The West Nile virus epidemic-occupational insight

We read with interest the World Report by Talha Burki (Sep 22, 2018, p 1000)1 about the sudden rise in the number of cases of West Nile virus across Europe in 2018. We have concerns, however, that the current epidemiological surveillance systems in the report do not provide a complete overview of the situation. In our daily work as occupational doctors, outdoor workers often present with flu-like symptoms outside the flu season. In most cases of West Nile virus infection, the evolution of these flu-like symptoms is usually selflimiting in previously healthy workers, leading to a quick return to work without a precise diagnosis being made. Sentinel cases of West Nile virus infection (ie, patients who develop a serious, sometimes fatal, neurological illness, often associated with older age groups, pregnancy, immunodeficiency or comorbidities2) are infrequently reported in the workplace and account for less than 1% of cases.3 Consequently, we hypothesise that many individuals with West Nile virus infection present to occupational doctors a long time before the onset of complications or fatality. Laboratory testing of blood samples for West Nile virus only occurs in regions where sentinel cases have already been identified. This policy might not correspond to suitable allocation of resources and might lead to a partial view of the issue from an epidemiological perspective. This situation could be improved with data obtained from regular health surveillance in the workplace.