76 (101)

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bleed. In some studies, FIV infection has been found to be a predisposing factor (15-30% of cases were FIV-positive)^2S. This was not true for FeLV infection (less than 6% of cases were FeLV-positive)²⁹. Lesions are similar to those seen in plasma celi gingivitis in many HIV patients²³. Failure of the immunological barrier of the orał cavity may be induced by certain viruses (e.g. FIV and Calicivirus) and pathogenic periodontal bacteria (e.g. Porphyromonas spp.), often present in huge numbers in periodontal disease. This failure could explain some features of the pathophysiology of plasma celi stomatitis. It has recently been reported that odontoclastic resorptions were morę common in FIV-positive cats³⁰.

Plasma celi pododermatitis is rare ³¹ and usually starts with marked pain in one or morę metacarpal or metatarsal footpads. These swollen footpads are soft and painful in the centre, causing lameness. With time, swellings, which ulcerate and bleed at the slightest touch, develop on one or morę metacarpal or metatarsal footpads and/or digits (fig. 7 : 23). The older the lesions are, the morę likely they are to develop secondary infection. Cats are sometimes affected systemically with pyrexia, listlessness, anorexia, anaemia and peripheral lymphadenopathy. Plasma celi stomatitis is sometimes also present. In one recent study of 18 cases of plasma celi pododermatitis, nearly 50% of cats were FIV-positive ³². In another study, lesions of plasma celi pododermatitis were found in 6 out of 9 cats with natural FIV infection ³³. FIV-immunoreactive cells have been found in the inflammatory infiltrate of a cat from which it was possible to take frozen sections.

Plasma celi chondrilis is extremely rare^{34 36} and is characterised by an often symmetrical, painful swelling of the pinnae, followed by reduction in size and healing (Fig. 7 : 24). In the initial phase, systemie signs (pyrexia etc...) are seen. Some of these cases have been found to be FeLV or FIV-positive ^35,36.

When there is plasma celi infiltration, irrespective of where it occurs in the body, biochemistry profiles often reveal hypergammaglobulinaemia. Histopathology initially reveals, an almost pure plasmacytic infiltration, with Russell bodies, followed later by a mixed cellular infiltrate (lymphocytes, neutrophils and eosinophils)³².

Opportunistic skin infections associated with T celi immunosuppression

There are no studies proving the existence of opportunistic skin infections associated with FeLV and FIV ^21>22. Only a few isolated cases of association between retroviruses and reputedly opportunistic infections in man have been published. However, some studies do attempt to show an association between certain clinical manifestations and status of one or other of the retroviruses³⁷. The development of opportunistic skin infections is related to an already advanced cellular immunosuppression. The medical prognosis for a particular condition is no morę severe in a cat with FIV and / or FeLV infection than in a cat without these infections, in that there are no signs of immunodeficiency connected with derangement of cell-mediated immunity²².

Mycoses make up the main group of opportunistic infections linked to FeLV or FIV (Table 7:1) ³⁷'⁴¹. Few studies on the fungal skin flora of cats carrying retroviruses have been conducted. It is universally true, however, that morę fungi (genera and species) are carried by cats with a positive retroviral status^3S. The incidence of Microsporum canis carriage varies in different studies from 10% - 75%. These substantial differences arise because of the diverse naturę of the populations tested ^3W9. No study has shown that superficial and deep (subcutaneous and systemie) mycoses (Table 7:1) are morę common in retrovirus-positive cats. The very most that can be said is that they are clinically morę severe and richer in fungal elements, and that they resolve morę slowly or even incompletely. This applies even to superficial mycoses. Although a causal relationship between retroviral status and subcutaneous and systemie mycoses has not been proven, once these mycoses have been diagnosed, testing for retroviruses should be routine⁴⁰.

Multicentric bacterial paronychia is very common in retrovirus-positive cats, especially those that are FIV-positive ³¹. Stained smears taken from the digital region show several species of intracellular and extracellular bacteria (cocci and bacilli). The prognosis is often guarded.

Deep bacterial skin infections are regularly encountered in retrovirus-positive cats and are characterised clinically by multiple nodules or true deep abscesses with draining traets. They can be found in various locations⁴⁰. Histopathology points towards a particular aetiological grouping (Table 7:1). Identification of the causal bacteria is not always easy and often reąuires the help of specialist laboratories⁴⁰.

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