Changes

*Pathogens belong to the ''Mycoplasma'' and ''Ureaplasma'' genera

Pathogens belong to the ''Mycoplasma'' and ''Ureaplasma'' genera. They cause many diseases, especially respiratory diseases of farm animals including [[Contagious Bovine Pleuropneumonia]]. They can be involved in [[Mastitis]] and conjunctivitis in cattle and are implicated in respiratory and urinary tract diseases in dogs and cats.

*Cause many diseases especially respiratory diseases of farm animals including contagious bovine pleuropneumonia

There are non-pathogenic mycoplasmas present in the rumen that live on the mucous membranes of the oronasal cavity, conjunctiva and intestines. Stress factors and concurrent disease may predispose to tissue invasion. ''Mycoplasmas'' are usually host-specific and have limited survival in the environment.

*Can be involved in mastitis and conjunctivitis in cattle

*Implicated in respiratory and urinary tract diseases in dogs and cats

*Non-pathogenic mycoplasmas present in the rumen

*Live on mucous membranes of oronasal cavity, conjunctiva and intestines

*Stress factors and concurrent disease may predispose to tissue invasion

*Usually host-specific

*Limited survival in the environment

===Characteristics===

==Characteristics==

*Smallest free-living prokaryotic organism

The ''Mycoplasmas'' are the smallest, free-living prokaryotic organisms. They are pleomorphic organisms and have no peptidoglycan cell wall. They are susceptible to dessication, heat and disinfectants and require enriched media containing animal protein, sterol and a source of DNA for growth. Their colonies have a fried egg appearance. Most are facultative anaerobes.

*Pleomorphic organisms

*Have no peptidoglycan cell wall

*Susceptible to dessication, heat and disinfectants

*Require enriched media containing animal protein, sterol and a source of DNA for growth

*Colonies have a fried egg appearance

*Most are facultative anaerobes

===Pathogenesis and pathogenicity===

==Pathogenesis and pathogenicity==

*Mycoplasmas adhere to host cells and produce toxins  

''Mycoplasmas'' adhere to host cells and produce toxins. Some adhere to [[Neutrophils|neutrophils]] and macrophages and prevent phagocytosis. ''Mycoplasmas'' induce proliferation of macrophages and [[[[Monocytes|monocytes]]]], and the release of cytokines such as TNF and interleukins. They cause damage to cilia in the respiratory tract leading to pneumonia. Molecular mimicry allows some ''mycoplasmas'' to avoid the host immune response and may initiate immune-mediated disease.

*Some adhere to [[Neutrophils|neutrophils]] and macrophages and prevent phagocytosis

*Mycoplasmas induce proliferation of macrophages and [[[[Monocytes|monocytes]]]], and release of cytokines such as TNF and interleukins

*Cause damage to cilia in the respiratory tract leading to pneumonia

*Molecular mimicry allows some mycoplasmas to avoid the host immune response and may initiate immune-mediated disease

===Diagnosis===

==Diagnosis==

*Samples can be tested for the presence of mycoplasmas by fluorescent antibody techniques, peroxidase techniques and PCR

Samples can be tested for the presence of mycoplasmas by fluorescent antibody techniques, peroxidase techniques and PCR. Biochemical profiles such as urease production can be used for identification. ''Ureaplasmas'' produce urease, whereas ''Mycoplasmas'' do not metabolise urea. Serolgy is required for specific identification including complement fixation tests, ELISA, agglutination tests and haemagglutination-inhibition tests. Growth inhibition tests using specific antisera can be used as well as fluorescent antibody tests.

*Biochemical profiles such as urease production can be used for identification

*''Ureaplasmas'' produce urease, whereas ''Mycoplasmas'' do not metabolise urea

*Serolgy is required for specific identification including complement fixation tests, ELISA, agglutination tests and haemagglutination-inhibition tests

*Growth inhibition tests using specific antisera can be used as well as fluorescent antibody tests

===Other mycoplasmas===

==Other mycoplasmas==

*''M. bovis'', ''M. dispar'' and ''Ureaplasma'' can be involved in [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

*''M. bovis'', ''M. dispar'' and ''Ureaplasma'' can be involved in [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]