Complete genomic sequences of Venezuelan equine encephalitis virus subtype IIID isolates from mosquitoes.

Venezuelan equine encephalitis virus (VEEV) is an important pathogen of medical and veterinary importance in the Americas. In this report, we present the complete genome sequences of five VEEV isolates obtained from pools of Culex (Melanoconion) gnomatos (4) or Culex (Melanoconion) pedroi (1) from Iquitos, Peru. Genetic and phylogenetic analyses showed that all five isolates grouped within the VEEV complex sister to VEEV IIIC and are members of subtype IIID. This is the first report of full-length genomic sequences of VEEV IIID.

Crimean-Congo Hemorrhagic Fever Virus, Mongolia, 2013-2014.

During 2013-2014, we collected 1,926 serum samples from humans and 4,583 ticks (Hyalomma asiaticum or Dermacentor nuttalli) in select regions of Mongolia to determine the risk for Crimean-Congo hemorrhagic fever virus (CCHFV) infection among humans in this country. Testing of human serum samples by ELISA demonstrated an overall CCHFV antibody prevalence of 1.4%; Bayankhongor Province had the highest prevalence, 2.63%. We pooled and analyzed tick specimens by real-time reverse transcription PCR; 1 CCHFV-positive H. asiaticum tick pool from Ömnögovi was identified. In phylogenetic analyses, the virus's partial small segment clustered with CCHFV isolates from Central Asia, and the complete medium segment grouped with CCHFV isolates from Africa, Asia, and the Middle East. This study confirms CCHFV endemicity in Mongolia and provides information on risk for CCHFV infection. Further research is needed to better define the risk for CCHFV disease to improve risk mitigation, diagnostics, and surveillance.

African and Asian Zika Virus Isolates Display Phenotypic Differences Both In Vitro and In Vivo.

Zika virus (ZIKV) is a mosquito-borne member of the genus Flavivirus that has emerged since 2007 to cause outbreaks in Africa, Asia, Oceania, and most recently, in the Americas. Here, we used an isolate history as well as genetic and phylogenetic analyses to characterize three low-passage isolates representing African (ArD 41525) and Asian (CPC-0740, SV0127-14) lineages to investigate the potential phenotypic differences in vitro and in vivo. The African isolate displayed a large plaque phenotype (∼3-4 mm) on Vero and HEK-293 cells, whereas the Asian isolates either exhibited a small plaque phenotype (∼1-2 mm) or did not produce any plaques. In multistep replication kinetics in nine different vertebrate and insect cell lines, the African isolate consistently displayed faster replication kinetics and yielded ∼10- to 10,000-fold higher peak virus titers (infectious or RNA copies) compared with the Asian isolates. Oral exposure of Aedes aegypti mosquitoes with the African isolate yielded higher infection and dissemination rates compared with the Asian isolates. Infection of Ifnar1-/- mice with the African isolate produced a uniformly fatal disease, whereas infection with the Asian isolates produced either a delay in time-to-death or a significantly lower mortality rate. Last, the African isolate was > 10,000-fold more virulent than the Asian isolates in an interferon type I antibody blockade mouse model. These data demonstrate substantial phenotypic differences between low-passage African and Asian isolates both in vitro and in vivo and warrant further investigation. They also highlight the need for basic characterization of ZIKV isolates, as the utilization of the uncharacterized isolates could have consequences for animal model and therapeutic/vaccine development.

Low potential for mechanical transmission of Ebola virus via house flies (Musca domestica).

BACKGROUND: Ebola virus (EBOV) infection results in high morbidity and mortality and is primarily transmitted in communities by contact with infectious bodily fluids. While clinical and experimental evidence indicates that EBOV is transmitted via mucosal exposure, the ability of non-biting muscid flies to mechanically transmit EBOV following exposure to the face had not been assessed. RESULTS: To investigate this transmission route, house flies (Musca domestica Linnaeus) were used to deliver an EBOV/blood mixture to the ocular/nasal/oral facial mucosa of four cynomolgus macaques (Macaca fascicularis Raffles). Following exposure, macaques were monitored for evidence of infection through the conclusion of the study, days 57 and 58. We found no evidence of systemic infection in any of the exposed macaques. CONCLUSIONS: The results of this study indicate that there is a low potential for the mechanical transmission of EBOV via house flies - the conditions in this study were not sufficient to initiate infection.