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Flashcards in Lecture 18 Deck (95):
1

What type of organism are parasites?

eukaryotic organisms- animal cells

2

WHat is medical parasitology?

deals with eukaryotic organisms that cause disease among humans

3

Define protozoa and metazoa

protoza- unicellular
metazoa- multicellular

4

What are multicellular parasites known as

worms/Helminthes

5

What are the types of protozoa?

intestinal, urogenital, blood and tissue

6

What is Entamoeba Histolytica

Type of intestinal protozoa- known as ameba. Causes amoebic dysentry and liver abscess in humans

7

Who is the reservoir in Entamoeba Histolytica?

humans strictly

8

2 forms of Entamoeba Histolytica

vegetative form and durable form

9

What is the vegetative form?

active and motile- known as trophozoit- multiplies inside host

10

What is the durable form?

cyst- non motile and survive in environment for a few months

11

Where is vegetative form seen?

in intestinal, extra intestinal lesions and in diarrheal stool

12

Where is cystic form seen?

in non-diarrheal stool

13

Pathogenesis of Entamoeba Histolytica?

disease acquired by ingestion of cyst- oral/fecal route- contaminated food and water

14

Pathology of cyst

differentiate in ileum and tend to colonize in caecum and colon

15

Pathology of trophozoite?

invade colonic epithelium- secrete proteolytic enzyme that cause localized necrosis- little inflammation occurs

16

Is Entamoeba Histolytica world wide in distribution?

YES

17

Clinical manifestations of Entamoeba Histolytica

acute infection- dysentery, low abdominal discomfort, flatulence, tenesmus
chronic- occasional diarrhea, weight loss and fatigue

18

Define Amoebic liver abscess

Rt upper quadrant pain, weight loss, fever and tender enlarged liver

19

What happens if right lobe liver abscess bursts?

invade lung through diaphragm, causing lung abscess, anchovy sauce like pus

20

Diagnosis of Entamoeba Histolytica

stool examination may show cyst and vegetative forms- trophozoit contains ingested RBCs

21

Treatment for Entamoeba Histolytica

intestinal amoebiasis and liver abscess- Metronidazol/Tinidazol

22

Prevention of Entamoeba Histolytica

proper disposal of night soil/sanitation

23

Define Giardia lamblia

pear shaped trophozoit with 2 nuclei and 4 pairs of flagellum- suction disc which attaches to cell wall- cyst has 4 nuclei

24

Transmission of Giardia lamblia

ingestions- oral fecal route

25

What does Giardia lamblia cause?

excystation in duodenum, inflammation and mal absorption of protein + fat

26

What are the reservoirs for Giardia lamblia

human and animal - pass cyst in stool

27

Clinical features of Giardia lamblia

non bloody, foul smelling, diarrhea, nausea, anorexia, abdominal cramps, persists for week/months, no fever

28

Treatment for Giardia lamblia

Metronidazol

29

Define Trichomonas vaginalis

Pear shaped trophozoit with single nuclei, 4 flagellum + undulating membrane

30

Is there a vegetative and cystic form for Trich?

just vegetative form

31

Transmission of Trich

primarily located in vagina and prostate- sexual transmission only

32

Clinical manifestations of Trich

fowl smelling greenish vaginal discharge with itching and burning

33

Who is trich more symptomatic in?

sexually active women in their 30s- lower in post menopausal women

34

Lab diagnosis of Trich

wet mount of vaginal secretion or prostatic secretions shows pear shaped organism with typical herky movement

35

Treatment for Trich

Metronidazol

36

What does Plasmodium cause?

Malaria

37

What are the four species of Malaria?

Pl vivax, ovale, malariae, falciparum

38

What is the definitive host of Malaria?

blood sucking female anopheles mosquito

39

What is the intermediate host of Malaria?

human

40

Where does the parasite of Malaria multiply?

mosquitos and human

41

Cycle of mosquito multiplication in Malaria?

sexual cycle and form parasite known as sporozoite

42

Cycle of Human multiplication in Malaria

asexual multiplication take place in liver or RBCs and form parasite known Merozoits

43

Pathogenesis of Malaria

parasite infects and multiplies in RBCs which are destroyed by spleen causing enlargement of spleen

44

What does Malariae release?

merozoits every 72 hours- fever and chills occur every 4th day, others release every 48 hours re occurring every third day

45

Malaria caused by what is more severe?

falciparum - more RBCs effected leading to hemorrhage and necrosis of brain

46

What ethnicity is resistant to Malaria?

African Americans because they have sickle cell trait

47

Clinical manifestations of Malaria?

starts as abrupt fever, chills, head ache, myalgia- fever subsides then intense sweating- periodic fever
splenomegaly, anemia, falciparum

48

Why can relapse in malaria occur?

due to dormant form of parasite- known as hypnozoits

49

Lab diagnosis of Malaria

thick and thin smear of midnight blood during fever showing ring shaped organisms in RBCs

50

Treatment for Malaria

Chloroquin- kills hynozoits to prevent relapse

51

Prevention of Malaria

chemoprophylaxis with chloroquin

52

Definitive host for Toxoplasma Gondi

domestic cat

53

Intermediate host for Toxoplasma Gondi

man and other mammals like lamb and pig

54

How do cats get Toxoplasma Gondi infection?

through ingestion of cyst by eating raw meat - parasite multiplies in gut and excreted in feces

55

How do mammals get infected with Toxoplasma Gondi

mammals grace the soil contaminated with cats feces and gets infection

56

How do humans get infected with Toxoplasma Gondi?

ingestion of oocysts in undercooked meat/contaminated vegetables/ contact with cat feces- rapidly multiply and spread to brain, liver, lung, eyes

57

How are most Toxoplasma Gondi infections limited?

CMI and the organism persist in the tissues as cyst with out producing symptoms

58

Does transplacental transmission occur in Toxoplasma Gondi?

YES

59

Who is Toxoplasma Gondi asymptomatic in?

normal adults

60

What are symptoms of AIDS individuals with Toxoplasma Gondi?

chorio retinitis

61

What are symptoms of congenital infection with Toxoplasma Gondi?

may lead to abortion, still birth, neonatal disease with encephalitis, chorio retinitis, hepato splenomegaly, fever, jaundice

62

What is the most common cause of blindness in children in the US?

Toxoplasmosis Chorio retinitis

63

Lab diagnosis of Toxoplasma Gondi?

detection of IgM Ab in infants. Crescent shaped trophozoits/cysts in tissues can be seen under microscope

64

Treatment of Toxoplasma Gondi?

sulphadiazine, pyrimethamine for congenital toxoplasmosis

65

How is Pneumocystis Carini transmitted?

inhalation- opportunistic infection

66

Clinical features of Pneumocystis Carni

fever, dry cough, bilateral rales and rhonchi

67

What is used diagnostically to diagnose Pneumocystis Carni?

Xray shows glass appearance, microscopic examination of bronchial lay age/lung tissue biopsy

68

Medication for Pneumocystis

Trimethoprim and sulfamethoxazole

69

What does Trypanosoma cause?

Chagas disease in central and South America

70

How is Trypanosoma transmitted?

by reduvid bug- bites human on face and transmits parasites

71

Reservoirs of Trypanosoma disease?

humans and animals like cats and dogs

72

What does Trypanosoma gambiense cause?

sleeping sickness

73

What is the vector of Trypanosoma gambiense?

tsetse fly - endemic in Africa

74

What are the reservoirs for Trypanosoma gambiense?

human and domestic animals

75

Clinical features of Trypanosoma gambiense

lymph node enlargement followed by cyclical fever every 2 weeks, finally leading to encephalitis, coma and death

76

Treatment for Trypanosoma gambiense

suramin

77

Reservoirs for Leishmania donovani?

dogs, foxes, rodents

78

Vector for Leishmania donovani

Sand fly

79

What does Leishmania donovani cause?

disease known as Kala-azar. Sand fly bites humans and introduce infection, parasites multiply and infect reticulo endothelial system (liver, spleen, bone marrow)

80

Clinical manifestations of Leishmania donovani

intermittent fever, weakness, wait loss, enlargement of spleen, anemia with black discoloration of skin (black sickness), intermittent fever

81

Result of recovery of Leishmania donovani

results in permanent immunity, untreated cases become fatal

82

Treatment for Leishmania donovani

sodium stibogluconate

83

What three organisms are transmitted by same sand fly?

leishmania tropica, Leishmania mexicana, Leishmania brasilliensis

84

Reservoirs for Leishmania donovani?

dogs, foxes, rodents

85

Vector for Leishmania donovani

Sand fly

86

What does Leishmania donovani cause?

disease known as Kala-azar. Sand fly bites humans and introduce infection, parasites multiply and infect reticulo endothelial system (liver, spleen, bone marrow)

87

Clinical manifestations of Leishmania donovani

intermittent fever, weakness, wait loss, enlargement of spleen, anemia with black discoloration of skin (black sickness), intermittent fever

88

Result of recovery of Leishmania donovani

results in permanent immunity, untreated cases become fatal

89

Treatment for Leishmania donovani

sodium stibogluconate

90

What are reservoir of these three organisms?

forest rodents

91

What do the three Leishmania organisms cause?

skin and mucous membrane lesions with cartilage destruction

92

What does L tropica cause?

cause skin ulcer "oriental sore"

93

What does L mexicana cause

in americans it causes Bay sore

94

What does L brasiliensis cause?

In brazil and S America it causes a disease known as Espundia- disfiguring ulcerating lesions with granulomas similar to leprosy

95

Drug of choice for Leishmania?

Sodium Stibugluconate