By: Jean Francois Fesselet, MSFH

1
VECTOR CONTROL IN SLEEPING SICKNESS EMERGENCY
RESPONSE

• By Jean Francois Fesselet, MSF-H
• Based on Annick Lenglets field work.
• Presentation for the
• Interagency Environmental Health Forum
• 08-09 January 2004.

2
Sleeping sickness transmission cycle
3
Tse Tse fly

• Males and females bite
• Only young flies get infected
• Infected for life
• Lives up to 3 months
• Feeds every 1 to 3 days.

4
Treatment

• Current lab tests not 100 satisfying
• Side effects of drugs limiting adherence
• Resistance to some drugs (old drugs)
• Availability of drugs
• gt Rapid control with treatment only unlikely

5
Strategies for sleeping sickness control

• Passive screening, diagnostic and treatment
• Active screening, diagnostic and treatment
• Active screening, diagnostic, treatment and
  vector control

6
Prevalence determines strategy

• Low prevalence gt passive screening diagnostic
  treatment
• High prevalence gt active screening diagnostic
  treatment

7
Guinea, 1985-1987

• 3 different strategies
• Epicentre A 27.5. VC screening every 6 months
  diagnostic treatment
• Epicentre B 8.38. Screening every 6 months
  diagnostic treatment
• Periphery 3. Screening once a year, diagnostic
  treatment.

8
Added value of vector control

• Brings the prevalence down to zero quicker than
  with treatment only (6 months instead of 1 year
  or more)
• Keeps the prevalence down longer than with
  treatment only

9
Disadvantages of Vector Control

• Increases costs
• Increases burden on project

10
Vector Control in MSF-H

• Vector Control in Ibba, South Sudan Project,
  1999
• 2000 MSF-H left and project was not continued.
• gt was vector control at all possible?

11
Vector Control in MSF-H

• Feasibility study in September 2001 in Gamboma,
  Congo
• appropriate site to conduct Operational Research
• smoothly running medical activities
• relatively simple logistical access to areas of
  high sleeping sickness prevalence

12
Republic of Congo

• Country in several wars from 93 till 99
• Very limited health services
• Since 1990 dramatic resurgence of sleeping
  sickness
• Past experience with Vector Control in country

13
Operational Research

• Specific Objectives
• Reduce male and female fly populations by more
  than 90 in the human activity radius targeting
  transmission sites
• Reduce sleeping sickness transmission combining
  VC and medical activities six months or longer in
  five chosen villages comparing to 5 control
  villages
• Involve the communities in all aspects and stages
  of the intervention.

14
Study Area
15
Study Area
16
Traps and Screens
Screens
Pyramidal Trap
Biconical Trap

• 550mg AI impreg.
• interior capture bag
• produced locally
• 20 traps per village

• 90 mg AI impreg.
• produced locally
• 15 screens per village

• no impregnation
• only evaluation use
• produced locally

17
Fly Results

• Fly Numbers
• Age Grading

18
Fly Numbers
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Age Grading
20
Epidemiology Screening 2001 and 2002
2001
2002
Legend
21
Epidemiology Screening 2001 and 2002
Prevalence values in 2001 and 2002 and the
respective reduction in prevalence between these
two years.
22
Constraining Factors

• Villages control ? Vector Control villages not
  properly matched.
• Timing vector control activities started 2
  months into the dry season and several more
  months after medical activities.

23
Constraining Factors

• Barrier creation 5km barrier-zone not
  achieved
• Health Education started late in the Gamboma
  project.

24
Is Vector Control Feasible for MSF??

• YES!
• Easy to do (if security allows)
• Breaks faster the transmission cycle than with
  medical activities alone.
• Greater and longer lasting effects
• Now, clearly established steps to VC
  implementation (no logistical hurdles etc).

25
Recommendations

• Clear conditions should be set when initiating
  such a project
• high prevalence (higher than 1)
• Unstable situation
• Target time/space cluster village location (if
  possible) to build barrier, early in (long) dry
  season
• integrate medical, vector control and health
  education activities
• energy and resources into the maintenance of
  trap-helpers and/or village health workers.
• simplify traps maintenance and monitoring