Mycoplasma agalactiae, an Etiological Agent of Contagious Agalactia in Small Ruminants: A Review

Abstract

Mycoplasma agalactiae is one of the causal agents of classical contagious agalactia (CA), a serious, economically important but neglected enzootic disease of small ruminants. It occurs in many parts of the world and most notably in the Mediterranean Basin. Following the infection common complications are septicaemia, mastitis, arthritis, pleurisy, pneumonia, and keratoconjunctivitis. Primary or tentative diagnosis of the organism is based upon clinical signs. Various serological tests, namely, growth precipitation, immunofluorescence, complement fixation test, haemagglutination inhibition, agglutination, immunodiffusion, enzyme immunoassays, immunoelectrophoresis, blotting techniques, and others, are available. Molecular tools seem to be much more sensitive, specific, and faster and help to differentiate various strains. The real-time PCR, multiplex PCR, quantitative PCR, PCR-RFLP, MLST, and gene probes, complementary to segments of chromosomal DNA or 16S ribosomal RNA (rRNA), have strengthened the diagnosis of M. agalactiae. Both live attenuated and adjuvant (alum precipitated or saponified) inactivated vaccines are available with greater use of inactivated ones due to lack of side effects. The present review discusses the etiology, epidemiology, pathogenesis, and clinical signs of contagious agalactia in small ruminants along with trends and advances in its diagnosis, treatment, vaccination, prevention, and control strategies that will help in countering this disease.

Mycoplasma agalactiae Secretion of β-(1→6)-Glucan, a Rare Polysaccharide in Prokaryotes, Is Governed by High-Frequency Phase Variation

“…Phenotypic switching, as observed for ␤-(1¡6)-glucan phase variation, can be a real asset when the environment imposes strong selection (49). During the course of infection, M. agalactiae is disseminated from the primary site of infection (respiratory tract mucosa, small intestine, or the mammary gland alveoli, depending on the routes of transmission) to different vital organs by the bloodstream (50). Switching off ␤-(1¡6)-glucan allows the generation of a M. agalactiae subpopulation that is less susceptible to the bactericidal activity of goat serum and to the lytic action of the complement (Fig.…”

Novel Mycoplasma Agalactiae with new P30 Protein Pattern by Major Change in 17 Amino Acids

“…Adaptation of M. agalactiae isolates to new environment needed the time and when adapted to laboratory conditions, these grow easily in commonly used media for mycoplasma growth freshly (Srivastava., 1982, Kumar et al, 2014.…”

Mycoplasmosis in Small Ruminants in India: A Review

“…They are mostly commensals but can cause heavy morbidity and mortality under favourable circumstances (Tigga et al, 2014). This mycoplasma class comprises of four orders having several families and more than 160 species affecting animals and humans (DaMassa, 1996;Nicholas, 2002;Kumar et al, 2014 (Nicholas 2002;Kumar et al, 2011b;Kumar et al, 2014;Chakraborty et al, 2014).…”

“…Common mycoplasmal diseases include contagious caprine pleuropneumonia, contagious agalactia, pneumonias, besides arthritis, mastitis, seminal vesiculitis, ampullitis, epididymitis, orchitis, urethritis, conjunctivitis and meningitis either alone or as classical syndromes (Nayak & Bhowmik, 1990b;DaMassa, 1996;Thiaucourt & Bolske, 1996;Kumar et al, 2014). These diseases produce a conglomerate of clinical signs including respiratory signs, genito-urogenital signs, mastitis, arthritis, conjunctivitis and nervous signs thus making clinical diagnosis difficult (Priya et al, 2008;Ravishankar et al, 2011;Awati & Chavhan, 2013;Chakraborty et al, 2014).…”