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Leishmaniasis

leishmaniasis

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Leishmaniasis

  1. 1. Leishmaniasis shaibana
  2. 2. Introduction  Leishmania causes a fatal vector-borne parasitic disease called Leishmaniasis .  It is spread by the bite of sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World.  Leishmaniasis is the second-largest parasitic killer in the world (after malaria) and is endemic in many parts of Africa, Asia and South America.
  3. 3. Classification  Kingdom  Subkingdom  Phylum  Subphylum  Class  Order  Genus  Species  Protista  Sarcomastigophora  Protozoa  Mastigophora  zoomastigophora  Kinetoplastida  Leishmania  donovani, tropica, mexicana , braziliensis, etc.
  4. 4.  Can be classified based on 1. Clinical disease 1. Visceral 2. Cutaneous 3. mucocutaneous 2. Geographical distribution 1. Old world leishmaniasis 2. New world leishmaniasis
  5. 5. Visceral leishmaniasis  Aka., kala azar, most severe form of leishmaniasis  Caused by old world sps, L.donovani and L.infantum and new world sps, L.chagasi
  6. 6. L.donovani Habitat-  Are essentially the parasites of visceral organs.  Promastigote forms found in sand fly and in culture.  Amastigote forms found in man in reticuloendothelial cells of spleen, bone marrow, liver, intestinal mucosa, mesentric lymph node.
  7. 7. Geographical distribution  It is estimated that visceral leishmaniasis (VL) affects > 100 million people worldwide.  Over 90% of reported cases are from India, Bangladesh, Nepal, Sudan and Brazil. In India it is prevalent in the eastern region including Bihar, West Bengal, eastern Uttar Pradesh, Assam and foothills of Sikkim.  During the epidemic of 1984–1994 death toll was as high as 70% in the Sudanese population.  Due to emergence of drug resistance the prevalence is not subsiding, and in fact has spread to central Europe. For example, during the late 1990s hundreds of cases were reported in Switzerland.
  8. 8. Morphology  The parasite exists in 2 forms  1. Amastigotes – aflagellar stage  2. Promastigotes – flagellar stage
  9. 9. Morphological difference Amastigotes Promastigotes Aflagellar stage Flagellar stage Occurs in the vertebrate host Occurs in the sand fly divides by binary fission at 37oC divides by binary fission at 27oC. There are round or oval ;2-4µm along longitudinal axis. They are spindle shaped ;15-20 µm in length & 1- 2µm in width. Nucleus relatively larger and situated centrally Nucleus smaller and situated in the middle of the cell or along the side of cell-wall Kinetoplast situated right angle to nucleus Kinetoplast lies transversely near the anterior end.
  10. 10. Life cycle
  11. 11.  Life cycle completes in 2 different host  Sandfly – intermediate host  Humans and other vertebrates - definitive host  Source of infection:- infected sand fly  Mode of transmission:-  Bite of vector sandfly “Phlebotomus argentipus “  Blood transfusion  Congenital infection  Accidental inoculation in lab workers  Sexual intercourse  Infective form:- promastigotes
  12. 12.  Leishmaniasis is transmitted by the bite of infected female phlebotomine sand flies.  The sand flies inject the infective stage (i.e., promastigotes) from their proboscis during blood meals .  Promastigotes that reach the puncture wound are phagocytized by macrophages and other types of mononuclear phagocytic cells.  Promastigotes transform in these cells into the tissue stage of the parasite (i.e., amastigotes) , which multiply by simple division and proceed to infect other mononuclear phagocytic cells .
  13. 13.  Sand flies become infected by ingesting infected cells during blood meals .  In sand flies, amastigotes transform into promastigotes, develop in the gut (in the hindgut for leishmanial organisms in the Viannia subgenus; in the midgut for organisms in the Leishmania subgenus), and migrate to the proboscis .
  14. 14. Pathogenesis  After inoculation by sandflies, the flagellate(promastigote) form binds to macrophages in skin.  2 of the parasite surface molecules (63-kDa glycoprotein gp63 and lipophosphoglycan- LPG) bind with complement receptors(C3b and C3bi) present on surface of macrophages.  Promastigotes phagocytosed by macrophages are transformed into amastigotes and multiply by binary fission within phagolysosome of macrophages
  15. 15.  Amastigotes invade throughout the RES of spleen, liver, bone marrow, and LNs leading to progressive heterotrophy  Proliferation and destruction of RES of internal organs and heavy parasitisation of skin and other organs by parasitized cells are the characteristic pathological changes.
  16. 16. Clinical manifestations Incubation period: 3-6 months Onset: gradual or sudden 1. Pyrexia 2. hepatosplenomegaly 3. Lymphadenopathy 4. Anemia :- increased hemolysis, haemorrhage, replacement of BM. 5. Hypergammaglobulinaemia
  17. 17.  6. Others:- kala-azar with HIV co-infection Post 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.
  18. 18. Lab diagnosis Direct evidence Peripheral blood by thick film Blood culture in NNN medium Biopsy:- bone marrow or spleen Indirect evidence Blood count Serum tests Other methods Animal inoculation Leishmanin or Montenegro test Adlers test Laboratory diagnosis
  19. 19. Direct evidences…  Peripheral blood by thick film method.(Amastigote form)
  20. 20.  Microscopy of splenic smear  Most sensitive method to detect LD bodies  98% positivity average Amastigote density Grade >100 Parasites/field 6+ 10-100 Parasites/field 5+ 1-10 Parasites/field 4+ 1-10 Parasites/10 fields 3+ 1-10 Parasites/100 fields 2+ 1-10 Parasites/1000 fields 1+ 0 Parasites/1000 fields 0
  21. 21.  Microscopy of bone marrow aspiration  Samples collected from sternum or iliac crest.  LD bodies seen in stained smear  Safer than splenic puncture  54-86% positivity
  22. 22.  Culture media for axenic culture Biphasic media Novy & McNeal and Nicolle (NNN) medium Rabbit blood agar that has overlay of Locke’s solution and antibiotics the specimen are inoculated into water of condensation and observed for motile promastigotes for 1-4 weeks at 22˚C
  23. 23. Liquid media  Include cell culture medias such as  Schneiders  Grace’s  Mituhasi-Maramorosch Defined media  Dulbecco’s minimum essential media supplemented with Tween 80,haemin, biotin, bovine serum albumin fraction V
  24. 24. Animal inoculation  IP inoculation of chineese and golden hamster.  Amastigotes can be seen in stained impression smears of the spleen
  25. 25. Indirect evidences Blood count 1. Leucopenia (progressive) 2. Anaemia (raised ESR) Serum tests 1. Aldehyde test( napiers)- positive after 3 months. 2. Antimony test(chopras)- less reliable. Not used now. 3. Complement fixation test with W.K.K. antigen. Not used now. 4. Demonstration of antibodies (ELISA, DAT, IHA, IFA with specific antigen etc.) 5. Molecular diagnosis:- DNA Probes, PCR, etc.
  26. 26.  Leishmanin or Montenegro Test It is a delayed hypersensitivity test. 0.2 ml of leishmania antigen is injected intradermally. The test is read after 48-72 hrs. Positive result is indicated by an induration of 5mm or more. Positive reaction indicates prior exposure to leishmanial parasites. In kala-azar (visceral leishmaniasis), this test is negative.
  27. 27.  Aldehyde test of Napier  Add a drop of 40% formaldehyde to 1 or 2 ml of serum in a test tube.  Positive :- jellification of milky white opacity like egg white within 2-20 min.  Aldehyde positive Ab’s appear only after 3 months of infection  Antimony test of chopra  Development of white flocculent precipitate on addition of urea stilbamine solution to patients serum
  28. 28. Epidemiology  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.
  29. 29. Prevention and control Reduction of sand fly population Reduction of reservoirs Education in the community Prevention of exposure
  30. 30. Treatment drugs Sodium stibogluconate solution Amphotericin B Pentamidine Miltefosine Interferon
  31. 31. Cutaneous leishmaniasis  Aka., ‘Delhi boil’, ‘Aleppo boil’ or Leishmaniasis tropica  Caused by around 21 different spp.
  32. 32. Leishmania tropica complex  Includes Leishmania tropica:- Oriental sore Leishmania major:- rural cutaneous leishmaniasis Leishmania aethiopica:- cutaneous leishmaniasis of Ethiopia
  33. 33. Habitat  Parasites of Human skin  Amastigotes found in monocytes, polymorphonuclear leucocytes and endothelial cells of capillaries of skin  Not found in peripheral blood or internal organs Morphology  Similar to L.donovani Lifecycle  Similar to L.donovani except that amastigotes reside in large mononuclear cells of skin  Transmitted by P.argentipes
  34. 34. Pathogenesis  After inoculation by sandflies, the flagellate(promastigote) form binds to macrophages in skin.  Promastigotes are phagocytosed and transformed into amastigotes.  Papules develop at the site of bite, weeks or sometimes years after.  It is caused by multiplication of phagocytes that contain numerous amastigotes.  Lesion enlarges, necrosis, and ulcerates.
  35. 35.  Clinical manifestations i. Localised cutaneous leishmaniasis  Caused by L.tropica and L.aethiopica  Commonly seen in children and young adults ii. Oriental sore  Typical ulcer found on skin  Incubation period: 2 to 4 months  Lesion begins as single red, and pruritic papule at the site of bite. Gradually increase in size and finally ulcerates (Oriental sore).
  36. 36. iii. Diffuse cutaneous leishmaniasis  Caused by L.tropica occurs in an anergic host with poor immune response.  Patients develop multiple, wide spreaded papules and nodules iv. Leishmaniasis recidivans  Uncommon clinical form of leishmaniasis caused by L.tropica  Recurrence of leisions at the site of apparently healed disease years after a localized cutaneous lesion has healed.  Manifest as enlarging papules, plaque, or coalescence of papules that heals as central scaring at face  Destruction of nose
  37. 37. Epidemiology  1-1.5 new cases per year Geographical distribution  World :- Iran, Afganistan, Brazil, Peru, Saudi Arabia, and Syria.  India :- Rajasthan, Kerala, and Uttarakhand.
  38. 38. Laboratory diagnosis  Specimen : obtained from margin of ulcer by puncture of the raised nodules or aspiration of outer edge of the ulcer.  Microscopy  Geimsa or Leishman:- demonstration of amastigotes.  Culture  NNN medium  Animal inoculation  Intradermally in hamster  Serodiagnosis  Aldehyde test is negative  Leishmanin skin test :- positive
  39. 39. Leishmania Mexicana complex  Includes  Leishmania Mexicana Mexicana  Leishmania Mexicana amazonensis,  Leishmania Mexicana venezuelensis  Leishmania Mexicana pifanoi  New world cutaneous leishmaniasis  Chiclero ulcer aka bay ulcer
  40. 40. Mucocutaneous leishmaniasis  Most dangerous form of cutaneous leishmaniasis  Caused by L.vianna branziliensis
  41. 41. Leishmania vianna braziliensis  Widespread in latin America Habitat  Amastigotes are found in humans and other vertebrates.  Intracellular parasites and are found inside the macrophages of the skin and in the mucous membrane  Promastigotes are found in sandfly and culture
  42. 42. Morphology  Similar Lifecycle  Identical of L.donovani  Except that the amastigotes are found in reticuloendothelial cells and lymphatic tissues of skin Pathogenesis  Condition occurs when cutaneous lesions expand directly to mucosal region or through metastasis.  Pathogenesis of espundia and oriental sore is similar, except that  Espundia expand rapidly, forming large and long lasting ulcers with weeping surface  Mucosal metastasis
  43. 43. Clinical manifestations  More variable, chronic, and severe  Espundia  inital symptoms are similar to that of cutanous leishmaniasis  single or multpile lesions and ulcers develop at the mucosal regions (nose, mouth, throat cavities) and in the adjacent tissue  The ulcerations can involve the nose, pharynx, palate and lips. Invasion of the larynx may result in a loss of speech.  Pian bios:- single or multiple and painless dry persistent ulcers all over the body  Uta :- single or multiple ulcers in the face
  44. 44.  Geographical distribution  World : brazil, Paraguay, Ecuador, Bolivia, Peru, Colombia and Venezuela.  India : no condition  Vector  Lutzomiya spp.  Reservoir  Rodents.  Mode of transmission  Bite of sandfly vectors  Less frequently by ticks, direct human-human transmission and autoinfection
  45. 45. Laboratory diagnosis  Specimen :- slit skin biopsy, aspiration from edge of ulcer and from nodules in skin  Microscopy :- amastigotes in stained smear  Culture :- grows poorly  Animal inoculation :- slowly grows in Hamster and takes longer time to produce pathological lesions  Serodiagnosis :-  IFA  Leishmanin test :- positive
  46. 46. Thankyou

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