ABSTRACT
BACKGROUND Dengue virus (DENV) has circulated in Brazil for over 30 years. During this time, one serotype has cyclically replaced the other, until recently, when all four distinct serotypes began to circulate together. Persistent circulation of DENV for long time periods makes sequential infections throughout a person's life possible. After primary DENV infection, life-long immunity is developed for the infecting serotype. Since DENV and Zika virus (ZIKV) are antigenically similar, the possibility of cross-reactions has attracted attention and has been demonstrated in vitro. OBJECTIVE The aim of this study was to investigate whether immune-sera from DENV and ZIKV infected patients would cross-react in vitro with other Flaviviridae family members. METHODS Cross-reaction of the studied samples with yellow fever virus (YFV), West Nile virus (WNV), Rocio virus (ROCV), Saint Louis virus (SLEV) and Ilheus virus (ILHV) has been investigated by plaque reduction neutralisation test (PRNT) and the antibody-dependent enhancement (ADE) by flow-cytometry. FINDINGS Antibodies against ZIKV and DENV virus cross-reacted with other flaviviruses either neutralising or enhancing the infection. Thus, viral entrance into FcRFcɣRII-expressing cells were influenced by the cross-reactive antibodies. ZIKV or DENV immune sera enhanced cellular infection by WNV, ILHV, ROCV and SLEV. Finally, DENV immune sera presented higher neutralising activity for YFV and SLEV. While ZIKV immune sera neutralised WNV, ILHV and ROCV with high frequencies of positivity. MAIN CONCLUSIONS The co-circulation of those viruses in the same area represents a risk for the development of severe infections if they spread throughout the country. Successive flavivirus infections may have an impact on disease pathogenesis, as well as on the development of safe vaccine strategies.
Subject(s)
Animals , Zika Virus Infection/diagnosis , Zika Virus Infection/prevention & control , Flavivirus , Zika Virus , CulicidaeABSTRACT
Ticks infesting amphibians and reptiles in the State of Pernambuco are reviewed, based on the current literature and new collections recently carried out by the authors. To date, three tick species have been found on amphibians and reptiles in Pernambuco. Amblyomma fuscum appears to be exclusively associated with Boa constrictor, its type host. Amblyomma rotundatum has a relatively low host-specificity, being found on toads, snakes, and iguana. Amblyomma dissimile has been found on a lizard and also small mammals (i.e., rodents and marsupials). New tick-host associations and locality records are given.
Os carrapatos encontrados infestando anfíbios e répteis no Estado de Pernambuco são revisados com base na literatura atual e em novas coletas realizadas recentemente pelos autores. Até o momento, três espécies de carrapatos foram encontradas sobre anfíbios e répteis em Pernambuco. Amblyomma fuscum parece estar exclusivamente associado à Boa constrictor, seu hospedeiro-tipo. Amblyomma rotundatum tem uma especificidade parasitária relativamente baixa, sendo encontrado em sapos, serpentes e iguana. Amblyomma dissimile já foi encontrado sobre um lagarto e também sobre pequenos mamíferos (isto é, roedores e marsupiais). Novas associações carrapato-hospedeiro e novos registros de localidades são apresentados.