Disseminated Paracoccidioidomycosis in
a Southern Two-Toed Sloth (Choloepus didactylus)
A. Trejo-Cha ´vez*, R. Ramı ´rez-Romero†, J. Ancer-Rodrı ´guez‡,
A. M. Neva ´rez-Garza†and L. E. Rodrı ´guez-Tovar†
*Laboratorio Central Regional de Monterrey, Comite´para el Fomento y Proteccio´n Pecuaria del Estado de Nuevo Leo´n, A.C.,
Terrenos de la Exposicio´n Ganadera, Ciudad Guadalupe, Nuevo Leo´n,†Cuerpo Acade´mico de Patobiologı´a, Facultad de
Medicina Veterinaria y Zootecnia, Universidad Auto´noma de Nuevo Leo´n, Calle Francisco Villa s/n. Escobedo, Nuevo Leo´n
and‡Departamento de Anatomı´a Patolo´gica, Hospital Universitario, Universidad Auto´noma de Nuevo Leo´n, Mexico
A Southern two-toed sloth (Choloepus didactylus), originally acquired from French Guiana, died while main-
tained in quarantine in a pet store in Monterrey, Mexico. Large yeast cells with multiple buds compatible
with Paracoccidioides brasiliensis were observed in disseminated granulomatous lesions in the lungs, liver, spleen
paracoccidioidomycosis in a two-toed sloth.
? 2010 Elsevier Ltd. All rights reserved.
Keywords: granulomatous inflammation; paracoccidioidomycosis; two-toed sloth
Paracoccidioidomycosis (South American blastomy-
cosis) is a chronic and severe systemic granulomatous
disease of people and rarely of animals, caused by the
dimorphic fungus Paracoccidioides
(Brummer et al., 1993; Laniado-Laborı´n, 2007).
The fungus is considered a sapronotic agent with
two different biological behaviours: saprophytic (in
an abiotic substrate at ambient temperature) and
a homeotherm vertebrate host) (Huba ´ lek, 2003).
In man the organism commonly causes a primary
pulmonary infection that is usually inapparent, but
under certain conditions may disseminate to form ul-
cerative granulomata of the oral, nasal and occasion-
ally the gastrointestinal mucosa, the adrenal glands
and the central nervous system (de Almeida, 2005;
Agudelo et al., 2009). Paracoccidioidomycosis may
be treated with trimethoprimesulphamethoxazole,
but in severe cases with disseminated lesions
amphotericin B has been employed successfully.
Mayayo etal., 2007;
Most recently, imidazole derivatives have shown
efficacy (Brummer et al., 1993; Laniado-Laborı´n,
2007). Subclinical infections are common in healthy
residents of areas where the disease is endemic.
Paracoccidioidomycosis is frequently diagnosed in
(Brummer et al., 1993; Laniado-Laborı´n, 2007).
Natural disease in animals has been reported in
a South American squirrel monkey (Saimiri sciureus),
a nine-banded armadillo (Dasypus novemcinctus) and
a dog (Johnson and Lang, 1977; Bagagli et al., 1998;
Ricci et al., 2004). Experimentally, the disease has
been induced in laboratory animals including mice,
rats, guinea pigs, hamsters and dogs, as well as in
armadillos and wild rodents (Brummer et al., 1993;
Ono et al., 2003; Eisele et al., 2004; Nishikaku et al.,
armadillo (D. novemcinctus) is the most susceptible
species and probably acts as a reservoir of the
infection (Bagagli et al., 1998; Nishikaku et al., 2008).
A 5-year-old male Southern two-toed sloth (Choloe-
pus didactylus) was in quarantine in a pet store in Mon-
terrey, Mexico. The animal was imported from
French Guiana. Within a month the animal became
Correspondence to: L. E. Rodrı´guez-Tovar (e-mail: ledgart@hotmail.
0021-9975/$ - see front matter
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J. Comp. Path. 2011, Vol. 144, 231e234
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progressively lethargic, anorectic, dehydrated and
died. The animal did not receive any medical treat-
ment and no laboratory analyses were carried out.
At necropsy examination, numerous firm white
granuloma-like lesions, 1e3 cm in diameter, were
randomly distributed in the lungs, liver, spleen and
kidneys. Samples collected from these organs were
fixed in 10% neutral buffered formalin, processed
routinely and embedded in paraffin wax. Sections
(4 mm) were stained with haematoxylin and eosin
(HE), periodic acideSchiff (PAS) and Grocott’s
modification of Gomori’s periodic acidemethen-
amine silver method for fungal elements.
Microscopical lesions in the lungs consisted of areas
of consolidation formed of aggregates of epithelioid
macrophages admixed with neutrophils and numer-
ous lymphocytes surrounding numerous yeast cells.
The yeast cells were large, round to oval and thick
walled and sometimes appeared to bud at the periph-
ery, giving a characteristic ‘ship’s wheel’ or ‘Mickey’s
cap’ pattern (Fig. 1). There was alveolar thickening
due to interstitial infiltration of neutrophils and the
alveolar spaces contained vacuolated macrophages.
ulomatous lesions associated with the same yeast cells
as seen in the lungs. In the spleen there were numer-
ous epithelioid cells surrounding similar fungal ele-
ments, whereas in the kidneys there were discrete
necrotic foci. The yeast cells stained positive with
PAS and Grocott’s methenamine silver (Figs. 1, 2).
Transmission electron microscopy (TEM) was car-
ried out on the formalin-fixed paraffin wax-embed-
ded samples of lung, liver and spleen. Briefly, the
samples were dewaxed, rehydrated, post-fixed in
medium. Ultrathin sections (60e80 nm) were stained
with uranyl acetate and lead citrate, and examined in
a Zeiss EM 900 transmission electron microscope.
12? 3 mmin diameter,werecontainedwithinmacro-
phage phagosomes. These yeast cells showed superfi-
cial folding of the cell wall. The cell wall was mostly
well defined, fibrillar and thick (electron-dense)
with a wide periplasmic space that limited the cell
membrane. Internally, several swollen mitochondria
and many fused lipid vacuoles were observed
(Fig. 3). In addition, some of these degenerate yeast
cells displayed poorly defined electron-lucent granu-
lar material interpreted as the remnants of endoplas-
mic reticulum. The ultrastructural images were
consistent with previous reports of P. brasiliensis local-
ized inside activated macrophages (Brummer et al.,
These microscopical and ultrastructural findings
were suggestive of paracoccidioidomycosis. Others
have employed specific antibodies against a 43 kDa
glycoprotein (gp43) for immunohistochemical diag-
nosis of the infection (Ricci et al., 2004); however,
this area of diagnosis is still underdeveloped and not
routinely available (Dı´ez et al., 2002).
To our knowledge, this is the first case of paracoc-
thermore, represents the first case of the disease in
animals in Mexico. The sloth was almost certainly
Fig. 1. Liver. There is a cluster of fungi contained within multinu-
space. Budding is noticeable with formation of the conspic-
a lymphoplasmacytic infiltrate enmeshed in fibrous con-
nective tissue surrounds the fungi. PAS. Bar, 20 mm.
of an asymmetric ‘ship’s wheel’ (arrow). There are also
multiple empty and degenerate fungal structures. Grocott.
Bar, 20 mm.
A. Trejo-Cha ´vez et al.
ico, although French Guiana is not considered to be
a country endemic for the disease and the first report
was an imported case in an immigrant from Brazil
(Sarazin et al., 2005).
Underlying compromise of immune function has
not yet been identified in cases of paracoccidioidomy-
cosis in animals. However, it is known that the arma-
dillo does not have strong cell-mediated immune
function, and this may underlie the role of this species
as a reservoir of the fungus (Bagagli et al., 1998;
Nishikaku et al., 2008). In the present case it is
possible that the stress associated with capture and
transport led to depressed immune function that
weakened the resistance of the animal and provoked
the recrudescence of P. brasiliensis infection. The first
6 months in captivity are considered critical for the
survival of sloths (Diniz and Oliveira, 1999). Other
protozoal and fungal infections have been docu-
mented in apparently healthy two-toed sloths (C. di-
braziliensis, Pneumocystis carinii, Histoplasma capsulatum
and Trypanosoma spp. (Diniz and Oliveira, 1999;
Gilmore et al., 2001). A fatal case of toxoplasmosis
has also been reported (Shaw and Lainson, 1973)
and now, based on the present report, paracoccidioi-
domycosis must be considered as a cause of disease
and death of these animals.
including infectionswith Leishmania
The authors gratefully thank J.-J. Araujo-Martı´nez
and H. Solano-Va ´ zquez for providing the case. We
also acknowledge the technical personnel at Labora-
torio de Anatomı´a Patolo ´ gica, Hospital Universi-
tario, UANL, for special stains and Dr C. Cedillo-
Pela ´ ez at Microscopı´a Electro ´ nica FMVZ, UNAM,
for assistance with the TEM study. This work was
supported in part by a PIFI 3.3 SEP budget to im-
prove the status of CA UANL 189 Patobiologı´a.
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Fig. 3. Lung. A partially degenerate yeast cell is contained inside
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Received, April 27th, 2010
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