Novel characteristics identified in two cases of feline cowpox virus infection

Breheny, Craig R; Fox, Victoria; Tamborini, Alice; O’Halloran, Conor; Robertson, Elise; Cazzini, Paola; Birn-Jeffery, Daniela; Henkin, Julia; Schwarz, Tobias; Scase, Tim; Powell, Roger; Gunn-Moore, Danièlle

A number of different poxviruses can infect both people and domestic animals; with cowpox being the best described and most commonly encountered poxvirus infection of cats. Cowpox virus (CPxV) is a member of Orthopoxviridae family and is endemic in Northern Europe and western areas of the Soviet Union. 1 The usual route of infection is via skin inoculation from infected rodent bites, typically voles, or rarely via oronasal infection. 2 Reflective of this transmission route, skin lesions are commonly found on the head, neck and forelimbs. However, systemic illness such as pyrexia, anorexia, lethargy and/or pneumonia can occur during the viraemic phase and is usually associated with immune dysfunction and death. 3, 4 It is important that clinicians recognise the signs of potential CPxV infection and perform appropriate diagnostics early. A significant factor contributing to the prognosis of CPxV infection in cats is the speed at which appropriate therapy is instituted, so rapid recognition is crucial. Cytological analysis of the affected organs can be misleading, with the secondarily dysplastic cells having the potential to mimic neoplasma. Instead, electron microscopy, virus isolation and PCR of tissues (including skin scabs, bronchoalveolar or pleural fluid, or pulmonary aspirates) are the easiest ways to confirm the diagnosis. 5 Serum assays (including virus neutralisation, haemagglutination inhibition, complement fixation and ELISA) can be utilised to detect a humoral response to Novel characteristics identified in two cases of feline cowpox virus infection orthopoxvirus, although a rising titre is required to support active infection. 4 Treatment includes broad-spectrum antibiotics to control secondary bacterial infection and recombinant feline interferon omega (rFeIFN-ω) to modulate the immune response. Antiviral drugs, such as famciclovir, commonly used for the treatment of feline herpesvirus (FeHV-1) disease in cats, 6 could also be considered; however, their efficacy against CPxV is unknown.