Ticks with “black legs” and the Ticks with “black legs” and the d fd f d ffd ffdiscovery of discovery of Ixodes affinis Ixodes affinis in in 

North CarolinaNorth CarolinaNorth CarolinaNorth Carolina

Bruce A. Harrison PhDBruce A. Harrison PhDPublic Health Pest ManagementPublic Health Pest Management

WinstonWinston‐‐Salem, NCSalem, NC

Acknowledgments Walker Rayburn Jr.,  Perquimans CountyWalker Rayburn Jr.,  Perquimans County PHPM (Marcee Toliver, Barry Engber, Parker Whitt, NolanPHPM (Marcee Toliver, Barry Engber, Parker Whitt, Nolan PHPM (Marcee Toliver, Barry Engber, Parker Whitt, Nolan PHPM (Marcee Toliver, Barry Engber, Parker Whitt, Nolan 

Newton)Newton) Gene Powell, RaleighGene Powell, Raleigh Lance Durden, Georgia Southern University, StatesboroLance Durden, Georgia Southern University, Statesboro Richard Robins, Armed Forces Pest Management Board, Richard Robins, Armed Forces Pest Management Board, 

Washington DCWashington DCWashington, DCWashington, DC Brian Prendergast, U.S. Navy, Camp LejeuneBrian Prendergast, U.S. Navy, Camp Lejeune Rick Hickman, Brunswick CountyRick Hickman, Brunswick County Rick Hickman, Brunswick CountyRick Hickman, Brunswick County Jeff Brown, Brunswick CountyJeff Brown, Brunswick County Ricardo Maggi, NCSU Vet. School, RaleighRicardo Maggi, NCSU Vet. School, Raleigh Joe Piesman, CDC, Fort Collins, COJoe Piesman, CDC, Fort Collins, CO

The “Blacklegged tick” (previously called the “Deer tick”) or Ixodes scapularis, is the tick species confirmed as the

vector of Lyme disease spirochetes to humans in the eastern United States.eastern United States.

Lone Star tick nymphLone Star tick nymphBlacklegged tick nymphBlacklegged tick nymph

Lone Star tick nymphLone Star tick nymph

Not this one!This one!This one!

H th t l tH th t l t th i fth i fHowever, there are at least However, there are at least sevenseven other species of other species of IxodesIxodes in NC that havein NC that have “black legs” and most “black legs” and most of these do not transmit the spirochete thatof these do not transmit the spirochete thatof these do not transmit the spirochete that of these do not transmit the spirochete that causes Lyme disease in humans.causes Lyme disease in humans.

Also, there are Also, there are twotwo additional species of additional species of IxodesIxodesthat have light brown legs or banded legs.that have light brown legs or banded legs.

You cannot identify these ticks to species based on You cannot identify these ticks to species based on “black legs” Other more obscure“black legs” Other more obscureblack legs . Other more obscure black legs . Other more obscure morphological structures must be used that are morphological structures must be used that are difficult to see.difficult to see.difficult to see. difficult to see.

Ticks in NC with “black legs” and their Ticks in NC with “black legs” and their known hostsknown hostsow os sow os s

Ix. affinis Ix. affinis –– 15 mammals and 1 bird species15 mammals and 1 bird species

Ix. Ix. angustusangustus –– rodents and their predators (rodents and their predators (humanshumans))

Ix. dentatusIx. dentatus –– rabbits, their predators and birds (rabbits, their predators and birds (humanshumans)) Ix. dentatus Ix. dentatus rabbits, their predators and birds (rabbits, their predators and birds (humanshumans))

Ix. Ix. marximarxi –– squirrels, chipmunks, and their predators squirrels, chipmunks, and their predators

Ix. muris Ix. muris –– mice, rats, and birds (mice, rats, and birds (humans?humans?))

Ix. scapularis Ix. scapularis –– 41 41 mammal, mammal, 57 57 bird bird and and 11 reptile 11 reptile species (species (humanshumans))

Ix. Ix. texanustexanus –– raccoons, opossums, and rabbits (raccoons, opossums, and rabbits (humanshumans))te a uste a us accoo s, opossu s, a d abb ts (accoo s, opossu s, a d abb ts ( u a su a s))

Ix. Ix. woodiwoodi –– woodratswoodrats, predators, and birds (, predators, and birds (humanshumans) )

The life cycle for all of these species is basically the same but there are distinct biological differencessame, but there are distinct biological differences

Habitats Habitats usually match that of the primary host species usually match that of the primary host species tili d b th i t t d d lt Altili d b th i t t d d lt Alutilized by the immature stages and adults. Also utilized by the immature stages and adults. Also

birds can transport them to abnormal areas.birds can transport them to abnormal areas.

HostsHosts can be highly variable as some tick species are verycan be highly variable as some tick species are very Hosts Hosts can be highly variable, as some tick species are very can be highly variable, as some tick species are very specific in selecting their hosts, while others are specific in selecting their hosts, while others are generalists. generalists.

Distribution Distribution is also associated with the primary hosts, but is also associated with the primary hosts, but also determined by latitude, elevation, temperature, also determined by latitude, elevation, temperature, rainfall, humidity, vegetation type, etc.rainfall, humidity, vegetation type, etc., y, g yp ,, y, g yp ,

PhenologyPhenology (seasonality)(seasonality) of the life stages is variable. Some of the life stages is variable. Some species have the immature stages during coolspecies have the immature stages during cool--cold cold months, while others including the Blackmonths, while others including the Black--legged tick legged tick have the immatures during the warm months. have the immatures during the warm months.

Tick life cycle

Ticks collected by PHPM since Oct. 2008

31,108 total specimens

24,882 Am. americanum (Lone Star tick)

1,050 D. variabilis (American dog tick)

3,108 Ix. scapularis (Blacklegged tick)

853 Ix. affinis (no common name)

1,215 other species

The 2008 Collection of Ix. affinis in NCWhere: Gates Co.

When: April 2008When: April 2008

Who: Walker Rayburn

Explanation: This tick was not correctly identified until April 2009. Later, we found an earlier publishedan earlier published record of one specimen from a deer in Hyde County inin Hyde County in 1987

Ixodes affinis: Basic Information•• Originally a CentralOriginally a Central--South American speciesSouth American species

Fi t f d i Fl id i 1953 d t G i dFi t f d i Fl id i 1953 d t G i d•• First found in Florida in 1953, spread to Georgia and First found in Florida in 1953, spread to Georgia and South Carolina, and finally identified in NC in 2009South Carolina, and finally identified in NC in 2009

•• Easily misidentified asEasily misidentified as Ixodes scapularisIxodes scapularis, because they, because theyEasily misidentified as Easily misidentified as Ixodes scapularisIxodes scapularis, because they , because they are both collected in the same habitats in spring and fallare both collected in the same habitats in spring and fall

•• Adults active March Adults active March –– November, and easily collected November, and easily collected d i th th t f A td i th th t f A tduring the summer months, except for Augustduring the summer months, except for August

•• No published documentation that they bite humans, but No published documentation that they bite humans, but they feed on many other mammals and at least one birdthey feed on many other mammals and at least one birdthey feed on many other mammals and at least one birdthey feed on many other mammals and at least one bird

•• Common in coastal plain counties of NCCommon in coastal plain counties of NC•• Implicated as an enzootic (or maintenance) vector of Implicated as an enzootic (or maintenance) vector of

Borrelia burgdorferi s.s. Borrelia burgdorferi s.s. in small rodent hosts in South in small rodent hosts in South Carolina and GeorgiaCarolina and Georgia

Photos by Marcee Toliver

affinisfemale

scapularisfemale

Marcee Toliver Marcee Toliver

Ix. affinis female

Marcee Toliver

Ix. affinis male

= large central pores

Marcee Toliver

males(ventral views)

Ix. scapularis( e t a e s)

Ix. affinis

Marcee Toliver

Marcee Toliver

Marcee Toliver

Classic habitat for Ix. affinis is in moist  shaded woods near water

NOT IN DIRECT SUNLIGHT

Marcee Toliver

Known mammal and bird hosts for Ix. affiinis in the USA

Gerrish and Ossorio (1965)

Cotton mouse

Photo by J. Parnell in Webster et al. 1985 in Webster et al.1985

Eastern wood rat

Photo by J. Parnell Photo by J. Parnell inin Webster et al. 1985Webster et al. 1985 in Webster et al.1985

Marsh rice rat

Photo by J. Parnell in Webster et al. 1985

Photo by J. Parnell in Webster et al. 1985

in Webster et al.1985

Hispid cotton rat

Inin Webster et al.1985

Hispid cotton rat

Seasonal (Phenological) Differences

Ixodes affinisIxodes affinis

Marcee Toliver

I odes scap larisc

Ixodes scapularis c

Marcee Toliver, in partM

Some of the Some of the following are following are My Opinions!My Opinions!

(Not everyone in PHPM( ymay agree with me!)

In northeastern U.S.A. the immatures of Ixodes scapularis feed on the

White- footed mouse

pwhite-footed mouse and the adults feed on deer. What is happening along our coast where this mouse does not occur? We still have Lyme cases reported in that area of the

Photo by J. Parnell in Webster et al. 1985cases reported in that area of the state.

IxodesIxodesscapularis

In Webster et al. 1985

?Marcee Toliver

Apperson et al. (1993) established that the primary hosts for Ixodes scapularis larvae and nymphs along the coast in North Carolina are

reptiles. Whether this holds in the piedmont is another question.

Southeastern five-lined skink

Eastern glass lizard

Slender glass lizard

Eastern glass lizard

Photos/maps by Jack Dermid in Beane et al. (2010), Amphibians and Reptiles of the Carolinas and Virginia

Broad-headed skink

What about What about Ixodes affinis Ixodes affinis and Lyme and Lyme diseasedisease inin Virginia?Virginia?gg

You have You have Ixodes affinis Ixodes affinis in southeastern Virginia (Ft. Eustis) and a in southeastern Virginia (Ft. Eustis) and a large concentration of humans in the Norfolk area.large concentration of humans in the Norfolk area.

What do theWhat do the Ix. scapularisIx. scapularis nymphs and larvae in southeastern VAnymphs and larvae in southeastern VA What do the What do the Ix. scapularis Ix. scapularis nymphs and larvae in southeastern VA nymphs and larvae in southeastern VA feed on? Do they feed on reptiles as they do in NE North Carolina?feed on? Do they feed on reptiles as they do in NE North Carolina?

Do you have a second enzootic cycle of Do you have a second enzootic cycle of Borrelia burgdorferi s. sBorrelia burgdorferi s. s. in . in southeastern VA based on the cotton mouse or other rodents beside southeastern VA based on the cotton mouse or other rodents beside the whitethe white--footed mouse?footed mouse?

What are the human case rates for What are the human case rates for B. burgdorferi s. sB. burgdorferi s. s. in . in southeastern VA compared to the rest of the state?southeastern VA compared to the rest of the state?

in Webster et al. 1985 in Webster et al. 1985 in Webster et al. 1985

B.

All Testing Combined:  I. scapularisB.

All Testing Combined:  I. scapularisooooooooooooooo (383 specimens) B. burgdorferi sl, 0, 0%

B

IGSP Pos, 1, 0%

B. burgdorferi sl, 0, 0%

B

IGSP Pos, 1, 0%

oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

Borrelia miyamotoi 0.0% (1/383)

B. bissettii, 0, 0%

B. burgdorferi ss, 3, 1%

B. bissettii, 0, 0%

B. burgdorferi ss, 3, 1%

oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

Borrelia burgdorferi s.s.< 1% (3/383)

Mix, 0, 0%Mix, 0, 0%oo

Neg, 379, 99%

Neg, 379, 99%

M. Toliver, in part

(186 specimens)

B. burgdorferi s.l.1% (2/186)

oooooooooooooooooooooooooooooooB. burgdorferi s.s.

oooooooooooo

31% (58/186)

oBorrelia mixed oooooooooooo

ooooooooooooo

Borrelia mixed3% (6/186)

Marcee Toliver, in part