Deadly snail

Biomphalaria glabrata, a tropical Ram’s Horn snail, plays a large role in the lifecycle of the parasitic disease, schistosomiasis / UNM

Scientists have moved a step closer to eliminating schistosomiasis, a deadly parasitic disease, by sequencing the genome of a tropical snail. The paper, published in Nature Communications yesterday, reveals the genome of Biomphalaria glabrata, known as the tropical Ram’s Horn snail, and may enable researchers to identify a way of disrupting the parasite’s life cycle.

“Sequencing and characterizing the genome of this snail has given us a lot of information into its biology,” said Coenraad Adema, Ph.D., Associate Professor at the University of New Mexico who was responsible for leading the study. “It has informed us on animal evolution and supports the drive to minimize the impact of infectious disease on global health.”

Schistosomiasis, also known as snail fever or bilharzia, infects snails early in their development and ‘takes over’ the organism, impacting reproductive and metabolic processes. The parasite then uses the snail as a host during their development to maturity. Once matured, the parasite escapes the snail and transfers into water, where it can infect humans.

The Ram’s Horn snail is a vital part of this development process. Without it, the parasite would be unable to reach maturity and thus would never be able to infect humans.

“Understanding the snail’s genome gives us many avenues to cut the snail out of this parasite’s lifecycle, which one day may lead to the elimination of this disease,” said Adema.

Snail fever is a very widespread problem. The World Health Organisation (WHO) reported that in 2015, 66 million people were treated for the disease and another 218 million received preventative therapies. More worryingly, the disease can be fatal; WHO estimates that 250,000 people die from schistosomiasis in sub-Saharan Africa alone each year.

One of the biggest problems in trying to prevent the spread of the disease is that it is exceptionally easy to become infected. Once the parasite has moved into the water, where it can survive for some time, it is capable of breaking through undamaged human skin to infect them.

“After malaria, this is the worst parasitic disease on the planet,” said Adema. “So, being able to do work that may help improve global human health outcomes it is a very important motivation for my research.”

This study is the result of a collaboration of more than 100 scientists from over 50 institutions. The research was supported by the NIH’s National Human Genome Research Institute, alongside several other research bodies. Many of the researchers involved now hope to utilise their knowledge of the snail’s genome to disrupt the parasite’s development process.

“This is an important contribution to better understanding infectious disease,” Adema said. “It also gives us information on regulation of gene expression, comparative immunology, embryology, general biology of snails, animal evolution, and many other things.”