Three Human Schistosomes specialization in targeting different organs of the human body (Essay Sample)

Three Human Schistosomes specialization in targeting different organs of the human body
Name
Institution
Introduction
Schistosomes are parasitic trematodes that cause and transmit diseases in humans in different global regions. There are different species of these trematodes based on their eggs morphology (Basch, 1981). Apparently, in humans, thee trematodes persistently causes schistosomiasis. The different species of these parasites differs in their host adaptability, their target human organs and as well as their attack mechanisms to these organs (Stephenson, 1987). Consequently, while understanding the nature of these parasite trematodes, it is important highlighting on their adaptability mechanisms, their migration mechanisms to the hosts and as well their attack mechanisms to humans. The paper is an outline of the three human schistosomes specialization in attacking different organs in the human body.
Outline
Types of Schistosomes
Schistosoma Japonicum
Schistosoma Mansoni
Schistosoma Haematobium
Difference between the Schistosome species
Schistosoma Japonicum
Definitive hosts
Humans
Ruminants (grazing animals that chew cuds such as cows and goats)
Carnivores (flesh feeding animals) (Stephenson, 1987)
Rodents (such as mice)
Insectivores (insect eating animals such as frogs and lizards)
Site of infection of the Shistosome in definitive hosts
Mesenteric veins of the small intestines
Methods of excreting their eggs from their hosts
Faeces
Snail intermediate host vectors and their habitats
Snail species
Oncomelania quadrasi (tropical freshwater snails)
Snail habitats
Terrestrial habitats
Scrub forests and rainforests
Aquatic habitats
Benthic regions
Geographical prevalence of the parasite species
South Eastern Asia
China
Taiwan
Philippines
Parasite morphology
The worms are wither yellow or yellow-brown
Sizes differ depending on the sex of the parasite where;
Male measures approximately 1.2cm by 0.54mm
Female size is approximately 2cm by 0.45mm
Spines and ridges cover the skin surface of the parasites
Have a strong oral sucker surrounding their mouths and a ventral sucker (acetabulum) further down the oral sucker (Basch, 1981)
Egg morphology of the Schistosome species
round eggs
Eggs with rudimentary lateral spine (Stephenson, 1987)
Schistosoma Mansoni
Definitive hosts (Agrawal, 2012)
Humans (sexual reproduction takes place in this host)
Rodents (such as mice)
Snails-an intermediate host where the parasite undergoes asexual reproduction
Site of infection of the Shistosome in definitive hosts
Mesenteric veins of the small intestines
Portal veins that drain the colons
Methods of excreting their eggs from their hosts (Rollinson, 1987)
Faeces
Snail intermediate host vectors and their habitats
Snail species
Biomphalaria pfeifferi (fresh water snail)
Snail habitats
Aquatic habitats
Lakes and ponds
Rivers and small streams
Terrestrial habitats
Tropical regions
Temperate habitats
Geographical prevalence of the parasite species
Africa
Southern America
Brazil
Venezuela (Agrawal, 2012)
Parasite morphology
Suckers
Oral sucker surrounds its mouth
Ventral sucker at the posterior end of the gut (Stephenson, 1987)
They do not have pharynx
Body size measurements
Male size is approximately 0.9cm long by 0.1cm wide
Female size is approximately 1.4cm long and 0.16mm wide
Female have a single ovary whereas males have multiple testes (approximately eight) (Basch, 1981)
Ovary located in the anterior part of the female parasite
Egg morphology of the Schistosome species
Oval eggs
Eggs have sharp lateral spines
Schistosoma haematobium
Definitive hosts
Humans (Agrawal, 2012)
Primates (animals such as monkeys and apes)
Snails-intermediate hosts
Site of infection of the Shistosome in definitive hosts
Veins in the urinary bladder infecting the urinary system of the host animal
Methods of excreting their eggs from their hosts
Urine
Snail intermediate host vectors and their habitats
Snail species
Bulinus truncatus,
Bulinus globosus
Bulinus senegalensis
Snail habitats
Terrestrial habitats
Rainforests
Savanna or grasslands
Scrub forests
Aquatic habitats
Rivers
Streams
Geographical prevalence of the parasite species
Southern Europe
Africa (Rollinson, 1987)
Middle East
Parasite morphology (Basch, 1981)
They are the shortest among the three parasites with the males being approximately 0.1cm long and female 0.15cm long
Suckers
Oral sucker that surrounds their mouths (Stephenson, 1987)
Ventral sucker posterior to the oral sucker
Males have gynecophoral canals where females attach themselves
Both nutrients and hormone exchange takes place through these canals
Female have one ovary unlike males that have an approximate of seven testes
In females, ovary located near the center of their body
Are heterothermic (Agrawal, 2012)
Egg morphology of the Schistosome species
Oval eggs
Eggs have sharp terminal spine
3. Similarities between the parasites
Body shape
They are ectothermic
Have a bilateral symmetry (Basch, 1981)
Sex dimorphism mechanisms
Males have multiple testes
Females have a single ovary
Mode of transmission and life cycle of Schistosomiasis in human hosts
Transmission of parasites between intermediate hosts and definitive hosts is through motile aquatic stages
Eggs produced by the female worms seek their way out of the hosts by penetrating through the gut and as well the bladder walls
When the excreted from the definitive hosts, the eggs actively seek intermediate hosts in aquatic environments (Rollinson, 1987)
The eggs hatch to free-swimming larvae miracidia
The miracidia infects the soft skin linings of the snail
Production of daughter protocytes takes place in the snail after two weeks of infection (Agrawal, 2012)
Protocytes release cercarie to the aquatic environment
Characteristics of cercarie
Rapid swimmers in water
attracted to skin secretions
fast penetration to host skin
loose their tails when pene...