Bolivian haemorrhagic fever — DTM&H MCQ

Correct answer: D — Bolivian haemorrhagic fever (Machupo virus)

The correct answer is D, Bolivian haemorrhagic fever (Machupo virus). This woman's rural farming exposure in Bolivia, incubation period of around 10 days, and combination of fever, headache and petechial rash are classic for Machupo virus infection, an arenavirus classed by UKHSA as a high consequence infectious disease (HCID) endemic to a defined geographic focus in the Beni department. Human infection with both viruses occurs after exposure to infected wild native rodents in Bolivia, chiefly Calomys callosus, and agricultural work in fields and farm shelters is the principal risk activity. The gradual onset of fever and headache progressing towards haemorrhagic features (petechiae, mucosal bleeding) with the rural farming exposure history in the correct endemic country makes this the most likely diagnosis over the geographically or clinically mismatched alternatives. Why the other options are wrong: B. Dengue haemorrhagic fever: Dengue is transmitted by Aedes mosquitoes in urban and peri-urban settings, not specifically linked to rural farming exposure, and while it causes fever and petechiae, it is not the diagnosis specifically anchored to Bolivian rodent-exposed farmland. A. Rocky Mountain spotted fever: This is caused by Rickettsia rickettsii transmitted by ticks in North, Central and parts of South America, but it is not the classic teaching association for rural Bolivian farming exposure and Calomys rodent contact described here. E. Meningococcal septicaemia: This typically presents more acutely (hours, not 10 days post-travel) with rapidly progressive purpura, neck stiffness and shock, and has no specific link to Bolivian travel or rodent exposure. C. Hantavirus pulmonary syndrome: Hantavirus also has rodent exposure but characteristically causes prodromal illness followed by pulmonary oedema and respiratory failure, not a petechial rash picture, and is not the specific Bolivian farming vignette answer. Key point: Fever, headache and petechial rash 7 to 10 days after rural farming exposure in Bolivia points to Machupo virus (Bolivian haemorrhagic fever), an arenavirus HCID acquired from Calomys callosus rodent contact in the Beni region.

Reference: UK Health Security Agency (GOV.UK), 'Haemorrhagic fevers in Bolivia: origins, reservoirs, transmission and guidelines', https://www.gov.uk/guidance/haemorrhagic-fevers-in-bolivia-origins-reservoirs-transmission-and-guidelines