ABSTRACT
Zika virus (ZIKV) was first discovered in 1947 in Uganda but was not considered a public health threat until 2007 when it found to be the source of epidemic activity in Asia. Epidemic activity spread to Brazil in 2014 and continued to spread throughout the tropical and subtropical regions of the Americas. Despite ZIKV being zoonotic in origin, information about transmission, or even exposure of non-human vertebrates and mosquitoes to ZIKV in the Americas, is lacking. Accordingly, from February 2017 to March 2018, we sought evidence of sylvatic ZIKV transmission by sampling whole blood from approximately 2000 domestic and wild vertebrates of over 100 species in West-Central Brazil within the active human ZIKV transmission area. In addition, we collected over 24,300 mosquitoes of at least 17 genera and 62 species. We screened whole blood samples and mosquito pools for ZIKV RNA using pan-flavivirus primers in a real-time reverse-transcription polymerase chain reaction (RT-PCR) in a SYBR Green platform. Positives were confirmed using ZIKV-specific envelope gene real-time RT-PCR and nucleotide sequencing. Of the 2068 vertebrates tested, none were ZIKV positive. Of the 23,315 non-engorged mosquitoes consolidated into 1503 pools tested, 22 (1.5%) with full data available showed some degree of homology to insect-specific flaviviruses. To identify previous exposure to ZIKV, 1498 plasma samples representing 62 species of domestic and sylvatic vertebrates were tested for ZIKV-neutralizing antibodies by plaque reduction neutralization test (PRNT90). From these, 23 (1.5%) of seven species were seropositive for ZIKV and negative for dengue virus serotype 2, yellow fever virus, and West Nile virus, suggesting potential monotypic reaction for ZIKV. Results presented here suggest no active transmission of ZIKV in non-human vertebrate populations or in alternative vector candidates, but suggest that vertebrates around human populations have indeed been exposed to ZIKV in West-Central Brazil.
Subject(s)
Zika Virus Infection/epidemiology , Zika Virus Infection/virology , Zika Virus , Animals , Brazil/epidemiology , Culicidae , Geography, Medical , Humans , Mosquito Vectors , Neutralization Tests , Public Health Surveillance , Seroepidemiologic Studies , Zika Virus Infection/transmission , ZoonosesABSTRACT
The coccidian Caryospora bigenetica was first described in the snake Crotalus horridus (Viperidae) from United States of America. This study represents the first record of the occurrence of C. bigenetica in snakes in South America. Feces were sampled between November 2013 and May 2014 from 256 wild snakes maintained in scientific breeding facilities in the states of Mato Grosso do Sul (MS; n = 214) and Rio de Janeiro (RJ; n = 42), Brazil. Caryospora bigenetica was found in 14 (5.6%) snakes, all belonging to the family Viperidae. Ten Bothrops moojeni and two Crotalus durissus from MS were infected. The coccidian was also found in one C. durissus and in one Bothrops jararacussu from the state of RJ. The oocysts were spherical with a double wall, the exterior lightly mammillated, striations apparent in transverse view, 13.0 µm (12 14); polar granule fixed in the internal wall. Sporocysts oval or pyriform, 10.0 × 8.0 µm (9 11 × 8 9); Stieda body discoid; sub-Stieda body present; sporocyst residuum present, formed by a group of spheroid bodies between sporozoites. This study increases the number of viperid hosts of C. bigenetica and expands the geographical distribution to South America.
O coccídio Caryospora bigenetica foi descrito na serpente Crotalus horridus (Viperidae) nos Estados Unidos da América. Este estudo representa o primeiro registro da ocorrência de C. bigenetica em serpentes da América do Sul. Amostras de fezes foram obtidas, entre novembro de 2013 e maio de 2014, de 256 serpentes silvestres mantidas em um criatório científico nos Estados do Mato Grosso do Sul (MS; n = 214) e Rio de Janeiro (RJ; n = 42), Brasil. Caryospora bigenetica foi encontrada em 14 (5,6%) serpentes, todas pertencentes à família Viperidae. Dez Bothrops moojeni e duas Crotalus durissus de MS estavam infectadas. O coccídio também foi encontrado em uma C. durissus e uma Bothrops jararacussu do Estado do Rio de Janeiro. Os oocistos foram esféricos, com parede dupla, sendo a externa ligeiramente mamilonada, estriações aparentes transversalmente, 13.0 µm (12 14); grânulo polar junto à parede interna. Esporocisto oval ou piriforme, 10.0 × 8.0 µm (9 11 × 8 9); corpo de Stieda discóide; sub-Stieda presente; resíduo do esporocisto presente, formado por um grupo de corpos esféricos entre os esporozoítos. Este estudo aumenta o número de hospedeiros viperídeos de C. bigenetica e expande a distribuição geográfica para a América do Sul.
