Zika virus

Zika virus and Pregnancy

It is all over the news so it would be astounding if you have not heard a bit about it already. But what are the facts (without having to read a scientific article)?

Zika virus info sheet
Zika one-page summary
Qld Health_Notice_Zika– useful information for clinicians and the general public

What is the Zika virus?

– It is a virus in the Flavivirus family, meaning it is closely related to dengue
– It was first discovered in rhesus monkeys in the Zika Forest in Uganda back in 1947
– It is spread by a specific type of mosquito of the Aedes family
– The first significant outbreak of Zika virus in humans was in the Yap Island of Micronesia in 2007, where 75% of the population was infected
– The Zika virus is now found in many countries in Central and South America and in the Pacific Islands

What symptoms does Zika virus infections cause?

– The incubation period (from first infection to symptoms) is 3-12 days
– Symptoms last for 2-7 days
– 80% of people infected with Zika virus have no symptoms
– In the 20% of people who do have symptoms, it is only a mild illness that include cutaneous maculopapular rash, low grade fever (less than 38 degrees Celsius), joint pain/arthralgia especially of small joints of hands & feet with possible swollen joints, conjunctivitis, headache, muscle pain/myalgia, post-infection asthenia
– Rarely, people may experience disgestive complaints (abdominal pain, diarrhoea, constipation), mucous membrane ulcerations, pruritus
– In the outbreaks in the Pacific, it was noticed that there was an increase in autoimmune and neurological diseases such as Guillain-Barre
– In mice studies, the Zika virus has been shown to replicate in neurons causing neuronal destruction so nerve damage in humans is a real possibility

What effect does the Zika virus have on pregnancy?

– The Zika virus is suspected of causing congenital anomalies when the pregnant mother is infected with the Zika virus during pregnancy
– In the recent outbreak of Zika virus in Brazil, it was noticed that there was a sudden increase in cases of microcephaly (small brains) in newborns – of the first 35 cases, 26 had documented that the mother had developed an illness with a rash during the pregnancy
– No causal link between Zika virus infection and microcephaly has yet been established
– However, it is known that Zika virus causes neuronal damage so it is biologically plausible
– Also, scientific studies may take some time before a causal link can be firmly proven and sometimes it is not possible to wait for this certainty before acting to protect the community from a potential threat
– There has been some suggestion that the microcephaly was caused by some other agent such as chemicals in the water or a new vaccine or some other government conspiracy – regardless, until it is proven that it is not Zika virus, best to avoid the virus infection for now

I’m pregnant, how will I know if I am infected?

– There are no cases where a person was infected in Australia – all cases have been people infected overseas who then travelled back to Australia
– The Aedes mosquito that transmits the Zika virus is only found in North Queensland so other areas of Australia can feel quite safe – if still anxious, avoid mosquito bites by using the usual protective measures
– Testing for infection can now be performed through public health laboratories in Australia through a blood test
– Even if infection is confirmed, there is no treatment – the pregnancy will just be monitored more closely with more ultrasounds looking for the congenital anomalies that might indicate an infection
– There is no vaccine for Zika virus
– It is thought that once infected with Zika virus, a person is protected from future infections