Thanks to Greg Folkers for sending the link to this report in The Lancet: Zika virus: following the path of dengue and chikungunya?
On May 7, 2015, the Pan American Health Organization issued an alert about potential Zika virus (ZIKV) transmission in northeast Brazil.1 This has now been confirmed with wide spread of the disease, underscoring the potential for ZIKV to spread globally, similar to dengue (DENV) and chikungunya (CHIKV) viruses.
ZIKV is an emerging arthropod-borne virus (arbovirus) that was first isolated from a Rhesus monkey in Uganda, in 1947. This arbovirus is related to DENV and they have similar epidemiology and transmission cycle in urban environments. Until recently, only sporadic human ZIKV infections were reported. In 2007, ZIKV emerged outside of Asia and Africa for the first time and caused an epidemic on Yap Island in the Federated States of Micronesia,2 which was followed by a large epidemic in French Polynesia in 2013–14.3 Subsequently, ZIKV spread to several countries in Oceania (figure).4
The clinical presentation of ZIKV infection is not specific (mild fever, rash, arthralgia, and conjunctivitis) and can be confused with other diseases, especially dengue and chikungunya. Prior to the French Polynesian epidemic, during which severe neurological complications (Guillain-Barre syndrome) were confirmed, ZIKV was believed to cause only mild diseases.
The history of ZIKV resembles that of CHIKV, an alphavirus.5 First described in Africa in 1952, CHIKV emerged in Asia and caused major epidemics in India and southeast Asia between the 1950s and 1980s, before it disappeared epidemiologically. In 2004, CHIKV re-emerged in east Africa and spread to Asia again before spreading worldwide. CHIKV, similar to DENV, now circulates in all inhabited continents, evolving to a global public health problem in the past decade.
The adaptation of ZIKV to an urban or peri-urban cycle, involving Aedes aegypti and other mosquitoes of the Stegomyia subgenus as vectors and humans as amplification hosts, should be of great concern to public health officials. With more than half of the world's human population living in areas infested with these mosquitoes, the potential for major urban epidemics of ZIKV, DENV, CHIKV, yellow fever, epidemic polyarthritis, and other as yet unknown mosquito-borne viruses that might emerge, is overwhelming, and underscores the desperate need to develop more effective mosquito control as well as vaccines and drugs.
The future of ZIKV is unpredictable, but the worldwide spread of DENV and CHIKV—closely tied to the trends of urbanisation and globalisation, suggests that ZIKV has the potential to follow in their path.