The naked mole-rat (NMR, Heterocephalus glaber) is being bred as a novel laboratory animal due to its unique biological characteristics, including longevity, cancer resistance, hypoxia tolerance, and pain insensitivity. It is expected that differences exist between the microbiota of wild NMRs and that of NMRs in an artificial environment. Overall, the effect of environment on changes in the NMR microbiota remains unknown. In an attempt to understand the microbiota composition of NMRs in captivity, variability in the microbiota of the intestinal and respiratory tracts of two groups of NMRs was assessed under two conditions. The results obtained by high-throughput sequencing revealed significant differences at the phylum, class, order, family and genus levels in the microbiota between the two groups of NMRs examined (first group in conventional environment, second group in barrier environment). For the trachea, 24 phyla and 533 genera and 26 phyla and 733 genera were identified for the first and second groups of animals. Regarding the cecum, 23 phyla and 385 genera and 25 phyla and 110 genera were identified in the microbiota of first and second groups of animals. There were no obvious differences between females and males or young and adult animals. Our results suggest that the intestinal and respiratory tract NMR microbiota changed during captivity, which may be related to the transition to the breeding environment. Such changes in the microbiota of NMRs may have an effect on the original characteristics, which may be the direction of further research studies.

Background: Pigeon circovirus infections in pigeons (Columba livia domestica) have been reported worldwide. Pigeons should be PiCV-free when utilized as qualified experimental animals. However, pigeons can be freely purchased as experimental animals without any clear guidelines to follow. Herein, we investigated the status quo of PiCV infections on a pigeon farm in Beijing, China, which provides pigeons for experimental use. Results: PiCV infection was verified in at least three types of tissues in all forty pigeons tested. A total of 29 full-length genomes were obtained and deposited in GenBank. The whole genome sequence comparison among the 29 identified PiCV strains revealed nucleotide homologies of 85.8–100%, and these sequences exhibited nucleotide homologies of 82.7–98.9% as compared with those of the reference sequences. The cap gene displayed genetic diversity, with a wide range of amino acid homologies ranging from 64.5% to 100%. Phylogenetic analysis of the 29 full-genome sequences revealed that the PiCV strains in this study could be further divided into four clades: A (17.2%), B (10.4%), C (37.9%) and D (34.5%). Thirteen recombination events were also detected in 18 out of the 29 PiCV genomes obtained in this study. Phylogenetic research using the rep and cap genes verified the recombination events, which occurred between clades A/F, A/B, C/D, and B/D among the 18 PiCV strains studied. Conclusions: In conclusion, PiCV infection, which is highly genetically varied, is extremely widespread on pigeon farms in Beijing. These findings indicate that if pigeons are to be used as experimental animals, it is necessary to evaluate the impact of PiCV infection on the results.

Intensive efforts have been made to develop models of hRSV infection or disease using various animals. However, the limitations such as semi-permissiveness and short duration of infection have impeded their applications in both the pathogenesis of hRSV and therapeutics development. Here, we present a mouse model based on a Rag2 gene knockout using CRISPR/Cas9 technology. Rag2^−/− mice sustained high viral loads upon intranasal inoculation with hRSV. The average peak titer rapidly reached 1 × 10^9.8 copies/g and 1c10⁶ TCID₅₀ in nasal cavity, as well as 1 × 10⁸ copies/g and 1 × 10⁵ TCID₅₀ in the lungs up to 5 weeks. Mild interstitial pneumonia, severe bronchopneumonia, elevated cytokines and NK cells were seen in Rag2^−/− mice. A humanized monoclonal antibody showed strong antiviral activity in this animal model, implying that Rag2^−/− mice that support long-term stable infection are a useful tool for studying the transmission and pathogenesis of human RSV, as well as evaluating therapeutics.

Hepatitis E virus (HEV) is zoonotic and the leading cause of acute viral hepatitis worldwide. Rabbit HEV can infect humans and is prevalent globally. It is reported that laboratory rabbits are also naturally infected with HEV. Therefore, it is important to investigate in a large scale the prevalence of HEV in laboratory rabbits. Serum samples were collected from 649 laboratory rabbits of 13 different commercial vendors in Beijing, China, from 2017 to 2019, and anti-HEV and HEV antigen (Ag) were tested. Fecal samples were collected from 50 laboratory rabbits from one of the vendors for HEV RNA detection. Six laboratory rabbits with natural HEV infection were euthanized and their liver, kidney, bile and urine samples were collected for HEV RNA quantification. Liver tissues were subjected to histopathology analysis. The overall positive rates of anti-HEV antibodies and HEV-Ag are 2.6% (15/588) and 7.9% (51/649), respectively. HEV RNA was detected in 12.0% (6/50) of the rabbits. High viral load of HEV RNA was detected in liver and bile samples. Liver inflammation was observed. HEV is circulating in laboratory rabbit population in China. Strict screening is crucial to ensure experimental accuracy and prevent zoonotic transmission to research personnel.

The emergence of coinfection with Toxoplasma gondii, Neospora caninum, Eimeria stiedai, Giardia lamblia, and Trypanosoma evansi is an important problem that endangers human health, animal quality and public sanitary security. These pathogenic protozoans play important roles in establishment of similar clinical signs of diseases in humans, pigs, sheep, and rabbits, including fever, diarrhea, hepatitis, encephalitis, and reproductive disorders. Therefore, a rapid and specific diagnostic method to simultaneously detect these five pathogens is urgently required. Here, we developed a TaqMan-probe-based quantitative real-time polymerase chain reaction (qPCR) for the simultaneous detection of these five pathogens for the first time. Specific primers and probes were designed targeting the G3PDH gene of Toxoplasma gondii, the NC5 gene of Neospora caninum, the ADF gene of Eimeria stiedai, the GDH gene of Giardia lamblia, the COX1 gene of Trypanosoma evansi, and a TaqMan-probe-based pentaplex qPCR assay capable of simultaneously detecting these five pathogens was developed. The assay showed strong specificity, with no cross-reactivity detected against nucleic acids from other control pathogens. The assay demonstrated high sensitivity, with the lower limit of quantification (LLOQ) of 10 copies per reaction for the recombinant plasmid standards pTgG3PDH, pNcNC5, pEsADF, pGlGDH, pTeCOX1, and the limit of detection (LOD) as low as 1.1 copies. The standard curves exhibited excellent linearity (correlation coefficient values of 0.996, 0.996, 0.996, 0.992, and 0.996, respectively) and high amplification efficiencies (95.534%, 96.203%, 107.818%, 100.851%, and 104.487%, respectively). The assay also exhibited excellent repeatability and reproducibility, with inter- and intra-assay coefficient of variation (CV) ranging from 0.07% to 2.13%. The anti-interference test showed that high-concentration nucleic acids did not interfere with low-concentration nucleic acids, thus ensuring excellent detection results even in complex samples. Among 210 clinical samples, the assay detected Toxoplasma gondii in 2.38%, Neospora caninum in 2.38%, Eimeria stiedai in 10%, and Giardia lamblia in 36.19%. The coinfection rates were 8.1% for Eimeria stiedai & Giardia lamblia. This TaqMan-probe-based pentaplex qPCR assay offers a rapid, sensitive, and specific tool for the simultaneous detection of Toxoplasma gondii, Neospora caninum, Eimeria stiedai, Giardia lamblia, and Trypanosoma. It is of great significance to safeguard human health.

Pre-exposure prophylaxis of HIV infection with a microbicide is one of the most effective ways to block HIV/AIDS transmission. In this study, a potent and long-acting HIV entry inhibitor peptide 2P23 was developed as a novel HIV microbicide, and its toxicity and safety were evaluated through animal model in vivo for the first time, which provided a new effective means for the prevention of HIV/AIDS. In order to evaluate the potential effect to cause human toxicity and possible health hazards likely to arise from repeated rectovaginal application of 2P23, we conducted an acute toxicity in which a dose of 300 mg/kg of 2P23 was administrated by rectovaginal three times within 24-hour in male and female Sprague Dawley rats. Furthermore, a 90-day repeated rectovaginal treatment tests in rats were used to evaluate the chronic and reproductive toxicity of 50, 100, 200 mg/kg of 2P23. The effects of 2P23 administration on morbidity, mortality, clinical signs, changes in body weight, food consumption, clinical pathology, organ weight, hematological and physiological biochemical parameter indicators, histopathology, changes in rectovaginal microbiota, fertility, and early embryonic development were assessed. There were no mortality or abnormal clinical signs, no significant changes in body weight gain or hematological and physiological biochemical parameter indicators, no changes in necropsy and histopathology findings of vital organs, and no significant changes in rectum and vagina microbiota associated with the administration of 2P23. There were no effects on fertility and early embryonic development in male and female rats. The results indicate that 2P23 does not cause significant adverse effects in the 90-day and suggest that the no observed adverse effect level is 300 mg. This study has important application value and good innovation for the development of anti-HIV agents for rectovaginal administration. The novel HIV microbicide is safe and effective for the prevention and control of HIV/AIDS sexually transmitted infections, which enriches people’s understanding of the novel HIV microbicide gel. The study has important application value and good innovation for the development of anti-HIV agents for rectovaginal administration.