Managing Neglected Tropical Disease Control: Complexity, Uncertainty, and Governance

Transcription

1 Managing Neglected Tropical Disease Control: Complexity, Uncertainty, and Governance ITM Colloquium 2014: The Human Factor Social Sciences in Global Health Research, Antwerp, Nov 2014 Edwin Michael University of Notre Dame

2 Current Global Parasite Control Approaches: assumes a traditional public-economy theory of public good provision, ie fundamentally state-centered goals (preferences) and solutions are well known and established Problem solving/goal seeking orientation Linear causality: reliance on simple cause and effect Science and technology have the required answers ignores or takes little account of socio-ecological complexity o parasitism as a dynamic human-natural interacting system o adaptive system dynamics

3 MAJOR QUESTION? Is eradication of the major NTDs a simple tame problem where both the problem and solutions are well known? Or do they represent complex persistent societal problems that require new modes of governance/management?

4 I. Ecological Complexity: Parasite Extinction Thresholds and achievement of Elimination Targets Extinction thresholds serve as important management targets for determining attainment of parasite eradication Arise and occur as functions of dynamical ecological processes that govern persistence, resilience and extinction of parasite systems Analysis of mathematical models of parasite transmission permits detection and quantification of the existence, nature, and magnitude of eradication thresholds

5 Model analysis: complexity - multiple steady states and endpoints/thresholds in filariasis/onchocerciasis 2 Breakpoints function of: Max Breakpoint Wb (MDA) 0 uptake functions in vectors mating probabilities aggregation immunity 1 3 (VC)

6 EMERGENCE PROPERTIES OF COMPLEX DISEASE SYSTEMS

7 Complex dynamics: impact of initial conditions on endpoints a) increasing aggegration from i to iii decreases breakpoints b) decreasing immunity from I to iii decreases breakpoints c) decreases in worm fecundity from I to ii decreases breakpoints Cx An

8 Estimating Endpoints/Breakpoints by Fitting to Field Data (LF)

9 Frequency distributions of endpoints in Culex (a) and Anopheline (b) LF communities: endpoints vary within (uncertainty/stochasticity) and locally between sites! (a) (b)

10 Uncertainty and choice of elimination thjresholds: 50%, 75% and 95% breakpoint probability thresholds

11 Complex Dynamics: Duration of MDA required to eliminate transmission will vary widely between-communities and for thresholds with different probabilities of extinction The intervention results for 5 selected sites (above) are shown for the 95%-EP transmission threshold. Huge variability between sites in the required rounds of annual MDA as a function of drug coverage. The heat-plot (right) shows the mean rounds of annual MDA at 60%, 80% & 100% drug coverages for the 50%, 75% and 95%-EP thresholds for all 18 LF communities. Anopheline communities Culicine communities

12 mf II. Complexity- Evidence for Critical Slowing Down in LF? impact of embedded feedback loops which begin to operate in system crisis situations 1. Convergence rates to equilibrium states 2. Sticking of system when nearing elimination thresholds age (years)

13 III. Complexity- Malaria and LF co-infection 1: Maps showing the prevalence (%) of (A) malaria and (B) LF 2 : Co-infection map showing where the prevalence of both infections are above various thresholds.

14 III. Complexity- Schematic model of malaria-lf co-infection dynamics A complex and highly interconnected disease system. Slater et al. (2013), PLoS Comp. Biol.

15 III. Complexity- Unintended consequences of mass treatment for eliminating LF in a malaria-lf co-endemic community A. The prevalence (%) of LF under different drug coverages of 60% - 90%. B. As mass treatment reduces LF prevalence in the community below its elimination threshold (shown as dotted line in (A)), the prevalence of [untreated] malaria cases goes up and finally settles at a new endemic level higher than its endemicity level in the LF-malaria co-endemic case.

16 LF infection prevalence Mf prevalence (%) IV. Complexity The socio-ecology of LF transmission Rich Poor 0 Mambrui-1 Mambrui-2 Philippines Number of studies Fig. 1: Spatial variation in LF infection at the household level in Masaika village, Tanzania Fig. 2: Prevalence of LF is disproportionately aggregated in the poor (p<0.05). Data for Mambrui from Wijers and Kinyanjui (1978), Ann Trop Med Parasitol 71: ; and for Philippines from Grove et al. (1978), Bull WHO 56: high k value low k value Transmission Spread Fig. 3: Estimation of the aggregation parameter k 0 from the observed microfilariae (mf) count data indicates a highly overdispersed/heterogeneous distribution and transmission of LF-mf in individuals of Kirare in Tanzania. Fig. 4: Transmission of LF in highly heterogeneous versus homogeneous transmission settings. Elimination threshold for LF prevalence can vanish under heterogeneous/aggregated transmission conditions (solid line) compared to homogenous transmission settings (dashed line).

17 FEATURES OF LF TRANSMISSION AS A COMPLEX MESSY PROBLEM? IN PUBLIC POLICY Open, interacts with surroundings and highly sensitive to initial conditions Consists of components linked via mutual interactions Contains positive and negative feedback loops that amplify or dampen system response Behavior highly non-linear and heterogeneous with emergent properties Has various system attractors and thus states Can give rise to unintended negative external responses, eg. impacts on other diseases, LF-malaria, schistomiasis-hpv, worm-allergies Knowledge constrained by partiality, plurality and provisionality Finally, since problem of transmission is socially structured, any resolution will require social change as well as innovation in parasite governance structures : denotes a messy problem!

18 Finally, management from outside a societal system may not be effective: structures, actors, and practices adapt and anticipate in such a manner that these should also be directed from inside KEY QUESTION: HOW DO WE GOVERN OR RESOLVE COMPLEX MESSY PROBLEM? Accepting/embracing ecology-in-contexts and system dynamics uncertainty Opening up/joint framing of policy problems and options by all stakeholders, including the local community: - multi-domain, multi-level, multi-actor approach Indicates there may be multiple paths to achieving parasite control in different social settings Management at the system level is important: spillovers, unintended consequences can only be recognized at system level and so needs transdisciplinary approaches of enquiry Link content and process: process mangt alone not sufficient, investigation of how local social organizations work at different levels (ind to group) to solve or achieve outcomes is essential for creating feasible means of mngt Objectives need to be flexible and adjustable at the system level: need for reflexivity and social learning - keeping options open Creating space for agents to innovate : role of experimentation important

19 CURRENT GOVERNANCE STRUCTURE AND INSTITUTIONS IN GLOBAL NTD CONTROL: A TOP-DOWN COMMAND AND CONTROL APPROACH DIRECTED FROM OUTSIDE? Hierarchical with epistemic networks at top level: closed problem framing and solutions Top-down deterministic, equilibrium and blue-print based technicist approach Knowledge flow primarily one directional State simply to deliver prescriptive top-down standardized solutions largely derived externally Discourages experimentation Little engagement with local society perspectives

20 JAPANESE EXAMPLE OF AN INTEGRATED MULTI-ACTOR, MULTI- DOMAIN, MULTI-TIERED APPROACH TO NTD CONTROL? School-based deworming Teachers used for deworming and health education Linked to family planning and nutritional programs Community-based health promotion which encouraged community participation focus on influencing societal change in risk behaviours via joint searching and learning and experimenting? Program led by private sector, JAPC, local governments and Japanese Govt via proclamation of School Health Law- pluralistic network approaches, Govt acting interactively to activate and stimulate networks? Special effects of war?

21 IMPORTANCE, IMPLICATIONS AND NEED FOR SOCIAL SCIENCE STUDIES IN NTD CONTROL Application of social theories of societal complexity provides an important tool for understanding how best to link and address system and management complexities jointly Will be key for investigating how best to align preferences of citizens and the efficient provision of control, including uncovering the means for making choices that give citizens a voice in collective decision making Can help unpack the politics of knowledge production to guide development of effective alternative institutional solutions in generating knowledge and ensuring its diffusion Are central to explicate the paradigms, ontologies/epistemologies and assumptions that underpin current and proposed approaches to problem setting and solutions, allowing investigating of how biases in thinking and power relations can close down options for effective parasite control Are central for developing new modes of governance that considers parasite control as a socio-ecological process in which co-evolution between structures, actors and practices occur, which critically require to be taken into account when developing sustainable interventions