This presentation was given at a special Schistosomiasis, Soil-transmitted Helminthiasis at the WHO headquarters in Geneva on Nov. 30th 2016.

1. Can twice a year MDA accelerate schistosomiasis control:
biannual PZQ treatment why, when, who, where…and how?
Russell Stothard LSTM, UK e-mail: russell.stothard@lstmed.ac.uk

2. Is biannual treatment needed….yes (noting key demographic groups [DGs])
Why: PZQ does not prevent reinfection
Where: transmission dependant selection
Who: anyone with recurrent schistosomiasis
When: if intensification of treatment is needed
How: MDA (?x2), MDA + selective treatment of DGs
health system - ensuring +ve ‘access-seeking’

3. Control of schistosomiasis is not a static concept (Mott, 1987)
1998 Today…and preparing for next decade
SCORE
Ezeamama et al.

4. Control of schistosomiasis is not a static concept (Mott, 1987)
Setting broader needs for PZQ
- expanded coverage to all DGs
- lower prevalence thresholds
- shorter treatment cycles

5. In simple terms…twice the…drug…impact…acceleration…?headache
1
Annual Biannual
?previous interventions
Starting point 2
Annual Biannual
3
Annual Biannual … …. …. …
X
Annual ?change
1
Annual Biannual
2
Annual Biannual
3
Annual Biannual … …. …. …
X
Annual Biannual
100%
light
medium
heavy
< 30%
< 15%
Pro: better reduction in infection Con: complicated coverage statistics
can it be operationalised at sufficient scale?

6. Why: PZQ does not prevent reinfection
• R/S-PZQ is active against adult worms, NOT pre-mature worms within systemic circulation
• On re-exposure, further schistosome larva are acquired, accrue and mature to fecundity
• The schistosome’s lifecycle is much shorter than a calendar year AND doesn’t respect it
• PZQ efficacy lower in >>50% settings
[a proportional reduction still maintained?]
• Repeated dosing (4 or 6 weeks)
Stothard, Sousa-Figueiredo & Navaratnam (2013)

7. Great to see growing inclusion of PSAC (but not little adults)
Recommendations
A) Preschool-age children can be at high risk of schistosomiasis
and PZQ treatment should be made available to them.
B) PZQ can be administered during children health days/EPI.
C) Crushed or broken tablets can be used until a suitable child-
friendly paediatric formulation is developed/available.

8. Who: anyone with recurrent schistosomiasis (PSAC, SAC, Adults)
April 2013 – Trends in Parasitology

9. Table 5. Anaemia associated factors and corresponding multivariate adjusted
odds ratios at baseline
Associated Factor Adjusted OR (95% CI)
SIMI cohort
(n=570)
Anaemia
prevalence
68.8%
Age (months)
0 - 12 -
13 - 24 0.29 (0.15-0.57)**
25 - 36 0.29 (0.14-0.58)**
37 - 48 0.14 (0.07-0.27)**
49 - 60 0.13 (0.07-0.26)**
S. mansoni
No -
Yes 1.79 (1.07-3.0)*
P. falciparum
No -
Yes 1.69 (1.11-2.56)*
Stunting
No -
Yes 1.75 (1.03-2.96)*
Splenomegaly
No -
Yes 2.06 (1.51-5.09)**
*p<.05; **p<.01
OR: odds ratios
95% CI: 95% confidence interval
Egg count declines but reductions in morbidity markers

10. Table 5. Anaemia associated factors and corresponding multivariate adjusted
odds ratios at baseline
Associated Factor Adjusted OR (95% CI)
SIMI cohort
(n=570)
Anaemia
prevalence
68.8%
Age (months)
0 - 12 -
13 - 24 0.29 (0.15-0.57)**
25 - 36 0.29 (0.14-0.58)**
37 - 48 0.14 (0.07-0.27)**
49 - 60 0.13 (0.07-0.26)**
S. mansoni
No -
Yes 1.79 (1.07-3.0)*
P. falciparum
No -
Yes 1.69 (1.11-2.56)*
Stunting
No -
Yes 1.75 (1.03-2.96)*
Splenomegaly
No -
Yes 2.06 (1.51-5.09)**
*p<.05; **p<.01
OR: odds ratios
95% CI: 95% confidence interval
Egg count declines but reductions in morbidity markers

11. Where: transmission dependant selection
Biannual can be used at I and II
- What about recalcitrant areas first
morbidity control
Prevalence(%)
50.0 -
10.0 -
100.0 -
INSUFFICIENT
PROGRESS IN
SAC
2015 S. mansoni
Lake Albert setting

12. When: if intensification of treatment is needed - UGANDA
Runga school in 2003 & 2015
Combination diagnostics
1 2 4 5

13. When: if transmission control is needed - CAMEROON
• Need to treat those that slip through MDA net
and make PZQ available/reported throughout the year

14. How: MDA (?x2), MDA + selective treatment of DGs
PSAC: is needed but since no current MDA options then ?annual/?biannual treatment in EPI
SAC: simple 6-month repeat of MDA in SAC, with or without ALB/MEB
Adults: community annual MDA but regular access to PZQ in health centre (seek treatment)
Biannual could be used in either CONTROL and(or) ELIMINATION setting…
think about production/supply, equity of access, cost-effectiveness, compliance, resistance
Some points for discussion and further thought

15. Thank you – to many friends & colleagues – for stimulating discussions