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Feline infectious diseases–a collection of interesting cases (Proceedings)

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Nov 01, 2010

Infectious diseases can often be insidious in their clinical presentation. Case studies will be used to highlight some interesting infectious diseases that can affect the feline patient.

Lungworm infection

Causative agent: Aelurostrongylus abstrusus

Transmission: Predation of paratenic hosts (mice, voles and possibly birds) that ingest infected snails or slugs (intermediate hosts); Cats are the principle hosts.

Geographic distribution: Worldwide

Pathogenesis: Cats are the principle hosts of this worm. Adult worms live in the bronchioles. Larvae are deposited in the bronchioles and coughed up, swallowed and shed in the feces. Snails and slugs are the intermediate hosts.

Risk factors: Outdoor cats with exposure to snails and slugs and paratenic hosts

Clinical findings: Related to inflammatory reactions to the parasites. "Asthma" like signs – coughing, wheezing, overt respiratory distress. Thoracic radiographs may show diffuse interstitial nodules; peribronchial and alveolar patterns may also be present.

Diagnosis: Detection of larvae in airway washes or lung aspirates or Baermann fecal

Treatment: Fenbendazole 25-50 mg/kg PO q 24 hours for 10-14 days; Ivermectin 400 ug/kg SQ; bronchodilators and glucocorticoids may be needed to address the inflammation.

Public health considerations: None.

Things to remember: A treatable cause of "asthma"

Mycoplasma polyarthritis

Causative agent: Mycoplasma spp. (M. gatae, M. felis)

Transmission: Cat to cat - suspect initial respiratory, conjunctival or urogenital infection with systemic spread.

Geographic distribution: Worldwide

Risk factors: Large cat population (cattery), exposure to other cats, immunosuppression, stress

Clinical findings: Fever, hyperesthesia, difficulty walking, joint effusion, joint pain.

Diagnosis: Identification of the organism by culture or PCR in joint fluid; suppurative joint effusion

Treatment: Doxycycline 5 mg/kg PO q 12h; Prednisolone may also be needed due to the polyarthritis (2.5 – 5 mg/ cat every 12-24h). Must treat for an extended period of time.

Public health considerations: Not considered to be a major public health risk.

Things to remember: The organisms may become intracellular, resulting in chronic persistent infection. These organisms may also stimulate chronic immune-mediated disease.

Toxoplasma gondii -neurologic involvement

Causative agent: Toxoplasma gondii, an obligate intracellular coccidian protozoan parasite

Transmission: Infection acquired by ingestion of infective oocysts or tissue cysts.

Geographic distribution: Worldwide; higher seroprevalence in warm, moist, or tropical climates.

Risk factors: Immunosuppression from infections such as FeLV, FIV, or FIP; Glucocorticoid therapy or antitumor chemotherapy; post renal transplantation; ingestion of raw meat; outdoor cats hunting prey (birds, rodents).

Clinical findings: Anorexia, lethargy, fever, weight loss, vomiting, diarrhea, respiratory difficulties, icterus, abdominal effusion, ocular inflammation, blindness, anisocoria, seizures, behavioral changes, incoordination, circling, twitching, tremors, ataxia, paresis, paralysis, muscle pain/weakness, tetraparesis. Clinical signs may be sudden or slow in onset.

Diagnosis: Serology – IgM, IgG titers on serum and CSF; CSF analysis – high leukocyte count (mononuclear cells and neutrophils), elevated protein; organism detection rare.