On 1 February 2016, the World Health organization (WHO) declared that the recent cluster of microcephaly cases and other neurological disorders reported in the America’s, where an outbreak with Zika virus is ongoing, constitutes a Public Health Emergency of International Concern (PHEIC). The CDC (Centers for Disease Control and Prevention, Atlanta, USA) activated its Emergency Operations Center and elevated it to a Level 1, the highest level. Zika virus is a mosquito-borne virus (genus Flavivirus, family Flaviviridae) related to yellow fever, dengue, West Nile, Japanese encephalitis and tick-borne encephalitis viruses, first isolated in 1947 from Rhesus macaques living in the eponymous forest in Uganda. There is currently no vaccine for preventing Zika virus infection and no specific medication for treating the disease. As the symptoms are non-specific (mild symptoms including tiredness, fever, headaches, muscular and joint pain in the limbs, skin rash, conjunctivitis, pain behind the eyes, digestive problems, or swelling of the hands or feet) and the Zika virus is found in the same regions as the dengue and chikungunya viruses, accurate diagnosis are made difficult. Furthermore, infection is unapparent in most of the cases. Before 2015, Zika virus outbreaks occurred in areas of Africa, Southeast Asia, and the Pacific Islands. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil. Zika virus has since spread explosively. Between 19 November 2015 and 3 February 2016, 26 countries reported autochthonous cases of Zika virus infection, mainly in South America (the most affected country is Brazil with more than 1.5 million cases detected) but also in Asia (Thailand). Considering travelers imported cases, 34 countries in total are affected (see the WHO Zika situation report of February 12, 2016). Besides globalization and an expected huge number of cases including an increase of exported cases, major concern is raising from the possible association with Guillain-Barré syndrome, microcephaly and other neurological manifestations in new-borns in the current epidemic region. In Brazil especially, more than 4,700 cases of suspected microcephaly have been recorded from mid-2015 to end January 2016. This association still needs to be unequivocally established.
You can further read the editorial from Dr. David Heymann and colleagues published in The Lancet on February 10, 2016 after the declaration of WHO: Zika virus and microcephaly: why is this situation a PHEIC?
You can also visit Institut Pasteur website and check the Institut Pasteur International Network teams working on Zika virus.
Finally, also check www.zikainfection.org, the collaborative website set up by ISARIC (International Severe Acute Respiratory and emerging Infection Consortium) listing currently ongoing or planned research activities on Zika virus and giving access to Case Report Forms for standardised data capture.