Feline immunodeficiency virus (FIV) belongs to the family Retroviridae, genus Lentivirus, and is transmitted mainly through bites and mating. The initial stages of the infection may pass unobserved by the animal’s owner, while the later stages may be accompanied by the development of various pathologies, of which the most common are opportunistic infections, chronic ulcero-proliferative stomatitis, neoplasms (such as squamous cell carcinoma, lymphoid tumours – mainly B-cell lymphomas unlike the lymphomas induced by FeLV which are often T-cell lymphomas – myeloid neoplasms, and sarcomas), ocular diseases such as uveitis and chorioretinitis, neurological disorders, anaemia, leukopenia, renal failure and endocrine disorders such as hyperthyroidism and diabetes mellitus.
There is not a specific dermatological condition associated with FIV infection, but cats with this disease are predisposed to the development of skin infections following the state of immunodepression induced by the virus. Bacterial folliculitis, dermatophytosis, demodectic mange and notoedric mange are the most common complications and often present with more extensive and more severe clinical pictures than those seen in FIV-negative cats. Many cats with FIV infection have been found to have a form of bacterial paronychia, affecting several paws, not associated with other skin lesions. Furthermore, it has been observed that, compared to FIV-negative cats, FIV-positive felines have greater skin colonisation by yeasts of the genus Malassezia.
Other skin problems that can be found in cats infected by FIV are subcutaneous abscesses, poxvirus infections and nodular dermatitides caused by deep bacterial infections (infections by atypical mycobacteria, nocardiosis, actinomycetosis, botryomycosis) or fungal infections (cryptococcosis, histoplasmosis, phaeohyphomycosis, pythiosis). In these cases, histological examination of the nodular lesions and cultures of the deep tissues, with an antiobiogram, are essential in order to reach the correct diagnosis.
A possible association between FIV infection and the development of plasma cell pododermatitis or plasma cell chondritis of the pinna has been suggested but not yet been demonstrated. The pathogenic role played by FIV in these diseases could be related to the capacity of the virus to induce activation and differentiation of B lymphocytes. It should be noted that recent studies do not seem to confirm a previously suggested association between FIV infection and the development of papillomavirus infections.
At present there are no curative or preventive treatments for FIV infection, although the subcutaneous administration of feline interferon (1 MU/Kg every 24 hours for 5 days in three cycles repeated on days 0, 14 and 60) has been demonstrated to be useful in improving cutaneous signs and reducing mortality in cats co-infected with FIV and feline leukaemia virus. Seropositivity does not necessarily imply a reduced or absent response to specific treatments for secondary infections even though it has been observed that recovery, particularly from dermatophytosis or demodicosis, may be very slow or incomplete and the prognosis tends, therefore, to be uncertain.
Suggested readings
- De Mari K, Maynard L, Sanquer A et al. Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats. Journal of Veterinary Internal Medicine 2004, 18:477-82.
- Guaguère E. Viral dermatoses. In: A practical guide to feline dermatology, Guaguère E, Prelaud P eds, Blackwell Scienceedn, FranceP. A practical guide to feline dermatology, Oxford, 2000:7.1-7.11
- Munday JS, Witham AI. Frequent detection of papillomavirus DNA in clinically normal skin of cats infected and noninfected with feline immunodeficiency virus. Veterinary Dermatology 2010, 21:307-10.
- Neel JA, Tarigo J, Tater KC, Grindem CB. Deep and superficial skin scrapings from a feline immunodeficiency virus-positive cat. Veterinary Clinical Pathology 2007, 36:101-4.
- Reche A Jr, Daniel AG, Lazaro Strauss TC et al. Cutaneous mycoplora and CD4:CD8 ratio of cats infected with feline immunodeficiency virus. Journal of Feline Medicine and Surgery 2010, 12: 355-8.