Control of disease vectors
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Consortium for the Barcode of Life Regional Meeting Nairobi, Kenya 18-19 October 2006. Control of Disease Vectors. Dr Yvonne-Marie Linton Natural History Museum, London. Correct species identification is critical for effective control of insect-borne pathogens and agricultural pests.

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Control of Disease Vectors

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Control of disease vectors

Consortium for the Barcode of Life Regional Meeting

Nairobi, Kenya 18-19 October 2006

Control of Disease Vectors

Dr Yvonne-Marie Linton

Natural History Museum, London


Control of disease vectors

Correct species identification is critical foreffective control of insect-borne pathogens and agricultural pests


Uses of dna barcodes

Uses of DNA Barcodes

As a diagnostic tool:

  • for identifying regulated species:

    • disease vectors, agricultural pests, invasive species

    • protected species, CITES listed, trade-sensitive

  • for general scientific research

    • ecological studies, inventories

      As a “Triage” tool

  • for flagging potential new species (undescribed and cryptic)

    To assist in taxonomic research


New dna barcoding schemes

New DNA Barcoding Schemes

Mosquitoes (c. 3500 spp) – vectors of malaria, filariasis, dengue, yellow fever, JE, West Nile virus etc

Fruit flies (Tephritids) (c. 3000 spp) – economically devastating pests of fruit crops worldwide

Both have been accepted by CBOL as ‘demonstrator’ projects


Control of disease vectors

MBI inceptive meeting, NHM, London 21-22 Nov 2005


Can dna barcoding work in mosquitoes

Can DNA barcoding work in mosquitoes?

Can a short region of DNA (720bp of COI) really enable us to identify all known species?

Can it help identify unknown species?


Why barcode mosquitoes

Why barcode mosquitoes?

  • Relatively small but diverse group

  • Relatively well known

  • Actively researched worldwide

  • Huge potential impact on parasitic and arboviral disease control


Overcoming the global taxonomic impediment

Overcoming the global taxonomic impediment

DNA characters are easier to obtain and compare, making the discovery of new species more rapid

BUT

sequence data is effectively useless unless meshed with a strong taxonomic framework based on morphology

Integrated systematic studies are “the new taxonomy”


Control of disease vectors

An. (C.) christyi

An. (N.) oswaldoi

atropos

sacharovi

persiensis

98

martinius GB

Palaearctic

atroparvus

94

100

95

labranchiae GB

messeae

79

64

daciae

67

maculipennis

70

melanoon

96

beklemishevi

quadrimaculatus

75

maverlius

66

smaragdinus

95

inundatus

87

95

100

Nearctic

diluvialis

occidentalis

95

freeborni

hermsi

92

earlei

87

ITS2 phylogeny Maculipennis Group (745 seqs)(GB GenBank)

New species identified on basis of DNA data and formally described using integrated description


Control of disease vectors

Annularis Group

1000

600

500

400

300

200

96

ITS2

100

100

96

nivipes

philippinensis

annularis

99

Wide geographical sampling reveals new species

0.02

annularis India*

annularis Viet/Korea/Laos/Camb

annularis Philippines*

philippinensis Vietnam/Laos

nivipes Vietnam/Cambodia/Laos

jamesi Vietnam

maculatus Vietnam


Control of disease vectors

Voucher specimens


Outcome of the mbi inceptive meeting

Outcome of the MBI inceptive meeting

MBI objectives: To generate DNA barcodes for at least 5 specimens of each species of 80% of the World Culicidae within two years


Major obstacles to objectives

Major obstacles to objectives

  • How many Culicid species are there?

  • Where will we find them?

  • Where would the specimens come from?

    • Frozen DNA collections?

    • Field collected samples?

    • Museum specimens?

We realised that for the project to be a success in such a short time frame, museum specimens would have to play a major role


To meet our objectives

To meet our objectives

  • A pilot study to assess the feasibility of getting usable DNA from Museum specimens must be undertaken - If success rate was higher than 50% we could go ahead with the project!

  • An up-to-date taxon list was needed!

  • Species distributions needed to be established


Smithsonian institution usa may 11 12 2006

Smithsonian Institution, USAMay 11-12 2006

  • Update meeting of 5 members of the MBI steering committee to assess success of pilot study


Museum specimens from 2000

CPV1-1 An. philippinensis

Luksang Kampong, Preah Vihear Province, Cambodia. Human Bait. Linton et al., 2004

Sigma

Qiagen

GenBank AF546338 mtDNA COI

GenBank AJ674540 nDNA ITS2

500 bp

Museum specimens from 2000

COI: LCO1490F/HCO1490R


Control of disease vectors

A. LCO1490F/HCO2198R

B. LCO1490F/C1J1718MODR

An. gambiae – 1938

An. minimus – 1998

An. gambiae – 1936

St. aegypti – 1973

St. aegypti – 1954

St. aegypti – 1916

C. quinquefasciatus -1969

Neg. extraction

An. gambiae – 2001

Neg. PCR

Archive mosquitoes (QIAmp micro kit, QIAgen)


Optimal dna extraction from museum specimens

Optimal DNA extraction from Museum specimens

Minimum of 12-24hrs in shaking incubator @ 55oC

100μl GB

10μl Prot K

2 min

QIAgen Blood kit and magnetic bead DNA transfer

QIAgen Biosprint, 50μl


Priority order of sequencing

Priority order of sequencing?

  • Field collected samples less than 10 years old (silica gel or pinned)

  • Mosquitoes stored individually in >80% ETOH and less than 10 years old

  • Mosquito specimens from pinned collections >10 years old

  • Slide mounted larvae/pupae

    Specimens from as wide a geographical range as possible will be used


Culicidae species list

Culicidae species list

  • 3,449 formally recognised species as at July 1 2006

  • Quantitative counts of museum holdings

  • 2930/3449 in 9 collections

  • 85% of all currently known taxa are available to MBI


Zoogeographic distribution of culicidae genera approx number of species per region

Zoogeographic Distribution of CulicidaeGenera (approx number of species) per region

14 (200)

14 (190)

23 (880)

18 (560)

24 (820)

20 (520)


Control of disease vectors

MBI

Co-ordinators:

Y. Linton & R. Lane

NHM

Co-ordinators: R. Harbach (morph) & Y. Linton (mol)

SMITHSONIAN

Co-ordinators: R. Wilkerson (morph) & D. Foley (mol)

ITM

W. Van Bortel

UND

N. Besansky

India

Co-ordinator:

P. Kumar

SE Asia

Co-ordinator:

P. Somboon

Africa

Co-ordinator:

M. Coetzee

Latin America

Co-ordinators:

M. A. Sallum & M. Quinones

Australasia

Co-ordinator: D. Foley

World mosquito workers


Mbi strategy summary

MBI strategy summary

  • Primarily reliant on museum specimens but fresh is better!

  • To actively include global members of the mosquito community as collaborators

  • Donations of specimens will be acknowledged in the BOLD database

  • All specimens will be identified and voucher specimens stored where possible

  • Access to the data will be immediate and free.


Current status of mbi

Current status of MBI

  • We have a updated species list

  • We have knowledge of species distribution

  • We can get good quality sequenceable DNA from museum specimens

  • We have tested the utility of the barcoding primers across many Culicidae genera

  • We have access to 85% of all the known taxa

  • We need your help!

    BUT WE ARE READY TO GO!


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