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Environmental Health

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Title: 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.

14
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.

16
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.

17
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.

23
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!!

24
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

28
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.
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