ABSTRACT
Yellow Fever virus (YFV) is an important human pathogen in tropical areas of Africa and South America. Although an efficient vaccine is available and has been used since the early 1940s, sylvatic YFV transmission still occurs in forested areas where anthropogenic actions are present, such as mineral extraction, rearing livestock and agriculture, and ecological tourism. In this context, two distinct techniques based on the RT-PCR derived method have been previously developed, however both methods are expensive due to the use of thermo cyclers and labeled probes. We developed isothermal genome amplification, which is a rapid, sensitive, specific and low cost molecular approach for YFV genome detection. This assay used a set of degenerate primers designed for the NS1 gene and was able to amplify, within 30 min in isothermal conditions, the YFV 17D vaccine strain derived from an African wild prototype strain (Asibi), as well as field strains from Brazil, other endemic countries from South and Central America, and the Caribbean. The generic RT-LAMP assay could be helpful for YFV surveillance in field and rapid response during outbreaks in endemic areas.
Subject(s)
Nucleic Acid Amplification Techniques/methods , Viral Nonstructural Proteins/genetics , Yellow fever virus/isolation & purification , Africa , Base Sequence , Caribbean Region , Central America , DNA Primers , Humans , Molecular Sequence Data , Population Surveillance/methods , South America , Yellow Fever/virologyABSTRACT
We report here the first complete genome sequence of a Changuinola virus (CGLV) serotype Irituia virus (BE AN 28873) isolated from a wild rodent (Oryzomys goeldi) in the municipality of Ipixuna, State of Pará, northern Brazil. All genome segments showed similarity with those belonging to members of the genus Orbivirus, family Reoviridae.
ABSTRACT
Yellow fever virus (YFV), a member of the family Flaviviridae, genus Flavivirus is endemic to tropical areas of Africa and South America and is among the arboviruses that pose a threat to public health. Recent outbreaks in Brazil, Bolivia, and Paraguay and the observation that vectors capable of transmitting YFV are presenting in urban areas underscore the urgency of improving surveillance and diagnostic methods. Two novel methods (RT-hemi-nested-PCR and SYBR(®) Green qRT-PCR) for efficient detection of YFV strains circulating in South America have been developed. The methods were validated using samples obtained from golden hamsters infected experimentally with wild-type YFV strains as well as human serum and tissue samples with acute disease.
Subject(s)
Molecular Diagnostic Techniques/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Virology/methods , Yellow Fever/diagnosis , Yellow fever virus/isolation & purification , Animals , Cricetinae , Humans , Mesocricetus , Serum/virology , South America , Yellow Fever/virology , Yellow fever virus/geneticsABSTRACT
Various assays have been developed to diagnose dengue virus infection, relying on techniques from the fields of serology and molecular biology. Many of these assays have been successful, but there is still an urgent need for accurate, simple and rapid diagnostic assays to diagnose dengue virus infection and to assist in patient management. Using a panel of well-characterized sera and a collection of retrospective samples obtained during the dengue epidemics that occurred in Belém, Brazil, between 2002 and 2009, a modified immunoglobulin M-specific capture enzyme-linked immunosorbent assay (Rapid-MAC-ELISA) was evaluated and compared with the "gold standard" MAC-ELISA, in order to assess the specificity, sensitivity, stability, reproducibility and cost-effectiveness of this new assay. These results demonstrated that the Rapid-MAC-ELISA is comparable to the MAC-ELISA in terms of sensitivity and specificity and is highly reproducible; additionally, it is easily performed, less expensive than other available formats and can be completed within three hours. Furthermore, the Rapid-MAC-ELISA can be used for the diagnosis of dengue virus infections in resource-limited areas where dengue is endemic.
