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BACKGROUND African horse sickness (AHS) is a devastating viral disease of equids that was first recorded in 1327. Currently, prevention and control of the disease are based on attenuated vaccines and midge control. It has been shown that attenuated Orbivirus vaccines are not always safe as they may reverse to virulence. OBJECTIVES In the Emirate of Dubai, a vaccination experiment was carried out with an inactivated AHS vaccine produced at the Central Veterinary Research Laboratory (CVRL), Dubai, UAE to investigate the humoral antibody response of AHS-naive horses to this vaccine. Our vaccination experiment was performed to establish an AHS vaccine bank in the UAE to protect horses from the disease in case of an outbreak. Therefore, CVRL established an inactivated AHS vaccine containing all nine serotypes which induce high neutralising antibodies. STUDY DESIGN A total of 10 horses kept in a desert isolation area were subcutaneously and intramuscularly vaccinated with an inactivated vaccine containing all nine AHS serotypes previously isolated from Kenyan horse fatalities. Primary immunisation was followed by two booster immunisations 4 weeks and 6 months apart. After 13 months, an annual booster was administered. METHODS Blood samples were regularly withdrawn for ELISA and virus neutralisation testing. Additionally, EDTA blood was tested every second day for 14 days post each vaccination for the presence of AHS virus or its RNA. RESULTS Results show that ELISA and virus neutralising antibodies appeared after the first booster, declined after 4-6 months and therefore three vaccinations and an annual vaccination are necessary to achieve high protective virus neutralising antibodies. MAIN LIMITATIONS No challenge infection was carried out due to the lack of a safe facility in the UAE. CONCLUSION Before more advanced AHS vaccines become a reality, inactivated vaccines containing all nine serotypes should be used as they produce high ELISA and neutralising antibodies.

Cloning (SCNT) in avian species has proven unachievable due to the physical structure of the avian oocyte. Here, the plasticity of sexual differentiation of male primordial germ cells (PGCs) was investigated in opposite sex chimeric chicken hosts with the aim of producing uniparent clones. Male (ZZ) PGCs were expanded in culture and transplanted into the same and opposite sex chicken host embryos which were partially sterilized using γ-irradiation. As expected, all (28/28) chimeric (ZZ) roosters showed germline transmission with transmission rates of 3.2- 91.4% as detected by feather color. Unexpectedly, functional oogenesis of male chicken PGCs was found in three chimeric (ZW) hens (3/27), resulting in transmission rates of 2.3- 27.8%. Matings were conducted between the male and female germline chimeras which derived from the same male PGC line. 20 uniparent chicken clones were obtained with a transmission rate up to 28.4% and as expected, all uniparent offspring were male (ZZ). A genotype analysis was performed on 6 offspring using 13 microsatellite markers. The genotype profile of these offspring showed that uniparent offspring were 100% genetically identical to the donor male PGC line, and shared 69.2-88.5% identity with the donor bird at the 13 loci. At the 13 loci, homozygosity of the tested birds varied from 61.5-84.6%, which was higher than that of the donor bird (38.5%). These results demonstrate that male avian PGCs can differentiate into functional ova in an ovary and uniparent avian clones are possible. Uniparent clones differ from SCNT clones as the mitochondrial DNA derives from the donor and not from the host. This technology suggests novel approaches for generating genetically similar flocks of birds and for the conservation of avian genetic resources. Forming uniparent clones in bird species could be useful in extreme cases of low populations size.

The objectives of the present study were to monitor the microbiological quality and somatic cell count (SCC) of bulk tank milk at the world's first large-scale camel dairy farm for a 2-yr period, to compare the results of 2 methods for the enumeration of SCC, to evaluate correlation among milk quality indicators, and to determine the effect of specific factors (year, season, stage of lactation, and level of production) on milk quality indicators. The study was conducted from January 2008 to January 2010. Total viable count (TVC), coliform count (CC), California Mastitis Test (CMT) score, and SCC were determined from daily bulk milk samples. Somatic cell count was measured by using a direct microscopic method and with an automatic cell counter. In addition, production parameters [total daily milk production (TDM, kg), number of milking camels (NMC), average milk per camel (AMC, kg)] and stage of lactation (average postpartum days, PPD) were recorded for each test day. A strong correlation (r = 0.33) was found between the 2 methods for SCC enumeration; however, values derived using the microscopic method were higher. The geometric means of SCC and TVC were 394 × 103 cells/mL and 5,157 cfu/mL during the observation period, respectively. Somatic cell count was >500 × 103 cells/mL on 14.6% (106/725) and TVC was >10 × 103 cfu/mL on 4.0% (30/742) of the test days. Both milk quality indicators had a distinct seasonal pattern. For log SCC, the mean was lowest in summer and highest in autumn. The seasonal pattern of log TVC was slightly different, with the lowest values being recorded during the spring. The monthly mean TVC pattern showed a clear difference between years. Coliform count was