Dengue proposal

1. Dengue proposal Considerations for design of the phase II follow up

2. Background • DPSEEA was used to introduce the notion of urban ecosystem health. • The framework was applied to chronic aspect of urban conditions in Cayo Hueso. • Participatory approaches were used to define key indicators. • The findings: • Measurable improvements in subjective indicators. • Inconclusive change in more objective indicators.

3. Follow on research for dengue • Reapply the phase I methods again. • Elaborate on DPSEEA introducing: • the importance of context, • ecosystem processes and their interactions • Broader ecosystem health/integrity perspective. • Refine the indicators: • learning why there is a gap between the subjective and objective outcomes. • Create a new decision-making and evaluation framework emphasizing learning objectives and adaptive management: • Dengue is an episodic risk in Cuba. Monitoring and intervention for such problems are not the same as those of a chronic issue such as housing.

4. Lessons from Phase I • Relative importance of exogenous factors. • Challenges in attributing effects to intervention without a “control” population. • …

5. Opportunity in Phase II

6. The bigger picture

7. Why does an overallframework matter? • Monitoring is like our eyes • Decision-making is like our brain • We cannot look everywhere • We cannot think of everything • We need to think about costs and benefits of every monitoring and intervention action. • We need to find the efficient and effective set of observations (monitoring) that allow appropriate actions (campaigns).

8. Issues in control of epidemics • Monitoring is less than perfect • e.g. infected are asymptomatic but have viremia • Symptoms of potential infection may go mal-reported (know 5 day bed-rest could lead to over reporting (if compensated) and under reported (if time substitution is unavailable to the patient). • Intervention efficacy is less than perfect: • depends on social acceptance, • depends on suitability to ecosystem (e.g. “closed” buildings), • depends on being timely, which is itself reliant on frequency of monitoring and speed of interpretation. • Direct and intended benefits of monitoring depend on the efficacy of interventions that could be triggered by it. • Imperfect monitoring and interventions erodes social acceptance and trust.

9. Three dimensions to evaluation The challenge of sustainability in the absence of a signal • Effects: • direct and intended • indirect and ancillary • Benefits and costs: • cases of dengue and DHF • other health effects • improved living conditions, … • Measures: • Objective, subjective • Information flow and feedback to decision making The opportunity for sustainability through indirect benefits

10. An Ideal Policy • Has community support. • Has positive impacts. • Is monitored and enforced effectively. • Has self-righting properties. • Has free-drivers. • Meets more than one objective.

11. Take the case of dengue in Cuba:We need to identify the policy goal, approach & constraints • Goal • prevent dengue • Actions: • Reduce breeding sites for A. aegypti • Eradicate mosquito population • Isolate potential infected people from healthy • Means: • Monitoring, interpretation and dissemination of information, • Decision-making processes • Constraints: • The time of field workers • The time of households • The cost of fumigation (money and incidental health impacts) • The implications of forced bed-rest for feverish people • Loss of public interest for participation

12. The overall framework Ecology The scientific input Society Goals and values The ecologically possible The socially preferred Whatoutcome to encourage and when How Intervention Monitoring Governance

13. Design alternatives when to act? what to do? Find best system monitor what? monitor how? Mosquito habitat Mosquito density Disease locally Disease regionally Weakly active network until trigger Adaptive hotspot monitoring • [1 » a] • [2 » a+b] • [3 » a+b+c] • [2+3 » a+b+b] • [4 » 1 » a+b] • … Destroy habitat Destroy mosquito Change behaviour …

14. How should the monitoring/intervention evolve at different levels of force of infection? The iterative cycles of monitoring and intervention. E.g.: • The first 90% can be controlled through identification and elimination of the 1st levels risk factors. • The next 90% through identification of 2nd level risk factors and interventions • The next 90% through identification of 3rd level risk factors and interventions. • The next 90% … The rule for when to stop is determined by the whole human-vector-virus ecology. For a disease that is hard to transmit, we can stop at the level of the first risk factors. For a disease that is easily transmitted we need to go to understanding and controlling smaller and smaller risk factors.

15. Mosquito feeds & acquires virus Mosquito refeeds & transmits virus Extrinsic incubation period(~9 days) Intrinsic incubation period (~7 days) Illness Illness A.aegypti inecosystem Transmission of Dengue Virusby Aedes aegypti Viremia Viremia 0 5 8 12 16 20 24 28 Days Infectedhuman inecosystem Human #1 Human #2

16. Illness A.aegypti inecosystem Fumigation kills mosquitoes Transmission of Dengue Virusby Aedes aegypti Mosquito feeds & acquires virus Mosquito refeeds & transmits virus Viremia Viremia Viremia 0 5 8 12 16 20 24 28 Days Illness Infectedhuman inecosystem Human #1 Human #2

17. Illness A.aegypti inecosystem Transmission of Dengue Virusby Aedes aegypti Breeding site elimination Mosquito feeds & acquires virus Mosquito refeeds & transmits virus Viremia Viremia Viremia 0 5 8 12 16 20 24 28 Days Illness Infectedhuman inecosystem Human #1 Human #2

18. Illness A.aegypti inecosystem Transmission of Dengue Virusby Aedes aegypti Mosquito feeds & acquires virus Mosquito refeeds & transmits virus Forced bedrest isolates viremia from vector Viremia Viremia Viremia 0 5 8 12 16 20 24 28 Days Illness Infectedhuman inecosystem Human #1 Human #2

19. Research Ideas from UBC partners • Retrospective: A full evaluation (costs and benefits, intended and unintended) of the monitoring-intervention program. • What can be learned about dengue ecology because of the extra-ordinary setting? • A retrospective of health and environmental impacts of the control campaign in 2002. • Prospective: How should the monitoring/intervention evolve at different risks of epidemic? (refinement of methodology given Cuba’s special situation) • What are the pre-requisites for introducing self reinforcing and self-adjusting elements to the process?

20. Outcomes, Indicators & Interventions (to be evaluated)

21. Costs High cost May be too late for prevention epidemic Loss of privacy Benefits Screening for other diseases & behavioural change C&B of Interventions:monitoring blood samples • Weakness • Could change behaviour in seeking medical help • Strength • Least ambiguous test of dengue • Prerequisite to level of concern about DHF

22. Costs Continuous effort High labour input Benefits Cleaner environment C&B of Interventions:destruction of habitat • Weakness • Some households will not be able to comply. • As the vector is not eradicated but pressed for habitat it will change its behaviour • Strength • Could contribute to community spirit if organized as a social event.

23. Costs Loss of work Familiar discord More babies? Benefits More babies? Good to have a rest C&B of Interventions:quarantine • Weakness • Hosts have viremia long before they show symptoms. • Non-compliance • Could change behaviour in seeking medical help • Strength • It may provide spatially specific information for concentration of effort.

24. Costs Needs coordination of episodic effort & opportunity cost of labour and material input Contamination of environment Loss of ecosystem integrity Human health effects Benefits Destruction of mosquitoes C&B of Interventions:fumigation & spraying • Weakness • Closed houses. • Impatient home owners. • Poor public relations. • Does not kill larvae • Strength • Fast deployment • Politically visible • Triggers behavioural change

25. Costs High investment costs Only part of the solution Benefits Eliminates major habitats at home Reduced water-borne epidemics Better hygiene Saves time Reduces injury C&B of Interventions:reliable domestic water supply • Weakness • A long lead time • Strength • Strong public support • Will be easier to maintain

26. What aspects of the ecosystem-health approach are more readily adopted, why? • Does the approach have value if partially adopted? • Spatial and functional organization challenges? • What critical aspects are missing and why? • Does possibility of formal risk assessment, cost and benefit estimation, … approaches impact adoption patterns? • They did not resonate to the notion of cost. • How is “value” of information get translated into something of similar implication here? • What would be the features of a self-righting approach?

27. Need to identify goal, approach & constraints • Goal • prevent dengue • Actions: • Reduce breeding sites for A. aegypti • Eradicate mosquito population • Isolate potential infected people from healthy • Means: • Monitoring, interpretation and dissemination of information, • Decision-making processes • Constraints: • The time of field workers • The time of households • The cost of fumigation (money and incidental health impacts) • The implications of forced bed-rest for feverish people • Loss of public interest for participation