The nomenclatural type by monotypy (Murray, 1984a) is the class Mollicutes, which consists of very small prokaryotes that are devoid of cell walls. Electron microscopic evidence for the absence of a cell wall was mandatory for describing novel species of mollicutes until very recently. Genes encoding the pathways for peptidoglycan biosynthesis are absent from the genomes of more than 15 species that have been annotated to date. Some species do possess an extracellular glycocalyx. The absence of a cell wall confers such mechanical plasticity that most mollicutes are readily filterable through 450 nm pores and many species have some cells in their populations that are able to pass through 220 nm or even 100 nm filters. However, they may vary in shape from coccoid to flask-shaped cells or helical filaments that reflect flexible cytoskeletal elements.

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Phylum XVI. Tenericutes Murray 1984a, 356 VP (Effective publication: Murray 1984b, 33.)

Mycoplasma infection of ducks and geese

We determined the prevalence of mycoplasma infection in breeding mallard (Anas platyrhynchos) and canvasback (Aythya valisineria) hens and their broods from the central United States (1988 to 1990); and wintering American black duck (Anas rubripes) and mallard hens from the eastern United States (1990 to 1993). Mycoplasmas were isolated by culturing tracheal swabs from 656 live birds and tissue samples from 112 dead waterfowl. Nine (18%) of 51 mycoplasma isolates were identified as Mycoplasma anatis; M. anatis was recovered from four mallards, a black duck, and a gadwall (Anas strepera) duckling. Nineteen (37%) of 51 mycoplasma isolates were identified as Mycoplasma cloacale; these isolates were obtained from mallard, canvasback, and black duck adults, and from a mallard duckling. Additional unspeciated mycoplasmas were isolated from mallards, black ducks, and one canvasback.

The occurrence of mycoplasmas in selected wild north american waterfowl

Overview of Avian Neurology and Neurological Diseases

We inoculated game-farm mallard (Anas platyrhynchos) eggs and 1-day-old birds with Mycoplasma anatis to determine its effect on hatching success and growth rates of ducklings Inoculations of eggs reduced hatching success, hatchling size, and duckling growth rates, compared to controls Intratracheal inoculations of 1-day-old birds did not affect growth rates Hatchlings and 1-day-old ducklings grew much slower for the first 7 to 10 days when raised at 17 to 19 C, compared to controls raised at 30 to 35 C The effect of cold stress on growth was greater than the effect of M anatis infection; we found no synergistic effects between cold stress and M anatis infection

https://bioone.org/journals/Journal-of-Wildlife-Diseases/volume-31/issue-2/0090-3558-31.2.172/EFFECTS-OF-MYCOPLASMA-ANATIS-AND-COLD-STRESS-ON-HATCHING-SUCCESS/10.7589/0090-3558-31.2.172.pdf

Effects of mycoplasma anatis and cold stress on hatching success and growth of mallard ducklings

Summary

A disease associated with central nervous system signs was observed in two duck flocks, each consisting of 6000 three-week-old ducklings, a week after their arrival at the receiving farms.



The clinical signs included leg weakness, dyspnoea, diarrhoea, and in many cases disturbance of equilibrium, retrograde movement, torticollis and twisting of the neck. Pathological and histopathological examinations revealed lympho-histiocytic meningitis and cerebroventriculitis, airsacculitis with moderate amounts of fibrinous exudate, bronchitis associated with formation of lymphoid follicles, focal or interstitial pneumonia, in some cases with fibrinous serositis, interstitial catarrh and splenomegaly. Large numbers of mycoplasmas were seen by electron microscopy and were isolated from the affected meninges and pericardium.



Other diseases were excluded by laboratory examinations. The isolates were identified as Mycoplasma anatis. The pathogenicity and immunogenicity of the strain were investigated in an infection experiment in ducks. Although during this experiment no disease associated with clinical signs or deaths occurred, birds infected into the airsacs or intracranially exhibited pathological lesions similar to, but milder than, those seen in the field outbreak. No immune response was detectable by the serological and cellular tests applied. The pathological significance of M. anatis infection in ducks merits further study.



Zusammenfassung

Ausbruch einer Mycoplasma anatis-Infektion in Verbindung mit nervosen Symptomen bei Entenbestanden in Massenhaltung



In zwei Bestanden mit je 6000 drei Wochen alten Entenkuken wurde eine Erkrankung verbunden mit zentralnervosen Symptomen beobachtet. Zum Symptomenbild gehorten Beinschwache, Atemnot, Durchfall, in vielen Fallen Gleichgewichtsstorung, retrogarde Bewegung, Torticollis und Verdrehung des Halses. Bei der pathologischen und histopathologischen Untersuchung wurden eine lymphohistiozytare Meningitis und Cerebroventriculitis, eine Entzundung der Luftsacke mit geringen Mengen fibrinosen Exsudates, eine fokale oder interstitielle Pneumonie (teilweise mit fibrinoser Serositis), ein interstitieller Katarrh und eine Splenomegalie diagnostiziert. Eine grose Anzahl von Mycoplasmen wurde elektronenmikroskopisch nachgewiesen und aus den affektierten Meningen und dem Perikardium isoliert. Die Isolate wurden als Mycoplasma anatis identifiziert und andere Krankheitsursachen durch Laboruntersuchungen ausgeschlossen.



Die Pathogenitat und die immunogenen Eigenschaften des isolierten Stammes wurden in einem Infektionsversuch an gesunden Tieren gepruft. Wahrend des Versuchszeitraumes konnten weder Erkrankungen mit sichtbaren klinischen Anzeichen noch Todesfalle beobachtet werden. Allerdings wurden bei den uber die Luftsacke oder intrakranial infizierten Tieren pathologische Veranderungen festgestellt, die den Befunden der Feldausbruche ahnelten, jedoch milder in der Auspragung waren. Sowohl mit den serologischen als auch den zellularen Testmethoden konnte eine Immunantwort nicht nachgewiesen werden.

Györgyi Takács

Papers

An outbreak of Mycoplasma anatis infection associated with nervous symptoms in large-scale duck flocks.