Natural disasters can disrupt the microbiota balance

Poor hygiene conditions can disturb the intestinal microbiota and be responsible for persistent abdominal pain.


Every year, millions of people are victims of natural disasters. They then have to live in poor hygiene conditions and many suffer from persistent abdominal pain, similar to that caused by irritable bowel syndrome (IBS). A team of Malaysian researchers studied villagers affected by severe floods in 2014 in order to better understand the origin and long-term consequences of this abdominal pain.

Access to water is vital

Two hundred and eleven inhabitants of two villages in North-East Malaysia, Kok Keli and Kok Pasi, were included in this study. Near 38% experienced abdominal pain several months after the flood, and around half of them suffered from irritable bowel syndrome (IBS).  This abdominal pain was associated to higher anxiety, and patients with IBS had significantly more psychological difficulties. The scientists used questionnaires to assess the hygiene conditions in which the villagers lived after the disaster. The villagers with abdominal pain were the same faced with the worst hygiene conditions, especially regarding major problems to access clean water.  Floods directly contaminate water sources, but they can also limit access to toilets, and according to the WHO, open defecation is the “most anti-hygienic practice of all”, and it is known to be a major cause of water contamination.

Microbiota disturbance

Tests were performed to measure bacteria proliferation in the small intestine of volunteers. This small intestinal bacterial overgrowth (SIBO) might be the source of an impaired functioning or permeability of the intestine,  which in turn causes pain. Only 17 villagers had positive results, but they were those living in the very worst hygiene conditions. Finally, stool analysis of 73 volunteers revealed changes in the intestinal flora of symptomatic subjects. Fusobacteria was more abundant in people with abdominal pain whereas Bacteroidetes and Proteobacteria were more abundant in those who were more anxious. As these bacteria are known biomarkers for intestinal dysbiosis,  the researchers suggested that the use of probiotics might be useful to protect and restore the microbial balance of populations affected by natural disorders, although they pointed out that additional studies are necessary to validate the efficacy of such treatments.


Yusof N, Hamid N, Ma Z.F et al. Exposure to environmental microbiota explains persistent abdominal pain and irritable bowel syndrome after a major flood. Gut Pathogens 2017 ; 9 : 75