Environmental Health

1
Environmental Health

• Schistosomiasis Is it a Neglected Tropical
  Disease (NTD)? What is it and Why Does it Matter
  in an African Community?
• A presentation to Communicable Disease
  Investigators
• by
• Richard Kara, Walden University, PhD Student
• May 4, 2009

2
Agenda

• Prevention and Control
• Prevalence in Africa
• Morbidity and Mortality
• Recommendations
• Q and A Session
• Conclusion
• Lessons Learned?
• References
• Bibliography for Further Reading

• Stakeholders
• Learning Objectives
• What is Schistosomiasis?
• Who is exposed?
• Transmission Life Cycle
• Global Schistosomiasis Burden/Distribution
• Symptoms
• Diagnosis
• Treatment

3
Stakeholders

• Ministries of Health (MOH)
• Health care Professionals (HCPs)
• Residents near freshwater bodies
• Parents and School Children
• Fishermen
• Community Hospitals
• Clergy and Community Leaders

4
Learning Objectives

• At the conclusion of this presentation, the
  viewer will
• Understand the etiology of schistosomiasis
• Recognize symptoms
• Able to diagnose the disease
• Acquire the knowledge to implement prevention,
  control and treatment programs
• Acquire research based knowledge to assess the
  risk, prevalence, and incidence of the disease in
  the community
• Obtain health policy recommendations

5
What is Schistosomiasis/Bilharzia?

• Caused by parasites (schistosomes).
• Results from contact with contaminated
  freshwater.
• Urinary and Intestinal forms most common.
• Source
• WHO. (2009). Schistosomiasis. Retrieved April
  16, 2009 From http//www.who.int/mediacentre/fact
  sheets/fs115/en/

6
Who is Exposed?

• Travelers to endemic nations (such as Peace Corps
  or tourists who swim in freshwater).
• Residents of endemic nations who live near
  freshwater bodies such as lakes, streams, rivers,
  etc.
• School age children are at greatest risk because
  of engagement in activities such as fetching
  water from rivers or streams for family use.
• Fishermen
• Source
• Carter Center Schistosomiasis Control Program.
  (2009). Retrieved April 30, 2009 from
  http//cartercenter.org/health/schistosomiasis/ind
  ex.html

7
Transmission of Schistosomiasis
8
Life Cycle of Schistosomiasis
9
Global Burden of Schistosomiasis

• More than 200 million infections in some 74
  countries worldwide with Africa having half of
  the infections and Nigeria being most endemic
  nation in Africa.
• Loss of disability-adjusted life years.
• Maps of global distribution of Schistosomiasis
  endemic areas.
• Source
• WHO. (2009). Schistosomiasis. Retrieved April
  16, 2009 From http//www.who.int/mediacentre/fact
  sheets/fs115/en/ .

10
Global Distribution of Schistosomiasis

• S. mansoni sub-Saharan Africa, northern Brazil,
  Surinam, Venezuela, the Caribbean, lower and
  middle Egypt, Arabic peninsula.
• S. haematobium sub-Saharan Africa, Nile valley
  in Egypt and Sudan, the Maghreb, the Arabian
  peninsula
• S. japonicum central lakes and River Yangtze in
  China, Mindanao, Leyte, and areas in Philippines
  and Indonesia
• S. mekongi central Mekong Basin in Laos and
  Cambodia
• S. intercalatum isolated areas in west and
  central Africa
• Source
• Gyrseels, B., Polman , K., Clerinx, J., and
  Kestens, L. (2006). Human Schistosomiasis. The
  Lancet, 368(9541), 1106-1118

11
Source Human Schistosomiasis. The Lancet,
368(9541), 1106-1118Map of Global Distribution
of Schistosomiasis
12
Global Distribution of Schistosomiasis Endemic
Areas. Map obtained from CDC website
http//wwwn.cdc.gov/travel/yellowBookCh4-Schistoso
miasis.aspx
13
Symptoms

• Onset of infection rash or itchy skin. Most
  people do not have symptoms at all early in the
  infection phase.
• 1-2 months fever, chills, cough, muscle aches
• Urinary Schistosomiasis Scarred tissues of the
  bladder, ureters, and kidneys. Bladder cancer is
  common in advanced cases.
• Intestinal Schistosomiasis enlarged liver,
  lungs, and spleen. Blood in stool due to
  hypertension of blood vessels. Varicose veins in
  esophagus bleed in advanced cases.
• Source
• CDC. (2008). Schistosomiasis. Retrieved April 10,
  2009 from
• http//www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.h
  tm.

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Diagnosis

• Laboratory diagnosis urine or stool samples can
  be tested for presence of schistosomiasis causal
  parasites.
• Samples are microscopically examined for presence
  of eggs.
• Stool examined when intestinal schistosomiasis is
  suspected
• Urine is examined when urinary schistosomiasis is
  suspected
• Source
• CDC. (2008). Schistosomiasis. Retrieved April 10,
  2009 from
• http//www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.h
  tm.

15
Diagnostic Results

• Microscopy
• Eggs of S. mansoni in unstained wet mounts. 
  Images courtesy of the Wisconsin State Laboratory
  of Hygiene.
• S. mansoni eggs have a characteristic shape with
  a lateral spine close to the posterior end of the
  egg (as shown above). S. haematobium has a
  terminal spine, and S.japonicum has a small
  lateral spine.
• Source
• CDC, 2008). Schistosomiasis. Retrieved April
  10, 2009 from http//www.dpd.cdc.gov/dpdx/HTML/Sch
  istosomiasis.htm.

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Diagnosis by Antibody Detection

• Recent Infections
• Presence of Antibodies
• Purified adult schistosome antigens are used.
• FAST-ELISA testing method using S. mansoni adult
  microsomal antigen (MAMA) is used for serum
  specimens.
• A detection of more than 9 units/micro liter
  serum indicates infection.
• Source Tsang ,V.C., Wilkins, P.P. (1991).
  Immunodiagnosis of schistosomiasis. Screen with
  FAST-ELISA and confirm with immunoblot. Clin Lab
  Med. 11(4), 1029-39.

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Test Sensitivity and Specificity

• Dependent on test procedure and antigen
  preparations (crude, purified etc).
• S. mansoni has a sensitivity of 99
• S. haematobium is 95
• S. japonicum is less than 50
• Specificity for detection of schistosome
  infection is 99
• Source
• Tsang ,V.C., Wilkins, P.P. (1991).
  Immunodiagnosis of schistosomiasis. Screen with
  FAST-ELISA and confirm with immunoblot. Clin Lab
  Med. 11(4), 1029-39.

18
Prevention and Treatment

• No vaccine approved.
• Controllable with Praziquatel.
• Prevention measures
• Avoid activities such as swimming, wading, and
  other contact with freshwater in nations listed
  as endemic for the disease. Water should be
  boiled before use. Use of fine filter mesh can
  limit spread of infection.
• Chlorination of water especially swimming pools.
• Causal parasite is rarely infective after 48
  hours. Therefore allowing bathing water to stand
  for at least 2 days can substantially reduce
  possibility of infection.
• Source
• Gyrseels, B., Polman , K., Clerinx, J., and
  Kestens, L. (2006). Human Schistosomiasis. The
  Lancet, 368(9541), 1106-1118.

19
Prevalence in Africa

• Most prevalent in sub-Saharan Africa with an
  estimated 100 million infections (WHO, 2009).
• Prevalence rates among local populations can
  exceed 50 in highly endemic nations (Deganello
  et al, 2007).
• Estimated 85 of people infected wordwide are
  living with the disease in Africa (Engels, et al,
  2002)
• Source
• Deganello, R., Cruciani, M., Beltramello, C.,
  Otine,D., Oyugi, V., and Montresor, A. (2007).
  Schistosoma hematobium and S. mansoni among
  Children, Southern Sudan. Emerg Infect Dis (EID),
  13(10), 1504-1506
• WHO. (2009). Schistosomiasis. Retrieved April
  16, 2009 from http//www.who.int/mediacentre/fact
  sheets/fs115/en/
• Engels, D., Chitsulo, L., Montresor, A., and
  Saviolli, L. (2002). The Global Epidemiological
  Situation of Schistosomiasis and New approaches
  to Control and Research. Acta Trop, 82(2), 139-46

20
Morbidity and Mortality

• Low Mortality Rate
• 150,000 deaths per year from non-functioning
  kidney caused by S. haematobium.
• 130,000 deaths per year from haematemesis caused
  by S. mansoni.
• High Morbidity Rate
• Causing debilitating illness among the infected
  population.
• Over 100 million infections in Africa with
  sub-Saharan Africa having highest disease burden
  estimated at 70 million.
• Source
• Marieke, J. Van der Werf., Sake, J. de Vlas.,
  Brooker, S., et al. (2003). Quantification of
  Clinical morbidity associated with schistosome
  infection in sub-Saharan Africa. Acta Tropica,
  86(2-3), 125-139

21
Recommendations

• Community engagement
• Participation and commitment from the community
  will maximize impact and resource use.
• Political will and commitment.
• Governments through MOH should fund prevention
  and treatment programs
• Training and continuing education.
• Basic grassroots training of the community
  population and continuing medical education (CME)
  for HCPs
• Evidence based scientific research
• Studies will provide evidence to adjust,
  implement, and manage programs. Academic research
  will provide new discoveries into the disease and
  treatment modalities
• Surveillance system
• Well developed systems will provide better
  monitoring of progress, and detection of
  deficiencies in order to take corrective action

22
Conclusion

• The literature suggests that schistosomiasis is a
  public health problem that needs immediate
  attention, especially in sub-Saharan Africa.
• True prevalence is underestimated due to lack of
  representative data, suggesting more field
  studies are needed.
• Active role by HCPs and participation of the
  local population is critical in prevention
  efforts in order to reduce incidence rates.
• Because the intermediate hosts (snails) can be
  reduced but not eliminated, regular and long term
  re-treatment should be part of the prevention and
  control strategy.

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WHAT DID WE LEARN?

• Shistosomiasis is a disease caused by parasites
  that live in freshwater in tropical climates.
• Globally 280, 000 people are estimated to die
  every year from the disease. At least 120 million
  have symptoms of the disease. About 20 million
  have serious symptoms.
• Over 200 million worldwide are infected.
• There are simple tests to diagnose the disease.
• There are treatments available, widely used is
  the drug praziquantel.
• PREVENTION REMAINS KEY!!

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Q A

• Any questions from the audience?

25
ASANTE SANA
26
References

• Deganello, R., Cruciani, M., Beltramello, C.,
  Otine,D., Oyugi, V., and Montresor, A. (2007).
  Schistosoma hematobium and S. mansoni among
  Children, Southern Sudan. Emerg Infect Dis (EID),
  13(10), 1504-1506. Retrieved April 3, 2009 from
  http//www.cdc.gov/EID/content/13/10/pdfs/1504.pdf
  .
• Abel, L., and Dessein, A.J. ( 1998). Genetic
  Epidemiology of Infectious Diseases in Humans
  Design of Population- Based Studies . Emerg
  Infect Dis, 4(4), 593-603. Retrieved April 14,
  2009 from http//www.cdc.gov/ncidod/eid/vol4no4/ab
  el.htm .
• Tsang ,V.C., Wilkins, P.P. (1991).
  Immunodiagnosis of schistosomiasis. Screen with
  FAST-ELISA and confirm with immunoblot. Clin Lab
  Med. 11(4), 1029-39.
• Savioli, L., Albonico, M., Engels, D., Montresor,
  A. (2004). Progress in the prevention and
  control of schistosomiasis and soil-transmitted
  helminthiasis. Parasitol Int.,53(2), 103-13.
• CDC (2008) Division of Parasitic Diseases
  Parasitic Disease Information Schistosomiasis.
  Retrieved April 16, 2009 from http//www.cdc.gov/n
  cidod/dpd/parasites/schistosomiasis/factsht_schist
  osomiasis.htm.
• CDC. (2008). Schistosomiasis. Retrieved April 10,
  2009 from http//www.dpd.cdc.gov/dpdx/HTML/Schisto
  somiasis.htm.
• Marieke, J. Van der Werf., Sake, J. de Vlas.,
  Brooker, S., et al. (2003). Quantification of
  Clinical morbidity associated with schistosome
  infection in sub-Saharan Africa. Acta Tropica,
  86(2-3), 125-139
• Gyrseels, B., Polman , K., Clerinx, J., and
  Kestens, L. (2006). Human Schistosomiasis. The
  Lancet, 368(9541), 1106-1118.
• WHO (2009). Initiative for Vaccine Research
  (IVR) Shistosomiasis. Retrieved April 15, 2009
  from http//www.who.int/vaccine_research/diseases
  /soa_parasitic/en/index5.html
• Engels, D., Chitsulo, L., Montresor, A., and
  Saviolli, L. (2002). The Global Epidemiological
  Situation of Schistosomiasis and New approaches
  to Control and Research. Acta Trop, 82(2), 139-46
• Carter Center Schistosomiasis Control Program.
  (2009). Retrieved April 30, 2009 from
  http//cartercenter.org/health/schistosomiasis/ind
  ex.html.
• CDC. (1990).Acute Schistosomiasis in U.S.
  Travelers Returning from Africa. MMWR, 39(9),
  141-142 and 147-148.
• WHO. (2009). Schistosomiasis. Retrieved April 16,
  2009 From http//www.who.int/mediacentre/factshee
  ts/fs115/en/

27
Bibliography for Further Reading

• World Health Organization (2003). The control of
  schistosomiasis. Second report of the WHO Expert
  Committee. World Health Organ Tech Rep Ser., 830
  1-86.
• CDC. (1993). Schistosomiasis in U.S. Peace Corps
  volunteers Malawi, MMWR Morbid Mortal Wkly
  Rep., 42565-70.
• Cetron ,M.S., Chitsulo, L., Sullivan, J.J.,
  Pilcher, J., Wilson, M., Noh, J., et al.
  (1996).Schistosomiasis in Lake Malawi. Lancet.
  348 (9037), 1274-1278.
• Istre ,G.R., Fontaine, R.E., Tarr, J., Hopkins,
  R.S. (1984). Acute schistosomiasis among
  Americans rafting the Omo River, Ethiopia. JAMA
  ,251 (4), 508-10.
• CDC. (1984). Acute schistosomiasis with
  transverse myelitis in American students
  returning from Kenya. MMWR 33 (31), 445-7
• Magnussen, P. (2003). Treatment and re-treatment
  strategies for schistosomiasis control in
  different epidemiological settings a review of
  10 years experiences. Acta Tropica, 86(2-3),
  243-254

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Bibliography for Further Reading

• Khoury, M.J., Beaty,T.H., Cohen, B.H. (1993).
  Fundamentals of Genetic Epidemiology. New York
  Oxford University Press
• Dessein, A., Abel, L., Couissinier, P., Demeure,
  C., Rihet, P., Kohlstaedt, S., et al. (1992).
  Environmental, genetic, and immunological factors
  in human resistance to Schistosoma mansoni.
  Immunol Invest, 21 (5), 423-53
• Abel, L., Demenais, F., Prata, A., Souza, A. E.,
  and Dessein, A. (1991). Evidence for the
  segregation of major gene in human
  susceptibility/resistance to infection by
  schistosoma mansoni. Am J Hum Genet, 48 (5),
  959-70.
• WHO (2004) Publications by KE Mott Chapter 12
  Schistosomiasis. Retrieved April 14, 2009 from
  http//whqlibdoc.who.int/publications/2004/9241592
  303_chap12.pdf.