeted at school-aged children or women in their second or third trimester of pregnancy (Olsen et al., 2006).

In 2005, the National Institute for Malariology, Parasitology and Entomology (NIMPE) in Viet Nam initiated a demonstration public health program that integrated universal anaemia prevention and deworming into the existing health service structure in two districts of the northern mountainous province of Yen Bai. A baseline assessment for this program has been previously published (Pasricha et al., 2008). In this paper, we report on the impact of this program on the prevalence of STH infections in women of reproductive age and identify the major risk factors for high STH burden among women in this area of Viet Nam.

Section snippets

Subjects and setting

A 1-year demonstration anaemia and hookworm control intervention of weekly iron-folate supplementation (WIFS) with 4 monthly deworming (single dose treatment with albendazole given every 4 months) was introduced in two districts of Yen Bai province (Tran Yen and Yen Binh districts) in north-west Viet Nam from May 2006 to May 2007. The target population was all women of reproductive age (16–45 years) living in the two districts, approximately 52,000 women. Prior to the introduction of the

Results

In the study a total of 366 women had stool microscopy performed at baseline; 433 women at 3 months, and 467 women at 12 months. Of the 366 women tested at baseline, 118 also had stool microscopy data for both the 3 month and 12 month surveys. Table 1 shows a comparison of demographic variables for the 248 women who were only in the baseline survey, and the 118 women who attended all three surveys. There were some differences between these groups. Women who attended all three surveys were more

Discussion

This study confirms the high prevalence of STH infection, particularly hookworm infection, among women of reproductive age in north-west Viet Nam and shows a significant reduction in both the prevalence and intensity of STH infection with a single dose of albendazole (400 mg) given every 4 months over a 12 month period. Cure rates were 71% for hookworm, 87% for A. lumbricoides and 81% for T. trichiura in women who participated in all three surveys during the study period. This study also

Acknowledgements

The authors acknowledge the support of Yen Bai People’s Committee, district and commune health staff, and village health workers. We are grateful to the Yen Bai Malaria Control Program staff who were the local implementing agency, to Dr. Cavalli-Sforza who provided valuable suggestions and Pham Thi Xuyen, Beth Hilton-Thorp and Christalla Hajisava for invaluable contributions. Most importantly, we thank the women of Tran Yen and Yen Binh who participated in these surveys. Atlantic Philanthropy

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Indeed, in southern Vietnam, geohelminthic hookworm and ascaris infections with poor sanitation (unflushable toilets) protected against allergic sensitization.33 Since the year 2010 the prevalence of parasitosis decreased due to the large use of albendazole treatment (400 mg every 4 months) which cured more than 70% of the persons affected.34 In 2015, in southern rural of Vietnam, the prevalence of hookworm and ascaris were 22.8% and 2% 35 compared to 65% and 7% in 2006.33
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The use of tap water was a clear protective factor against helminth infections. The prevalence rates of helminth infection we found in our study lied within the range of prevalence rates reported in previous studies in Vietnam [21,23,25,26,29,39,40]. Several factors can be made responsible for this variation among which climate, types of soils and crops, SES, and human hygiene behavior are of most importance [41].
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The effectiveness of 4 monthly albendazole treatment in the reduction of soil-transmitted helminth infections in women of reproductive age in Viet Nam

Abstract

Introduction

Section snippets

Subjects and setting

Results

Discussion

Acknowledgements

Public Health

Int. J. Parasitol.

Lancet

Lancet

Trends Parasitol.

Trans. R. Soc. Trop. Med. Hyg.

Acta Trop.

Am. J. Clin. Nutr.

Lancet

Training Manual on Diagnosis of Intestinal Parasites – Tutor’s Guide

Mapping soil-transmitted helminthes in Southeast Asia and implications for parasite control

Southeast Asian J. Trop. Med. Public Health

Nutritional impact of intestinal helminthiasis during the human life cycle

Annu. Rev. Nutr.

Helminth infections among people using wastewater and human excreta in peri-urban agriculture and aquaculture in Hanoi, Vietnam

Trop. Med. Int. Health