Zika virus in pregnancy — DTM&H MCQ

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ModerateTropical viral infectionsZika virus in pregnancyDTM&H

A 30-year-old woman who is 10 weeks pregnant returns from Brazil with a mild fever, conjunctivitis, pruritic rash and arthralgia. She is concerned about fetal risk after mosquito bites. What is the most appropriate investigation?

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Correct answer: B — Zika virus PCR or serology according to timing, with obstetric follow-up

The correct answer is B, Zika virus PCR or serology according to timing, with obstetric follow-up. This patient has a classic Zika prodrome (low-grade fever, conjunctivitis, pruritic maculopapular rash, arthralgia) after travel to a Zika-endemic area (Brazil), which is exactly the group UKHSA advises should be tested: symptomatic returning travellers with a compatible illness. Because viraemia is short-lived, UKHSA guidance selects PCR (blood and urine) within the first 1 to 2 weeks of symptom onset and serology thereafter, with the result and gestation guiding referral to fetal medicine for serial ultrasound. Confirmed maternal infection in pregnancy warrants specialist obstetric follow-up because of the recognised risk of congenital Zika syndrome, including microcephaly, so timing-appropriate virological testing is the investigation that actually changes management. Why the other options are wrong: E. Widal test and stool culture: these investigate enteric fever (typhoid/paratyphoid), which does not explain conjunctivitis and pruritic rash and is not indicated by this exposure history. A. Thick blood film as the definitive fetal risk test: this diagnoses malaria, a relevant differential in febrile travellers, but it has no role in assessing Zika-related fetal risk and is not "definitive" for anything in this vignette. C. Urine microscopy for schistosome eggs: schistosomiasis has a much longer incubation and causes haematuria or Katayama syndrome, not an acute rash with conjunctivitis and arthralgia. D. Serum cryptococcal antigen: this screens for cryptococcal infection in immunocompromised patients, irrelevant to a healthy traveller with this presentation. Key point: In a pregnant returning traveller with fever, conjunctivitis, pruritic rash and arthralgia after exposure in a Zika-risk country, request Zika PCR or serology (timing-dependent) and refer for fetal medicine follow-up.

Reference: UKHSA, Zika virus: sample testing advice, GOV.UK (updated guidance), https://www.gov.uk/guidance/zika-virus-sample-testing-advice