Researchers can determine whether or not you are susceptible to traveller’s diarrhoea (also called Delhi Belly) by looking at your saliva.
A recent study from the Boston University School of Medicine (BUSM) found the presence of a certain protein called histatin-5 can predict whether or not you’re resistant to the disease.
The discovery raises the possibility of creating a a powder from the protein that could be taken by those travelling to protect their gut from the bacteria.
Researchers can determine whether or not you are susceptible to traveller’s diarrhoea by looking at your saliva
Protecting the small intestine
Traveller’s diarrhoea is defined as passing three or more loose/watery bowel motions within 24 hours.
There are over a billion cases a year, of which tens of thousands are thought to be due to the disease.
To find out whether the histatin protein can prevent infection, the researchers grew mini small intestines in petri-dishes. Some of these samples, called organoids, also received a dose of the protein, which is found naturally in saliva.
The samples were then infected with the bacteria enterotoxigenic Escherichia coli (ETEC), which triggers traveller’s diarrhoea.
The virus works by infecting the arm-like structures that line the intestine, called ‘pili’.
Those organoids with histatin-5 had significantly fewer bacteria on their pili than those without the protein.
‘We found that the protein histatin-5 present in human saliva stiffens the pili of ETEC, preventing the bacteria from effectively adhering to the small intestine,’ Esther Bullitt, PhD, associate professor of physiology and biophysics at BUSM, explained.
In the intestine samples with histatin-5, there were significantly fewer bacteria present on the pili than those without the protein
‘If they can’t attach, they simply can’t cause disease.’
The potential of saliva
The study notes that the protective effects of saliva have not been recognised until now.
The researchers say the mouth might act as an screen against bacterial infection, and that’s why only a significant number of ETEC can cause the disease.
They now think a histatin-5 powder could be synthesised that will boost the gut’s stock of this important protein.
They hope that other proteins could be discovered in the saliva with similar beneficial properties.
‘We believe that our data represent the first example of a new paradigm in innate immunity: the contributions of salivary components to preventing infection.
‘This research opens an untapped avenue for prevention of enteric infectious diseases through the targeted use of naturally occurring components of saliva.’
WHAT IS TRAVELLER’S DIARRHOEA?
Travellers’ diarrhoea is defined as passing 3 or more loose/watery bowel motions in 24 hours.
Only around 3 per cent of cases have 10 or more bowel motions daily. It may be accompanied by any of the following symptoms: fever, abdominal cramps, urgent need to pass bowel motion, nausea or vomiting.
Most cases occur in the first week of travel and are mild, i.e there are no other symptoms and it does not disrupt normal activities. On average, symptoms last for 3-5 days and most cases resolve without any specific treatment.
When travellers’ diarrhoea is associated with additional symptoms and this leads to an interruption of normal activities, it is classed as moderate to severe.
Travellers’ diarrhoea can be caused by many different organisms including bacteria, such as E. coli and Salmonella, parasites such as Giardia, and viruses such as norovirus.
All these organisms are spread through eating/drinking contaminated food/water or contact between the mouth and contaminated hands, cups, plates etc.
Loose bowel movements can also result from a change in diet including, for example, spicy or oily foods.
Source: Fit For Travel