Recent studies have shown that the gut microbiota modulates the physical and psychological functions of the host through several modes of action. One of them is mediating the production of active neurotransmitters, such as serotonin and gamma-aminobutyric acid (GABA). GABA is the major inhibitory neurotransmitter in the central nervous system. Here, we analyzed the relationship between fecal GABA concentration and microbial composition in more than 70 human participants. The gut microbiome composition was analyzed using next-generation sequencing based on 16S ribosomal RNA. High-performance liquid chromatography was used to evaluate the neurotransmitters GABA and glutamate. The GABA level was detected in a broad range (0–330 µg/g feces). The participants’ samples were classified into high (>100 µg/g), medium (10–100 µg/g), and low (<10 µg/g) groups, based on fecal GABA concentration. The results reveal that the microbiome of the high-GABA samples had lower alpha diversity than the other samples. Beta diversity analysis showed significant (p < 0.05) separation between the high-GABA samples and others. Furthermore, we surveyed the abundance of specific GABA producer biomarkers among the microbiomes of tested samples. The family Bifidobacteriaceae exhibited high abundance in the microbiome of the high-GABA group. This study demonstrated that Bifidobacterium abundance was associated with high fecal GABA content in healthy human subjects. These results may aid the development of potential probiotics to improve microbial GABA production, which can support the maintenance of the physical and psychiatric health of the host.

Lumpy skin disease (LSD) is an emerging disease of cattle causing significantly high economic losses. Control of LSD depends on the use of homologous attenuated LSD virus strains isolated originally from South Africa (the Neethling strain). The virus belongs to the genus Capripoxvirus, which includes sheep pox virus and goat pox virus. The present study was conducted to evaluate the safety and efficacy of a new live attenuated LSD vaccine produced by Middle East for Vaccines (MEVAC^®) based on the Neethling strain. Tests were performed both in Egypt and Vietnam. Safety was evaluated by inoculation of five cattle with 10 times the recommended dose and observation of the animals for 14 days. Immunogenicity was tested at different periods post-vaccination (PV) in animals receiving the recommended doses of the vaccine using ELISA and virus neutralization test. Five cows were used to determine the protection index (PI) and non-vaccinated control cattle were included. Three calves were challenged by intradermal inoculation of the wild virus (5 × 10⁵ TCID₅₀) 28 days PV. Field or mass vaccination experiments were conducted in Vietnam during national campaigns in the summer of 2021 with 4301 vaccinated animals closely monitored after vaccination. In the field, around 2% (80/4301) of the animals showed hyper-reactivity, and 0.6% (24/4301) showed small skin swellings that disappeared within few hours PV. Abortion was recorded in three animals (0.3% 3/867). Challenged animals were resistant to clinical disease and PI value was 3.5 log₁₀. Meanwhile, antibody levels determined by the ELISA were inconsistent among animals and laboratories during the study period. Overall, the findings point to a new safe and effective LSD vaccine.

Foot-and-mouth disease (FMD) is a serious highly contagious viral disease affecting all cloven-hoofed animals, and outbreaks can have a severe economic impact. An inactivated heptavalent oil-adjuvanted FMD vaccine (Aphtovac-7, MEVAC) was prepared from the foot-and-mouth disease virus (FMDV) strains A-Iran05, A-Africa-IV, O-PanAsia2, O-Manisa, O-EA3, SAT-2 Gharbia, and SAT-2 LIB-12. The vaccine potency and effectiveness were evaluated in three groups of 6- to 8-month-old calves and 200 adult dairy cattle under field conditions. All animals were vaccinated with the vaccine preparation, and the three groups of calves were challenged after 28 days by intradermolingual inoculation with 10⁴ 50% tissue culture infective dose (TCID₅₀) of FMDV serotype A, O, or SAT-2. Mock-vaccinated calves (two per group) served as unvaccinated controls during the challenge test. Adult dairy cattle were tested for seroconversion using a virus neutralization test at 30, 60, and 120 days post-vaccination. All calves displayed complete protection against challenge with the different serotypes of FMDV when compared to the control groups. Serum samples collected after the primary and booster immunizations at 30 days post-vaccination contained high titers of protective antibodies (≥ 1/32; i.e. 1.5 log₁₀). Antibodies persisted until the end of the study period (120 days), with a peak value around 60 days post-vaccination. The heptavalent FMD vaccine preparation was found to be potent and capable of providing a protective immune response under both experimental and field conditions.