According to recent research from the University of East Anglia, the bacteria in your stomach may have an impact on how severe a diarrheal illness is.

Every year, cryptosporidiosis causes over 100,000 deaths, most of which are in children under five. It also affects experimental models, and a recent study that was published in the journal Science indicates that the more severely affected are large species, such as primates, whose guts contain fewer varieties of bacteria.

It reveals that introducing more diverse gut bacteria can improve outcomes - including reducing diarrhoea and the potential for the disease to spread.

The team, led by Prof Kevin Tyler at UEA's Norwich Medical School, say that diet, probiotics and faecal transplant therapy could help target the disease by improving gut bacteria in people and experimental models. Prof Tyler said: "The vast majority of infections and deaths happen in low-income countries, but outbreaks also occur in the UK and elsewhere in Europe.

"In the UK, the disease is currently re-emerging and cases this year are increasing dramatically, suggesting the disease is currently epidemic. There are no human vaccines and only one drug licensed for human use, which is not effective for many who are affected.
So, understanding what can improve outcomes is critical to tackling outbreaks.

"We wanted to know whether some of the variations in symptoms might relate to the make-up of an infected person or experimental models gut bacteria and whether that composition was in turn affected by having cryptosporidiosis."

The team collected all studies that had looked at the composition of gut bacteria in experimental models which were infected by cryptosporidium and for which the data had been made publicly available.

They compared these to answer questions about the significance of gut bacterial diversity and the effect of cryptosporidium infection.
Lead researcher Georgina Hurle, also from UEA's Norwich Medical School, said: "The Cryptosporidium parasite is one of several microorganisms that cause diarrhoeal disease. It affects both babies and new-born livestock and it can be contracted either from experimental models or from people.

Most people contracting cryptosporidiosis will recover naturally, but some people and experimental models will require treatment, suffer long-term consequences from the infection, and may even die.

The severity of the disease is known to be affected by prior exposure, so adults are generally less severely infected and recover better.

We also found that having and even introducing more diverse gut bacteria can improve outcomes, reducing diarrhoea and the potential for disease transmission.

Gut bacteria composition can be affected by diet, by consumption of probiotics and pre-biotics and by therapies like faecal transplant therapy.

Understanding the changes that accompany infections and outcomes provides an opportunity for such relatively affordable but novel therapies to target a disease for which very few interventions are currently available.

"This study is important in showing that these approaches may be effective at reducing disease severity in those affected and at-risk groups and populations."

'Microbiome diversity is a modifiable virulence factor for Cryptosporidiosis' is published in the journal Virulence.