NAME: Leishmania spp.
SYNONYM OR CROSS REFERENCE: Leishmaniasis, kala-azar, Dum-Dum fever, black fever. The causative agents are members of the L. donovani complex, L. tropica, L. major, L. aethiopica, L. Mexicana complex, and Braziliensis complexFootnote 1,Footnote 2.
CHARACTERISTICS: Leishmania spp. belong to the family Trypanosomatidae, order KinetoplastidaFootnote 1. Leishmania spp. are characterized by a flagellated promastigote stage in a sandfly, and a non-motile amastigote stage within macrophages in mammalsFootnote 3,Footnote 4. The amastigotes, known as Leishman-Donovan (LD) bodies, are small, round or oval, and measures 3 to 5 µmFootnote 5. Eastern hemisphere: L. tropica, L. major, L. aethiopica. Western hemisphere: L. braziliensis and L. mexicana complexes.
PATHOGENICITY/TOXICITY: The clinical presentation of leishmaniasis is dependent on immune status, nutritional status, species, and strain. A spectrum of findings is observed within each of the three major clinical syndromes: cutaneous, mucocutaneous and visceral leishmaniasis. Cutaneous leishmaniasis (CL), due to L. tropica, L. mexicana, L. braziliensis or L. major, is characterized by ulcerative skin lesions. The morphology of the cutaneous lesions may vary depending of the Leishmania species. The symptoms can be pruritic, painful, and scarring is possible. Cutaneous leishmaniasis may include local/diffuse skin lesions, ulceration, adenopathy, satellite lesions, and subcutaneous nodulesFootnote 4,Footnote 6. Systemic symptoms are often absent. Mucocutaneous leishmaniasis (ML) caused by L. braziliensis and occasionally with other Leishmania spp, occurs years after the onset of cutaneous leishmaniasis. ML is characterized by one or several cutaneous lesions, and secondary infection is a risk, and progressive tissue destruction. Symptoms can include mucosal lesions, nasal obstruction/bleeding, deformation of palates, gingival oedema, and periodontitisFootnote 4. Nasopharyngeal lesions can be fatal due to secondary infection or respiratory complications. Visceral leishmaniasis, usually caused by the parasites of the L. donovani complex, is fatal if left untreated. Symptoms include fever with two daily peaks, hepatosplenomegaly with pancytopenia, wasting and weakness, darkening skin and anemiaFootnote 4. Post-kala-azar dermal leishmaniasis (also caused by L. donovani) follows 6 months to 5 years after an attack and/or complete cure of VL, causing hypopigmented macules, nodules and plaques, and erythema of the faceFootnote 7.
EPIDEMIOLOGY: Worldwide distribution. It is endemic in 88 countries, mostly developing countries, including parts of Europe, South America, Africa and AsiaFootnote 1. It is estimated that 12 million are infected worldwide, with 2 million new cases occurring every year, 1.5 million for cutaneous leishmaniasis and 500,000 for visceral leishmaniasisFootnote 4,Footnote 8,Footnote 9. Ninety percent of visceral leishmaniasis cases occur in Bangladesh, Brazil, India, Nepal, and Sudan; ninety percent of cutaneous leishmaniasis cases occur in Afghanistan, Algeria, Brazil, Iran, Peru, Saudi Arabia, and SyriaFootnote 4,Footnote 8.
HOST RANGE : Humans, warm-blooded mammals including dogs, cats, and small rodentsFootnote 2.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Transmitted by the bite of an infected female sandfly of the genus Phlebotemus or Lutzomyia Footnote 10,Footnote 11. The sand fly acquires the parasite from a zoonotic reservoir. Laboratory, blood transfusion, congenital and sexual transmission are possible, and transmission by domestic or wild mammals has also been reportedFootnote 1,Footnote 12.
INCUBATION PERIOD: At least a week but can be up to many months.
COMMUNICABILITY: Communicable via sandflies as long as parasites are circulating in blood or are present in skin lesions, although person to person infection through blood transfusion, sexual contact or placenta (mother to child) is rareFootnote 1. Parasites may still circulate in the blood after symptoms are no longer apparent.
ZOONOSIS: Yes, by bite of sandfly that has fed off an infected mammalian hostFootnote 1.
DRUG SUSCEPTIBILITY: Susceptibility has been observed for systemic agents such as antimony-based drugs, amphotericin, paromomycin, and oral miltefosineFootnote 8. Pentamidine is not preferred but has shown efficacy against relapse patients. A new agent, sitamaquine, has shown a 50% cure rateFootnote 8. Combination treatments may be used against pathogens with developed drug resistance. When administering parenteral treatment such as sodium-stibogluconate, factors such as risk for mucosal leishmaniasis development, and number, size, or complication of lesions of ulceration should be consideredFootnote 16.
DRUG RESISTANCE: Resistance against sodium antimony gluconate has been documented for all speciesFootnote 4.
PHYSICAL INACTIVATION: Leishmania spp. do not survive autoclaving condition of 121°C for 15 minutesFootnote 17. Their 100% lethal temperature is much lower than this (50°C).
SURVIVAL OUTSIDE HOST: Does not survive outside host or culture, but remains viable for 35 days in whole blood kept at 4 °CFootnote 19.
SURVEILLANCE: Monitor for symptoms. Diagnosis is made through microscopic identification of amastigotes in stained specimens from lesions. Identify parasite with real-time PCR of biopsy specimens from lesion fluid, western blot, rk39 immunochromatographic test, serological tests such as immunofluorescence assay (IIFA) and ELISA, and direct agglutination testFootnote 4. Species can be distinguished by targeting repetitive and polymorphic sequences by restriction enzymesFootnote 20.
FIRST AID/TREATMENT: Administer appropriate drug therapy.
LABORATORY-ACQUIRED INFECTIONS: Twelve reported laboratory acquired infectionsFootnote 21.
SOURCE/SPECIMENS: Infective stages may be present in blood, faeces, lesion exudates, and infected arthropodsFootnote 21.
PRIMARY HAZARDS: Accidental parenteral exposures, aerosols, vector-borne transmission, mucosal (mouth, nose, eyes), ingestionFootnote 21.
SPECIAL HAZARDS: Contact with lesion material, faeces, or blood, or receiving a bite from experimentally or naturally infected mammalsFootnote 21.
RISK GROUP CLASSIFICATION: Risk Group 2Footnote 22.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures. (Please note that containment requirements may differ depending on volume, production method, concentration, or additional factors which may alter the risk of potential infection, exposure, and/or environmental release).
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 splashesFootnote 23.
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 activitiesFootnote 23.
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 upFootnote 23.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposingFootnote 23.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelledFootnote 23.
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.
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