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RETROVIRIDAE. Part I- RETROVIRUSES. PETER H. RUSSELL, BVSc, PhD, FRCPath, MRCVS Department of Pathology and Infectious Diseases, The Royal Veterinary College, Royal College Street, London NW1 OTU. E-mail Web site. Objective Students should be able to:.
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RETROVIRIDAE. Part I- RETROVIRUSES PETER H. RUSSELL, BVSc, PhD, FRCPath, MRCVS Department of Pathology and Infectious Diseases, The Royal Veterinary College, Royal College Street, London NW1 OTU. E-mailWeb site
ObjectiveStudents should be able to: • define the importance of reverse transcriptase in replication and chromosomal integration. • explain subgroup, endogenous viruses, oncogenes and transformation, how lability leads to either horizontal transmission by close contact/blood or vertical transmission. • describe the clinical signs of FeLV, the diagnostic ELISA test for FeLV and test and removal schemes. • describe in outline the pathogenesis and control of Bovine Leukosis virus and sheep Pulmonary Adenomatosis
Classification of Retroviridae the genera include these veterinary viruses:
Physicochemical properties: The virus only survives for a few hours outside the host. Small amounts of virus are excreted by the host and infection requires either close contact, e.g. mutual grooming, blood transfer or vertical transmission (see later)
Detection Because leukaemia viruses cause no cytopathic effect in tissue culture they have been detected by EM or by IIF .
Cell tropism in vivo: They grow in rapidly-dividing cells eg bone marrow.
FELINE LEUKAEMIA VIRUS (FeLV) FeLV is one causative agent of feline lymphosarcoma and leukaemia, which are the most important and common tumours of cats. The same tumours sometimes occur without FeLV, particularly in cats aged over 7 years.
FELINE LEUKAEMIA VIRUS (FeLV) Pathogenesis:
FELINE LEUKAEMIA VIRUS (FeLV) Clinical signs:
FELINE LEUKAEMIA VIRUS (FeLV) Epidemiology:
FELINE LEUKAEMIA VIRUS (FeLV) Diagnosis of FeLV:
FELINE LEUKAEMIA VIRUS (FeLV) Control:
SHEEP PULMONARY ADENOMATOSIS (SPA) Virus: Retrovirus particles can be seen by EM in the tumour cells of affected sheep. The virus cannot be grown in culture.
SHEEP PULMONARY ADENOMATOSIS (SPA) Diagnosis:No serological test nor virus isolation is possible. Clinical symptoms. Nasal fluid discharges when the sheep is up-ended (the wheelbarrow test). At post mortem the tumour is fawn-grey in colour but may be obscured by secondary infection with oedema and/or pneumonia.
BOVINE LEUKOSIS VIRUS (BLV) Notifiable disease.