Newly Characterized Porcine Epidemic Diarrhea Virus GII Subtype Strain

Diarrhea outbreaks in piglets on pig farms are commonly attributed to porcine epidemic diarrhea virus (PEDV) infection. This research analyzed the S gene prevalence variation and recombination patterns in PEDV GII strains. Throughout the previous two years, 172 clinical samples of piglet diarrhea have been collected, from which 24 PEDV isolates have been isolated. Analysis of the evolutionary relationships among all 24 S genes revealed that 21 were most closely related to strains within the GII-a subgroup. The 2 isolates grouped into one clade with the GII-b subgroup. According to the mutation analysis of the amino acids (aa) that encode the S protein, 43 of the common aa in strains of the GII subtype were found to have undergone a change in polarity or charge, and 36 of these aa had a mutation frequency of more than 90%. Three different aa mutation sites were identified as exclusive to GII-a subtype strains. The genomes of three PEDV isolates were sequenced, and the resulting range in genome length was 28,035−28,041 nt. The results of recombination analysis showed that the SD1 isolate is a novel strain recombinant from the foreign S-INDEL strain and a domestic GII subtype strain. Based on the findings, the PEDV GII-a strain has been the most circulating strain in several parts of China during the previous two years. Our study reveals for the first time the unique change of aa mutations in the S protein of the GII-a subtype strain and the new characteristics of the recombination of foreign strains and domestic GII subtype strains, indicating that it is crucial to monitor the epidemic dynamics of PEDV promptly to prevent and control the occurrence of PED effectively.

Differences in and Factors Related to Willingness to Provide Care to Patients with Suspected or Confirmed COVID-19 in Long-Term Care Facilities.

The coronavirus disease 2019 (COVID-19) pandemic has exerted tremendous effects on the residents of and caregivers at long-term care facilities (LTCF). The combination of a vulnerable, aged population, staffing shortages, and inadequate resources in LTCF will cause a great negative impact in these sectors. Addressing the caregiver's lack of interest in providing care for patients with COVID-19 is a great challenge for institutional managers. The primary objective of this study was to analyze the factors related to the willingness of personnel at LTCF to provide care to patients with COVID-19. This was a cross-sectional study in which personnel from 10 LTCF were recruited as participants through convenience sampling and completed structured questionnaires. A total of 500 questionnaires were distributed and 385 valid questionnaires were recovered, posting a response rate of 77%. A statistical analysis was performed using SPSS 22.0. The results of the survey revealed that only 30% of the participants were willing to provide care to patients with COVID-19; 23% more of the participants were willing to provide such care if their institutions provided sufficient PPE. Regarding other conditions, 31.5% and 76% of the participants expressed that they would be willing to provide such care if their compensation were increased and working hours were reduced. In the univariate analysis, the willingness of participants with different characteristics (job categories, years of holding a professional certificate, job location type, monthly income, experience with caring for patients with confirmed COVID-19, and completion of training related to communicable disease control) varied significantly (p < 0.05). Furthermore, in the logistic regression analysis, several demographic and professional characteristics (education level, job category, number of patients served daily, and monthly income) were significantly correlated with willingness to provide care to patients with COVID-19 (p < 0.05). On the basis of these findings, the LTCF should securitize the associated factors of care wiliness in personnel to eliminate the difference of the willingness to provide care to patients with suspected or confirmed COVID-19.

Porcine epidemic diarrhea virus strain FJzz1 infection induces type I/III IFNs production through RLRs and TLRs-mediated signaling.

Interferons (IFNs) including type I/III IFNs are the major components of the host innate immune response against porcine epidemic diarrhea virus (PEDV) infection, and several viral proteins have been identified to antagonize type I/III IFNs productions through diverse strategies. However, the modulation of PEDV infection upon the activation of the host's innate immune response has not been fully characterized. In this study, we observed that various IFN-stimulated genes (ISGs) were upregulated significantly in a time- and dose-dependent manner in LLC-PK1 cells infected with the PEDV G2 strain FJzz1. The transcriptions of IRF9 and STAT1 were increased markedly in the late stage of FJzz1 infection and the promotion of the phosphorylation and nuclear translocation of STAT1, implicating the activation of the JAK-STAT signaling pathway during FJzz1 infection. In addition, abundant type I/III IFNs were produced after FJzz1 infection. However, type I/III IFNs and ISGs decreased greatly in FJzz1-infected LLC-PK1 cells following the silencing of the RIG-I-like receptors (RLRs), including RIG-I and MDA5, and the Toll-like receptors (TLRs) adaptors, MyD88 and TRIF. Altogether, FJzz1 infection induces the production of type-I/III IFNs in LLC-PK1 cells, in which RLRs and TLRs signaling pathways are involved, followed by the activation of the JAK-STAT signaling cascade, triggering the production of numerous ISGs to exert antiviral effects of innate immunity.

Distribution of SARS-CoV-2 RNA signal in a home with COVID-19 positive occupants.

Although many COVID-19 patients isolate and recover at home, the dispersal of SARS-CoV-2 onto surfaces and dust within the home environment remains poorly understood. To investigate the distribution and persistence of SARS-CoV-2 in a home with COVID-19 positive occupants, samples were collected from a household with two confirmed COVID-19 cases (one adult and one child). Home surface swab and dust samples were collected two months after symptom onset (and one month after symptom resolution) in the household. The strength of the SARS-CoV-2 molecular signal in fomites varied as a function of sample location, surface material and cleaning practices. Notably, the SARS-CoV-2 RNA signal was detected at several locations throughout the household although cleaning appears to have attenuated the signal on many surfaces. Of the 24 surfaces sampled, 46% were SARS-CoV-2 positive at the time of sampling. The SARS-CoV-2 concentrations in dust recovered from floor and HVAC filter samples ranged from 104 to 105 N2 gene copies/g dust. While detection of viral RNA does not imply infectivity, this study confirms that the SARS-CoV-2 RNA signal can be detected at several locations within a COVID-19 isolation home and can persist after symptoms have resolved. In addition, the concentration of SARS-CoV-2 (normalized per unit mass of dust) recovered in home HVAC filters may prove useful for estimating SARS-CoV-2 airborne levels in homes. In this work, using the quantitative filter forensics methodology, we estimated an average integrated airborne SARS-CoV-2 concentration of 69 ± 43 copies/m3. This approach can be used to help building scientists and engineers develop best practices in homes with COVID-19 positive occupants.