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Yousif, A. A., L. J. Braun, M. S. Saber, T. Aboelleil, and C. C. L. Chase, "Cytopathic genotype 2 bovine viral diarrhea virus in dromedary camels", Arab J. Biotech, vol. Vol. 7, issue 1, pp. 123-140, 2003. pesti_in_camels.pdf
Yousif, A. A., and A. A. Al-Naeem, Recovery and molecular characterization of live Camelpox virus from skin 12 months after onset of clinical signs reveals possible mechanism of virus persistence in herds, , vol. 159, issue 3–4, pp. 320 - 326, 2012/10/12/. AbstractWebsite

Potentially pathogenic orthopoxviruses (OPVs) persist in nature and re-emerge for reasons we do not fully understand. New information pertaining to Orthopoxvirus (OPV) persistence in nature would significantly improve surveillance and control programs. In a recent investigation of a Camelpox virus (CMLV) outbreak in Eastern Saudi Arabia, atypical minute pox-like skin lesions (AMPL) persisted on 42.9% of convalescent camels (8.8% of herd) for more than a year after the onset of clinical signs. In order to investigate whether AMPL were related to CMLV infection, AMPL homogenates were inoculated on the chorioallantoic membranes (CAM) of specific-pathogen-free (SPF) embryonating chicken eggs (ECE). Live CMLV was recovered from AMPL homogenates. The sequences of the ATIP gene of viruses isolated in the beginning of the outbreak, and one year later from AMPL were identical, and similar to the Kazakhstan isolate CMLV M-96. Virus identity was confirmed by sequence analysis of the CMLV A33R, A27L, B5R, and L1R orthologue genes. Uninfected adult camels that came in contact with animals showing AMPL became infected within two weeks. Since AMPL were easily missed by veterinarians and camel drivers, it was concluded that CMLV survival in persistent skin lesions may be a key mechanism in maintaining the virus in previously infected camel herds during inter-epizootic periods.

Yousif, A. A., and A. A. Al-Naeem, "Molecular Characterization of Enzootic Camelpox Virus in the Eastern Kingdom of Saudi Arabia", International Journal of Virology, vol. 7, issue 4 , pp. 135-146, 2011. cmlvijv.pdf
Yousif, A. A., and A. M. Al-Ali, A case of mistaken identity? Vaccinia virus in a live camelpox vaccine, , vol. 40, issue 6, pp. 495 - 498, 2012/11//. AbstractWebsite

Live-attenuated (LA), and inactivated adjuvant (IA) camelpox virus (CMLV) vaccines are produced in several countries worldwide. A tissue culture attenuated CMLV isolated (Jouf-78) is used to produce an LA vaccine in Saudi Arabia (Hafez et al., 1992). DNA extracts from the Saudi LA vaccine were used as positive controls for a routine ATIP PCR produced fragments longer than 881 bp. PCR-amplified ATIP sequences were similar to vaccinia virus (VACV) Lister strain. PCR and sequence analysis of two extracellular enveloped virus (EEV)-specific (A33R and B5R), and two intracellular mature virus (IMV) (L1R and A27L) othrologue genes from the vaccine DNA extracts confirmed the finding. CMLV sequences were not detected in vaccine DNA extracts. A VACV Lister strain imported from Switzerland was used in control experiments during initial testing of the Saudi LA vaccine. High antigenic similarity between VACV and CMLV, and a possible contamination event during production may have caused this issue. Environmental and health impact studies were recommended because early VACV vaccines produced in some European countries contained nonhighly attenuated strains that were not adequately screened for adventitious agents.

Yousif, A. A., A. A. Al-Naeem, and A. M. Al-Ali, Rapid non-enzymatic extraction method for isolating PCR-quality camelpox virus DNA from skin, , vol. 169, issue 1, pp. 138 - 142, 2010/10//. AbstractWebsite

Molecular diagnostic investigations of orthopoxvirus (OPV) infections are performed using a variety of clinical samples including skin lesions, tissues from internal organs, blood and secretions. Skin samples are particularly convenient for rapid diagnosis and molecular epidemiological investigations of camelpox virus (CMLV). Classical extraction procedures and commercial spin-column-based kits are time consuming, relatively expensive, and require multiple extraction and purification steps in addition to proteinase K digestion. A rapid non-enzymatic procedure for extracting CMLV DNA from dried scabs or pox lesions was developed to overcome some of the limitations of the available DNA extraction techniques. The procedure requires as little as 10 mg of tissue and produces highly purified DNA [OD260/OD280 ratios between 1.47 and 1.79] with concentrations ranging from 6.5 to16 μg/ml. The extracted CMLV DNA was proven suitable for virus-specific qualitative and, semi-quantitative PCR applications. Compared to spin-column and conventional viral DNA extraction techniques, the two-step extraction procedure saves money and time, and retains the potential for automation without compromising CMLV PCR sensitivity.

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