In Brazil, case reports of microcephaly are up from just over 400 in 2014 (417 I think) to over 3,500 in 2015. 

Rates of microcephaly are climbing dramatically. The latest figures are here: http://oglobo.globo.com/sociedade/saude/em-uma-semana-casos-de-microcefalia-no-rio-aumentam-194-18512507

Non-lusophones can run the page through Google translate. 

Note that the cases of zika are not the only think climbing. The same mosquito also carries dengue, and dengue cases are also rising rapidly. Dengue can lead to dengue haemorrhagic fever, which is potentially fatal. 

So with the current accelerating climate change, we can expect both zika and dengue to reach new populations that have no immunity. And, of course, with high levels of tourism to poor countries with warm climates, there is the obvious danger to people from rich countries with cool climates. 

Nonetheless, the victims will be concentrated in poor countries that lack the infrastructure and resources to contain the epidemic. Just like ebola. 

http://oglobo.globo.com/sociedade/saude/em-uma-semana-casos-de-microcefalia-no-rio-aumentam-194-18512507

This is good question. It is not so dangerous. It initially causes a mild illness. There are no hospitalizations, and no deaths.

Zika virus is transmitted by daytime-active mosquitoes and has been isolated from a number of species in the genus Aedes, such as A. aegypti, and arboreal mosquitoes such as A. africanus, A. apicoargenteus, A. furcifer, A. hensilli, A. luteocephalus, and A. vitattus. So it has no total pandemic potential. It can be only in some geographic areas.

But the main issue that it potentially dangerous to pregnant women. Data suggests that newborn babies of mothers who had a Zika virus infection during the first trimester of pregnancy are at an increased risk of microcephaly.

Let say, that it is like "Rubella". So we need to pay attention to this virus. It becomes well known and popular because of new  diagnostic methods. So, it is not a real pandemia, it is our new level of knowledges.

There's been over 4000 cases of babies born with microcephaly in Brazil since October. That had never happened before and has nothing to do with diagnostic methods. Zika virus is getting all 'dramatic' news because it's clearly spreading in Americas and if nothing is done more ill babies will be born.

So I do think that it's a serious situation and some major research is necessary to figure out the pathogenesis of the virus and to develop a vaccine.  

It depends on how you define a serious pandemic potential. As Demina pointed out, it depends on mosquitos of the genus Aedi. The direct spread from human to human is a very rare event and does not pose a serious risk. Therefore, in areas, where Aedis mosquitos are present, Zika imposes an epidemic potential, especially dangerous for pregnant women (or more precisely their unborn babies). Considering, that it was likely quite recently introduced from Africa to South and Central America, it fulfills the criteria for a pandemic.

So to make a long story short: Yes, it has a serious pandemic potential, especially endangering unborn children.

It always estonishes me to see some outbreaks of  epidemies and potential pandemies, like SARS, some animal flues, or now Zika virus, but so far, none of them could kill the whole human population, not even the flue in Europe about 100 years ago. I have to admit I never understand HOW even the every-year's flu can stop, there may be a change of seasons, but summer in Europe means winter in Australia... Although the media currently focus on the terrible disease by Zika virus in newborns, it may not be clear what the perhaps rare effects on adults could be in the long range - and with many different genetic backgrounds.

I am not sure if I observed some of the first Aedi mosquitos in my region in Germany a few years ago (in a warm wine country with currently almond trees flowering since decemper, i.e. a few months earlier than natural), but liked the beauty of the insects.

So we will see how far the mosquitos and their virus can spread before anti-mosquito actions, and other preventions of disease may work. It may appear safe to avoid warm countries with such mosquitos.

As far as I know, some flaviviruses have already been isolated from mosquitos in Germany. Furthermore, with the increasing temperatures the Aedis mosquitos seem to spread further north. So, I would not feel too safe in central Europe or northern America.

For the anti-mosquito actions, I would not bet on them, if no new and overwhelmingly effective measures are developed. Although they help to contain the mosquito pest, they can not extinguish it. And the malaria epidemic quite sadly shows us where we stand at managing mosquito vector-borne diseases.

In Brazil, case reports of microcephaly are up from just over 400 in 2014 (417 I think) to over 3,500 in 2015. 

Rates of microcephaly are climbing dramatically. The latest figures are here: http://oglobo.globo.com/sociedade/saude/em-uma-semana-casos-de-microcefalia-no-rio-aumentam-194-18512507

Non-lusophones can run the page through Google translate. 

Note that the cases of zika are not the only think climbing. The same mosquito also carries dengue, and dengue cases are also rising rapidly. Dengue can lead to dengue haemorrhagic fever, which is potentially fatal. 

So with the current accelerating climate change, we can expect both zika and dengue to reach new populations that have no immunity. And, of course, with high levels of tourism to poor countries with warm climates, there is the obvious danger to people from rich countries with cool climates. 

Nonetheless, the victims will be concentrated in poor countries that lack the infrastructure and resources to contain the epidemic. Just like ebola. 

http://oglobo.globo.com/sociedade/saude/em-uma-semana-casos-de-microcefalia-no-rio-aumentam-194-18512507

Dear colleagues, thank you very much for your informative answers!

@Demina A.V., there is a medical joke: "The cause of the osteochondrosis epidemic is the invention of tomography" :)

Actually, by the improved diagnostics for infectious diseases we can explore the new infectious agents and new properties of the known agents. Zika virus was first isolated in 1947 and was known as "not dangerous". 

@Anna Albecka, you have a very nice position - you are humanist and are ready to save the world. It is beautiful! :)

I am agree with you about the pathogenesis, it is necessary to study this mechanism. It is very strange teratogen. The mechanism of specific influence of the virus to a foetus must be very complex.

I'm not sure about vaccine. The developing and examination of vaccine is a very long process and is not evident that it will be successful. For example, we still do not have any effective Dengue vaccine. I think the elimination of the mosquitos is more effective way and it is possible to start it immediately. There is a good example in history - the malaria elimination.  

@Michael Storcksdieck genannt Bonsmann, it is very good question "what is a serious pandemic potential?". I think it is a serious threat on a world scale - death or disability for millions people in several continents. I am not sure about Zika virus in this context - it is awful disease, but it is not looking too dangerous on a world scale.

@Robert H. Eibl, you have touched the very important area. The human population could not be eliminated by any infectious agent - the most important protection is the genetic variety. But it is self-evident, that any infection can kill the millions or even billions people. The tropical diseases can migrate to untypical regions by transport or by birds. For example, last years my colleagues in Siberia found West Nile virus in some ticks every summer.

In my opinion, it is necessary to check the messages from media. The sensations "New virus! We all will die!" are very attractive for some journalists.    

@Ronán Michael Conroy, the position of WHO is very careful:

During large outbreaks in French Polynesia and Brazil in 2013 and 2015 respectively, national health authorities reported potential neurological and auto-immune complications of Zika virus disease. Recently in Brazil, local health authorities have observed an increase in Zika virus infections in the general public as well as an increase in babies born with microcephaly in northeast Brazil. Agencies investigating the Zika outbreaks are finding an increasing body of evidence about the link between Zika virus and microcephaly. However, more investigation is needed before we understand the relationship between microcephaly in babies and the Zika virus. Other potential causes are also being investigated. 

http://www.who.int/mediacentre/factsheets/zika/en/

Today there are not enough information for understanding of the problem. It is necessary to do a monitoring of the population for Zika antibodies for the estimation of the  prevalence of this virus.

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Dear colleagues, what do you think about the mechanism of Zika virus teratogenicity?

Best regards,

Denis

En Guatemala C.A  se han confirmado 68 nuevos casos, manteniendo una vigilancia epidemiologia activa,  se tienen al momento mas de 200 sospechosos, los lugares mas afectados son Zacapa, Jutiapa y Escuintla.

Dear Dr. Sergio Vinicio Pérez, thank you very much for the answer!

What happened in Guatemala? Are these cases of birth with microcephaly or just fever for adults? 

So the WHO seems to take this virus very serious - currently warning as a world wide thread. I think only regions where the virus is ther for decades may not suffer from the current risks for newborns (probably since everone has antibodies from early on), but now with 1,5 million infected pregnant women in south america, this might be a problem. But I am wondering, if, for mid-European countries the other, but similar mosquitos (same genus Aedes) may soon spread the virus as well. I am sure that I have seen such mosquitos during the last several years in the vine country I currently live, but still it is not exactly the same species of mosquito.

Yes. The main problem is how the virus affect pregnant woman. It's not clear, but probably most cases of microcephaly are due to ZIKA virus and most cases of infection in preganancy are completely asymptomatic.

I dont think so, infact the vector for ZIKA virus cannot tolerate every enviromental conditions.

By difficulties in controlling its transmitter, which has great ease of spreading.

I sugest the next información of WHO (February 01, 2016) http://www.who.int/mediacentre/news/statements/2016/1st-emergency-committee-zika/en/

zika has the potential to spin out of control if no active surveillance is instituted. The danger is that clinical signs are not very specific and this poses a challenge. The experience of Brazil is very worrying considering that the virus is been around and never caused a big public health problem. I know no major or big numbers of microcephary in Uganda for all this time. The population around Entebbe is not littered with these children. We may want to ask the simple question: is this the same virus with the same virulence ? We should be concerned about mutation . 

The interesting related question:

https://www.researchgate.net/post/Has_it_been_scientifically_proven_that_Zika_virus_is_the_cause_of_microcephaly

Another link

https://www.researchgate.net/post/What_is_best_web_site_for_computational_resources_on_Zika_Virus

@Gajendra Pal Singh Raghava

you can get up to date information on what is happening as well as areas for research and updates on the following website

https://zikainfection.tghn.org/