7.16 Schistosoma Flashcards Preview

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Flashcards in 7.16 Schistosoma Deck (36)
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1

Infective stage

Cercaria

2

Causes urinary schistosomiasis
Established carcinogen, causing urinary bladder carcinoma

S. haematobium

3

Causes intestinal schistosomiasis
Endemic in 53 countries (Africa, Eastern Mediterraneean, Caribbean, South America)

S. mansoni

4

Causes another form of intestinal schistosomiasis
Reported in 7 countries

S. intercalatum

5

Oriental or Asiatic intestinal schistosomiasis
Endemic in 7 countries in the South-east Asia

S. japonicum

6

The eggs have no spine but have a small lateral knob that adheres to the tissues

S japonicum

7

Egg has a prominent lateral spine

S mansoni

8

Egg has a prominent terminal spine

S hematobium

9

Intermediate host of S japonicum

Oncomelania hupensis quadrasi

10

Definitive host

Human, carabaos, dogs, rodents, pigs

11

Reservoir hosts

Cows, dogs, pigs, carabaos, field rats and monkeys

12

Pathology of S. japonicum

Granuloma reaction leading to ascites, potal hypertension (esophageal veins, peri-umbilical veins, hemorrhoidal veins), splenomegaly, cirrhosis

13

Acute phase of S japonicum infection following cercarial penetration
Urticara and diarrhea

Katayama syndrome

14

Chronic phase manifests as

Ascites, hepatosplenomegaly, bloody stools, cerebral schistosomiasis

15

Low sensitivity in light infections

DFS

16

Sedimentation method used to separate parasitic elements from fecal debris through centrifugation

FECT

17

Gold standard
Qualitative and semi-quantitative detection of eggs

Kato-Katz

18

Based on serum precipitation with lyophilized eggs
Cannot distinguish current and past infections

COPT (circumoval precipitin test)

19

Qualitative detection of active infection
Uses urine

CCA/CAA (Circulating cathodic/anodic antigen)

20

Based on the use of crude soluble egg antigens or soluble adult worm proteins
Complementary method in settings with low infection rates

ELISA Ag test

21

Use various schistosome Ags to detect antibodies
Can't distinguish between current and past infections

ELISA Ab test

22

Highly specific and sensitive, useful when both KK and serological tests are both negative

PCR

23

Oldest immunologic test
Use of purified schistosome Ag to detect previous exposure

Intradermal tests

24

Most sensitive
Useful for ruling out SCH in situations where both KK and serological tests are negative and SCH remains in doubt

Rectal imprint

25

There is no positive stool examinations in the last five years

Near elimination

26

Goals

<1% prevalence
75-100% chemotherapy coverage

27

Peak of prevalence

55-59

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Intensity of infection

5-14 years

29

Causes increased muscular activity followed by contraction, leading to spastic paralysis of worms and their detachment form vessel walls
Can cause tegumental damage

PZQ

30

TOC for cerebral schistosomiasis

PZQ

31

Adverse effect of this drug include abdominal discomfort, particularly pain and nausea, diarrhea, headache, dizziness and drowsiness

PZQ

32

Targeted distribution of PZQ once a year in January

>5 y - 60/65 years old

33

Goal to have ___ of households in endemic areas with sanitary facilities

72%

34

S. japonicum is possibly carcinogenic in humans, causing _____

Colorectal carcinoma

35

High risk groups for Schisto

School children and young adolescents
Farmers and soldiers

36

WHO recommends that the first objective should be for _____, to reduce consequences of these infections to a level that no longer constitutes a public health burden

Morbidity control