regarding vector control in the Americas Anubis Vega Ra Institut - - PowerPoint PPT Presentation

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Sep 12, 2022 409 likes •937 views

Current gaps and challenges regarding vector control in the Americas Anubis Vega Ra Institut Pasteur of Guadeloupe MEETING OF THE INSTITUT PASTEUR INTERNATIONAL NETWORK (RIIP) AMERICAN REGION (Sao Paulo, 3-5 July, 2019) Vector-borne

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Current gaps and challenges regarding vector control in the Americas

Anubis Vega Rúa Institut Pasteur of Guadeloupe

MEETING OF THE INSTITUT PASTEUR INTERNATIONAL NETWORK (RIIP) – AMERICAN REGION

(Sao Paulo, 3-5 July, 2019)

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WHO(2017)

 17% of the estimated global burden of infectious diseases (> 700 000 deaths/year) 80% of the world's population is at risk of one or more vector-borne disease.

Vector-borne diseases (VBD): a major and global problem

Malaria, Lymphatic filariasis, dengue, leishmaniasis, japanese encephalitis, yellow fever, Chagas disease, human African trypanosomiasis and onchocerciasis

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Chagas disease

  • 21 countries
  • 65 million at risk
  • 6-8 million cases
  • 19 countries
  • 64,000 cases/year
  • 7% fatality rate

Leishmaniasis

  • Endemic in 4 countries
  • 12.6 million at risk

Lymphatic filariasis Malaria

  • 21 countries
  • 145 million at risk
  • 469,000cases (2012)

Yellow fever

Since 2016:

  • 5 countries reporting
  • ~2210 cases
  • ~760 deaths
  • >43 countries/territories
  • > 1 million cases

Chikungunya

  • 500 million at risk
  • 2.3 million cases (2013)
  • Hyperendemic

Dengue West Nile

USA (1999-2011):

  • ~4 millions cases
  • 1261 deaths

Zika virus

  • 48 countries/territories
  • > 750 000 cases

Vector-borne diseases in the Americas

Randolph & Rogers Nat Rev Microbiol (2010), PAHO(2019), WHO (2019), Espinal et al Rev Panam Salud Publica (2019)

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Chagas disease

  • 21 countries
  • 65 million at risk
  • 6-8 million cases
  • 19 countries
  • 64,000 cases/year
  • 7% fatality rate

Leishmaniasis

  • Endemic in 4 countries
  • 12.6 million at risk

Lymphatic filariasis Malaria

  • 21 countries
  • 145 million at risk
  • 469,000cases (2012)

Yellow fever

Since 2016:

  • 5 countries reporting
  • ~2210 cases
  • ~760 deaths
  • >43 countries/territories
  • > 1 million cases

Chikungunya

  • 500 million at risk
  • 2.3 million cases (2013)
  • Hyperendemic

Dengue West Nile

USA (1999-2011):

  • ~4 millions cases
  • 1261 deaths

Zika virus

  • 48 countries/territories
  • > 750 000 cases

Vector-borne diseases in the Americas

Randolph & Rogers Nat Rev Microbiol (2010), PAHO(2019), WHO (2019), Espinal et al Rev Panam Salud Publica (2019)

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The common point: the vector

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The common point: the vector

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Vector Control

William Crawford Gorgas Rationale: optimal use of resources for vector control. Overcome the challenges experienced with single-intervention approaches Efficacy Cost-effectiveness Ecological soundness Sustainability

WHO (2019), Vega-Rúa & Okeh (2019)

Integrated Vector Management (IVM)

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The structure of an IVM programme

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Examples of major successes achieved through vector control

Global Vector Control Response 2017–2030, WHO, (2017)

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Examples of major successes achieved through vector control

Global Vector Control Response 2017–2030, WHO, (2017)

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Contemporary increase of certain VBDs in the Americas

DENV Suspected cases Deaths caused by dengue

PAHO(2019)

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Challenges for IVM are greater today

Commercial/touristic air travel network ZIKV spread by air travel network

Gardner et al Plos Neg Trop Dis (2018)

Urbanization-Population growth

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Global trade

Carvalho et al Mem Inst Osw Cruz (2018)

Colonization of the Americas by

  • Ae. albopictus

Challenges for IVM are greater today

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Climate change

Escobar et al. Sci Rep (2016)

Potential distribution of vectors under current and future climate scenarios in Ecuador

Challenges for IVM are greater today

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Contemporary context increases the cost of IVM

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Contemporary context increases the cost of IVM

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Physical vector control: the oldest method

  • Mechanical elimination of breeding-sites

(source reduction)

  • Improvement of water supply and water-storage

systems

  • Waste management
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Housing Improvement Program for Chagas Disease Control

Anti-Vectorial housing: alternative for simultaneous VBD reduction

Housing [CO2] Temperature Vector house entry Humidity

Gambia: Well-fitted doors reduced An. gambiae house entry by 96%

Jatta et al. Lancet Planet Health (2018) Velleda dos Santos et al. Rev Soc Bras Med Trop(2016)

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Published and grey literature between Jan 1, 1980, and Nov 30, 2015 (updated on April 2, 2017)

Horstick & Runge-Ranzinger Lancet Inf Dis (2017)

Anti-Vectorial housing : gaps and challenges

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Anti-Vectorial housing : gaps and challenges

Horstick & Runge-Ranzinger Lancet Inf Dis (2017)

  • Few trials with appropriate efficacy assessment

GAP GAP Published and grey literature between Jan 1, 1980, and Nov 30, 2015 (updated on April 2, 2017)

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Horstick & Runge-Ranzinger Lancet Inf Dis (2017)

Increase the number of trials-combination with other vector control methods Standardization of the efficiency assessments Strong Community involvement Political and economical support Costly Large-scale implementation difficult Impacts simultaneously several vectors

Anti-Vectorial housing : gaps and challenges

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Chemical vector control methods: history and limits

Lack of specificity Negative effects on the environment/human health Resistance 2002 1965 1980’s XVIIe

Jousset, 1981

… 2013-2015

Quirin et al, 2004 Leparc-Goffart et al, 2014 Sautet, 1951 Nicolas et al, 2003

2016

1951: DDT 1969: Malathion & Temephos 1986: Deltamethrin 2009 & 2010: Temephos & Malathion Interdiction

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Multiple insecticide resistance in Ae. aegypti from Guadeloupe

  • Ae. aegypti resistance levels

Goindin et al. J Inf Dis Pov (2017)

Resistance: RR50 > 1 or KRR50 > 2

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Insecticide resistance is widespread in the Caribbean

CARPHA IVM Toolkit (2017)

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Resistance index (LC50) Adult mortality (%) Moyes et al. Plos Neg Trop Dis (2017)

The frequency of resistance to deltamethrin in Ae. aegypti, 2006–2015. The level of Ae. aegypti resistance to temephos, 2006–2015 Reference strain: Rockefeller susceptible strain

Insecticide resistance is widespread also in the Americas

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Insecticide resistance mechanisms in the Americas

Vézilier et al. Evol Applic (2012) , Moyes et al. Plos Neg Trop Dis (2017)

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Distribution of Ae. aegypti and Ae. albopictus ion the Americas

Kraemer et al. eLIFE (2015)

  • Ae. aegypti
  • Ae. albopictus
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Moyes et al. Plos Neg Trop Dis (2017)

Locations of bioassay data for the organophosphates and pyrethroids 2006 to 2015

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Moyes et al. Plos Neg Trop Dis (2017)

GAP GAP

Insecticide resistance poorly studied for Ae. albopictus

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  • Was the strategy we used for chemical vector control appropriate?

Which have been the results?

  • Did we collect all the needed data regarding vector populations before

the interventions?

  • Do we know which strategies have worked the best and where?
  • Did we monitor the populations to see if adaptations or modifications
  • f the strategies are needed?
  • Do we know how resistance evolved or may evolve?

What have we learned?

GAP GAP

Major questions we should ask:

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Challenges of chemical vector control methods in the Caribbean

Different legislations Different vector control strategies GAP GAP

  • Legislation not adapted to local needs
  • Lack of standardized resistance

assessment and surveillance

  • “Isolation”- Information sharing

(i.e. good practices, feedback)  Transfer of competence for capacity building  Networks (i.e. WIN)

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Insecticide resistance can modify vector competence and behavior

Insecticide resistance Behavior Vector competence Susceptible Resistant

Alout et al. Plos One (2013)

IVM strategies should evolve along with their vectors

Stanczyk et al. Sci Rep (2019) Carrasco et al Curr Op Ins Cont (2019)

  • Activity (early or late biting)
  • Increase of biting events outdoors
  • Differential perception of human odors
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Biological vector control methods targeting immature vector stages

Larvicides and Oviposition deterrents Predators of immature stages

Benelli et al. Insects (2016)

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Larvicides and Oviposition deterrents Predators of immature stages .Low remanence .Resistance .Large breeding-sites .Limited information

Benelli et al. Insects (2016)

.>80 species .Specificity? .Nanomosquitocides characterization? GAP GAP

Biological vector control methods: pros, cons and knowledge gaps

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Larvicides and Oviposition deterrents Predators of immature stages .Used in 60 countries .Small breeding-sites .Mass-rearing .Vietnam (2003-2000)! . Mosquito habitats suitability

Benelli et al. Insects (2016)

Biological vector control methods: pros, cons and knowledge gaps Specificity?

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Predators of immature stages

Benelli et al. Insects (2016)

Cryptic breeding-sites?

Larvicides and Oviposition deterrents

Biological vector control methods: pros, cons and knowledge gaps

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Benelli et al. Insects (2016)

Releasing “modified insects”

Scholte et al. Acta Trop (2007), Knols et al. Future Microbiol (2010), Benelli et al. Insects (2016)

Entomopathogenic fungi . Natural variations of viability, infectivity, and persistence of fungal spores in field populations . Delivery methods for increased specificity and large-scale application Different mosquito lethal toxins Less selective pressure for resistance Resistance evolution slower than resistance to chemical insecticides GAP GAP « One Health »

Biological vector control methods: pros, cons and knowledge gaps

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Releasing “modified insects”

Adapted from Flores & O’Neill Nat Rev Microbiol (2018)

Biological vector control methods: pros, cons and knowledge gaps

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Releasing “modified insects”

Adapted from Flores & O’Neill Nat Rev Microbiol (2018)

Mass-rearing Legislation (GMO)

Biological vector control methods: pros, cons and knowledge gaps

Monitoring and efficiency assessment Cost

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Behavioral Knowledge: A Tool to Enhance Mosquito Control Programs

Mating success of modified mosquitoes Behavioural Knowledge

Generate high quality mass-released mosquitoes

VS “Modified” mosquitoes Wild-type mosquitoes

Mass-rearing

GAP GAP

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To sum up…

Punctual successes in the past Challenges for IVM are greater today Insecticide resistance Behavior, Competence

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To sum up…

 Knowledge  Major gaps identified

Insecticide resistance

  • Fill research gaps (i.e. vector behavior)
  • Harmonization of vector control methods

Punctual successes in the past Challenges for IVM are greater today Behavior, Competence

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To sum up…

 Knowledge  Major gaps identified

Insecticide resistance

  • Fill research gaps (i.e. vector behavior)
  • Harmonization of vector control methods
  • Standardization of efficacy measures and

monitoring (strategy adaptation)

  • Information sharing

Behavior, Competence Punctual successes in the past Challenges for IVM are greater today

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To sum up…

 Knowledge  Major gaps identified

Insecticide resistance

  • Fill research gaps (i.e. vector behavior)
  • Harmonization of vector control methods
  • Standardization of efficacy measures and

monitoring (strategy adaptation)

  • Information sharing
  • Communication and multisectorial partnerships

Behavior, Competence Punctual successes in the past Challenges for IVM are greater today

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Global Vector Control Response Framework

Global Vector Control Response 2017–2030, WHO, (2017)

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Thank you for your attention! Agradecimentos para sua atenção!

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Gene drive approaches for vector control

Flores & O’Neill Nat Rev Microbiol (2018)

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Insecticides and behavior

Carrasco et al Curr Op Ins Cont (2019)

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Walter et al. Nature (2011) Whole females Legs

Evaluation of alternative vector control strategies: pathogen-resistance

DENV ZIKV

Carneiro Druta et al. Cell Host & Microbe (2016)

Non- infectious viral RNA

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Velleda dos Santos et al. Rev Soc Bras Med Trop(2016)

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