Phylogenetic analysis and evolution of feline bocavirus in Anhui Province, eastern China

Feline bocaviruses found in Thailand have undergone genetic recombination for their evolutions

Feline bocaviruses (FBoVs) have been discovered for a decade and are often detected in feces, possibly associated with diarrhea in cats. Studies on FBoV evolution remain limited and have mainly focused on prevalence and genetic characterization. Although genetic recombination serves as a potential mechanism in bocavirus evolution, research on this process for FBoVs has been scarce. In this study, we characterized 19 complete coding sequences of FBoVs obtained from Thai cats, revealing that FBoV-1, -2, and -3 were endemic in Thailand. Genetic characterizations showed that most Thai FBoVs were closely related to previously detected strains in Thailand and China. Recombination analyses indicated intragenic, intraspecies recombination in all FBoV species, with recombination breakpoints commonly found in the NP1 and VP1/2 genes, highlighting these genes may be hotspots for FBoV recombination. However, no interspecies recombination was detected. Selective pressure analysis of various FBoV genes revealed that these viruses underwent purifying selection. Although the VP1/2 gene of all FBoV species was under the strongest negative selection pressure, positive selection sites were only found in FBoV-1 and FBoV-3. This study is the first to identify natural recombination in FBoV-2 and FBoV-3 and provides evidence that genetic recombination is a potential driver of FBoV evolutions. Additionally, this study offers up-to-date information on the genetic characteristics, evolutionary dynamics, and selective pressure status of FBoVs, which should be continuously monitored.

Epidemiology and genotypic diversity of feline bocavirus identified from cats in Harbin, China

Feline bocavirus (FBoV) is a globally distributed linear, single-stranded DNA virus infect cats, currently classified into three distinct genotypes. Although FBoV can lead to systemic infections, its complete pathogenic potential remains unclear. In this study, 289 blood samples were collected from healthy cats in Harbin, revealing an overall FBoV prevalence of 12.1%. Notably, genotypes 1 and 3 of FBoV were found co-circulating among the cat population in Harbin. Additionally, recombination events were detected, particularly in the newly discovered NG/104 and DL/102 strains. Furthermore, negative selection sites were predominantly observed across the protein coding genes of FBoV. These findings suggest a co-circulation of genetically diverse FBoV strains among cats in Harbin, indicate that purifying selection is the primary driving force shaping the genomic evolution of FBoV, and also underscore the importance of comprehensive surveillance efforts to enhance our understanding of the epidemiology and evolutionary characteristics of FBoV.

Epidemiology and genetic diversity of bocavirus in wild rodents in urban areas of Guangzhou, Southern China

Members of the genus Bocaparvovirus have a significant impact on human health and can infect a wide range of hosts, increasing the likelihood of crossing species barriers. Among the various mammalian hosts, rodents are widely recognized as important reservoirs for emerging and zoonotic viruses. However, despite recent reports of bocavirus infections in rodents, our current understanding of rat bocavirus (RBoV) genetic diversity and evolution is limited. In this study, rodent samples were collected from the urban areas of Guangzhou city, Southern China, to investigate the presence and genetic diversity of RBoV. Through PCR-based screening of 296 rodent spleens, 54 samples were determined to be positive for RBoV infection, and 12 nearly complete genome sequences of RBoV were recovered. Phylogenetic analysis revealed distinct lineages and sub-lineages of RBoV, and six recombination events with strong statistical support were identified, with five of these events involving sequences obtained from this study. These results highlight the genetic diversity of RBoV circulating in rodents in Guangzhou city and emphasize the importance of extensive surveillance to gain a better understanding of RBoV epidemiology, evolutionary characteristics, and potential for cross-species transmission.

Simultaneous identification of DNA and RNA pathogens using metagenomic sequencing in cases of severe acute respiratory infection

Metagenomic next-generation sequencing (mNGS) is a valuable technique for identifying pathogens. However, conventional mNGS requires the separate processing of DNA and RNA genomes, which can be resource- and time-intensive. To mitigate these impediments, we propose a novel method called DNA/RNA cosequencing that aims to enhance the efficiency of pathogen detection. DNA/RNA cosequencing uses reverse transcription of total nucleic acids extracted from samples by using random primers, without removing DNA, and then employs mNGS. We applied this method to 85 cases of severe acute respiratory infections (SARI). Influenza virus was identified in 13 cases (H1N1: seven cases, H3N2: three cases, unclassified influenza type: three cases) and was not detected in the remaining 72 samples. Bacteria were present in all samples. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii were detected in four influenza-positive samples, suggesting coinfections. The sensitivity and specificity for detecting influenza A virus were 73.33% and 95.92%, respectively. A κ value of 0.726 indicated a high level of concordance between the results of DNA/RNA cosequencing and SARI influenza virus monitoring. DNA/RNA cosequencing enhanced the efficiency of pathogen detection, providing a novel capability to strengthen surveillance and thereby prevent and control infectious disease outbreaks.

Phylogenetic Analysis and Codon Usage Bias Reveal the Base of Feline and Canine Chaphamaparvovirus for Cross-Species Transmission

Chaphamaparvoviruses (ChPVs) are ancient viruses that have been detected in a variety of hosts. In this study, through a phylogenetic analysis and the adaptability of ChPV to multiple hosts, we evaluated the basis for the ability of feline (FeChPV) and canine ChPV (CaChPV) for cross-species transmission. Phylogenetic analysis showed that FeChPV and CaChPV were closely related. Notably, two strains of ChPVs isolated from domestic cats and two from dogs clustered together with CaChPVs and FeChPVs, respectively, suggesting that the stringent boundaries between canine and feline ChPV may be broken. Further analysis revealed that CaChPV and FeChPV were more adapted to dogs than to cats. Mutation analysis identified several shared mutations in cross-species-transmissible strains. Furthermore, the VP structures of FeChPV and CaChPV exhibited a high degree of similarity across both cross-species-transmissible and non-cross-species-transmissible strains. However, it is crucial to note that these results are largely computational, and limitations exist in terms of the number and diversity of samples analyzed; the capacity for cross-species transmission should be approached with caution and elucidated in further studies.

Virome Profiling of an Amur leopard cat Reveals Multiple Anelloviruses and a Bocaparvovirus

As a small top predator, Amur leopard cat (Prionailurus bengalensis euptilurus) is widely distributed in northeast Asia and plays an important role in the control of small rodent populations and in the maintenance of ecological equilibrium. However, the viruses harbored by this creature have been rarely investigated. Here, we report the DNA and RNA eukaryotic virome profiling of an injured Amur leopard cat followed by PCR validation, which revealed diverse anelloviruses in multiple organs and a bocaparvovirus in the lymph, but no RNA viruses. These anelloviruses have diverse genomic structures and are classified into four phylogroups with viruses of various felines, while the bocaparvovirus is extremely similar to those recovered from diarrheal domestic cats, illustrating the transmission of the virus between domestic animals and wildlife. These data provide the first insight into the genetic diversity of Amur leopard cat viruses, highlighting the need for further investigation of wild animals.

Epidemiology and Evolution of Emerging Porcine Circovirus-like Viruses in Pigs with Hemorrhagic Dysentery and Diarrhea Symptoms in Central China from 2018 to 2021

Porcine circovirus-like virus (PCLV) is a type of circular Rep-encoding single-stranded DNA virus and may be associated with the development of diarrheal symptoms in pigs. In this study, we retrospectively analyzed three years of past cases in Anhui, China, and reported a case of hemorrhagic enteritis and death in a pregnant sow possibly caused by PCLV. In addition, we analyzed the evolutionary characteristics of PCLV and found that mutation, recombination and selective pressure all played an important role in the evolution of PCLV. We identified N15D and T17S as well as L56T, T58R, K59Q, M62R, L75I and R190K mutations in two different branches, and we noted recombination events in the Rep of a group of Chinese strains. Analysis of selection pressure revealed that PCLV gained more positive selection, indicating that the virus is in a continuous evolutionary state. The PR2 plot, ENC-plot and neutrality analysis showed a greater role of natural selection than that of mutational pressure in the formation of codon usage patterns. This study is the first to identify PCLV in sows with hemorrhagic dysentery and death, and it provides new epidemiological information on PCLV infection in pigs in China.