SYNONYM OR CROSS REFERENCE: Sporotrichosis, and rose handler’s disease Footnote 3 .
CHARACTERISTICS: Dimorphic fungus found as hyphae with conidia (2 to 3μm in diameter) at 25°C, and in cigar-shaped yeast form (4 to 6μm in diameter) in animal tissues at 37°C Footnote 3, Footnote 4. The organism grows readily on Sabouraud dextrose agar, producing lobulated, cream-coloured, smooth or verrucous, moist colonies with occasional aerial mycelia. After a few days, it matures into a black leathery colony Footnote 5.
PATHOGENICITY/TOXICITY: Sporotrichosis is classified into 4 categories: lymphocutaneous, fixed cutaneous, multifocal or disseminated, and extra-cutaneous form Footnote 5. In all forms, cutaneous lesions usually arise in the limbs. In children, facial lesions are also common in up to 92% of cases. Cutaneous disseminated and systemic sporotrichosis are rare variants, and are almost always associated with immunosuppression of the host Footnote 5.
Lymphocutaneous: This form of the disease is the most frequent variant, representing over 75% of all cases Footnote 5, Footnote 6. It is characterized by the emergence of an indurated papule, approximately 2 to 4 cm in diameter that develops about 7 to 30 days after inoculation of the fungus into the skin. Progressive induration leads to nodule formation with subsequent ulceration. Further nodules appear in the lymph trajectory contiguous to the initial lesion. The lesions tend to soften and may produce cutaneous fistulae. Systemic symptoms, if present, are usually mild. Regional lymphadenopathy is frequently found. The upper and lower limbs are the most commonly affected regions. Bilateral disease is rare and would suggest multiple point inoculation possibly related to the patient’s professional activity. Erythema nodosum may be present Footnote 5, Footnote 7, Footnote 8.
Fixed cutaneous: In some patients, there is no lymphatic dissemination during the course of the disease, with the lesion remaining confined to the site of the initial inoculation. This form is known as fixed cutaneous sporotrichosis. The lesions may be papular, plaque-like, nodular, verrucous, or ulcerated, and can occur in the face, neck, trunk, or legs. Often they become chronic because there is no tendency for spontaneous resolution. Erythema nodosum may also develop Footnote 5-Footnote 7.
Multifocal or disseminated: This form is almost always associated with an immunodeficient or debilitated state, whether from alcoholism, diabetes, sarcoidosis, tuberculosis, organ transplantation, malignancy, use of immunosuppressive agents, or AIDS. The clinical picture is highly variable, with possible ulceration, acneiform lesions, hardened plaques, or crusts. Death usually arises when there is pulmonary or meningeal involvement Footnote 5, Footnote 9.
Extra-cutaneous: It is rare and difficult to diagnose because of the absence of skin lesions. It is caused by inhalation of spores or by haematogenic dissemination from a deep inoculation site. Osteoarticular infection is found in up to 80% of cases Footnote 1. Monoarthritis occurs with oedema, synovial effusion, and limitation of normal function. The hands, wrists, elbows, ankles, and knees are the most frequently affected sites. Tenosynovitis, with or without carpal tunnel syndrome, is associated with deep inoculations. If untreated, the infection will lead to osteomyelitis Footnote 5, Footnote 10, Footnote 11. This form is almost always confined to those whom have major cellular immunodeficiencies.
Pulmonary sporotrichosis tends to affect 30 to 60 year old men with pre-existing co-morbidities. The clinical picture is similar to pulmonary tuberculosis with low-grade fever, weight loss, chronic cough, and unilateral or bilateral pulmonary fibrosis with cavitations. Hilar lymphadenopathy and pleural effusion are also usually present Footnote 5.
Sporotrichotic meningitis is an extremely rare condition that is almost always associated with immunosuppression. Other extracutaneous forms such as ocular or conjunctival, genital and penile sporotrichosis have been described in a rare few cases Footnote 5, Footnote 12, Footnote 13.
Another very rare form, designated as the mucosal form, causes nodules in the nose, mouth, pharynx, larynx, and trachea, and thus may resemble tonsillitis, stomatitis, glossitis, laryngitis, or rhinitis of other origins Footnote 14.
EPIDEMIOLOGY: Reported worldwide. Professional activities associated with infection include gardening, carpentry, agriculture, horticulture, florist, bee keeping, hunting, fishing, animal husbandry, and veterinary practice Footnote 2, Footnote 5, Footnote 10, Footnote 15. In an epidemic in Rio de Janeiro (Brazil) from 1998 to 2001, out of 178 human cases, 68% were women, followed by occupational students (18%), and 5% of the patients were veterinarians Footnote 16, Footnote 17. Sporotrichosis occurs mainly in moist tropical and subtropical zones (Brazil, Colombia, Venezuela, Costa Rica, Guatemala, Mexico, the Mississippi River Delta, Southeast Asia (particularly Indonesia), South Africa, and Australia). In Europe, it has been observed with increasing frequency in Italy, while only sporadic cases have been reported from other countries Footnote 14. It is more frequent in Asia, Brazil, Central America, Mexico, South Africa, and Zimbabwe than in other areas. Although it is a relatively rare disease, an epidemic of sporotrichosis affecting 3,000 workers was recorded in South African gold mines in the early 1940s Footnote 1, Footnote 6.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: S. schenckii is ubiquitous in nature and often found in rotting wood, dead plant materials, surface water, and occasionally, swimming pools Footnote 14. Human and animals almost always become infected through a cutaneous lesion Footnote 1. Transmission occurs through direct contact with the ulcerous lesions or scratches and bites from cats or armadillos Footnote 5, and occasionally dogs and squirrels Footnote 14. Introduction of fungus through the skin occurs as a result of pricks from splinters, thorns or barbs, insect bites, gardening tools, handling of sphagnum moss or slivers from wood or lumber, and bales of hay. Persons handling sick cats are a risk group. The possibility of aerial transmission can not be excluded Footnote 2, Footnote 14.
DRUG SUSCEPTIBILITY: Sensitive to saturated solution of potassium iodide, itraconazole, amphotericin B, ketoconazole, fluconazole Footnote 1, Footnote 3, Footnote 5, Footnote 6, Footnote 18, other triazoles (saperconazole, voriconazole, ravuconazole, and posaconazole) Footnote 1, Footnote 19, and terbinafine Footnote 6, Footnote 20. Some isolates are found to be resistant to amphotericin B Footnote 18.
SUSCEPTIBILITY TO DISINFECTANTS: Sensitive to 70% ethanol, sodium hypochlorite (500 to 1,000 ppm), accelerated hydrogen peroxide (6,000 ppm) Footnote 21-Footnote 23, a mixture of zinc sulphate and triolith Footnote 2, and formaldehyde Footnote 5.
PHYSICAL INACTIVATION: Sensitive to moist heat (121°C for 15 minutes) Footnote 23.
SURVEILLANCE: Diagnosis is based on clinical signs, histology, and/or by culture of biopsy samples and identification. Histological features include epidermal hyperplasia, hyperkeratosis, intradermal abscesses and mixed granulomas with asteroid bodies. Periodic acid-Schiff or Grocott stain reveals a pyogranulomatous response and may show yeast form Footnote 6, Footnote 14. A latex agglutination test is used to detect antibodies. Other serological tests such as precipitation and complement fixation tests, as well as a sporotrichin skin test are diagnostic but can be positive in areas of endemicity in persons without overt signs. The sporotrichin skin test is also positive in less than 90% of proven cases and is positive in cases of previous infection Footnote 6, Footnote 14 and is thus considered unhelpful in clinical diagnosis. Sporotrichosis lesions are often misdiagnosed and require biopsy and/or culture for correct diagnosis and management. A DNA fingerprinting method is used to identify different populations of strains Footnote 24.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Lymphocutaneous and cutaneous sporotrichosis: The classic therapy for this form of sporotrichosis, which has been used since the beginning of the 20th century, is saturated solution of potassium iodide; however, itraconazole has become the drug of choice. The success rate is close to 100% if treatment is continued for 3 to 6 months. Cutaneous sporotrichosis has sometimes been treated with local heat therapy Footnote 3. Pulmonary sporotrichosis: Usually treated with amphotericin B or itraconazole however Footnote 3 it usually responds poorly to antifungal agents. Osteoarticular sporotrichosis: The response to treatment is slow. Itraconazole has become the drug of choice Footnote 3. Total knee arthroplasty may result in good functional outcome Footnote 10. Disseminated sporotrichosis: Initial treatment is usually initiated with amphotericin B and after initial improvement, is usually changed to itraconazole which may be continued lifelong for patients who have both HIV infection and sporotrichosis Footnote 3, Footnote 25. Other new oral antimycotic drugs such as triazole and saperconazole may be effective Footnote 1.
LABORATORY-ACQUIRED INFECTIONS: Several cases of sporotrichosis have described among laboratory workers who handled infected animals or cultures Footnote 3, Footnote 26, Footnote 27. The possibility of invasion of fungus through healthy and intact skin, and infection through accidental inoculation has been suggested as the main causes of infection Footnote 26-Footnote 28. Another possibility of transmission is attributed to the scratch or bite of cats or laboratory animals. Thus, the principal people at risk are veterinarians and their assistants Footnote 1.
SOURCES/SPECIMENS: Major environmental sources are contaminated soil, water and vegetation. Other sources include ulcerated lesions and infected animals (cats) Footnote 1, Footnote 14. Specimens are usually obtained by skin biopsy, and exudates or pus from cutaneous lesions Footnote 29. Also, sputum, synovial fluid, cerebrospinal fluid, and rarely, blood have been reported to yield fungus when cultured Footnote 3, Footnote 5, Footnote 11.
PRIMARY HAZARDS: Direct contact with broken skin and mucus membranes, needlestick and aerosol, handling of sphagnum moss, infected animals (bites and scratches) Footnote 2, Footnote 14, Footnote 28, cultures in the laboratory, and other research activities Footnote 26, Footnote 27.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 30.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 31.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 31.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
DATE UPDATED: September 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2011