Urinary Schistosomiasis

Question 1

The habitat of S.haematobium is……, its IH is……., its DH is……

Answer 1

Pelvic & vesical venous plexus, rarely mesenteric
Bulinus trancatus
Human

Question 2

Schistosomulae must reach……to develop into adults.

Answer 2

Portal circulation

Question 3

How do eggs escape from vessels to lumen of bladder?

Answer 3

I. Tearning action of egg-spine
II. Pressure within the venule
III. Lytic secretions of miracidium inside eggs

Question 4

EGGs hatch & produce……which must penetrate snail IH within ……..where they develop into…….

Answer 4

Miracidia
8-12 hrs
Sporocysts

Question 5

Describe mode of infection & infective stage of urinary schistosomiais

Answer 5

Furcocercus cercaria penetrate human skin during contact with infected water or rarely buccal mucosa when drinking infected water.

Question 6

Mention manifestation of:
1. Stage of invasion
2. Schistosomular migration

Answer 6

1. Swimmer’s itch, itching, dermatitis, rash, papules, Hges
2. In lung & liver results in fever, wheezes, hemoptysis, hepatomegaly, anorexia, eosinophilia, leukocytosis

Question 7

Mention stage of schistosomiasis chch by:
1. Granuloma formation
2. Inc serum immune complexes
3. Katayama fever

Answer 7

1. Stage of maturation & egg deposition
   2&3. Early acute schistosomiasis (part of 1)

Question 8

List manifestations of the stage of egg retention

Answer 8

Granuloma formation, ulceration, fibrosis, in bladder, ureter & genital organs leading to cytitis, calcification, ulceration, polyp & stone formation, cancer, hydroureter, hydronephrosis, pyoureter, pyonephrosis, sterility.
Cor-pulmonale may occur if eggs escape to pulmonary circulation. Pulmonary arteriolitis & HTN, endarteritis obliterans in pulmonary artery.

Question 9

Explain: Although patients affected with schistomiasis are resistant to subsequent infection by cercariae they are still harbouring adults

Answer 9

The adult worms are coated with host molecules that allow them to evade the immune system while invading parasites has not yet acquired a protective coat of host antigen.

Question 10

List mechanisms of immune evasion of schistosomes

Answer 10

1. Acquire host antigen on its surface (antigenic mimckry)
2. Host-like antigen produced by parasite
3. Changing of tegument very quickly
4. Parasite may inactivate or downregulate immue effectors

Question 11

Describe routine urine examination in case schistosomiasis

Answer 11

Hematuria (80%) proteinuria, cells esp eosinophils

Question 12

Mention direct parasitological methods of diagnosis of schistosomiasis

Answer 12

1. Sedimentation method
2. Urine filtration techniques (quantitative)

Question 13

Indirect immunidiagnosis is useful in……

Answer 13

Early infection, chronic infection (closed lesions), follow-up of treatment

Question 14

Treatment of choice of schistosomiasis is…..

Answer 14

Praziquantel

Question 15

Molluscicides include…….

Answer 15

Copper sulphate , bayluscide (more effective, affects all larval stages)