02774nas a2200289 4500000000100000008004100001653001300042653001100055653002700066653001400093653001200107653001500119100001300134700001200147700001200159700001800171700001700189700001000206700001000216700001300226700001400239700001300253700001400266245008700280520210300367022001402470 2018 d10aZoonosis10aStrain10aPathological variation10aM. leprae10aleprosy10aArmadillos1 aSharma R1 aSingh P1 aPena MT1 aSubramanian R1 aChouljenko V1 aKim J1 aKim N1 aCaskey J1 aBaudena M1 aAdams LW1 aTruman RW00aDifferential growth of Mycobacterium leprae strains (SNP genotypes) in armadillos.3 a
Leprosy (Hansen's Disease) has occurred throughout human history, and persists today at a low prevalence in most populations. Caused by Mycobacterium leprae, the infection primarily involves the skin, mucosa and peripheral nerves. The susceptible host range for Mycobacterium leprae is quite narrow. Besides humans, nine banded armadillos (Dasypus novemcinctus) and red squirrels (Sciurus vulgaris) are the only other natural hosts for M. leprae, but only armadillos recapitulate the disease as seen in humans. Armadillos across the Southern United States harbor a single predominant genotypic strain (SNP Type-3I) of M. leprae, which is also implicated in the zoonotic transmission of leprosy. We investigated, whether the zoonotic strain (3I) has any notable growth advantages in armadillos over another genetically distant strain-type (SNP Type-4P) of M. leprae, and if M. leprae strains manifest any notably different pathology among armadillos. We co-infected armadillos (n = 6) with 2 × 10 highly viable M. leprae of both strains and assessed the relative growth and dissemination of each strain in the animals. We also analyzed 12 additional armadillos, 6 each individually infected with the same quantity of either strain. The infections were allowed to fulminate and the clinical manifestations of the disease were noted. Animals were humanely sacrificed at the terminal stage of infection and the number of bacilli per gram of liver, spleen and lymph node tissue were enumerated by Q-PCR assay. The growth of M. leprae strain 4P was significantly higher (P < 0.05) than 3I when each strain was propagated individually in armadillos. Significantly (P < 0.0001) higher growth of the 4P strain also was confirmed among animals co-infected with both 3I and 4P strain types using whole genome sequencing. Interestingly, the zoonotic strain does not exhibit any growth advantage in these non-human hosts, but the varied proliferation of the two M. leprae strains within armadillos suggest there are notable pathological variations between M. leprae strain-types.
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