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Transcript of Facilitating Dengue Vector Surveillance for Disease ... Almatkyzy.pdf · PDF...

  • Facilitating Dengue Vector Surveillance for Disease Control: A pilot study

    Gulaiim Almatkyzy, M.S., John P. Grieco, Ph.D., Theeraphap Chareonviriyaphap, Ph.D., Sunny Shah, Ph.D., Nicole L. Achee, Ph.D.

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  • 2

    What would you say is the deadliest animal on Earth?

  • 3

  • Global Burden of Dengue

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    Endemic in >100 countries; 390 million infections, 96 million clinical cases annually

    Sources: 1. World Health Organization. (2017). Dengue and Severe Dengue. Retrieved from http://www.who.int/mediacentre/factsheets/fs117/en/2. HealthMap. (2018). Dengue Alerts for Past three months. Retrieved from http://www.healthmap.org/dengue/en/

  • Background: Dengue Virus

    Mosquito-borne viral infection

    Confirmed serotypes: DENV1-4 (DENV-5 is emerging)

    Range of disease -asymptomatic to flu-like symptoms and severe, fatal disease

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    Female Ae. aegypti mosquito in the process of acquiring a blood meal from her human host . Source: Centers for Disease Control and Prevention

    Source: Mustafa, M. S., Rasotgi, V., Jain, S., & Gupta, V. (2015). Discovery of fifth serotype of dengue virus (DENV-5): A new public health dilemma in dengue control. Medical Journal Armed Forces India, 71(1), 67-70.

  • Dengue Vector Control Strategies

    6Source: Achee ,N.L., Gould, F, Perkins, T.A., Reiner, R.C. Jr, Morrison, A.C., Ritchie, S.A., et al. (2015) A Critical Assessment of Vector Control for Dengue Prevention. PLoS NeglTrop Dis 9(5): e0003655. https://doi.org/10.1371/journal.pntd.0003655

  • Diagnostic Limitations

    PCR

    Expensive

    Time consuming

    Specialized laboratory

    ELISA

    Cross-reactivity

    Seroprevelance only

    PRNT

    Expensive

    Time consuming

    Specialized laboratory

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    Primary dengue infection with timing of diagnostic tests . Source: Tropical Regional Services, Queensland Health

    Source: CDC. (2017). Laboratory Guidance and Diagnostic Testing. Retrieved from https://www.cdc.gov/dengue/clinicallab/laboratory.html

  • VecTOR dipstick

    Immunochromatographic wicking dipstick assay

    Works by antigen-antibody sandwich principle

    Developed by VecTOR Test Systems

    8Source: Wanja, et al., (2014). Immuno-chromatographic wicking assay for the rapid detection of dengue viral antigens in mosquitoes (Diptera: culicidae). Journal of Medical Entomology, 51(1), 220-225.

    Testing VecTOR dipstick assay. Source: Personal Archive

  • Study Purpose

    Goal

    Improve dengue vector surveillance system at local level

    Objective

    Evaluate a rapid diagnostic tool to detect DENV in mosquitoes

    Aims

    Quantify the specificity and sensitivity of the VecTOR dipstick assay to detect DENV in field-collected mosquitoes and control samples

    Assess the acceptability of the VecTOR distick assay among laboratory personnel via questionnaire

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  • Study Sites

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    Nakhon Pathom Province,Sam Phran District

    Bangkok Metropolis,Sai Mai district

    Source: Maps of World. (2016). Thailand. Retrieved from https://www.mapsofworld.com/thailand/provinces/nakhon-pathom-map.html

  • Field Activities

    Household selection

    Indoor collection(A)

    Purposive sampling

    Prokopack aspirator

    Outdoor collection (B)

    Simple Random Sampling

    BG-Sentinel traps

    Mosquito storage

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    Mosquito collection. Source: Personal Archive

  • Laboratory Test Work Flow

    50 dipsticks

    30 (pooled mosquitoes)

    30 samples

    4 (preliminary research)

    16 (training)

    8 positive control

    8 negative control

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  • DENV Detection Summary

    1306 total field-collected mosquitoes (61 households)

    Site of collection Culex and Anopheles Aedes Female

    Sai Mai district 57 7

    Sam Phran district 947 260

    KU campus 21 14

    Total 1025 281

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    Out of 281 pooled mosquitoes into 30 tubes

    Sample Type PCR VecTOR dipstick

    DENV+ (n=1) n=1 N=0

    DENV- (n=29) n=29 N=29

    DENV+ control samples (n=8) n=8 N=4

    DENV- control samples (n=8) n=8 N=8

    56.3% Cohens Kappa agreement between PCR and VecTOR dipstick

  • Questionnaire

    Distributed to laboratory personnel

    15 closed-ended questions

    Three sections (5 questions each)

    Ease-of-use

    Practicality

    Integration

    Six-point Likert rating scale

    0 (not applicable)

    1 (strongly disagree)

    5 (strongly agree)

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    VecTOR dipstick assay training. Source: Personal Archive

  • 4.2 4.2 44.6 4.6 4.8 4.4

    54.4 4.47

    42.8 3

    3.83.2

    3.8

    3.2

    4

    1.8

    3.29

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    2.6 2.8

    3.6

    3

    3.4

    3.2

    4

    2.2

    3.2

    user 1 user 2 user 3 user 4 user 5 user 6 user 7 user 8 user 9 average

    Section Scores(VecTOR Dipstick)

    Ease of Use Practicality Integration

    Questionnaire Summary

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    4.47 3.29 3.20

  • Summary

    Goal of dengue surveillance systems is to control spread of virus within human populations

    Dengue diagnostic tests are an essential component of disease surveillance and management systems - need for rapid, inexpensive, point-of-care tools with high sensitivity and specificity

    VecTOR dipstick assay has potential as a user-friendly tool where capacity for PCR testing is limited: High specificity (100%) Fair sensitivity (44%) Considered easy to use

    Practicality and integration were questionable

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  • Recommendations and Next Steps

    Train other lab personnel and community members

    Test in other regions (field-collected mosquitoes) - other flaviviruses and arboviruses to assess cross-reactivity

    Larger sample size (for sensitivity and specificity)

    Further research on practicality of the assay

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  • Acknowledgements Supervisor

    Dr. Nicole L. Achee

    In-Country Supervisor

    Dr. Theeraphap Chareonviriyaphap

    Committee members:

    Dr. Sunny Shah

    Dr. John Grieco

    Special thanks:

    Dr. Wunrada Surat

    Ms. Flora Klacsmann

    Ms. Amonrat Panthawong

    Ms. Thikhumporn Sittivicharpinyo

    Laboratory assistants:

    Students from Department of Entomology, KasetsartUniversity

    Students from Department of Genetics, KasetsartUniversity

    Field assistants:

    The Department of Environment, Saimai District, Bangkok Metropolis

    The Department of Fishery Science, KasetsartUniversity

    The Head Office of Sam Pran District, Nakhon PathomProvince

    All community workers of Sam Pran District and Saimai District

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  • Thank You for Your Attention!

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