Virologist warns Zika is not like HIV

DW: The Zika virus is spreading to almost all countries in North- and South America. Can the virus be transmitted directly from one person to another?

Professor Jonas Schmidt-Chanasit: It is mainly transmitted through mosquitoes. The Zika virus can also be sexually transmitted, but that's not what usually happens. One issue however is that the majority of those infected will never get ill and don't know they're carrying the virus. That makes the sexual transmission a little more likely.

You can't catch Zika in the ways that Ebola spread [in western Africa]: touching or kissing an infected person or via pathogens transmitted through the air. We shouldn't compare Zika with HIV or Ebola, so people don't get the wrong idea and spread hysteria by saying Zika is the new HIV.

Zika is clearly a "mosquito virus." It has adapted to mosquitoes and is usually not in contact with humans in its natural environment, the jungle. Unlike HIV, it hasn't adapted to humans and to being transmitted from one person to another.

Is it a blood-borne disease?

A transmission via blood transfusion is possible, just like with Dengue fever, which is related to Zika. Of course blood products in high-risk regions need to be tested now to prevent that from happening. Infected mothers can also pass on the virus to their babies during nursing. But those are not the main transmission routes that affect millions of people.

What role does the direct person-to-person transmission play in the spread of Zika?

The more cases there are, the more interesting these other, usually less significant transmission routes will become. If there are millions of such cases, we won't be able to ignore such transmission routes. It's being researched, and we have to continue researching it: how often does it happen, how long is the virus detectable in sperm, et cetera.

But the potential for sexual transmission is not the aspect that I and my colleagues are most worried about. We are mostly concerned with how to protect pregnant women, how to rein in the virus, and how to go conduct an intensive fight against mosquitoes now.

How dangerous do you think the virus is?

It has hit us pretty unexpectedly. The Zika virus has surfaced from the jungle and given us a pretty good fright. Especially the birth defects in infants are dramatic. Many of the babies don't survive. That, and the neurological damage associated with the infection in adults, is what worries me.

Jonas Schmidt-Chanasit is a doctor and virologist at the Bernhard Nocht Institute for Tropical Medicine in Hamburg.