Canine angiostrongylosis is now considered as an emerging condition in Belgium. The gold standard for the diagnosis is based on the detection of first-stage larvae by Baermann faecal analysis. However, the imperfect sensitivity is the main disadvantage of this test. Alternative methods including serological or molecular assays have been developed to improve diagnosis. Detection of circulating antigens seems to enable diagnosis before patency; however, sensitivity in naturally-infected dogs with negative Baermann analysis has not been documented. PCR on bronchoalveolar lavage fluid (BALF) has recently been reported as valuable tool and helpful in dogs with negative Baermann analysis.

Comparative usefulness of faecal or serological tests and BALF analysis has not been investigated in naturally-infected dogs. The aim of this study was to report and compare results of the rapid test detecting circulating antigens, Baermann analysis and PCR on BALF in a small series of dogs with angiostrongylosis.

Dogs with suspected angiostrongylosis based on clinical findings, for which results of three different diagnostic methods were available, were retrospectively included. The three methods were PCR, performed on BALF, the rapid blood test (AngioDetect^TM©, Idexx Laboratories) and Baermann analysis, performed on three faecal samples.

Seven dogs were selected. Owners reported cough and dyspnoea of variable severity from 2 weeks to 2 months' of duration. PCR on BALF was positive in all dogs while the rapid test was negative in 4 dogs and uninterpretable in another one. Among the 4 dogs with negative rapid test, Baermann analysis was also negative in 3 dogs. Bronchoscopy and PCR on BALF were thus essential for diagnosis in 3 dogs, which presented moderate-to-severe clinical signs from 2 to 4 weeks. If PCR on BALF is considered as gold standard, relative sensitivities of the rapid test and Baermann analysis would be of 29% and 42%, respectively.

In conclusion, even though Baermann analysis and the rapid test should be used as first-line tools because of their availability, cost-effectiveness and non-invasiveness, they might be of lower sensitivity than BALF PCR analysis in early cases. Based on this small descriptive series, bronchoscopy and PCR on BALF may be considered in clinically-suspected dogs in which both rapid test and Baermann analysis are negative. Further studies including ELISA assays for antigens or antibodies are warranted to help select the most appropriate diagnostic tests in canine angiostrongylosis.

Disclosures

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