Zika Virus: News and Views

Tuesday, 6 September, 2016

Introduction

Zika is a mosquito-borne infection caused by Zika virus (ZIKV), a member of the genus flavivirus and family Flaviviridae. It was first isolated from a monkey in the Zika forest in Uganda in 1947.

On 1 February 2016, it was declared that the cluster of microcephaly cases and other neurological disorders reported in Brazil, following a similar cluster in French Polynesia in 2014, constituted a Public Health Emergency of International Concern (PHEIC).

As surveillance for Zika virus infection improves, further cases are expected to be reported in affected regions (Pacific islands and countries of South America like Brazil) and previously unaffected countries, particularly in south and central America and the Caribbean, where the Aedes mosquito vector is present.

https://www.gov.uk/guidance/zika-virus-country-specific-risk

Zika Cases Diagnosed In The UK

ZIKV does not occur naturally in the UK. However, as of 21 July 2016, a total of 50 cases have been diagnosed in UK travellers since 2015.

Transmission

Zika virus is most commonly transmitted by the bite of an infected female Aedes mosquito, mainly Aedes aegypti. The Aedes aegypti mosquito is not present in the UK as the UK temperature is not consistently high enough for it to breed. After an infected mosquito bites a human, the first symptoms of Zika can develop in 3 to 12 days. Other means of transmission are from mother to foetus via the placenta and through sexual transmission.

Symptoms

The majority of people infected with Zika virus are asymptomatic. For those with symptoms, Zika virus causes a mild, short-lived (2 to 7 days) illness. Signs and symptoms suggestive of Zika virus infection may include a combination of the following:

  • - rash
  • - itching/pruritus
  • - fever
  • - headache
  • - arthralgia/arthritis
  • - myalgia
  • - conjunctivitis
  • - lower back pain
  • - retro-orbital pain

The symptoms of Zika are similar to dengue (caused by a related flavivirus) or chikungunya (an alphavirus), which are often co-circulating in areas where Zika virus is present. Laboratory testing is essential for the correct diagnosis.

Serious complications and deaths from Zika are not common. However Zika virus is a cause of microcephaly and other congenital anomalies (also referred to as congenital Zika syndrome) and Guillain-Barré syndrome.

Diagnosis

Zika virus RNA is only detectable in blood for a few days (5 days) after symptoms begin, whilst Zika antibodies often appear within a week of symptom onset
In urine it is detected for longer, 10-14 days
In semen it can be detected for as long as 62 days

Testing only occurs in patients who exhibit signs of infection either whilst in a country with active Zika virus transmission or within 2 weeks of travel

pregnant woman with current symptoms: serum, EDTA blood, urine
man with current symptoms whose partner is pregnant: serum, EDTA blood, urine
all other male and female patients with current symptoms: serum, EDTA blood, urine

Men or non-pregnant women who have never experienced symptoms suggestive of Zika virus infection do not require testing.

For suspected cases of Zika virus infection, send samples to Public Health England’s Rare and Imported Pathogens Laboratory (RIPL), via the local diagnostic laboratory.

Latest Guidance:

Information for primary care and clinicians has been jointly developed by PHE, Royal College of General Practitioners and the British Medical Association:

Zika virus infection: guidance for primary care

For the latest government advice:

https://www.gov.uk/guidance/zika-virus-travel-advice https://www.gov.uk/guidance/zika-virus#sex

https://www.gov.uk/guidance/zika-virus#pregnancy

Researched and written by Simantee Guha, Consultant Microbiologist, Bedford Hospital