An outbreak of Schistosomiasis
(Bilharzia) infection following a
school trip to Malawi
Scottish Public Health Conference
November 2011
Ken Oates, Ola Blach, Steven
Bramwell, Grant Franklin
Case Presentation
• January 2011 , 17 year old male presented to
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urology with dysuria and visible haematuria
Cystoscopy – severe inflammation of the bladder
wall around blobs of parasitic eggs – Diagnosis
of urinary schistosomiasis ( S. Haematobium)
History of swimming in Lake Malawi during a
school trip previous summer
Initial investigation
• Health Protection team notified by Urologist
• Contacted Head teacher Secondary School and
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Education Service Highland Council
21 people on school trip to Malawi in June/July
2010 (17 pupils and 4 staff)
Canoeing trip on Lake Malawi (which included
some swimming!)
A full risk assessment was done in advance! and
school told by the adventure company that
particular area of the Lake was free from
infection (Cape McLear and Domwe Island)
Further investigation
• Contacted all 21 people directly and
advised them to have a screening test
• Arranged for blood tests – serology
• Informed local GPs – provided a written
briefing
• Agreed a lead local physician to see any
positives
Results
• 21 responded to our letters and saw their
GP or A&E (Glasgow, Dundee and
Australia!)
• 21 were screened
• 13 tested positive for Schistosoma
infection
• 2 were symptomatic (index and 1 other
male)
• 11 were asymptomatic
Results 2
• 10 were referred to Raigmore physician
• 3 seen by other specialists elsewhere
• All 13 treated with 2 doses of Praziquantel
• All fully recovered
Schistosomiasis (Bilharzia)
• A blood fluke infection with adult male and
female worms living within the mesenteric or
vesical veins for many years.
The Illness:
• Initial infection is often asymptomatic but itching
can occur at the site of entry. Two to four weeks
later fever, diarrhoea, cough, rash, abdominal
pain and hepato/splenomegaly may develop.
Schistosomiasis (Bilharzia)
3 types:
• S. haematobium causes haematuria. Long
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standing disease may cause ureteric obstruction
and renal failure.
S. mansoni usually presents with anaemia due to
blood loss and sometimes frank rectal bleeding.
Complications in long standing infection include
diarrhoea, cirrhosis and portal hypertension.
S. japonicum causes an illness similar to
S.mansoni but is often more severe. Long term
sequale includes bladder carcinoma,
hepatosplenomegaly and portal hypertension.
Schistosoma cercariae
Shistosoma haematobium
Schisto cases in Scotland
59-84 cases each year between 2005 and 2009
Schisto and Bladder cancer
• FIGURE . Bladder Cancer: Prevalence of Active Schistosomiasis (AS) by Age
and Age Distribution of Bladder Cancer (BC) in Egypt. Ibrahim and Khaled
National Cancer Institute. NIH Pub. No. 06-5873. Bathesda; MD; 2006.
Discussion
• High infection rate 13/21 (62%)
• Even following limited exposure
• Majority asymptomatic
• Other Scottish outbreaks 25-33% infected
• Between 2005 and 2009, 23% of
Scotland’s new cases of schisto were from
freshwater exposure in Malawi. ( 42% of
these in 15-24 year olds)
Discussion 2
• Scotland and Malawi “ Cooperation
Agreement” 2005
• Many school trips to Malawi
• High risk country/area
• Lack of awareness amongst pupils and
staff and schools
Actions – local
• Highland Council now has a new policy on
school trips overseas – “HC strongly
advises that all staff, pupils and volunteers
should avoid direct contact with water in
or from Lake Malawi.”
• Also provide advice re screening in those
who have been exposed and seeking early
help from GP if symptomatic on return
Travax – Malawi page
• Advice to travellers
• Travellers should avoid contact with fresh water
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in lakes, streams and rivers. Water for washing
can be treated by heating water to 50°C for five
minutes or leaving to stand for 48 hours.
If travellers are concerned that they may have
been exposed to schistosomiasis, they should
seek medical help on their return.
Further information can be found on the
Schistosomiasis Page.
Travax - Schisto page
• Recommendations for Travellers
• Avoid skin contact with fresh water in endemic
areas e.g. ponds, lakes and rivers. Swim only in
protected swimming pools or safe sea water.
Avoid drinking infected water. Wear protective
footwear when walking in soil, especially if it is
damp or water logged. Those who have been
knowingly exposed can be screened after return
but if there are no symptoms this should be
delayed for 6 weeks after the last possible
exposure so as to allow the time for the
development of antibodies.
Scotland Malawi Partnership
Swimming
• Infection from bilharzia (also known as schistosomiasis) occurs
when travellers paddle, swim or shower in fresh water which has
invasive larva. The risk of infection at Cape McLear is about
80%, but other beaches on the west coast of the Lake, and islands
also constitute a serious risk. Slow moving rivers and other lakes in
Malawi are also infected with this parasite. The risk may still be
present in the main beach hotels if shower water is drawn straight
from the Lake and not filtered or stored in holding tanks. The snails
that are the intermediate hosts are not confined to reedy areas.
Chinteche beach in the north appears safe.
Treatment does not work until the parasite has matured in the body
about 3 months after infection and first time treatment is not always
successful. If you do swim in the Lake you should apply 50%
DEET to all exposed areas after your shower in the evening
since this kills the parasites in the skin before they migrate.
Hotel pools are also to be avoided as there is uncertainty over
chlorination of the water.
Actions – national
• HPS Travax
• Scotland Malawi Partnership national
schools and volunteers guidance will be
amended shortly
• Publication
References
• 1. An outbreak of Schistosomiasis in travellers returning
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from endemic areas – the importance of rigorous tracing
in peer groups exposed to risk of infection. Journal of
Public Health. IN PRESS November 2011.
2. Redman C, Spence G, Smith H, Smith K. Travel
medicine: Schistosomiasis in Scotland 2005-2009. HPS:
Surveillance Report 2010; 44: 24-26.
3. Travax www.Travax.nhs.uk
4. Scotland Malawi Partnership
www.scotland-malawipartnership.org
Acknowledgements
• Ola Blach, Stephen Bramwell, Urology
Dept, Raigmore Hospital, Inverness
• Grant Franklin, Dept of Medicine,
Raigmore Hospital, Inverness
• Scottish Parasite Diagnostic Laboratory
Stobhill
• Health Protection Scotland Travel team
• HP team NHS Highland