Superinfection exclusion studies using West Nile virus and Culex flavivirus strains from Argentina.

In Argentina, many Flavivirus were recognised including West Nile virus (WNV). During 2009 several strains of Culex Flavivirus (CxFV), an insect-specific flavivirus, were isolated in the same region where circulation of WNV was detected. Hence, the objective of this study was to analyse the effect of co-infection in vitro assays using CxFV and WNV Argentinean strains in order to evaluate if CxFV could affect WNV replication. Our results showed that WNV replication was suppressed when multiplicity of infection (MOI) for CxFV was 10 or 100 times higher than WNV. Nevertheless, in vivo assays are necessary in order to evaluate the superinfection exclusion potential.

Superinfection exclusion studies using West Nile virus and Culex flavivirus strains from Argentina

In Argentina, many Flavivirus were recognised including West Nile virus (WNV). During 2009 several strains of Culex Flavivirus (CxFV), an insect-specific flavivirus, were isolated in the same region where circulation of WNV was detected. Hence, the objective of this study was to analyse the effect of co-infection in vitro assays using CxFV and WNV Argentinean strains in order to evaluate if CxFV could affect WNV replication. Our results showed that WNV replication was suppressed when multiplicity of infection (MOI) for CxFV was 10 or 100 times higher than WNV. Nevertheless, in vivo assays are necessary in order to evaluate the superinfection exclusion potential.

Hantaviruses and cardiopulmonary syndrome in South America.

Hantavirus (Bunyaviridae) cardiopulmonary syndrome (HCPS) is an emerging health problem in South America due to urban growth and to the expansion of agriculture and cattle-raising areas into ecosystems containing most of the species of Sigmodontinae rodents that act as hantavirus reservoirs. About 4000 HCPS cases have been reported in South America up to 2013, associated with the following hantaviruses: Andes, Anajatuba, Araraquara (ARQV), Paranoá, Bermejo, Castelo dos Sonhos, Juquitiba, Araucária, Laguna Negra, Lechiguanas, Maripa, Oran, Rio Mamore and Tunari. The transmission of hantavirus to man occurs by contact with or through aerosols of excreta and secretions of infected rodents. Person-to-person transmission of hantavirus has also been reported in Argentina and Chile. HCPS courses with a capillary leaking syndrome produced by the hantavirus infecting lung endothelial cells and mostly with a severe inflammatory process associated with a cytokine storm. HCPS starts as a dengue-like acute febrile illness but after about 3 days progresses to respiratory failure and cardiogenic shock, leading to a high fatality rate that reaches 50% for patients infected with ARQV.

Isolation of yellow fever virus from mosquitoes in Misiones province, Argentina.

Yellow fever (YF) is a viral hemorrhagic fever endemic to tropical regions of South America and Africa. From 2007 to 2009 an important epidemic/epizootic of YF was detected in different populations of howler monkeys (Alouatta species) in Misiones, a northeastern Argentinian province. Yellow fever virus (YFV) infection was researched and documented by laboratory tests in humans and in dead Alouatta carayá. The objective of that research was to investigate the circulation of YFV in mosquitoes, which could be implicated in the sylvatic transmission of YF in Argentina. The above-mentioned mosquitoes were captured in the same geographical region where the epizootic took place. A YFV strain was isolated in cell culture from pools of Sabethes albiprivus. This study is not only the first isolation of YFV from mosquitoes in Argentina, but it is also the first YFV isolation reported in the species Sabethes albiprivus, suggesting that this species might be playing a key role in sylvatic YF in Argentina.