Insights on Mycoplasma gallisepticum and Mycoplasma synoviae infection in poultry: a systematic review

Avian mycoplasmosis mainly caused by Mycoplasma gallisepticum and M. synoviae is an economically important disease of poultry industry. It causes huge economic losses in terms of decrease in weight gain, feed conversion efficiency, egg production, hatchability; increase in embryo mortality, carcass condemnation, prophylaxis and treatment cost in broiler, layer and breeder flocks. The disease is caused by four major pathogenic mycoplasmas viz., M. gallisepticum (MG), M. synoviae (MS), M. meleagradis (MM) and M. iowae (MI). The MG and MS are World Organization for Animal Health listed respiratory pathogens. MG causes chronic respiratory disease in chicken and infectious sinusitis in turkey; however, MS causes synovitis and airsacculitis in birds. The infection is transmitted both horizontally and vertically. Prevention and control measures of avian mycoplasmosis mainly comprises of biosecurity, treatment and vaccination. For vaccination of birds, inactivated bacterins, live attenuated and/or recombinant live poxvirus vaccines are commercially available against MG and MS infection. The present systematic review summarizes the different epidemiological studies carried out on MG and MS infection in poultry in different geographical locations of India and abroad over the last decade (2010-2020), economic impact, diagnosis and prevention and control.