Molecular detection of Mycobacterium leprae by Polymerase Chain Reaction in captive and free-ranging wild animals.

Dear Editor:

Leprosy, a disease neglected in many countries, is endemic in Brazil. With a wide diversity of fauna distributed in three biomes (Amazon Forest, Cerrado and Pantanal), the state of Mato Grosso (MT) in the Central-West Region has the highest prevalence of human cases: 7.75 per 10,000 inhabitants. Despite the scarcity of data in the literature on wild animals naturally infected with Mycobacterium leprae, the possibility of transmission to humans cannot be ruled out. Armadillos, red squirrels, and non-human primates are important natural reservoirs of M. leprae reported in the literature, becoming possible sources of bacillary dissemination making it difficult to interrupt the leprosy transmission chain. As data on natural infections are scarce, it is difficult to understand the role of wild animals in transmission of the disease. Therefore, we used PCR to detect the genetic material of M. leprae in nasal swabs of wild animals.

Nasal swabs were collected from 69 captive and free wild animals from the MT and Pantanal regions of Brazil, independent of clinical signs, and sent to the Laboratory of Microbiology and Molecular Biology, according to “Sistema de Autorização e Informação em Biodiversidade” (SISBIO), an authorization and information system for biodiversity (nos. 40617-1 and 42303). The samples were submitted for extraction of genetic material according to the phenol/chloroform method. PCR was performed according to Woods and Cole. The PCR product was purified using a GFX™ PCR DNA and Gel Band Purification kit (GE Healthcare, Piscataway, NJ, USA) and sequenced using an ABI-PRISM 3500 Genetic Analyzer (Life Technologies Corporation, USA). The sequences were deposited in GenBank and compared using the BLAST program (http://www.ncbi.nlm.nih.gov/blast/Blast.cgi). Of the 69 samples (Table 1), six (8.69%) wild-type free and captive animals tested positive for M. leprae by PCR, including one margay (Leopardus wiedii), two lowland tapirs (Tapirus terrestris), two capuchin monkeys (Sapajus apella), and one owl monkey (Aotus trivirgatus). The detection in four different species of wild animals shows the ability of this bacillus to be carried in different hosts. In addition, two animals were from the zoo, that could have acquired M. leprae due to close contact to humans or environmental contamination. However, in literature the mechanism of transmission is not yet fully understood.

Table 1

Epidemiological data and M. leprae PCR test of the animals identified in Mato Grosso – Brazil.

ID	Free-ranging	City	Species	Scientific name	PCR
m962/16	Yes	Jangada	Jaguarundi	Puma yagouaroundi	Negative
m1016/16	Yes	Marcelândia	Jaguar	Panthera onca	Negative
m1102/16	No	Zooa	Cougar	Puma concolor	Negative
m1122/16	No	Zoo	Coati	Nasua nasua	Negative
m1162/16	Yes	Cuiabá	Guinea pig	Cavia porcellus	Negative
m1226/16	Yes	Barra do Bugres	Ocelot	Leopardus pardalis	Negative
m1285/16	Yes	NAb	Jaguarundi	Puma yagouaroundi	Negative
m1294/16	Yes	Várzea Grande	Capybara	Hydrochoerus hydrochaeris	Negative
m1335/16	No	Zoo	Giant anteater	Myrmecophaga tridactyla	Negative
m1336/16	Yes	Rosário Oeste	Giant anteater	Myrmecophaga tridactyla	Negative
m1364/16	Yes	Cuiabá	Collared anteaters	Myrmecophaga tetradactyla	Negative
m1485/16	Yes	Santo Antônio do Leverger	Otter	Lontra longicaudis	Negative
m1491/16	Yes	NA	White-eared opossum	Didelphis albiventris	Negative
m1529/16	No	Zoo	Agouti	Dasyprocta Aguti	Negative
m1787/17	Yes	NA	Owl monkey	Aoutus trivirgatus	Positive Genbank MF975704
m1790/16	Yes	Tangará da Serra	Giant anteater	Myrmecophaga tridactyla	Negative
m1795/16	No	Zoo	Coati	Nasua nasua	Negative
m1796/16	No	Zoo	Agouti	Dasyprocta aguti	Negative
m1862/16	Yes	Várzea Grande	Collared anteaters	Myrmecophaga tetradactyla	Negative
m11/17	Yes	Cuiabá	Capuchin monkey	Sapajus apella	Positive Genbank MF975703
m74/17	No	Zoo	Cougar	Puma concolor	Negative
m153/17	Yes	Cuiabá	White-eared opossum	Didelphis albiventris	Negative
m234/17	No	Zoo	Cougar	Puma concolor	Negative
m235/17	Yes	Cuiabá	Sagui	Callithrix sp.	Negative
m248/17	No	Zoo	Maned wolf	Chrysocyon brachyurus	Negative
m261/17	Yes	NA	Black owler monkey	Alouatta caraya	Negative
m305/17	No	Zoo	Lowland tapirs	Tapirus terrestris	Positive Genbank MF975707
m345/17	No	Zoo	Cougar	Puma concolor	Negative
m379/17	Yes	NA	Black-tufted marmoset	Callithrix penicillata	Negative
m514/17	No	Zoo	White-cheeked spider monkey	Ateles marginatus	Negative
m520/17	No	Zoo	White-cheeked spider monkey	Ateles marginatus	Negative
m530/17	Yes	NA	Capuchin monkey	Sapajus apella	Positive Genbank MF818035
m539/17	Yes	NA	Monkey	NA	Negative
m542/17	Yes	Santo Antônio do Leverger	Owl monkey	Aotus sp.	Negative
m543/17	Yes	Santo Antônio do Leverger	Owl monkey	Aotus sp.	Negative
m705/17	Yes	Cuiabá	Monkey	NA	Negative
m709/17	Yes	Poconé	Giant anteater	Myrmecophaga tridactyla	Negative
m743/17	No	Zoo	Coati	Nasua nasua	Negative
m748/17	Yes	Poconé	Crab-eating fox	Cerdocyon thous	Negative
m765/17	No	Zoo	Ocelot	Leopardus pardalis	Negative
m787/17	No	Zoo	Margay	Leopardus weidii	Positive Genbank MF975706
m809/17	Yes	Rondonópolis	Lowland tapirs	Tapirus terrestris	Positive Genbank MF975705
m874/17	No	Zoo	Coati	Nasua nasua	Negative
m878/17	Yes	Campo Verde	Howler monkey	Alouatta sp.	Negative
m879/17	No	Zoo	Crab-eating fox	Cerdocyon thous	Negative
m742/17	No	Zoo	Coati	Nasua nasua	Negative
m721/17	No	Zoo	Coati	Nasua nasua	Negative
m871/17	Yes	Cuiabá	Owl monkey	Aoutus azare	Negative
m897/17	No	Zoo	Crab-eating fox	Cerdocyon thous	Negative
m881/17	No	Zoo	Crab-eating fox	Cerdocyon thous	Negative
m1055/17	Yes	NA	Capuchin monkey	Sapajus apella	Negative
m1070/17	Yes	NA	Capybara	Hydrochoerus hydrochaeris	Negative
m1126/17	Yes	Tangará da Serra	Cougar	Puma concolor	Negative
m1153/17	No	Zoo	Crab-eating fox	Cerdocyon thous	Negative
m1247/17	Yes	NA	Capuchin monkey	Sapajus apella	Negative
m1248/17	Yes	NA	Capuchin monkey	Sapajus apella	Negative
m1249/17	Yes	NA	Capuchin monkey	Sapajus apella	Negative
m1267/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1268/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1269/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1270/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1271/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1272/17	Yes	Poconé	Capybara	Hydrochoerus hydrochaeris	Negative
m1290/17	Yes	Cuiabá	Owl monkey	Aoutus nigriceps	Negative
m1309/17	Yes	Cáceres	Cougar	Puma concolor	Negative
m1313/17	Yes	Cuiabá	Capuchin monkey	Sapajus apella	Negative
m1327/17	Yes	NA	Black owler monkey	Alouatta caraya	Negative
m1338/17	Yes	Cuiabá	Capuchin monkey	Sapajus apella	Negative
m1339/17	Yes	Cuiabá	Sagui	Callithrix sp.	Negative

Federal University of Mato Grosso-Cuiaba.

NA, not available.

Knowledge of the environment surrounding the infected humans or animals, and route of infection and mode of transmission are necessary to understand endemics in certain regions. Truman et al. described that isolates from human and armadillos are identical genetically. Thus, we suggest that the possible contact of animals of this study, which may be possible carriers of the bacillus, with other animals or with humans can disseminate the disease, the bacillus was detected in nasal swabs. Thus, we observe that the detection in wild animals may be associated with high prevalence and endemicity in the state of MT, which makes them important sources of infection. In addition, these data contribute to a better understanding of the epidemiology of leprosy.

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Conflicts of interest

The authors declare no conflicts of interest.