History of arthropod-borne virus infections in French Polynesia.

In French Polynesia, arthropod-borne diseases are major public health problems. From the mid-1940s, the four serotypes of dengue virus (DENV-1 to -4) have caused 15 epidemics of variable severity. In 2013, for the first time, a sustained co-circulation of two different DENV serotypes (DENV-1 and -3) was reported. The same year, Zika virus (ZIKV) caused the largest outbreak ever recorded at that time. Severe neurologic complications in adults, including Guillain-Barré syndrome and central nervous system malformations in newborns and foeteuses, such as microcephaly, were reported, and a causal link with ZIKV infection was established. In addition to mosquito-borne transmission, the potential for perinatal, sexual and blood-transfusion transmission of ZIKV was demonstrated. In 2014, chikungunya virus (CHIKV) caused an explosive outbreak. Series of Guillain-Barré syndrome temporally associated with the CHIKV epidemic were reported. Except for DENV, ZIKV and CHIKV, no other arboviruses have been detected so far, but serologic evidence suggested the past silent circulation of Ross River virus. From May 2015 DENV-1 has been the only arbovirus transmitted in French Polynesia, but the reemergence of DENV-2 is highly expected since the detection of two autochthonous cases of DENV-2 infection in June 2018.