Toxoplasma pneumonia in a cat with incongruous serological test results

Abstract

A 12‐year‐old neutered male domestic short‐haired cat was presented for rapid breathing, lethargy of two weeks duration and chronic weight loss. A diagnosis of toxoplasma‐induced pneumonia was made based on clinical signs, laboratory data, radiology, immunoglobulin M (IgM) serology and isolation of the organism from a lung aspirate. A passive haemagglutination test to measure immunoglobulin G (IgG) levels against toxoplasma was negative. The reliability of agglutination tests, to accurately diagnose an acute toxoplasma infection is questioned. In acute infections the use of an enzyme‐linked immunosorbent assay for IgM may be more specific.

Lower Respiratory Tract Infections in Cats

“…The lung appears to be a target organ in both primary and reactivated toxoplasmosis in cats. 3,26,[120][121][122][123][124][125][126][127][128][129][130][131][132] The risk of infection is increased with immunosuppression and there is an increasing number of reports of pulmonary toxoplasmosis in cats that have been treated with ciclosporin (Fig 8). 128,130,132 Diagnosis Diagnosis of LRTIs due to T gondii is very difficult.…”

“…127 Another cat with a 2week history of respiratory signs and tachypnoea and dyspnoea on pres entation, due to pulmonary toxoplasmosis, survived 3 months after being given clindamycin as the sole treatment, before dying (no necropsy performed). 123 However, two cats treated solely with clindamycin died. 126,128 Three cats treated with clindamycin and trimethoprim/ sulphonamide 129,132 or sulfamethox azole 128 also died, as did one treated with clindamycin and doxycycline.…”

“…One study reported it to be efficacious; 139 however, the selection criteria for that study included response to appropriate treatment or histopathological confirmation and the only case with definite histological confirmation died without treatment. Pooling several papers 123,124,[126][127][128][129]132 and one unpublished case (K Briscoe, personal communication, Fig 8) of confirmed pulmonary toxoplasmosis, only one cat with mild clinical signs (but significant pulmonary pathology) responded well to clindamycin treatment alone. 127 Another cat with a 2week history of respiratory signs and tachypnoea and dyspnoea on pres entation, due to pulmonary toxoplasmosis, survived 3 months after being given clindamycin as the sole treatment, before dying (no necropsy performed).…”

Respiratory and Thoracic Medicine

“…60 In a study of 100 cases with histologically confirmed toxoplasmosis, 76.7% of 86 lung tissue samples assessed had organisms present, and in the 36 cats considered to have generalized toxoplasmosis, 26 had predominantly pulmonary lesions. 219,235 Diffuse interstitial to alveolar patterns are typically described, 14,219,235 but a bronchial influence is also possible 14 (Figure 30-20). 17 Diagnosis is achieved by recognition of Toxoplasma tachyzoites, which can be found in BAL fluid 14 or FNA of affected lung tissue.…”