Schistosoma

sources:

1)Internet
: schistosomiasis
: welcome trust
:genito-urinary parasites
2)Zagazig university, foundation in parasitology


Schistosomiasis life cycle | Wellcome Trust (click this link for animation = must see!!)


ok..jom berkenalan dgn Schistosoma lak:

~~~~Schistosoma is also known as BLOOD FLUKE!~~~~~~~

in affected man, they can causing cercarial dermatitis.

general characters of schistosoma:

1. oral & ventral suckers are little distance apart.
2. mouth leads to oesophagus, which divides infront of the ventral suckers,then reunite to form a single caecum.
3. adult male is flattened dorso-ventrally but folded on itself to form gynaecophoric canal. its cuticles covered with tubercles.
4. testes lie behind ventral sucker.
5. adult female is cylindrical. its cuticle is smooth
6. ovary is ovoid lies in front of union of the intestinal caeca.
7. oviduct proceeds anteriorly, it dilates to join the ootype.
8. vitelline gland are on either sides of the single caecum. Vitelline duct opens in ootype.
9. uterus proceeds from ootype to open by vagina in the genital atrium.

i) 3 types of species that affecting human:

• Schistosoma haematobium
• Schistosoma japonicum
• Schistosoma mansoni

ii) caused of schistosomiasis :

• by digenetic blood trematodes.

iii) General Distribution:

1. Schistosoma mansoni = Africa, Middle East, South America & Caribbean
   
2. Schistosoma haematobium = Africa, Middle East
3. Schistosoma japonicum = Far East

iv) Habitat :

1. S. haematobium = venous plexus of bladder, also in rectal venules.
2. S.japonicum = sup. mesenteric Veins (draining the small intestine)
3. S.mansoni = inf. mesenteric Veins (draining the large intestine)

v) transmission:

Host :

· Definitive host:

§ S.haematobium: man only

§ S. japonicum : Dogs, Cats, Sheeps, pig, goat, cows

§ S. mansoni : monkeys, chimpazees, rodents

· Intermediate Host:

§ Snails i) g. Bullinus = S.haematobium

Ii) g. Biomphlaria =S. mansoni

iii) g. Oncomelania=S. japonicum

eg : genus biomphlaria = S.mansoni

for more picture click here

Infective stage :

§ BIFURCATE CERCARIA swimming in water

· Diagnostic stage:

§ Characteristic EGG in URINE/ STOOL

vi) cell cyle:

vii) pathology and pathogenesis:

Pathological lesions in schistosomiasis result from EGG DEPOSITION IN TISSUES.

Eggs --> Granuloma formation (around tissue affected)--> Delayed hypersensitivity via cell-mediated immune response

1)Granuloma (formed of schistosome)--> cellular aggregation of eosinophils,monocytes,lymphocytes,neutrophils, and plasma cells--> fibroblast appearance--> fibrosis + obstruction of B.V

2)immuno-pathology: due to immune complex deposition in various tissues esp, kidney glomeruli. Immune complex is formed from antigen-antibody combination

Treatment: Until the 1970's, treatment of schistosomiasis was nearly as dangerous as the disease itself. Modern treatment is effective and without risk. Three new drugs have revolutionized treatment:

• Praziquantel - effective in the treatment of all forms of schistosomiasis, with virtually no side effects
• Oxamniquine - used exclusively to treat intestinal schistosomiasis in Africa and South America
• Metrifonate - effective for the treatment of urinary schistosomiasis

Modern diagnostic techniques are simple, easy to apply and cost very little. Although reinfection may occur after treatment, the risk of serious disease developing in the body organs has been greatly reduced, and it has been observed that there is a marked regression of lesions in young children following treatment of the infection. In the majority of localities where treatment is provided, the total number of cases is reduced within 18 to 24 months. In other localities, according to the local situation, the prevalence has been substantially reduced, and it is encouraging to note that no further intervention is required for intervals between 2 and 5 years.

To be effective, schistosomiasis control strategies should be adapted to the local epidemiological situation and caution must be taken when destroying freshwater snails using chemicals - particularly in terms of impact on the environment.

In 1983, the World Health Organization, in association with the health ministries of several endemic countries (Botswana, Egypt, Madagascar, Mauritius and Zanzibar), launched a massive programme to assess control methods. The findings of this programme are as follows:

• Single dose praziquantel is effective in reducing prevalence and in containing the disease
• Schistosomiasis treatment must be accompanied by health education.
• Praziquantel can be safely administered by primary healthcare teams
• It is almost always necessary to repeat the treatment, but the interval may be up to 5 years in some situations where transmission is low.
• A simple and rapid test for blood in the urine using a paper strip soaked in a reactive agent is more reliable than a microscopic examination, which can prove difficult in the field.

p/s: ok dats all for this week..next tyme kite ckp pasal drugs pulak insyaALLAH..
segala kekurangan harap dimaafkan..

btw: tolong doakan anak buah sy, adik shahrul Hisyam bin Samawi (2 1/2tahun), adik sekarang di NICU disebabkan spleen cancer,dysfuntioning kidney, metastasis-cancer spread up to vital parts.sekarang adik dah last stage (stage 4= life saving 50-50%)..
but i believe in ALLAH miracle..
jika hidup itu baik bagi adik shahrul Hisyam..
doakan sama-sama agar adik dapat sihat seperti sediakala..
tetapi andai kata kematian adalah yang terbaik untuknya..
doakan adik agar mendapat tempat dikalangan org2 yg beriman..
sesungguhnya perancangan ALLAH itu adalah yang terbaik dan terindah..
moga ditabahkan hati kami sekeluarga..
Al-Fatihah sebagai sedekah utk adik Shahrul Hisyam ..
moga2 sedekah ini dpt mengurangkan kesengsaraan yang dialaminya..

"YA ALLAH sungguh kami sayang akan ahli keluarga kami..akan tetapi..jika ENGKAU lebih menyanyanginya..kami redha YA ALLAH.. tabahkanlah hati kami ..kerana kami ini hambamu yang hina..lemah dari segala sudut..tabahkan kami ya ALLAH..tabahkan kami..tabahkan kami..ameen ya Rabb.."

~tears oozing out.. :( ~~minta tlg doakan adik shahrul hisyam kawan2..

Schistosomiasis

source : internet ABC DA SAUDE

SCHISTOSOMIASIS

What is it?

An infection caused by a parasitic worm of the Trematoda class. It occurs in diverse parts of the world in an uncontrolled fashion (endemic). In these places, the number of people with this parasitosis remains rather steady.

The parasites of this class are five, and vary as causative agent of the infection according to the world region. In our country, schistosomiasis is caused by the Schistossoma mansoni. The chief host and reservoir of this parasite is man, the eggs being disseminated in the environment from man´s feces and urine.

It also has an intermediate host, namely, the snails and slugs, in which the eggs reach the larval stage. This is spread especially in untreated waters, such as lakes, and infects man through the skin, causing skin inflammation. While in man, the parasite develops and settles down in the veins of the intestine and liver, causing their obstruction, this being the cause of most symptoms of the disease, which can be chronic and lead to death.

sorry its blurry..

How is it acquired?

The eggs eliminated by the urine and feces of contaminated individuals evolve to larvae in the water, these lodge and develop in snails. The snail releases the adult larva, which contaminates man on remaining in the water. In the human venous system, the parasites develop until reaching 1 to 2 cm in length, reproduce themselves and shed eggs. The parasite´s development in man takes about 6 weeks (incubation period), that´s when it takes on the adult and reproductive form already in its final habitat – the nervous system. The release of its eggs by man can last many years.

What does one experience?

At the moment of contamination a kind of allergic response may occur in the skin with itching and redness, triggered by the parasite´s penetration. This reaction occurs approximately 24 h after the contamination. After 4 to 8 weeks, there´s the appearance of fever, chills, headache, abdominal pains, lack of appetite, nausea, vomiting and dry cough.

While examining the parasitosis carrier, the doctor may find in this phase an enlarged liver and spleen as well as enlarged lymph nodes or lymphodenomegaly. These signs and symptoms usually disappear in a few weeks. Depending on the amount of worms, an individual can be a parasite carrier without any symptoms, or present over the months symptoms of the chronic form of the disease: fatigue, abdominal pain of the colic type with intermittent diarrhea or dysentery.

Other symptoms derive from the obstruction of veins in the spleen and liver with consequent enlargement of such organs and deviation of the blood flow that may cause from discomfort or pain in the left upper quadrant of the abdomen to vomiting with blood due to varices that are formed in the esophagus.

How is the diagnosis made?

To diagnose schistosomiasis the information about the suspect having been to an area where there are many disease cases (endemic area) is very important, in addition to the symptoms and signs described above (clinical condition). Feces and urine tests with eggs of the parasite or even small tissue samples from some organs (biopsy of the mucosa from the end of the intestine) are the ultimate exams. More lately, there are exams available that detect, in the blood, the presence of antibodies to the parasite that are useful in those cases of mild or symptom-free infection.

How is it treated?

The treatment of choice is with antiparasitic drugs, chemical substances that are toxic to the parasite. Currently there exist three groups of substances that eliminate the parasite, but the medication of choice is Praziquantel, which is taken in the form of pills, almost always during one day. That´s enough to eliminate the parasite, also getting rid of the dissemination of eggs into the environment. In those cases of chronic disease, the complications require specific treatment.

How to prevent it?

As it is a worldwide disease, endemic in several places (Arabic Peninsula, Africa, South America, and Caribbean), health public organizations (WHO – World Health Organization – and the Health Ministry) have specific programs for managing the disease. Basically, the strategies for managing the disease are based on:

	-Identification and treatment of carriers.
	-Basic sanitation (treated water and sewers), besides fighting the intermediate molluscan host.
	-Health education.