Severe Acute Hepatitis Outbreaks Associated with a Novel Hepacivirus in Rhizomys pruinosus in Hainan, China

Talaromyces Marneffei infections in five human immunodeficiency virus-negative patients with the history of predation on wild bamboo rats (Rhizomys spp) - a case series

BACKGROUND

Talaromycosis is an aggressive and life-threatening disease, caused by the pathogen Talaromyces marneffei (T. marneffei) which was first isolated from the bamboo rats (Rhizomys sinensis). T. marneffei was traditionally known for its high incidence and mortality rates in human immunodeficiency virus (HIV) patients. Epidemiological data reveal a concerning upward trend of infections among HIV-negative individuals, including immunocompetent hosts. At the meantime, although the bamboo rats have been reported to be associated with T. marneffei infection, there is a noticeable rising trend of the bamboo rats hunting and farming industry. Public awareness regarding the zoonotic transmission risks associated with these rodents remains limited.

CASE PRESENTATION

We report five cases of T. marneffei infection occurring within a single year, all involving individuals with a history of hunting wild bamboo rats (Rhizomys spp., likely Rhizomys sinensis). All five patients underwent HIV testing upon admission, with uniformly negative results. Notably, other immunodeficiency diseases, chronic comorbidities or prior immunosuppressive therapy were not found in these patients. The clustered emergence of these cases-affecting immunocompetent individuals within neighboring geographic areas over a brief timeframe, all sharing exposure through bamboo rat hunting-warrants detailed characterization. We herein present clinical profiles of these five cases.

CONCLUSIONS

These cases demonstrate epidemiological associations between contact with wild bamboo rats and T. marneffei infections in immunocompetent individuals. The atypical clinical symptoms and variable imaging manifestations of T. marneffei infection may lead to increased underdiagnosis and misdiagnosis. Systematic implementation of exposure history, particularly documenting contact with wild animals for patients with pulmonary infection to make a timely diagnosis. This study also underscores the urgent need for public awareness regarding the potential risks of T. marneffei infections associated with hunting wild bamboo rats and the bamboo rat farming industry.

Generation and epitope mapping of novel neutralizing monoclonal antibodies against glycoprotein E2 of CSFV

Classical swine fever virus (CSFV) is a highly contagious and economically important pathogen threatening pig industry worldwide, the envelope glycoprotein E2 of CSFV is the dominant antigen inducing strong antiviral neutralizing immunity. In this study, 7 monoclonal antibodies (mAbs) with neutralizing potency were generated using E2 protein of CSFV Shimen strain (SM) expressed by eukaryotic cells. Their reactivity with 116 CSFV strains in cell cultures and E2 proteins of 10 subgenotypes in western blots showed different CSFV spectrums they recognized. Of them, three (HCL-001, HCL-005 and HCL-010) reacted with all CSFV subgenotypes, while HCL-014 and HCL-002 reacted with most CSFV strains, except for some variants in genotype 2.3. In contrast, mAb HCL-009 reacted only with a few subgenotype 1.1 strains including SM, field strains and some vaccine strains. Interestingly, mAb HCL-018 reacted only with SM and field subgenotype 1.1 strains, not with any vaccine strains. Further epitope mapping using chimeric and site-directed mutated E2 proteins showed that HCL-001, HCL-005 and HCL-010 recognized a conservative epitope motif 143SPT145,L147, and HCL-002 recognized a conformational epitope with key aa motifs of 95GDD97,157RX(D/E)K(R)XFXXR164. HCL-014 recognized a new conservative epitope with key aa motifs of 41D,58XNVVXRR64. HCL-009 and HCL-018 recognized the epitope with key aa motifs of 36D,40ND41,45KXI47 and 69LHXGXLLT76, respectively. Taken together, present study has provided not only new insights into the antigenic structure of E2 protein, but also key reagents for antigenic characterization of CSFV strains and development of antibody assay for evaluation of the vaccination efficacy.

Viromics-based precision diagnosis of reproductive abnormalities in cows reveals a reassortant Akabane disease virus

BACKGROUND

At the end of 2021, an epidemic of reproductive abnormalities in cows occurred in Jilin Province, China, posing an urgent need for a rapid diagnosis.

RESULTS

To identify the cause of the disease, a total of 172 samples were collected from 21 dead calves and 45 aborting or pregnant cows in 10 farms across the province. Routine PCR or RT-PCR detection did not find any common abortion-related agents. We then employed the viromics-based precision diagnosis method to analyze these samples, and the read-based annotation showed signals of an Akabane disease virus (AKAV) in some libraries. To further identify the virus, nested RT-PCR detection revealed that 52.3% (11/21) of dead calves and 26.6% (12/45) of cows were positive for the virus. Phylogenetic analysis of the partial fragments showed that the S segment of the virus was 100% identical to the Chinese strain TJ2016, but its M and L segments shared 94.3% and 96.5% identities with an Israeli strain.

CONCLUSIONS

The viromic and molecular results suggested that these animals were infected with a reassortant AKAV. Coupled with the clinical signs, the virus should be responsible for the epizootic, highlighting that molecular and serological surveys of the virus in cows during early pregnancy, as well as ecological investigation in its arthropod vectors, are necessary.

Molecular epizootiology of porcine reproductive and respiratory syndrome virus in the Xinjiang Uygur Autonomous Region of China

Rapid evolution of porcine reproductive and respiratory syndrome virus (PRRSV) is the bottleneck for effective prevention and control of PRRS. Thus, understanding the prevalence and genetic background of PRRSV strains in swine-producing regions is important for disease prevention and control. However, there is only limited information about the epizootiological situation of PRRS in the Xinjiang Uygur Autonomous Region, China. In this study, blood or lung tissue samples were collected from 1,411 PRRS-suspected weaned pigs from 9 pig farms in Changji, Shihezi, and Wujiaqu cities between 2020 and 2022. The samples were first tested by RT-quantitative PCR, yielding a PRRSV-2 positive rate of 53.6%. Subsequently, 36 PRRSV strains were isolated through initial adaptation in bone marrow-derived macrophages followed by propagation in grivet monkey Marc-145 cells. Furthermore, 28 PRRSV-positive samples and 20 cell-adapted viruses were selected for high-throughput sequencing (HTS) to obtain the entire PRRSV genome sequences. Phylogenetic analysis based on the nucleotide sequences of the ORF5 gene of the PRRSV strains identified in this study grouped into sub-lineages 1.8 and 8.7 the former being the dominant strain currently circulating in Xinjiang. However, the NSP2 proteins of the Xinjiang PRRSV strains shared the same deletion patterns as sub-lineage 1.8 prototype strain NADC30 with the exception of 4 strains carrying 2-3 additional amino acid deletions. Further analysis confirmed that recombination events had occurred in 27 of 37 PRRSVs obtained here with the parental strains belonging to sub-lineages 1.8 and 8.7, lineages 3 and 5, with the recombination events having occurred most frequently in the 5' and 3' termini of ORF1a and 5' terminus of ORF1b.

Outbreak of piglet diarrhea associated with a new reassortant porcine rotavirus B

Rotavirus B (RVB) is a causative agent leading to acute viral gastroenteritis diarrhea in both children and young animals, and has been commonly detected in piglets. In order to determine the causative agent of diarrheal outbreak occurring in December 2022 in piglets from a pig herd in Luoyang, Henan province of China, four common viral pathogens causing piglet diarrhea-three coronaviruses and rotavirus A (RVA) were first tested and found negative, therefore metagenomic sequencing was performed to explore other potential pathogens in the diarrheal samples. Unexpectedly, the most abundant viral reads mapped to RVB, and were de novo assembled to complete 11 viral gene segments. Sequence comparisons revealed that 5 gene segments encoding VP1, VP2, VP3, NSP3 and NSP4 of RVB strain designated as HNLY-2022 are most closely related to RVB strains derived from herbivores with low nucleotide similarities of 65.7-75.3%, and the remaining segments were relatively close to porcine RVB strains with the VP4 gene segment showing very low nucleotide identity (65.0%) with reference strains, indicating HNLY-2022 is a new reassortant RVB strain. Based on the previously proposed genotype classification criterion, the genotype constellation of RVB strain HNLY-2022 is G6-P[6]-I4-R6-C6-M6-A7-N5-T7-E5-H4 with more than half of the genotypes (P[6], R6, C6, M6, T7 and E5) newly reported. Therefore, the new reassortant RVB strain is the likely causative agent for the diarrheal outbreak of piglets occurred in China and more epidemiological studies should be conducted to monitor the spread of this newly identified porcine RVB strain.