Serological tests may represent an essential tool for the diagnosis of camel brucellosis; however, concerns arise in the scientific community regarding the direct transposition from cattle and small ruminants without adequate validation. The present study was made to compare four serological tests for the diagnosis of brucellosis in dromedary camels (Camelus dromedarius). In terms of sensitivity, our results show that the Immunochromatographic Test (ICT) shows the higher value of sensitivity, 98.67% (95% Confidence Level (C.L): 94.36–99.99%), followed by the Fluorescence Polarization Assay (FPA) with 95.05% (95% C.L: 88.23–99.51%), then the Competitive Enzyme-Linked Immunosorbent Assay (c-ELISA) with 94.94% (95% C.L: 88.25–99.45%) and, finally, the Rose Bengal Test (RBT) with 68.95% (95% C.L: 56.55–80.69%), which is the only test showing a significantly lower sensitivity compared to the others. On the other hand, our study revealed no significant difference in terms of specificity between all the tests under study, with a range from 99.06% (95% C.L: 98.34–99.64%) for the ICT to 99.92% (95% C.L: 99.64–100%) for the RBT. The ICT was found to be comparable in terms of sensitivity and specificity with the most commonly used tests for camel brucellosis. The results of the present study are of paramount importance for designing surveillance and control measures for brucellosis in camel populations.

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.

Background: Peste des petits ruminants (PPR) is an acute or subacute contagious trans-boundary viral disease causing high morbidity and mortality in domestic and wild small ruminants. The national UAE-PPR control and eradication plan follows the PPR Global Control and Eradication Strategy (PPR GCES) and relies on the annual mass vaccination of small ruminants to eradicate the disease from the country by 2030. Despite the immunization effort against PPR, the vaccination coverage reached 65% at maximum, which necessitates conducting a post-vaccination evaluation (PVE) study at the national level. Methods: Using multistage random sampling to assess the PPR vaccine and vaccination effectiveness, protocol (2) of the PPR GCES, using two serosurveys; serosurvey (1) (pre-vaccination) at day 0 before vaccination, to assess the primary PPR serological investigation, and serosurvey (2) at (30–90) days post-PPR vaccination, to evaluate the immune response, were carried out from September to December 2024 across the seven Emirates of the UAE. The nucleoprotein-based competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect PPR antibodies in a total of 1592 and 1589 sera samples collected, respectively, before and after vaccination from different (n = 163) sheep and goats holdings (epi-unit) distributed in the different Emirates of the UAE. Results: In serosurvey (1). prior to vaccination, out of the total 1592 samples tested (839 goats and 753 sheep), 833 animals (52.32%) were found to be seropositive for PPR antibodies. In contrast, in serosurvey (2), after vaccination, 1490 (93.77%) animals were found to be seropositive out of the total 1589 small ruminants (825 goats and 764 sheep) tested by c-ELISA. A statistically significant increase (41.45%) in the overall seroprevalence from (52.32%) pre-vaccination to (93.77%) post-vaccination was observed. Post-vaccination, 93.87% (n = 153) of the vaccinated epi-units achieved more than 70% seroprevalence compared to 43.56% (n = 71) before vaccination. Prediction analysis showed that all the seven UAE Emirates require 1.2 years maximum to reach 100% immune-protection levels. Conclusions: An efficient PPR vaccine was used to immunize small ruminants in the UAE. Higher (89.47–100%) post-vaccination herd immunity than the threshold recommended by the PPR GCES (>80% immunity) was attained, which can efficiently break the spread of PPRV within the UAE. To enhance the eradication of PPR I the UAE, conducting mass vaccination campaigns targeting over the (95%) immunization coverage of eligible animals for the next three years is recommended to attain the requested sustained (>80%) immunity at the animals holding level.