29. parasites

MICROORGANISM

1. PARASITES RATHEESH R.L

2. PARASITES A parasite is defined as an organism that lives in or on another organism and derives it nourishment without giving anything in return.

3. PARASITOLOGY Parasitology: it is the study of parasites and such does not include bacterial, fungal and viral. Medical parasitology deals with the parasites which cause disease in man and animals.

4. CLASSIFICATION Human parasites are mainly divided into Intestinal parasites For a parasite to be defined as intestinal it must have an intestinal life-cycle stage, though it may have life cycle stages in the heart, circulation, lung, tissue of other animals or environment.

5. Blood borne parasites: These are the parasites which are transmitted through an anthropod vector. The most important anthropod for transmitting parasitic infection is mosquito.

6. A parasite is defined as an organism that lives in or on another organism and derives it nourishment without giving anything in return.

7. The parasite may be, Ectoparasite : parasite living on the body surface of the host. Eg : lice Endoparasite : parasite living inside the body of the host. Eg : roundworms Obligate parasite: parasites which are completely depending the host. Eg : plasmodium Facultative parasite: parasite that may be capable of living independently, although they can obtain nourishment from the host too.

8. Periodic parasite: parasite which live part of their lives on a host and another part of life outside of the host. Accidental parasites: parasites which lives in an unnatural host. Aberrant parasites: parasites which can live on particular sites and when migrate to other sites it cant be survive. Intermittent parasites: parasites which visits the hosts at intervals. Specific parasites: parasites which complete the life cycle in specific host only

9. HOST A host is an organism on which the parasites lives. Types are, Definitive host: a host in which the parasites lives in the adult form. Intermediate host: a host in which the parasites lives in the larval form . Paratenic host: a host in which the parasites lives without undergoing any development

10. Accidental or casual host: a host in which the parasites lives by accident. Natural host: a host in which the parasites lives naturally. Reservoir host or carriers: host which makes the parasite available for transmission to other host. Transport host: it’s a kind of host in which no development of the immature parasite occurs. The parasite does not develop within the transport host, but can be transferred from one host to another.

11. HUMAN PATHOGEN PROTOZOON PARASITES RHIZOPODA Entamoeba histolytica MASTIGOPHORA Intestinal flagellates Giardia intestinalis Trichomonous hominis Genital flagellates Trichomonous vaginalis Haemo flagellates Trypanosoma gambiense Leishmania donovani

12. Sporozoa Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium uvale Ciliata Balantidum coli

13. RHIZOPODA

14. Entamoeba histolytica HABITAT: The organism lives in the mucous and sub mucous layer of the large intestine.

15. LIFE CYCLE Infection by Entamoeba histolytica occurs by ingestion of mature cysts in the fecally contaminated water , food or hands. These cytes are reached to the bowel of the human through consumption and passed with stools. When reaching the stomach the 4 nuclei in the stomach will come out .each of the nuclei is surrounds itself by a bit of protoplasm and forms amoebula , which grows and is known as trophozoite .

16. These trophozoits are actively motile and move towards the ileosacral region and affecting the wall of intestine. Then these are passed out through feces and the life cycle is repeated.

17. CLINICAL FEATURES It causes gastro intestinal infection known as amoebiasis . The symptoms are, Dysentry Bloody diarrhea Mucous in stool Weight loss Fatigue Abdominal pain When the infection spreaded through the blood means it can cause infection to the lungs, brain, spleen and the liver

18. LAB DIAGNOSIS Macroscopic examination: Dark red stool mixed with blood and mucous Microscopic examination of the stool: Used to demonstrate trophozoites or cysts of the organism Culture: Fresh specimen can be cultured in locks egg albumin medium, craigs medium and balamuths medium Serological tests: ELISA, LAT and indirect haemagglutination test

19. TREATMENT Iodoquinol , paromomycin or diloxanide furoate are the drug used incase of asymptomatic infections. Metranidazole is the drug used in symptomatic infections

20. TRANSMISSION Through human excreta Food handling by the infected individuals Through cockroach and house flies

21. PREVENTION Wash hands with soap and water Good sanitary practice Avoid sharing of the personal belonings Drink the boiled water only.

22. MASTIGOPHORA

23. Intestinal flagellates Giardia intestinalis Trichomonous hominis Genital flagellates Trichomonous vaginalis Haemo flagellates Trypanosoma gambiense Leishmania donovani

24. Giardia intestinalis Otherwise known as giardia lamblia or lamblia intestinalis . HABITAT: Lives in the duodenum and upper parts of the small intestine.

25. LIFE CYCLE The infection occurs by the ingestion of the cysts in the contaminated food, water or fecal oral route. These cysts can survive in the cold water for several months. After reaching to the small intestine it release trophozoites and these trophozoites will attach to the villi of the small intestine and multiplication occurs.

26. CLINICAL FEATURES The infection is commonly known as giardiasis Acute giardiasis develops after an incubation period of 1-14 days. Symptoms are diarrhea, abdominal pain, bloating, nausea and vomiting, malabsorption etc

27. DIAGNOSIS Microscopy: done to demonstrate the cysts in the stool and duodenal contents. Serological tests: ELISA, indirect immunoflurescene , counter current immuno electrophoresis, EIA.

28. TREATMENT Drugs for treatment are, Metronidazole Tinidazole Furazolidone

29. TRANSMISSION Through contaminated water and food Unclean hands

30. PREVENTION Drink the boiled water Check the food and vegetables for any types of fecal contents.

31. TRICHOMONOUS VAGINALIS HABITAT: vagina of the females and urethra in males.

32. LIFE CYCLE The parasite lives in the lower genital tract in the females and males it lives in the urethra and prostate. The total growth and the multiplication is taking place in these sites. They does not appear in the form of cysts and does not survive in the external environment. The transmission is mainly occuring during sexual intercourse.

33. CLINICAL FEATURES The infection is commonly known as trichomoniases Symptoms in females are, Vaginitis with purulant discharge Abdominal pain Dysuria Greenish or yellow secretions from the vagina Symptoms in males are, Urethritis Epididymitis prostatitis

34. DIAGNOSIS MICROSCOPY: Its helps to identify the actively motile organisms in the specimen. CULTURE: The most commonly used media a re cysteine peptone liver maltose SEROLOGICAL TESTS: Indirect haemagglutination test

35. TREATMENT Metranidazole and tinidazole therapy is usually succesful .

36. TRANSMISSION Unprotected sexual contact

37. PREVENTION SAFE SEX

38. LEISHMANIA The parasite coming under the group is leishmania donovani . HABITAT: natural habitat is reticuloendothelial system especially liver ,spleen, bone marrow , intestinal mucosa.it may be also find in endothelial cells of kidney, lungs , CSF and meninges.

39. LIFE CYCLE Leishmania is transmitted by by the bite of female sand fly, phlebotomous ( a small fly which bites at night ). The organism exist in two forms amastigote form also called aflagellar form(non motile form) and mastigote form also called flagellar or leptomonad form.

40. T he sand fly sucks the promastigote (motile) form of organism along with the blood of the patient during blood meals. The promasigote form after multiplication in the body of sand fly ascend to pharynx and reaches its buccal cavity . Eventually the buccal cavity of sand fly is blocked by these promastigote form and are to be released from mouth before taking second meal.

41. D uring biting these promastigote form enters the circulation and the cycle continues.

42. CLINICAL PICTURE There are 3 main clinical forms of leishmaniasis caused by different species of leishmania . CUTANEOUS LEISHMANIASIS MUCOCUTANEOUS LEISHMANIASIS VISCERAL LEISHMANIA (KALA AZAR)

43. CUTANEOUS LEISHMANIASIS it is most common form relatively benign, self healing skin lesions. T hese lesions are found in areas where sand flies bite. One or more sores occur in skin which changes in size and appearance. The infecting species are L.tropica , L.major , L.aetiopica and L. infantum .

44. MUCOCUTANEOUS LEISHMANIASIS it is characterized by variable type of and size of lesions. Initially there occurs simple skin lesions and there is involvement of mucosal membranes frequently in naso pharyngeal mucosa.

45. VISCERAL LEISHMANIA (KALA AZAR) I t is caused possibly by 3 related species of leishmania . The onset is inscidious and Incubation period is 2-6 months. Symptoms are, Irregular fever, malaise, loss of weight, weakness dry and pigmented skin, edema , epistaxis, severe anaemia , leucopenia , thrombocytopenia.

46. LABORATORY DIAGNOSIS SPECIFIC TESTS Microscopy: Specimen is smeared on clear glass slide, fixed with methyl alcohol and stained with Geimsa stain and leishmania bodies are demonstrated . C ulture : NNN ( Novy,Mac Neal and Nicolle) medium Brain heart infusion agar medium Grace insect medium or Tobie’s medium

47. Serological test : Include ELISA, CFT, indirect immunofluroscence and hemagglutination test.

48. NON-SPECIFIC TESTS TLC- Shows leucopenia DLC- S hows Neutropenia with lymphocytosis and monocytosis WBC:RBC Ratio-1:2000 ( NORMAL RANGE IS 1:750) Naplier aldehyde test : in this test 1 ml of patients serum is mixed with one drop of formalin (40%) and incubated at room temperature. Gel formation indicates positive test.

49. OTHER TESTS ARE, Leishmanian skin test Animal inoculation test

50. TREATMENT Glucantime , pentostan , allopurinol and amphoterecin B are the drug that are effective.

51. TRANSMISSION Through the bite of sand flies

52. PREVENTION Use of mesh doors, mosquito nets and repellants. Insecticidal sprays.

53. SPROZOA

54. There are four types of parasites that are causing the malarial disease. Plasmodium vivax Plasmodium falciparum Plasmodium malariae plasmodium ovale HABITAT: liver cells, erythrocytes and other organs.

55. LIFE CYCLE life cycle of plasmodium is completed in two hosts, man and female anopheles mosquito. Man act as an intermediate hosts while anopheles is a definitive host . Life cycle in man( schizogony or schizogenous phase) When an infected female anopheles mosquito bites a healthy person it introduces thousands of filarial parasites into human blood along with saliva. These parasites are motile and spindle shaped and is known as sporozoites (infective form of malarial parasite)

56. The sporozoite remains in the blood stream for few minutes to half an hour and then migrates to liver cells. Schizogony is divided into four phases: Pre erythrocytic phase/ cycle Exo - erythrocytic phase/ cycle Erythrocytic phase/ cycle Gametogony

57. Pre erythrocytic phase/ cycle T he sporozoite enters into the liver cells by its pointed ends, becomes round and is called as a tropozoites which enlarges and form schizont . The size of the schizont varies in different species and contains 20000 to 50000 merozoites .

58. when merozoites form in large number, the wall of the schizont and liver cells ruptures releasing merozoites in the space between liver cells and ultimately into blood stream.

59. Exo - erythrocytic phase/ cycle Some sporozoites on entering the liver cells do not undergo multiplication and enter into dormant phase. This resting or dormant phase of parasite is called hypnozoites .

60. A fter certain time period (usually 2 years) the hypnozoites reactivates and become tropozoites , then schizonts and finally release number of merozoites.These merozoites attack RBCs and cause relapse of malaria

61. Erythrocytic phase/ cycle The merozoites released by rupture of schizonts and liver cells after two or more cycles in liver may re enter blood stream and attack RBC’s. In RBC’s each merozoites form tropozoites and schizont . Depending upon the species, there may be 6-24 merozoites per RBC .

62. Gametogony Some merozoites formed in erythrocytic cycle develop into male and female gametocytes known as micro and macro gametocytes.

63. Life cycle in mosquito ( sporogony or sporogonic cycle ) When a healthy female Anopheles bites malarial patient, it sucks these gametocytes (male and female) along with blood . In stomach of mosquito, all the components of blood including RBCs are digested except gametocytes. The male gametocyte nucleus divides and 8 sperms are formed. In female gametocytes, nucleus does not divide.

64. only one sperm enters the female gametocytesand fuses with its nucleus forming zygote . The zygote elongates and forms a worm like stage known as ookinete . These ookinetes settles below the outer epithelium , develops a cyst wall and form oocyst .

65. Within the oocysts nucleus divides and form a large number of sporozoites . The wall of oocysts and stomach ruptures releasing sporozoites in the body cavity and enters to the salivary gland. The mosquito at this stage is infected and when it bite, it ejects these sporozoites into blood along with saliva and life cycle is repeated again.

66. Pathogenesis incubation period is different in different species. P. vivax 10-14 days P. ovale 10-14 days P. falciparum 10-14 days P. malariae : 18 days to 6 weeks

67. P .falciparum is most pathogenic to man. It invades RBCs, the cells are ruptured , pyrogens are released that cause characteristic chills . P vivax invades youngest RBCs where as P malariae invades only older RBCs . Clinical symptoms include; peaks in fever(cold, hot, sweating) splenomegaly and hepatomegaly.

68. The different types of fever produced are : 1)Benign tertian malaria fever 2) malignant tertian malaria fever 3) quartan malaria fever 4) quitodian malaria fever

69. Other complications are Cerebral malaria: it is characterized by high grade fever , coma,congestion and paralysis. Black water fever: it is characterized by sudden massive hemolysis followed by fever and hemoglobinuria . Algid malaria: it is characterized by cold clammy skin leading to peripheral vascular failure . Pernicious malaria: It is a life threatening condition that results due to anoxia sue to blockage of capillaries.

70. LABORATORY DIAGNOSIS Microscopy: peripheral blood film (thick and thin smear) is studied under microscope after staining with leishman technique . Serological test: ELISA Indirect haemagglutination Other test - radio immunoassay Agar gel diffusion test Dot blot assay Buffy coat method

71. TRANSMISSION Mosquito bite Blood transfusion Use of contaminated syringes among drug addicts.

72. TREATMENT Include use of quinine, chloroquin,primaquin , and mixture of sulfadoxin and pyrimethamine .

73. PREVENTION Chemical sprays Mosquito repellants Mesh doors and mosquito nets Biological control measures ( use f gambien fish which feeds on mosquito eggs )

74. CILIATA

75. BALANTIDIUM COLI HABITAT: large intestine of man, pigs and monkeys.

76. LIFE CYCLE They are largest ciliated protozoan parasites. The female worms liberate cysts which are passed in the stool. Infection occurs by the ingestion of these cysts with contaminated water and food. Then the colonies will be formed in the large intestine and the further growth and multiplication is taking over there. Mature cysts are passed with feces and cycle is repeated.

77. CLINICAL FEATURES The disease produced is commonly known as blantidiasis . Mostly it will be asymptomatic Some times symptoms occurs like Nausea, vomiting, diarrhea, abdominal pain and weight loss.

78. DIAGNOSIS MICROSCOPY: Cysts can be demonstrated in the stool specimens under the microscope.

79. TREATMENT The drug of choice is tetracycline with metranidazole and iodoquinol .

80. TRANSMISSION Contaminated water and food Unhygienic sanitation

81. PREVENTION Use clean, boiled purified water to drink. Improve personal hygiene Avoid contaminated food and water.