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Experimental leprosy in monkeys. I. Sooty mangabey monkeys: transmission, susceptibility, clinical and pathological
1Department of Microbiology, Tulane Regional Primate Research Center, Covington, LA, USA.
Abstract:
A total of 31 sooty mangabey monkeys (SMM) (Cercocebus torquatus atys) inoculated by various routes with differing numbers of SMM-origin Mycobacterium leprae (ML) and 4 SMM inoculated with human-origin ML were observed for 4-12 years. SMM-origin ML was more pathogenic in SMM than human-origin ML. The spectrum of disease ranged from indeterminate to borderline and lepromatous in different animals. Some animals developed pure neural leprosy. Erythema nodosum leprosum (SNL) was also observed. Combined intravenous/intracutaneous (IV/IC) routes of inoculation more effectively induced advancing, disseminated lepromatous forms of leprosy; IV or IC routes alone were less effective at comparable doses. Total IV/IC doses of SMM-origin ML equal to or greater than 5 x 10(8), with morphologic indices (MIs) ranging from 5 to 10%, produced advancing, disseminated LL leprosy in 92% of SMM. Lower IV/IC doses and inoculations by a single IV or IC route produced fewer leprosy infections and more spontaneous regressions. As a species, captive SMM are highly susceptible to experimental leprosy and provide an excellent model for the longitudinal study of leprosy.
Insights
Sooty mangabey monkeys (SMM) are highly susceptible to leprosy. Mycobacterium leprae from SMM is more pathogenic than human strains, making SMM an excellent model for leprosy research.
Area of Science:
- Primate immunology
- Infectious diseases
- Mycobacterial infections
Background:
- Leprosy remains a significant global health concern.
- Animal models are crucial for understanding leprosy pathogenesis and developing treatments.
- Sooty mangabey monkeys (Cercocebus torquatus atys) have been utilized in leprosy research.
Purpose of the Study:
- To evaluate the susceptibility of sooty mangabey monkeys (SMM) to experimental leprosy.
- To compare the pathogenicity of SMM-origin Mycobacterium leprae (ML) versus human-origin ML in SMM.
- To determine optimal inoculation routes and doses for inducing leprosy in SMM.
Main Methods:
- 31 SMM were inoculated with SMM-origin ML and 4 with human-origin ML via various routes and doses.
- Animals were observed for 4-12 years to monitor disease development.
- Disease spectrum, including pure neural leprosy and erythema nodosum leprosum (SNL), was assessed.
Main Results:
- SMM-origin ML was more pathogenic in SMM than human-origin ML.
- Combined intravenous/intracutaneous (IV/IC) inoculation routes were most effective for inducing disseminated lepromatous leprosy.
- High IV/IC doses (≥5 x 10^8) with specific morphologic indices (5-10%) resulted in LL leprosy in 92% of SMM.
- Lower doses or single routes led to fewer infections and more spontaneous regressions.
Conclusions:
- Captive SMM are highly susceptible to experimental leprosy.
- SMM provide an excellent model for longitudinal leprosy studies.
- SMM-origin ML is more virulent in this primate model, offering insights into host-pathogen interactions.