Safety and Efficacy of the Avirulent Mycoplasma gallisepticum Strain K5054 as a Live Vaccine in Poultry

Abstract

A Mycoplasma gallisepticum (MG) isolate from an atypically mild outbreak in turkey breeders was found to be similar to house finch isolates by DNA analyses. A preliminary study in turkeys showed that this isolate (K5054) caused very mild lesions and protected turkeys against subsequent challenge with a virulent MG strain. In this study, K5054 was further evaluated as a potential vaccine strain in commercial layer-type chickens and turkeys. The safety of K5054 was evaluated by aerosol challenge followed by evaluation of gross and histopathologic lesions as well as serologic reactions and isolation of MG from the trachea and air sacs. Infection of chickens (trial 1) and turkeys (trial 2) with K5054 resulted in little evidence of MG lesions. There was weak seroconversion, and K5054 was consistently reisolated from the tracheas of chickens and turkeys. The efficacy of K5054 as a vaccine was evaluated by aerosol challenge of vaccinated chickens (trial 3) and turkeys (trial 4) with virulent R strain. There was evidence of protection from lesions associated with MG.

Use of molecular diversity of Mycoplasma gallisepticum by gene-targeted sequencing (GTS) and random amplified polymorphic DNA (RAPD) analysis for epidemiological studies

“…The identification of turkey isolate K5054TK01 as identical to the house finch isolates verified our earlier reports of a naturally occurring house-finch-like isolate in a turkey breeder flock (Ferguson et al, 2003). This isolate has been characterized by its low pathogenicity in turkeys and chickens, and its potential as a live M. gallisepticum vaccine for turkeys and chickens has been evaluated (Ferguson et al, 2004).…”

Re-Exposure of Captive House Finches That Recovered From Mycoplasma Gallisepticum Infection

“…Although there is extensive information available on MG infection and immunity in chickens and turkeys (Ley, 2003), little information is available for house finches. In recent studies, it was demonstrated that house finches develop some immunity after being exposed to MG (Roberts et al, 2001;Farmer at al., 2002;Ferguson et al, 2003;Kollias et al, 2004).…”

“…House finches reinoculated 7 to 14 mo after an initial infection were able to mount an immune response and clear infection much more rapidly than naive birds exposed to MG, a result that has also been observed in chickens re-exposed to MG. (Yagihashi and Tajima, 1986). Ferguson et al (2003) demonstrated that turkeys infected with MG strain K5054 of lower virulence but very similar to the house finch strain developed some immunity and subsequently exhibited resistance when challenged with a virulent MG strain (R strain).…”

Immune responses to vaccination and infection with Mycoplasma gallisepticum in turkeys

“…A number of studies have examined the lesions induced by this pathogen in the respiratory tract of chickens or turkeys, and have described diffuse infiltration of the tracheal mucosa with mononuclear cells and varying numbers of small to large focal aggregations of lymphocytes, resulting in moderate to extensive thickening of the tracheal mucosa accompanied by epithelial degeneration and metaplasia with or without luminal exudation (Nunoya et al, 1987;Papazisi et al, 2002;Kleven et al, 2004;Sanei et al, 2007;Shil et al, 2011;Wijesurendra et al, 2015). Airsacculitis is also a prominent gross feature of the disease and the gross appearance of airsacculitis has been used extensively to assess the severity of disease caused by infection with M. gallisepticum in chickens and turkeys (Lin & Kleven, 1982;Ferguson et al, 2004;Kleven et al, 2004;Sanei et al, 2007). Recently the histopathological changes in the infraorbital sinuses and the air sacs of turkeys infected with an aerosol of a culture of M. gallisepticum have been characterized and these studies revealed the presence of focal lymphocytic aggregations within the sinus mucosa and air sacs (Wijesurendra et al, 2015).…”