Carlos Eduardo Larsson
Full professor of Internal Medicine-FMVz/USP, Av. Prof. Dr. Orlando Marques de Paiva
São Paulo, Brasil
PUBLIC HEALTH CONSIDERATIONS
Besides the classical and usual dermatozoonosis(dermatophytosis, canine and feline scabies, otodectic mange, cheyletiellosis, flea bite and hemintic dermatitis) it's been verified a preoccupying growth in the human sporotrichosis cases in Brazil, due to the contact with affected cats.
In Brazil, until the sixties, the human sporotrichosis was the second most common deep mycoses, just after the South American blastomycosis. At the College of Medicine / University of São Paulo, taking into account just the period between 1945-1953, 104 sporotrichosis cases were reported15 which means and average of 13 cases per year. In 1999, according two Brazilian authors14 in the disease incidence was seen similarly to what was happening in the USA, Japan and South Africa. From 1992 to 1998 less than one case per year was seen at the College of Medicine / University of São Paulo14.
However, in the last three years has been observed an intriguingly sporotrichosis outbreak in Rio de Janeiro, a southwest state of Brazil. According to Valle19 (2001), between 1999 and 2000, 66 human cases were diagnosed, mainly in female patients (67%) and a mean age of 41 years. Among these, 52 (79%) patients had frequent contact with cats whereas 31 (47%) mentioned history of scratch or bite.
Schubach et al16 (2000) were able in Rio de Janeiro to confirm the sporotrichosis diagnosis in 119 (73%) among 162 feline patients seen at Fundação Oswaldo Cruz.
Unfortunately, most of the human general physicians and dermatologists do not know or give the proper attention to the role that cats play in sporotrichosis transmission. Frequently, these professionals attribute the infection to the contact with vegetables, soil etc and completely forget the possibility of infection from scratch and bite of diseased cats. Very often the veterinarians also forget a basic rule in veterinary dermatology: "ulcerated skin lesions, in cats, are potentially involved with neoplasia, cryptococcosis or sporotrichosis."
ETIOLOGY AND EPIDEMIOLOGY
The sporotrichosis is a subcutaneous mycosis caused by the dimorphic, nonspecific fungus Sporothrix schenkii, which exists as a saprophyte in soil, vegetables and organic debris. It's been isolated from tree bark, sphagnum moss, conifer seedlings, what probably justify the occurrence of disease in gardeners, farmers, miners, and animal, seedling and flower handlers. The feline habits of digging holes or covering their excrement with soil or sand, and sharpening its nails on tree trunks, are responsible for the carriage of fungus on its claws, even as a healthy host, becoming able to infect other animals and men with Sporothrix. In Brazil, Souza & Mierelles18 (2001) were able to isolate the causative agent from claws of 16,5% of the examined cats, in Rio Grande do Sul. Not only the cat, but also the armadillo (Dasypus novemcinctus), which is permanently in contact with soil, digging holes and galleries, is involved in human transmission of sporotrichosis, in Uruguay8.
In tropical countries, like Brazil and many others in South America, Asia and Africa, is extremely frequent the occurrence of human and animal sporotrichosis. In Brazil, it was already diagnosed in mules, donkeys, chimpanzees, bulls, rats, dogs and cats8. The largest amount of feline sporotrichosis cases found in literature is from Freitas et al.3 (1965), describing eight cases in São Paulo (Brazil), and from Schubach et al16 (2001) that recently reported 119 feline cases in Rio de Janeiro (Brazil).
The first report relating sporotrichosis transmission from cat to man is from 1955, published by Brazilian physicians1. We could find, at international literature, papers from Read & Sperling12 (1982); Nusbaum et al.11 (1983); Dunstam et al.2 (1986); Zamri-Saad et al.20 (1990); Larsson et al.8 (1989); Larsson et al.7 (1996). The sporotrichosis is much more frequent among cats in comparison to dogs. At the Dermatological Service of Veterinary Hospital of Faculdade de Medicina Veterinária da Universidade de São Paulo, it was diagnosed about 30 cases in cats and only three in dogs, over a 12 - year period (1986-1997)6. Among these 30 cats, 21 were males (70%), had domestic habits or free access to outside, showing a major risk of infection by animal with no restriction or limited households. Seventy per cent was one to three years old (20%-4 to 6 years old; 10%-7 to 10 years old), and 25 (83,3%) were mixbreed6.
The cutaneous form is the most commonly reported among cats and dogs, mainly the fixed and cutaneous lymphatic form (dogs). The disseminated form involving bones is uncommon in dogs and cats5,6.
In the cutaneous form, multiple firm nodules are present, developing draining tracts, with ulcerated, verrucous and exudative areas. Generally the lesions are neither painful nor pruritic. The cutaneous lymphatic form is characterized by nodules that come out from the entrance point of the agent (sporotrichotic canker), generally at one limb, with subsequent ascending infection via the lymphatics, generating secondary nodules, that often ulcerate and discharge a purulent exudate. This form is associated with regional lymphadenopathy.
The lesions are commonly seen on the head, distal limbs or tail, which may often resemble the cryptococcosis ones. Initially, the lesions are very similar to those caused by fighting, and are presented as abscesses, draining tracts or cellulitis. Large areas of necrosis, erosion, ulcers and crusts may develop. The disease may spread, mainly if there is improper use of corticosteroid, and may be followed by generalized organic signs like lethargy, depression, anorexia and fever. In cases of disseminated disease, it is important to consider the possibility of an immunosuppressive status. In Brazil the feline-feline leukemia correlativity has been varying from 0 to 22%6,18.
The diagnosis is based on anamnesis data (place and kind of breeding, age, sex, contact with other animals or vegetables, etc), on physical examination and complementary exams (cytology, fungal culture, inoculation in laboratory animals, intradermal reaction, serology and histopathology) "intra-vitam" and "post-mortem." The differential diagnosis includes neoplasia and many deep infection granulomas and pyogranulomas. Among the dermatitis to be differentiated, there can be included demodicosis, pyoderma, panniculitis, mycobacteriosis, histoplasmosis, coccidioidomycosis, cryptococcosis, pheohyphomicosis and mycetoma4,13,17.
1. Almeida, F; Sampaio, S.A.P.; Lacaz, C.S.; Fernandes, J.C. Dados estatísticos sobre a esporotricose - análise de 344 casos. Anais brasileiros de dermatologia e Sifiligrafia.v. 1, p. 9-12, 1955.
2. Dunstam, R.W.; Langham, R.F; Reimann, K.A.; Wakenel, P.S. Feline sporotrichosis: a report of five cases with transmission to humans Journal of American Academy of Dermatology, v. 15, p. 37-45, 1986.
3. Freitas, D.C; Moreno, G; Saliba, A.M.F; Bottino, A.J; Mos, E.N. Esporotricose em cães e gatos Revista Faculdade de Medicina Veterinária da Universidade de São Paulo v.7, p. 381-7, 1965.
4. Gross, T.L.; Ihrke, P.J.; Walder, E.J. Veterinary dermatopathology. S. Louis Mosby, 1992.
5. Iwasaki, M.; Hagiwara, M.K.; Gandra, C.R.P.; Correa, B.; Araújo, N.S. Skeletal sporotrichosis in a dog. Compendium of Animal Practice, v.2, n.5, p. 27-31, 1988.
6. Larsson, C.E.; Criptococose e esporotricose em carnívoros domésticos: aspectos clínicos e tratamento. In: Congresso Brasileiro De Medicina Veterinária, 13, Gramado - RS, Outubro de 1997 Anais.
7. Larsson, C.E.; Otsuka, M.; Michalany, N.S. El gato como fuente de infección en la esporotricosis humana: relato de casos en São Paulo (Brasil) Congresso Panamericano De Ciências Veterinárias, 15, Campo Grande, M.S., Brasil, 21 a 25 de outubro de 1996. Anais.
8. Larsson, C.E; Gonçalves, M.A; Araújo, V.C; Dagli, M.L.Z; Corrêa, B.; Fava Neto, C. Esporotricose felina: aspectos clínicos e zoonóticos. Revista Instituto Medicina Tropical de São Paulo, v. 81, p. 351-8, 1989.
9. Larsson, M.H.M.A. Estudo epidemiológico da escabiose humana causada pelo Sarcoples scabiei var.canis (Bourguignon, 1853) Tese. Faculdade de Saúde Pública-USP, 1976.
10. Muller, G.H; Kirk, R.W; Scott, D.W. Small animal dermatology. 4ª ed. Saunders, Philadelphia, 1989.
11. Nusbaum, B.P.; Gulbas, N.; Horwitz, S.N. Sporotricosis acquired from a cat. Journal of American Academy of Dermatology, v.8, p. 386-91, 1983.
12. Read, S.I. & Sperling, L.C. Feline sporotrichosis acquired from a cat Journal of American Academy. of Dermatology,v. 8, p. 386-91, 1983.
13. Rosser, E.J.; Sporotrichosis and public health. In: KIRK, R.W. (ed). Current veterinary therapy. Philadelphia, Saunders, 1990.
14. Sampaio, S.A.P.; Castro, R.M.; Rivitti, E.A. Dermatologia básica. 2ª ed. Artes Médicas São Paulo, 1982.
15. Sampaio, S.A.P.; Lacaz, C.S.; Almeida, F. Aspectos clínicos da esporotricose em São Paulo. Revista Hospital Clínicas, v. 9, n. 6, p. 391-402, 1954.
16. Schubach, T.M.P.; Okamoto, T.; Pellon, I.V.; Monteiro, D.F.; Melo, M.; Reis, R.S.; Monteiro, P.C.F.; Schubach, A. O gato doméstico - fonte de infecção da esporotricose urbana no Rio de Janeiro. In: Congresso Internacional De Medicina Felina, 2°, Rio de Janeiro, 2001. p. 25.
17. Scott, D.W.; Miller Jr, W.H.; Griffin, C.E. Dermatologia De Pequenos Animais. 5ª Ed., Rio De Janeiro, Interlivros, 1996.
18. Souza, L.L; Meirelles, M.C.A. Sporothrix schenkii: estudo epidemiológico em populações de gatos. Dissertação (Mestrado). Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, 2001, São Paulo, 146 P.
19. Valle, A.C.F. Esporotricose: surto no Rio de Janeiro. Rio Dermatol. SBD-RJ, v.2, p. 6, 2001.
20. Zamri-Saad, M.; Salmiyah, T.S.; Jasni, S.M.; Cheng, B.Y.; Basri, K. Feline sporotrichosis: an increasingly important zoonotic disease in Malaysia. Veterinary Record.,v. 127, p. 480, 1990.
Carlos Eduardo Larsson