Aichivirus D (AiV-D) is a newly emerging diarrhea-associated pathogen in cattle and sheep, and comprised two officially recognized genotypes (AiV-D1 and AiV-D2) and two potential novel genotypes (AiV-D3 and AiV-D4). This study aimed to establish a fluorescent RT-PCR assay for detecting AiV-D and to investigate its prevalence in yak diarrheic samples. A SYBR Green fluorescent RT-PCR assay was successfully established by targeting the conserved region of viral 3D genes, enabling detection of all known AiV-D genotypes. The established assay was specific for AiV-D, exhibiting no cross-reactivity with other common diarrhea-causing pathogens in ruminants, with coefficients of variation for reproducibility ranging from 0.23% to 2.16% and detection limits for the positive plasmids of AiV-D1 to AiV-D4 at 2.21, 4.78, 4.10, and 5.94 copies/μL, respectively. Of the 166 diarrheic samples collected from calf yaks across nine farms in Sichuan province, China, between May and August 2023, 22.3% (37/166) tested positive for AiV-D, suggesting its substantial prevalence within the sampled region. Furthermore, seven complete 3D gene sequences were cloned from positive samples, and subsequent phylogenetic analysis revealed distinct evolutionary patterns among these isolates. In conclusion, this newly established assay represents a reliable diagnostic tool for AiV-D detection, while our findings provide significant insights into the epidemiological distribution and evolutionary dynamics of AiV-D in the yak population.

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Bovine respiratory disease (BRD) significantly impacts the beef and dairy industries. The acute phase proteins procalcitonin (PCT) and haptoglobin (Hp) have been proposed as useful biomarkers for BRD. Here, we examined the time course of these two biomarkers in BRD-affected calves and their relationship to prognosis. Hp and PCT were elevated on the 1st day of examination (day 1). The PCT value on day 1 showed a positive correlation with the BRD score on day 7. Therefore, serum PCT concentration on day 1 may be used to predict whether symptoms are present on day 7. This study provides useful insights into the use of PCT and Hp in the diagnosis of BRD, particularly the use of PCT to determine prognosis.

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African pygmy hedgehog adenovirus 1 (AhAdV-1) was isolated from a hedgehog exhibiting respiratory symptoms in Japan. In this study, we evaluated the cellular tropism of AhAdV-1 using various mammalian cell lines and investigated its genetic stability during long-term serial passage in MDCK cells. AhAdV-1 exhibited high replication efficiency in MDCK, MDBK, CPK, and Vero cells but showed limited growth in BHK, HeLa, and HC11 cells. No replication was detected in RAW 264.7 and 3LL cells. Since MDCK cells demonstrated the highest viral production, serial passage was performed up to 110 passages. Whole-genome analysis revealed only four mutations, suggesting that AhAdV-1 is a genetically stable virus. These findings contribute to the understanding of the host range and evolutionary stability of AhAdV-1.

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Using serological tools for bat- and shrew-borne hantaviruses, we investigated the seroprevalence of these viruses in 336 human sera from Sri Lanka, consisting of 168 healthy individuals and 168 febrile patients. Twelve and 31 sera were positive for Mix antigen-bat (recombinant N antigens of Brno, Dakrong, Quezon, Robina, and Xuan Son viruses) and Mix antigen-shrew (recombinant N antigens of Altai, Asama, Cao Bang, Nova, Seewis, and Thottapalayam viruses), respectively. 2 of 168 control sera and 39 of 168 febrile patient sera were positive for Mix antigen-bat or Mix antigen-shrew. Individual antigen reactions were positive for Quezon, Robina, Altai, Asama, Cao Bang, Seewis, and Thottapalayam viruses. These findings suggest that bat- and shrew-derived hantaviruses may infect humans in Sri Lanka.

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