Breaking news: Zika virus update. St.Emlyn's.

Infectious disease outbreaks can sometimes appear to spread like bush fires. We are just about taking stock as we emerge from the Ebola outbreak in West Africa where the incidence of cases has progressively decreased, then we are arguably just about getting to grips with the MERS outbreak in the Middle East and South Korea. Don’t relax though as a new outbreak already looms on the horizon: the Zika virus.

As I sat down to type this blog post, one of the first cases of Zika virus infection has just been diagnosed in Europe within the past few hours. A Danish national has indeed tested positive for the mosquito-transmitted Zika virus after travelling to South America.

As an emergency physician, chances are that you might not have heard of this exotic and somewhat mysterious illness so I thought it was time for a StEmlyns update…

What is the Zika?

The Zika virus (ZIKV) was first isolated in a monkey and described in 1947 in East Africa. It was named after the rain forest were it was first discovered.

As with Ebola, which we have known since 1976 or MERS which is caused by a mutated coronavirus (family of viruses we have known for about a century), ZIKV is nothing new.

The virus is a member of the flavivirus genus from the Flaviviridae family and is transmitted by the Aedes mosquitoes, common in urban environment. We also know this family of mosquitoes fairly well as they transmit Dengue or the yellow fever too.

Symptoms:

The majority of patients infected get no symptoms or mild symptoms only. The disease is short-lived and symptoms are atypical:

fever
arthralgias/myalgias
skin rash (maculopapular)
headaches
eye pains
conjunctivitis

You can see from the symptoms that they are not very specific and you should be putting them in context along with a travel history.

The symptoms are similar to Dengue or malaria which often are co-circulating with ZIKV.

Serious complications or deaths are uncommon so it was considered so far as a rare and seemingly benign disease.

The infection got media attention because of the birth defects that was observed accompanying the infection outbreak and the possibility of developing Guillain-Barre syndrome in some rare cases.

Transmission:

As mentioned above, transmission is via the female Aedes mosquito. What is unusual is whilst the Anopheles mosquito (that transmits malaria) is mostly nocturnal, the Aedes mosquito feeds daytime.

Aedes Aegypti mosquito from wikipedia — Aedes Aegypti mosquito from Wikipedia

The mosquito is not indigenous in Europe so transmission via this route is technically excluded. If you have travelled by plane to and from South America or Africa, you will know that the interior of planes are fumigated once the doors are closed and before take off. This is to ensure that mosquitoes are not imported to Europe.

The incubation period is variable and ranges from 3 to 12 days (two weeks is easier to remember).

Just like with Ebola, we also know that the Zika virus is present in bodily secretions (like semen and vaginal secretions, amniotic fluid etc) well after the disease. There is published evidence that some cases have spread via sexual trasmission but this is not the main way of transmission.

Countries at risk:

As mentioned above, Zika was discovered in Africa but very few outbreaks have been documented.

The current outbreak however is linked to locally-acquired cases in Central and South America and the Caribbean (the main countries being Brazil, El Salvador, Guatemala, the Dominican Republic etc.). For a comprehensive list of countries affected please click here.

Note that French Polynesia (located in the Pacific Ocean) and Cape Verde (located in the Atlantic Ocean), which are countries at risk are not in America.

Again, the WHO provides weekly updates on the list of affected countries so make sure you consult their website if any doubt.

So what is the fuss all about?

It’s interesting to see how most of the infectious diseases outbreaks in the 21st Century have received loads of media coverage. This is very good for us as information sharing is essential to be able to keep up with emerging and re-emerging infections worldwide, although it may also cause lots of anxiety (for patients and clinicians). Only a minority of infectious disease events will require your full attention.

This particular outbreak got global media attention as Zika infection shows a correlation with birth defects, namely microencephaly. Brazil for example saw 20 times more microcephaly cases in 2015 than normal.

If you have a look at the list of countries at risk, you will see that most of them are common holidays destinations for European travellers seeking the warm beaches. With globalisation and the spread of low cost flights, you can easily imagine imported cases to the UK.

Also, the summer Olympics will be held in Brazil in less than four months from today…

What should you do as an emergency physician?

take a travel history from patients with a fever or history of fever

This should include not only the country where they stayed but the local environment (five-star hotel with air conditioning versus the bush), length of time spent away, transit flights, use of repellent and prophylaxis against malaria etc.

know you epidemiological map

I have to confess I am very bad at the geography of Central and South America (maybe an excuse for a new holiday destination?) and I have no trick to help you out. I however believe that in the 21st century, it is perfectly acceptable to use the internet to locate a country during a patient consultation.

common things are common

Malaria is more common, co-circulates in most areas where ZIKV is endemic and carries a higher fatality rate. Always perform a malarial screen on these patients. As mentioned above, ask about malaria prophylaxis as incomplete prophylaxis might result in cases of malaria.

work collaboratively with your local public health, virology/microbiology, infection prevention and control teams

In Virchester, we have a long tradition of successful collaboration working with the above specialties following the Ebola and MERS outbreaks. We are currently drafting a local diagnostic pathway based on clinical presentation and travel history in order to facilitate diagnosis in patients presenting to ED.

be prepared to be asked

It’s entirely possible that a patient may turn up in your ED worried about ZIKA. Be kind and understanding. Help them understand and if they are genuinely at risk and pregnant then facilitate them to be seen by the obstetric team for further advice and follow up.

use universal precautions of hygiene in your ED

There are no known cases of direct one touch transmission of Zika but I like to use occasions like this and remind all my staff to use gloves and barrier nursing on all patients they attend. Hand hygiene is easy and we have running water in our EDs so there is no valid excuse for not washing your hands before and after patient contact!

Janos

@baombejp on Twitter

Further reading.