Leprosy survey among rural communities and wild armadillos from Amazonas state, Northern Brazil

Abstract

There is evidence that in southern US, leprosy is a zoonosis infecting wild Dasypus novemcinctus armadillos but the extent of this finding is unknown. This ecological study investigated leprosy in rural communities and in wild armadillos from the Brazilian Amazon. The study area was the Mamiá Lake of Coari municipality, Amazonas State, Northern region, a hyper endemic leprosy area where residents live on subsistence farming, fishing and armadillo hunting and its meat intake are frequent. The leprosy survey was conducted in sixteen communities by a visiting team of specialists. Local partakers provided wild armadillos to investigate M. leprae infection. Volunteers had complete dermato-neurological examination by a dermatologist with expertise in leprosy diagnosis, suspect skin lesions were biopsied for histopathology (Hematoxylin-eosin/HE, Fite-Faraco/FF staining); slit skin smears were collected. Armadillos’ tissue fragments (skins, spleens, livers, lymph nodes, adrenal glands, others) were prepared for histopathology (HE/FF) and for M. leprae repetitive element-RLEP-qPCR. Among 176 volunteers, six new indeterminate leprosy cases were identified (incidence = 3.4%). Suspect skin sections and slit skin smears were negative for bacilli. Twelve wild D. novemcinctus were investigated (48 specimens/96 slides) and histopathological features of M. leprae infection were not found, except for one skin presenting unspecific inflammatory infiltrate suggestive of indeterminate leprosy. Possible traumatic neuroma, granuloma with epithelioid and Langhans cells, foreign-body granuloma were also identified. Granulomatous/non-granulomatous dermatitides were periodic-acid-Schiff/PAS negative for fungus. M. leprae-RLEP-qPCR was negative in all armadillos’ tissues; no bacillus was found in histopathology. Our survey in rural communities confirmed the high endemicity for leprosy while one armadillo was compatible with paucibacillary M. leprae infection. At least in the highly endemic rural area of Coari, in the Brazilian Amazon region where infectious sources from untreated multibacillary leprosy are abundant, M. leprae infected armadillos may not represent a major source of infection nor a significant public health concern.

Prevalence of Mycobacterium leprae in armadillos in Brazil: A systematic review and meta-analysis

“…A later study confirmed these findings in Espírito Santo [7], and M. leprae was subsequently reported in wild armadillos from the northern states of Ceará [8] and Pará [3]. Conversely, studies in São Paulo and Mato Grosso do Sul [9] and Amazonas [10] found no M. leprae in wild armadillos.…”

“…The four remaining studies were located in the north or north east of Brazil: a 2012 study caught 29 armadillos (27 Dasypus novemcinctus, 2 Euphractus sexcinctus) between July and August 2007 in the north east region state of Ceará [8]; two more recent studies caught 16 and 12 Dasypus novemcinctus from the states of Pará (unspecified dates) and Amazonas (expedition in August 2015) [10], respectively; the most recent study (2019) caught 20 Euphractus [22]. The 10 included studies yielded a total sample of 302 armadillos (295 live, 7 roadkill), comprising 207 (69%) Dasypus novemcinctus ('Nine-banded'), 67 (22%) Euphractus sexcinctus ('Six-banded'), 16 (5%) Priodontes maximus ('Giant'), 10 (3%) Cabassous unicinctus ('Southern Naked-tailed'), and 2 (1%) Cabassous tatouay ('Greater Naked-tailed') ( Fig 2).…”

“…The 10 included studies yielded a total sample of 302 armadillos (295 live, 7 roadkill), comprising 207 (69%) Dasypus novemcinctus ('Nine-banded'), 67 (22%) Euphractus sexcinctus ('Six-banded'), 16 (5%) Priodontes maximus ('Giant'), 10 (3%) Cabassous unicinctus ('Southern Naked-tailed'), and 2 (1%) Cabassous tatouay ('Greater Naked-tailed') ( Fig 2). Armadillos were captured by local hunters in 7 studies [3,8,10,22,23,26,27], by veterinarians or wildlife specialists in 2 studies [7,28] and the method was not reported in one study [9].…”

“…Armadillos were anaesthetized and euthanised in 5 studies [7][8][9][10]22], captured and released in 4 studies [23,[26][27][28] or specimens were obtained from animals recently killed by local hunters [3]. Blood specimens were taken in 7 studies [7,9,22,23,[26][27][28] but only three authors (Deps [23,26,27], Pedrini et al [9], da Silva Ferreira et al [22]) used these to test for M. leprae.…”

“…Blood specimens were taken in 7 studies [7,9,22,23,[26][27][28] but only three authors (Deps [23,26,27], Pedrini et al [9], da Silva Ferreira et al [22]) used these to test for M. leprae. A wide range of tissue types were sampled (S1 Data), with all except 2 studies (Pedrini et al PLOS NEGLECTED TROPICAL DISEASES [9], da Silva Ferreira et al [22]) using spleen specimens and all except 2 (Stefani et al [10], da Silva et al [3]) using liver and/or ear tissue specimens. One study (Pedrini et al [9]) also tested for M. leprae in one faeces specimen and a small number (5) of nostril swabs.…”