One of the constraints to controlling foot‐and‐mouth disease (FMD) in East Africa is the incomplete knowledge of the specific FMD virus (FMDV) strains circulating and the way in which these viruses move across countries in the region. This retrospective study focuses on Ethiopia, which has one of the largest FMD‐susceptible livestock populations in Africa. Analyses of FMDV positive samples collected between 2008 and 2019 demonstrate that serotypes O (n = 175), A (n = 51) and SAT 2 (n = 33) were present in the country. Phylogenetic analysis of the VP1 sequences for these viruses showed that there were at least seven different FMD viral clades circulating during this period: O/EA‐3, O/EA‐4, A/AFRICA/G‐I, A/AFRICA/G‐IV, A/AFRICA/G‐VII, SAT2/VII and SAT2/XIII. Although these results only represent a snapshot and might not reflect all FMDV lineages that were present, they highlight the importance of serotype O, as well as the complexity and co‐existence of FMDV serotypes in Ethiopia and surrounding countries. These sequence data also support the idea that there are two FMDV ecosystems existing in East Africa. Data from retrospective studies, such as these presented here, will be beneficial for vaccine selection and vaccination campaigns to control FMDV within Ethiopia.

Laboratories working with foot-and-mouth disease virus (FMDV) must maintain a high level of biocontainment. However, if infectious virus is reliably inactivated during sample processing, molecular and serological testing can be performed at a lower level of containment. In this study, three commercial lysis buffers (AL, AVL, and MagMAX CORE) were tested in two laboratories for their ability to inactivate FMDV A/IRN/8/2015 in different sample matrices (cell culture supernatant, epithelial tissue suspension and milk). Residual infectivity after the addition of lysis buffer was evaluated by inoculating susceptible cell cultures. No cytopathic effect was observed for all three lysis buffers, indicating that the buffers are capable of reducing viral infectivity (estimated range 3.1 to >5.1 Log10). These results highlight the capacity of lysis buffers to decrease FMDV infectivity; however, additional validation experiments should be conducted, particularly if different sample matrices and/or lysis buffers are used.

The LFBK-α_vβ₆ cell line is highly sensitive for the isolation of foot-and-mouth disease virus (FMDV) and porcinophilic vesicular viruses. However, LFBK-α_vβ₆ cells are contaminated with a non-cytopathic bovine viral diarrhea virus (BVDV), which complicates handling procedures in areas where other cell lines are maintained, as well downstream use of viral isolates. In this study, we used an aromatic cationic compound (DB772) to treat LFBK-α_vβ₆ cells using an approach that has been previously used to eliminate persistent BVDV from fetal fibroblast cell lines. After three cell passages with 4 μM DB772, BVDV could no longer be detected in unclarified cell suspensions using a pan-pestivirus real-time RT-PCR assay, and remained undetectable after treatment was stopped (nine passages) for an additional 28 passages. The analytical sensitivity of the DB772-treated LFBK-α_vβ₆ cultures (renamed WRL-LFBK-α_vβ₆) to titrations of FMDV and other vesicular virus isolates was comparable to untreated LFBK-α_vβ₆ cells. These new BVDV-free cells can be handled without the risk of cross-contaminating other cells lines or reagents, and used for routine diagnostics, in vivo studies and/or preparation of new vaccine strains.

Feline immunodeficiency virus (FIV) is a naturally occurring T-cell tropic lentiviral disease of felids with many similarities to HIV/AIDS in humans. Similar to primate lentiviral-host interactions, feline APOBEC3 (A3) has been shown to inhibit FIV infection in a host-specific manner and feline A3 degradation is mediated by FIV Vif. Further, infection of felids with non-native FIV strains results in restricted viral replication in both experimental and naturally occurring infections. However, the link between molecular A3-Vif interactions and A3 biological activity during FIV infection has not been well characterized. We thus examined expression of the feline A3 genes A3Z2, A3Z3 and A3Z2-Z3 during experimental infection of domestic cats with host-adapted domestic cat FIV (referred to as FIV) and non-adapted Puma concolor FIV (referred to as puma lentivirus, PLV). We determined A3 expression in different tissues and blood cells from uninfected, FIV-infected, PLV-infected and FIV/PLV co-infected cats; and in purified blood cell subpopulations from FIV-infected and uninfected cats. Additionally, we evaluated regulation of A3 expression by cytokines, mitogens, and FIV infection in cultured cells. In all feline cells and tissues studied, there was a striking difference in expression between the A3 genes which encode FIV inhibitors, with A3Z3 mRNA abundance exceeding that of A3Z2-Z3 by 300-fold or more. Interferon-alpha treatment of cat T cells resulted in upregulation of A3 expression, while treatment with interferon-gamma enhanced expression in cat cell lines. In cats, secondary lymphoid organs and peripheral blood mononuclear cells (PBMC) had the highest basal A3 expression levels and A3 genes were differentially expressed among blood T cells, B cells, and monocytes. Acute FIV and PLV infection of cats, and FIV infection of primary PBMC resulted in no detectable change in A3 expression with the exception of significantly elevated A3 expression in the thymus, the site of highest FIV replication. We conclude that cat A3 expression is regulated by cytokine treatment but, by and large, lentiviral infection did not appear to alter expression. Differences in A3 expression in different blood cell subsets did not appear to impact FIV viral replication kinetics within these cells. Furthermore, the relative abundance of A3Z3 mRNA compared to A3Z2-Z3 suggests that A3Z3 may be the major active anti-lentiviral APOBEC3 gene product in domestic cats.

Despite the annual vaccination of livestock against foot and mouth disease (FMD) in the United Arab Emirates (UAE), outbreaks of the disease continue to be reported. The effective control of field outbreaks by vaccination requires that the vaccines used are antigenically matched to circulating field FMD viruses. In this study, a vaccine matching analysis was performed using the two-dimensional virus neutralization test (VNT) for three field isolates belonging to the O/ME-SA/PanAsia-2/ANT-10 and O/ME-SA/SA-2018 lineages collected from different FMD outbreaks that occurred within the Abu Dhabi Emirate in 2021 affecting Arabian oryx (Oryx leucoryx), goat, and sheep. In addition, post-vaccination antibodies in sheep and goats were measured using solid-phase competitive ELISA (SPCE) for FMDV serotypes A and O at five months after a single vaccine dose and a further 28 days later after a second dose of the FMD vaccine. An analysis of vaccine matching revealed that five out of the six vaccine strains tested were antigenically matched to the UAE field isolates, with r₁-values ranging between 0.32 and 0.75. These results suggest that the vaccine strains (O-3039 and O1 Manisa) included in the FMD vaccine used in the Abu Dhabi Emirate are likely to provide protection against outbreaks caused by the circulating O/ME-SA/PanAsia-2/ANT-10 and O/ME-SA/SA-2018 lineages. All critical residues at site 1 and site 3 of VP1 were conserved in all isolates, although an analysis of the VP1-encoding sequences revealed 14–16 amino acid substitutions compared to the sequence of the O1 Manisa vaccine strain. This study also reports on the results of post-vaccination monitoring where the immunization coverage rates against FMDV serotypes A and O were 47% and 69% five months after the first dose of the FMD vaccine, and they were increased to 81 and 88%, respectively, 28 days after the second dose of the vaccine. These results reinforce the importance of using a second booster dose to maximize the impact of vaccination. In conclusion, the vaccine strains currently used in Abu Dhabi are antigenically matched to circulating field isolates from two serotype O clades (O/ME-SA/PanAsia-2/ANT-10 sublineage and O/ME-SA/SA-2018 lineage). The bi-annual vaccination schedule for FMD in the Abu Dhabi Emirate has the potential to establish a sufficient herd immunity, especially when complemented by additional biosecurity measures for comprehensive FMD control. These findings are pivotal for the successful implementation of the region’s vaccination-based FMD control policy, showing that high vaccination coverage and the wide-spread use of booster doses in susceptible herds is required to achieve a high level of FMDV-specific antibodies in vaccinated animals.