Domestic pigs could be fundamental in the adoption of a vaccine programme to reduce the prevalence of Japanese Encephalitis in Bangladesh, an analysis by a Gonville & Caius College postgraduate student has shown.

Dr Mariana Perez Duque (Epidemiology PhD 2022) used data gathered in collaboration with researchers in Bangladesh to assess the challenge posed by Japanese Encephalitis. This is a viral infection, which affects the neurological system, that is spread through mosquito bites. The research could also inform work on other emerging vector-borne diseases.

“The mosquito circulates in areas where three billion people are exposed, almost half of the world’s population,” says Mariana, a medical doctor and consultant in public health medicine in her native Portugal before she moved to the University of Cambridge with a Gates Scholarship.

“Why Bangladesh? Bangladesh is one of the countries where Japanese Encephalitis is endemic, but they don’t have a vaccine programme implemented. The transmission is very heterogenous across the country, so I’m using on data from infected people and animals to better understand the spread.

“The transmission cycle of this virus includes water birds and pigs. Several communities in Bangladesh raise pigs in their back yards. Therefore, we want to assess the role of pigs in disease transmission.”

Vaccinating pigs could be part of a multi-factor approach to reduce the spread of the disease, one of the leading causes of childhood encephalitis in Asia.

“We are working with all this data to understand how this disease spreads, to map the risk and to inform the Ministry of Health, who are currently very interested in implementing a new vaccine programme,” Mariana adds.

“A vaccine exists and works. A lot of countries have included it in their childhood immunisation programmes. We want to use data to investigate if including the Japanese Encephalitis vaccine in the vaccine programme in Bangladesh would be helpful.”

A presentation of this work earned Mariana the best poster award at the Cambridge Infections Diseases Annual Symposium last month.

She started her PhD on chikungunya in South and Southeast Asia, another emerging vector-borne disease. There is currently an ongoing epidemic in Brazil and Paraguay, with several thousands of people infected.

Mariana, who is supervised by Dr Henrik Salje in the Pathogen Dynamics Group in the Department of Genetics, is also focused on Japanese Encephalitis. Vector-borne disease research is only going to become more topical, she says.

“Climate change will increase impact the spread of disease and of mosquitoes and ticks, which is an area we should learn about now so we can be better prepared in the future,” Mariana adds.

“With increasing temperature and extreme weather events, it’s possible that mosquitoes will be established in new places, at higher latitudes.

“What we know now as temperate regions are becoming more tropical regions, specifically mosquitoes capable of transmitting viruses such as chikungunya and dengue have been established in the south of Spain, south of France, Italy and Portugal. We will see more outbreaks of these diseases in Europe in the next years.”

In the future she wishes to combine her research with the public health experience gained from her positions in Portugal, the European Centre for Disease Prevention and Control, and Médecins Sans Frontiers.

She says: “I’d like to be in the field and do research at the same time, building the bridge between field-based organisations, governments and academia. There’s a lot of people already doing each part individually; I want to be a catalyser and bring everything together.”