1.                Synonyms:

 

v                                Bilharziasis

v                                Snail fever

v                                Katamaya fever

 

 

2.                Causative Schistosomes/ Blood flukes /Flatworms

 

v                                Schistosoma Haematobium

v                                Schistosoma Mansoni

v                                Schistosoma Japonicum

v                                Schistosoma Intercalatum

v                                Schistosoma Matthee

v                              Schistosoma Mekongi

 

3.                Facts

Schistosomiasis is the second most common parasitic disease in the world today, after malaria.

4.                Infective dose

Not known

     5.      Incubation period

2-6 weeks after exposure, although some references say 2-3 weeks.

6.     Transmission

 

This parasitic infection is acquired by swimming, wading, bathing, or

washing in fresh water that contains snails and that have been

contaminated by feces or urine carrying parasite eggs from

infected persons, in endemic regions. See” Life Cycle” (Annex I)

and Global Distribution of Schistosomiasis (Annex 11) for endemic

regions.

    7.     Preventive Measures

    

·        Travellers should be advised to avoid fresh-water contact in endemic areas. See” Global Distribution of Schistosomiasis” (Annex II).

·        Vigorous towel drying after accidental exposure to fresh-water in endemic Countries may help, but travellers should advise their Health Professionals upon return of their accidental exposure so that appropriate screening tests be ordered and /or a clinical evaluation be performed.

·        Heating bathing water to 50 degrees Celsius or 150 degrees Fahrenheit for 5 minutes or treating the water with chlorine in a manner similar to the precautions recommended for preparing drinking water will destroy cercariae and should make water safe. 

·        If swimming in pools in endemic countries, make certain that these pools are sufficiently chlorinated.

·        Filtering water with paper coffee filters can also be effective in removing               cercariae from bathing water.

·        Otherwise, travellers should be advised to allow bathing water to stand for 3 days since cercariae rarely survive longer than 48 hours.          

 

 

8.             Clinical manifestations

-          

·        Many acute infections are asymptomatic.

·        Most common acute symptoms are fever, lack of appetite, weight loss,               abdominal pain, weakness, headaches, joint and muscle pain, diarrhoea(bloody), nausea, cough and / or blood in the urine.

·        Rarely, the central nervous system, producing seizures is attacked.

·        Chronic infections can cause disease in the lungs, liver, intestines, or bladder              or a combination of these.

·        Eventually, bladder cancer, kidney problems or serious complications of the              liver or spleen will appear depending on the type of schistosoma one was              exposed to.             

                  

 

9.             Treatment

 

·        The current drug of choice is Praziquantel which may reverse pathology in as little as six months after treatment.

·        However, the degree of recovery from the infection depends on the damage caused by the infection.

·        If extensive fibrosis has occurred this cannot be reversed and therefore permanent damage does occur.

·        Recently, it has been found that certain populations respond poorly to Praziquantel Treatment, perhaps due to not having been exposed to schistosomiasis before and their immune systems are not primed (McGill University).

 

 

 

 

 

         

            

 

     

 

 

 

 

 

 

 

 

 

 

 

 

Reference:CDC, LIFE CYCLE

   www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.htm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reference: WHO www.who.int/ctd/schisto/epidemio.htm