Zika advice for Irish people travelling this summer

Medical matters: There is currently no medication or vaccine that can prevent the virus

It's been a few months since alarm bells sounded about the spread of the Zika virus throughout South America and the Caribbean. We now know more about the bug and its potential complications.

So I thought, with those planning summer holidays in mind, that a column looking at our latest knowledge would be timely.

Starting with the latest update from the Centre for Disease Control (CDC) in the United States, it appears the spread and impact of the Zika virus is wider than initially anticipated.

Dr Anne Schuchat, deputy director of the CDC, told reporters the type of mosquito in which the virus is carried is present in more US states than initially thought. She said what authorities were learning about the virus was "scarier than we initially thought".


The CDC has confirmed there is no longer any doubt the Zika virus causes babies to be born with abnormally small heads (microcephaly) and other severe brain defects. Evidence that put the matter beyond doubt includes finding genetic markers of Zika in the brain tissue and spinal fluid of babies with microcephaly as well as in the amniotic fluid that surrounds babies in the womb.

In a report published online by the New England Journal of Medicine, the CDC described how they relied on a seven-point checklist to establish if something can be called a cause of birth defects.

Although some 350 Zika infections have been identified in the US, none has been indigenous. In other words, all have been shown to have been contracted while the person was abroad. But mosquito season is on its way.

According to the director of the National Institute of Allergy and Infectious Diseases, the US is likely to see indigenous outbreaks of the Zika virus. Predicting what he called a "local outbreak", Dr Anthony Fauci said this was likely to involve scores of people. The Aedes aegypti mosquito, which primarily transmits the disease, is present in about 30 US states.

Neurological illness

Evidence is also hardening to link Zika virus with neurological illness in adults. Cases of meningoencephalitis, which is an inflammation of the brain and the covering around the brain and spinal cord damage due to myelitis, are occurring in a small number of people infected with Zika.

There has also been a spike in cases of Guillain-Barré syndrome in affected areas. The syndrome occurs when viruses attack the nervous system, causing temporary paralysis of the lower limbs as well as the chest muscles required for breathing.

It is worth noting, as the complications of Zika mount for a minority, most people infected with the virus remain asymptomatic.


In one study, only 19 per cent of those infected had symptoms that were attributable to Zika virus. The most common symptoms are a skin rash (seen in 90 per cent of patients), fever (65 per cent), joint pain or swelling (65 per cent), conjunctivitis (55 per cent), muscle pain (48 per cent), and headache (45 per cent).

There is currently no medication or vaccine that can prevent Zika, although there is hope of a first vaccine appearing in September.

The best way to prevent Zika while travelling in a Zika area is to avoid mosquito bites by wearing appropriate clothing, staying indoors, and using insect repellent.

Of particular importance for Irish holidaymakers is the CDC advice that pregnant women avoid unnecessary travel to areas with active Zika transmission.

This may include the US if official predictions turn out to be correct. For now, the warning applies to most countries in the Caribbean, South America and parts of Micronesia.

For men who have travelled to a Zika area and who have a pregnant partner, abstinence or condom use for the duration of pregnancy is recommended.

At present it is not known how long Zika can be sexually transmitted after exposure, as the virus may remain active in semen longer than it does in the bloodstream.

mhouston@irishtimes.com @muirishouston