High risk of hookworm infection among wastewater farmers in Pakistan

Ensink, Jeroen H. J.; Hoek, Wim van der; Mukhtar, Muhammad Uzair; Tahir, Zarfishan; Amerasinghe, Felix P.

doi:10.1016/j.trstmh.2005.01.005

Cited by 61 publications

(57 citation statements)

References 15 publications

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“…Acquiring hookworm infection is directly related to exposure to soil where filariform larvae, the infective stage, live in and penetrate human skin. 4,15,16 Poor personal hygiene, particularly defecation practices [16][17][18][19] and sanitation, 17,20 have been reported as risk factors of hookworm infection. Hookworm infection has been associated with low socioeconomic status 16 and low educational attainment.…”

Section: Discussionmentioning

confidence: 99%

Incidence and Risk Factors of Hookworm Infection in a Rural Community of Central Thailand

Jiraanankul¹,

Aphijirawat²,

Mungthin³

et al. 2011

The American Journal of Tropical Medicine and Hygiene

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Section: Discussionmentioning

confidence: 99%

Incidence and Risk Factors of Hookworm Infection in a Rural Community of Central Thailand

Jiraanankul¹,

Aphijirawat²,

Mungthin³

et al. 2011

The American Journal of Tropical Medicine and Hygiene

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“…In the QMRA model, the number of days a farmer works in the field over a year equates to the number of days they are likely to accidentally ingest contaminated soil, though there is lack of evidence to support this. In addition the QMRA model assumes only a faecal-oral transmission route for pathogens in wastewater contaminated soil, not for exposure to water, nor for direct contact with contaminated soil, even though other modes of transmission are well established [103][104][105]. The paucity of data for risk assessment therefore calls for more field-based data that can help validate, and improve the accuracy, and reliability of risk estimates from QMRA models.…”

Section: Introductionmentioning

confidence: 99%

Wastewater use in urban agriculture: an exposure and risk assessment in Accra, Ghana

Agyei

Ensink

2016

Jnl Sci Tech

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In order to minimize the health risks to agricultural workers, and consumers of wastewater irrigated produce, the World Health Organisation has developed guidelines for the safe use of wastewater in agriculture. This study sought to test the appropriateness of the current Quantitative Microbial Risk Assessment model and the multiple-barrier approach advocated by the WHO guidelines.Over a one year period, over 500 produce and ready-to-eat salad samples were collected from fields, markets, and kitchens in Accra, Ghana, and over 300 soil and irrigation water samples were collected. All samples were analysed for E. coli, human adenovirus and norovirus using standard microbiological procedures. In addition, almost 700 participants including farmers, food vendors, and consumers were interviewed and observed to assess critical exposures associated with the transmission of faecal pathogens.The results showed that irrigation water was significantly more contaminated than farm soil, though exposure to soil was found to pose the key risk to farmers due to hand-to-mouth events. Over 80% of produce samples were found contaminated with E. coli, with street food salad being the most contaminated (4.23 Log E. coli/g), and that consumption of salads did not meet health standards. Risk factors identified for produce contamination included farm soil contamination, wastewater use for irrigation, poor hygiene, and operating with a hygiene permit. Awareness of the source of irrigation water was low, but despite the high awareness of health risk, consumers did not prioritize health indicators when buying produce from vendors. Similarly, farmers' awareness of health risk did not influence their adoption of safer farm practices. The study recommends the promotion of interventions that would result in more direct benefits to producers and vendors, together with hygiene education and inspection, hygiene certification and enforcement of food safety byelaws in order to increase the uptake of the multi-barrier approach. 4PhD related documents 2014:

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“…People handaling wastewater and sludge including wastewater and sludge treatment plant workers, people transporting sludge as well as farmers applying wastewater and sludge to land and wastewater applied mine workers can be exposed to helminth ova and larvae directly during their work (Seidu et al, 2008;Ackerson and Awuah, 2012). This group has higher (40%) rate of helminth infections than indirectly exposed groups (Ensink et al, 2005;El Kettani and Azzouzi, 2006;Trang et al, 2007;The World Bank, 2010). In the directly exposed group, hookworm infection is found to be more common (Ensink et al, 2005;Ensink et al, 2008).…”

Section: Potential Public Health Risksmentioning

confidence: 93%

“…This group has higher (40%) rate of helminth infections than indirectly exposed groups (Ensink et al, 2005;El Kettani and Azzouzi, 2006;Trang et al, 2007;The World Bank, 2010). In the directly exposed group, hookworm infection is found to be more common (Ensink et al, 2005;Ensink et al, 2008). This could be due to the transmission mode (oral ingestion and skin penetration) of hookworms.…”

Section: Potential Public Health Risksmentioning

confidence: 93%

“…It has been estimated that 5.0 × 10 6 ha of agricultural land is irrigated with raw wastewater (Carr, 2005), and up to 42% of sludge produced globally from wastewater treatment process is being used as fertilizer (Kelessidis and Stasinakis, 2012). Since a single viable ovum has the potential to cause infections in an individual, the health risks can be high for people coming into contact with wastewater and sludge in areas where helminth infections are endemic especially in the developing countries (Ensink et al, 2005;WHO, 2006).…”

Section: Quality Controlmentioning

confidence: 99%

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Detection of viable hookworm ova from wastewater and sludge

Gyawali¹

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Infectious helminths are a worldwide major public health problem. In terms of morbidity, approximately 3 × 10 9 people are infected by soil-transmitted helminths (STHs) influencing rates of malnutrition and failure to thrive. All of this increases the global disease burden (GDB) by up to 5.9 × 10 6 Daily Adjusted Life Years (DALYs). Helminth infections are more often seen as a major public health issue for developing countries however, concerns have been expressed in many of the developed nations because of the increased use of treated wastewater and sludge with no clear way of knowing the infection potential that can be attributed from such water.Guidelines have been established to minimise the potential public health risk associated with wastewater and sludge reuse. For example, the WHO guideline specified ≤ 1 ova (Ascaris lumbricoides) per L liquid (wastewater) or 4 g dry solid (sludge) for unrestricted use. Various wastewater treatment processes have been recommended to remove the helminths ova from wastewater depending upon its reuse. However, detection methods used to quantify viable helminths ova from wastewater has limitations. Therefore there is always a potential public health risk associated with reuse of wastewater and sludge.In this research, a real-time PCR method was developed. The new PCR method is rapid and specific. The method was found to be able to detect less than one ovum in one litre treated wastewater and approximately four ova in one litre raw wastewater and ~ 4 g sludge.The real-time PCR method was modified to a quantitative PCR (qPCR) method and further used to quantify hookworm ova from wastewater and sludge. The qPCR had estimated an average of 1.1, 8.6 and 67.3 ova for treated wastewater that was seeded with 1, 10 and 100 ova, respectively. The gene copy numbers obtained for 1, 10 and 100 ova by qPCR varied significantly (P < 0.05) within the tested samples indicating that absolute quantification of ova may not be accurate. Despite the difficulty quantifying accurate numbers of hookworm ova, the lower limit of quantification (LLOQ) of the qPCR method was 30 gene copies. This was a lot less than the gene copies produced by one ovum. Therefore, the qPCR method has potential to use for complying with wastewater guidelines.. iiAlthough the overall aim of this research was to develop a sensitive and specific method for quantitative detection of viable hookworm ova from wastewater, the importance of recovering the ova from wastewater and sludge samples for accurate detection was identified. While determining appropriate recovery rates was not an aim of this research, a suitable method that could be used to standardise research outcomes for further study was established. Therefore, ova recovery rate by different rapid methods was evaluated for further experiments. The result indicated that the ova recovery rate was higher for the treated wastewater (0.2 -50%) than the raw wastewater (0.3 -35%) and sludge (0.02 -4.7%) samples. A significant difference (P < 0.05) was observed between...

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High risk of hookworm infection among wastewater farmers in Pakistan

Cited by 61 publications

References 15 publications

Incidence and Risk Factors of Hookworm Infection in a Rural Community of Central Thailand

Incidence and Risk Factors of Hookworm Infection in a Rural Community of Central Thailand

Wastewater use in urban agriculture: an exposure and risk assessment in Accra, Ghana

Detection of viable hookworm ova from wastewater and sludge

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