Differential Serologic Response to Mycoplasma Ovipneumoniae and Mycoplasma Arginini in Lambs Affected with Chronic Respiratory Disease

Abstract

Abstract. An enzyme-linked immunoabsorbent assay (ELISA) was used to evaluate the levels of antibodies to Mycoplasma ovipneumoniae and M. arginini in lambs with chronic respiratory disease. Sera were obtained from lambs in several flocks at various stages of the clinical disease and tested with sodium dodecyl sulfate (SDS)-treated M. ovipneumoniae and M. arginini whole cells and a crude capsular extract of M. ovipneumoniae as the antigens. There were low levels of antibody to M. ovipneumoniae in flocks sampled at the early stages of infection, whereas increased levels of antibody were present in lambs from flocks that had apparently recovered from the clinical disease. Slowly rising titers of circulating antibodies to M. ovipneumoniae were confirmed by sequential bleeding of lambs during the course of the clinical disease. However, antibody levels of M. arginini were more likely to increase earlier in the disease process. There was significant cross-reactivity between the 2 SDS-treated antigens in both the ELISA test and western immunoblotting. In contrast, the crude capsular extract was specific for detecting antibodies to M. ovipneumoniae.Mycoplasma ovipneumoniae (MO) is one of the most commonly isolated microorganisms from sheep with respiratory disease worldwide. 4 Recently in this laboratory, this microorganism and M. arginini (MA) have been routinely recovered from young lambs with a respiratory disease that has been termed the ''coughing syndrome.'' The condition is associated with a severe paroxysmal cough, leading to rectal prolapses. This syndrome is widespread in the midwestern states of the USA, with morbidity and severity variable among flocks. The disease is chronic and persists for several weeks in most affected lambs. There is some evidence that the extended persistence of the MO organism in the respiratory tract of these lambs and the chronic nature of the disease may be due to failure of the immune system to generate protective immunity. 10 Reasons for that failure are not known, but marked variation in the MO organisms isolated from sheep 7 and expression of a polysaccharide capsule by the organisms are recognized. 11 Because of its simplicity the enzyme-linked immunosorbent assay (ELISA) has been extensively used in detecting antibodies to Mycoplasma species. However, concerns exist about its specificity because of crossreactions among several Mycoplasma species. 3 Several attempts have been made to overcome such specificity problems by using different methods of antigen preparation. 6,12 Solubilized whole cell antigens of MO have been used, and cross-reactivity problems were noted with these preparations. 5 Consequently, a crude capsular material was extracted from MO for use as a diagnostic antigen, and the specificity of this reagent was confirmed in ELISA and western immunoblotting procedures. Humoral response to MO could be distinguished from humoral response to MA when measured with crude capsular material extracted from the MO organisms. Levels of antibodies to MO and MA antigens in th...

Inoculation of lactating ewes by the intramammary route with Mycoplasma agalactiae: comparative pathogenicity of six field strains

“…Regarding the serological responses of ewes following inoculation with various strains of M. agalactiae, high levels of antibodies have been previously reported to be closely associated with induction of clinical signs and high levels of infection, as in other Mycoplasma infections such as M. ovipneumoniae in adult sheep [13] or M. agalactiae in lambs [19]. In the present study, in spite of comparable levels of infection, great individual variations were observed and some ewes remained seronegative while others developed very high titres; thus the highest titres (>1000 units) were obtained with the supposed "asymptomatic" strain 9523, while 2 ewes remained negative with the reference virulent strain P89.…”

Presence of mycoplasmas in the respiratory system of small ruminants managed under extensive production system

“…or through movement associated with trade (2). The asymptomatic presence of M. ovipneumoniae could also predispose goats to pneumonia caused by other organisms, as was previously observed in sheep (16). The lack of positive samples from adult goats could be explained by the capacity of some adult goats to clear the infection or at least inhibit bacterial growth (17).…”

Experimental infection of specific-pathogen-free domestic lambs withMycoplasma ovipneumoniaecauses asymptomatic colonization of the upper airways that is resistant to antibiotic treatment

“…In vitro studies have shown that M. ovipneumoniae specific antibodies can have protective functions by mediating opsonization and phagocytosis of the Mycoplasma [35]. Likewise, Niang et al [36] found increased levels of M. ovipneumoniae-reactive antibodies in lambs that had recovered from the clinical M. ovipneumoniae infection. In our study, lambs had no detectable M. ovipneumoniae specific antibodies prior to experimental inoculation but developed a significant, stable antibody response within two weeks after infection, confirming previous studies that have tracked humoral responses to M. ovipneumoniae [37].…”