OCCURRENCE AND RELEVANCE OFMYCOPLASMA STURNIIN FREE-RANGING CORVIDS IN GERMANY

Abstract

Several Mycoplasma spp. are well-known pathogens in poultry. In birds of prey, White Storks ( Ciconia ciconia ), and some waterfowl (Anatidae, Pelecanidae) species, mycoplasmas occur commonly and seem to be apathogenic or commensal and most likely belong to the physiologic microbial flora of the respiratory tract. In other bird species, such as Common Nightingales ( Luscinia megarhynchos ) and tits (Paridae), Mycoplasma spp. are absent in healthy birds. In corvids, the prevalence and role of Mycoplasma spp. in disease remains unclear. In previous studies, Mycoplasma sturni was detected in diseased corvids; however, those studies included only a limited sample size or preselected individuals. We collected tracheal swabs of 97 free-ranging Corvidae, including 68 randomly selected individuals from hunting bags and 29 birds that had been admitted to a veterinary clinic. Tracheal swabs were examined for Mycoplasma spp. using culture and genus-specific PCR. If Mycoplasma spp. were detected, the species were identified by sequencing the 16S ribosomal (r) RNA gene and 16-23S rRNA intergenic transcribed spacer region. Five of 68 (7%) of the hunted birds and nine of 29 (31%) of the birds admitted to the veterinary clinic were PCR positive. In 13 of 14 PCR-positive samples, mycoplasmas were cultured and M. sturni was the only mycoplasmal species identified. None of the positive corvids from the hunting bags had clinical signs, whereas five of nine birds admitted to the veterinary clinic showed apathy, lameness, injuries, or fractures, which may not be associated with mycoplasmal infections. These data support the notion that M. sturni is the Mycoplasma sp. most frequently found in corvids, though its prevalence and ability to cause disease may involve interaction with other aspects of bird health.

Absence of Mycoplasma spp. in nightingales (Luscinia megarhynchos) and blue (Cyanistes caeruleus) and great tits (Parus major) in Germany and its potential implication for evolutionary studies in birds

“…The results of the present study indicate that the investigated populations of passerine species (nightingales, great and blue tits) do not show any mycoplasmas as part of their physiological respiratory flora. However, prior studies indicated that some songbirds do show detectable mycoplasmas in their respiratory tract, as there were 7% of healthy free-ranging corvids tested positive for Mycoplasma sturni (Ziegler et al 2017). As all birds under study were tested negative for mycoplasmas and the prevalence of Mycoplasma spp.…”

“…In contrast, no mycoplasmas were found in healthy individuals belonging to other bird species e.g., psittacines or passerines (Lierz and Hafez 2009;Deem et al 2012). In corvids, mycoplasmas were isolated from diseased birds (Pennycott et al 2005), but also from 7% of clinically healthy individuals (Ziegler et al 2017). Therefore, corvids seem to occupy an intermediate position, so that mycoplasmas may play a role in respiratory disease.…”

“…In 30 cases, the bird's age was not documented. DNA extraction of all swabs was performed as described by Ziegler et al (2017). All samples (n = 172) were screened via Mycoplasma genus-specific PCR (target sequence: 16S rRNA gene) as described by van Kuppeveld et al (1992) modified by Lierz et al (2007).…”

Occurrence and relevance of Mycoplasma spp. in free-ranging pheasants from northwestern Germany

“…may represent facultative pathogens causing similar alterations when causing disease. Mycoplasma sturni is responsible for severe conjunctivitis in various bird species (Forsyth et al 1996;Frasca et al 1997;Ley et al 1998;Wellehan et al 2001), but was also found in healthy corvids (Ziegler et al 2017). Furthermore, corvids suffering from stressful conditions showed a higher prevalence (31%) than healthy individuals (7%).…”

Identification and differentiation of avian Mycoplasma species using MALDI-TOF MS

“…may occur, the detection of mycoplasmas does not necessarily lead to the diagnosis of a mycoplasmosis, and species differentiation is required. 15,20 Infections with avian mycoplasmas can be detected indirectly by a serologic assay or directly by methods including conventional isolation and identification as well as genusspecific or species-specific PCRs. 11 However, many laboratory tests are only available and validated for pathogenic avian mycoplasmas in poultry.…”