Utilization of protein-A in immuno-histochemical techniques for detection of Peste des Petits Ruminants (PPR) virus antigens in tissues of experimentally infected goats.

This paper constitutes the first record of utilizing the S. aureus protein-A (PA), conjugated to peroxidase enzyme, for the detection of the Peste des Petits Ruminants (PPR) virus antigens in tissues of experimentally infected goats. The goats were experimentally infected with a virulent PPR virus, which was previously isolated from a severe natural disease outbreak in gazelles, during 2002 in Saudi Arabia. The technique is rapid, and has the superiority over the peroxidase -anti-peroxidase (PAP) test in that, inactivation of the indigenous peroxidase in the tissues is not required and that it can be used against a wide range of animal species. An advantage over the other immunolabelled conjugates is that PA attaches specifically to the crystalizable fraction (Fc) of the IgG molecule, thus allowing the antigen binding fraction (Fab) of the molecule, free to interact specifically with the antigen. So, it doesn't actually compete with the antigen for the Fab portion of the IgG molecule. In the present study, PA conjugate detected the PPR virus antigens in various tissues of the experimentally infected goats.

Severe malformations in calves associated with bovine viral diarrhoea (BVD) virus infection in a dairy cattle herd.

During late may 2004, Some dairy cows at Al-Kharj area of central Saudi Arabia, gave birth to severely malformed calves which died, few hours to few days following birth. Samples were collected from the affected calves and their dams of virological and serological investigations. Bovine viral diarrhoea virus was detected by capture enzyme linked immuno-sorbent assay (ELISA) in the brains of affected calves. Serum antibodies were detected in the dams. The present study indicated that in spite of vaccination against BVD in the country, still severe affections of the disease are encountered. Further insight epidemiological studies to elucidate the BVD situation in Saudi Arabia is urgently needed.

Pseudocowpox virus: the etiological agent of contagious ecthyma (Auzdyk) in camels (Camelus dromedarius) in the Arabian peninsula.

We have determined the nucleotide sequence of DNA extracted from pustules, saliva, and blood of camels presenting with contagious ecthyma, in Bahrain and also from a sample (SACamel) of infected tissue from a camel that had presented with contagious ecthyma in 1998 in Saudi Arabia (1). Sequence homologies and phylogenetic analysis showed that this extracted DNA was more closely related to Pseudocowpox virus (PCPV) than Orf virus (ORFV), which infects sheep, goats, and other animal species. The phylogeny also demonstrated that PCPV in Arabian camels was phylogenetically distinct from, and circulates independently of, ruminant-associated PCPV from Europe.

Phylogenetic analysis of rabbit haemorrhagic disease virus strains from the Arabian Peninsula: did RHDV emerge simultaneously in Europe and Asia?

Rabbit haemorrhagic disease virus (RHDV) emerged in 1984 in China and subsequently a single strain apparently dispersed worldwide killing millions of rabbits. Two isolates that caused outbreaks in Saudi Arabia and Bahrain have been sequenced and analysed phylogenetically. The Saudi Arabian lineage is directly descended from the Chinese strain, but the Bahrain isolate occupies a distinct and more divergent lineage than the Chinese virus implying that epidemic RHDV strains have emerged at least twice during the past 20 years and are co-circulating in both domestic and wild rabbits.

A study on bovine ephemeral fever involving sentinel herds and serosurveillance in Saudi Arabia.

A nationwide study was conducted in Saudi Arabia to determine if bovine ephemeral fever (BEF) was present in cattle between 1993 and 1995. The study had two components: the first was establishment of sentinel herds of cattle in some localities, the second was to conduct a nationwide serological survey. The results indicated that Saudi Arabia was free of BEF during the period of study and that the cattle population was susceptible to the disease, which may have contributed to the fulminating epidemic of 1996. The epidemiological situation of the disease in Saudi Arabia is discussed in relation to the likelihood of introduction of the disease into the country.

Abortions, stillbirths and deformities in sheep at the Al-Ahsa oasis in eastern Saudi Arabia: isolation of a bluetongue serogroup virus from the affected lambs.

A wave of abortions, stillbirths and deformities in sheep occurred at the Al-Ahsa oasis in the eastern region of Saudi Arabia in the second half of 1999. The abortions were recorded in August and September and stillbirths and deformities in neonates were observed in October. Adult sheep were clinically normal. A virus was isolated in chicken embryos, adapted to Vero cell culture and further identified as bluetongue (BT) virus. The virus isolated was not neutralised by the Akabane virus. Reference hyperimmune serum against antibodies to BT virus detected in the sera of the dams gave positive results for BT but negative results for both Akabane and bovine viral diarrhoea virus. It was concluded that the outbreak was caused by a virus of the BT serogroup. The authors present the clinico-pathological and epidemiological situation of the disease outbreak.

Sheep-associated malignant catarrhal fever involving 3-5-week-old calves in Saudi Arabia.

Between late December 1999 and late April 2000, three locally bred Friesian calves (ageing 25, 28 and 35 days) in a dairy farm, at Al-Ahsa locality of the eastern region of Saudi Arabia showed dullness and inappetence. Their rectal temperatures ranged between 41 and 41.5 degrees C. One to 2 days later and onwards, the calves showed lacrimation, nasal discharge, salivation, oedema of the head, conjunctivitis, exo-ophthalmia and corneal opacity. One calf showed diarrhoea. The superficial lymph nodes were oedematous and swollen. The calves died after 7, 5 and 8 days, respectively, following the onset of the disease. Calves and rabbits were experimentally infected with materials from the naturally infected calves. The rabbits showed fever, mild conjunctivitis and one rabbit showed wet faeces. The experimentally inoculated calves showed rise in temperature and mild symptoms but none of them died. The virus from the naturally infected calves and from the experimentally infected rabbits was identified as malignant catarrhal fever (MCF) virus using both the complement fixation test and the fluorescent antibody test, employing a reference anti-serum against the WC 11 strain of MCF virus. Serological survey for MCF antibodies in cattle, sheep and goats from the affected farm revealed that 54% of the examined animals were positive. The situation of MCF in Saudi Arabia was discussed in relation to sheep and wild game. This paper constitutes the first report of MCF in Saudi Arabia and the Gulf region.

A retrospective study of Rift Valley fever in Saudi Arabia.

A retrospective study was undertaken to examine domestic ruminant sera for Rift Valley fever (RVF) virus antibodies. The sera were collected between 1992 and 1995 from cattle, sheep and goats from various locations in Saudi Arabia. The standard capture enzyme-linked immunosorbent assay system was employed to detect specific RVF antibodies in the animals and the results indicated an absence of RVF antibodies. This finding confirms the assumption that Saudi Arabia was free from RVF up until at least 1995 and most probably before the 2000 epidemic. The finding also confirms that RVF was not endemic in Saudi Arabia.

Seasonal abundance of four Culicoides spp. (Diptera: Ceratopogonidae) at Al-Ahsa oasis, Eastern Province, Saudi Arabia.

This report constitutes the first study of Culicoides spp. and their seasonal abundance at Al-Ahsa, the largest oasis in the Eastern Province of Saudi Arabia. New Jersey light traps were used to collect the midges at Mastock farm and Al-Mansura village. The mean monthly abundance was determined from October 1993 to October 1994. The mean monthly number per trap reached its minimum value during January 1994, increasing gradually from February to reach its maximum value during September 1994. During the study period, the following species were collected: Culicoides schultzei group (September), non-spotted group of Culicoides (September), Culicoides imicola (May) and Culicoides newstaedi (March). The potential importance of the Culicoides spp. in relation to arboviral activity in Saudi Arabia is discussed.