Introduction

Classification

Taxonomy

• Malignant catarrhal fever (MCF) virus (MCFV) group contains at least 10 members.
  • Commonly MCF is caused by two viruses:
    • Alcelaphine herpevirus 1 (A1HV-1)
    • Ovine herpesvirus 2 (OvHV-2).
  • If MCF occurs due to other agents, the spectrum and severity of lesions may differ.
• Family: herpesviridae.
• Genus: macavirus.
• Species: alcelaphine herpevirus 1 and ovine herpesvirus 2.

Active Forms

Clinical Effects

Epidemiology

Pathological effects

• The pathological effects are poorly understood but gammaherpes viruses have a tropism for T and B lymphocytes.
• MCF is believed to occur following virus entry into the upper respiratory tract which results in a cell mediated response (virus infected cytotoxic T lymphocytes or NK cells) which causes tissue damage.
• MCF has a long incubation period of 3-10 weeks, but can be as long as 9 months.
• Following this clinical signs (peracure or chronic) appear including:
  • Fever.
  • Ocular and nasal discharge (may also include conjunctivitis and encrustation of the muzzle) .
  • Enlarged lymph nodes.
  • Mucosal lesions.
  • Neurological signs (muscle tremors, incoordination, head pressing).
  • Death within 7 days (deer can die suddenly without clinical signs).

Control

Control via animal

• Separation of cattle and deer from sheep/lambs/wildebeest.
• Access to contaminated fomites should be avoided.
• Culling of sheep which are identified as being infected with the virus.
• Cattle are dead-end hosts and do not need to be culled.
• Early weaning of sheep can result in a OvHV-1 free herd.
• Stress reduction.

Vaccination

• None available.

Diagnosis

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Li H, Cunha C W, Taus N S & Knowles D P (2014) Malignant catarrhal fever: inching toward understanding. Annu Rev Anim Biosci 2, 209-33 PubMed.
• O'Toole D & Li H (2014) The pathology of malignant catarrhal fever, with an emphasis on bovine herpesvirus 2. Vet Pathol 51 (2), 437-52 PubMed.
• Li H, Cunha C W & Taus N S (2011) Malignant catarrhal fever: understanding molecular diagnostics in context of epidemiology. Int J Mol Sci 12 (10), 6881-93 PubMed.
• Russell G C, Stewart J P & Haig D M (2009) Malignant catarrhal fever: a review. Vet J 179 (3), 324-35 PubMed.

Organisation(s)

• OIE: http://www.oie.int.