Disseminated Rhodococcus equi infection in dromedary camels (Camelus dromedarius)

• Published in: Veterinary microbiology Vol. 149; no. 1-2; pp. 269 - 272
• Main Authors: Kinne, J., Madarame, H., Takai, S., Jose, S., Wernery, U.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 21-04-2011; Amsterdam; New York: Elsevier; Elsevier
• Subjects: Actinomycetales Infections - microbiology; Actinomycetales Infections - pathology; Actinomycetales Infections - veterinary; Animals; Bacterial Proteins - genetics; Bacteriology; Biological and medical sciences; Camel; Camelus - microbiology; Camelus dromedarius; Female; Fundamental and applied biological sciences. Psychology; Liver - microbiology; Liver - pathology; Lung - microbiology; Lung - pathology; Lung Abscess - microbiology; Lung Abscess - pathology; Microbiology; Miscellaneous; Mycobacterium; Plasmids - genetics; Pneumonia; Polymerase Chain Reaction - veterinary; Rhodococcus equi; Rhodococcus equi - genetics; Rhodococcus equi - isolation & purification; Rhodococcus equi - pathogenicity; United Arab Emirates; Virulence - genetics; Pneumonia; Rhodococcus equi; Camel; Camelus dromedarius; Lung disease; Farming animal; Ruminant animal; Respiratory disease; Vertebrata; Mammalia; Bacteria; Actinomycetes; Artiodactyla; Disseminated; Veterinary; Ungulata
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2010.09.037

Rhodococcus (R). equi, a recognized pathogen in horses, is emerging as a human opportunistic pathogen, especially in immunocompromized people. It affects also New World camelids, but there are no reports of R. equi infection in Old World camelids yet.
Four cases of disseminated R. equi infection in adult breeding dromedaries occurred at one camel farm near Dubai within 16 months of each other. At necropsy the lungs were diffusely consolidated with large caseous areas. Histology revealed severe suppurative to necrotising pneumonia with multiple encapsulated abscesses. Immunohistochemistry enabled the detection of 15- to 17-kDa antigens (VapA) of R. equi in the lung sections. High numbers of R. equi were isolated from the lung lesions as well as from liver, spleen and mediastinal lymph nodes, indicative of septicaemia. The isolated strains were PCR-positive for the specific virulence plasmid (VapA-Gen) of R. equi, indicating virulent strains and containing an 85-kb type I plasmid.
This is the first report of disseminated R. equi infection in Old World camelids. Since adult camels in general do not suffer from bacterial caused pneumonia (except tuberculosis), this is a new emerging disease for camels.