Oral trichomonosis: Description and severity of lesions in birds in Spain

Abstract

Avian trichomonosis is a parasitic disease caused by the flagellated protozoan Trichomonas gallinae. Columbiformes are the reservoir host of the parasite, with high levels of infection, but also other domestic and wild birds from a variety of orders are susceptible to the infection and development of gross lesions. A total of 94 clinical cases diagnosed of trichomonosis were selected for the categorization of their lesions at the upper digestive tract. The affected birds were classified into three different categories (mild, moderate and severe) based on the size, the depth and the location of the lesions. Mild grade is found in small and superficial lesions far from the oropharyngeal opening; moderate grade for bigger and deeper lesions, and severe grade for very big and deep lesions that impede swallowing or affect the skull. This revision of lesions will help to understand the pathologic and epidemiological information about avian trichomonosis. Furthermore, it will be helpful for the evaluation, prognosis and possible treatments among veterinarians and related professionals.

Investigation of Trichomonas gallinae in passerines

“…The formation of yellow-white nodules and plaques in the oral cavity are characteristics of avian trichomonosis but are not pathognomonic lesions. Capillariasis, salmonellosis, hypovitaminosis, candidiosis, poxvirus infection, aspergillosis, might display similar gross appearance (Alkharigy et al, 2018;Martínez-Herrero et al, 2020).…”

Captive Breeding and Trichomonas gallinae Alter the Oral Microbiome of Bonelli’s Eagle Chicks

“…In this study, only three animals displayed severe lesions of trichomonosis, according to the above-mentioned criteria [ 27 ]. The analyses of alfa and beta diversity did not show differences between birds severely affected by the parasite and those with mild or no oropharyngeal lesions, although a trend towards a lower beta diversity was observed in animals with severe lesions ( p = 0.079).…”

“…Oropharyngeal sterile swabs were aseptically taken from each chick and then kept frozen at − 20 °C until DNA extraction. A visual inspection of the oropharyngeal cavity was carried out to detect the presence of macroscopic lesions, and when found, they were classified as mild, moderate or severe, according to criteria previously published [ 27 ], such as the size of the lesion in relation to the tracheal opening, the depth (superficial or deep) and the location of the lesions (distance from the tracheal opening).…”

Trichomonas gallinae infections in the naïve host Montifringilla nivalis subsp. nivalis

“…The flagellated protozoa Trichomonas gallinae (Rivolta 1878) is known since the end of the nineteenth century as a pathogen of birds (Stabler 1947). Infections with T. gallinae are referred to as trichomonosis typically causing yellow lesions located in the oral cavity, eyes, skull, pharynx, oesophagus and crop (Martínez-Herrero et al 2020). The severity of the disease ranges from no clinical signs to multifocal lesions with ulcerations and/or systemic infections.…”

“…On the other hand, distinct strains of T. gallinae differ in their virulence (Sansano-Maestre et al 2009). Sequencing of three genetic markers, the 18S rRNA gene, the ITS1/5.8S rRNA/ITS2 region, and the Fe-hydrogenase gene, has been mainly used for molecular characterisation (Gaspar da Silva et al 2007;Sansano-Maestre et al 2009;Lawson et al 2011;Ganas et al 2014;McBurney et al 2015;Chavatte et al 2019;Rijks et al 2019;Martínez-Herrero et al 2020). Depending on the marker and whether single locus or multi-locus approaches are used, differentiation down to the species or even strain level is possible.…”