1. Leishmania donovani ___________________

2. Charles Louis Alphonse Laveran
                                
                     
France
Institute Pasteur Paris, France
The Nobel Prize in Physiology or Medicine 1907
"in recognition of his work on the role played by protozoa in causing diseases"

3. Leishmaniasis is prevalent world wide: ranging from south east Asia, Indo-Pakistan, Mediterranean, north and central Africa, and south and central America.

4. Species Pathogenic in Humans
Leishmania donovani (Laveran 1903) (VL)
Leishmania tropica (CL)
Leishmania major (CL)
Leishmania aethiopica (CL)
Leishmania mexicana (CL)
Leishmania brazilliensis (MCL)

5. Morphology Promastigote Amastigote Digenetic Life Cycle Insect Motile
Midgut
Amastigote
Mammalian stage
Non-motile
Intracellular

6. Morphology Amastigote (leishman-donovan body):
Human phase, reside in macrophage
Very, very minute elliptical body
No free flagellum
Nucleus: deep red, located at one side
Cytoplasm: blue (after right stain)
Kinetoplast; basal body; rhizoplast

7. elongate form - 15 - 30 µm long
Promastigote
elongate form
µm long
one nucleus, red stained, central in position,
one anterior flagellum which is just as long as its body length.
a rod-like kinetoplast
a dot-like basal body
anterior
Flagellum
Basal body
Kinetoplast
Nucleus
posterior
Insect
Motile
Midgut

8. Promastigote: Vector phase Reside in the gut of sandfly
Spindle shaped with 1 free flagellum
Nucleus; cytoplasm; kinetoplast; basal body; rhizoplast
Chrysanthemum-like in culture medium

9. A macrophage filled with Leishmania amastigotes.

10. Amastigote of L. donovani (under oil immersion objective)

11. Amastigote
M broken with the release of amastigote which may invade other M, start asexual multiplication again

12. Promastigote Fusiform -shaped with 1 free flagellum
Usually gather together in the medium as a mum

13. Promastigote

14. Electron photomicrograph of promastigotes

15. promastigote mum (under electron microscope)

16. Sandflies

17. Phlebotomus ，sandfly
Small，about 1/3 of a mosquito, 3mm, yellow-gray

18. Life cycle

19. Life Cycle of Leishmania spp.
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20. Promastigote Amasitgote
Life Cycle
Promastigote Amasitgote
Transformation

21. Main points of the Life Cycle
2-host pattern, mammal insect vector (sandfly)
Asexual multiplication occurred either in macrophages or in insect , No sexual development in the host
infective stage: promastigote
mode of infection:  biten by sandfly
site of habitation:  macrophages
pathogenic stage:  amastigotes
diagnostic stage:  amastigotes
reservoir host: dogs and rodents

22. Leishmania donovani PATHOLOGY:
Amastigotes multiply in macrophage, destroyed the macrophage
eventually rupturing the cell
Free amastigotes then invade the circulatory system.

23. Parasite Spread Macrophage lysis & parasite release Target organs
1. Lymphatic spread
2. Blood spread
Target organs
the mononuclear macrophagocyte system of the spleen, liver, bone marrow and lymph nodes

24. Clinical features
Lack of acquired immunity but may gain sterilizing immunity after effectively cured.
Most severe form of the disease, may be fatal if left untreated, Reason: lack of immunity after infection.
Irregular fever for long period is due to the broken piece from parasitized tissue.
Massive hypertrophy of spleen , liver and lymph nodes are caused by the proliferation of mononuclear macrophagocytosis system. Destruction, hyperfunction

25. Clinical features
Because bone marrow is involved and spleen is hyperfunction, caused anemia.
The number of red blood cells( RBCs), white blood cells (WBC) and platelet all decrease.
Bleeding results from the decrease in blood platelets.
The decrease of liver function and the proliferation of plasma cells bring about the ratio of albumin to globulin is inverted.
Skin lesions – granulomatous response: painless nodules in which amastigote may be found – sometimes self-cured
Nephrosis: IC deposition –type III hypersensitivity.
Emaciation with ascites, darkened skin, fever, bleeding of the gums, immunity decrease. Die of infective complications( noma, Pneumonia).

26. Clinical Disease Visceral Cutaneous Fatal (90% untreated)
Liver
Spleen
Bone marrow
Cutaneous
Generally Self- healing
Skin
Mucous membranes

27. Profile view of a teenage boy suffering from visceral leishmaniasis.
The boy exhibits splenomegaly, distended abdomen and severe muscle wasting. 

28. Two children with visceral leishmaniasis
Splenomegaly

29. Enlarged spleen and liver in an autopsy of an infant dying of visceral leishmaniasis.

30. Jaundiced hands of a visceral leishmaniasis patient. 

31. Special clinical features for Kala-azar cases
Post-kala-azar dermal leishmaniasis (PKDL)：

32. Cutaneous leishmaniasis of the face.

33. A cutaneous leishmaniasis lesion on the arm.

34. Cutaneous leishmaniasis

35. Diagnosis Etiological examination
Puncture smear: bone marrow – safe, first choice
Skin biopsy
Tissue or aspirate cultivation
Animal inoculation

36. Molecular biology methods
Immuno-diagnosis
Antibody detection
Circulation antigen detection
Molecular biology methods
DNA probe test
PCR

37. Treatment Injection of Antimony Gluconate cure rate would be 97.4％
Good nursing
Pentamidine or stilbamidine for antimony-resistant patients
Antibiotics
Spleen excision

38. Epidemic Links Source of infection: patients and dogs
Route of infection: sandfly.
Susceptible population:
all human beings ( but potent immunity developed after cure)

39. Prevention Treat the patients
Suppress the reservoir: dogs, rats, other small mammals and rodents
Suppress the vector: Sandfly
Prevent sandfly bites: Personal Protective Measures

40. Trichomonas vaginalis (阴道毛滴虫)
Trichomonas vaginalis, a flagellate, is the most common pathogenic protozoan in the countries. It causes trichomoniasis (毛滴虫病). The infection is transmitted sexually.

41. Morphology Pear-like in shape, about 10-30x5-15um in size.
four anterior flagella and One posterior flagellum which attaches to pellicle to form an undulating membrane (波动膜).
One nucleus
the axon project posteriorly out of the body.
The motility is jerky & non-directional.

42. Trichomonas vaginalis

43. Life cycle: Simple: Only Trophozoite stage. There is no cyst stage.
Binary fission of reproduction.

44. Inhabitation: Female – Vagina(阴道) , Urethra（尿道）;
Male – Urethra （尿道）, Prostate glands.
Cause
Trichomonas vaginitis, urethritis
or prostatitis, i.e. Trichomoniasis.

45. Diagnosis 1. Etiological examination
The specimen should be obtained from vaginal discharge, prostatic fluid or urine. Normal direct smear may be used for exam. the trophozoites. The typical robust Trichomonas can be seen because of their characteristic jerky motion moving among the epithelial cells.
2. PCR & DNA probe

46. Treatment Metronidazole is the drug of choice for both female & male.
Sexual partners should be treated at same time.

47. Epidemiology
Like most sexually transmitted diseases, trichomoniasis is prevalent in the sexually active age group in all climates and racial groups.
New born girls appear to be at special risk of acquiring trichomoniasis from an infected mother during passage through the birth canal.

48. Although the organism died rapidly when dried , exposed to direct sunlight, person to person transmission may occur where there is a lack of sanitary toilets or bathing facilities and a sharing of contaminated clothing or washcloth.

49. Control 1. Treat patients & Carriers.
2. Pay attention to personal hygiene.
3. Avoidance of sexual contact with infected partners .

50. opportunistic protozoa
opportunistic protozoa can not infect persons with normal immune mechanisms or can cause mild (or latent) infection with asymptomatic to self-limited symptoms .
opportunistic protozoa may cause devastating disease in persons whose immune resistance has been weakened by various causes, such as:

51. immune deficiencies: eg. AIDS
Malnutritions
Malignancy 恶性肿瘤
Immunosuppresive medications:
eg. organ transplantations
Homosexuals

52. Toxoplasma gondii (toxoplasmosis)

53. Introduction
Toxoplasma gondii has very low host specificity, and it will probably infect almost any mammal. It invades all kinds of cells except RBC
Cats are the only definitive hosts and can also be the intermediate hosts
The disease that Toxoplasma gondii caused (toxoplasmosis) has been found in virtually every country of the world
Toxoplasmosis is a significant cause of morbidity and mortality in AIDS patients and congenitally infected infants -- opportunistic infection for human

54. Toxoplasma is an obligate intracellular parasite
Toxoplasma is an obligate intracellular parasite.  Its life cycle includes two phases called the intestinal and extraintestinal phases. The intestinal phase occurs in cats only and produces "oocysts."  The extraintestinal phase occurs in all infected animals (including cats) and produces "tachyzoites" and, eventually, "bradyzoites" or "zoitocysts."  The disease toxoplasmosis can be transmitted by ingestion of oocysts (in cat feces) or bradyzoites (in raw or undercooked meat).

55. In most humans infected with Toxoplasma, the disease is asymptomatic
In most humans infected with Toxoplasma, the disease is asymptomatic.  However, under some conditions, toxoplasmosis can cause serious pathology, including hepatitis, pneumonia, blindness, and severe neurological disorders.  This is especially true in individuals whose immune systems are compromised (e.g. AIDS patients).  Toxoplasmosis can also be transmitted transplacentally resulting in a spontaneous abortion, a still born死产, or a child that is severely handicapped mentally and/or physically.

56. Morphology
There are five forms in T. gondii life cycle: trophozoite (tachyzoite, 速殖子), tissue cyst (bradyzoite, 缓殖子), schizont (裂殖体), gametocyte (配子体) and oocyst (卵囊).

57. Life Cycle

58. The tachyzoites directly destroy host cells
Pathogenesis
The tachyzoites directly destroy host cells

59. Clinical features
Acquired toxoplasmosis
Congenital toxoplamosis

60. Congenital Toxoplasmosis
(1) malformation of fetus (birth defect)
(2) abortion, premature delivery and stillbirth

61. Acquired Toxoplasmosis
the tachyzoites destroy tissues, causing extensive lesions in the lung, liver, heart, brain and eyes.
Symptoms:
fever, headache, muscle pain, swollen lymph glands

62. In immunocompromised individuals,
T. gondii infection results in generalized parasitemia involvement of brain, liver lung and other organs, and often death.

63. Diagnosis Microscopic Examination Animal Inoculation Serological tests
-Smears and Sections
Animal Inoculation
Serological tests
PCR & DNA probes

64. Epidemiology
This disease is widespread and clinically important throughout the world.
Human infections result from eating raw meat.
Lots of mammals can serve as reservoir hosts.

65. Reasons of epidemic Source of oocysts ...
domestic and wild cats, passes tons of oocysts
Persist in environment if moist
reservoir of infective oocysts
Many intermediate hosts with infective stage
reservoir of infective tissue cysts

66. Pneumocystis carinii Pneumocystis jiroveci (pronounced as "yee row vet zee")

67. Introduction
Pneumocystis jiroveci has a world-wide distribution and the transmission seems to occur by airborne route.
Pneumocystosis is one of the most common infections in immunosuppressed patients.

68. Morphology
Trophozoites and cysts are the two main stages in the life cycle
Life cycle
Not yet completely clear

69. Cryptosporidium spp.

70. Introduction
A threat to the quality
of surface water
and the environment...!
Cryptosporidium is a protozoan parasite in water environment
Causal agent of acute diarrheal disease in human and animals -- zoonosis
Potentially lethal for immunosuppressed individuals

71. Diagnosis Stool examiniation for oocysts
Biopsy of the intestine epithelium
！！Multiple stool samples (at least 3) should be tested before a negative diagnostic interpretation is reported