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Influenza D virus (IDV) utilizes bovines as a primary reservoir with periodical spillover to other hosts. We have previously demonstrated that IDV binds both 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac2) and 9-O-acetylated N-glycolylneuraminic acid (Neu5Gc9Ac). Bovines produce both Neu5,9Ac2 and Neu5Gc9Ac, while humans are genetically unable to synthesize Neu5Gc9Ac. 9-O-Acetylation of sialic acids is catalyzed by CASD1 via a covalent acetyl-enzyme intermediate. To characterize the role of Neu5,9Ac2 and Neu5Gc9Ac in IDV infection and determine which form of 9-O-acetylated sialic acids drives IDV entry, we took advantage of a CASD1 knockout (KO) MDCK cell line and carried out feeding experiments using synthetic 9-O-acetyl sialic acids in combination with the single-round and multi-round IDV infection assays. The data from our studies show that (i) CASD1 KO cells are resistant to IDV infection and lack of IDV binding to the cell surface is responsible for the failure of IDV replication; (ii) feeding CASD1 KO cells with Neu5,9Ac2 or Neu5Gc9Ac resulted in a dose-dependent rescue of IDV infectivity; and (iii) diverse IDVs replicated robustly in CASD1 KO cells fed with either Neu5,9Ac2 or Neu5Gc9Ac at a level similar to that in wild-type cells with a functional CASD1. These data demonstrate that IDV can utilize Neu5,9Ac2- or non-human Neu5Gc9Ac-containing glycan receptor for infection. Our findings provide evidence that IDV has acquired the ability to infect and transmit among agricultural animals that are enriched in Neu5Gc9Ac, in addition to posing a zoonotic risk to humans expressing only Neu5,9Ac2.IMPORTANCEInfluenza D virus (IDV) has emerged as a multiple-species-infecting pathogen with bovines as a primary reservoir. Little is known about the functional receptor that drives IDV entry and promotes its cross-species spillover potential among different hosts. Here, we demonstrated that IDV binds exclusively to 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac2) and non-human 9-O-acetylated N-glycolylneuraminic acid (Neu5Gc9Ac) and utilizes both for entry and infection. This ability in effective engagement of both 9-O-acetylated sialic acids as functional receptors for infection provides an evolutionary advantage to IDV for expanding its host range. This finding also indicates that IDV has the potential to emerge in humans because Neu5,9Ac2 is ubiquitously expressed in human tissues, including lung. Thus, results of our study highlight a need for continued surveillance of IDV in humans, as well as for further investigation of its biology and cross-species transmission mechanism.

The Streptococcus suis (S. suis) is an important zoonotic pathogen that causes streptococcal disease in pigs and poses a threat to humans. This study provides an understanding of the prevalence of S.suis in eastern China and provides guidance for clinical prophylaxis. From 2021 to 2023, a total of 143 strains of S. suis were isolated from 1642 lung tissue and nasal swabs from healthy and suspected infected pigs in Shandong Province, China, using the Phenotypic tests and PCR technique. The isolates were then tested for serotype, virulence-related genes, and resistance genes. Among the 143 isolates, type 2 was the predominant serotype with 98 isolates (98/143, 68.5%), followed by type 5 with 22 isolates (22/143, 15.3%), type 4 with 6 isolates (6/143, 4.2%), type 19 with 4 isolates (4/143, 2.8%) and type 21 with 5 isolates (5/143, 3.5%), respectively. A minimum of 78.3% of the strains exhibited the presence of virulence-related genes including pgda, dlta, mann, fbps, orf2, and sspa, whereas the virulence-associated genes Sum, Sly, and Salkr are not widely prevalent. For the detection of resistance genes, it was found that the tetO gene had a high detection rate of 70.1% (101/143), whereas neither the pbp2b gene nor the cat1 and cat2 genes were detected. Antimicrobial susceptibility testing revealed that 96.5% (138/143) of the isolates exhibited multidrug resistance (MDR). And polypeptide B was found to be tolerated by 125 of the 143 strains (87.4%). Although we did not detect the β-lactam resistance gene in any of the 143 strains, an average of 39.2% of the strains were resistant to β-lactam antibiotics. The results of the current study is thought it may be help to understand the prevalence of S. suis and provide important insights into treatment and prevention. [ABSTRACT FROM AUTHOR]

Influenza D virus (IDV) is a newly emerged zoonotic virus increasingly reported worldwide. Cattle are considered the main reservoir of IDV, although it was first isolated from pigs. IDV infects multiple animal species and contributes to the bovine respiratory disease complex (BRDC). To date, there has been no report on the presence and frequency of IDV among cattle herds in Pakistan. In this study, we collected nasal swabs from cattle and performed virological surveillance of IDV via qRT-PCR. Among 376 swab samples, IDV was detected in 9 samples (2.4%). Four dairy cattle farms were positive for IDV; two IDV-positive samples (two/nine, 22.2%) belonged to asymptomatic cattle, while seven IDV-positive samples (seven/nine, 77.8%) were from cattle showing respiratory clinical signs, including two with a recent history of abortion and mastitis. Partial sequences of the hemagglutinin–esterase-fusion gene of IDV were obtained from nine qRT-PCR-positive samples. Notably, all IDV strains in this study clustered within the D/OK lineages in phylogenetic analysis. A 98.8–99.6% genetic identity to its European and US counterparts indicates that the IDVs are closely related. The D/OK lineage of IDV was previously unreported in Pakistan. This is the first report of IDV in Pakistan. We confirmed that IDV is circulating among cattle herds in Pakistan. This study underscores the importance of virological surveillance to monitor the ecology of IDV for better animal and public health. The continued spread of IDV and its adaptation to various hosts necessitate further epidemiological studies. [ABSTRACT FROM AUTHOR]

Pangolins have been found to carry severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)‐related coronaviruses. In light of this discovery, interest has been piqued in viromes of these heavily trafficked wild animals. In this study, we performed viral metagenomic sequencing to explore viromes of both confiscated dead pangolins and captive healthy pangolins. Sequence reads of vertebrate‐associated viruses in Herpesviridae, Retroviridae, Iridoviridae, Reoviridae, Arenaviridae, and Flaviviridae were detected in confiscated dead pangolins. A novel rotavirus (RV) (Reoviridae), showing a high degree of genetic similarity to the RV species D (RVD) that was previously unreported in mammals, was further confirmed by using reverse transcription‐polymerase chain reaction (RT‐PCR) and Sanger sequencing. Three out of 18 samples from the confiscated dead pangolins were positive for genomic sequences of the novel RV. Importantly, sequence alignments and phylogenetic analyses demonstrated that these RV strains genetically belonged to the RVD. Nevertheless, these novel RVD strains were divergent from known RVD strains that have been found only in Avian. They formed a separate genetic cluster. Five serial passages were attempted to isolate the RV, but no live virus was obtained. In addition, fecal samples were collected from healthy pangolins (n = 41) in our institution and screened for RVs by viral metagenomic sequencing and RT‐PCR. In these fecal samples, neither species D nor previously identified species A RVs were detected. This study reported RVDs in pangolin samples for the first time to our knowledge. Identifiability disagreements between wild and captive pangolins highlight the need for further exploration into pangolin viruses to better understand their emergence and transmission potential. [ABSTRACT FROM AUTHOR]

Highly pathogenic avian influenza viruses (HPAIVs) of the H5N1 subtype (clade 2.3.4.4b) have been detected in raw milk from infected cows. Several studies have examined the time and temperature parameters to ascertain whether influenza viruses in milk can be inactivated completely under commercial pasteurization conditions, yielding conflicting results. This study aimed to investigate whether milk could help protect influenza viruses from heat treatment. After heat treatment at 49 °C for one hour, the titer reduction of the influenza A/WSN/1933 (A/H1) virus in milk was approximately 1.6 log10TCID50/mL, which was significantly lower than that (3 log10TCID50/mL) observed in the Dulbecco's Modified Eagle Medium (DMEM) control media. The influenza D/bovine/CHN/JY3002/2022 (D/Yama2019) virus in milk retained a high residual infectivity (4.68 × 103 log10TCID50/mL) after treatment at 53 °C; however, the virus in DMEM completely lost its infectivity under the same conditions. Moreover, the influenza A/chicken/CHN/Cangzhou03/2023 (A/H5) virus in DMEM could be inactivated completely using any of the three heat treatment methods: 63 °C for 30 min, 72 °C for 15 s, or 80 °C for 15 s. For the virus present in milk, only heat treatment at 80 °C for 15 s completely inactivated it. These results suggest that milk prevents influenza viruses from pasteurization inactivation. [ABSTRACT FROM AUTHOR]