Detection of foot-and-mouth disease viruses from the A/AFRICA/G-I genotype in the Sultanate of Oman.

Rapid identification and characterization of circulating foot-and-mouth disease virus (FMDV) strains is crucial for effective disease control. In Oman, a few serological and molecular studies have been conducted to identify the strains of FMDV responsible for the outbreaks that have been occurring within the country. In this study, 13 oral epithelial tissue samples from cattle were collected from suspected cases of FMD in Ash Sharqiyah North, Al Batinah North, Dhofar and Ad Dhakhyilia governorates of Oman between 2018 and 2021. FMDV RNA was detected in all samples by real-time RT-PCR and viruses were isolated after one- or two-blind passages in the porcine Instituto Biologico-Rim Suino-2 cell line. Antigen capture ELISA characterized all isolates as serotype A and VP1 phylogenetic analysis placed all sequences within a single clade of the G-I genotype within the A/AFRICA topotype. These sequences shared the closest nucleotide identities to viruses circulating in Bahrain in 2021 (93.5% to 99.5%) and Kenya in 2017 (93.4% to 99.1%). To the best of our knowledge, this is the first time that A/AFRICA/G-I viruses have been detected in Oman. Together with the closely related viruses detected recently in Bahrain, these findings reinforce the importance of deploying effective quarantine control measures to minimize the risks of transboundary transmission of FMD associated with the importation of cattle from East Africa.

Natural Burkholderia mallei infection in Dromedary, Bahrain.

We confirm a natural infection of dromedaries with glanders. Multilocus variable number tandem repeat analysis of a Burkholderia mallei strain isolated from a diseased dromedary in Bahrain revealed close genetic proximity to strain Dubai 7, which caused an outbreak of glanders in horses in the United Arab Emirates in 2004.

Induction of alpha and beta chemokines by intestinal epithelial cells stimulated with Campylobacter jejuni.

OBJECTIVES: To investigate the production of dynamic alpha and beta chemokines represented by interleukin-8 (IL-8) as alpha chemokine and CCL2 (monocyte-chemoattractant protein-1, CCR2 ligand), CCL4 (macrophage-inflammatory protein-1beta, CCR5 ligand), CCL3 (macrophage-inflammatory protein-1alpha, CCR1/5 ligand), (CCL5, regulated upon activation, normal T-cell expressed and secreted (RANTES, CCR5 ligand) as beta chemokines by the human intestinal cell line INT407 stimulated with factors produced by living Campylobacter jejuni (C. jejuni) and those present within sonicated and filtrated bacteria. METHODS: We used immunohistochemical technique modified to detect intracellular production of cytokines protein and RT-PCR to read RNA messages for evaluation of de novo cytokine synthesis. RESULTS: Living bacteria induced increased numbers of IL-8, CCL4 and CCL2 but not CCL3 or CCL5 producing cells. Low numbers of IL-8, CCL4 and CCL2 producing cells were detected with filtrated supernatant compared to living and sonicated bacteria. A non-significant low number of chemokine producing cells was noted when comparing numbers of chemokine producing cells stimulated with living C. jejuni to those stimulated with sonicated bacteria, indicating that the triggering factors involved in stimulation with living bacteria were still active after sonication, but they were largely lost upon filtration. The mRNA signals for IL-8 were noted in conformity with its protein levels as increased IL-8 mRNA signals were registered after stimulation with living and sonicated bacteria but not with filtrated supernatant. CONCLUSIONS: Preferential production of chemokines probably induced by membrane associate factors of C. jejuni acting on intestinal epithelial cells is presented. These chemokines are suggested to be part of an inflammatory network affecting cell types that contribute to initiation and/or resolution of the infection.

Campylobacter-stimulated INT407 cells produce dissociated cytokine profiles.

OBJECTIVES: To study the action of factors produced by living Campylobacter jejuni (C. jejuni) against those present within sonicated and filtrated bacteria on induction of potential cytokines by the human intestinal cell line INT407. METHODS: We used immunohistochemical technique modified to detect intracellular production of cytokines protein and RT-PCR to read RNA messages for evaluation of de novo cytokine synthesis. RESULTS: The data herein display dissociation of cytokine profiles induced on by living C. jejuni. Exposure of INT407 cells to 10(6) live bacteria showed the highest numbers of cytokine producing cells of all examined cytokines. IFN-gamma was the highest induced cytokine followed by IL-10, TNF-alpha and lastly IL-4. Also, abrogation of induction of the proinflammatory cytokines IFN-gamma and TNF-alpha but not the antiinflammatory cytokines IL-4 and IL-10 by sonicated and filtrated bacteria was depicted. At the mRNA level, TNF-alpha signals were noted in accordance with its protein levels since increased TNF-alpha mRNA signals were registered only after stimulation with living bacteria. Very low or no induction of TNF-alpha was registered with non-stimulated cells. CONCLUSIONS: These results illustrate for the first time a role for factors from living bacteria in directing the immune response towards Th1 type. Characterization of such factors may be essential for future immunotherapeutic interventions during severe bacterial infections.