Establishment and application of ERA-LFD method for rapid detection of feline calicivirus.

Feline calicivirus (FCV) has a single-stranded, positive-sense RNA genome, and it is responsible for many infectious respiratory diseases in cats. In addition, more worryingly, highly virulent strains of FCV can cause high mortality in felines. Therefore, a rapid and reliable diagnosis tool plays an important role in controlling the outbreak of FCV. In this study, enzymatic recombinase amplification (ERA) assay combined with lateral flow dipstick (LFD) was developed for the detection of FCV, targeting a relatively conversed position of FCV-ORF1. The results showed that the optimal reaction condition was at 40 °C for 30 min. ERA-LFD method was highly sensitive with the detection limit as low as 3.2 TCID50 of FCV RNA per reaction. The specificity analysis demonstrated no cross-reactivity with feline parvovirus (FPV), feline herpesvirus (FHV) and feline infectious peritonitis virus (FIPV). ERA-LFD was highly repeatable and reproducible, with the intra-assay and inter-assay coefficients of variation for this method both less than 7%. The general test showed that all the recombinant plasmids with known mutant sites and FCV strains with different mutant sites stored in our laboratory were all detected by this method. Of the 23 samples, 14 samples were tested positive for FCV by ERA-LFD and RT-qPCR, respectively. In summary, ERA-LFD assay was a fast, accurate and convenient diagnosis tool for the detection of FCV. KEY POINTS: • The detection principle of ERA-LFD was introduced. • Almost all the currently known FCV strains can be detected. • ERA-LFD is easy to operate and can be used for field detection.

Rotavirus and Norovirus Infections in Children Under 5 Years Old with Acute Gastroenteritis in Southwestern China, 2018-2020.

OBJECTIVE: Rotaviruses and noroviruses are important causes of acute gastroenteritis in children. While previous studies in China have mainly focused on rotavirus, we investigated the incidence of norovirus in addition to rotavirus in Southwestern China. METHODS: From January 2018 to December 2020, cases of rotavirus or norovirus infections among children under five ages with acute gastroenteritis were evaluated retrospectively. RESULTS: The detection rate of rotavirus was 24.5% (27,237/111,070) and norovirus was 26.1% (4649/17,797). Among 17,113 cases submitted for dual testing of both rotavirus and norovirus, mixed rotavirus/norovirus infections were detected in 5.0% (859/17,113) of cases. While there was no difference in norovirus incidence in outpatient compared to hospitalized cases, rotavirus was detected two times more in outpatients compared to hospitalized cases (26.6% vs.13.6%; P < 0.001). Both rotavirus and norovirus infections peaked in children aged 12-18 months seeking medical care with acute gastroenteritis (35.6% rotavirus cases; 8439/23,728 and 32.5% norovirus cases; 1660/5107). Rotavirus infections were frequent between December and March of each year while norovirus was detected earlier from October to December. Our results showed significant correlation between virus detection and environmental factors such as average monthly temperature but not relative humidity. In addition, we observed a reduction in the detection rates of rotavirus and norovirus at the beginning of the SARS-CoV-2 pandemic in 2020. CONCLUSION: Our results indicate that rotavirus and norovirus are still important viral agents in pediatric acute gastroenteritis in Southwestern China.

Differential impact of the COVID-19 pandemic on laboratory reporting of norovirus and Campylobacter in England: A modelling approach.

BACKGROUND: The COVID-19 pandemic has impacted surveillance activities for multiple pathogens. Since March 2020, there was a decline in the number of reports of norovirus and Campylobacter recorded by England's national laboratory surveillance system. The aim is to estimate and compare the impact of the COVID-19 pandemic on norovirus and Campylobacter surveillance data in England. METHODS: We utilised two quasi-experimental approaches based on a generalised linear model for sequential count data. The first approach estimates overall impact and the second approach focuses on the impact of specific elements of the pandemic response (COVID-19 diagnostic testing and control measures). The following time series (27, 2015-43, 2020) were used: weekly laboratory-confirmed norovirus and Campylobacter reports, air temperature, conducted Sars-CoV-2 tests and Index of COVID-19 control measures stringency. RESULTS: The period of Sars-CoV-2 emergence and subsequent sustained transmission was associated with persistent reductions in norovirus laboratory reports (p = 0.001), whereas the reductions were more pronounced during pandemic emergence and later recovered for Campylobacter (p = 0.075). The total estimated reduction was 47% - 79% for norovirus (12-43, 2020). The total reduction varied by time for Campylobacter, e.g. 19% - 33% in April, 1% - 7% in August. CONCLUSION: Laboratory reporting of norovirus was more adversely impacted than Campylobacter by the COVID-19 pandemic. This may be partially explained by a comparatively stronger effect of behavioural interventions on norovirus transmission and a relatively greater reduction in norovirus testing capacity. Our study underlines the differential impact a pandemic may have on surveillance of gastrointestinal infectious diseases.

Norovirus Infections Drop 49% in the United States with Strict COVID-19 Public Health Interventions.

Norovirus is a substantial burden on the U.S. We compared norovirus outbreaks before and during COVID-19. There were fewer norovirus outbreaks during COVID-19 compared to a similar time period in 2019 (326 versus 638, P<0.001). CONCLUSION: COVID-19 public health interventions may be considered to decrease the burden of norovirus. This demonstrates the ability of more restrictive interventions to decrease other outbreaks of known or emerging viruses.

[SARS-CoV-2, influenza and norovirus infection : A direct epidemiologic comparison]. / SARS-CoV-2, Influenza und Norovirus : Die Klinikperspektive im Vergleich.

BACKGROUND: Hospitalization rates (HR), emergency care prevalence (ECP) and case fatality proportions (CFP) of hospitalized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients in one municipality have not been studied, including how these differ from other pandemic or seasonal viral diseases, such as influenza A/B or norovirus. These analyses and their comparison with negative-tested hospitalized patients are the purpose of the present study. METHODS: A total of 67,000 cases of hospitalized patients of a tertiary care hospital and data of the regional health institute were analyzed to calculate HR, ECP and CFP of SARS-CoV­2, influenza A/B and norovirus genotype 1/2. RESULTS: In the city and district of Fürth (Germany), 824 persons (0.34%) tested SARS-CoV-2-positive through 7 May 2020, 162 of whom (19.7%) were hospitalized. Furthermore, 48 out of 91 patients died in hospital (CFP 11.0%). During the flu/norovirus season 2019/2020 992 inhabitants were flu-positive and 135 norovirus-positive, of whom 202 (20.3%) and 125 (91.9%), respectively, were hospitalized. The ECPs were 4.1%, 2.0% and 0.6%. The CFPs of the SARS-CoV-2-, influenza- and norovirus-positive hospital cohort were 29.1%, 3.0% and 1.6%, while CFPs of the negative-tested were 5.9%, 4.8% and 6.9% with an in-hospital mortality of 2.1% for 2020. CONCLUSIONS: While HRs of SARS-CoV­2 and influenza were similar, CFPs differ significantly. CFPs of negative-tested patients were comparable between the three infectious diseases.