zoonoses and communicable diseases common to ... - PAHO/WHO

150 BACTERIOSESOccurrence in Animals: Natural infection has been found in nine-bandedarmadillos (Dasypus novemcinctus) in Louisiana and Texas (USA) and in Mexico.By 1983, the infection had been observed in some 100 armadillos captured inLouisiana (Meyers et al., 1983). Depending on their place of origin, between 4%and 29.6% of 1,033 armadillos examined were infected. On the Gulf Coast of Texas,leprosy lesions were found in 4.66% of 451 armadillos captured (Smith et al., 1983).The disease form found in these animals was a lepromatous leprosy identical to thetype produced by experimental inoculation with material from humans. On the otherhand, the search for naturally infected armadillos carried out by other researchers inLouisiana, Texas, and Florida, as well as in Colombia and Paraguay, produced negativeresults (Kirchheimer, 1979).At present, natural infection of nine-banded armadillos is a well-established fact.Its distribution is limited to some states in the US and Mexico. In Mexico, 1 of 96armadillos was positive based on histopathology and mouse footpad inoculation(Amezcua et al., 1984). In a study of armadillos found dead on the highways ofLouisiana, 10 of 494 (2%) were positive based on histopathology and pyridineextraction (Job et al., 1986a). The infection was also confirmed in an armadillo atthe San Diego Zoo, California, and in another armadillo at the Centers for DiseaseControl and Prevention. The two armadillos originally came from Texas (Walsh etal., 1981).The ELISA method was adopted for serological study of leprosy in armadillosusing phenolic glycolipid (PGL-1) antigen (Truman et al., 1986), which is consideredspecific for M. leprae (Young and Buchanan, 1983). This test was conductedon armadillos captured in central Louisiana before being used in the laboratory(1960–1964). It was found that 17 of the 182 sera (9.3%) were serologically positive.This study was undertaken to refute the argument that free armadillos couldhave become infected by experimental armadillos through carelessness. The serawere collected at that time for a study on leptospirosis. Of 20 armadillos capturedshortly before this study, four were positive.Another study used ELISA and histopathological tests to examine 77 armadillosin an estimated population of 254 ± 60 animals in a defined area of Louisiana. Fiveof 67 (1.5%) sera tested with ELISA and 1 of 74 (1.3%) ears submitted forhistopathological examination were positive (Stallknecht et al., 1987).On the Texas Gulf Coast, the presence of leprosy in armadillos was demonstrated(Smith et al., 1983). More recently, 237 armadillo ears from 51 central Texas districtswere examined; no positives were found upon histological examination (Clarket al., 1987). A similar negative result was obtained for 853 ears from armadilloskilled on the highways or captured for research purposes in five southeastern USstates. The examination included microscopic and histopathological examination(Howerth et al., 1990). An infected animal had previously been found in the state ofMississippi (Walsh et al., 1986).A spontaneous case of leprosy similar to the borderline or dimorphous form wasdescribed in a chimpanzee imported from Sierra Leone to the United States. Clinicaland histopathologic characteristics (with invasion of dermal nerves by the agent)were identical to those of the human disease. Attempts to culture the bacteria werenegative, and the chimpanzee did not respond to tuberculin or lepromin, just ashumans infected with lepromatous or dimorphous leprosy give a negative reaction.As with M. leprae of human origin, experimental inoculation of rats with the iso-