Outbreak of Diarrhea Caused by a Novel Subtype During British Military Training in Kenya.

BACKGROUND

We report clinical, epidemiological, and laboratory features of a large diarrhea outbreak caused by a novel subtype during British military training in Kenya between February and April 2022.

METHODS

Data were collated from diarrhea cases, and fecal samples were analyzed on site using the multiplex polymerase chain reaction (PCR) BioFire FilmArray. Water was tested using Colilert kits (IDEXX, UK). DNA was extracted from feces for molecular characterization of , , , and genes.

RESULTS

One hundred seventy-two of 1200 (14.3%) personnel at risk developed diarrhea over 69 days. One hundred six primary fecal samples were tested, and 63/106 (59.4%; 95% CI, 0.49%-0.69%) were positive for spp. Thirty-eight had spp. alone, and 25 had spp. with ≥1 other pathogen. A further 27/106 (25.5%; 95% CI, 0.18%-0.35%) had non- pathogens only, and 16/106 (15.1%; 95% CI, 0.09%-0.23%) were negative. was detected in 58/63 (92.1%) spp.-positive primary samples, but the others were not genotypable. Twenty-seven specimens were subtypable; 1 was subtype IeA11G3T3, and 26 were an unusual subtype, ImA13G1 (GenBank accession OP699729), supporting epidemiological evidence suggesting a point source outbreak from contaminated swimming water. Diarrhea persisted for a mean (SD) of 7.6 (4.6) days in spp. cases compared with 2.3 (0.9) days in non- cases ( = .001).

CONCLUSIONS

Real-time multiplex PCR fecal testing was vital in managing this large cryptosporidiosis outbreak. The etiology of a rare subtype emphasizes the need for more genotypic surveillance to identify widening host and geographic ranges of novel subtypes.