Vector competence of Argentinean Aedes aegypti population for different strains of Zika virus.

BONICA MELISA BERENICE; GOENAGA SILVINA; MARTIN MARIA LAURA; FEROCI MARIEL; LUPPO VICTORIA,; FABBRI CINTIA; MORALES MARIA ALEJANDRA; MICIELI MARIA VICTORIA,; ENRIADELIA; LEVIS SILVANA

Ciudad Autónoma de Buenos Aires

Congreso; 18 th International Congress on infectious diseases. XVIII Congreso SADI.; 2018

International Society of infectious Disease

PURPOSESince the emergence of Zika virus (ZIKV; Flaviviridae; Flavivirus) in Brazil in 2015, the virus has spread quickly in 48 countries along the American continent resulting in millions of infections. Although these infections usually cause a mild illness, the virus is also associated with serious congenital disease and other neurological disorders as Guillain-Barré syndrome, which makes ZIKV an important target of study.Moreover, a few cases of sexual transmission were reported suggesting an alternative route of transmission.In Argentina the first outbreakwas detected in San Miguel de Tucumán in 2016, followed by others during 2017 in Salta, Formosa and Chaco provinces, causing many human infections. However, thereis no report of ZIKV isolation in mosquito, remaining the question about which mosquito species are involved in vector transmission in Argentina.The aim of this study is to evaluate the vector competence of local populations of Aedes aegyption transmitting both, an imported ZIKV strain and an autochthon strain, in order to contribute to understand the dynamics of Zika in Argentina.METHODS AND MATERIALSIn order to assess vector competence, an autochthon population of Aedes aegyptifrom La Plata, Buenos Aires province,was artificially fed with two ZIKV strains, oneof them isolated from an autochthon case and the other from an imported case from Venezuela (Fig. 1).Bodies, legs, and saliva were harvested from each mosquito in order to evaluate infection, dissemination and transmission rates for ZIKV.We evaluate infection, dissemination and transmission rates for both strains at 7, 9, 11 and 14 days post-inoculation (DPI). We also estimated the extrinsic incubation period (EIP) and ZIKV titers were evaluated by plaque assay on Vero cells under agarose.RESULTSResults show that for the Venezuelan strain infection rates of the mosquito appear from the 7 DPI, dissemination rates manifest on 9 DPI, while transmission rates are very low (2.6%) and with very low titers (30 PFU/ml). For the Argentinean strain, both infection and dissemination rates appear from the 7 day post inoculation, and the transmission rate is 10%. The minimum EIP is 11 days after artificial infectionforArgentinean strain and 14 days for Venezuelan strain (Fig. 2).CONCLUSIONSThe different transmission pathways of this flavivirus point out a complex scenario in the epidemiology of Zika. In this study we demonstrated the capacity of Aedes aegypti mosquitoes from La Plata to infect and disseminate with both, an autochthon strain and an imported one. However, the low rates of transmission and the low titers forboth strains in saliva, show that mosquitoes from La Plata are not able to transmit Zika at least for the first 14 days post infection.Nevertheless, further experiments should be performed in order to evaluate the role of other Aedes aegyptipopulations to transmit Zika virus.