Health 1 February 2016 The Zika virus continues to spread while creating an international health crisis Eyes are on the World Health Organisation to declare the outbreak of the virus an emergency. Mario Tama/Getty Sign UpGet the New Statesman's Morning Call email. Sign-up The Zika virus, linked to birth defects in newborn babies, is continuing to spread across the western hemisphere. The virus is carried by the Aedes aegypti mosquitoes, a species that is growing due to global warming. As well as neurological disorders, the most significant birth defect the virus is known to cause is microcephaly. This results in babies born with smaller craniums and brains, which can lead to slower development and overall lower mental progression compared with healthier babies. Microcephaly is usually caused by exposure to toxic substances during pregnancy, diseases such as herpes or genetic abnormalities. The UN's World Health Organisation (WHO) is holding a summit in Geneva to decide whether or not to declare the rapid outbreak of the virus an international emergency. This would kickstart a campaign to raise further awareness of the disease, provide guidance and speed up attempts to find a vaccine. The group will want to avoid a repeat of the slow reacton towards the Ebola outbreak in parts of Africa in 2013. Regardless of WHO's announcement, they have already forecast an estimated 4m people could become infected with the virus by the end of the year. This is significant because approximately 80 per cent of those infected with the virus show no symptoms, while those who suffer from the disease display flu-like fevers, muscular pain and rashes. The forecast of 4m potential infections is staggering given the huge increase in microcephaly cases in the last six months in South America. Many doctors have been urging extreme caution, such as the use of bed nets, long clothing and avoiding extended periods in the outdoors. However, some have been advising against pregnancy altogether, with the Colombian government stating pregnancies should be delayed by up to eight months, and El Salvador asking citizens to avoid pregnancies until at least 2018. What's tragic about this subject is not just the thousands of children being born with this defect, but the repercussions of the advice and what it will entail for the future, both in the short and long term. Later this year, thousands will be travelling across the globe to Brazil for the summer Olympics, and this major public health crisis is the last thing organisers want to deal with given the difficulty in arranging such a large, international event. Also, some countries are already suffering from various population crises. For example, the falling birth rate and strict immigration rules of Japan are leading to dire warnings of a diminishing population. And while China's (now extinct) one-child policy was imposed in order to control a surging population, it created an unforseen problem of a typical working couple needing to take care both of a child and four parents. A temporary but significant drop in population growth and birth rates could have similarly difficult outcomes in South America. It is important to keep in mind the roles of family planning resources, national health care systems and abortion services in South America when looking at the potential long-term effects of the Zika virus. For example, it is completely illegal to have an abortion in El Salvador, and countries like Brazil and neighbouring Argentina only permit the operation if the mother's life is at risk, or if the pregnancy is the result of rape. The work of NGOs is also crucial. The International Planned Parenthood Federation (IPFF) provides millions of condoms across the world, gives sexual health advice and also voluntary surgical contraception. These services will become even more precious and pressured in those countries while scientists try to produce a vaccine against the virus. All of these moving parts show just how complicated it is to organise a concerted public health campaign and the potential ramifications the Zika virus poses. It's now for national governments, NGOs and the scientific community to band together to stop the threat posed by the disease. › Sky’s gazumping is killing popular drama imports – TV with no viewers isn’t TV at all Emad Ahmed writes about science and gaming. He tweets @ThisIsEmad. Subscribe To stay on top of global affairs and enjoy even more international coverage subscribe for just £1 per month!