Showing people germs under a microscope before teaching them about hand washing and other good health practices improves hygiene. That is the central finding of a new randomised evaluation conducted in rural Pakistan by Daniel Bennett, Asjad Naqvi and Wolf Peter Schmidt. Their study of a novel hygiene education programme called Microbe Literacy finds that the effects of an intervention that only takes three hours persist for at least 16 months.

The research findings, which are published in the July 2018 issue of the Economic Journal, also reveal that people with strong beliefs in Unani, the predominant form of traditional medicine in Pakistan, show no improvement in hygiene or health as a result of the intervention.

This finding suggests that Unani beliefs may prevent people from accepting and responding to hygiene messages. Although more research is needed, there may be a trade-off between traditional and modern medicine. The implications of this trade-off may be profound since billions of people throughout the world follow some form of traditional medicine.

The researchers note that as a major cause of infant and child mortality, diarrhoea is an urgent public health challenge in many developing countries. Improving hygiene and sanitation can save lives, but policy-makers have struggled to convince people to change their behaviour.

In the Microbe Literacy programme developed by the Microbe Literacy Initiative, participants use microscopes to view microbes from their environment before receiving a hygiene lesson in washing hands and avoiding infection.

For many poor people in developing countries, the microscope demonstration is their first opportunity to visualise microbes that are otherwise invisible. Seeing these organisms makes health messages that are predicated on the germ theory of disease more credible.

The authors collaborated with Microbe Literacy Initiative to evaluate the programme among 4,032 female adult literacy class participants. They randomised these classes to either receive the full Microbe Literacy programme, only hygiene instruction (without the microscope demonstration) or no programming.

Since hygiene is hard to measure, surveyors visually inspected the cleanliness of participants’ hands. Microbe Literacy participants were 0.14 points cleaner (on a three-point scale) on average after three months. This effect persisted and even strengthened after 16 months.

Based on this promising evidence, Microbe Literacy Initiative is looking to scale up the programme and introduce it in other settings, including India, Nicaragua and elsewhere in Pakistan.

The authors also find an intriguing pattern related to the use of traditional medicine. Unani medicine is the predominant form of traditional medicine in Pakistan. It offers an alternative view in which imbalances within the body, rather than invisible pathogens, cause diarrhoea.

Unani beliefs, which echo the tenets of Ayurveda, traditional Chinese medicine and other traditional medical systems, may contradict hygiene promotion and other disease prevention messages.

To test this hypothesis, the authors categorised participants according to the strength of their Unani beliefs. They find that:

• Participants with weak Unani beliefs show large and significant impacts on hygiene, which translate into improvements in child health and weight-for-age.

• By contrast, participants with strong Unani beliefs show no improvement in hygiene or health.

• Other individual attributes like income and education cannot explain this pattern.

Learning, Hygiene, and Traditional Medicine’ by Daniel Bennett, Asjad Naqvi and Wolf-Peter Schmidt is published in the July 2018 issue of The Economic Journal.