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Why Would I Want To Do

Larval Surveillance Anyway?

Or, if I am going to be playing in water, I

would really rather be fishing!

Rosmarie Kelly, PhD MPH

Public Health Entomologist

Georgia Department of Public Health

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Larval Surveillance!

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1. What is surveillance?2. Why is surveillance important?

3. What are the various types of surveillance?

4. How does mosquito control use adult surveillance

data?5. If we are doing adult surveillance, why is larval

surveillance needed?

6. Do I really need to ID?

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So, what am I going to talk about?

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What is Mosquito Surveillance?

Mosquito surveillance is trappingmosquitoes in a way that they can besystematically evaluated.

Surveillance is used to define the natureand extent of the mosquito problem and to

gauge daily mosquito control operations. It provides a basis for:

developing control efforts

evaluating the effectiveness of controloperations

determining the potential for transmission ofmosquito-borne diseases

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FOR SURVEILLANCE TO BE USEFUL, IT IS

IMPORTANT TO KEEP GOOD RECORDS

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Orthopodomyia signifera(This mosquito has never been

documented to bite people, but it is

known to take avian blood. )

Ochlerotatus atlanticus(The females bite mammals readily and severely.)

If possible, ID!

Basing your control efforts onunidentified specimen counts and/or

complaints can potentially waste

manpower, funds, time, and pesticide!

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crane fly no mouthparts

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BENEFITS OF IDENTIFICATION

You will know the problem species atany given time

Control methods or products can bechanged to deal with different species

Pre- and post-control collections canverify the effectiveness of yourprogram

You can establish larval surveillance

and control efforts based onknowledge of the target species

Your over-all program will be muchmore successful and cost effective

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Knowing what mosquito species are present and

where they are breeding helps with creating an economically and

environmentally responsible mosquito control program.

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To have effective control - you must target theproblem species

To target - you must identify the problemspecies

To identify - you must conduct surveillance andcollect specimens

To conduct surveillance - you must know whereto collect (at complaint sites, previously known sites, or areas whereyou suspect mosquitoes will be a problem)

Its All About Effective Control

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Types of Mosquito Surveillance

Adult surveillance

Monitoring complaints

Landing counts

Trapping (with or without ID)

Larval surveillance

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FOR ADULT CONTROL, THE SPECIES NAME

PROVIDES INFORMATION ABOUT:

Importance (vector or nuisance)

Type of larval habitats

Biting periodicity

Normal blood hosts

Normal flight range

Traps that are effective

Resting sites

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Some Common

Mosquito SpeciesLarval Habitat Biting Time Flight Range

Aedes albopictus

artificial

containers &

tree holes

Day100 - 300

yards

Culex quinquefasciatus

ground pools,

catch basins,artificial

containers

Crepuscular,Night

1/4 - 1/2 mile

Aedes vexans

Flooded grassy

and woodedareas

Day,

Crepuscular,

Night 5 - 8 miles

Coquillettidia

perturbansCattail marshes

Crepuscular,

Night 1 - 5 miles

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Using Adult Surveillance Data

Provides data for local

risk assessment

Assists in makingmosquito control decisions

Saves money by fine-tuning control efforts

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THE SPECIES NAME ALSO PROVIDES

INFORMATION FOR LARVAL CONTROL:

The type of larval habitat utilized permanent water

temporary water

artificial or natural containers salt marshes

The correct control method and pesticides most

effective for the targeted larvae

The peak time of the year for larvae of yourtarget species

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So Why Do Larval Surveillance?

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Larvicides can be used to controlmosquitoes in the aquatic stage

before they become biting adults.

This type of control generally hasthe least effect on non-target

species and the environment.

Larviciding

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Larviciding

While mosquitoes will

potentially take advantage

of any standing water, not

all water contains larvae.

The only way to determine

if larvicide should be

applied to a body of wateris to do larval surveillance.

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Benefits of Larval Surveillance

Larval surveillance is used to: identify new breeding habitats

check suspect habitats

monitor mosquito populations

Larval surveillance also provides an

indication of:

the number of mosquitoes in a

breeding habitat

whether they are in a growth stage

that can be controlled with larvicides

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Breeding Index

Larval density is almost always expressed as numbers of larvae andpupae per dip, but density is most useful if expressed in terms ofpopulation size.

John Belkin (Mosquito News, 1954) developed a simple index fordetermining larval densities that may be useful:

BI = TLP/ND x BP BI = the breeding index

TLP = the total number of larvae and pupae taken

ND = the number of dips

BP = the number of breeding places

A "breeding place" is defined as each separate microhabitat or stationwithin a site from which at least one positive dips is obtained.

BI = 25/50*5 TLP = 25 total larvae and pupae; ND = 50 total dips

BI = 2.5 BP = 5 sites dipped

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Larval Identification

Finding larvae is just the first step

If the mosquito is not a nuisance species or avector of disease, it doesnt need to be controlled

In order to know that, you must identify thelarvae

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In 1995, an increase in numbers ofCulexspp found

in CDC light traps led to a search for possible reasonsfor this change.

One factor that stood out was that the increased

number ofCulexspp. seemed to be associated with

bodies of water where recently introduced water

chestnut was abundant.

The Lakes District of the Charles River in Newton

and Waltham, Massachusetts was chosen as a

survey site, and mosquito larvae were sampled from

areas of either high water chestnut or high water lily

densities in 1995 and 1996.

It was found that mosquito larvae were abundant in

areas of high water chestnut density and infrequent

or missing in all other areas (graph).

Larvae were collected in 1996 and identified to

species (graph).

All were found to be Uranotaenia sapphirina.

WATER CHESTNUT AND CULEXMOSQUITOES(A True Story)

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females are not known to bite humans

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Tools for Larval Surveillance

Dipper

Boots

Whirl Packs, Pipettes, Baster

Administrative Support

Time to do the job

Defense against the naysayers

Funding, as though it were any other program

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Larval Program Goals

Begin surveillance and subsequent controlin/near populated areas

Ask the questions:

Does this system produce?

Is it appropriate to treat it?

What method of treatment is indicated?

Let the program build on itself

Set reasonable goals for the program

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Container Breeders - Peridomestic Mosquitoes

Control container breeders by controllingcontainers - solid waste reduction Public Education

Brochures

Speak at schools & gatherings

Neighborhood cleanup programs

Legally

Existing ordinances

Work with code enforcement and the locallegal system

Make connections with the local healthdepartment, especially Environmental Health

Start with

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Work on Developing

A mosquito habitat inventory - a permanent collection ofdescriptions for all habitats. Organize breeding sites into some kind of system -

route book

map system

index cards A larval surveillance system - describes the abundance of

mosquito larvae at each site. The information can be used to determine optimal times for use

of larval control measures, including chemicals, biologicals,draining, or impounding.

It also can be used to help forecast the need and timing foradult mosquito control and to help assess the effectiveness ofboth chemical and biological control measures.

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Some Useful Resources

http://www-rci.rutgers.edu/~insects/larvsurv.htm

http://www-rci.rutgers.edu/~insects/dipping.htm

http://mosquito.ifas.ufl.edu/Mosquito_Surveillance.htm

http://msdh.ms.gov/msdhsite/_static/resources/800.pdf

http://www.malariajournal.com/content/pdf/1475-2875-7-20.pdf

http://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdf

http://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdf(Belkin, 1954)

http://www.gamosquito.org/mosquito.htm

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http://www-rci.rutgers.edu/~insects/larvsurv.htmhttp://www-rci.rutgers.edu/~insects/dipping.htmhttp://mosquito.ifas.ufl.edu/Mosquito_Surveillance.htmhttp://msdh.ms.gov/msdhsite/_static/resources/800.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://www.gamosquito.org/mosquito.htmhttp://www.gamosquito.org/mosquito.htmhttp://www.gamosquito.org/mosquito.htmhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://archive.org/download/cbarchive_114364_simplelarvalandadultmosquitoin1954/MN_V14_N3_P127-131.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/supplementary/1475-2875-7-20-s2.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://www.malariajournal.com/content/pdf/1475-2875-7-20.pdfhttp://msdh.ms.gov/msdhsite/_static/resources/800.pdfhttp://mosquito.ifas.ufl.edu/Mosquito_Surveillance.htmhttp://www-rci.rutgers.edu/~insects/dipping.htmhttp://www-rci.rutgers.edu/~insects/dipping.htmhttp://www-rci.rutgers.edu/~insects/dipping.htmhttp://www-rci.rutgers.edu/~insects/larvsurv.htmhttp://www-rci.rutgers.edu/~insects/larvsurv.htmhttp://www-rci.rutgers.edu/~insects/larvsurv.htm

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Any Questions?

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