Keywords
epidemic - sporotrichosis - zoonotic
Introduction
Sporotrichosis, caused by the dimorphic fungus Sporothrix schenckii was first described by Benjamin Schenck in 1898. It is a subacute or chronic mycosis
that affects all ages.[1] It is currently distributed throughout the world, especially in tropical and subtropical
zone, and is the most common subcutaneous mycosis in Latin America. Infection almost
always occurs by traumatic inoculation of soil, plants, and organic matter contaminated
by fungus. Felines have very close contact with contaminated soil and organic matter
and constitute a reservoir of this agent. An epidemic of zoonotic transmission originating
from infected domestic cats is occurring in Rio de Janeiro, Brazil. We present a case
that exemplifies this problem.
Case Report
A 6-year-old boy presented with erythematous-crusted lesion on the trunk region, which
had been present for 2 months ([Fig. 1A, B]). He gave a history of contact with a sick domestic cat ([Fig. 1C]). An incisional biopsy of the lesion was performed, and histopathologic examination
revealed pseudocarcinomatous hyperplasia and occasional multinucleated giant cells.
Growth of S. schenckii was obtained from culture of the tissue ([Fig. 2A–D]). After confirmation of the diagnosis of sporotrichosis treatment with itraconazole
100 mg/d was commenced, with healing after 3 months. The patient was regularly followed
up after cessation of treatment, and no signs of recurrence were elicited.
Fig. 1 (A) Erythematous crusted lesion on the trunk. (B) The same lesion in more detail.
(C) An affected domestic cat from the sporotrichosis epidemic in Rio de Janeiro, Brazil.
Fig. 2 The dimorphic fungus Sporothrix schenckii, growing: (A and C) as a mycelium at room temperature (25°C), and (B and D) in the
yeast phase (37°C).
Discussion
The outbreak of cat-related sporotrichosis in Rio de Janeiro, Brazil, appears to have
begun in around 1998. Although several cases have been reported in the literature,[1]
[2] the problem is not widely known about internationally. The rise in tourism in Brazil,
particularly in association with major international sporting events, makes it important
that health care practitioners in other countries are aware of this outbreak.
The presentation of sporotrichosis varies according to the virulence of the strain
and host immune status.[3] There is little direct evidence how the infectious agent became disseminated throughout
the Rio de Janeiro municipality and its outskirts, but it is beyond reasonable doubt
that the close interaction with cats represents a key route of transmission of the
fungus to humans.[1]
[2] However, felines have very close contact with contaminated soil and organic matter
that constitute reservoirs of S. schenckii.[4] The gold standard for sporotrichosis diagnosis is culture, and the drug of choice
for treatment is oral itraconazole.[5] Dermatologists and pediatrics must be aware of the possibility of cat-related sporotrichosis
presenting in humans to avoid diagnostic pitfalls.
