Schistosoma haematobium - Introduction, Classification, History, Habitat, Morphology

Introduction of Schistosoma haematobium

Schistosoma haematobium is a parasitic blood fluke and the causative agent of vesical or urinary schistosomiasis. The flukes live in the vascular system (portal blood) of humans and other vertebrates. The characteristics of Schistosoma include:

• unisexual (diecious) – male holds female in the gynecophoral canal

• in males, the number of testes varies from 4 to 8

• in females, Laurer’s canal is absent

• eggs are non-operculate, fully embryonated when laid

• cercariae are pharyngeal cause infections in the host by penetration through unbroken skin

• muscular pharynx and the encysted metacercarial stage is absent

Classification of Schistosoma haematobium

Kingdom: Animalia

Phylum: Platyhelminthes

Class: Trematoda

Order: Diplostomida

Family: Schistosomatidae

Genus: Schistosoma

Species: S. haematobium

History of Schistosoma haematobium

Bilharz in 1851 first discovered adult Schistosoma haematobium from the mesenteric veins of Cario native. He also demonstrated terminal-spined eggs of the parasite in the urine of native laborers with haematuria. In 1925, Leiper described the life cycle of the blood fluke.

Habitat of Schistosoma haematobium

Schistosoma haematobium lives in the venous plexuses of the vena cava system that drains the urinary bladder, pelvis, and ureter. Both male and female flukes are found together.

Morphology of Schistosoma haematobium

Adult Form

• the body is covered with integument which protects the fluke from the immune system of the host

• unisexual (diecious) – male holds female in the gynecophoral canal

• the male is short and stout (1cm-1.5cm in length and 0.9mm in breadth)

• female is 2cm in length and 0.25mm in breadth

• female can lay around 20-200 terminal spined eggs per day

• the life span of an adult is more than 20-30 years

• the body surface of the male is finely tuberculate

• in males, the number of testes varies from 4 to 6 and is arranged in a cluster

• the ovary is positioned in the middle of the female body

• about 20-30 eggs are present in the uterus

• does not multiply in man

Egg

• measures 110μm to 170μm in length and 40μm to 70μm in breadth

• elongated, oval-shaped, yellowish brown and non-operculated

• identifying feature of Schistosoma haematobium egg is a terminal spine at the posterior end

Cercaria

• the infective form of Schistosoma haematobium

• elongated oval body

• measures 150μm in length and 60μm in breadth

• has two suckers and a bifurcated elongated tail measuring 200μm in length

• the entire body is covered with extremely spine-like projections

• short-lived- lives only 24 hours to 72 hours

• male and female cercaria are morphological to other Schistosoma species

• oxophilic in nature