The view expressed in this letter is that the answer to question posed by the editorial is “Yes, we should worry, but about what?” Dr Wiwanitkit's main concern is rapid and accurate diagnosis. First, because many asymptomatic cases may go undetected, leading to further spread of the disease, and second because the long-term complications may be a problem.

The answer to the editorial question was implicitly yes. Three main concerns were established1: (1) Zika disease control (including case detection) in countries with local transmission; (2) detection of cases in Spain; and (3) vector monitoring and control in Spain. I do not think that undiagnosed asymptomatic cases are a main concern in our environment. If we are able to diagnose symptomatic cases, we can determine the extent of the disease, based on our knowledge about the proportion of subclinical cases. Suboptimal diagnosis is part of the more general health infrastructure problem affecting countries with a higher prevalence of Zika. Finally, it is true that we do not know whether long-term complications can affect patients with subclinical infection. As many aspects of the pathogenesis remain unclear and an association with neurological sequelae has been demonstrated, epidemiological studies that address these problems are clearly needed.2 This does not, however, change our three main concerns.