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LYME DISEASE IN

MICHIGAN:ecology, epidemiology, and prevention

Erik Foster, MS Medical Entomologist

Emerging & Zoonotic Infectious Diseases Section

February 24, 2017

LYME DISEASE: most common vector-borne disease in the US1

VECTOR: ticks

Ixodes scapularis (AKA blacklegged or deer tick)

PAHTOGEN: Borrelia burgdorferi

1. (CDC MMWR, 2013; Steer et al. 2004)

Quick background

Copyright © M. Plonsky. All rights reserved.

History of Lyme

197651 cases of “apparently similar arthritis,” characterized by recurrent attacks of pain and swelling in large joints. Others had fever, headaches, weakness and a skin rash as well. One quarter of patients had an unusual skin lesion before the onset of joint symptoms.

1976Several cases of arthritis in children were reported. The Department of Health and the Yale University School of Medicine planned a joint survey to detect additional cases in the area and describe the disease in detail.

Douglas S. Lloyd, M.D., M.P.H.Health Commissioner

1976The seasonal and geographic distribution, and the associated skin lesion suggested a “virus” associated with a “biting insect.”1

1. Lloyd, D.S. Circular Letter #12-32 to Connecticut Directors of Health. August 3, 1976.

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History of Lyme

1909Swedish dermatologist Arvid Afzelius described an expanding, ring-like lesion following the bite of a sheep tick. He named the lesion erythema migrans (EM).

1970Wisconsin dermatologist, Rudolph Scrimenti, recognized an EM lesion in a patient after recalling description of the rash in European literature. This was the first documented case of EM in the United States2.

2. Scrimenti, R.J. 1970. Erythema chronicum migrans. Arch Dermatol 102 (1): 104–05

History of Lyme

1980NYS HD Epidemiologist Jorge Benach provided Willy Burgdorfer, researcher at Rocky Mountain Biological Laboratory, collections of Deer ticks (Ixodes scapularis) from a known Lyme-endemic area.

1980While examining the ticks for Rickettsia, Willy noticed “poorly stained, rather long, irregularly coiled spirochetes” in 60% of the ticks. He realized that the spirochetes might be the “long-sought cause of EM and Lyme disease.”

1980Coordinating with Alan Barbour of U-Texas, Willy was able to isolate the spirochetes from patients with Lyme disease. The spirochete was named Borrelia burgdorferiin his honor.3

3. Burgdorfer W., et al. (1982). Lyme disease-a tick-borne spirochetosis?. Science 216 (4552): 1317–19.

Ticks will embed their mouthparts in the skin, and may be difficult to detect due to their small size. Prompt removal of ticks is preventative for Lyme disease as studies have shown it takes >36 hours for efficient B. burgdorferi transmission to occur.

People come into contact with ticks while working or recreating in wooded areas or areas with shade and vegetation, which is the preferred habitat for Blacklegged ticks.

Lyme bacteria

Lyme disease is maintained in nature through a cycle of infection between Blacklegged ticks and small mammals.

Ecology of Lyme disease

“Questing” Tick

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National maps and statistics available at www.cdc.gov

?

U.S. Lyme disease biogeography

Public health significance

In 2013, Lyme disease was the 5th most commonly reported notifiable disease in the U.S.

(1. Chlamydia, 2. Gonorrhea, 3. Syphilis, 4. Salmonellosis)

Approximately 3.4 million LD tests nationwide in 2008 from 7 large commercial laboratories4

Cost estimates for laboratory services of $492 million

Estimate 288,000 LD cases/year

2005-2010 Truven Health MarketScan Commercial Claims and Encounters Database analyzed5

Estimate 329,000 LD cases/year

4. Hinckley, A.F., et al. 2014. Lyme disease testing by large commercial laboratoires in the United States. Clin Infect Dis. 59 (5): 676-681.5. Nelson, C.A., et al. 2015. Incidence of clinician-diagnosed Lyme disease, United States, 2005–2010. Emerg Infect Dis. 21(9). 1625-1631.

Public health significance

CDC Estimate:(approx. 10x underreporting)

288,000 - 329,000 cases annuallyNelson CA, Saha S, Kugeler KJ, Delorey MJ, Shankar MB, Hinckley AP, et al. 2015. Incidence of clinician-diagnosed Lyme disease, United States, 2005–2010. Emerg Infect Dis. 21(9). 1625-1631.

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First detection of ticks, pathogen, and cases: Michigan’s UP late ‘80s, early ‘90s

1992

1992

1990

Iron

Delta

Luce

Kent

MarquetteAlger

Chippewa

Gogebic

Huron

Sanilac

BaragaOntonagon

Ionia

Lake

Bay

Allegan

Schoolcraft

Oakland

Barry

Clare

Houghton

Mackinac

Iosco

Tuscola

Alcona

Cass

Eaton

St Clair

Lapeer

Saginaw

Newaygo

JacksonWayne

Calhoun

Alpena

Gratiot

Lenawee

ClintonOttawa

Antrim

Berrien

Dickinson

Mason

Ingham

Isabella

Montcalm

Oscoda

MonroeBranch

Otsego

Hillsdale

Genesee

Osceola

Oceana

Wexford

Emmet

Mecosta Midland

Ogemaw

Gladwin

Kalkaska

Washtenaw

Crawford

Manistee

Van Buren

Livingston

Presque Isle

Missaukee

St Joseph

Arenac

Benzie

Leela

nau

Charlevoix

Men

omin

ee

Cheboygan

Macomb

Kal

amaz

oo

Muskegon

Ros

com

mon

Shi

awas

see

Montm

orenc

y

GrandTraverse

Keweenaw

2016 Michigan Lyme Disease Risk Map (Dec. 2016)

Blacklegged ticks and risk for Lyme disease are emerging in Michigan

Ran

ge E

xpan

sio

n 2

002

-201

6

Tick populations are affected by:

• Local temperature

• Precipitation

• Soil type

• Drainage

• Host species

• Land use/ cover

Copyright © M. Plonsky. All rights reserved.

What is a tick?

Ticks are more closely related to spiders and mites than insects

They must feed on blood to complete their life cycle

Ticks feed on a variety of animals from small and medium sized mammals, to birds and lizards

It is generally within the enzootic, or tick/animal cycle that tick-borne diseases are maintained

There are two major families of ticks

Argasidae – Soft ticks

Ixodidae – Hard ticks

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How do ticks sense their environment?

Unlike insects ticks have no antennaeUnlike insects or spiders, hard ticks have 2 simple eyes or no apparent eyesTicks sense their environment with sensory organs on their legs and palpsThey can detect heat, CO2, movement, and other ticks

Compound eye

Antennae

Simple eye

Palps

How do ticks find their prey?

The ticks that concern us in human health in the U.S. find their prey by “questing”

Ticks climb onto vegetation to await a passing animal often along animal and man-made trails

They may also crawl short distances in response to CO2

Ticks DO NOT jump, fly, or drop onto people from trees

How do ticks feed?Ticks will search the host for an appropriate attachment site

Typically the hairline, behind the ears, armpits, groin, behind knees, waistline

Chelicerae, which are like saws will begin to pierce the skinHypostome is guided through into the woundCement is rapidly secreted to create firm attachment to the hostSalivary compounds are secreted to create a “feeding lesion” or hematoma in the dermis

Includes antihistamines and anticoagulants

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Ticks are common in Michigan

1 mmDermacentor variabilis (American dog tick or wood tick)• Found in wooded and brushy habitats• Most common tick in Michigan• Oval scutum with white markings, brown

abdomen• Adults commonly bite and are active from early-

spring through the end of summer• Vector: Rocky Mountain spotted fever

Ixodes scapularis (blacklegged tick)• Common in wooded and brushy habitats• Smaller size than D. variabilis• Rounded, black scutum, red or gray abdomen• Adults and nymphs will readily bite people.

Adults: April – July, October – NovemberNymphs: May – August

• Vector: Lyme disease, anaplasmosis, babesiosis, deer tick virus, Ehrlichia muris-like

Image: Erik Foster, MDCH

Images: Kent Loeffeler, Cornell University

What is the Blacklegged tick life cycle?

Egg

Spring

Larvae

Early Summer

Nymph

Next Spring/Summer

Adult

Fall/Next Spring

White-tailed deer do

not cycle the disease

People become unwilling

participants by recreating

or working in tick infested

habitats

Immature ticks feed primarily

on small mammals. These

mammals are the primary

reservoir of Lyme disease

Blacklegged tick nymphsNymphs are the stage most responsible for the majority of Lyme disease illness in the United States. This is due to:

Small size

First infectious stage

Active during peak outdoor recreation periods in the NE and Upper Midwestern U.S.

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Not all ticks are infected

Only blacklegged ticks transmit Lyme disease

Only two stages of blacklegged ticks transmit Lyme disease

Nymph

AdultFemale

36-40%B. burgdorferi infection rate

Nymph 9-15%B. burgdorferi infection rate

Hamer et al., 2010; Foster, 2004.

Who does tick-borne disease affect?Anyone working or recreating in forested or forest-edge habitats, including:

Man-made trail systems

Trails used by animals

Campgrounds

Brushy or grassy areas near buildings or yards

Wooded river banksMSPS member, Matthew Dontz, with son Tyler- a future member!

Lyme disease “re”emergenceReforestationOverabundant deerIncreased numbers of ticksExpansion of suburbia into wooded areasIncreased exposure opportunitiesChanges in diagnostic, surveillance, and reporting practicesMichigan circa 1890’s

© Detroit Publishing Company

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Tick habitat suitability

model6

ParametersForest type

Soil typeLand coverSoil texture

Bedrock

6. Guerra M., et al. 2002. Predicting the Risk of Lyme Disease: Habitat Suitability for Ixodes scapularis in the North Central United States. Emerg Infect Dis. 8(3). 289-297.

Environmental risk determination

MDARD & MDHHS

Established tick identification and testing program for

Michigan residents.

MDNR, MSU, & MDHHS

Collaborative field surveillance for establishing tick populations

and B. burgdorferi infection.

Tick “drags”Mammal and bird trappingHunter-killed deer samplingVeterinary clinic surveillance

UP Tick Survey 2015

Isis Arsnoe, 2015

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MI cases have increased over time

Emerging & Zoonotic Infectious Diseases SectionMichigan Department of Health & Human ServicesFebruary 7, 2017

0

20

40

60

80

100

120

140

160

180

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

No

. C

ases

Year

Lyme disease cases by year, Michigan 2002-2015

Unknown ExposureOut-of-State ExposureIn-State Exposure

Lyme disease by age group, 2002-2015

Emerging & Zoonotic Infectious Diseases SectionMichigan Department of Health & Human ServicesFebruary 7, 2017

0

2

4

6

8

10

12

14

16

18

20

</=1

yea

r

2-10

yea

rs

11-2

0 y

ears

21-3

0 y

ears

31-4

0 y

ears

41-5

0 y

ears

51-6

0 y

ears

61-7

0 y

ears

>/=7

1yea

rs

Rep

rese

nta

tive

Rat

e (S

tate

wid

e %

)

Age group

Lyme disease by gender

Emerging & Zoonotic Infectious Diseases SectionMichigan Department of Health & Human ServicesSeptember, 2016

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Race & ethnicity of Lyme disease cases

White

American Indianor Alaka Native

Black or AfricanAmerican

Asian

Unknown

85% white

Emerging & Zoonotic Infectious Diseases SectionMichigan Department of Health & Human ServicesSeptember, 2016

0

5

10

15

20

25

30

35

40

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Western MI Exposure

UP MI Exposure

Other MI Exposure

Out of State Exposure

Nymphs

Adults

Blacklegged tick activity

Onset month

Reported Lyme disease cases in Michigan: 2015 EPI Curve

Emerging & Zoonotic Infectious Diseases SectionMichigan Department of Health & Human ServicesSeptember, 2016

# C

ases

Clinical Manifestations of Confirmed Lyme Disease Cases--US, 2001-2010

http://www.cdc.gov/lyme/stats/chartstables/casesbysymptom.html

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Begins at the site of a tick bite after a delay of 3 to 30 daysExpands gradually“Bull’s-eye” appearance

70% of infected persons have Erythema migrans (EM) rash

Photo: CDC/James Gathany

FeverChillsHeadacheFatigueMuscle and joint aches Swollen lymph nodes

Other symptoms 3 to 30 days after tick bite include:

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Weeks to months after infectionPain and swelling in the large joints

Facial or Bell's palsy

Shooting pains that may interfere with sleep

Severe headaches and neck stiffness due to meningitis

Heart palpitations and dizziness

Early disseminated stage

If not appropriately treated:

intermittent bouts of arthritis, with severe joint pain and swelling

chronic neurologic complaints:shooting pains

numbness or tingling in the hands or feet

problems with short-term memory

Late disseminated stage

Some symptoms may persist even after treatment

muscle and joint pains

cognitive defects

sleep disturbance

fatigue

called Post-treatment Lyme disease Syndrome

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Lyme carditis

The most important factors in preventing Lyme disease are:

1. Knowing where ticks can be encountered2. Preventing tick bites3. Removing ticks promptly if they do bite4. Seeking prompt medical care if illness occurs after exposure to ticks

Key driver: increase and spread of blacklegged ticks

1907-1996 (Dennis et al. 1998)

1907-2015(Eisen et al. 2016)

Established tick populations: ≥ 6 ticks or 2 life stages in a single year

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Preventing tick bites

Wear light-colored clothing with a tight weave so ticks can be spotted easily.

Wear closed-toe shoes, long pants, and a long sleeved shirt. Tuck pant legs into socks or boots and shirt into pants.

Check clothes and any exposed skin frequently for ticks.

Avoid sitting directly on the ground, fallen logs, or stone walls.

Personal protective measures

EPA-approved skin repellents:DEET, Picardin, oil of lemon eucalyptus

EPA-approved clothing repellent:

Permethrin

Preventing tick bites

Remove ticks from your clothes before going indoors.

To kill ticks that you may have missed, wash your clothes with hot water and dry them using high heat for at least one hour.

Perform daily tick checks after being outdoors, even in your own yard. Inspect all parts your body carefully, including your armpits, scalp, and groin.

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Probability of LD transmission

des Vignes et al., 2001. Effect of tick removal on transmission of Borrelia burgdorferi and Ehrlichia phagocytophila by Ixodes scapularis nymphs. JID

Removing blacklegged ticks promptly can help prevent Lyme disease!Probability of Lyme disease transmission by blacklegged tick nymphs over time

What should I do if I’m bitten by a tick?

If a tick is attached to you, use fine-tipped tweezers or similar tool to grasp the tick at the surface of your skin.

Pull the tick straight up and out. Don’t twist or jerk the tick—this can cause the mouth parts to break off and stay in the skin. If this happens, remove the mouth parts with tweezers if you can. If not, leave them alone and let your skin heal.

Clean the bite and your hands with rubbing alcohol, an iodine scrub, or soap and water.

You may get a small bump or redness that goes away in 1-2 days, like a mosquito bite. This is not a sign that you have Lyme disease.

How to remove a tick?

Use tweezers and just pull out from closest point of attachment to body and try not to leave mouthparts in, which could lead to a secondary infection.

Then wash area with soap & water and apply antiseptic.

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At the end of the day, also check your dog, cat, and horse companions!

Expert tick identification is available at a number of state agencies.Place the tick in a small vial containing a damp piece of tissue orpiece of grass and submit it to the appropriate agency, following theguidelines for tick identification and testing found at:www.michigan.gov/lyme.

This service is free to the public for ticks removed from residents in Michigan.

Tick ID and Testing!

When to see your doctor

See a doctor if you develop a fever, a rash, severe fatigue, facial paralysis, or joint pain within 30 days of being bitten by a tick. Be sure to tell your doctor about your tick bite. If you have these symptoms and spent time outdoors where Lyme disease is common, it is important to get treatment right away.

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More resources available online

www.michigan.gov/lyme www.cdc.gov/lyme

The future?

Likely that Michigan will see increased tick populations, and increased Lyme disease risk

Other pathogens associated with blacklegged ticks, such as Anaplasma and Babesia will also increase

Michigan agencies (MDNR, MDHHS) will need to continue educating the public regarding tick-bite and tick-borne disease prevention

Borrelia mayonii recently discovered in WI and MN, is more virulent than B. burgdorferi.