# Management of ticks and Lyme disease in

protected natural areas
USGS Patuxent Wildlife Research Center Coastal Field Station, Woodward Hall – PLS University of Rhode Island Kingston, RI 02881 USA 

### Howard S. Ginsberg, Ph.D.Lyme disease

RMSF Other tick - borne WNV

Other mosquito - borne

Plague 

## Human cases of vector- borne diseases, United States, 2002

## Lyme disease

vector reservoirs pathogen

## Life cycle of Ixodes scapularis

adults larvae nymphs adults POPULATION 1 POPULATION 2 

### nymphs adults larvae

SPRING SUMMER FALL WINTER SPRING SUMMER FALL

hosts hosts 

### YEAR 1 YEAR 2

## Approaches to managing ticks and Lyme disease

- Self - protection precautions

- Habitat manipulation

- Manipulation of host populations



### - Biological control

- Pesticide applications

- broadcast



### - host - targeted

### Integrate techniques so as to efficiently lower

probability of exposure to pathogen Pe 

### = 1 – (1 – kv 

### ) n Pe = probability of being bitten by at least one infected vector kv = proportion of vectors infected with pathogen (=prevalence) n = number of vector bites 

# IPM for tick - borne diseases of humanskv =0.10 kv =0.01 kv =0.25 kv =0.5 

## Probability of exposure to pathogen

NUMBER OF TICK BITES PROBABILITY OF EXPOSUREfrom: Ginsberg. 1993. American Journal Of Epidemiology 138:65 - 73.kv =0.10 kv =0.01 kv =0.25 kv =0.5 

## Probability of exposure to pathogen

NUMBER OF TICK BITES PROBABILITY OF EXPOSURE

## Approaches to managing ticks and Lyme disease

- Self - protection precautions n Minimal effect

- Habitat manipulation n Substantial effect ( )

- Manipulation of host populations n and/or kv Substantial effect ( )

- Biological control n Nontarget effects ( - )

- Pesticide applications Nontarget effects ( - )

- broadcast n broad

- host- targeted kv narrow Management technique Lowers n or k v Environmental effects

## Habitat requirements of Ixodes scapularis nymphs

poor habitat good habitatADULTS PER SAMPLE 

### Habitat distribution of Ixodes scapularis

NYMPHS PER SAMPLE

### Environmental factors affecting nymphal distributionHabitat shifts from the larval to the nymphal stage, Fire Island, NY

From Ginsberg et al. 2004. Environ . Entomol .33:1266 - 1273.MEAN NO. TICKS PER SAMPLE 

### ** * * Nymphal Ixodes scapularis inside and outside of deer exclosures, Fire Island National Seashore, NY

From Ginsberg et al. 2004. Environ . Entomol. 33:1266 - 1273.

### Landscape design works at three levels

1) Landscape design affects tick population size

- likelihood of tick encounter

- transmission dynamics of pathogen 2) Landscape design affects host abundance

- reservoir competence of alternative host species

- diversity of host species 3) Landscape design affects human encounter with ticks

- probability of human exposure to pathogen

### Habitat requirements for Ixodes scapularis nymphs

• moist leaf litter 

### • typically with forest canopy cover • appropriate hosts present Landscape features that lower tick abundance/number of tick bites • dry at ground level • open forest canopy • appropriate hosts excluded (local? area - wide?) • people discouraged or excluded from tick habitat

### Lyme disease risk map – United States

Centers for Disease Control and Prevention

### Barriers – various functions Paths – separate people from tick habitat

## Useful references Bowman, AS & P Nuttall (eds.) 2008. Ticks: Biology, Disease and Control . Cambridge University Press, Cambridge, UK. Ginsberg, HS & KC Stafford, III. 2005. Management of ticks and tick - borne diseases, pp. 65 - 86 In Goodman, JL, DT Dennis, & DE Sonenshine (eds.) Tick- Borne Diseases of Humans . ASM Press, Washington, DC. Gray, JS, O Kahl, RS Lane, & G Stanek (eds.) 2002. Lyme Borreliosis, Biology, Epidemiology and Control . CABI Publishing, Wallingford, Oxon, UK. Mullen, G & L Durden (eds.) 2009. Medical and Veterinary Entomology , 2 nd ed., Academic Press, Elsevier Science, San Diego, CA. Stafford, KC, III. 2007. Tick Management Handbook , revised ed., The Connecticut Agricultural Experiment Station, New Haven, CT. (available online at: www.caes.state.ct.us - phone: (203) 974 - 8440)