Difference between revisions of "Category:Mycoplasmas"

Revision as of 11:45, 14 May 2010

Pathogens belong to the Mycoplasma and Ureaplasma genera
Cause many diseases especially respiratory diseases of farm animals including contagious bovine pleuropneumonia
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

Smallest free-living prokaryotic organism
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

Mycoplasmas adhere to host cells and produce toxins
Some adhere to neutrophils and macrophages and prevent phagocytosis
Mycoplasmas induce proliferation of macrophages and [[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

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

M. hyosynovia and M. hyorhinis produce syndromes similar to Glasser's disease with milder expression, rarely menigitis and arthritis
M. hyorhinis causes a chronic progressive polyserositis in pigs under 10 weeks old
A fever, laboured breathing, lameness and swollen joints occur
Serofibrinous pleurisy, pericarditis and peritonitis occur
Treatment includes tylosin and lincomycin
M. hyorhinis causes a polyarthritis in pigs of 10-30 weeks old, leading to transient lameness

M. bovis, M. dispar and Ureaplasma can be involved in Enzootic pneumonia of calves
M. ovipneumoniae is implicated in enzootic pneumonia of lambs
M. felis may be involved in mild respiratory infection
Mycoplasmas may cause lymphocytic chronic inflammation (peribronchiolar and perialveolar cuffing)
Cause peritonitis in sheep, peritonitis in goats and peritonitis in pigs

The following 14 pages are in this category, out of 14 total.

@@ Line 58: / Line 58: @@
 [[Mycoplasma mycoides subsp. mycoides]]
-===[[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of pigs|Enzootic pneumonia of pigs]]===
+[[Mycoplasma hyopneumoniae]]
-*[[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of pigs|Enzootic pneumonia of pigs]] caused by ''M. hyopneumoniae''
-*Occur in unfavourable conditions with poor ventilation, overcrowding and temperature fluctuations
-*Stunted growth rates, coughing and occasionally respiratory distress
-*Consolidation in apical and cardiac lung lobes
-*Immunofluorescence of lung tissue and complement fixation test or ELISA used for identification
-*Treatment includes in-feed antibiotics such as tylosin, lincomycin and tiamulin
-*Absent in specific-pathogen-free herds
 ===''M. hyorhinis'' and ''M. hyosynoviae'' of pigs===