terium leprae . 5 Factors resulting in susceptibility to infection and development of clinical leprosy remain unknown . The respiratory route has historically been the main mode of transmission . 6 Although leprosy is curable , delayed diagnosis may lead to irreversible neurologic sequelae or complications from immune reactions . 6 Immune reactions are inflammatory complications consisting of extension or worsening of skin lesions or symptoms secondary to immunologic responses to Mycobacterium leprae . There are two types of immune reactions of leprosy : type 1 lepra reaction ( reversal reaction ) characterized by enhancement of cell-mediated immunity within existing skin lesions and type 2 lepra reaction ( erythema nodosum leprosum ) associated with immune-complex formation . 6 , 7
While currently considered a rare disorder , the WHO reported 208,619 worldwide and 185 new cases in the US in 2018 . 8 Nine-banded armadillos , the only animal reservoir known to transmit leprosy to humans , have recently emerged as a source of zoonotic leprosy in the southern US . Armadillos are highly susceptible to infection with Mycobacterium leprae and may have massive burdens of bacilli in their tissues . While infection in armadillos was first detected in 1975 , it is thought to have originated when leprosy was brought to the Americas by European immigrants over 500 years ago . Within the last decade , two strains of Mycobacterium leprae ( genotypes 31-2-V1 and 31-2-V15 ) circulating in armadillos were found to be identical to strains isolated from humans with leprosy in southern US who had never resided in other countries or been in contact with other people with leprosy . 9 Of new cases referred to the National Hansen ’ s Disease Program ( NHDP ) from 2007 through 2012 , over 40 % were due to one of two armadillo-related strains . 9 , 10
According to most recent data provided by the NHDP , 96 of 178 new cases reported in 2015 occurred in one of seven states in the southern US where Mycobacterium leprae has been isolated from nine-banded armadillos . Approximately two-thirds of these cases occurred in US-born citizens who had never resided outside of the country , implying local acquisition . Leprosy is infrequently identified in WV . Only one new case of leprosy was reported in WV from 2005 through 2015 . 11 We believe our patient acquired leprosy from exposure to nine-banded armadillos while visiting her son in Texas .
FIGURE 1
( A ) Before initiation of treatment ( B ) After 2 months of dapsone and rifampin ( C ) After 5 months of dapsone and rifampin
FIGURE 2 c
( A ) H & E Stain : Well-formed , epithelioid granulomas ( arrows ) ( B ) Fite Stain : Scarce AFB ( arrowheads )
Mycobacterium leprae is a slow growing acid-fast bacillus that is not culturable on laboratory media . 6 Due to low viability of human biopsy derived inoculum , cool temperature required for survival and multiplication , and a long generation time , cultivation for the purpose of research requires inoculation of armadillos or footpads of immunodeficient mice . 12 Immunohistopathologic spectrum of leprosy ranges from tuberculoid to lepromatous subtypes . Tuberculoid leprosy is characterized by a strong cell-mediated immune response . It manifests most often as hypoesthesia of a few , well-defined macules or plaques with asymmetric or single peripheral nerve enlargement . While few cases of type 1 lepra reaction have been reported , the risk of immune reaction occurring in association with tuberculoid leprosy is exceptionally low . Histopathology reveals well-organized epithelioid granulomas on H & E stain and scarce or absent AFB on
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