Pathogenicity of Mycoplasma synoviae in Broiler Chickens

Abstract

Six isolates of Mycoplasma synoviae, identified as WVU 1853, K1968, K1858, 92D8034, F10-2AS, and FMT, were compared for pathogenicity in broiler chickens. Specific-pathogen-free chickens were inoculated, in two groups of 20, with each isolate by footpad or eyedrop inoculation at 1 day of age and were examined at necropsy 7, 14, 28, and 42 days postinoculation. Specimens were taken for histopathology, culture, polymerase chain reaction assay, and hemagglutination-inhibition serology. Isolates were grouped according to pathogenicity on the basis of differences in lesion development and tissue distribution in the respiratory system, other viscera, and the skeletal system. K1968 (pathogenic) induced lesions in all sites examined in both the footpad and eyedrop inoculation groups. It was detected in all sites following footpad inoculation and in all sites except viscera following eyedrop inoculation. WVU 1853, K1858, and 92D8034 (moderately pathogenic) induced lesions and were detected in all sites following footpad inoculation. With eyedrop inoculation, lesions were identified only in upper and lower respiratory sites, and organisms were detected only in upper respiratory sites. F10-2AS (moderately pathogenic) was similar; however, footpad inoculation failed to induce visceral lesions or permit organism detection in any site. F10-2AS was detected in upper and lower respiratory tissues following eyedrop inoculation. FMT (mildly pathogenic) induced only upper respiratory lesions when either footpad or eyedrop inoculation was used, and detection was restricted to upper respiratory sites following eyedrop inoculation. These results are useful in comparative evaluations of the virulence of other M. synoviae isolates and form a basis for characterization of virulence factors of M. synoviae.

Genetic variation in sialidase and linkage to N-acetylneuraminate catabolism in Mycoplasma synoviae

“…Passages 33 and 126 of the FMT strain [3] only generated approximately 8 kb amplicons, suggesting the deletion of a portion(s) of the locus. Homologs of nanA, nanE, nanI, nagA, nagB, and nagC were present in each strain in the same orientations as in strain 53 ( Figure 1B).…”

“…The FMT strain, originally isolated from chicken trachea, induced minor respiratory lesions following experimental infection [3]; stocks FMT33 and FMT126 were derived from serial in vitro passages of FMT. Strain K3344 was isolated during an outbreak of apparent reproductive disease in a breeder flock in 1992, but was demonstrated to produce respiratory lesions during experimental infections [48].…”

“…Lesions from infected birds involved synovial membranes, bursa of Fabricius, liver, kidney, and the lower respiratory tract in breeders [50]. Strain WVU1853 T has been most commonly reported to cause airsacculitis and synovitis [2], however, experimental infection studies indicated that this strain is capable of systemic spread and the generation of lesions in multiple tissues [3,51]. Strains K4907A and K5395B were isolated from clinically normal chickens, and are not suspected to cause significant lesions.…”

“…Mycoplasma synoviae is a major avian pathogen associated with osteoarthritis, synovitis, and respiratory tract lesions in gallinaceous birds [1,2,3]. Infection can produce disease that ranges from subclinical to severe, and clinical outcome can be influenced by co-infection with other agents [4,5,6,7,8].…”

Características clínicas e anatomo-histopatologicas da infecção experimental mista por Orthoreovirus aviario e Mycoplasma synoviae em frangos de corte

“…Na cápsula ainda observou-se leve hiperplasia das células sinoviais. Este padrão lesional pode ser observado tanto na infecção pelo ARV (Ni & Kemp 1995, Vasconcelos et al 2001a, quanto pelo MS (Lockaby et al 1998). É importante considerar que o ARV e o MS causam uma doença progressiva com caráter crônico, levando a alterações graves das estruturas da articulação.…”