AmericanSociety ofMammalogists

Journal of Mammalogy

CONSEQUENCES OF EXPOSURE TO LEPROSY IN APOPULATION OF WILD NINE-BANDED ARMADILLOS

RACHEL E. MORGAN AND W. J. LOUGHRY*

Department of Biology, Valdosta State University, Valdosta, GA 31698-0015, USA

CONSEQUENCES OF EXPOSURE TO LEPROSY IN APOPULATION OF WILD NINE-BANDED ARMADILLOS

RACHEL E. MORGAN AND W. J. LOUGHRY*

Department of Biology, Valdosta State University, Valdosta, GA 31698-0015, USA

Nine-banded armadillos (Dasypus novemcinctus) are the only free-ranging vertebrates other than humans

known to exhibit naturally occurring infections of Mycobacterium leprae, the causative agent of leprosy, but

little is known about ecological consequences of leprosy in wild populations. We studied a population of

armadillos in western Mississippi during the summers of 2007 and 2008. Consistent with previous work, we

found no evidence of leprosy in juveniles or yearlings, suggesting no vertical transmission of disease. In 2008, a

higher proportion of adult females were leprosy-positive than were adult males. Across both years, leprous

females were significantly larger than nonleprous females, but a higher proportion of leprous females were

lactating and lactating females were larger than nonlactating females. The behavior of leprosy-positive and

leprosy-negative animals did not differ. Leprosy-positive individuals tended to be spatially clumped, but these

results were not statistically significant. Our findings suggest leprosy had minimal impacts on individuals in this

population of armadillos, which is a surprising and unexpected result given the substantial costs of infection

documented in the laboratory.

Key words: armadillos, Dasypus novemcinctus, disease ecology, leprosy, Mycobacterium leprae

Aside from humans, the nine-banded armadillo (Dasypusnovemcinctus; hereafter, armadillo) is the only other free-

ranging vertebrate known to exhibit naturally occurring

infections of Mycobacterium leprae, the causative agent in

producing leprosy (Truman 2008). Current molecular evi-

dence suggests that armadillos were 1st exposed to leprosy

within the last 500 years as Europeans and their African slaves

colonized the Americas (Monot et al. 2005). Theory predicts

that pathogens sharing a long coevolutionary history with their

hosts may have small effects on host fitness, whereas newly

introduced pathogens may hinder hosts to a much greater

extent (Frank 1994; Taylor et al. 2006). The recent exposure

of armadillos to leprosy thus leads to the expectation that

infected animals may suffer substantial costs. Consistent with

this prediction, leprous armadillos showed an increase of

23.9% above normal in their basal metabolic rate (Steuber

2007). Armadillos have one of the lowest metabolic rates

reported for any placental mammal (McNab 1980), so this cost

of infection may represent a significant impact on them.

As the primary animal model for leprosy, there have been

numerous laboratory-based studies of infection in armadillos

(reviewed in Truman 2008). In addition to the metabolic costs

described above, these studies have documented other physio-

logical consequences of infection. In contrast, much less

information is available on the impacts of leprosy in wild

populations of armadillos. To date, most field studies have been

largely limited to surveys of disease prevalence (reviewed in

Truman 2008; see also Loughry et al. 2009). Two notable

exceptions include Truman et al. (1991), who reported that all

infected armadillos they sampled were adults, with no sex-

related differences in the likelihood of infection, and Paige et al.

(2002), who were able to calculate an incidence density estimate

using mark–recapture data. However, this latter study was

limited to a rather small number of resampled animals (n 5 23)

and was conducted over a relatively short time frame (minimum

of 21 days between 1st and 2nd capture, with all sampling

completed within the summer of 1997). Thus, we still lack

detailed, long-term data on the potential consequences of

leprosy infection in wild armadillos.

In the present study, we conducted a preliminary analysis of

the ecology of leprosy in wild armadillos. Data were collected

over 2 years from a population in western Mississippi

exhibiting moderate levels of prevalence (,7–12%—Loughry

et al. 2009). We examined demographic and spatial patterns of

leprosy occurrence as well as potential impacts of leprosy on

individual animals. Regarding the latter, the elevated metab-

olism associated with leprosy infection led us to predict that,

compared to nonleprous animals, leprosy-positive armadillos

would be smaller, less active, and have time budgets more

* Correspondent: jloughry@valdosta.edu

E 2009 American Society of Mammalogistswww.mammalogy.org

Journal of Mammalogy, 90(6):1363–1369, 2009

1363

dominated by feeding. Our results represent the 1st detailed

account of the consequences of leprosy in a wild population of

armadillos and provide a starting point for further such studies.

MATERIALS AND METHODS

Study species.—Nine-banded armadillos are medium-sized

(,4 kg adult body weight), burrowing mammals found

throughout much of the southern United States (Aguiar and

Fonseca 2008; Taulman and Robbins 1996). Adults are

usually solitary and mostly active at night (Layne and Glover

1978, 1985; McDonough and Loughry 1997a). Mating occurs

in the summer (McDonough 1997), but females delay

implantation of the fertilized egg until late fall or early winter

(Peppler 2008). Young are born in early spring and typically

1st come above ground between May and July. Littermates are

more social than adults, sharing burrows and foraging

together, but litters appear to break up by fall, perhaps due

to dispersal or mortality (Loughry and McDonough 2001;

McDonough and Loughry 1997b).

Study site.—Data were collected from 14 May to 13 July

2007 and 20 May to 19 July 2008 at the Yazoo National

Wildlife Refuge, Hollandale, Mississippi (33u059N, 90u599W).

Sampling protocol.—Basic methods for capturing live

animals followed previously published protocols (McDonough

and Loughry 2005). These procedures were consistent with

guidelines approved by the American Society of Mammalo-

gists (Gannon et al. 2007) and were approved by Valdosta

State University’s Animal Care and Use Committee (IACUC

number 13-2007). When caught, armadillos were weighed and

the length of the front carapace, front band, back band, and tail

were measured, along with the circumference of the tail base

(Loughry and McDonough 1996). Following Loughry et al.

(2002), the amount of phenotypic damage (e.g., scarring, tail

loss, etc.) also was determined. Lactation status of females

was recorded as definitely lactating, possibly lactating, or

definitely not lactating based on the size and appearance of the

nipples (Loughry and McDonough 1996). Armadillos were

permanently marked with a passive induced transponder tag

injected under the front carapace and for short-term identifi-

cation with reflective tape glued to the carapace. During a

field season, animals were recaptured if they needed new tape,

but they were not measured or weighed again.

To determine leprosy status, the end of 1 toenail was clipped

and blood was collected onto a Nobuto strip (Advantec, Dublin,

California). Blood samples were collected at initial capture each

year but not during any recaptures within a year. These samples

were then screened following previously published protocols

(e.g., Loughry et al. 2009) in the laboratory of Dr. Richard

Truman, National Hansen’s Disease Program, Louisiana State

University. Results of serological screening indicated which

animals had been exposed to M. leprae and mounted a

subsequent immune response, but could not identify the extent

of current infection. Consequently, in what follows we refer to

animals as leprosy-positive (leprous) or leprosy-negative

(nonleprous) rather than as infected or noninfected.

Behavioral data.—Behavioral data were collected in 2

complementary ways (Ancona 2009) to provide information

on the time budgets of leprosy-positive and leprosy-negative

armadillos. First, during nightly censuses to capture armadillos,

instantaneous samples were recorded at 1st sighting of each

animal. This method had the advantage of sampling a large

number of animals multiple times, but did not provide much

detail about the time budgets of particular individuals. Data were

obtained for all animals observed (including unmarked individ-

uals); however, we only used data from known individuals in the

analyses reported here. Second, more detailed time budget data

(albeit from fewer individuals) were obtained by collecting 10-

min focal animal observations with a handheld personal digital

assistant (Palm Treo, Palm, Sunnyvale, California), using

custom-designed data acquisition software that provided the

total number of times a behavior was observed as well as the

total duration of time (in seconds) spent in each behavior.

Because many sessions did not last the full 10 min, all data were

transformed to percentages of total time observed for analysis.

We arbitrarily decided that the minimum duration of a focal

sample for inclusion in the data set was 3.0 min. However, for

the analyses reported here, focal durations were actually much

longer than this (average duration for leprosy-positive animals

5 495.10 s 6 115.59 SD; leprosy-negative animals 5 474.03 6

127.59 s; n 5 10 and 84, respectively). A full list and definitions

of the behaviors observed is provided in Ancona (2009). As with

the instantaneous samples, we only analyzed data from known

individuals. Multiple observations of these individuals were

averaged into a single value for each year, but not between years

because infection status could change.

Spatial data.—Global positioning system coordinates were

collected at the site of initial capture and for each subsequent

sighting of marked individuals. These data were used to

determine the distances animals moved between successive

sightings to test the idea that leprosy-positive animals might

be less active and therefore seen less frequently and move

shorter distances.

Global positioning system data also were used to examine

the spatial distribution of leprosy in the population. We 1st

averaged the coordinates for all sightings of each animal

within each year of the study. We then calculated the distance

of each animal (within each year) to the nearest leprosy-

positive and leprosy-negative armadillo, and the number of

positive and negative animals that were within 200 m (the

typical diameter of a home range—Loughry and McDonough

1998) of each individual. Numbers of leprosy-positive and

-negative animals within 200 m were calculated as proportions

of each type of individual available in the population that year.

Data analyses.—Demographic patterns of infection were

analyzed with contingency tests to determine if certain age or

sex groups were more likely to be leprosy-positive. As

described below, we found no evidence of leprosy in juvenile

or yearling animals, so all subsequent analyses focused strictly

on data from adults.

Unpaired t-tests were used to compare body-size measures of

leprosy-positive and leprosy-negative individuals. These analy-

1364 JOURNAL OF MAMMALOGY Vol. 90, No. 6

ses were done separately for males and females. However, we

found no evidence of differences between years, so data within

each sex were pooled across both years of the study. In females,

we used a 2-way analysis of variance (ANOVA) to examine

variation in body size due to leprosy status and lactation status.

Analyses of instantaneous behavioral samples were done

separately for males and females but, because of small

samples sizes, analyses of focal data were pooled across sexes.

Instantaneous samples were compiled as proportions of

individuals engaged in each behavior and analyzed with

contingency tests. Focal data were analyzed using standard

parametric tests. In both cases, data were pooled across both

years of the study.

Spatial data were analyzed with t-tests to compare the

number of sightings and distances moved between successive

sightings between leprosy-positive and leprosy-negative

animals, the distance of each positive and negative animal to

the nearest other positive and negative armadillo, and the

number of positive and negative animals that were within

200 m of each individual. Note that although data for these

analyses were compiled within each year separately, the

analyses used the data from both years combined.

RESULTS

Patterns of infection.—No juvenile or yearling animals

tested positive for leprosy, leading to a highly significant age

difference in leprosy prevalence (data from both years

combined, x2 5 11.03, d.f. 5 2, P , 0.001; Table 1). A

significantly higher proportion of adult females tested positive

for leprosy in 2008 than did adult males (Fisher’s exact test, P5 0.03) and when data from both years were combined (P 5

0.05; Table 1). Finally, among adult females, a significantly

higher proportion of leprosy-positive females were lactating

than were leprosy-negative females in 2008 (x2 5 8.66, d.f. 5

2, P 5 0.01) and across both years combined (x2 5 9.94, d.f.5 2, P 5 0.007; Table 1).

Although not analyzed statistically, some data were

available on the time course of infection. Of 179 animals

captured in 2008, 53 were recaptures from previous years

(2005–2007). Thirteen of these animals tested positive for

leprosy. Four had tested positive in 2007 and thus had

survived for at least 1 year since exposure. Of the remaining 9,

6 were animals that had tested negative in 2007. The final 3

animals were not captured in 2007 but had tested negative

during earlier sampling in 2005 (2 animals) and 2006 (1

animal). Overall, examination of these data suggests a fairly

rapid and substantial spread of leprosy among resident animals

in this population.

Body size.—There were no significant differences in body

size between leprosy-positive and leprosy-negative males

(Table 2). However, positive males exhibited significantly

more phenotypic damage than did negative males (t 5 3.05,

d.f. 5 127, P 5 0.003; Table 2).

Leprous females were significantly larger than nonleprous

females in the front carapace, back band, and tail base (t-tests,

all P , 0.04; Table 2). However, this seemed to be largely a

consequence of the fact that most leprous females were

lactating and lactating females were larger than nonlactating

females (Table 3). Results of 2-way ANOVA comparisons of

body size showed a significant effect for lactational status, but

not leprosy status, for weight and tail base (both P , 0.05),

although leprosy status, and not lactational status, did generate

a significant difference in front carapace length (P 5 0.04;

there were no significant interaction effects in any compar-

ison).

Behavior.—No significant differences were found in the

behavior of leprosy-positive versus leprosy-negative animals

using either instantaneous samples (Fisher’s exact tests, all P

TABLE 1.—Demography of leprosy prevalence among nine-banded

armadillos (Dasypus novemcinctus) at Yazoo National Wildlife

Refuge in 2007 and 2008.

2007 2008

Leprous Nonleprous Leprous Nonleprous

Adult males 5 55 5 52

Adult females 6 51 16 52

Lactating 4 24 11 20

Not lactating 1 23 2 28

Possibly lactating 1 4 3 4

Yearling males 0 3 0 11

Yearling females 0 5 0 4

Juvenile males 0 10 0 22

Juvenile females 0 3 0 17

TABLE 2.—Differences in body size and extent of phenotypic damage between leprosy-positive and leprosy-negative adult male and female

nine-banded armadillos (Dasypus novemcinctus) at Yazoo National Wildlife Refuge. Data are reported as means 6 SD and were pooled across

both years of the study.

Males Females

Leprous (n 5 10) Nonleprous (n 5 107) Leprous (n 5 22) Nonleprous (n 5 103)

Weight (kg) 4.35 6 0.26 4.19 6 0.39 4.20 6 0.36 4.03 6 0.42

Front carapace length (cm) 21.32 6 0.87 20.85 6 0.83 21.06 6 0.84 20.54 6 0.72

Front band length (cm) 33.03 6 1.31 32.77 6 1.20 33.05 6 1.50 32.59 6 1.23

Back band length (cm) 36.93 6 1.13 36.44 6 1.32 37.12 6 1.52 36.44 6 1.36

Tail base circumference (cm) 15.67 6 0.56 15.62 6 0.68 15.76 6 0.53 15.45 6 0.62

Tail length (cm) 31.26 6 2.13 32.05 6 1.89 32.15 6 1.86 31.84 6 2.22

Damage 6.46 6 4.32 3.18 6 3.32 3.63 6 3.06 3.04 6 3.64

December 2009 MORGAN AND LOUGHRY—ECOLOGY OF LEPROSY IN ARMADILLOS 1365

. 0.18; Table 4) or focal data (t-tests, all P . 0.10; Table 5).

Similarly, there were no significant differences in the number

of sightings per year or distance moved between sightings for

leprous versus nonleprous individuals (t-tests, all P . 0.28;

Table 6). Note that for males, movements between years were

not analyzed statistically because of the small sample size for

leprous males. Likewise, small sample sizes prevented

analyses of movements of females as a function of lactation

status.

Spatial patterns.—Visual inspection of the distribution of

leprous and nonleprous individuals seemed to suggest a

clumped pattern of infection (Fig. 1). However, this was not

borne out statistically, because leprosy-positive and leprosy-

negative animals were equally close to other positive and

negative individuals and had similar proportions of these

individuals within 200 m of them (t-tests, all P . 0.09;

Table 7).

DISCUSSION

Previous laboratory studies have shown that nine-banded

armadillos infected with M. leprae suffer major physiological

costs (Steuber 2007; Truman 2008). It seems logical to assume

these costs should have ramifications for infected animals in

the wild, for example, by limiting their participation in

energetically expensive activities such as reproduction and

long-range movement. Surprisingly, our study provides little

support for this prediction. In general, we found few

differences in the behavior or morphology of leprous versus

nonleprous armadillos and the few significant effects uncov-

ered were in the opposite direction of those predicted. Thus,

examination of our field data suggests that leprosy had few

ecological consequences in this population of armadillos.

However, we would temper this assertion by cautioning that

our serological data did not allow us to identify the severity of

infection in leprosy-positive animals. Thus, it remains possible

that the costs of leprosy are more pronounced (and more

detectable in the field) in animals suffering a full-blown, late-

stage infection.

Not all our results ran counter to expectation. Consistent

with other reports (Truman et al. 1991), we found no evidence

of leprosy in young armadillos (juveniles and yearlings). Thus,

it appears there was no vertical transmission of disease.

However, leprosy is slow-acting and so the possibility exists

that young animals might be infected but not manifest any

detectable signs of infection until later in life. Definitive data

from long-term longitudinal studies will be required to

ultimately determine the potential for vertical transmission

of leprosy.

Examination of our data showed that leprosy-positive adult

males had more phenotypic damage than did leprosy-negative

males and that more positive females were lactating than were

negative females. Truman et al. (1991) showed that proges-

TABLE 3.—Differences in body size and extent of phenotypic damage between leprosy-positive and leprosy-negative adult female nine-banded

armadillos (Dasypus novemcinctus) of differing lactational status at Yazoo National Wildlife Refuge. Data are reported as means 6 SD and were

pooled across both years of the study. Sample sizes are available in Table 1.

Leprosy-positive Leprosy-negative

Lactating Not lactating Possibly lactating Lactating Not lactating Possibly lactating

Weight (kg) 4.30 6 0.35 3.81 6 0.21 4.08 6 0.24 4.09 6 0.40 3.93 6 0.42 4.19 6 0.43

Front carapace length (cm) 21.10 6 0.87 20.80 6 0.70 21.10 6 1.06 20.56 6 0.76 20.54 6 0.71 20.45 6 0.66

Front band length (cm) 33.29 6 1.54 31.90 6 0.99 33.03 6 1.64 32.72 6 1.22 32.52 6 1.24 32.50 6 1.32

Back band length (cm) 37.38 6 1.52 36.47 6 1.86 36.47 6 1.23 36.73 6 1.38 36.26 6 1.32 36.17 6 1.37

Tail base circumference (cm) 15.93 6 0.53 15.13 6 0.12 15.53 6 0.08 15.58 6 0.64 15.35 6 0.61 15.44 6 0.52

Tail length (cm) 32.31 6 1.97 32.63 6 2.04 30.90 6 0.56 31.09 6 2.09 32.27 6 2.26 32.42 6 1.91

Damage 3.88 6 3.12 1.67 6 1.53 4.33 6 4.04 3.24 6 3.60 2.81 6 3.56 3.30 6 4.22

TABLE 4.—Behavioral differences between leprosy-positive and

leprosy-negative adult male and female nine-banded armadillos

(Dasypus novemcinctus) at Yazoo National Wildlife Refuge using

instantaneous samples. Data are reported as the number of individuals

observed. Data were pooled across both years of the study.

Males Females

Behavior Leprous Nonleprous Leprous Nonleprous

Bipedal sniff — 1 — 1

Chase — — — 1

Dig — — — 1

Feed 22 155 33 201

Mate — 9 1 13

Pause — 2 1 2

Run — 1 — 1

Walk 2 27 2 18

TABLE 5.—Differences in time allocation between leprosy-positive

and leprosy-negative nine-banded armadillos (Dasypus novemcinctus)

at Yazoo National Wildlife Refuge using focal animal observations.

Data are reported as the mean 6 SD percentage of time spent in each

behavior. Data were averaged for each individual within each year

but were pooled across both years of the study. Behaviors that

occurred rarely are not presented and were not analyzed statistically.

Behavior Leprous (n 5 10) Nonleprous (n 5 84)

Bipedal sniff 1.22 6 1.37 0.85 6 1.52

Chase 0.00 6 0.00 0.02 6 0.16

Feed 94.19 6 8.73 90.26 6 10.96

Mate 0.00 6 0.00 0.22 6 1.30

Pause 0.98 6 1.12 2.43 6 2.75

Run 0.69 6 1.17 0.80 6 3.20

1366 JOURNAL OF MAMMALOGY Vol. 90, No. 6

terone levels correlated with weight and that infected female

armadillos had higher progesterone levels than uninfected

females. Thus, leprosy infection was more common among

large, lactating females, similar to what we found here. Other

studies indicate that the extent of phenotypic damage is

correlated with age (Loughry et al. 2002) and that lactating

females are older than nonlactating females (McDonough

1997). Thus, our results indicate that not only is leprosy a

disease of adult armadillos, but a disease of old adults.

The transmission dynamics of leprosy in wild armadillos are

still unknown; one critical issue for future studies will be to

determine how older armadillos acquire the disease. The high

incidence density calculated by Paige et al. (2002) and our

data documenting new infection in 9 of 53 recaptured animals

suggest that infection can be acquired rapidly. Although not

significant, spatial trends in our data pointed toward possible

clumping of leprosy within our population (Fig. 1). Such

clumping might reflect interactions with leprous animals that

facilitate transmission (Scholl et al. 1995) or specific

ecological conditions that enhance exposure to M. leprae(Truman 1996, 2005).

Contrary to other studies (e.g., Truman et al. 1991), we

found that a higher proportion of females tested positive for

leprosy than did males, as did lactating females versus other

females. The latter result is particularly remarkable and

indicates that leprous females could bear the costs of

reproduction despite the substantial increase in metabolism

associated with leprosy (Steuber 2007). How leprous females

are able to do this is currently unknown. It may be that females

increase reproductive effort, but our data provide little support

for this idea because we could find no behavioral differences

between leprosy-positive and leprosy-negative individuals. In

TABLE 6.—Differences in number of sightings per year and distances moved between successive sightings for leprosy-positive and leprosy-

negative adult male and female nine-banded armadillos (Dasypus novemcinctus) at Yazoo National Wildlife Refuge. Data are reported as means

6 SD and were pooled across both years of the study.

Males Females

Leprous Nonleprous Leprous Nonleprous

Number of sightings 2.50 6 2.12 (n 5 10) 1.95 6 1.55 (n 5 105) 1.81 6 1.08 (n 5 22) 2.37 6 2.65 (n 5 105)

Distance moved between successive

sightings within a year (m) 202.66 6 105.20 (n 5 5) 140.11 6 124.35 (n 5 50) 127.08 6 130.29 (n 5 10) 132.66 6 97.51 (n 5 48)

Distance moved between successive

sightings between years (m) 646.46 (n 5 1) 268.93 6 258.91 (n 5 23) 174.19 6 130.27 (n 5 12) 177.55 6 120.20 (n 5 18)

FIG. 1.—Spatial locations of leprosy-positive (n 5 32) and leprosy-negative (n 5 210) adult nine-banded armadillos (Dasypus novemcinctus)

at Yazoo National Wildlife Refuge. Points represent the average of all global positioning system coordinates obtained for each animal in each

year of the study.

December 2009 MORGAN AND LOUGHRY—ECOLOGY OF LEPROSY IN ARMADILLOS 1367

a broader analysis of armadillo time budgets, Ancona (2009)

also found few differences between individuals. However, she

pointed out that differences might still occur, not in terms of

what animals do while active, but rather in how long they

remain active. A similar argument may apply to our data, with

leprous armadillos showing significant differences in the

duration of the active period relative to those exhibited by

nonleprous animals. Testing this hypothesis will require

observing animals for much longer periods of time than we

were able to achieve in this study.

Given that lactating females were larger than other females,

perhaps increased reproductive effort in leprous females is

manifested in increased size or, alternatively, that only large

females are able to withstand the effects of leprosy sufficiently

to survive and reproduce. Either way, it is important to point

out that the fate of reproductive attempts by leprous females

was unknown. If leprosy-positive females failed to produce

many surviving offspring, then, even though many of them

were reproductively active, these leprous females may still

have been less reproductively successful than nonleprous

females.

In males, where lactation status did not play a role, the only

difference found was that leprosy-positive males had more

carapace damage than did leprosy-negative animals. Carapace

damage is not a manifestation of leprosy infection, but rather

typically results from hostile encounters with predators or

conspecifics (Loughry et al. 2002). It is unclear why this

difference in damage occurred in males but not females, but it

could be due to leprous males losing more fights to healthier,

nonleprous males. The reduced prevalence of leprosy in males

relative to females remains difficult to explain and runs

counter to results obtained in other surveys (e.g., Truman et al.

1991). This finding may be an artifact of small sample sizes;

however, studies in other species suggest that such heteroge-

neity may facilitate disease transmission by concentrating

pathogens within those individuals with higher survival or

encounter rates with conspecifics (Adler et al. 2008). Whether

such an argument applies in armadillos remains speculative,

but suggests an important direction for future research.

Our data present the 1st detailed analysis of leprosy’s

impacts in a wild armadillo population and contribute to a

growing body of work documenting life-history impacts of

disease in other mammals (e.g., Lachish et al. 2009).

Nonetheless, we would urge caution in interpreting our results

because the data come from a relatively small number of

leprous animals (n 5 32) sampled over just a 2-year period. As

such, our findings should be regarded as preliminary. Ongoing

study of this population will ultimately provide a more

comprehensive data set that will determine the generality of

the results reported here.

RESUMEN

El armadillo de nueve bandas (Dasypus novemcinctus) es el

unico vertebrado salvaje, que junto con los seres humanos,

exhiben infecciones de Mycobacterium lepare, agente cau-

sante de la lepra; pero poco es lo que se sabe sobre las

consecuencias ecologicas de la lepra en poblaciones salvajes.

Estudiamos poblaciones de armadillos en el oeste de

Mississippi durante los veranos del 2007 y 2008. Consistente

con trabajos previos, no encontramos evidencias de lepra en

juveniles o en individuos de un ano, lo que sugiere que no hay

transmision vertical de la enfermedad. En el 2008, mas

hembras fueron positivas por lepra que machos. Considerando

ambos anos juntos, las hembras leprosas fueron significante-

mente mas grandes que las no leprosas, pero una gran

proporcion de hembras leprosas estaban lactando y hembras

lactando fueron mas grandes que las no lactando. No hubo

diferencias en el comportamiento entre animales leprosos y no

leprosos. Individuos leprosos positivos mostraron una tenden-

cia a estar agrupados espacialmente pero esto no fue

estadısticamente significativo. Nuestros resultados sugieren

que la lepra tiene un impacto mınimo en individuos de esta

poblacion de armadillos, resultado que es sorprendente e

inesperado dado el alto costo fisiologico de esta infeccion

documentada en laboratorios.

ACKNOWLEDGMENTS

We thank the staff of the Yazoo National Wildlife Refuge for their

support of this project. Partial funding for this study came from a

National Geographic grant, Valdosta State University Faculty

Research Awards, and a grant from the Valdosta State University

Center for Applied Research (all to WJL). We are extremely grateful

to J. Ha for creating the behavioral data acquisition software and to K.

Ancona, M. Ard, L. Bernhardt, and B. Spychalski for their assistance

in the field. B. Baggato, C. Brooks, M. Lockhart, C. McDonough, P.

Moore, R. Truman, and 2 anonymous reviewers provided very useful

feedback on earlier drafts of this manuscript. We also thank C. Iudica

for preparing the Spanish summary.

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Submitted 16 December 2008. Accepted 9 April 2009.

Associate Editor was Rodrigo A. Medellın.

December 2009 MORGAN AND LOUGHRY—ECOLOGY OF LEPROSY IN ARMADILLOS 1369