Sporotrichosis or Rose Handlers Disease

Sporotrichosis or rose handlers disease is a chronic, contagious and suppurative granulomatous disease caused by a fungus.

Sporotrichosis or rose handlers disease develops cutaneous nodules and ulcers over the skin and subcutaneous tissues along the lymphatic tracts.

Etiology

Sporotrichosis is caused by a fungal organism (Sporotrichum Schenckii, S. beurmanii, and S. equi). It is a dimorphic fungus, forms a single walled, cigar or round or oval shaped spores, which is 3-5 microns in length.

The fungus survives in decaying or decomposed organic plant materials, wood and soil. The fungus appears as mycelial form while living on decaying plant materials and assumes yeast form while it enters through punctured wound in the mammalian host.

Epidemiology

Prevalence of infection

This disease in animals is known since 20th century. Occurrence of the disease is sporadic. The first case of this disease was reported in human by Schenck in 1898 in US. It is also widely prevalent in many countries such as Europe, United States and India. Assam and West Bengal in India recorded with more prevalence in human and was first reported in 1932 followed by 1967, 1973 and 1979.

This fungus found in garden plants such as rose bushes moss varieties barberry bushes and mulches.

Economic Impacts

There is no heavy economic loss recorded because of the slow spreading nature of the disease, less mortality and the very good response of the organism to the treatment.

Source of infection

Contaminated soil, decaying plant materials, infected animals.

Transmission

Direct contact with infected animals spread the disease. Spreading of infection from affected cats to human has been recorded but not from infected horses to humans.

Host affected

Horses, cattle, cats, camels, rats, and chimpanzees are affected. Persons those working in the age.

Pathogenesis

The entry of the organism into the body occurs through inhalation, invasion and via open wounds. Invasion through wounds results in the development of abscesses and discharging ulcers. Multiple and small cutaneous nodules formed on the lower part of leg and fetlock region.

Suppurative inflammation at the initial period and well marked ulceration, necrosis at later stage of infection over superficial layer of the skin is identifiable.

Invasion of lymphatic tissue and regional lymphnodes of the proximal part of the leg produces lymphadenitis. Nodules are painless, discharge pus and forming scab and healing occurs in 3-4 weeks.

Debility and immuno-suppression produces systemic diseases. Sometimes, unhealed lesions persist in animal for months. Systemic spread of infection to lung, CNS, bones and joints occurs.

Clinical signs

Cutaneous form

This form is more common in dogs and cats. Multiple cutaneous nodules become ulcerate and drained the pus. Lesions located at the extremities and fetlock joint. Nodules are painless, discharging small amount of reddish colored exudate.

Lymphatic form

This form mostly seen in horses, donkeys and mules. Multiple nodules appear on lymphatic channels like nodular cords. Nodules are deeply ulcerated and delay the healing process. Dissemination in to visceral organs of horses rarely occurs.

Systemic form

Dissemination of infection to different parts of body including, lung, CNS, bones and other internal organs occurs.

Zoonosis

In human being, infection occurs through inhalation.

Necropsy Findings

Nodular, ulcerative and necrotic lesions seen. Initially, granuloma with purulent discharge, epitheloid granulomatous tissues with connective tissue capsule. Infiltration by macrophages, epitheloid, multinucleated giant cells and lymphocytes seen in later stages. Red oblong bodies can be seen in side the cytoplasm of the giant cells.

Diagnosis

• Based on clinical signs and necropsy findings.
• Isolation and identification of organism.
• Demonstration of spores in exudate and discharge.
• Identification of spores in air dried smears of exudate stained with Wright stain, or Romanowsky stain.
• Periodic acid Schiff stain to demonstrate the oval, round or cigar shaped spores.
• Experimental infection of rat, hamsters and mice with pus or cells via intra peritoneal route develops peritonitis and disseminated lesions in bones they may be containing yeast like cells.
•  Mycelia develops in agar culture appears as a fine septate hyphae visualized by microscopic examination.
•  Conidia are pyriform to spherical in shape on glass slides and the hyphae appears in floral like arrangements.
• Zinc and magnesium have inhibitory role in regulation of yeast to become mycelia where Ca ion has got stimulatory effect.
•  Fluorescent antibody test (FAT) is found to be simple, rapid and specific, where Precipitation tests is sensitive. Tube agglutination test is 55-71% effective and detecting visceral form of disease.

Sample Collection

• Exudate
• Wound swab
• Pus

Differential Diagnosis

• Epizootic Lymphangitis
• Glanders
• Ulcerative Lymphangitis
• Histoplasmosis

Treatment

• Administration of Sodium Iodide and Potassium Iodide is effective for the treatment of cutaneous, subcutaneous and systemic form of infection.
• Local application of tincture Iodine daily to ulcers may sufficient in treating the mild cases.
• Itraconazole is effective.
• Sodium Iodide 10.0g/40kg bw is given as 10% solution through intravenous route.
• Oral griseofulvin, Amphotericin B by I/V are highly effective in extra cutaneous form.
• Reactivation of healed lesion by steroid injection is possible.
• Treated with potassium iodide.
• Itraconazole (Sporonox) .

Prevention

Disinfection of infected articles, equipments and shed with antifungal agents will prevent the spread of infection in enzootic areas.

Control

Segregation of infected animals Cleaning of cut wounds, abrasions with tincture iodine. Washing of hands and arms with povidone iodine or chlorhexidine.