Rabbit astrovirus (RAstV) is a pathogen that causes diarrhea in rabbits, with high infection rate at various stages, which can often cause secondary or mixed infections with other pathogens, bringing great economic losses to the rabbit industry. In this study, 10 samples were collected from cases of rabbits with diarrhea on a rabbit meat farm in the Shandong area of China. The positive sample for astrovirus detected by RT-PCR was inoculated into an RK 13 cell line. A rabbit astrovirus strain named Z317 was successfully isolated, which produced an obvious cytopathic effect 48 h post-inoculation in the RK 13 cell line. The genome structure of this isolate was studied by high-throughput sequencing, showing that the Z317 strain had the highest similarity with the American strain TN/2208/2010, with 92.43% nucleotide homology, belonging to group MRAstV-23. The basic properties of the Z317 capsid (Cap) protein were analyzed, and 10 liner B cell epitopes were screened with the online biosoft Bepipred 2.0 and SVMTriP, including 445–464, 186–205, 655–674, 88–107, 792–811, 45–64, and 257–276 amino acids. This is the first contribution concerning RAstV genomes in China; more studies are needed to understand the diversity and impact of RAstV on rabbit health.

Acholeplasma laidlawii is a Mycoplasma species widely distributed in the environment. It is often regarded as an opportunistic pathogen capable of causing respiratory infections in animals and humans. To date, only a few studies have reported A. laidlawii infection in poultry. In the present study, an A. laidlawii strain was isolated from the lungs and trachea of diseased ducks presenting with air sac lesions. Antimicrobial susceptibility testing revealed that the isolate was susceptible to tylvalosin, tylosin, and valnemulin, with relatively low minimum inhibitory concentrations (MICs). The pathogenicity of the isolate was evaluated using specific-pathogen-free (SPF) ducks via subcutaneous inoculation. No clinical signs were observed during the experimental period. Oral and cloacal swabs, as well as tissue samples, were tested by PCR. The results showed that the pathogen was detectable in swabs from 5 to 21 days post-inoculation (dpi), and all lung and tracheal samples from infected ducks tested positive. Histopathological examination of the lungs and trachea revealed pathological changes in both tissues. Collectively, these findings demonstrated that A. laidlawii was capable of colonizing ducks and inducing mild histopathological changes, suggesting that this pathogen might pose an epidemiological risk in duck farming. Furthermore, these results indicate that A. laidlawii could colonize ducks, underscoring the need for continued surveillance to monitor for emerging pathogens in ducks.

A rabbit rotavirus Z3171 isolate from diarrheic rabbits was identified and sequenced. The genotype constellation of Z3171 was as follows: G3; P[22]; I2; R3; C3; M3; A9; N2; T1; E3; H3,which is different from the constellation observed in previously characterized LRV strains. However, the genome of Z3171 differed substantially from that of the other rabbit rotavirus strains, N5 and Rab1404, in terms of both gene content and gene sequence. Our study shows a reassortment event between human and rabbit rotavirus strains, or there may be undetermined gene clusters circulating in the rabbit population. Further, we report the detection of G3P[22] RVA strain in rabbits from China for the first time.

Children and multiple species of domestic animals are susceptible to infection of group A rotaviruses (RVAs) that causes acute gastroenteritis. We isolated an RVA (Z3171) from diarrheic rabbits and characterized its whole-length genome and pathogenicity in rabbits. The genotype constellation of Z3171 was as follows: G3; P[22]; I2; R3; C3; M3; A9; N2; T1; E3; H3,which is different from the constellation observed in previously characterized LRV strains. The result showed that the NSP3 gene of Z3171 belonged to the T1 genotype and shared 96.2% nucleotide identities with other T1 human strain LL4260 circulating in the regions. However the genome of Z3171 differed substantially from that of the other rabbit rotavirus strains, N5 and Rab1404, in terms of both gene content and gene sequence, particularly the NSP5 gene. Our study shows a reassortment event between human and rabbit rotavirus strains, or there may be undetermined gene clusters circulating in the rabbit population. The isolated strain can cause diarrhea in Belgian rabbits in animal regression test. The infection rate was 100%, and the incidence rate was 80%. Further, we report the detection of G3P[22] RVA strain in rabbits from China for the first time.

Pasteurella multocida is a zoonotic pathogen that causes severe respiratory infections in domestic rabbits. Serogroup F strains have been increasingly reported but remain poorly characterized. Two strains, PS-JQ08 (serogroup A) and PS-JQ09 (serogroup F), were isolated from deceased rabbits in China. Pathogenicity was assessed in mouse and rabbit models, and whole-genome sequencing was performed for comparative genomic analysis. Both strains were highly pathogenic but induced distinct pathological profiles: PS-JQ08 caused hepatocellular vacuolar degeneration, whereas PS-JQ09 induced hemorrhage and edema. Genomic analysis revealed that both strains harbored core virulence genes involved in adhesion, iron acquisition, and antiphagocytosis; however, the serogroup F strain harbored unique iron transport genes and arsenic resistance systems. Phylogenetic analysis revealed that PS-JQ08 clustered with avian serogroup A strains, whereas PS-JQ09 clustered with porcine- and rabbit-derived serogroup F strains. These findings provide clues for exploring the genetic mechanism underlying pathogenic differentiation of Pasteurella multocida between serogroups A and F, and provide valuable genomic information to support vaccine development and disease control in rabbits.