RT-PCR For Detection Of Virus Research Articles

Serosurvey in Two Dengue Hyperendemic Areas of Costa Rica Evidence Active Circulation of WNV and SLEV in Peri-Domestic and Domestic Animals and in Humans.

Costa Rica harbors several flaviviruses, including Dengue (DENV), Zika (ZIKV), West Nile virus (WNV), and Saint Louis encephalitis virus (SLEV). While DENV and ZIKV are hyperendemic, previous research indicates restricted circulation of SLEV and WNV in animals. SLEV and WNV seroprevalence and high transmission areas have not yet been measured. To determine the extents of putative WNV and SLEV circulation, we sampled peri-domestic and domestic animals, humans, and mosquitoes in rural households located in two DENV and ZIKV hyperendemic regions during the rainy and dry seasons of 2017-2018 and conducted plaque reduction neutralization test assay for serology (PRNT) and RT-PCR for virus detection. In Cuajiniquil, serological evidence of WNV and SLEV was found in equines, humans, chickens, and wild birds. Additionally, five seroconversion events were recorded for WNV (2 equines), SLEV (1 human), and DENV-1 (2 humans). In Talamanca, WNV was not found, but serological evidence of SLEV circulation was recorded in equines, humans, and wild birds. Even though no active viral infection was detected, the seroconversion events recorded here indicate recent circulation of SLEV and WNV in these two regions. This study thus provides clear-cut evidence for WNV and SLEV presence in these areas, and therefore, they should be considered in arboviruses differential diagnostics and future infection prevention campaigns.

Molecular evidence of schmallenberg virus associated by ovine abortion with fetal anomalies in Nineveh province, Iraq

In late 2011, Schmallenberg virus (SBV) was observed in Germany using genomic analysis. The virus is transmitted through insect vectors and vertically from females to their offspring across the placenta. In adult sheep, the virus causes a short viremia followed by lethargy, abortion, and dystocia when giving birth to malformed lambs. RT-PCR for virus detection and commercial ELISAs for antibody detection were rapidly developed. No previous studies have detected SBV in sheep in Nineveh province. Thus, this study intended to investigate the presence of SBV in aborted fetuses and describe the macroscopic lesions. Fifteen aborted lambs aged between 70 to 135 days were collected between October 2021 and January 2022. Brain stem, spinal cord, spleen, liver, lung, and abdominal fluid were collected and stored at -20ºC for molecular analysis. Viral RNA was extracted from these collected samples, and reverse transcription was performed in one step. RT-PCR was applied to amplify the SBV gene (S segment). Three of fifteen lambs showed marked malformations in the vertebral column, arthrogryposis, hydranencephaly, cerebral and cerebellar hypoplasia, and porencephaly. SBV was detected in malformed aborted lambs by RT-PCR with 474bp product size. These findings indicate that SBV causes abortion with malformations. Further studies on this topic should include the isolation and characterization of the virus and SBV epidemiology.

Identification and Characterization ofWheat Streak Mosaic VirusIsolates in Wheat-Growing Areas in Brazil

Wheat streak mosaic virus(WSMV—Potyviridae,Tritimovirus), transmitted by the eriophyid miteAceria tosichellaKeifer (Acari:Eriophyidae), was considered a quarantine pest in South America. Since the first report of virus in Argentina, the vector has been found in Argentina, Uruguay and Brazil. The objective of this work was to determine the occurrence of WSMV in Brazil and characterize isolates from wheat-growing areas. Between 2009 and 2011, a total of 40 samples collected in wheat (Triticum aestivum) growing areas, where the presence of the mite was previously related, were tested by RT-PCR for virus detection. Six isolates of WSMV were obtained and characterized by sequencing. Two of them had their host range determined. The Brazilian WSMV isolates clustered in clade D are closely related to the Argentine isolate Arg2 (FJ348359). As expected, isolates were unable to infect dicotyledons plants. They caused mosaic inTriticum aestivum,Hordeum vulgare,Secale cereale, ×Triticosecale, andZea mays, and they were also able to infectAvena sativa. The presence of WSMV in wheat-growing areas of the Brazilian state Rio Grande do Sul was confirmed, possibly having been introduced from a common source and/or direct vector bearing virus migration from Argentina.

Prevalence study of Bovine viral diarrhea virus by evaluation of antigen capture ELISA and RT-PCR assay in Bovine, Ovine, Caprine, Buffalo and Camel aborted fetuses in Iran

Bovine viral diarrhea virus is a pestivirus in the family Flaviviridae that cause abortions and stillbirths in livestock and its traditional diagnosis is based on cell culture and virus neutralization test. In this study, for more sensitive, specific detection and determined the prevalence of virus in aborted Bovine, Ovine, Caprine, Buffalo and Camel fetuses the antigen capture ELISA and RT-PCR were recommended. From the total of 2173 aborted fetuses, 347 (15.96%) and 402 (18.49%) were positive for presence of Bovine viral diarrhea virus by antigen capture ELISA and RT-PCR respectively. Statistical analysis of data showed significant differences between ELISA and RT-PCR for detection of virus in aborted fetuses.These results indicate a high presence of this pathogen in Iran and that RT- PCR is considerably faster and more accurate than ELISA for identification of Bovine viral diarrhea virus.To our knowledge the Camels and Bovine are the most resistant and sensitive to Bovine viral diarrhea's abortions respectively and the prevalence of virus in Caprine is more than Ovine aborted fetuses. This study is the first prevalence report of Bovine viral diarrhea virus in aborted Bovine, Ovine, Caprine, Buffalo and Camel fetuses by evaluation of ELISA and RT-PCR in Iran.

Molecular monitoring of causative viruses in child acute respiratory infection in endemo-epidemic situations in Shanghai

Background: Numerous viruses are responsible for respiratory infections; however, both their distribution and genetic diversity, in a limited area and a population subgroup, have been studied only rarely during a sustained period of time. Methods: A 2-year surveillance program of children presenting with acute respiratory infections (ARIs) was carried out to characterize the viral etiology and to assess whether using gene amplification and sequencing could be a reliable approach to monitor virus introduction and spread in a population subgroup. Results: Using multiplex RT-PCR, 15 different respiratory viruses were detected within the 486 nasopharyngeal positive samples collected among 817 children aged <9-year old who presented with ARI during October 2006 to September 2008. A single virus was detected in 373 patients (45.7%), and two to four viruses in 113 patients (13.8%). The most frequent causative viruses were respiratory syncytial virus (RSV) (24.7%), human bocavirus (24.5%), and human rhinovirus (HRV) (15%). RSV was more prevalent in winter and among young infants. Cases of seasonal influenza A and B viruses were reported mainly in January and August. An increase in adenovirus infection was observed during the spring of the second year of the study. Sequence analyses showed multiple introductions of different virus subtypes and identified a high prevalence of the newly defined HRV-C species. A higher viral incidence was observed during the winter of 2008, which was unusually cold. Conclusions: This study supports the usefulness of multiplex RT-PCR for virus detection and co-infection, and for implementation of a molecular monitoring system for endemic and epidemic viral respiratory infections.

Clinical manifestations and laboratory assessment in an enterovirus 71 outbreak in southern Taiwan.

An epidemic of enterovirus 71 (EV71) infection compatible with hand, foot and mouth disease and associated with high morbidity and mortality occurred in Taiwan in 1998. We recruited 90 patients (50 males, 40 females) with definite EV71 infections for clinical and laboratory analysis. The neurological signs and symptoms, all of which occurred during the febrile period, in patients with central nervous system (CNS) involvement (aseptic meningitis, encephalitis or myelitis) were myoclonic jerks (23/33), vomiting (10/33), ataxia (7/33), lethargy (6/33), seizure (4/33) and tremor (2/33). Patients with CNS involvement had longer durations of fever (4.6+/-0.2 vs. 3.1+/-0.3 d; p <0.01) and a higher white blood cell count (12,512+/-658 vs. 10,607+/-409 cells/mm3; p = 0.01) than patients without CNS involvement. The case fatality rate in patients with CNS involvement was 4/33 (12%), whereas no fatalities (0/57) occurred in patients without CNS involvement. Six of 11 patients subjected to MRI showed a high intensity T2-weighted signal in the brainstem. A nested fluorescent RT-PCR for detection of virus in throat and stool specimens showed higher sensitivity than viral culture. Viremia was detectable using RT-PCR in 20% of cases (3/15), whereas no virus was isolated from culture or detected by RT-PCR in cerebrospinal fluid.