Goat and sheep
M. mycoides subsp. capri is the cause of caprine pleuropneumonia, a serious malady of goats. The disease is prevalent in certain parts of this country. The mortality rate is very high, but mild cases also develop and become a source of infection for other animals. The disease spreads by air-borne infection. The incubation period is about 4 days to 4 weeks. The affected animals become dull and there is rise in temperature, laboured breathing, continuous nasal discharge, coughing, diarrhoea and rapid loss of condition. The mortality rate is up to 90 %. The lung lesions are similar to those seen in bovine pleuropneumonia, showing hepatization and thickened interlobular septa. Pleurisy with effusions is a constant lesion. The bronchial and mediastinal lymph nodes also show congestion and oedema.
The diagnosis is based on the nature of the disease and post-mortem lesions. The isolation of causal organism from affected tissues is difficult. In acute cases, the organisms can be seen under dark-ground illumination in pleural exudates. Contagious pleuropneumonia can be controlled by slaughter of infected and contact goats and through disinfection of infected premises. A satisfactory vaccine has not been developed as yet but a live avirulent strain of organism is used for producing active immunity.
An organism similar to M . capri causes arthritis in goats. A large number of Mycoplasma species have been isolated from goats causing oedematous lesions, polyarthritis and mastitis. Some species are non-pathogenic. M. agalactiae causes contagious agalactia in sheep and goats. The infection spreads by ingestion and via teat canal causing infection of joints, eyes and udder of lactating animals. The animals of any age suffer from this disease. The incubation period is 5-7 days. There is rise in temperature, listlessness and in appetence. The affected animal may die at this stage, or the disease may develop in localized areas including joints of lower limbs, eyes and udders of lactating animals. The milk yield decreases and is replaced by small quantities of purulent secretions and development of fibrosis in udder. The diagnosis is based on isolating the organisms from udder secretions, joint fluid or blood. Contagious agalactia is controlled by slaughter and disinfection. Vaccination has been attempted to produce active immunity.
Pigs
Mycoplasma infection causes arthritis in limb joints in pigs.. Infection with M. hyopneumoniae gives rise to symptoms of coughing and chronic pneumonia.
Poultry
M. gallisepticum causes chronic respiratory disease (CRD) in chicks. The predisposing factors are concurrent bacterial and viral infections. The disease is characterized by nasal discharge, shaking of head, coughing, tracheal rales and swelling of infraorbital sinuses. The affected birds suffer from loss of condition, reduced egg production and lowered fertility. The infection passes to next generation through egg. Hence it is absolutely essential to use Mycoplasma free embryos for production of vaccines. Ideally it is preferable to use Specific pathogen free (SPF) embryos.
The diagnosis of the disease is done by observing symptoms and lesions and employing serological tests like rapid serum plate agglutination test, tube agglutination test and haemagglutination inhibition test. The diseased birds should be destroyed. Egg transmission can be prevented by dipping the eggs in antibiotic solutions like tylosin and erythromycin, before hatching.M. synoviae is the cause of infectious synovitis in chicken and turkey poults. M.meleagridis is responsible for air sacculitis in turkeys. Since turkey farming is coming up in India , it is necessary to look for these organisms