Biology subjects

Antunes Eisen, A. K.

Publications and source records attributed to Antunes Eisen, A. K..

3 recordsLinked to original sources

bioRxiv2020

Pre-treatment of the clinical sample with Proteinase K allows detection of SARS-CoV-2 in the absence of RNA extraction

COVID-19 (Coronavirus Disease 2019) outbreak was declared a pandemic, by World Health Organization, on March 11, 2020. Viral detection using RT-qPCR has been among the most important factors helping to control local spread of SARS-CoV-2 and it is considered the "gold standard" for diagnosis. Nevertheless, the RNA extraction step is both laborious and expensive, thus hampering the diagnosis in many places where there are not laboratory staff of funds enough to contribute for diagnosis efforts. Thus, the need to simplify procedures, reduce costs of the techniques used, and expand the capacity of the number of diagnostics of COVID-19 is imperative. In this study, detection of SARS-CoV-2 in the absence of RNA extraction has been successfully achieved through pre-treatment of the clinical sample with Proteinase K. The results show that only the use of proteinase K, without the need to perform the whole standard protocol for sample extraction and purification, can be an efficient technique for the diagnosis of COVID-19, since 91% of the samples matched the results with the standard procedure, with an average increase of 5.64 CT in the RT-qPCR.

microbiology↗

bioRxiv2020

SARS-CoV2 quantification using RT-dPCR: a faster and safer alternative to assist viral genomic copies assessment using RT-qPCR

In this study, serial dilutions of SARS-CoV 2 RNA extract were tested using RT-dPCR using three different primer-probe assays aiming SARS-CoV 2 nucleocapsid coding region. Narrower confidence intervals, indicating high quantification precision were obtained in 100 and 1000-fold serial dilution and RT-dPCR results were equivalent between different assays in the same dilution. High accuracy of this test allowed conclusions regarding the ability of this technique to evaluate precisely the amount of genomic copies present in a sample. We believe that this fast and safe method can assist other researchers in titration of SARS-CoV2 controls used in RT-qPCR without the need of virus isolation.

molecular biology↗

bioRxiv2019

Detection of a novel African-lineage-like Zika virus naturally infecting free-living neotropical primates in Southern Brazil

Mosquito borne flaviviruses cause a series of important diseases in humans and animals. These viruses are maintained in cycles involving replication in mosquito and in vertebrate hosts. Most natural hosts are vertebrate animals living in sylvatic or peridomestic environments. Human contact with these environments may result in host shifts that lead to the establishment of urban transmission cycles. Zika virus is a Flavivirus that persists in nature in a transmission cycle involving non-human primates (NHP). Its recent emergence in Brazil has shed light upon the importance of surveying this agent in Brazilian sylvatic environments. Here we present histopathological and molecular evidence that free ranging howler monkeys (Alouatta guariba) in Southern Brazil are infected by ZIKV closely related to African lineage MR766. Nine NHP were nested RT-PCR positive for ZIKV RNA. Sequence analysis revealed 96 to 98% identity to ZIKV MR766 and 85% identity to ZIKV P6-740, the current epidemic strain. The affected howler monkeys presented discrete inflammatory infiltrates in several tissues and immunohistochemichal (IHC) labeling of viral antigen was observed in placenta. These findings point to the circulation of African lineage Zika virus in the Americas in non-human primates. And raises the possibility that ZIKV was introduced into the Americas on more than one occasion.

microbiology↗