ABSTRACT
In rabies diagnosis, it is essential to count on a rapid test to give a quick response. The combined sensitivity and robustness of the TaqMan RT-PCR assays (qRT-PCR) have made these methods a valuable alternative for rabies virus (RABV) detection. We conducted a study to compare the applicability of two widely used qRT-PCR assays targeting the nucleoprotein gene (LysGT1 assay) and leader sequences (LN34 qRT-PCR assay) of RABV genomes, in all variants circulating in Argentina. A total of 44 samples obtained from bats, dogs, cattle, and horses, that were previously tested for rabies by FAT and conventional RT-PCR, were used in the study. All variants were successfully detected by the pan-lyssavirus LN34 qRT-PCR assay. The LysGT1 assay failed to detect three bat-related variants. We further sequenced the region targeted by LysGT1 and demonstrated that the presence of three or more mismatches with respect to the primers and probe sequences precludes viral detection. We conclude that the LysGT1 assay is prone to yield variant-dependent false-negative test results, and in consequence, the LN34 assay would ensure more effective detection of RABV in Argentina.
Subject(s)
Genetic Variation , Rabies virus/genetics , Rabies/diagnosis , Rabies/virology , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Amino Acid Sequence , Animals , Argentina/epidemiology , Cattle , Chiroptera , Geography, Medical , Horses , Humans , Nucleoproteins/genetics , Phylogeny , Phylogeography , RNA, Viral , Rabies/epidemiology , Rabies virus/classification , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
Bats are among the most diverse, widespread, and abundant mammals. In Argentina, 67 species of bats have been recorded, belonging to 5 families and 29 genera. These high levels of biodiversity are likely to complicate identification at fieldwork, especially between closely related species, where external morphology-based approaches are the only immediate means for a priori species assignment. The use of molecular markers can enhance species identification, and acquires particular relevance in capture-release studies. In this study, we discuss the extent of the use of the mitochondrial cytochrome b gene for species identification, comparing external morphology identification with a molecular phylogenetic classification based on this marker, under the light of current bat systematics. We analyzed 33 samples collected in an eco-epidemiological survey in the province of Santa Fe (Argentina). We further sequenced 27 museum vouchers to test the accuracy of cytochrome b -based phylogenies in taxonomic identification of bats occurring in the Pampean/Chacoan regions of Argentina. The cytochrome b gene was successfully amplified in all Molossid and Vespertilionid species except for Eptesicus, for which we designed a new reverse primer. The resulting Bayesian phylogeny was congruent with current systematics. Cytochrome b proved useful for species-level delimitation in non-conflicting genera (Eumops, Dasypterus, Molossops) and has infrageneric resolution in more complex lineages (Eptesicus, Myotis, Molossus). We discuss four sources of incongruence that may act separately or in combination: 1) molecular processes, 2) biology, 3) limitations in identification, and 4) errors in the current taxonomy. The present study confirms the general applicability of cytochrome b -based phylogenies in eco-epidemiological studies, but its resolution and reliability depend mainly, but not solely, on the level of genetic differentiation within each bat genus.
Subject(s)
Chiroptera/genetics , Cytochromes b/genetics , DNA, Mitochondrial/genetics , Genetic Variation , Animals , Argentina , PhylogenyABSTRACT
We present two groups of cases of atypical hand, foot, and mouth disease (HFMD) caused by Coxsackievirus A6 (CV-A6) detected in Argentina in 2015. The first group involved 14 patients from Chubut province and the second group affected 12 patients from San Luis province. Molecular analysis of the complete VP1 protein gene revealed the circulation of E2 sublineage, the most predominant worldwide. To our knowledge, this is the first report of CV-A6 infections associated with atypical HFMD in Argentina and South America.
Se describen dos grupos de casos de enfermedad de mano-pie-boca (HFMD) atípica causada por el virus Coxsackie A6 (Coxsackievirus A6, CV-A6) detectados en Argentina en el año 2015. El primero de los grupos involucró a 14 pacientes de Chubut y el segundo a 12 pacientes de San Luis. El análisis molecular del gen de la proteína VP1 completa reveló la circulación del sublinaje E2, el predominante a nivel global. Hasta donde sabemos, este es el primer reporte de infecciones CV-A6 asociadas con HFMD atípica en Argentina y Sudamérica.
Subject(s)
Enterovirus/pathogenicity , Hand, Foot and Mouth Disease/etiology , Hand, Foot and Mouth Disease/microbiology , Hand, Foot and Mouth Disease/epidemiologyABSTRACT
We present two groups of cases of atypical hand, foot, and mouth disease (HFMD) caused by Coxsackievirus A6 (CV-A6) detected in Argentina in 2015. The first group involved 14 patients from Chubut province and the second group affected 12 patients from San Luis province. Molecular analysis of the complete VP1 protein gene revealed the circulation of E2 sublineage, the most predominant worldwide. To our knowledge, this is the first report of CV-A6 infections associated with atypical HFMD in Argentina and South America.
