The British army in Kenya has reported a diarrhoea outbreak in Nanyuki camp that lasted three months
At least 172 people were affected by the outbreak.
The outbreak is the largest ever reported by the army globally.
It was partly traced to contaminated fresh water, collected from rivers, where the trainees swam in Nanyuki.
“All freshwater activity recreational sites were found to have evidence of faecal coliforms (bacteria),” the army said in a research paper.
Some of the germs could also have been picked from local restaurants.
Importantly, the army said it identified a subtype of a diarrhoea-causing parasite previously only found in farmed monkeys in China.
Although the outbreak took place in 2022, the announcement was made through a research paper published early this month.
The army explained that its personnel arrived in Nanyuki in early February 2022.
Following increasing reports of profuse watery diarrhoea among 1,200 personnel between February 11 and 13, an outbreak investigation was declared on February 15, 2022.
Over the next 69 days, until April, 172 personnel had diarrhoea.
“We describe the largest recorded point source outbreak of human cryptosporidiosis in Sub-Saharan Africa and the only such outbreak to affect British military personnel anywhere,” the researchers, who included the army medics in Nanyuki and in the UK, said.
Cryptosporidiosis is an infection that causes diarrhoea. It is caused by the Cryptosporidium parasite. Most people get the parasite after swallowing food or water tainted with stool. This includes swallowing water while swimming.
This parasite is known to circulate in both human and domesticated animal hosts in Kenya and has previously been reported in Nakuru. But this is the first time its monkey subtype is being reported in Kenya.
“Molecular characterisation of the gp60 gene unexpectedly demonstrated infection with a novel highly divergent Cryptosporidiosis hominis ImA13G1 subtype. As far as we are aware, there is only one other report of subtype family Im, found in farmed crab-eating macaques (type of monkey) in China infected with ImA13,” the report says.
Batuk said 15 separate water exposure sites were tested, including seven recreational sites and eight water bowsers in the training area.
“Domestic camp water contained no faecal contaminants, supporting our hypothesis of a point source outside the camp,” they said.
Environmental investigations showed raw sewage emptying into rivers utilised by soldiers for recreational activities such as swimming.
“The recreational water sources were implicated by exposure histories taken from those affected, supported by environmental observations of visible contamination of the implicated sources, where gross faecal coliform contamination of the water was confirmed by testing,” the researchers said.
Their paper, Outbreak of Diarrhea Caused by a Novel Cryptosporidium hominis Subtype During British Military Training in Kenya, is published in the Open Forum Infectious Diseases journal.
Cryptosporidiosis outbreaks are rarely reported in Sub-Saharan Africa, partly due to a level of population immunity in endemic areas, but limitations in testing, reporting, recording, and investigation of cases are also a factor.
“Real-time multiplex PCR faecal testing was vital in managing this large cryptosporidiosis outbreak,” the researchers said.
They called for more genotypic surveillance to identify widening host and geographic ranges of the novel parasite originally reported in monkeys in China.