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An investigation into the possibility of bluetongue virus transmission by transfer of infected ovine embryos
2011
Estelle H. Venter | Truuske Gerdes | Isabel Wright | Johan Terblanche
Bluetongue (BT), a disease that affects mainly sheep, causes economic losses owing to not only its deleterious effects on animals but also its associated impact on the restriction of movement of livestock and livestock germplasm. The causative agent, bluetongue virus (BTV), can occur in the semen of rams and bulls at the time of peak viraemia and be transferred to a developing foetus. The risk of the transmission of BTV by bovine embryos is negligible if the embryos are washed according to the International Embryo Transfer Society (IETS) protocol. Two experiments were undertaken to determine whether this holds for ovine embryos that had been exposed to BTV. Firstly, the oestrus cycles of 12 ewes were synchronised and the 59 embryos that were obtained were exposed in vitro to BTV-2 and BTV-4 at a dilution of 1 x 102.88 and 1 x 103.5 respectively. In the second experiment, embryos were recovered from sheep at the peak of viraemia. A total of 96 embryos were collected from BTV-infected sheep 21 days after infection. In both experiments half the embryos were washed and treated with trypsin according to the IETS protocol while the remaining embryos were neither washed nor treated. All were tested for the presence of BTV using cell culture techniques. The virus was detected after three passages in BHK-21 cells only in one wash bath in the first experiment and two unwashed embryos exposed to BTV-4 at a titre of 1 x 103.5. No embryos or uterine flush fluids obtained from viraemic donors used in the second experiment were positive for BTV after the standard washing procedure had been followed. The washing procedure of the IETS protocol can thus clear sheep embryos infected with BTV either in vitro or in vivo.
Afficher plus [+] Moins [-]Sheep Oestrosis (Oestrus Ovis, Diptera: Oestridae) in Damara crossbred sheep
2011
Wan S. | Kamaliah G. | Rugayah M. | Osman M. A. | Gunalan S. | Nabijah D. | Rozita A. R. | Shah A.
Oestrosis is a worldwide myiasis infection caused by the larvae of
the fly Oestrus ovis (Diptera, Oestridae), that develops from the first to the third stage larvae. This is an obligate parasite of the nasal and sinus cavities of sheep and goats. The Oestrus ovis larvae elicit clinical signs of cavitary myiasis seen as a seromucous or purulent nasal discharge, frequent sneezing, incoordination and
dyspnea. Myiasis in an incidental host may have biological significance towards medical and public health importance if
the incidental host is man. This infection can result in signs of generalized disease, causing serious economic losses in sheep and goat reared for meat and dairy production. Due to the large numbers of small ruminants imported into Malaysia from countries which are endemic with oestrosis, precautionary measures should be exercised to prevent this infection from establishing here. In 2009, there was a report of respiratory distress (pneumonic sign) accompanied by high mortality in Damara sheep that was imported from Australia. Investigations showed the presence of Oestrus ovis larvae in affected
sheep. The post mortem was conducted in the field and the larvae were discovered in the tracheal region. The larvae was confirmed as Oestrus ovis using the appropriate keys for identification by Zumpt. The carcass showed pulmonary edema with severe congestion of the lungs accompanied by frothy exudation in the bronchus. There were also signs of serious atrophy (heart muscle) and mild enteritis
(intestine histopathological examination showed, there was pulmonary congestion and edema, centrilobular hepatic necrosis, renal tubular necrosis and myocardial sarcocystosis. The sheep also showed chronic helminthiasis and Staphylococcus spp. was isolated from organ specimens.Oestus ovis infection is rare in Malaysia, as such this case posed as an unusual case for investigation.
Afficher plus [+] Moins [-]Isolation of Streptococcus equi during strangles surveillance in Peninsular Malaysia
2011
Yosnah Y. | Maswati M. A. | Saifu Nazri. R. | Khoo, l. l. | Roseliza R. | Ramlan M.
Strangles is an extremely contagious bacterial infection specific to
equine species( horses, mules and zebras). A nationwide screening of S. equi was conducted among horses following an isolation of Streptococcus equi subsp. equi (S. equi) from a horse. All horses were monitored for the presence of respiratory signs, nasal discharge and submandibular swelling. This paper reports the isolation of S. equi from horses during a nationwide survey from August 2010 to December 2010. From August 2010 to December 2010 our laboratory received 2,825 nasal swabs, 9 guttural pouch flushes, 1 submandibular swab and 1 submandibular abscess. The samples were subjected to conventional bacterial isolation and identification.
Streptococcus equi-positive samples were also confirmed by detecting the M-gene (SeM) of the bacteria by using PCR. Two nasal swabs from two horses and one submandibular abscess from a horse were positive for S. equi by culture and subsequently by PCR. Surveillance for S. equi should be continued for the control of the strangles. PCR can be carried out in parallel to bacterial culture to increase the
detection rate of carriers and shedders.
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