The value of camels as sentinels for bluetongue virus in Morocco.

A  serosurvey  was  conducted  to  determine  the  value  of  camels  (Camelus  dromedaries)  as sentinel animals for the detection of bluetongue virus (BTV) in Morocco. Between 2010 and 2013, camels from various localities in Morocco were randomly tested for antibodies against BTV  serotypes­1,  ­4,  ­6,  ­8,  ­11,  ­14,  and  ­16.  Antibodies  against  1  or  more  serotypes  were detected in 41.8% of 537 camels tested with a competitive enzyme­linked immunosorbent assay  (ELISA)  diagnostic  test.  Of  the  7  tested  serotypes,  only  BTV­11  antibodies  were  not detected with serum neutralisation assays. This study not only confirms the epidemiological presence of BTV­1, ­4, and ­8 in Morocco, but also presents the first evidence of BTV­6, ­14, and ­16 in the country. As such, we conclude that camels would be ideal sentinel animals to determine the potential risk of BTV in Morocco.

Isolation and identification of group A rotaviruses among neonatal diarrheic calves, Morocco.

BACKGROUND: Group A rotaviruses (RVA) are the main cause of neonatal calve diarrhea (NCD) in Morocco. In this study, we isolated RVA strains from NCD clinical samples in order to support RVA disease control in Morocco. This isolation process constitutes a first step toward vaccine development. METHODS: Thirteen fecal samples were obtained from calves with a single episode of neonate calf diarrhea at three different dairies and two samples were collected from field during a severe NCD outbreak. Diagnosis of RVA infection was based on fecal immune-chromatographic rapid test and further evaluated for their hemagglutination (HA) activity. RVA isolation was carried out on MA104 cells after inoculates were treated with different concentrations of trypsin TPCK. All RVA isolates were confirmed by LSI VetMAX™ Triplex Ruminant Rotavirus & Coronavirus Real-Time PCR kit. G and P typing were determined by direct sequencing of the VP4 and VP7 amplicons. RESULTS: RVA isolation was achieved for nine clinical samples following one or two passages (60 %) and was properly depended on HA activity and trypsin treatment of inoculates. The first sign of CPE detected consisted of increased cell granularity, obscure cell boundaries, cell rounding, and eventual degeneration and detachment of cells. At lower TPCK concentration (3-10 µg/inoculum), no changes at the cellular level were observed, while cells activated with 25-30 µg of trypsin/inoculums, they degenerated and trypsin cytotoxicity was enhanced. Appreciable changes in cell's morphology were detected with optimal trypsin concentration of 15-20 µg trypsin/inoculums. Data from qRT-PCR confirmed that unsuccessful cultivations have No-Ct, and all nine isolates have Ct values ranged between 12.17 and 24.69. Analysis sequencing revealed that field isolates were of G6 P[5] serotype and isolates from the dairy NCD samples were of G10 P[14] serotype. CONCLUSIONS: To our knowledge, this is the first study in Morocco which reports the circulation of G10P[14] in NCD on dairy farms and G6P[5] in the field. Our study constitutes a crucial and a necessary step allowing preventive and veterinary medicine to support RVA disease controls in the country.

A reliable and reproducible experimental challenge model for peste des petits ruminants virus.

Experimental challenge protocols that consistently reproduce clinical signs of peste des petits ruminants in Alpine goats infected with a tissue culture-passaged peste des petits ruminants virus are described. The protocols can be used to carry out quality-controlled vaccine efficacy and pathogenesis studies under experimental conditions.

Experimental infection of alpine goats with a Moroccan strain of peste des petits ruminants virus (PPRV).

Peste des petits ruminants virus (PPRV) recently caused a serious outbreak of disease in Moroccan sheep and goats. Alpine goats were highly susceptible to PPRV with mortality rates approaching 100%, as opposed to local breeds of sheep which were less susceptible to the disease. The relative susceptibility of alpine goats was investigated through an experimental infection study with the Moroccan strain of PPRV. Severe clinical signs were observed in the alpine goats with virus being excreted through ocular, nasal and oral routes. No difference in the severity of the disease in goats was observed with different inoculation routes and transmission of the virus by direct contact was confirmed. This study confirmed the susceptibility of the alpine goat to PPRV infection and describes a challenge protocol that effectively and consistently reproduced severe clinical signs of PPR in experimentally infected goats.