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Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining
Published on: December 23, 2016
Systemic spironucleosis in 2 immunodeficient rhesus macaques (Macaca mulatta)
1Harvard Medical School, Department of Pathology, New England Primate Research Center, One Pine Hill Drive, Southborough, MA 01772, USA.
Abstract:
Spironucleus spp are parasites of fish and terrestrial vertebrates, including mice and turkeys, that rarely cause extraintestinal disease. Two rhesus macaques (Macaca mulatta) were experimentally inoculated with simian immunodeficiency virus mac251. Both progressed to simian acquired immune deficiency syndrome within 1 year of inoculation and developed systemic protozoal infections in addition to common opportunistic infections, including rhesus cytomegalovirus, rhesus lymphocryptovirus, and rhesus adenovirus. In the first case, the protozoa were associated with colitis, multifocal abdominal abscessation, and lymphadenitis. In the second case, they were one of a number of organisms associated with extensive pyogranulomatous pneumonia and colitis. Ultrastructural, molecular, and phylogenetic analysis revealed the causative organism to be a species of Spironucleus closely related to Spironucleus meleagridis of turkeys. This report is the first of extraintestinal infection with Spironucleus sp in higher mammals and expands the list of opportunistic infections found in immunocompromised rhesus macaques.
Insights
Spironucleus parasites, typically causing mild infections, led to severe systemic disease in two macaques with simian acquired immune deficiency syndrome. This marks the first reported extraintestinal Spironucleus infection in higher mammals.
Area of Science:
- Veterinary Parasitology
- Primate Immunology
- Infectious Diseases
Background:
- Spironucleus species are known fish and terrestrial vertebrate parasites, rarely causing extraintestinal disease.
- Rhesus macaques (Macaca mulatta) are valuable models for studying simian immunodeficiency virus (SIV) infection and acquired immune deficiency syndrome (AIDS).
- Opportunistic infections are common in SIV-infected macaques progressing to AIDS.
Observation:
- Two SIV-inoculated rhesus macaques developed simian AIDS within one year.
- Both macaques presented with systemic protozoal infections alongside common opportunistic viral infections.
- Protozoa were associated with severe gastrointestinal and lymph node pathology in one macaque, and extensive pneumonia in the other.
Findings:
- Ultrastructural, molecular, and phylogenetic analyses identified the protozoan as a Spironucleus species.
- The identified Spironucleus species is closely related to Spironucleus meleagridis, a turkey parasite.
- This is the first documented case of extraintestinal Spironucleus infection in higher mammals.
Implications:
- This study expands the spectrum of opportunistic infections recognized in immunocompromised rhesus macaques.
- It highlights the potential for Spironucleus to cause severe systemic disease in immunocompromised hosts.
- Findings suggest a need for increased awareness of Spironucleus as a potential pathogen in veterinary and comparative medicine contexts.
