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.

Severe PPR infection in gazelles kept under semi-free range conditions.

By the end of March 2002, a collection of some 200 gazelles, kept under semi range conditions in Saudi Arabia, was hit by a highly fatal peracute disease. The morbidity rate was 51% while the case mortality rate was 100%. Clinico-pathological and virological investigations were carried out. A virus was isolated from the ailing gazelles which was identified as Peste des Petits Ruminants virus (PPRV). Epidemiology of the disease in the Arabian peninsula is discussed.

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.

In vitro effects of some steroidal hormones on the replication of avian pneumovirus.

The effects of testosterone, oestradiol, progesterone and cortisone on the in vitro replication of avian pneumovirus in tracheal organ cultures (TOC) were investigated. Samples of cell-associated and cell-free virus from TOC, grown in medium containing these hormones, were taken at selected intervals. Progesterone and cortisone caused a slight increase in cell-associated virus. Testosterone and oestradiol caused a slight delay and decrease in virus replication when compared with the controls. All groups shared the same time interval to reach peak cell-free virus titre, 96 h post inoculation. In comparison with the controls, only a small drop (0.25-0.50 log10) in the peak of virus titre was observed in the hormone treated groups.

Epizootiological aspects of peste des petits ruminants and rinderpest in sheep and goats in Saudi Arabia.

Epizootiological aspects of peste des petits ruminants (PPR) and rinderpest in sheep and goats in Saudi Arabia are examined. The presence of PPR has been suspected on occasions, but virus isolation has been successful only once. Information regarding PPR and rinderpest in sheep and goats in Saudi Arabia is scarce. The only survey conducted indicated that neither disease is endemic in the country.

Observations on the recent epizootic of bovine ephemeral fever in Saudi Arabia.

Observations of the epizootic of bovine ephemeral fever which occurred in Saudi Arabia during 1996 are presented. The investigations included the collection of epidemiological data from affected farms and the testing of sera for antibodies to the virus. The authors report a mean morbidity rate of 50% and a mean case fatality rate of 0.3%. Of the infected cattle, 4% were affected by recumbency, the majority of these recovered (89%). The clinical signs observed in affected cattle were uniform throughout the region concerned. The features of the outbreak, obtained through field investigations, were considered in relation to the ecological and meteorological conditions which were prevalent at the time. The outbreak occurred during the summer months (May to October) in the central and eastern regions of Saudi Arabia, with the initial infection reported at the Al-Ahsa oasis. Farms which were subsequently affected were all reported to possess areas of stagnant water suitable for the reproduction of the vectors of the disease (Culicoides spp. and mosquitoes). To conclude, the authors discuss precautions to prevent future outbreaks of bovine ephemeral fever in Saudi Arabia.

Biochemical and hormonal changes associated with experimental infection of chicks with infectious bursal disease virus.

The inoculation of chicks with the infectious bursal disease (IBD) virus manifested typical clinical signs indicative of IBD viral infection. The inoculated birds seroconverted and showed significantly decreased total protein, lipid and a decrease in the albumin to globulin ratio. A significant increase was seen in the concentration of corticosterone and thyroxine but not in the triiodothyronine level.

Observations on African horse sickness in Saudi Arabia.

The present epidemiological status of African horse sickness in Saudi Arabia, as shown by seroconversion, virus isolation and clinical observation of sentinel horses is described. No African horse sickness virus activity was detected throughout the duration of the study (from November 1992 to March 1995). These findings support previous reports that African horse sickness is not endemic in Saudi Arabia.

Study of Akabane infection in Saudi Arabia by the use of sentinel ruminants.

Two sentinel herds of calves (Eastern and Central regions of Saudi Arabia) and one of sheep and goats (South Western region) were established to study Akabane virus infection. The herd at the Al-Ahsa oasis (Eastern region) showed evidence of Akabane viral activity, as reflected by the presence of maternal (colostral) antibody, which had waned to insignificant concentrations by the time the calves had reached the age of 5 months. There was no evidence of subsequent seroconversion. The other two sentinel herds gave no indication of Akabane viral activity.

A study on bluetongue virus infection in Saudi Arabia using sentinel ruminants.

Four sentinel herds comprising cattle, sheep and goats were established at various localities in Saudi Arabia. Maternal bluetongue antibodies were detected in all four sentinel herds but disappeared in 4-6 months, immediately followed by seroconversion in all. Serological results indicated that the animals were recently exposed to BT virus serotypes 10, 12, 15 and 20. The epidemiology of the disease in Saudi Arabia is discussed.

Prevalence of neutralizing antibodies to Akabane virus in ruminants in Saudi Arabia.

A total number of 2125 serum samples collected from indigenous sheep and goats and locally-raised cattle from different localities in Saudi Arabia, were screened for Akabane virus-neutralizing antibodies. The overall prevalence of antibodies was 32% in the animals examined. However the prevalence in cattle was 49%, while in sheep and goats it was 17%. No clinical cases of Akabane have been confirmed so far in Saudi Arabia; but virus isolation attempts are ongoing.

Effects of low doses of oestradiol, testosterone and dihydrotestosterone on the immune response of broiler chicks.

Administration of either 1 microgram kg-1 BW oestradiol 17 beta (E2), 0.1 mg kg-1 BW testosterone (T) or 0.2 mg kg-1 BW dihydrotestosterone (DHT) in feed to broiler chicks for 50 days caused increased serum concentration of the hormones compared to the control birds that were given no drugs. E2 and T but not DHT resulted in a significant decrease of the total number of leukocytes, lymphocytes and the weight of bursa of Fabricious. The hormones significantly reduced the macrophage phagocytic activity compared to controls. It is suggested that prolonged administration of low doses of E2 and T but not DHT to chicken may induce immunosuppressant effect.