LTC Russell E. Coleman, Ph.D. Director, Entomology Division Walter Reed Army Institute of Research What can Vector Diagnostics do for the Deployed Entomologist?

LTC Russell E. Coleman, Ph.D.Director, Entomology Division

Walter Reed Army Institute of Research

What can Vector Diagnostics do for the Deployed Entomologist?

Opinions, interpretations, conclusions, & recommendations are those of the author and are not

necessarily endorsed by the U.S. Army.

2007 DoD Pest Management Workshop 2

Agenda

• What are Vector Diagnostics?

• What do results tell us?

• Example where vector diagnostics were used operationally

• Concept of Operations

• Development, fielding and sustainment of vector diagnostics


Key Tasks of Deployed Entomologists

1. Surveillance (Collect arthropods)

2. Identification (Determine what’s there)

3.

RiskAssessment

RiskReduction

4. Personal Protective Measures

5. Vector Control

What are Vector Diagnostics?

Diagnostics (Test for pathogens)


What are Vector Diagnostics?

• Any method of determining if an arthropod is infected with a militarily-relevant pathogen.

• Examples:► Dissection/Visual Examination: Check midguts for oocysts or salivary glands for

sporozoites (Cheap, low-throughput, time-consuming, high level of training, good quality microscopes required)

► ELISA: Test head/thorax and abdomens for Plasmodium circumsporozoite protein (Medium cost, high-throughput, High-level of training, various equipment, cold-chain);

► Malaria VecTEST Assay: (Medium cost, medium-throughput, low level of training, simple, no cold-chain)

► Standard PCR: (Medium/High cost, medium-throughput, high level of training, complicated, cold-chain)

► Real-time PCR: (High cost, medium-throughput, high level of training, simpler, + cold-chain)


Manual Dissection of Mosquitoes

Malaria Dipstick Assay Real-time PCR in Iraq

Prototype Leishmania Assay


What do results tell us?

• Negative Results: Minimal information! Tells us pathogen was not present in samples tested; however, does not necessarily mean pathogen is not present in area. Issues: ► Sample size (100 mosquitoes tested versus 10,000 tested)► Limited collection sites (may have missed key sites)► Limited collection dates (a week or two later pathogen present)

• Positive Results: Much more useful! Tells us pathogen present, but not necessarily whether soldiers are at risk (incompetent vectors, non-man biters, etc.):


How can results be used?

• Negative Results: Not much use

• Positive Results: Extremely useful!!!► Identify high-risk areas;► Allow for prioritization of control/education efforts;► High impact when requesting support► Increases probability that CDR/1SG will enact PVNTMED recommendations;


Operational Use of Vector Diagnostics

• Leishmaniasis (Tallil Air-Base, Iraq) ► Base Occupied 22 Mar 03► First sand fly collected 7 Apr 03► First positive sand fly 22 Apr 04

• Immediately Implemented Prevention and Control Program• Immediately Implemented Education Program• Immediate High-Visibility with Senior Command• First human case not detected for >4 months

• Malaria (Tallil Air-Base, Iraq)► All troops on malaria chemoprophylaxis;► Vector surveillance revealed low numbers of anophelines (not sufficient to discontinue chemoprophylaxis);► Vector diagnostics revealed all anophelines uninfected (resulted in discontinuance of chemoprophylaxis);


Concept of Operations• Hand-Held Assays:

► User: PVNTMED Tech (91S), Entomologist, ESO► Unit: PVNTMED Det, BCT PVNTMED Section► Purpose: Screening Assay► U/I: 5/Ento Collecting Kit or “As Needed”► Reporting of Results: ??? (CHPPM, Command Surgeon/PVNTMED)► Issues: Cost to procure

• Real-Time PCR Assays: ► User: Microbiologist, Laboratory Technician (91K)► Unit: AML, FDPMU, AF BAT;► Purpose: Confirmatory Assay► U/I: JBAIDS/RAPID assigned to unit, assays procured as required► Reporting of Results: ??? (PVNTMED Units, Command Surgeon…)► Issues: Getting samples to unit


Status of Vector Diagnostics

• Hand-Held Assays:

► Malaria VecTEST Assay (Pf, PV-210, PV-247): Re-established, NSN recommendation, soon available thru VecTOR Test Systems;

► West Nile VecTEST Assay (WEE, WEE/SLE, WEE/SLE/EEE…): NSN, available thru Fisher Scientific;

► Leishmania VecTEST Assay: Under development (Phase II SBIR)

► Dengue VecTEST Assay: Ditto

► Rift Valley Fever virus VecTEST Assay: Ditto

► Ross River virus VecTEST Assay: Ditto

► Japanese Encephalitis VecTEST Assay: Ditto


Status of Vector Diagnostics

• Real-time PCR Assays:

► Leishmania (Leishmania universal, L. major-specific, visceral-specific; WRAIR and AFIOH)

► Dengue universal (AFIOH)

► USAMRIID virus assays (RVF, Dengue, JE….)

► Various other research-grade assay that have been published


Development, Sustainment & Fielding Issues

• Development: ► Hand-Held Assays: Only one company working on these. Funded through SBIR program► Real-time PCR Assays: Majority of work at USAMRIID. Need to investigate transition of assays onto JBAIDS platform

• Sustainment:► Hand-Held Assays: Commercial product with small market► Real-time PCR Assays: Once assays transitioned to JBAIDS, enter assays into CRP (Critical Reagents Repository)

• Fielding:► Hand-Held Assays: Cost, Basis of issue► Real-time PCR Assays: Validate need for vector assays with JBAIDS program


?Air Force Army Navy

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LTC Russell E. Coleman, Ph.D. Director, Entomology Division Walter Reed Army Institute of Research What can Vector Diagnostics do for the Deployed Entomologist?