Husbandry practices for cats infected with feline leukemia virus or feline immunodeficiency virus.

Cats that are persistently infected with FeLV or feline immunodeficiency virus but are not manifesting clinical signs of disease are at risk for developing a wide variety of immunosuppressive, degenerative, or neoplastic diseases. Infected cats should be isolated to prevent transmission of virus to healthy cats, and to protect infected cats from exposure to pathogens that can cause life-threatening secondary infections. Iatrogenic transmission of virus from infected cats in isolation to healthy cats may be reduced by strict adherence to handling, sanitation, and disinfection procedures. Husbandry practices that may delay the complications of infection include regular vaccination, provision of high-quality diets, reduction of stress, control of endoparasites and ectoparasites, and early and aggressive treatment of clinical signs of disease.

Otitis externa. A disease of multifactorial etiology.

Dogs and cats with long-standing otitis externa pose a difficult diagnostic challenge for the veterinarian, because chronically affected ears usually have the same appearance regardless of the underlying cause(s). In patients with chronic otitis externa, the disease is often caused by different combinations of primary, predisposing, and perpetuating factors. The unique therapeutic needs of each patient may be determined by careful interpretation of historical and physical findings, which should be supported by ancillary diagnostic tests.

Toxoplasmosis.

Infection with T. gondii can have devastating effects on the development of the unborn human fetus. As veterinarians or physicians, we should be able to accurately assess the true risk of exposure of a person to meat-borne tissue cysts or to oocysts based on the age, health, roaming and feeding habits of their cats, and the occupational or recreational activities of the individual. When time precludes an in-depth discussion of preventive measures to decrease exposure to the parasite, the whole client education program can be neatly summarized in the admonition, "When pregnant, wash your hands thoroughly before eating or touching your face, and cook your meat thoroughly." In this way, the risk of exposure to toxoplasmosis and all other meat- or soil-borne diseases is greatly reduced.

Left hepatic vein attenuation for treatment of patent ductus venosus in a dog.

Patent ductus venosus was identified in a young dog. Surgical attenuation of the anomalous vessel was performed by partial ligation of the left hepatic vein. Clinical signs resolved after surgery, and laboratory values returned to normal. Jejunal venous portography, performed 8 weeks after surgery, revealed complete occlusion of the patent ductus venosus, with normal portal vasculature to the right and central divisions of the liver. Atrophy of the left hepatic division resulted.

Feline viral respiratory disease. The carrier state, vaccination, and control.

A thorough understanding of the epizootiology of FCV and FRTV is critical when implementing control measures in premises with enzootic URD. Failure to properly segregate cats, reduce fomite contamination, or implement a vaccination schedule most suited to that population will undoubtedly allow perpetuation of disease. Several questions remain unanswered about URD in cats. Following several years of widespread routine vaccination, what is the prevalence of the carrier state in vaccinated cats? What are the immunologic mechanisms responsible for the development of the latent FRTV carrier state and the variable level of virus excretion in FCV carriers? Why do some cats terminate primary infections with these viruses without entering a chronic carrier phase? Could immunomodulating agents be used to terminate the carrier state in persistently infected animals?

Zoonotic diseases of cats.

As veterinarians, our responsibilities do not end with the care of our patients. The welfare of our clients and their families depends on our ability to detect and control potentially zoonotic diseases in their pets. Because some of these zoonoses can have devastating effects on the development of the unborn fetus or on family health in general, discussion about these diseases between veterinarian and client is often emotionally charged. Under such circumstances, the offering of inaccurate and erroneous information by the veterinarian can have drastic consequences. It is likely that other zoonotic diseases of domestic pets will be identified in the future, especially those that can cause opportunistic infections in debilitated and immunodeficient persons. In the meantime, the potential hazards of cat ownership can be significantly reduced through an increased understanding of feline diseases and an improved level of health care for our feline patients.

Feline infectious peritonitis. An immune-mediated coronaviral vasculitis.

Mainly through studies inducing experimental infection of susceptible cats, significant advances have recently been made in our understanding of the pathogenesis of FIP. Much of this knowledge should not presently be directly extrapolated to field cases of FIP, because the route of infection and challenge dose and strain of virus may be significantly different. Advances in the prevention and treatment of FIP will depend greatly on clarification of the exact nature of the several coronaviruses affecting cats and the role of cell-mediated immunity in resistance to FIPV.

Serum gamma-glutamyl transpeptidase activity in healthy cats and cats with induced hepatic disease.

Activities of serum gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) were determined in healthy cats and in cats before and after treatment: common bile duct ligation, carbon tetrachloride administration, sham surgery, or anesthesia only. Significant (P less than 0.01) increases in serum GGT, ALP, and ALT occurred in cats with ligated bile ducts. Significant (P less than 0.01) increases in serum ALT occurred in carbon tetrachloride-treated cats. Increases of serum GGT, ALP, or ALT were not observed in cats subjected to sham surgery or anesthesia only compared with these cats' baseline values and values in healthy cats. Tissue GGT activity was measured in liver, renal cortex, jejunal mucosa, and bile ducts. There was a 1.5-fold increase in GGT activity in livers of cats with ligated bile ducts, compared with that in livers of healthy cats.

Gastrointestinal disorders of the cat.

Several areas of feline gastroenterology deserve critical attention in the near future. For example, as compared with the dog, little is known about the various causes of malabsorptive disease in the cat. So frequently, intestinal biopsy samples reveal nothing more than intestinal thickening with fibrosis and nonspecific mild cellular infiltration, and the inciting cause is never determined. It is, perhaps, wrong to be critical about the use of the bark of Berberis vulgaris and the root of Rheum in modern feline gastroenterology, since most of us occasionally use unconventional therapies. It has been rumored that I have been known to advocate the daily addition of a tablespoon of pumpkin-pie filling to the food of cats suffering from recurrent constipation and acquired megacolon. The rumors are true, and colonic evacuation is sometimes promoted with the use of this unusual bulking agent after traditional drug therapy has failed. We all have our weaknesses!

Hypothyroid myopathy in two dogs.

Biopsy specimens of skeletal muscle and peripheral nerve from two dogs with primary hypothyroidism but without clinical neuromuscular disease were studied with histological, histochemical and morphometric techniques. The most prominent change in skeletal muscle was variation in fiber size associated with a pronounced reduction in mean diameter of type II fibers. Type II fiber loss was apparent in the specimen from one dog. No histological or morphometric differences were noted in nerves from either dog compared with an age-matched control. The myopathic findings suggest a preferential metabolic defect in type II muscle fibers.

Subclinical myopathy associated with hyperadrenocorticism in the dog.

One of seven dogs with clinical signs of hyperadrenocorticism had clinical evidence of neuromuscular disorder. Clinical diagnosis of hyperadrenocorticism was confirmed by plasma cortisol concentrations before and after adrenocorticotrophin hormone and dexamethasone administration. Electromyographic studies showed bizarre, high frequency discharges in all dogs. Examination of muscle biopsies taken from the biceps femoris muscle from each dog revealed mild degenerative changes of fiber size variation, focal necrosis and fiber splitting. Ragged red fibers were prominent and appeared to be related to mitochondrial aggregates. Significant (P less than 0.05) type 1 and 2 fiber atrophy was found in all dogs. Fiber grouping was present in four dogs. Studies of fascicular biopsies of the peroneal nerve showed thinly myelinated fibers, onion-bulb formation, segmental demyelination and short intercalated internodes. These findings suggested a glucocorticoid-related myopathy in hyperadrenocorticism that also may have a neurogenic component.

Filaroides hirthi in a dog: fatal hyperinfection suggestive of autoinfection.

Progressive dyspnea in a dog began 1 month after it had been hit by a car. Radiographs revealed diffuse interstitial and alveolar pneumonia. Large numbers of embryonated eggs were observed in bronchial washings; and many small nematodes, later identified as Filaroides hirthi, were found in the fine needle aspirates of pulmonary tissue. Numerous nematode larvae were demonstrated on fecal flotation. The severe hyperinfection strongly suggested autoinfection, probably associated with depressed immunologic competence due to chronic stress.