Environmental HealthSchistosomiasis: 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

AgendaStakeholdersLearning ObjectivesWhat is

Schistosomiasis?Who is exposed?Transmission: Life

CycleGlobal Schistosomiasis

Burden/DistributionSymptomsDiagnosisTreatment

Prevention and Control

Prevalence in AfricaMorbidity and

MortalityRecommendationsQ and A SessionConclusionLessons Learned?ReferencesBibliography for

Further Reading

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 At the conclusion of this presentation, the viewer

will:Understand the etiology of schistosomiasisRecognize symptomsAble to diagnose the diseaseAcquire the knowledge to implement prevention,

control and treatment programsAcquire research based knowledge to assess the

risk, prevalence, and incidence of the disease in the community

Obtain health policy recommendations

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?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

Life Cycle of Schistosomiasis

Global Burden of SchistosomiasisMore 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 SchistosomiasisS. 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 CambodiaS. intercalatum: isolated areas in west and central AfricaSource:

Gyrseels, B., Polman , K., Clerinx, J., and Kestens, L. (2006). Human Schistosomiasis. The Lancet, 368(9541), 1106-1118

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

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

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.

DiagnosisLaboratory 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 suspectedUrine is examined when urinary

schistosomiasis is suspectedSource:CDC. (2008). Schistosomiasis. Retrieved April 10, 2009 fromhttp://www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.htm.

Diagnostic ResultsMicroscopy

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 DetectionRecent InfectionsPresence of AntibodiesPurified 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 SpecificityDependent 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 TreatmentNo 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 AfricaMost 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), 1504-1506WHO. (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 MortalityLow 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 RateCausing 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 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

ConclusionThe 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?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!!

Q & AAny questions from the audience?

ASANTE SANA

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 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 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.