On The Other Hand: New SHARE-Funded Research From Bangladesh

An icddr,b study has found that both the left and right hands of Dhaka commuters are equally contaminated with faecal bacteria. Although there is a cultural stigma around using the left hand in Bangladesh, the study suggests that cultural practices do little to stop the spread of germs, as both hands are equally contaminated.

The World Health Organization estimates that at least 2.2 million people die each year as a result of diarrhoea and other gastrointestinal diseases. According to the Lancet, washing hands with soap can reduce the risk of diarrhoeal diseases by 42–47% and interventions to promote hand washing might save a million lives a year globally.

In 2016, Dr M Sirajul Islam, icddr,b emeritus scientist, along with colleagues from icddr,b and the London School of Hygiene and Tropical Medicine, UK, analysed 900 hand washing samples from Dhaka commuters, from both their left and right hands, during one year to cover all three Bangladesh seasons (winter, summer and rainy seasons). The study measured the levels of four faecal bacteria on the hands of commuters.

The results, recently published in the journal Transactions of the Royal Society of Tropical Medicine and Hygiene, revealed that there were no statistically significant differences in the levels of faecal bacteria on commuters’ left and right hands. The results contradict the belief that the left hand is more prone to faecal contamination from using lavatories in Bangladesh and stressed the importance of washing both hands together.

“It was surprising to find such high rates of bacterial contamination of faecal origin on hands despite self-reported hygiene practices,” reported Dr Siraj. “This may indicate a higher risk of pathogens being transmitted to find and infect new hosts via a vicious circle of transmission in a community. The simpler and better way to break this circle is to wash hands with soap or other detergent to achieve a clean environment and to prevent person-to-person, person-to-surface and surface-to-person transmission  resulting in the reduction of spread of infectious diseases.”

However, Dr Siraj acknowledges that more research is required to gain a better understanding of this problem among the commuting population of Bangladesh. He has suggested that the next study should collect information on additional factors such as socioeconomic status, personal hygiene and duration of stay in vehicles by commuters. Such research could be used to develop appropriate prevention and hygiene strategies in a population commonly affected by gastrointestinal illness.

Dr Shah M Faruque  director genomics laboratory research at icddr,b and senior author of the study, confirms that its findings could make an important contribution to reducing transmission of faecal bacteria and diarrhoeal pathogens in Bangladesh.

“Public health interventions are clearly needed to reduce the prevalence of faecal contamination and transmission in Bangladesh,” emphasises Dr Faruque.“These findings aim to guide future interventions in the public health so as to reduce the spread of infectious diseases targeting policy-makers in government, soap companies and NGOs.” More and better-designed awareness and education campaigns are required to promote the impact of washing hands on diarrhoea and acute respiratory infections, both of which are leading causes of death in low-income countries.

The study was funded by the UK Department for International Development (DFID), through the SHARE Consortium led by the London School of Hygiene and Tropical Medicine.

This news story was first published by icddr,b.