LeishmaniaPresented by:Mahesh YadavM.Sc. IIYr.Central Department of Microbiology,T.U
INTRODUCTION• Leishmania is a genus of trypanosomatidprotozoa, which causes a fatal vector-borne parasiticdisease called Leishmaniasis .• It is spread by the bite of sandflies of the genusPhlebotomus in the Old World, and of the genusLutzomyia in the New World.• Leishmaniasis is the second-largest parasitic killer inthe world (after malaria) and is endemic in manyparts of Africa, Asia and South America.
HISTORY• The parasite was named by RonaldRoss in 1903 after the Scottishpathologist William Boog Leishman.• In 1901, Leishman identified theorganism in smears taken from thespleen of a patient who had diedfrom "dum-dum fever“.
IMPORTANT SPECIES• L. donovani• L. tropica• L. mexicana• L. braziliensis• L.major• L.guyanensis• L.lainsoni• L.naiffi• L.aethiopica, etc
HABITAT(L.donovani) Are essentially the parasites of visceral organs. Promastigote forms found in sand fly and in culture. Amastigote forms found in man inreticuloendothelial cells ofspleen,bone marrow,liver,intestinal mucosa,mesentric lymph node.
L.donovani L. tropica L.mexicana L. braziliensisParasites of VisceralorgansSkin Skin Skin and mucusmembrane ofnose andbuccal cavityAmastigoteform found inHumanReticuloendothelialcells of•spleen,• bone marrow ,• liver•intestinalmucosaHuman•Reticuloendothelialcells of skinHuman•Reticuloendothelialcells of skinHuman•Macrophage of skin•Mucous membraneof nose and buccalcavityPromastigoteform found inSand fly andcultureSand fly andcultureSand fly andcultureSand fly andcultureHABITAT OF OTHER SPECIES
MORPHOLOGY(same in all species)• The parasite exists in2 forms;-1. Amastigotes –aflagellar stage2. Promastigotes-flagellar stage
Morphological DifferencesAmastigotes• Aflagellar stage• Occurs in the vertebrate host• divides by binary fission at 37oC.• There are round or oval ;2-4µm along longitudinalaxis.• Nucleus relatively larger and situated centrally.• Kinetoplast situated right angle to nucleus.Promastigotes• Flagellar stage• Occurs in the sand fly• divides by binary fission at 27oC.• They are spindle shaped ;15-20 µm in length & 1-2µm in width.• Nucleus smaller and situated in the middle ofthe cell or along the side of cell-wall.• Kinetoplast lies transversely near the anteriorend.
Life cycle of other species of Leishmania are similar toL.donovani except thatIn L.tropica• amastigotes reside in the large mononuclear cellsof the skinIn L.mexicana• Amastigotes found in reticuloendothelial cellsand lymphatic tissues of skinIn L.braziliensis• amastigotes are found in reticuloendothelial cellsand lymphatic tissues of skin and mucusmembrane
MODE OFTRAMSMISSION(L.donovani)1. Mainly by the bite of sand fly (vector) Phlebotomusargentipus2. Les frequently by• blood transfusion,• congenital infection,• accidental inoculation of cultured promastigotes in the lab.workers, and• sexual intercourse. Males are affected more (due to increased exposure to sandflies through the occupation and leisure activities).
RESERVOIR(L.donovani)• Human:- in Indian subcontinent• Rodents:- in Africa• Foxes:- in Brazil and Central Asia• Dogs :- In Mediterranean and China
L.donovani L.tropica L.mexicana L.braziliensisReservoir Man, rodents,foxes, dogsMan,DogSloth, anteater, rat, dogSloth, anteater, rat, dogVector Sand flyPhlebotomusargentipusSand flyPhlebotomusargentipusSand flyLutzomyia spp.,Sand flyLutzomyia spp.,Mode oftransmission•Bite of sandfly•blood transfusion•Congenitalinfection•sexual intercourseBite of sand fly •Bite of sandfly,•Bite of ticks ,•autoinfection•Bite of sandfly,•Bite of ticks ,•autoinfectionIndividual atriskMales areaffected moreAdolescents andyoung adultsPersons workingat the edge offorest and in thepeople staying inrural areas.Persons workingat the edge offorest and in thepeople staying inrural areas.Reservoir, vector and transmission of other species
CLINICAL MANIFESTATIONS1. Pyrexia2. Spleen enlargement3. Lymphadenopathy4. Darkening of the skin (KALA AZAR, MEANING “BLACK FEVER” IN HINDI, BECAUSE OF ITSTENDENCY TO DISCOLOR ITS VICTIM’S COMPLEXION DURING ADVANCED STAGES)5. Others:- kala-azar with HIV co-infectionPost kala-azar dermal leishmaniasis(PKDL) Complications:- pneumonia, TB, dysentery, uncontrolled haemorrhage Prognosis:- With an early treatment, cure rate >90%If not treated, death occurs within 2 years.
CLINICAL MANIFESTATIONS OTHER SPECIESL.tropica• Oriental sore• Acute necrotizing lesion• scarL.mexicana• Chiclero ulcer• Indolent nodular lesionL.braziliensis• Espundia• Uta• Pian bois
TYPES OFLEISHMANIASISLeishmaniasis is divided into clinical syndromesaccording to what part of the body is affected most.Visceral Leishmaniasis(VL)Cutaneous Leishmaniasis(CL)Mucocutaneous leishmaniasis(MCL)
Continued....1. Visceral Leishmaniasis (VL)or Kala-azar caused by L.donovani part of the body affected most isinternal organsSpleenomegaly
Continued....2. CutaneousLeishmaniasis(CL)( most common type)a) Old world CL:- caused byL.tropica, L. aethiopicab) New world CL:- caused byL.mexicana, L.braziliensis, L.guyanensisc) Dermal leishmanoid or Postkala-azar dermalleishmaniasis(PKDL):- causedby L.donovani Part of the body most affectedis skin
....continued3. Mucocutaneousleishmaniasis(MCL) Caused by L. braziliensisand occasionally byL.panamensis Part of the body affectedmost is skin and mucousmembrane of nose andpharynx
LABORATORY DIAGNOSISDirect EvidencesPeripheral blood by thickfilmmethod.(Amastigoteform)Blood culture in N.N.N.Medium. (Promastigoteform)Biopsy material obtained bylymph nodepuncture, sternal or iliaccrest puncture(marrow)and spleen puncture(spleenpulp) only for L. donovaniIndirectevidencesBlood countSerum TestsOthermethodsAnimalinoculationLeishmanin orMontenegroTestAdler’s test
Direct Evidences (contd......)1. Peripheral blood by thickfilm method.(Amastigoteform)Amastigotes in a macrophage
Direct Evidences (contd......)2. Blood culture in N.N.N.Medium. (Promastigoteform)Promastigote from culture in NNN medium
Direct Evidences (....contd)3. Biopsy material obtainedby• lymph node puncture,• sternal or iliac crestpuncture(marrow) and• spleen puncture(spleenpulp)Amastigote form in a stained smearPromastigote in culture in NNN mediumAmastigotes of L. donovani.Splenic aspirate.
Indirect evidences1. Blood count:-• Leucopenia (progressive)• Anaemia (raised ESR)2. Serum Tests• Aldehyde test- positive after 3months.• Antimony test- less reliable. Notused now.• Complement fixation test withW.K.K. antigen. Not used now.• Demonstration of antibodies(ELISA, DAT, IHA, IFA with specificantigen etc.)• Molecular diagnosis:- DNAProbes, PCR, etc.
Other methods• Animal inoculation Wherever in vitro facilitiesare not there, the material from patients can be injectedintraperitoneally in hamster or mice and the parasite is recoveredfrom the animal. In positive cases, the amastigotes can bedemonstrated in the stained impression smears of spleen fromanimals.• Leishmaninor Montenegro TestIt is a delayed hypersensitivity test. 0.2 ml of leishmania antigenis injected intradermally. The test is read after 48-72 hrs. Positiveresult is indicated by an induration of 5mm or more. In kala-azar(visceral leishmaniasis), this test is negative• Adler’s test:- It is a serological method. Thedevelopment of promastigote forms of Leishmania in Locke’s serumagar can be inhibited by a immune serum specific toL.donovani, L.tropica and L.braziliensis.
EPIDEMIOLOGY• Found in more than 88 countries.• Found on every continent except Australia and Antarctica.• For cutaneous leishmaniasis, number of cases range from 0.7 million to 1.2 million .• For visceral leishmaniasis, number of cases range from 0.2 million to 0.4 million.• Annual incidence of disease= 600,000 cases per year.• People infected worldwide=12 million.• People at risk=350 million.
GEOGRAPHICAL DISTRIBUTIONS• Present worldwide.• Most of the affected countries are in the tropics and subtropics.• More than 90 percent of the worlds cases of visceral leishmaniasis are inIndia, Bangladesh, Nepal, Sudan, and Brazil.Leishmaniasis is found in• Asia (not Southeast Asia),• Central America,• South America (not in Uruguay, Chile, or Canada),• Southern Europe (not common in travelers to southern Europe),• The Middle East, and• Africa (particularly East and North Africa, )
Current Geographic Distribution ofLeishmaniasis (....contd)
Leishmaniasis in Nepal• Visceral leishmaniasis (kala azar) is common in the Terai region.• The first confirmed case of VL was recorded in 1980.• A total of 25890 cases with 599 deaths were reported during 1980-2006.• During 2003, highest incidence (per 100,000) was in Mahottari district (184), followed bySarlahi (100) and Sunsari (96).• Highest case fatality rate (CFR) was in Dhanusha (2.9%) followed by Bara (2.4%) and Saptari(2.0%).• Cutaneous leishmaniasis is rare in Nepal.• First case of cutaneous leishmaniasis was reported in the year 2006 in Nepal.
Reduction of sandfly populationby insecticides mainly DDT,dieldrin, malathionReduction ofreservoirby killing all the infected dogs in thecases of zoonotic kala-azar.Education in thecommunityAbout the causes and modes oftransmission of leishmaniasis.Prevention ofexposure to sand flyusing insect repellent, bed nets and windowmess as needed.PREVENTION ANDCONTROLPREVENTION AND CONTROLThere are No Vaccines to prevent leishmaniasis.
TREATMENTDrugsSodiumstibogluconatesolutionInhibits glycolytic enzymes and fatty acidoxidationAmphotericinBBinds with ergosterol leading to the alteredpermeability to cations, water, glucose and affectmembrane-bound enzymes.Pentamidine Inhibits DHFR and interferes with aerobic glycolysisin protozoa, also inhibits protein synthesisMiltefosine Effects cell-signaling pathways and synthesis of thecell-membraneInterferonmacrophage activation
Specific therapysupplemented withtreatment of secondarymicrobial infectionshigh-calorie-high proteindietBlood transfusion insevere anaemiaTREATMENT (....contd)
REFERENCES• www.who.int• www.cdc.gov• www.Leishinfonet.com• Chatterjee KD,(2009), Parasitology protozoology andhelminthology, 13th edition, CBS publishers anddistributers pvt. Ltd. New Delhi, India Page no.64-89• Parija S.C., (2004), Textbook of Medical Parasitology, 2ndedition, All India publishers and Distributers. Page No.81-103