Cholera outbreak investigation — DTM&H MCQ

Correct answer: D — Provide safe water, rehydration points and surveillance

Provide safe water, rehydration points and surveillance (D) is correct because the vignette describes a point source cholera outbreak (sudden profuse watery diarrhoea, deaths, clustering around one water vendor after a borehole pump fails). The immediate priority in such outbreaks is prompt case management with oral or intravenous rehydration to prevent death, combined with rapid restoration of safe water supply, chlorination or water treatment, and case based surveillance to track spread and target the response. This matches UK and international outbreak control guidance, which stresses that a water and sanitation intervention plus rehydration access saves the most lives fastest, without waiting for laboratory confirmation of Vibrio cholerae. Deaths from cholera occur from dehydration within hours, so speed of rehydration and safe water provision is the single most important determinant of outcome. Why the other options are wrong: C. Close schools as sole measure: this does not address the transmission route (contaminated water from the vendor) or treat existing cases, so it fails to reduce mortality or interrupt the epidemic. E. Mass albendazole campaign: albendazole targets soil transmitted helminths and some protozoa, not toxin mediated bacterial diarrhoea such as cholera, so it has no role in this clinical picture. A. Start malaria spraying: indoor residual spraying targets mosquito borne malaria transmission and is irrelevant to a waterborne diarrhoeal outbreak. B. Wait for culture before action: delaying intervention for stool culture or PCR confirmation allows ongoing transmission and preventable deaths; outbreak control must start on clinical and epidemiological suspicion. Key point: In suspected cholera outbreaks, treat clinically and secure safe water and surveillance immediately, do not delay control measures for laboratory confirmation.

Reference: GOV.UK/UKHSA, Cholera: guidance, data and analysis, 2024 (https://www.gov.uk/guidance/cholera); WHO, Cholera outbreak: assessing the outbreak response and improving preparedness