Elimination of Schistosomiasis: Is it possible and how do we do it?

Elimination of Schistosomiasis: Is it possible and how do we do it?

Mike French

WHO Schistosomiasis Plan: 2012-2025Vision A world free of schistosomiasis

Goals• To control morbidity of schistosomiasis by

2020 • To eliminate schistosomiasis as a public

health problem by 2025 • To interrupt transmission in AMR, EMR,

EUR, SEAR and WPR and in selected AFR countries by 2025

Objectives • To scale up control and elimination activities in all endemic countries;

• To ensure an adequate supply of praziquantel and resources to meet the demand

WHO Schistosomiasis Plan: 2012-2025Vision A world free of schistosomiasis

Goals • To control morbidity of schistosomiasis by 2020

• To eliminate schistosomiasis as a public health problem by 2025

• To interrupt transmission in the Americas, the Eastern Mediterranean, Europe, South East Asia, Western Pacific, and in selected African countries by 2025

Objectives • To ensure an adequate supply of

praziquantel and resources to meet the demand

What is elimination?

What is elimination?Category Definition Ongoing

Control?Examples

Control Reduction of disease in given area until it is no longer a major public health burden

Yes Schistosomiasis (2020)

Elimination as a Public Health Problem

Reduction in the prevalence of disease below a certain pre-set threshold (e.g. 1%)

Yes Schistosomiasis (2025)Lymphatic filariasis (2020)Trachoma (2020)

Elimination of Transmission (True Elimination)

Stopping transmission in a given geographical area

Active surveillance

Schistosomiasis – selected areas (2025)Onchocerciasis in Latin America (2015)Onchocerciasis in 21 SSA countries (2020)

Eradication Global Elimination - Worldwide removal of all infections and transmission

No Smallpox (1978), Rinderpest (2011)Guinea Worm (2015)Polio (2020)


Control?Examples








Active surveillance





Control?Examples








Active surveillance





Control?Examples


Yes Schistosomaisis (2020)






Active surveillance




Already gone

On their waySmallpox (1978)

Rinderpest (2011)

Guinea Worm (2015?)Polio (2020?)

Control of Morbidity Elimination as a public

health problem Elimination/Interruption

of transmission

PCT 100% geographical and 75% national coverage

with PCT

Adjusted PCT and complementary

interventions recommended

Intensified PCT and complementary

interventions essential

Prevalence of heavy intensity infection <5%*

Prevalence of heavy intensity infection <1%*

Reduction of incidence of infection to zero

Up to 5-10 years from joining the group

Up to 3-6 years from joining the group

Up to 5 years from joining the group

* In all sentinel sites

What do we need to get there?

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Complementary Approaches

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Vaccine?

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Behaviour Change



Water, Sanitation, and Hygiene (WASH)

Jack Grimes*, Dr Michael R. Templeton*, Dr Wendy Harrison†

*Department of Civil and Environmental Engineering, Imperial College London†Schistosomiasis Control Initiative, School of Public Health, Imperial College London

[email protected]

Water and sanitation, and schistosomiasis: a systematic

review and meta-analysis

WASH Definitions

WAter

Image credits: Aubrey Wade/WaterAid/Panos

Image credits: WSSCC http://www.wsscc.org/resources/resource-photo/toilets-south-africa#3

Image credits: UNICEF, UNICEFBANA2011-01020Shafiqulhttp://www.unicef.bg/en/article/On-Global-Handwashing-Day-UNICEF-says-It-s-not-complicated-but-it-s-crucial/375

HygieneSanitation

Jack Grimes, Dr Michael R. Templeton, Dr Wendy Harrison

‘Safe’ water source associated with significantly less Schistosoma infection

Overall Schistosoma and water:OR = 0.53 (95% CI: 0.47, 0.61)


S. haematobium and water:OR = 0.57 (95% CI: 0.45, 0.71)

S. mansoni and water:OR = 0.53 (95% CI: 0.45, 0.63)

S. japonicum and water:OR = 0.37 (95% CI: 0.30, 0.46)

‘Safe’ water source associated with significantly less Schistosoma infection


S. mansoni and sanitation:OR = 0.59 (95% CI: 0.47, 0.73)

Sanitation associated with significantly less S. mansoni infection


S. haematobium and sanitation:OR = 0.69 (95% CI: 0.57, 0.84)

Sanitation associated with significantly less S. haematobium infection


Other Approaches: Snail Control and Behaviour ChangeS. haematobium elimination in Zanzibar

• Elimination of Schistosomiasis on Zanzibar (ZEST trial) – Lynsey Blair– S. haematobium– Randomized Control TrialThree arms:– Arm 1: MDA Alone (Control)– Arm 2: MDA plus Snail Control– Arm 3: MDA plus Behaviour Change

– Midpoint of study

Other Approaches: Snail Control, WASH, and Enhanced TreatmentS. mansoni elimination in Burundi/Rwanda

Randomized Control Trial:To be confirmed after schistosomiasis re-assessment4 armsArm 1: Control – Standard annual TreatmentArm 2: Enhanced treatment – Twice Yearly treatmentArm 3: Snail ControlArm 4: Water, Sanitation, and Hygiene

Burundi

Rwanda

S. haematobium elimination in NigerFollowing 6 years of sentinel sites

monitoring, Niger was classified as an ‘elimination’ ICOSA country

Re-Mapping/Impact Surveys to assess local elimination and use focal treatment in areas no longer eligible for treatment

Improving case detection at health centres & routine diagnosis

Snail surveys. Identifying schistosome hybrids and animal reservoirs

Innovative education activities such as mobile cinemas

Vaccines• Meetings convened by Gates

Foundation / National Institute of Health Meetings on the potential role of vaccines in elimination

• No vaccines currently available• Several candidates in development,

including one in Phase III trials, although several years off if at all

• Likely to be offer imperfect protection

Using Mathematical Models to Optimise the Use of Vaccines for

Schistosomiasis

Miss Arminder DeolDr Michael FrenchDr Deirdre HollingsworthDr James Truscott

:1. Modelling the impact of an actual/proposed vaccine in developmentModelling could give:Population impactCost-effectiveness

2. Using modelling to suggest the required characteristics of a vaccineModelling could give:Level of efficacy requiredWhich section of the life-cycle would be best to targetWhat proportion of the population to targetWho to target in the population

Arminder Deol et al

Using Mathematical Models to Optimise the Use of Vaccines for Schistosomiasis

New Approaches

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Extending Current Approaches – Closing the treatment gap

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Increasing treatment



How do we close the treatment gap?• Getting drugs to people – ensuring treatment

coverage is as high as possible• Expanding the target population

Closing the Treatment Gap – Doing the simple things well

NTD Supply Chain Forum• Coalition of partners engaged in the donation of NTD drugs• Aim to identify and overcome challenges related to shipping

and in-country transportation• Pharmaceutical Companies: GSK, Johnson and Johnson,

Merck & Co., Merck KGaA, Eisai, Pfizer• WHO• global logistics company DHL• NGOs Children Without Worms and International Trachoma

Initiative• Major body of work – overcoming clearance of drugs

through customs and into national warehouses

Closing the Treatment Gap – Doing the Simple things well

NTD Supply Chain Forum

Project Last Mile• If you can get Coca Cola anywhere in the world why not

life-saving medicines?• Launched in 2009• Partnership between Coca Cola, Gates’ Foundation,

Global Fund to fight Aids, Tb, and malaria• Yale’s Global Health Leadership Institute, Accenture

Development Partners, and the Global Environment and Technology Foundation

• Expanded to 10 African countries within five years


Project Last Mile


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Closing the Treatment Gap – Young Children

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Under 6s Age-groups targeted for treatment




• Understanding the role that young children play in transmission.

• Carried out by Arminder Deol and Judy Fernandes in our team

• Full age-intensity profiles in Liberia and Uganda

• Combined with modelling work being carried out by the NTD Modelling Consortium


Summary and way forward

All stages towards elimination suggest there is a need for complementary interventions: • Need an evidence base for which are

the most appropriate interventions in different settings and species

• Meaningful collaboration with other sectors – how is this best achieved?

• Doing the basics well (and better)

Thank you

www.imperial.ac.uk/sci@[email protected]

Documents

Elimination of Schistosomiasis: Is it possible and how do we do it?