david k. james, rehs alameda county environmental health - vector control october 20th, 2015

David K. James, REHSAlameda County Environmental Health - Vector Control

October 20th, 2015

Biology of the Human Bed Bug Cimex lectularius

SINCE THE MID 1990’S, BED BUGS HAVE BECOME MORE COMMON

Bed bugs tend to be associated with poorly maintained and poor sanitary conditions, however …..

Any house is a good habitat for bed bugs. (A place to shelter and a food source is all they need)

A place to stay And something to eat

SERVICE REQUESTS ACVCSD• Initially infestations found in high-end hotels in

New York, Las Vegas, San Francisco (late 1990s to early 2000s)

• Now spread throughout the community nationwide.

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 20140

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1 0 2 8 5 822 29

68

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179 179

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343

Request For ServiceBed Bugs

Bed bugs

# o

f R

FS

BED BUG BIOLOGYSOME IMPORTANT ASPECTS FOR CONTROL

Order: Hemiptera ( Sub-Order: Heteroptera) Family: Cimicidae (74 spp) Genus: Cimex Species: lectularius

Piercing and sucking mouth parts

Feeds exclusively on the blood of mammals (related species on birds).

Preferred host of C. lectularius is HUMANS – (Much preferred)

Control implications: Pesticides are NOT ingested

Hemiptera: True bugs

Reduviidae: Triatoma spp.:Chagas disease

Leaf-footed bugHarlequin bug Cotton strainers

OTHER INSECTS & MITES WITH HUMAN HOSTS

Scabies mite

Tropical rat mites

Bird mite

Chigger

FAMILY CIMICIDAE

This family includes the parasites of animals.These ecto-parasites feed on the blood of birds and mammals, including bats.Bed bugs are flattened dorso-ventrally. Front wings are always reduced to small pads.All species live away from the host animal except when feeding.

Bedbugs are flattened dorso-ventrally. Front wings are always reduced to small pads.

RELATED SPECIES ATTACKING MAN

BAT BUG, Cimex pilosellus (Horvath) Occasional household pest

SWALLOW BUG, Oeciacus vicarius May enter homes when swallow nests removed

POULTRY BUG, Haematosiphon inodorus Found in hot dry areas Can become severe poultry pest May invade homes

CIM

EX

LE

CT

UL

AR

IUS

(LIN

NA

EU

S)

CO

MM

ON

H

UM

AN

B

ED

B

UG

Feeds prim

arily on hum

ans but will attack

bats, chickens and other m

amm

als

Worldw

ide distribution

Ancestor probably bat

parasite that utilized “cave dw

elling human”

Earliest record c.1350

BC

in Egypt

BED BUG LIFE CYCLE

Ectoparasites

Five nymphal stages and adults

Obligated blood feeders with all stages

Not implicated as a disease vector

1. Short life cycle – 30-45 days (under optimal conditions)[ 75-80% RH; 83-90o F ]

2. Eggs resistant to pesticides and heat and can be laid (glued) anywhere.

3. Females can lay 1-5 eggs per day. Hatch in 7-10 days

4. Blood meal needed to molt and for egg laying.

Only 10% of bedbugs will be feeding on a particular night

5. Most harbor near host (70%) but not all

6. Live in cracks and crevices, difficult to locate. Prefer rough surfaces

7. Bite is painless, most people don’t react initially. Older people react less to the bite.

Population can grow quite large before resident is aware of the infestation

8. Can go without Feeding for some time:1.

1st instars most vulnerable (14-36 days)5th and adults least vulnerable (42- 143 days)

9. Nymphs & adults stop feeding at 56oF (13oC) Thermal death point is 112oF @ 7 hrs, 118F (ad) 123F (eggs) @ 0 min

NO tarsal pads

No pads to pick up

pesticide

Tarsal padsHouse fly

Walk with body off the ground

Can walk over pesticide treated

area without being affected

Typical feeding position

• Feed between 12 & 6 AM

• Feed for 2-15 mins. Multiple feeding sites

Engorged bedbug

Harborage site, a short walking distance to restaurant

Blood/fecal spots on pillow case

All stages micturate

male

female

TRAUMATIC INSEMINATIONREPRODUCTION

Unusual reproduction – extragenital.Male punctures body wall of female to inject spermatozoa into the spermalege.Spermatozoa migrates to female genital tract.No courtship - mate rapidly.Mating occurs away from host.Females may travel some distance to get away from males.

Copulating couple

Male paramere

Beak or rostrum

Cleft of copulatory pouch (female)

Cimex lectularis tends to cluster in cracks, preferring old harborages and places which smell of bed bugs.

Meta-thoracic scent apparatus Host Detection: (when unfed)

Temperature Attraction to oily skin secretion and CO2 involved.

PESTICIDE RESISTANCE

Resistance to pyrethroids among bed bugs has become a major problem.

A number of resistant populations have been identified on the West Coast. An increasing number of resistant bed bugs are being found especially in the East Coast

• Pyrethroids bind to a protein in nerves called voltage-gated sodium channel prevent it from closing, causing continuous nerve stimulation.

• Resistant bed bug populations have evolved by changing the size of the pore (gate), preventing the binding of the pyrethroid.

• Resistance-associated genes have been found in the integument (cuticle) of the bed bug which could reduce insecticide penetration and enhance detoxification before reaching the target sites.

David K. Jamesdavid.james@acgov.org510.567.6816

To Conclude

The more you know about Bed bugs…

The easier it is to control (kill) them.