Unprecedented plant species loss after a decade in fragmented subtropical Chaco Serrano forests.

Current biodiversity loss is mostly caused by anthropogenic habitat loss and fragmentation, climate change, and resource exploitation. Measuring the balance of species loss and gain in remaining fragmented landscapes throughout time entails a central research challenge. We resurveyed in 2013 plant species richness in the same plots of a previous sampling conducted in 2003 across 18 forest fragments of different sizes of the Chaco Serrano forest in Argentina.

Neuronal Degeneration in Mice Induced by an Epidemic Strain of Saint Louis Encephalitis Virus Isolated in Argentina.

Saint Louis encephalitis virus (SLEV) is a neglected flavivirus that causes severe neurological disorders. The epidemic strain of SLEV, CbaAr-4005, isolated during an outbreak in Córdoba city (Argentina), causes meningitis and encephalitis associated with neurological symptoms in a murine experimental model. Here, we identified the affected brain areas and the damage triggered by this neurotropic arbovirus.

Alphaviruses: Serological Evidence of Human Infection in Paraguay (2012-2013).

Introduction: Alphaviruses can produce febrile illness and encephalitis in dead-end hosts such as horses and humans. Within this genus, the Venezuelan Equine Encephalitis virus (VEEV) complex includes pathogenic epizootic subtypes and enzootic subtypes that are not pathogenic in horses (except subtype IE, Mexican strains), although they can cause febrile symptoms in humans. The Rio Negro virus (RNV-VEEV subtype VI) circulates in Argentina, where it was associated with undifferentiated febrile illness.

Pixuna virus modifies host cell cytoskeleton to secure infection.

Pixuna virus (PIXV) is an enzootic member of the Venezuelan Equine Encephalitis Virus complex and belongs to the New World cluster of alphaviruses. Herein we explore the role of the cellular cytoskeleton during PIXV replication. We first identified that PIXV undergoes an eclipse phase consisting of 4 h followed by 20 h of an exponential phase in Vero cells.

Tissue tropism of Saint Louis encephalitis virus: Histopathology triggered by epidemic and non-epidemic strains isolated in Argentina.

Saint Louis encephalitis virus (SLEV) reemerged in South America, and caused encephalitis outbreaks at the beginning of the 21st century. To enhance our knowledge about SLEV virulence, we performed comparative pathogenesis studies in Swiss albino mice inoculated with two different variants, the epidemic strain CbaAr-4005 and the non-epidemic strain CorAn-9275. Only the infection of mice with SLEV strain CbaAr-4005 resulted in high viremia, invasion of peripheral tissues including the lungs, kidney, and spleen, and viral neuroinvasion.

Virulence variation among epidemic and non-epidemic strains of Saint Louis encephalitis virus circulating in Argentina.

Saint Louis encephalitis virus caused an outbreak of febrile illness and encephalitis cases in Córdoba, Argentina, in 2005. During this outbreak, the strain CbaAr-4005 was isolated from Culex quinquefasciatus mosquitoes. We hypothesised that this epidemic variant would be more virulent in a mouse model than two other non-epidemic strains (78V-6507 and CorAn-9275) isolated under different epidemiological conditions.

Introduction of different lineages of Aedes aegypti in Argentina.

Based on sequence analysis of the mitochondrial gene ND4, we determined the presence in Argentina of 3 haplotypes representing different Aedes (Stegomyia) aegypti lineages previously identified in other countries of the Americas, Africa, and Asia. Haplotype 17, the most frequent in Argentina, was previously detected in Brazil. Haplotype 7, restricted in our study to the northwest of Argentina and Bolivia, was formerly found in low frequency in the USA, Brazil, Mexico, and Senegal.

Silent circulation of St. Louis encephalitis virus prior to an encephalitis outbreak in Cordoba, Argentina (2005).

St. Louis encephalitis virus is a complex zoonoses. In 2005, 47 laboratory-confirmed and probable clinical cases of SLEV infection were reported in Córdoba, Argentina.

Phylogeography of Aedes aegypti in Argentina: long-distance colonization and rapid restoration of fragmented relicts after a continental control campaign.

Aedes (Stegomyia) aegypti, the main vector of Dengue and Yellow Fever viruses, is present in all the northern and central provinces of Argentina. During 2009, a Dengue outbreak spread broadly throughout the country, causing 27,752 infections in 13 provinces. In Argentina, little is known about the demographic history of this vector, which suffered a drastic decrease in abundance and distribution during a major control campaign performed in the Americas between 1950 and 1960.

Structural organization of the mitochondrial DNA control region in Aedes aegypti.

The complete A+T - rich region of Aedes aegypti mitochondrial DNA has been cloned and sequenced. In Argentinean populations of the species, a polymorphism in the length of the amplified fragment was observed. Nucleotide sequence comparison of the shortest and longest A+T - rich amplified fragments detected revealed the presence of 2 types of tandemly repeated blocks.