Endemic tickborne infectious diseases in Louisiana and the Gulf South.

Most emerging infectious diseases today, such as West Nile virus and sudden acute respiratory distress syndrome (SARS), arise from zoonotic reservoirs and many are transmitted by arthropod vectors. Ticks are among the most competent and versatile arthropod vectors of infectious diseases because ticks of all ages and both sexes remain infectious for generations without having to reacquire infections from reservoir hosts. Today, ticks transmit the most common arthropod-borne infectious disease in the United States (US), Lyme disease (LD); and the most lethal arthropod-borne infectious disease in the US, Rocky Mountain spotted fever (RMSF). Both LD and RMSF are endemic in Louisiana and the Gulf South. Ticks have also become frequent vectors of emerging zoonotic diseases in the Gulf South, including southern tick-associated rash illness (STARI), transmitted by the lone star tick, and Maculatum disease, transmitted by the Gulf Coast tick. Recent environmental changes and human lifestyle choices now place humans and ticks together outdoors in the Gulf South for longer periods in welcoming ecosystems for breeding, blood-feeding, and infectious disease transmission. An increasing incidence of emerging and re-emerging, endemic infectious diseases transmitted by existing and unanticipated tick vectors may be expected.