7.16 Schistosoma

Question 1

Infective stage

Answer 1

Cercaria

Question 2

Causes urinary schistosomiasis

Established carcinogen, causing urinary bladder carcinoma

Answer 2

S. haematobium

Question 3

Causes intestinal schistosomiasis

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

Answer 3

S. mansoni

Question 4

Causes another form of intestinal schistosomiasis

Reported in 7 countries

Answer 4

S. intercalatum

Question 5

Oriental or Asiatic intestinal schistosomiasis

Endemic in 7 countries in the South-east Asia

Answer 5

S. japonicum

Question 6

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

Answer 6

S japonicum

Question 7

Egg has a prominent lateral spine

Answer 7

S mansoni

Question 8

Egg has a prominent terminal spine

Answer 8

S hematobium

Question 9

Intermediate host of S japonicum

Answer 9

Oncomelania hupensis quadrasi

Question 10

Definitive host

Answer 10

Human, carabaos, dogs, rodents, pigs

Question 11

Reservoir hosts

Answer 11

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

Question 12

Pathology of S. japonicum

Answer 12

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

Question 13

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

Answer 13

Katayama syndrome

Question 14

Chronic phase manifests as

Answer 14

Ascites, hepatosplenomegaly, bloody stools, cerebral schistosomiasis

Question 15

Low sensitivity in light infections

Answer 15

DFS

Question 16

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

Answer 16

FECT

Question 17

Gold standard

Qualitative and semi-quantitative detection of eggs

Answer 17

Kato-Katz

Question 18

Based on serum precipitation with lyophilized eggs

Cannot distinguish current and past infections

Answer 18

COPT (circumoval precipitin test)

Question 19

Qualitative detection of active infection

Uses urine

Answer 19

CCA/CAA (Circulating cathodic/anodic antigen)

Question 20

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

Answer 20

ELISA Ag test

Question 21

Use various schistosome Ags to detect antibodies

Can’t distinguish between current and past infections

Answer 21

ELISA Ab test

Question 22

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

Answer 22

PCR

Question 23

Oldest immunologic test

Use of purified schistosome Ag to detect previous exposure

Answer 23

Intradermal tests

Question 24

Most sensitive

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

Answer 24

Rectal imprint

Question 25

There is no positive stool examinations in the last five years

Answer 25

Near elimination

Question 26

Goals

Answer 26

<1% prevalence | 75-100% chemotherapy coverage

Question 27

Peak of prevalence

Answer 27

55-59

Question 28

Intensity of infection

Answer 28

5-14 years

Question 29

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

Answer 29

PZQ

Question 30

TOC for cerebral schistosomiasis

Answer 30

PZQ

Question 31

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

Answer 31

PZQ

Question 32

Targeted distribution of PZQ once a year in January

Answer 32

>5 y - 60/65 years old

Question 33

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

Answer 33

72%

Question 34

S. japonicum is possibly carcinogenic in humans, causing _____

Answer 34

Colorectal carcinoma

Question 35

High risk groups for Schisto

Answer 35

School children and young adolescents | Farmers and soldiers

Question 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

Answer 36

Morbidity control