Isolation and characterization of a novel parvovirus from a red-crowned crane, China, 2021.

BACKGROUND: Parvoviruses are icosahedral, nonenveloped viruses with single-stranded DNA genomes of approximately 5 kb in length. In recent years, parvoviruses have frequently mutated and expanded their host range to cause disease in many wild animals by altering their tissue tropism. Animal infection mainly results in acute enteritis and inflammation of other organs. In this study, we used a viral metagenomic method to detect a novel parvovirus species in a red-crowned crane that died due to severe diarrhea in China. RESULTS: The presence of the viral genome in the kidney, lung, heart, liver, and intestine were confirmed by PCR. Histopathological examination of the intestine showed a large number of infiltrated inflammatory cells. The JL21/10 strain of the red-crowned crane parvovirus was first isolated from the intestine. Whole-genome sequence analysis showed that JL21/10 shared high identity with the red-crowned crane Parvovirinae strains yc-8 at the nucleotide level (96.61%). Phylogenetic analysis of the complete genome and NS1 gene revealed that the JL21/10 strain clustered with strains in chicken and revealed a close genetic relationship with the red-crowned crane parvovirus strains.The complete of VP2 gene analysis showed that JL21/10 shared identity with the red-crowned crane yc-8 strains (97.7%), chicken (55.4%),ducks(31.0%) and geese(30.1%) at the amino acid level. The result showed that red-crowned crane parvovirus may be cross-species transmission to chicken. However, There is little possibility of transmission to ducks and geese. CONCLUSION: This is the first isolation and identification of a parvovirus in red-crowned crane that was associated with severe diarrhea.

Rabies viruses in specific wild fur animals in northern China, 2017-2019.

In recent years, rabies virus (RABV) has been detected in numerous specific wild fur animals in northern China. Therefore, we performed an epidemiologic investigation of RABV in the main fur animal farming provinces during 2017-2019. The results showed that brain tissue samples from eight animals that presented with central nervous symptoms were positive for rabies virus according to direct fluorescent antibody assays and RT-PCR. The phylogenetic relationships and distributions of the viruses were determined, and the results indicated that they belonged to Cosmopolitan and Arctic-related lineages. Serological investigations revealed a RABV positivity rate of 2.78% (34/1,222) in fur animals. A total of 79 unimmunized breeders were negative for serum antibodies, and 9.62% of 52 immunized breeders (5/52) were not seroconverted. The results emphasize that specific wild fur animals are potential sources of RABV and that the current vaccination programme for animals and breeders is deficient, indicating the need for mandatory rabies vaccination to eliminate rabies transmission from dogs to farmed fur animals.

Molecular evidence of the spotted fever group Rickettsiae in ticks from Yunnan Province, Southwest China.

Ixodid ticks transmit many obligate intracellular Rickettsial species. Several previous studies have identified Rickettsia species in the northeastern and southern part of China, but few reports on the prevalence of infection of spotted fever group Rickettsiae (SFGR) in ticks in southwest China are available. Here, we investigated SFGR in 394 adult ticks of five species including Dermacentor nuttalli, Dermacentor silvarum, Haemaphysalis longicornis, Ixodes sinensis and Ixodes persulcatus, collected in the border region between China and Burma in Yunnan Province. PCR was used to detect the presence of the citrate synthase (gltA) gene of Rickettsia species. SFGR was found in 12.1% (15/124) of I. persulcatus ticks, which was significantly higher than the 7.2% (7/97) positive D. nuttalli, 5.4% (3/56) D. silvarum, 5.6% (4/72) H. longicornis and 4.4 (2/45) I. sinensis. A portion of the gltA and ompA gene data subjected to phylogenetic analysis revealed that the detected SFGR clustered into two species, Rickettsia raoultii and the new Rickettsia species Candidatus Rickettsia jingxinensis. Detection of both Rickettsia spp. in this region indicates a potential public health threat posed by SFGR infection in Yunnan Province.

A Tentative Tamdy Orthonairovirus Related to Febrile Illness in Northwestern China.

BACKGROUND: Many novel tick-borne viruses have been discovered by deep-sequencing technology in recent years; however, their medical significance is unknown. METHODS: We obtained clinical data of a patient from Xinjiang, China. Possible pathogens were detected by metagenomic analysis; the causative pathogen Tacheng tick virus 1 (TcTV-1) was found and further confirmed by reverse transcriptase-polymerase chain reaction, viral culture, and sequence analyses. Epidemiological investigation was conducted in the local human population, domestic animals, and ticks by serological/molecular methods. RESULTS: A 62-year-old woman with a history of tick bite in Qinghe, Xinjiang, presented with fever and rashes. These symptoms were relieved after clinical treatment. TcTV-1 (strain QH1) was isolated from the patient's cerebrospinal fluid, throat swabs, and urine on day 47 after illness onset. Although the blood and urine showed viral RNA positive on day 73 after illness onset, the virus was only isolated from urine. Serological detection revealed a virus neutralizing antibody titer of 1:40 and 1:80 on day 47 and 73 after illness onset, respectively. No coinfection with other pathogens was detected, suggesting TcTV-1 may be the potential causative pathogen. We detected anti-TcTV-1 antibodies (immunoglobulin G: 10.1%; immunoglobulin M: 4.8%) in the local human population. The viral RNA was also found in cattle (4.9%), sheep (9.2%), and ticks, including Dermacentor marginatus (14.3%), Dermacentor silvarum (11.8%), Dermacentor nuttalli (6.7%), and Hyalomma asiaticum (4.8%). CONCLUSIONS: TcTV-1 may be associated with a febrile illness syndrome, and epidemiological data of the virus in humans and animals necessitate disease surveillance of TcTV-1 infection in China.

First isolation and characterization of Getah virus from cattle in northeastern China.

BACKGROUND: Getah virus (GETV) is a neglected mosquito-borne Alphavirus that causes pyrexia, body rash, and leg oedema in horses and foetal death and reproductive disorders in pigs. Infected animals may play a critical role in the amplification and circulation of the virus. The present study aimed to investigate GETV infection in clinically infected cattle and vector mosquito species in northeastern China. RESULTS: Serum samples were collected from beef cattle that presented sudden onset of fever in forest grazing areas, and metagenomic sequencing was conducted, revealing 29 contigs from ten serum samples matching the GETV genome. Quantitative RT-PCR (RT-qPCR) was performed with GETV RNA from 48 beef cattle serum samples, showing that the overall prevalence of GETV in the beef cattle samples was 6.25% (3/48). Serological investigation indicated that GETV neutralizing antibodies were detected in 83.3% (40/48, 95% CI 67-100) of samples from the study region. The GETV JL1808 strain was isolated from clinically infected cattle showing fever. Sequence comparisons showed high identity with the HuN1 strain, a highly pathogenic swine epidemic isolate obtained in Hunan province in 2017, at the nucleotide level (99.5%) and at the deduced amino acid level (99.7-99.9%). The phylogenetic analysis of JL1808 clustered in Group III, and also revealed a close genetic relationship with the HuN1 strain. Additionally, about 12,000 mosquitoes were trapped in this region. The presence of GETV infection was detected in mosquitoes, suggesting that the minimum infection rate (MIR) was 1.50‰, with MIRs of 1.67‰ in Culex pseudovishnui, 1.60‰ in Culex tritaeniorhynchus, and 1.21‰ in Anopheles sinensis. CONCLUSIONS: To the best of our knowledge, this is the first report of GETV infection in cattle. These results demonstrated that a highly pathogenic, mosquito-borne swine GETV can infect and circulate in cattle, implying that it is necessary to conduct surveillance of GETV infection in animals in northeastern China.

Improved duplex RT-PCR assay for differential diagnosis of mixed infection of duck hepatitis A virus type 1 and type 3 in ducklings.

Infection with duck hepatitis A virus (DHAV) causes an acute, rapidly spreading, and fatal disease of young ducklings. DHAV type 1 (DHAV-1) and type 3 (DHAV-3) have been identified in China. In this study, a duplex RT-PCR assay was developed to identify DHAV-1 and DHAV-3 with mixed infection. The method was shown to be high specificity and sensitivity. The minimum detection limit of the method has been determined to be 10pg total RNA templates extracted from duck liver samples or 10² copies viral RNA of DHAV-1 and DHAV-3 respectively. Using the method, from 60 clinical liver samples of 26 duckling flocks in Shandong, Guangdong, Sichuan and Henan provinces of China, 15 (57.7%) flocks were identified as mixed infection of DHAV-1 and DHAV-3, and 9 (34.6%) flocks were DHAV-1 or DHAV-3 single infection. Among them, 38.3% (23/60) of duckling samples were detected as mixed infection of DHAV-1 and DHAV-3, and 48.3% (29/60) of samples were DHAV-1 or DHAV-3 single infection. These results indicated that the improved duplex RT-PCR method provides a rapid and cost-effective laboratory differential diagnosis for mixed infection of DHAV-1 and DHAV-3 in ducklings.

[Sequence analysis of VP1 gene of the duck hepatitis A virus type 3 strains isolated from Shandong Province of China in 2012].

To reveal the genetic variation of the viral protein 1 (VP1) gene of the duck hepatitis A virus type 3 (DHAV-3), the VP1 gene of 13 virulent DHAV-3 strains isolated from Shandong province of China in 2012 were amplified by RT-PCR, sequenced and analyzed. The results showed that all the VP1 genes of the 13 isolates contained 720 nucleotides encoding 240 amino acids, and shared with nucleotide identities of 94. 6%-99.9% and amino acid identities of 95.0%-100%. The nucleotide and amino acid sequence homologies between the 13 DHAV-3 isolates and other 31 DHAV-3 reference strains were 92.5%-100% and 90. 8%-100%, respectively. Phylogenetic analysis showed that the VP1 gene of DHAV-3 had distinct geographical characteristics. Distribution of genotypes of the 44 DHAV-3 strains was as follows: except the vaccine strain B63, all the other Chinese isolates belonged to genotype I (GI), Vietnamese wild isolates mainly belonged to subtype 1 (S1) of genotype II (GII), and all Korean isolates belonged to subtype 2 (S2) of GII.

Genetic variation of the VP1 gene of the virulent duck hepatitis A virus type 1 (DHAV-1) isolates in Shandong province of China.

To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1 (DHAV-1) isolates, the virulence, cross neutralization assays and the complete sequence of the virion protein 1 (VP1) gene of nine virulent DHAV-1 strains, which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008, were tested. The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses (ELD(50)s) and the median lethal doses (LD(50)s), respectively. The results showed that the ELD(50)s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10(6)/mL to 1.44 × 10(7)/mL, while the LD(50)s were 2.39 × 10(5)/mL to 6.15 × 10(6)/mL. Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates, respectively. Compared with other virulent, moderate virulent, attenuated vaccine and mild strains, the VP1 genes of the 9 strains shared 89.8%-99.7% similarity at the nucleotide level and 92.4%-99.6% at amino acid level with other DHAV-1 strains. There were three hypervariable regions at the C-terminus (aa 158-160, 180-193 and 205-219) and other variable points in VP1 protein, but which didn't cause virulence of DHAV-1 change.