Prevalence of cerebral palsy in Quebec: alternative approaches.

AIM: To provide an estimate of the period prevalence of cerebral palsy (CP) in the province of Quebec. METHODS: Children with CP were identified from three consecutive birth cohorts (1999-2001) from the Quebec CP Registry, covering 6 of the 17 administrative health regions of the province. Two inferential approaches were applied for period prevalence estimation, frequentist and bayesian. RESULTS: 228 children were identified with CP. Using a frequentist approach, the overall prevalence of CP was 1.84 per 1,000 children aged 9-11 years living in those areas in 2010 (95% CI 1.60-2.08). Using a bayesian approach taking into account the uncertainty about the registry's sensitivity in capturing all cases, the overall prevalence is higher at 2.30 per 1,000 children with a 95% CI (1.99-2.65). CONCLUSION: Using a bayesian approach to adjust for the registry's known high specificity and lower sensitivity, the prevalence estimate is in concordance with worldwide estimates and estimates using administrative databases in western Canadian provinces. Future studies are needed to validate the diagnosis of CP within administrative databases and to evaluate possible regional trends across Canada in both prevalence and health service utilization, which may highlight disparities in healthcare delivery.

Molecular cloning of the bovine viral diarrhea virus genomic RNA.

The genomic RNA from Bovine Viral Diarrhea Virus (BVD) was cloned in E. coli. The complete sequence has been obtained and the genomic organization has been deduced. Some of the BVD specific cDNA have been expressed in bacteria, eucaryotic cells and in vitro. We suggest that BVDV belongs to a new family different from Togaviridae and Flaviviridae.

Molecular cloning of bovine viral diarrhea viral sequences.

Bovine viral diarrhea virus (BVDV) genomic RNA was identified as a 12.5-kb single-stranded RNA molecule in both infected bovine embryonic kidney cells (BEK-1) and partially purified virions. BVD virion RNA was partially purified and used as a template for cDNA synthesis. BVDV-specific cDNA sequences were molecularly cloned and shown to hybridize to infected cell RNA but not to uninfected cell RNA or DNA. A single RNA species of 12.5 kb, representing the viral RNA genome, was detected in infected cells. A preliminary map of the BVDV specific cDNA clones was constructed and five major, nonoverlapping families were observed, accounting for approximately one-half of the viral genome.

Interferon response in colostrum-deprived newborn calves infected with bovine rotavirus: its possible role in the control of the pathogenicity.

Colostrum-deprived newborn calves were experimentally infected with cell-culture rotavirus. A similar process of infection was observed when the animals were inoculated immediately after birth or at the age of three days, with a corresponding delay in the onset of virus excretion and interferon production in the later case. With high doses of virus, interferon was produced very early and no symptoms were observed. With lower doses of virus, interferon production was delayed and preceded by a severe but transient diarrhoea. In all cases, several waves of interferon production were observed. Our data indicate that interferon plays an important role in the control of viral diseases in calves and in their natural recovery.

Propagation of bovine rotavirus by young dogs.

Ten young dogs were experimentally infected twice with different isolates of bovine rotavirus and 2 uninfected dogs were kept in contact with them. None of the animals developed diarrhoea, but all of them excreted rotavirus in their faeces over a period of up to 10 days after each inoculation, as shown by counterimmunoelectro-osmophoresis and virus isolation. Dogs may thus play a role in the epizootiology of rotavirus diarrhoea in calves. Seroconversion occurred in 6 of the 10 infected dogs but in neither of the 2 contact controls.

[Attempt at the experimental reproduction of rotavirus diarrhea in newborn calves deprived of colostrum]. / Tentative de reproduction expérimentale de la diarrhée à rotavirus chez des veaux nouveau-nés privés de colostrum.

Colostrum-deprived newborn calves were orally inoculated with different doses of cell-culture bovine rotavirus or with bacterium-free filtrates of calf stools containing rotavirus. None of the animals that received high doses of cell-culture rotavirus developed diarrhoea or any other clinical sign, although all of them excreted virus for several days and produced specific antibodies; calves inoculated with lower doses of cell-culture virus or with stool filtrates showed a transient diarrhoea 48 h after inoculation. Such paradoxical results might be due to a phenomenon of interference, as bovine rotavirus is susceptible to interferon. In experimental conditions, rotavirus produces only a mild and transient diarrhoea: this contrasts with the situation observed in farms, where that virus may provoke important problems. In association with the virus itself, numerous other factors such as the environmental conditions or the response of the calf to the infection also play a role in the evolution of the disease.

Propagation of bovine rotavirus by cats and dogs.

SPF cats were experimentally infected orally with bovine rotavirus. All of them excreted virus over a period of at least two weeks after inoculation. Seroconversion was observed after one week for all the animals, but it did not stop viral excretion or prevent further excretion of the same or another rotavirus strain given later. Cats or dogs kept in the same cage as inoculated animals became infected and excreted virus, but seroconversion was not observed in these contact animals. None of the animals developed diarrhoea during the experiment. Cats are thus able to multiply bovine rotavirus, and transmission of this virus occurs between cats or between dogs and cats. Therefore, cats, like dogs, may play a role in the epizootiology of rotavirus infection in calves.

Susceptibility of bovine rotavirus to interferon. Brief report.

Using the plaque assay or the CPE test (cytopathogenic effect), we investigated the action of human, simian (rhesus), bovine and murine interferons on bovine rotavirus adapted to grow on established Rhesus monkey kidney cell line (MA 104) or Georgia Bovine Kidney cell line (GBK). Except for the murine interferon we used, which had no antiviral effect at all, the different interferons tested were clearly active.