Bluetongue is an insect-transmitted viral disease of ruminant species, which represents a major barrier to the international trade of animals and their products. Bluetongue virus (BTV) has a genome composed of ten linear segments of dsRNA, which code for at least ten different viral proteins. In South America, serological evidence for the presence of BTV has been found in Peru, Argentina, Brazil, Ecuador and Chile. Brazil and Argentina are the only South American countries where BTV has been isolated. In Brazil, only one BTV isolate, serotype 12, has been reported, whereas in Argentina five BTV serotype 4 isolates have been obtained from cattle without clinical signs. Three of these five isolates were isolated during 1999–2001, whereas two of them were obtained as part of the present work. This study describes sequence comparisons and phylogenetic analyses of segment (Seg)-2, Seg-3, Seg-6, Seg-7 and Seg-10 of the first Argentinian field isolates of BTV. The analysis of Seg-2 and Seg-6 resulted in a single cluster of Argentinian sequences into the serotype 4 clade. In addition, the Argentinian sequences grouped within the nucleotype A clade, along with reference strains. The analysis of Seg-3, Seg-7 and Seg-10 showed that the Argentinian isolates grouped into the western topotype, indicating that the circulating virus had an African/European origin. Phylogenetic analysis revealed that the Argentinian sequences present a South American genetic identity, suggesting an independent lineage evolution.

The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies.

Western equine encephalitis virus (WEEV) is a mosquito-borne arbovirus (genus Alphavirus, family Togaviridae) that has re-emerged in South America in late 2023, causing severe disease in both horses and humans after a nearly 40-year intermission period. We here describe the virological, serological, pathological, and molecular features of WEEV infection in horses during the 2023–2024 outbreak in Argentina. WEEV-infected horses developed neurological signs with mild to severe encephalitis associated with minimal to abundant WEEV-infected cells, as demonstrated by WEEV-specific in situ hybridization. The distribution of viral RNA was multifocal, with predominance within neuronal bodies, neuronal processes, and glial cells in the medulla oblongata and thalamic regions. Phylogenetic analysis of partial nsP4 sequences from three viral isolates obtained from three different provinces of Argentina support grouping with other temporally current WEEV strains from Uruguay and Brazil under a recently proposed novel lineage.