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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. Agenda. Stakeholders

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Environmental health

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


Agenda

Agenda

  • Stakeholders

  • Learning Objectives

  • What is Schistosomiasis?

  • Who is exposed?

  • Transmission: Life Cycle

  • Global Schistosomiasis Burden/Distribution

  • Symptoms

  • Diagnosis

  • Treatment

  • Prevention and Control

  • Prevalence in Africa

  • Morbidity and Mortality

  • Recommendations

  • Q and A Session

  • Conclusion

  • Lessons Learned?

  • References

  • Bibliography for Further Reading


Stakeholders

Stakeholders

  • Ministries of Health (MOH)

  • Health care Professionals (HCPs)

  • Residents near freshwater bodies

  • Parents and School Children

  • Fishermen

  • Community Hospitals

  • Clergy and Community Leaders


Learning objectives

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


What is schistosomiasis bilharzia

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/factsheets/fs115/en/


Who is exposed

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/index.html


Transmission of schistosomiasis

Transmission of Schistosomiasis


Life cycle of schistosomiasis

Life Cycle of Schistosomiasis


Global burden of schistosomiasis

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/factsheets/fs115/en/ .


Global distribution of schistosomiasis

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


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Source: Human Schistosomiasis. The Lancet, 368(9541), 1106-1118Map of Global Distribution of Schistosomiasis


Environmental health

Global Distribution of Schistosomiasis Endemic Areas. Map obtained from CDC website: http://wwwn.cdc.gov/travel/yellowBookCh4-Schistosomiasis.aspx


Symptoms

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.htm.


Diagnosis

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.htm.


Diagnostic results

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/Schistosomiasis.htm.


Diagnosis by antibody detection

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.


Test sensitivity and specificity

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.


Prevention and treatment

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.


Prevalence in africa

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/factsheets/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


Morbidity and mortality

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


Recommendations

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


Conclusion

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.


What did we learn

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?


Asante sana

ASANTE SANA


References

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/abel.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/ncidod/dpd/parasites/schistosomiasis/factsht_schistosomiasis.htm.

  • CDC. (2008). Schistosomiasis. Retrieved April 10, 2009 from http://www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.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/index.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/factsheets/fs115/en/


Bibliography for further reading

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., 42:565-70.

  • 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


Bibliography for further reading1

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/2004/9241592303_chap12.pdf.


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