Mosquito-borne virus prevention and control: a global perspective

Transcription

1 Mosquito-borne virus prevention and control: a global perspective Chikungunya 2017, Sapienza Universita di Roma 10 November 2017 Erika Garcia Mathematical Epidemiologist World Health Organization Geneva, Switzerland garciaer@who.int

2 Objective To provide a summary of the global strategies for prevention and control of mosquito-borne diseases

3 27 November 2017 Outline 1. Current situation 2. Surveillance and early detection, lab, clinical management 3. Vector control strategy 4. Challenges 5. Next steps

4 27 November Current Situation - Emergence & Re-emergence - Dengue causing extensive human disease - Chikungunya - Geographic expansion and changes in pattern of illness /2016 Zika virus outbreak was unexpected - YF Outbreaks in areas previously not at risk (urban)

5 Dengue Burden estimation Malaria 1 Dengue WHO RECENT 2 Population at risk 3.2 billion 2.5 billion 4 billion Endemic countries 96 > Infections /year 214 million 50 million million Severe Cases 3 million 2.1 million Deaths/ year 438,000 20,000 40,000 1) Global Malaria Report ) and Brady et.al. PLoS Negl Trop Dis 2012; 6: e1760

6 Trends in cases reported to WHO EMR AMR WPR SEAR

7 Spread of Aedes-borne Disease Estimated dengue age-standardized cases from increased nearly 450%

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9 27 November 2017 Americas

10 27 November 2017 Chikungunya and Dengue, Pakistan Outbreaks Karachi Started Nov 2016 and continues. Health authorities estimate the total number of patients to be more than The National Institutes of Health, Pakistan, and Armed Forces Institute of Pathology, Pakistan, confirmed cases through qualitative RT-PCR. Dengue in Peshawar (Jul to Sept) also detected CHIKV. 50,000 cases Chikungunya virus was found circulating in rodents in Pakistan as early as A few patients with chikungunya were also reported in Lahore during the 2011 dengue outbreak.

11 Yellow fever, Angola, 2016 Dec '15 Oct '16, 4347 susp cases, 377 deaths Spread to DRC, 2987 cases and 121 deaths Btwn 18 Mar - 4 Apr 2016, a total of 9 imported cases of YF from Angola were reported by NFP China. Unvaccinated workers. Source: MoH, China Meteorological Admnistration Location No. of cases Population (million) March Lo-Hi Temp ( C) Past reports of Dengue Beijing to 11 - Fuzhou to Shanghai to 13 -

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14 27 November 2017 The context

15 27 November Surveillance and early detection - Early detection of Aedesborne outbreaks - Integrated surveillance (humans, animals, vectors) - At-risk populations i.e, pregnant women, elderly - Utilize existing systems, i.e., AFP surveillance, Congenital Rubella Surveillance, Sentinel

16 27 November 2017 Laboratory - Laboratory techniques: RT-PCR, ELISA or IF, PRNT - Collection of patient samples: urine, saliva not just sera - Challenges for Zika, et al: expertise about flaviviruses since interpretation is complex. No WHO prequalified test

17 27 November 2017 Clinical management All arboviral diseases transmitted by Ae. spp. (DENV, CHIKV, and ZIKV) currently have no specific treatment. But clinical management for each is very important Studies needed to see the severity of CHIKV No vaccine

18 above all, the spread of Zika, the resurgence of dengue, and the emerging threat of Chikungunya are the price being paid for a massive policy failure that dropped the ball on mosquito control in the 1970s. Margaret Chan Former Director-General, World Health Organization Opening Address at World Health Assembly 69th session May 2016

19 3. Global Vector Control Response REDUCE THE BURDEN AND THREAT OF VECTOR-BORNE DISEASES THAT AFFECT HUMANS ENABLING FACTORS Country leadership Advocacy, resource mobilization and partner coordination Regulatory, policy and normative support Reduce incidence by 60% Reduce mortality by 75% By 2030

20 Aedes control is linked to many SDGs Each goal is important in itself And they are all connected

21 Vector Control Objectives To reduce human-vector contact To reduce longevity and abundance of disease vectors To reduce vector breeding sites, where and when possible

22 Involvement of Communities Vector control methods applied in a community will depend on the local situation and preferences of the population. Suitable methods should be: Effective Affordable Simple to understand and easy to apply Acceptable and compatible with local customs, attitudes and beliefs Safe to the user and the environment. Methods used in one place may not work in another place Social mobilization to eliminate breeding sites (targeting mothers, educating children through games), health promoters going to door to door for visits educating how to prevent disease, removing water containers.

23 Larval Control Chemical control Organophosphates Pyrethroids Spinosad Insect Growth Regulators Biological control Fishes Copepods Biocides Bacillus thuringiensis var israelensis Environmental Control

24 Conditions for space spraying Precise location to be sprayed Distribution of case house(s) The case history [when is the first case (index case), movement pattern of cases, probable source of infection] Type of vector (Aedes aegypti vs Aedes albopictus or both) Major breeding sites Adequate trained supervisors Number of trained spray people available for mobilization Availability of protective cloth and accessories Health information and communication back up

25 Entomological indicators disease incidence The actual entomological indicators are all based on densities: Larvae (HI, BI, LI), Pupae (PI) and Adults (HI). Larvae and Pupae densities are far away from the transmission. These indicators are linked to climatic and social conditions, but cannot be related to diseases incidence. 27 November 2017 Adults females densities are more close to transmission, however, the fluctuations of the females abundances is not always directly related to transmission since factors such as duration of life (survival) and immunological status of human population can have more significance.?

26 27 November 2017 Preparedness plans National preparedness plans in collaboration with local levels Identify human resources needed, training required Entomol/Epi surveillance integrated Multi sectoral approach Increasing awareness of physicians (malaria case earlier this year) Development of Regional plan

27 27 November Challenges Rapid development of insecticide resistance in mosquitoes Educating the public of reduction of sources of standing water Major commercial investment is needed for vaccine development for Zika and Chikungunya. Difficulty in predicting future outbreaks making it difficult to do efficacy trials and future markets. Improved surveillance and Point-of-care diagnostics

28 27 November Next Steps Conceptual framework is needed for Aedes-borne diseases Change from disease specific programs to comprehensive approach End points differ, specific treatments and vaccines. Upstream is same. More efficient than developing specific antiviral drugs, vaccines Further research on: animal reservoirs, natural history of disease, global burden Innovative methods, tools for vector control Development of laboratory diagnostics urgently needed

29 27 November 2017 Acknowledgements Sergio Yactayo IHM/WHO Kyohei Nishino IHM/WHO Florence Fouque TDR/WHO Raman Velayudhan NTD/WHO

30 Thank you!