Stephen L. Doggett
Senior Hospital Scientist
Department of Medical Entomology
Institute for Clinical Pathology & Medical Research,
Pathology West, Westmead Hospital, Westmead NSW 2145
Overview

Ticks: overview

Biology: lifecycle & ecology

Tick Management

Avoidance
Repellents
 Efficacy
 Human safety

Ticks

Worldwide – about 800 sp.
 Australia – 75 (~15 attack humans)
 2 groups – Soft & Hard ticks

Most important - Ixodes holocyclus
 Paralysis tick, scrub, bush, shell back
 Seed, grass (larval stage)
Adult
Female
Adult
Male
1mm
Nymph
Larva
Tick Life Cycle
Paralysis tick,
Ixodes holocyclus
Host Seeking
Behaviour
0.5m
3m
When are ticks active?

Most of the year

Survival dependant on humidity

Most active:
 Following rain
 Periods of high humidity

Larvae far more common than other stages
 High mortality in larval stage to nymph
Animal Hosts
Red-necked Wallaby
Norwegian Rat
Northern Brown Bandicoot
House Mouse
Bush Rat
Southern Brown Bandicoot
Magpie
Grasslands Melomys
Long-nosed Bandicoot
Australian Raven
Water Rat
Mountain Brushtail
Possum
Domestic Fowl
Crimson Rosella
Common Brushtail
Possum
Human
Pied Butcherbird
Brush-tailed Phascogale
Dog
Echidna
Koala
Cat
Common Dunnart
Swamp Wallaby
Pig
Feathertail Glider
Rabbit
Eastern Grey Kangaroo
Red-legged Pademelon
Black Rat
After Roberts (1970)
Main Host
Bandicoot
Tick Removal
MAKE SURE
YOU REMOVE
THE HEAD!!!
Tick Management

Cultural Control: Behaviour modification

Physical Control: Exclusion fencing

Biological Control
 Host removal
 Habitat modification

Chemical Control
 Habitat treatment
 Personal Protection
 Host treatment
Tick Control Methods
Control Method
Control Duration
Fire
Host Removal
Chemical Treatment
Personal Protection
Environmental Impact
Habitat Modification
Chemical Control

Advantages
Rapid control, 97% within 24 hours
 Cost effective
 Less environmental damage


Disadvantages
Not tick specific
 Relatively short term


Pyrethroids: Permethrin,
Betacyfluthrin, Bifenthrin
Cultural Control

Avoid ticky habitat

Avoid good ticky times

After rain, high humidity

Wear light coloured clothing

Check oneself regularly during & after

Tuck pants into socks, shirts into pants

Remove clothing, place into hot dryer

Use repellents/permethrin on clothing
Formulations
Gimmicks
APVMA

Australian Pesticides & Veterinary
Medicines Authority
(National Registration Authority: NRA)

For insecticides/repellents, assess:
 Human Toxicity
 Product Efficacy
 Environmental Impacts

Active

Approved use

Registered?

Directions
Repellent Actives
DEET (N,N-Diethyl-meta-toluamide)
 Picaridin
 Lemon Eucalyptus Oil (PMD)
 IR3535
 Citronella, melaleuca oil

“Natural”
“Organic”
=
“Safe” &
“Effective”
Repellent Efficacy

Mosquitoes

Fradin & Day, NEJM (2002)
Active
%
Protection Time
DEET
24%
302m
DEET
20%
234m
DEET
6.7%
112m
Citronella
10%
20m
Citronella
5%
14m
Citronella (WB)
25%
0.2m
Permethrin Impregnated Clothing

Permethrin = toxicant not a repellent

Two forms:
 DIY, ‘dip’ clothing
 Impregnated fabrics (IF)

Studies show:
 IF better protection than DIY
 IF more washes than DIY
 IF less environmental impacts
 Permethin better protection than repellents
 Widely used by armies
Permethrin Impregnated Clothing?
Registered





Equip
The Travel Doctor
Impregnation packs
10ml/4L H2O, soak 2m
Effective 6 months
Human Safety

Risk analysis
 What is worse: bites or repellents?

DEET first registered, 1957
 Billions of uses
 Recommended by WHO & CDC
 Only product recommended by CDC
 US EPA: adverse reactions 1:100million

EPA: “permethrin factory-treated clothing is unlikely to
pose any significant acute or chronic hazard to people”

“Naturals” are a greater risk to human health!!!
Read & heed the label!
WE WANT
YOUR
TICKS!