Leishmaniasis is an infectious protozoan disease of animals and man characterized by two forms – the visceral and cutaneous. Greek term ‘Ponos’ means pain. Ponos denotes ‘Kalaazar’.
Distribution
The disease is distributed in countries like Central and South America, Central Asia, China, Russia, Sudan, Ethiopia, Africa and India. The disease has been recorded in man and animals from some states of India.
Greece has the privilege to be one of the Mediterranean region where both man and animal suffered since 1835. In India in 1930 identification of the agent was done.
Avari and Machie (1924) found leishmanial ulcer on the ears of a dog in Bombay. Afterwards Faust and Russel (1957) recorded the same in dogs from Bombay. It was suggested by Omran (1961) and Lysenco (1971) that oriental sore is prevalent in the dry western half of Indo-Gangetic plains including Gujarat and Rajasthan. The disease has been recorded by various workers from time to time from in and around Bikaner, Rajasthan. Lodha (1971) and Mishra (1971) reported cutaneous Leishmaniasis in dog and man from Bikaner. Ahuja in 1993 and 2001 have studied about occurrence and clinical accounts on Leishmaniasis in Bikaner (Rajasthan).
Aetiology
The disease is caused by Leishmania donovani and L. tropica. The organism occurs as round or oval bodies measuring 2-3 micrometre in diameter. In the Mediterranean, the causative agent is Leishmania infantum.
Susceptible Hosts
It is primarily a disease of man and dog but has been recorded from some wild animals like wild cats, jackel, fox, wolves, porcupine and rodents.
Transmission
The disease is transmitted by various species of sandfly Phlebotomus spp. Dog has been considered to take part in transmitting human infection.
Clinical Findings
The incubation period ranges from 3 months to several years. Leishmania tropica causes cutaneous leishmaniasis where small focal lesions appear on the skin. This skin lesion thus formed is known as oriental sore. Leishmania donovani causes visceral leishmaniasis where generalised skin diseases are noted. This leishmania causes kala-azar or Dum Dum fever. Besides skin lesions, there is loss of body weight, poor appetite and lymphadenopathy.
There is also ocular lesions, signs of renal failure, epistaxis, lameness and anaemia. Some may show diarrhoea and hepatic insufficiency. In cutaneous form, there is formation of chronic ulceration particularly on head and limbs. The dogs with such disease has been grouped as:
Asymptomatic resistant dogs
Asymptomatic dogs (Pre-clinical)
Dogs with minimum signs (aliposymptomatic)
Symptomatic dogs
Diagnosis
- Demonstration of parasites in the smear of skin or ulcer scraping.
- Organisms can be demonstrated in lymph node and biopsy smears.
- Histopathology of visceral organs (specially spleen)
- FAT
- ELISA
- PCR
Treatment
- Antimonial preparations are used
- In case of human being, urea stibamine is used.
- Meglumine antimonate (Glucantine) can be used IM in dog.
- Allopurinol at the rate of 20 mg/kg/day orally
- Other drugs: Paromomycin (aminosidine), Azoles, Pentamidine or lomidine and Amphotericin B.
Control
- Detection of the clinical case.
- Segregation of the positive one.
- Control of vector and thereby breaking the life-cycle.
- Reduction of stray dog population.
