Congenital toxoplasmosis in Abyssinian cats

Two of three litter-mate kittens born to an Abyssinian cat died of acute toxoplasmosis. Toxoplasma gondii was found in histologic sections of both kittens and this was confirmed by immunoperoxidase staining.     

Pathogenesis of acute toxoplasmosis in specific-pathogen-free cats

Systemic toxoplasmosis was produced in specific-pathogen-free cats by intravenous inoculation with Toxoplasma gondii tachyzoites. Infectious organisms were recovered from all tissues studied, but the number of organisms recovered from liver, lungs and spleen was 10-fold to 10,000-fold higher than from heart and brain. The occurrence and severity of Toxoplasma-induced lesions correlated with the number of infectious organisms recovered from the various tissues. In nonlymphoid tissues, the Toxoplasma-associated lesions consisted of multifocal necrosis, usually with demonstrable organisms. Lesions in the spleen and mesenteric lymph nodes consisted of reticuloendothelial and lymphoid hyperplasia, with few demonstrable organisms. Pneumonitis was severe and sometimes fatal in the early stages of systemic toxoplasmosis. Light- and electron-microscopic studies showed that the earliest lung lesions were randomly distributed infiltrates of neutrophils, eosinophils, and mononuclear cells into alveolar walls. Later lesions were diffuse alveolar necrosis, pneumocytic hyperplasia, and extensive fibrinocellular exudates in alveoli. Tachyzoites were present in cytoplasmic vacuoles of fibroblasts, macrophages, type I and II pneumocytes, bronchiolar epithelial cells, bronchiolar smooth muscle cells, endothelial cells, neutrophils, and eosinophils, and circulating monocytes. Replication of organisms was found in all parasitized cell types except neutrophils and eosinophils.     

Chronic rhinitis in cats

Chronic rhinitis is a common and important problem in cats potentially resulting from a number of intranasal or systemic disorders. Idiopathic chronic rhinosinusitis and nasal neoplasia are the most common causes of chronic nasal disease in cats. For most cats with chronic rhinitis, diagnostic imaging, endoscopic studies, and nasal biopsy will be required to establish a diagnosis. A discussion of some of the more common causes of chronic nasal disease is presented.     

Fatal toxoplasmosis in sand cats (Felis margarita)

The sand cat (Felis margarita) is a small-sized felid occurring in the United Arab Emirates (UAE). The sand cat captive-breeding program at the Breeding Centre for Endangered Arabian Wildlife in Sharjah, UAE, has until recently been severely compromised by very high newborn mortality rates. Two different pairs of sand cats gave birth, respectively, to one and two litters (with a total of eight kittens) between 1999 and 2006. Seven out of eight kittens died between the third and 21st wk of life. Toxoplasmosis was confirmed as the cause of death in these two litters. Adult cats had high antibody titers to Toxoplasma gondii before pregnancy, suggesting that maternal immunity did not protect the kittens against infection with T. gondii and that maternal immunity might not have prevented transplacental transmission of the parasite. This observation contrasts with what is seen in domestic cats. To date, this is the first report on confirmed fatal toxoplasmosis and prevalence of T. gondii in sand cats.     

Chronic gastroenterocolitis in nine cats.

Lesions of a chronic gastroenterocolitis were found in 9 cats of the Persian breed that were euthanized after a prolonged period of bloody diarrhea. Gross lesions consisted of gastrointestinal edema with prominent Payer's patches, multiple grayish nodules, and a few irregular erosions within the colonic mucosa. Microscopically, the changes were composed of degeneration, necrosis, and proliferation of gastric glandular epithelium, dilated intestinal crypts with lymphoplasmacytic cell infiltration of the lamina propria, and in 1 cat, severe transmural necrosis of the colon. With the Giemsa stain, spiral-shaped organisms in the gastrointestinal lumen and intracellularly in the gastric and the colonic epithelium were observed. These organisms could not be cultured. Although the role of these spiral-shaped organisms was not determined, other agents that could explain the disorder were not found.     

Acute toxoplasmosis following renal transplantation in three cats and a dog.

Three cats and 1 dog that had undergone renal transplantation because of end-stage renal disease were examined because of complications 3 to 6 weeks after surgery. One cat died prior to treatment of the complications; Toxoplasma cysts were found in sections of the renal allograft, and Toxoplasma tachyzoites were found in other organs. The other 2 cats and the dog died despite treatment, and protozoal cysts, as well as tachyzoites, were identified in other organs but not within the allografts, suggesting that reactivation of latent infection following immunosuppression was the most likely cause of disseminated toxoplasmosis. These cases illustrate that toxoplasmosis can be a fatal complication in renal transplant recipients. We currently recommend that feline and canine donors and recipients undergo serologic testing for toxoplasmosis prior to surgery. In addition, we suggest that seropositive donors not be used for seronegative recipients and that seropositive recipients and that seropositive recipients be monitored closely after surgery for clinical signs of toxoplasmosis.     

Antemortem diagnosis and treatment of toxoplasmosis in two cats on cyclosporin therapy

Clinical toxoplasmosis was diagnosed antemortem in two cats being treated with therapeutic doses of cyclosporin. The diagnosis was made by detecting tachyzoites on cytological examination of bronchoalveolar lavage fluid from one case and pleural effusion from the other. Despite early diagnosis and aggressive treatment in both cases, only one cat survived. Reactivation of latent Toxoplasma gondii infection secondary to cyclosporin-induced immunosuppression was considered likely in both cases. The presence of respiratory signs in cats treated with cyclosporin should alert clinicians to the possibility of clinical toxoplasmosis. Consideration should be given to determining the serostatus of cats to T gondii prior to use of drugs which are potent inhibitors of cell mediated immunity, such as cyclosporin. Two cases of feline toxoplasmosis are presented.     

Mitogen and antigen-specific induction of lymphoblast transformation in cats with subclinical toxoplasmosis.

Lymphoblast transformation in whole blood was assessed by 3H-thymidine incorporation after stimulation by concanavalin A and Toxoplasma gondii secretory and intracellular antigens in samples from cats with experimentally induced toxoplasmosis. Toxoplasma gondii-specific immunoglobulin M, immunoglobulin G, and circulating antigens were also measured throughout the study period. Lymphocytes from all cats were responsive to concanavalin A pre- and post-inoculation with T. gondii. Suppression of mitogen-stimulated lymphoblast transformation during the course of infection was not observed. Both the secretory and intracellular antigens stimulated lymphoblast transformation in many cats from Week 2 to Week 52 post-inoculation. Lymphoblast transformation was stimulated more frequently by intracellular antigens (66.25%) than by secretory antigens (48.75%). Lymphoblast transformation was not induced by T. gondii antigens in any cat prior to appearance of T. gondii-specific antibodies in serum or during the oocyst shedding period. Cats with persistent antigenemia had the most consistent lymphoblast transformation results induced by T. gondii-specific antigens.     

Chronic diaphragmatic hernia in 34 dogs and 16 cats

Medical records of 34 dogs and 16 cats undergoing surgical repair of diaphragmatic hernia of >2 weeks' duration were reviewed, and long-term follow-up information was obtained. The most common clinical signs were dyspnea and vomiting; however, many of the animals were presented for nonspecific signs such as anorexia, lethargy, and weight loss. Thoracic radiographs revealed evidence of diaphragmatic hernia in only 66% of the animals, and additional imaging tests were often needed to confirm the diagnosis. Thirty-six hernias were repaired through a midline laparotomy; 14 required a median sternotomy combined with a laparotomy. In 14 animals, division of mature adhesions of the lungs or diaphragm to the herniated organs was necessary to permit reduction of the hernia. Fourteen animals required resection of portions of the lungs, liver, or intestine. All hernias were sutured primarily without the use of tissue flaps or mesh implants. Twenty-one of the animals developed transient complications in the postoperative period; the most common of these was pneumothorax. The mortality rate was 14%. Thirty-four (79%) of the animals that were discharged from the hospital had complete resolution of clinical signs, and none developed evidence of recurrent diaphragmatic hernia during the follow-up period. Nine were lost to follow-up.     

Chronic ingestion of high concentrations of cholecalciferol in cats

OBJECTIVE: To determine whether ingestion of 63 times the recommended amount of vitamin D3 (cholecalciferol) results in renal calcification or damage in cats. ANIMALS: 20 four-month-old kittens, 17 queens, and 20 kittens born to these queens. PROCEDURE: 4-month-old kittens and queens were given a purified diet with 846 microg of cholecalciferol/kg of diet (high vitamin D3 diet) or 118 microg of cholecalciferol/kg of diet (control diet) for 18 months. Kittens born to queens were weaned onto the same diet given to dams. RESULTS: There were no apparent adverse effects of the high vitamin D3 diet. Plasma cholecalciferol and 25-hydroxycholecalciferol (25-OHD3) concentrations of queens and 4-month-old kittens given the high vitamin D3 diet significantly increased with time. At 6 months, plasma cholecalciferol concentrations in these kittens and queens were 140.0+/-7.3 nmol/L and 423.6+/-26.6 nmol/L, respectively (10 times initial values). Corresponding 25-OHD3 concentration in queens was 587.5+/-59.4 nmol/L (2.5-fold increase over initial values). At 3 months of age, kittens born to queens given the high vitamin D3 diet had an increase in serum BUN and calcium concentrations and a decrease in RBC and serum total protein, albumin, and hemoglobin concentrations. By 18 months, these kittens had an increase in plasma cholecalciferol (276.0+/-22.2 nmol/L) and 25-OHD3 (1,071.9+/-115.3 nmol/L) concentrations. However, all indices of renal function and the appearance of renal tissue on histologic evaluation were normal. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicate that cats are resistant to cholecalciferol toxicosis when the diet is otherwise complete and balanced.     

Effect of primary phase feline immunodeficiency virus infection on cats with chronic toxoplasmosis.

The effect of primary phase feline immunodeficiency virus (FIV) infection on clinical signs, hematological values, Toxoplasma gondii oocyst shedding, T. gondii-specific serology, T. gondii-specific cell-mediated immune responses, non-specific cell-mediated immune responses, and lymphocyte subpopulations from cats with experimentally induced chronic toxoplasmosis was studied. No significant clinical or hematologic abnormalities were noted following inoculation with FIV. T. gondii-specific IgM was significantly increased, concanavalin A, T. gondii tachyzoite antigen and T. gondii secretory antigen induction of lymphocyte transformation were significantly suppressed, and CD4+ cell numbers were significantly decreased following inoculation with FIV. The changes were attributed to FIV effects on the immune system and resultant activated toxoplasmosis.     

Chronic abscesses in cats associated with an organism resembling Mycoplasma

Three cats were admitted to the Ontario Veterinary College with chronic nonhealing abscesses which had not responded to a variety of local and systemic treatments.

Smears made from the purulent exudate and stained with Wright's, Giemsa's and Gram's stains did not reveal the presence of any bacteria, yeast or fungal hyphae. Bacteria could not be cultured aerobically or anaerobically but organisms resembling mycoplasmas were cultured in two cases. All cats responded to tetracycline therapy.