Comparison of RT-PCR, RT-nested PCRs, and real-time PCR for diagnosis of severe fever with thrombocytopenia syndrome: a prospective study

High prevalence of dengue, Zika, and chikungunya viruses in blood donors during a dengue outbreak and an endemic period in Colombia

Objective

Arboviruses pose a challenge in ensuring the supply of pathogen-free blood components because they are not routinely screened in blood banks, and blood components from infected asymptomatic donors could be transfused. This study aimed to detect and characterize arboviral infections in Colombian blood donors.

Methods

In a cross-sectional study, the prevalence of dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses and co-infections of blood donors were compared between an epidemic period (November 2019-February 2020, n = 462) and an endemic period (November 2021-August 2022, n = 1,119). Viral RNA from each donor serum was purified, and the viruses were detected using a previously standardized multiplex hemi-nested RT-PCR protocol. Subsequently, donors who tested positive were surveyed 15 days after the detection of the virus to identify clinical characteristics related to the arboviral infection. The prevalences of each virus were presented as percentages and compared between epidemic and endemic periods.

Results

Significantly higher prevalences were found in the epidemic period compared with the endemic period for DENV (14.5 vs. 1.9%), ZIKV (7.8 vs. 0.3%), CHIKV (8 vs. 3.3%), and co-infections (4.3 vs. 0.2%). The survey response rate of positive donors in the two periods was 83/175 (47%). In total, 57% of the donors surveyed were asymptomatic. Symptomatic donors most frequently reported headache (31%), malaise (13%), arthralgia (10%), and fever/chills (8%).

Conclusion

The prevalence observed in epidemic and endemic periods was higher than that reported in other studies in the Americas. The high proportion of asymptomatic cases found, in addition to the mild and nonspecific manifestations among the symptomatic, may limit the effectiveness of the donor selection criteria used to mitigate the risk of transfusion-transmitted arboviruses.

Comparative Analysis of the Prevalence of Bovine Viral Diarrhea Virus in Cattle Populations Based on Detection Methods: A Systematic Review and Meta-Analysis

Infectious diseases of cattle, including bovine viral diarrhea (BVD), pose a significant health threat to the global livestock industry. This study aimed to investigate the prevalence and risk factors associated with bovine viral diarrhea virus (BVDV) infections in cattle populations through a systematic review and meta-analysis. PubMed, Web of Science, and Scopus were systematically searched for relevant articles reporting the prevalence of and associated risk factors in studies published between 1 January 2000 and 3 February 2023. From a total of 5111 studies screened, 318 studies were included in the final analysis. BVDV prevalence in cattle populations was estimated using various detection methods. The analysis detected heterogeneity in prevalence, attributed to detection techniques and associated risk factors. Antibody detection methods exhibited a higher prevalence of 0.43, reflecting the cumulative effect of detecting both active and past infections. Antigen detection methods showed a prevalence of 0.05, which was lower than antibody methods. A prevalence of 0.08 was observed using nucleic acid detection methods. The health status of the examined cattle significantly influenced the prevalence of BVDV. Cattle with bovine respiratory disease complex (BRDC) exhibited higher antibody (prevalence of 0.67) and antigen (prevalence 0.23) levels compared to cattle with reproductive problems (prevalence 0.13) or diarrhea (prevalence 0.01). Nucleic acid detection methods demonstrated consistent rates across different health conditions. Age of cattle influenced prevalence, with higher rates in adults compared to calves. Risk factors related to breeding and reproduction, such as natural or extensive breeding and a history of abortion, were associated with increased prevalence. Coinfections with pathogens like bovine herpesvirus-1 or Neospora caninum were linked to higher BVDV prevalence. Management practices, such as commingling, introducing new cattle, and direct contact with neighboring farms, also influenced prevalence. Herd attributes, including larger herd size, and the presence of persistently infected cattle, were associated with higher prevalence. These findings indicated the importance of detection methods and risk factors in BVDV epidemiological studies.

Advancements in the Worldwide Detection of Severe Fever with Thrombocytopenia Syndrome Virus Infection from 2009 to 2023

Severe fever with thrombocytopenia syndrome (SFTS) is a growing concern as an emerging tick-borne infectious disease originating from the SFTS virus (SFTSV), a recent addition to the Phlebovirus genus under the family of bunyaviruses. SFTS is typically identified by symptoms such as fever, thrombocytopenia, leukopenia, and gastrointestinal problems, accompanied by a potentially high case fatality rate. Thus, early and accurate diagnosis is essential for effective treatment and disease management. This review delves into the existing methodologies for SFTS detection, including pathogenic, molecular, and immunological technologies.

Accuracy of reverse-transcription polymerase chain reaction and loop-mediated isothermal amplification in diagnosing severe fever with thrombocytopenia syndrome: A systematic review and meta-analysis

Nucleic acid molecular diagnostic technology plays an important role in the detection of severe fever with thrombocytopenia syndrome (SFTS). However, no relevant reports have been published on the accuracy of reverse-transcription polymerase chain reaction (RT-PCR) and reverse-transcription loop-mediated isothermal amplification (RT-LAMP) in the diagnosis of SFTS. Thus, we conducted a meta-analysis and systematic review to evaluate the accuracy of the two methods. On June 19, 2022, we comprehensively searched the PubMed, Embase, Cochrane Library, Web of Science, Scoups, Ovid, Proquest, China National Knowledge Infrastructure Database, Wan Fang Data, Traditional Chinese Medicine Database (Sinomed), VIP Database, and Reading Showing Database for articles on nucleic acid diagnostic techniques, such as RT-PCR and RT-LAMP, used to diagnose SFTS. Statistical analysis was performed using STATA 14.0 and Meta-Disc 1.4. Sixteen articles involving 2942 clinical blood samples were included in the analysis. RT-PCR and RT-LAMP were used as index tests, whereas RT-PCR or other detection methods were used as reference standards. The pooled values for the sensitivity, specificity, positive and negative likelihood ratios of the RT-PCR test were 0.97 (95% confidence interval [CI]: 0.92-0.99), 1.00 (95% CI: 0.98-1.00), 483.87 (95% CI: 58.04-4033.76), and 0.03 (95% CI:0.01-0.08), respectively. Those for the RT-LAMP test were 0.95 (95% CI: 0.91-0.97), 0.99 (95% CI: 0.93-1.00), 111.18 (95% CI: 13.96-885.27), and 0.05 (95% CI: 0.03-0.09), respectively. Both RT-PCR and RT-LAMP have high diagnostic value in SFTS and can be applied in different scenarios for laboratory confirmation or on-site screening.

Adenovirus in fishery harbours and identification of contamination sources

Adenoviruses (AdVs) are a major cause of clinical infections and have been proposed as indicators of water quality. However, quantitative data on the environmental prevalence of AdVs is lacking. We investigated the prevalence, distribution, seasonal occurrence, quantity, and genotype of AdVs in 13 fishing harbours in Taiwan. AdVs in the water samples were isolated by membrane filtration and the AdV DNA was extracted. Next, AdVs were detected using nested polymerase chain reaction. Genotyping and phylogenetic analysis were performed to identify various AdV genotypes present in the water samples. The F species human AdV (HAdV) serotype 41 (63.6%) and C species porcine AdV (PAdV) serotype 5 (33.3%) were more prevalent than the other serotypes. The prevalence of AdVs was highest in the fall, followed by in the spring and summer. Among the fishing harbours, the highest detection rate of AdVs was observed in Yenpudongang in all seasons. However, Puoziliao was the only site at which AdVs were not detected during the study period. AdV detection at sampling sites may be correlated with sewage and livestock wastewater discharge via outflow of nearby rivers to fishing ports. Statistical analysis (Mann-Whitney U test) based on data from water quality indicators revealed that the presence of AdVs was significantly associated with the heterotrophic plate count, pH, and salinity. Human and swine population data from nearby local townships and river/drainage basins were collected from the Taiwan Central Government's website. The data were analyzed using Spearman's rank correlation coefficient to determine the relationship between the prevalence of AdVs, HAdVs, and PAdVs in fishing harbours, and microbial water quality indicators. Statistical evidence indicated that the detection levels of HAdVs and PAdVs in fishing harbours were mainly associated with human and swine populations in the corresponding river/drainage basin, respectively. Additionally, the swine population in the river/drainage basin was positively correlated with microbial water quality indicators.