The associations between water and sanitation and hookworm infection using cross-sectional data from Togo's national deworming program.

BACKGROUND: Sustainable control of soil-transmitted helminths requires a combination of chemotherapy treatment and environmental interventions, including access to safe drinking water, sufficient water for hygiene, use of clean sanitation facilities, and handwashing (WASH). We quantified associations between home-, school-, and community-level WASH characteristics and hookworm infection-both prevalence and eggs per gram of stool (intensity)-among Togolese school children in the context of community-based chemotherapy treatments administered in the country from 2010 through 2014. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed data from two surveys conducted by the Togo Ministry of Health: a school-based survey of students aged 6-9 years across Togo conducted in 2009 and a follow-up survey in 2015, after four to five years of preventive chemotherapy. Data were available for 16,473 students attending 1,129 schools in 2009 and for 16,890 students from 1,126 schools in 2015. Between surveys, children in study schools received 0 to 8 rounds of deworming chemotherapy treatments. Few WASH conditions (only unimproved drinking water) were found to be significantly associated with the presence or absence of hookworms in an individual; however, quantitative eggs per gram of feces was associated with availability of unimproved drinking water, availability of improved drinking water either on or off school grounds, having a handwashing station with water available, and access to a sex-separate non-private or private latrine. The association between school WASH conditions and hookworm infection or burden often depended on the 2009 prevalence of infection, as more WASH characteristics were found to be significant predictors of infection among schools with high underlying endemicity of hookworm. CONCLUSIONS/SIGNIFICANCE: Our findings emphasize the complex and often inconsistent or unpredictable relationship between WASH and hookworm. Specifically, we found that while preventive chemotherapy appeared to dramatically reduce hookworm infection, WASH was associated with infection intensity.

Contribution of Wastewater Irrigation to Soil Transmitted Helminths Infection among Vegetable Farmers in Kumasi, Ghana.

Wastewater irrigation is associated with several benefits but can also lead to significant health risks. The health risk for contracting infections from Soil Transmitted Helminths (STHs) among farmers has mainly been assessed indirectly through measured quantities in the wastewater or on the crops alone and only on a limited scale through epidemiological assessments. In this study we broadened the concept of infection risks in the exposure assessments by measurements of the concentration of STHs both in wastewater used for irrigation and the soil, as well as the actual load of STHs ova in the stool of farmers and their family members (165 and 127 in the wet and dry seasons respectively) and a control group of non-farmers (100 and 52 in the wet and dry seasons, respectively). Odds ratios were calculated for exposure and non-exposure to wastewater irrigation. The results obtained indicate positive correlation between STH concentrations in irrigation water/soil and STHs ova as measured in the stool of the exposed farmer population. The correlations are based on reinfection during a 3 months period after prior confirmed deworming. Farmers and family members exposed to irrigation water were three times more likely as compared to the control group of non-farmers to be infected with Ascaris (OR = 3.9, 95% CI, 1.15-13.86) and hookworm (OR = 3.07, 95% CI, 0.87-10.82). This study therefore contributes to the evidence-based conclusion that wastewater irrigation contributes to a higher incidence of STHs infection for farmers exposed annually, with higher odds of infection in the wet season.

Prevalence and risk factors of soil-transmitted helminth infection in Nepal.

BACKGROUND: The purpose of this study is to evaluate the prevalence and intensity and examine the risk factors of soil transmitted helminth (STH; i.e., roundworm [Ascaris lumbricoides], hookworms [Ancylostoma duodenale and Necator americanus], and whipworm [Trichuris trichiura]) infections in Nepal. METHODS: Five hundred and ninety-four adults (256 men and 338 women) were selected via convenience sampling from five communities in Nepal. The Kato-Katz method was used to assess the prevalence and intensity of STH infection in this population. RESULTS: Prevalence of STH infection ranged from 3.3% in Birendranagar in Chitwan, 3.5% in Kuleshor in Kathmandu, 11.7% in Kanyam in Ilam, 17.0% in Dhikurpokhari in Kaski and 51.4% in Khokana in Lalitpur District [corrected]. Multivariable regression analysis revealed that not using soap for hand-washing was significantly associated with the prevalence and infection intensity of roundworm, hookworms and whipworm. Similarly, not wearing sandals or shoes outside was significantly associated with the prevalence and infection intensity of roundworm and hookworms, but not with infection intensity of whipworm. Literacy, being underweight or overweight, anemia and occupation were not associated with prevalence and intensity of roundworm and hookworms infection, but there was an association between occupation and the prevalence of whipworm infection. CONCLUSION: STH infection was associated with individual hygiene behavior, but not with nutritional status or socio-demographic characteristics. Health policy focusing on changing individual hygiene behaviors might be useful in addressing STH infection in Nepal.

Wastewater quality and the risk of intestinal nematode infection in sewage farming families in hyderabad, India.

Use of sewage or wastewater in agriculture is becoming increasingly common as a result of a global water scarcity. Intestinal nematode infections have been identified as the main health risk associated with this practice. To protect consumer and farmer health, the World Health Organization (WHO) has established an intestinal nematode water quality standard. However, because of a lack of well-designed studies, the validity of this guideline is questioned. This report presents the findings of a study on the risk of intestinal nematode infections in farming families occupationally exposed to untreated and partially treated wastewater in Hyderabad, India. The study found an increased risk of hookworm (odds ratio [OR] 3.5, 95% confidence interval [CI] = 2.2-5.5), Ascaris lumbricoides (OR = 5.3, 95% CI = 2.0-14), and Trichuris trichiura (OR = 5.6, 95% CI = 1.8-18) infection when untreated wastewater (150 intestinal nematode ova/liter) was used for crop production. Use of partially treated wastewater (28 intestinal nematode ova/liter) was only associated with an increased risk (OR = 3.2, 95% CI = 1.2-8.6) of A. lumbricoides infection. The findings of the study suggest that the current WHO intestinal nematode guideline of 1 ova/liter is sufficient to protect farmer health.

An itchy holiday.

A 33-year-old Dutch woman developed itchy skin lesions during a beach holiday in Thailand. She was treated for various diagnoses, without success. Finally she was successfully treated for a clinically suspected hookwormrelated folliculitis. A brief overview of hookworm-related folliculitis is given.

High risk of hookworm infection among wastewater farmers in Pakistan.

The health risks of wastewater use in agriculture were investigated in the city of Faisalabad, Pakistan, by means of a cross-sectional study. The study showed an increased risk of intestinal nematode infection and hookworm infection, in particular, in wastewater farmers (OR = 31.4, 95% CI 4.1-243) and their children (OR = 5.7, 95% CI 2.1-16) when compared with farming households using regular (non-wastewater) irrigation water. Textile labourers living in the same village as the wastewater farmers showed a lower risk of hookworm infection than wastewater farmers but an increased risk compared with farming households using regular irrigation water. Many urban and peri-urban farmers make a living by using untreated wastewater in the production of fresh produce for the urban market. Banning the use of untreated wastewater would deprive these farmers of their livelihood and affect food supply for the urban population. If treatment of wastewater is not a feasible option, the promotion of footwear and improved hygiene, the construction of toilets, in combination with regular anthelminthic treatment, would be suitable alternatives to safeguard the health of wastewater farmers and their children.

Earth-eating and reinfection with intestinal helminths among pregnant and lactating women in western Kenya.

We conducted a longitudinal study among 827 pregnant women in Nyanza Province, western Kenya, to determine the effect of earth-eating on geohelminth reinfection after treatment. The women were recruited at a gestational age of 14-24 weeks (median: 17) and followed up to 6 months postpartum. The median age was 23 (range: 14-47) years, the median parity 2 (range: 0-11). After deworming with mebendazole (500 mg, single dose) of those found infected at 32 weeks gestation, 700 women were uninfected with Ascaris lumbricoides, 670 with Trichuris trichiura and 479 with hookworm. At delivery, 11.2%, 4.6% and 3.8% of these women were reinfected with hookworm, T. trichiura and A. lumbricoides respectively. The reinfection rate for hookworm was 14.8%, for T. trichiura 6.65, and for A. lumbricoides 5.2% at 3 months postpartum, and 16.0, 5.9 and 9.4% at 6 months postpartum. There was a significant difference in hookworm intensity at delivery between geophagous and non-geophagous women (P=0.03). Women who ate termite mound earth were more often and more intensely infected with hookworm at delivery than those eating other types of earth (P=0.07 and P=0.02 respectively). There were significant differences in the prevalence of A. lumbricoides between geophagous and non-geophagous women at 3 (P=0.001) and at 6 months postpartum (P=0.001). Women who ate termite mound earth had a higher prevalence of A. lumbricoides, compared with those eating other kinds of earth, at delivery (P=0.02), 3 months postpartum (P=0.001) and at 6 months postpartum (P=0.001). The intensity of infections with T. trichiura at 6 months postpartum was significantly different between geophagous and non-geophagous women (P=0.005). Our study shows that geophagy is associated with A. lumbricoides reinfection among pregnant and lactating women and that intensities built up more rapidly among geophagous women. Geophagy might be associated with reinfection with hookworm and T. trichiura, although these results were less unequivocal. These findings call for increased emphasis, in antenatal care, on the potential risks of earth-eating, and for deworming of women after delivery.

Current status of soil-transmitted helminths in Vietnam.

This paper provides a review of surveys on soil-transmitted helminths that were done in Vietnam between 1990 and 2001. Prevalence estimates could be obtained for 29 of the 61 provinces. Extrapolating from this, it is estimated that 33.9 million people in Vietnam are infected with Ascaris (prevalence 44.4%), 17.6 million with Trichuris (prevalence 23.1%), and 21.8 million with hookworm (prevalence 28.6%). Prevalence of Ascaris and Trichuris showed a declining trend from the north to the south of the country. This is probably related to differences in climatic conditions. Hookworm prevalence is more evenly distributed throughout the country, but is concentrated in peri-urban and rural agricultural areas. Vegetable cultivation in which nightsoil is used as fertilizer is a risk factor for hookworm infection, especially among adult women. Helminth control programs should be targeted at school-age children in the northern provinces. Specific interventions are needed throughout the country for women of agricultural communities that are at risk for hookworm infection. There is clearly a need for more detailed analysis of risk factors to quantify the relative contribution of climatic, environmental, and human behavioral factors in the transmission of intestinal nematode infections in Vietnam.

Etiology of childhood diarrhea in Beijing, China.

To determine the role of recently recognized enteropathogens in childhood diarrhea in China, 221 children with diarrhea and 108 controls seen at the Beijing Children's Hospital were studied during April and May 1989. Stools were examined for ova, parasites, and rotavirus, cultured for bacterial pathogens, and probed for enterotoxigenic Escherichia coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), and enteropathogenic adherence factor-positive (EAF+) E. coli. Pathogens were identified in 56.5% of children with diarrhea and 43.5% of controls (P = 0.04). Detection of enteropathogens was significantly greater in patients examined within 1 week of symptom onset (65%) than in patients examined later (39%; P = 0.01). ETEC was the most frequently detected pathogen in children with diarrhea, accounting for 20% of the cases. Other agents identified in patients included the following: salmonellae, 12%; rotavirus, 7%; EIEC, 7%; EHEC, 7%; members of the Aeromonas hydrophila group, 6%; EAF+ E. coli, 5%; Ascaris lumbricoides, 3%; shigellae, 3%; campylobacters, 2%; and Vibrio spp., 0.5%. The isolation rates of salmonellae (P = 0.02), EAF+ E. coli (P = 0.04), and mixed pathogens (P = 0.05) were significantly greater for diarrhea patients than for controls. Resistance to multiple antimicrobial agents occurred in 39% of the Salmonella isolates, 22% of the Aeromonas isolates, and 17% of the Shigella isolates. Multiresistant salmonellae (P = 0.05) and shigellae were recovered from diarrheal stools only. Ciprofloxacin, cefotaxime, and imipenem were the only agents tested to which all bacterial isolates were susceptible in vitro. These results suggest that both traditional and newly recognized agents are important causes of childhood diarrhea in Beijing and that therapy may be complicated by indigenous antimicrobial resistance.

Man, an accidental host of Cyclodontostomum purvisi (Adams, 1933), and the occurrence in rats in Thailand.

Two adults of Cyclodontostomum purvisi were recovered from faecal specimen of a 47 year-old male who had suffered from capillariasis, in Kaeng Khoi District, Saraburi Province, Thailand; Adults of C. purvisi were also recovered from the large intestine of B. savilei and B. indica trapped in the same area and in Pak Philli District, Nakhon Nayok Province. This is the first record of human infection with C. purvisi and of the occurrence in B. savilei and B. indica in Thailand.