Outbreak of Zika virus disease

1. Shrivastava SR, Shrivastava PS, Ramasamy J. 2015 outbreak of Zika virus disease declared as Public Health Emergency of International Concern: Justification, consequences, and the public health perspective. J Res Med Sci 2016 29;21:55. 2. Armstrong N, Hou W, Tang Q. Biological and historical overview of Zika virus. World J Virol 2017;6:1‐8. 3. Wiwanitkit S, Wiwanitkit V. Afebrile, asymptomatic and non‐thrombocytopenic Zika virus infection: Don’t miss it! Asian Pac J Trop Med 2016;9:513. 4. Jia P, Chen X, Chen J, Lu L, Liu Q, Tan X, et al. How does the dengue vector mosquito Aedes albopictus respond to global warming? Parasit Vectors 2017;10:140. 5. Wiwanitkit S, Wiwanitkit V. Sexually transmitted Zika virus infection: A new tropical disease. Asian Pac J Trop Dis 2016;6:757‐8. 6. Kim S, Rajadhan V. Seroprevalence of Zika virus in Cambodia: A preliminary report. Adv Lab Med Int 2016;6:37‐40. Sir, The publication on outbreak of Zika virus disease is very interesting.[1] Shrivastava et al. mentioned that “Zika virus disease has emerged as a major public health concern and is expected to increase further in magnitude owing to the lack of immunity among the population in the affected regions.”[1] There are some concerns on the situation. First, the extension of the disease is already worldwide.[2] Silent infection is possible in many countries, especially in tropical Asia. The high rate of asymptomatic infection can be seen and this might be underdiagnosed and recorded.[3] One might mention for tropical regions as an endemic area of mosquito‐borne Zika virus infection. However, the extension of mosquito habitat due to global warming should be concerned.[4] In addition, the disease can be transmitted by many routes including to sexual contact, and it becomes very hard to identify the exact endemic region of the disease at present.[5] Focusing on the immunity, as a new disease, there are limited data. In general, there should be no immunoreactive background among the local people in any setting. Focusing on clinical presentation, disease is not usually serious but mild and asymptomatic. Nevertheless, there is a report on high immunoreactive rate among local people in tropical country, where there is no previous history of disease existence; no previous reported case of congenital anomaly due to Zika virus infection.[6] This is an interesting finding for further study on protective immunity against Zika virus. All countries, not only the tropical countries or affected countries, should prepare for the coming of the disease.