Hansen Disease (Leprosy) and Armadillo Exposure in Arkansas: A Case Series

Abstract

Background: Although most cases of Hansen disease (HD) in the United States are imported from endemic areas, a subset of cases are relate to exposure to nine-banded armadillos. Several recent cases of HD in Arkansas occurred in patients who had not traveled to endemic areas and who reported variable degrees of armadillo exposure. Objective: The purpose of this study was to report 6 cases of HD diagnosed in Arkansas between 2004 and 2016. The secondary purpose was to explore the correlation between exposure to the nine-banded armadillo as it pertains to transmission of the disease. Methods: The referring clinician of each patient was contacted to gather information regarding the patient's clinical presentation, armadillo exposure, and travel history. In addition, the Arkansas Department of Health was consulted to review the demographics of individuals diagnosed with HD in the past 15 years and to review the distribution of HD throughout the state of Arkansas. Results: Six domestic cases of HD were associated with both direct and indirect exposure to armadillos. Limitations: Armadillo exposure may be underreported in patients with HD because of fear of stigmatization and/or lack of access to care. Conclusions: Direct exposure to armadillos does not appear to be required for transmission of HD making a soil-mediated mechanism of indirect exposure plausible.

Mycobacterial skin infection

“…The current stagnation in leprosy incidence has been attributed both to the large number of undetected cases, who contribute to furthering human to human transmission, and to the role of animal and environmental reservoirs [ 28 ▪▪ , 31 ▪▪ , 32 ]. Armadillo species and red squirrels were found to be wildlife reservoirs of M. leprae [ 31 ▪▪ , 33 ]. Viable M. leprae has also been detected from environmental sources (water and soil) in Indonesia, India, Brazil and Bangladesh [ 34 ].…”

“…Recent studies have shown a potential role of vectors like kissing bugs and free-living amoebas [28 && ]. The clinical presentation is determined by the microorganism's tropism for skin and peripheral nerves (preferentially Schwann cells) and its variability by the genetic background and the immune response of the host [27,33,35 ]. Murine models have shown that the Th1 cascade, with IL-2 and IFN-gamma production, may be responsible for tuberculoid lesions (Fig.…”

Leprosy: what is new

“…Armadillos are highly prevalent in Central and South America and likely entered the United States from Mexico. 11,12 These geographic hot spots of leprosy may have continued transmission because of their respective armadillo population.…”

“…Human‐to‐human transmission is not the only way leprosy can be acquired; armadillos are considered a natural host and reservoir. Armadillos are highly prevalent in Central and South America and likely entered the United States from Mexico 11,12 . These geographic hot spots of leprosy may have continued transmission because of their respective armadillo population.…”

Leprosy: clinical and immunopathological characteristics

“…1 Armadillos of the Dasypus novemcinctus species can also be naturally infected by M. leprae , and there is evidence that armadillos can transmit the disease to humans. 2 Another bacterium, Mycobacterium lepromatosis , discovered in Mexico in 2008, has also been implicated as the etiological agent of leprosy, initially associated with multibacillary forms but later also found in paucibacillary forms. 3 …”