Transcript Mossies in Cyberspace: The NSW Arbovirus Surveillance
Stephen L. Doggett
Senior Hospital Scientist Department of Medical Entomology Institute for Clinical Pathology & Medical Research, Westmead Hospital, Westmead NSW 2145
Overview
Ticks – introduction
Biology/ecology/lifecycle
Management
Avoidance
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)
Tick Samples to DME
1988-2013: 671 specimens
Amblyomma: 3.7%
Aponomma: 0.3%
Haemaphysalis: 1.8%
Rhipicephalus: 1.3%
Ixodes: 93%
Ixodes holocyclus:
(98%) Adults: 37%, Nymph: 26%, Larvae: 37%
Adult Female Adult Male Nymph 1mm 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
Red-necked Wallaby House Mouse Magpie Australian Raven Domestic Fowl Human Dog Cat Pig Eastern Grey Kangaroo
Animal Hosts
Norwegian Rat Bush Rat Grasslands Melomys Water Rat Crimson Rosella Pied Butcherbird Echidna Common Dunnart Feathertail Glider Red-legged Pademelon
After Roberts (1970)
Northern Brown Bandicoot Southern Brown Bandicoot Long-nosed Bandicoot Mountain Brushtail Possum Common Brushtail Possum Brush-tailed Phascogale Koala Swamp Wallaby Rabbit Black Rat
Main Host Bandicoot
Tick Removal MAKE SURE YOU REMOVE THE HEAD!!!
Tick Management
Cultural Control:
Behaviour modification
Physical Control:
Exclusion fencing
Biological Control
Parasites/pathogens/predators Host removal
Habitat modification
Chemical Control
Repellents
Habitat treatment
Host treatment
Tick Control Methods
Control Method
Habitat Modification Fire Host Removal Chemical Treatment Personal Protection
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)
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?
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
”
Read & heed the label!
Host Exclusion Fencing
Habitat Modification
Reduce overhanging foliage
Clearing brush/bushes
Removal of leaf litter/mulch
Maintain lawns <15cm
Cementing
Inc. sunlight to ground, dec. humidity
Achieves most prolonged level of control
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
Bifenthrin
Pyrethroid
Toxic to lower vertebrates
Strongly binds to the soil
reduced contamination risk
Recommended by WHO for mosquito c.
BUT DOES IT WORK?
Two formulations
: Emulsifiable Concentration, Granular
Bifenthrin - Formulations
Granular
(Bithor, Brigade, Vigilanti)
Can be used against all stages Directions for use:
“Applications should be made in the spring to control larvae and nymphs that reside in the soil and leaf litter…”
Application
: Hand, fertilizer spreaders, backpack, aerial