Verification of accuracy of qPCR method for intravital diagnostics of Macrorhabdus ornithogaster in avian droppings

Lenka Vrbasova; Dobromila Molinkova; Petr Linhart; Zdenek Knotek

doi:10.17221/85/2022-VETMED

Verification of accuracy of qPCR method for intravital diagnostics of Macrorhabdus ornithogaster in avian droppings

Vet Med (Praha). 2023 Feb 22;68(2):69-74. doi: 10.17221/85/2022-VETMED. eCollection 2023 Feb.

Authors

Lenka Vrbasova¹, Dobromila Molinkova², Petr Linhart³, Zdenek Knotek¹

Affiliations

¹ Avian and Exotic Animal Clinic, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic.
² Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic.
³ Department of Animal Protection and Welfare and Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic.

Abstract

The objective of this study was to verify the accuracy of the quantitative PCR (qPCR) method for in vivo detection of Macrorhabdus ornithogaster. A total of 100 faecal and gastric mucosa samples from avian cadavers were investigated, using cytological and qPCR techniques (budgerigars, Fischer's lovebirds, red-crowned parakeets, scarlet-chested parrots, eastern rosellas, domestic canaries, zebra finches, white Java sparrow). Using qPCR, the probability of detecting positive samples of droppings was significantly higher than in the faecal smear microscopy (P < 0.01). Cytology detected the presence of Macrorhabdus ornithogaster in 34 faecal samples, whereas qPCR detected 54 positive samples. In all 46 qPCR negative faecal samples, gastric smear qPCR was performed and also yielded negative results. Gastric smear qPCR was also performed in 20 cadavers where faecal qPCR has detected the presence of Macrorhabdus ornithogaster and in all samples confirmed the positive result. This verifies the accuracy of faecal sample qPCR for intravital diagnostics. Overall, the faecal qPCR technique appears to be extremely reliable, as it made it possible to detect all infected individuals, including those with negative stool or gastric cytology.

Keywords: cytology; macrorhabdosis; passerines; psittacines.

Grants and funding

Received financial support from the internal grant agency at VETUNI Brno (No. IGA/103/2022FVL – qPCR technique for laboratory diagnostics, incidence monitoring and therapy control of Macrorhabdus ornithogaster).