Does Malaria Cause Diarrhoea? A Systematic Review

Malaria is a systemic febrile disease thatmay progress to prostration, respiratory distress,
encephalopathy, anemia, and death. Malaria is also an established risk factor for invasive
bacterial disease caused, in the majority of cases, by invasive enteropathogens and in
particular by non-Typhoidal Salmonella (NTS). Whilst various malaria-related pathologies
have been implicated in the risk of NTS bacteraemia in animal models, including
intestinal dysbiosis and loss of gut homeostasis, clinical evidence is lacking. As a first
step in gathering such evidence, we conducted a systematic review of clinical and
epidemiological studies reporting the prevalence of diarrhoea among malaria cases
and vice versa. Database searches for “plasmodium” and “diarrhoea” identified 1,771
articles; a search for “plasmodium” and “gastroenteritis” identified a further 215 articles.
After review, 66 articles specified an association between the search terms and referred
primarily, but not exclusively, to Plasmodium falciparum infections. Overall, between 1.6
and 44% of patients with acute malaria infection reported symptoms of diarrhoea (812 of
7,267 individuals, 11%) whereas 5–42% of patients presenting to hospital with diarrhoea
had an underlying malaria parasite infection (totaling 749 of 2,937 individuals, 26%).
However, given the broad range of estimates, a paucity of purposeful case control or
longitudinal studies, and varied or poorly specified definitions of diarrhoea, the literature
provides limited evidence to draw any firm conclusions. The relationship between malaria
and gastrointestinal disturbance thus remains unclear. Carefully designed case-control
studies and prospective longitudinal studies are required to confidently assess the
prevalence and significance of intestinal manifestations of malaria parasite infection.