Canis ISSN: 2398-2942

Mycoplasmosis

Contributor(s): Karen Coyne, Severine Tasker

Introduction

  • Cause:
    • Infection with Mycoplasma spp.
    • Mycoplasma species are characterized as gram negative, non-acid fast prokaryotes, that lack a cell wall.
    • Mycoplasmas are currently divided into hemotropic and non-hemotropic types.
    • Some Mycoplasmas are Ureaplasmas; these usually have an affinity for the genitourinary tract.
  • Signs: respiratory disease, urogenital disease, anemia, colitis.
  • Diagnosis: bacterial culture for those species which are culturable; molecular tests, PCR.
  • Treatment: non beta-lactam antibiotic therapy.
  • Prognosis: usually good.
  • Mycoplasmas can be difficult to identify; therefore the majority of studies have investigated the presence or absence of Mycoplasma spp in a variety of clinical samples but the role of Mycoplasma spp in the pathogenesis of disease remains to be elucidated.
  • Some species cause hemolysis on blood agar, suggesting that hemolytic enzymes may be produced.
  • Each Mycoplasma species has a distinct antigen that doesn't bind antisera to other species.
  • Mycoplasmas depend on nourishment from a rich environment, which they find on mucosal membranes of the respiratory and urogenital tracts of dogs. Other species are hemotropic, living on the surface of red blood cells.
  • Several species of Mycoplasma have been isolated from the upper respiratory tract of healthy and diseased dogs including:
  • Mycoplasmas are rarely isolated from the lower respiratory tract of healthy animals, but in diseased animals, ie those presenting with pneumonia, the following species have been isolated:
    • M. canis.
    • M. spumans.
    • M. edwardii.
    • M. cynos.
    • M. feliminutum.
    • M. gateae.
    • M. bovigenitalium.
    • Ureaplasmaspp.
  • In the genital and urinary tract of healthy animals the following species have been isolated:
    • M. canis.
    • M. cynos.
    • M. felis.
    • Ureaplasma spp.
    • M. spumans.
  • Hemotropic mycoplasmas (hemoplasmas) can be detected in the blood of dogs. However disease is rare in immunocompetant dogs and clinical signs of anemia are usually confined to dogs that are immunocompromised or splenectomized Splenectomy.

Pathogenesis

Etiology

  • Mycoplasma spp, M. canisM cynosM haemocanis and Candidatus M. haematoparvum are primarily associated with mycoplasmosis in dogs.

Predisposing factors

General

  • Opportunistic infections.
  • Concurrent disease/mixed bacterial infections.
  • Immunosuppression.
  • Splenectomy Splenectomy for the hemoplasmas.

Pathophysiology

Non-hemotropic Mycoplasmosis

Respiratory disease

  • Mycoplasma spp are thought to form part of the normal flora in the upper respiratory tract of dogs.
  • Up to 25% of healthy dogs will harbor Mycoplasma.
  • Mycoplasma cynos is the only species to be commonly associated with respiratory disease in dogs.
  • During pneumonia the lungs become colonized with mycoplasma.
  • Mycoplasmas have been isolated from a higher proportion of young dogs (usually <1 year old) presenting with pulmonary disease.
  • Dogs with concurrent infection with Bordetella bronchiseptica Bordetella bronchiseptica or Streptococci Streptococcus spp in the lower respiratory tract are more likely to be infected with Mycoplasma, and the presence of the bacteria is likely to be associated with septic infection.
  • It is unclear as to whether Mycoplasma is a primary or secondary pathogen in canine pulmonary disease.
  • In dogs with impaired pulmonary clearance, due to viral infection, mycoplasmas that are inhaled from the upper respiratory tract may establish a secondary infection in the lung and/or pleural cavity.
  • Several species of Mycoplasma have been isolated from the respiratory tract of healthy and diseased dogs (see above).
  • Mycoplasma may transcend the respiratory tract from the oropharynx following infection or immunosuppression.
  • Pneumonia Lung: bacterial pneumonia , destruction and loss of cilia and alveolar infiltration with macrophages and neutrophils have been reproduced during experimental infection with M. cynos.
  • Younger dogs (< 1 year old) appear to me more likely to have M. cynos infections than older dogs.
  • The role played by other mycoplasma species in canine respiratory disease remains to be established.

Urogenital disease

  • Mycoplasmas are isolated in large numbers from the urine of dogs with urinary tract infections.
  • Between 30%-50% male dogs and 23-75% female dogs have been reported as having mycoplasmas in the genital tract.
  • To establish the role of mycoplasma in pathogenesis of urogenital disease, urine should be collected by cystocentesis Cystocentesis and no other bacteria should be isolated.
  • Collection of voided urine, or via catheterization, may contaminate the urine with other bacterial species.
  • Mixed infections with other bacteria and Mycoplasma species are common.
  • M. canis has been isolated from dogs with urogenital disease and infertility.
  • M. canis has been cultured from the prostate, epididymis and the chronically inflamed bladder wall in dogs with urogenital disease that have been on prolonged antibiotic therapy Therapeutics: urinary system.
  • Conditions that that pre-dispose an animal to bacterial infection, such as tumors and urinary calculi, may promote Mycoplasma growth.
  • Mycoplasmas of the reproductive tract are considered to be opportunistic.
  • Experimental infection with M. canis produced chronic urethritis, and epididymitis Orchitis / epididymitis in 50% males tested and in females enlarged uterus and endometritis was seen.
  • Several species of Mycoplasma have been isolated from the vagina/prepuce, suggesting an association of these bacteria (ureaplasmas) with infertility in male dogs, however conclusive evidence is lacking.

Colitis

  • Up to 30% of dogs harbor mycoplasmas in the colon, here they are considered part of the normal flora.
  • Mycoplasmas are occasionally isolated from colonic and rectal biopsies of dogs with colitis Colitis: parasitic / infectious , however, colitis has been failed to be reproduced during experimental infection with Mycoplasma spp.

Hemotropic Mycoplasmosis (Hemoplasmosis)

Canine anemia

  • Mycoplasma haemocanis, formally known as a Haemobartonella species, has recently been reclassified within the genus Mycoplasma by analysis of the 16S rRNA gene.
  • M. haemocanis is the main causative agent of hemotropic mycoplasmosis in dogs.
  • More recently infection with an additional hemoplasma, Candidatus M. haematoparvum, has been reported.
  • Infection with M. haemocanis has been documented in dogs all over the world.
  • The acute form of M. haemocanis disease is characterized by a rapidly developing anemia, usually in immunocompromised or splenectomized dogs.
  • Unless other diseases are present, clinical signs are rarely observed in non-splenectomized dogs infected with M. haemocanis.
  • Concurrent symptoms including lethargy, weight loss, fever and anorexia are found in some clinical cases.
  • In more severe cases acute hemolytic anemia Anemia: immune mediated hemolytic occurs. Dogs may show autoagglutination and can be Coombs positive. In rare cases fatalities may ensue.
  • Candidatus M. haematoparvum has been associated with anemia in an immunocompromised dog.
  • Transmission is by the brown dog tick Rhipicephalus sanguineus Rhipicephalus sanguineus.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Barker E N, Tasker S, Day M J, Warman S M, Woolley K, Birtles R, Georges K C, Ezeokoli C D, Newaj-Fyzul A, Campbell M D, Sparagano O A, Cleaveland S & Helps C R (2010) Development and use of real-time PCR to detect and quantify Mycoplasma haemocanis and "Candidatus Mycoplasma haematoparvum" in dogs. Vet Microbiol 140 (1-2) 167-170 PubMed.
  • Hulme-Moir K L, Barker E N, Stonelake A, Helps C R & Tasker S (2010) Use of real-time quantitative polymerase chain reaction to monitor antibiotic therapy in a dog with naturally acquired Mycoplasma haemocanis infection. J Vet Diag Invest 22 (4), 582-587 PubMed.
  • Roura X, Peters I R, Altet L, Tabar M D, Barker E N, Planellas M, Helps C R, Francino O, Shaw S E, Tasker S (2010) Prevalence of hemotropic mycoplasmas in healthy and unhealthy cats and dogs in Spain. J Vet Diagn Invest 22 (2), 270-274 PubMed.
  • Mannering S A, McAuliffe L, Lawes J R, Erles K, Brownlie J (2009) Strain typing of Mycoplasma cynos isolates from dogs with respiratory disease. Vet Microbiol 135 (3-4), 292-296 PubMed.
  • Rycroft A N, Tsounakou E, Chalker V (2007) Serological evidence of Mycoplasma cynos infection in canine infectious respiratory disease. Vet Microbiol 120 (3-4), 358-362 PubMed.
  • Chalker V J (2005) Canine mycoplasmas. Res Vet Sci 79 (1), 1-8 PubMed.
  • Chalker V J, Owen W M, Paterson C, Barker E, Brooks H, Rycroft A N, Brownlie J (2004) Mycoplasmas associated with canine infectious respiratory disease. Microbiology 150 (Pt 10), 3491-3497 PubMed.

Other sources of information

  • Tasker S (2008)Canine and Feline Hemotropic Mycoplasmosis.In:Kirks Current Veterinary Therapy XIV. Edited by J D Bonagura and D Twedt. Elsevier Inc., St. Louis, USA. Chapter 271 pp 1245-1248.
  • Greene C E (2006)Mycoplasmal, Ureaplasmal and L form infections.In:Infectious diseases of the Dog and Cat. 2nd Edn. Ed. Greene C E. W B Saunders Co. pp 260-265.


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