Arbovirus disease cases vary from year to year and some even cycle over a period of three to four years. Many things influence the number of cases, such as the number of mosquitoes that spread the disease and the weather that affects their breeding.
Some arboviruses actively cause outbreaks within the United States (eg, West Nile virus). Others rarely occur within the US (found mainly in other countries) and infection comes primarily from people who travel to those areas (eg, dengue virus). Still others may be transitioning to actively causing disease within the US, as the necessary vector for a particular arbovirus emerges in the US through possible mechanisms, such as global trade (eg, Zika virus).
Most arboviruses do not yet have vaccines, so prevention depends on people preventing mosquito bites and eliminating breeding sites. Clinicians must have a high index of suspicion to diagnose and report them. All of the mosquito-borne viral infections detected in the US must be reported to the Centers for Disease Control and Prevention (CDC).