Tick-Borne and Zoonotic Diseases in the United States

David Spach, MDProfessor, Division of Infectious Diseases

University of Washington, Seattle

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North American Ticks

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Tick Quiz

From: Spach DH et al. N Engl J Med 1993;329:936-47.

1 2

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Important North American Ticks

Ixodes Female (Adult) Ixodes Male (Adult) Ixodes Nymph

Amblyomma Female (Adult) Dermacentor Female (Adult) Ornithodoros (Adult)

From: Spach DH et al. N Engl J Med 1993;329:936-47. DHS/PP

Ixodes scapularis Ticks

From: CDC Lyme Disease Home Page. www.cdc.gov/ncidod/dvbid/lyme/

Adult Female Adult Male Nymph Larva

Centimeter Scale

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Ixodes Nymph Tick

From: Spach DH et al. Washington State Lyme Disease Monograph. DHS/PP

Case History: Question

A 17-year-old girl presented to the emergency room with lower extremity weakness. She had prolonged recent outdoor exposure. Her weakness was symmetrical and had begun about 8 hours prior to coming to the ER; sensation is intact. A tick is found embedded in her scalp. The most appropriate course of action is:

1. Give IV ceftriaxone x 14 days2. Remove tick and observe closely3. Give IM streptomycin x 10 days4. Arrange for emergent plasmapharesis

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Early Features- Paresthesias- Leg weakness- Absence of fever

Later Findings- Ascending paralysis- Ataxia- Hyporeflexia/Areflexia

Late Findings- Bulbar signs- Hypoventilation

Tick ParalysisClinical Features

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Tick Removal

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A 48-year-old woman presents with myalgias and a painful skin rash on her leg. She recently returned from a one week vacation in eastern Washington and says the rash began one day after she was bitten by something on her leg. The most appropriate course of action is:

1. No antibiotics required2. Give PO Doxycycline for 14 days3. Give IV Ceftriaxone for 14 days4. Give IV Ampicillin and Gentamicin x 10 days

Case History

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Case History

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Tegenaria agrestis (Hobo Spider)

Male Female

From: http://hobospider.org DHS/PP

Recluse Spiders (Loxosceles sp) Distribution in US

From: Vetter RS. DHS/PP

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Diff Dx of Skin Lesions

From: Lowy FD. N Eng J Med 1998;339:520-32.

From: Young DM, et al. Arch Surg 2004;139:951-3.

From: CDC & Prevention

From: CDC & Prevention

From: Darwin Vest

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Case History

A 28-year-old man presented to clinic with a 16 cm erythematous, annular skin lesion on his right flank and flu-like symptoms. He spent the past 30 days hiking in the mountains. The most appropriate course of action is:

1. Give PO Doxycycline for 14 days2. Reassure and don’t give antibiotics3. Draw serology (Lyme) and treat if positive4. Give IV Ceftriaxone for 14 days

Erythema Migrans Rash

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Erythema Migrans Rash

From: Steere AC. N Engl J Med 2001;345:115-25. DHS/PP

Case History

A 33-year-old woman is treated for Lyme disease (erythema migrans) with doxycycline and 12 months later returns and complains of fatigue and muscle aches. She has a friend who takes chronic antibiotics for “Lyme’s disease” and she wants the same.

What would you recommend?

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Antibiotic Treatment for Persistent Symptoms and a History of Lyme Disease

37 4045

30

4036

0

20

40

60

80

100

Imp

rov

ed

%

Seropositive Seronegative All

Ceftriaxone + Doxycycline

Placebo

• Patients- Age > 18 yrs & H/O acute Lyme- Received appropriate Rx- Persistent symptoms (> 6 months)*- Western blot IgG+ (n = 78)- Western blot IgG- (n = 51)

• Regimens (90-day course)- Ceftriaxone 2 g IV qd x 30d, followed by Doxy 200 mg PO qd x 60d - Placebo (matching IV & PO)

Study Design Response at 180 Days

From: Klempner MS et al. NEJM 2001; 345:85-92.

*Widespread musculoskeletal pain; cognitive impairment, radicular pain, paresthesias, dysesthesias

P = NS

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Preferred- Doxycycline: 100 mg PO bid x 14 days- Amoxicillin: 500 mg PO tid x 14 days- Cefuroxime: 500 mg PO bid x 14 days

Alternative - Azithromycin: 500 mg PO qd x 7-10 days - Clarithromycin: 500 mg bid x 14-21 days

Lyme Disease: Erythema MigransTreatment

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National Lyme Disease Risk

From: CDC Lyme Disease Home Page. www.cdc.gov/ncidod/dvbid/lyme/DHS/PP

Case History

A 42-year-old woman is walking in the woods and fields in a coastal New England region and is bitten by a tick.

What further questions would you ask? What would you recommend?

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Doxycycline Prophylaxis After Ixodes Tick Bite

3.2%

0

2

4

6

8

10

Ery

the

ma

Mig

ran

s

Doxycycline

Placebo

0.4%

• Methods - Age > 12 yrs (N = 482) - Westchester County, NY - Removed attached Ixodes tick within previous 72 hours

• Regimens - Doxycycline: 200 mg x 1 - Placebo x 1

Study Design Erythema Migrans

From: Nadelman RB et al. NEJM 2001; 345:79-84. DHS/PP

Doxycycline Prophylaxis After Ixodes Tick Bite

0.0%0

2

4

6

8

10

Ery

the

ma

mig

ran

s

Engorged (At Least Partially)

Flat (Non-engorged)

9.9%

Duration of Tick Feeding: Nymphal Ticks Tick Engorgement: Nymphal Ticks

From: Nadelman RB et al. NEJM 2001; 345:79-84.

0%0

10

20

30

40

50

Ery

the

ma

mig

ran

s

Fed > 72 hours Fed < 72 hours

25%

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Ixodes Adult Females: Unfed and Fed

From: Spach DH et al. Washington State Lyme Disease Monograph. DHS/PP

A 43-year-old man from Westchester county, NY presents with fever and erythema migrans 7 days after a tick bite. He is started on amoxicillin, but 4 days later returns with headache, fever, and myalgias. Labs show leukopenia, thrombocytopenia, and increased hepatic aminotransferase levels. The most appropriate course of action is:

1. Give high dose corticosteroids2. Give PO Doxycycline3. Give IV Ceftriaxone4. Give IV Gentamicin

Case History

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Ehrlichiosis & Anaplasmosis in United States

From: CDC Ehrlichiosis Home Page. www.cdc.gov/ncidod/dvrd/ehrlichia/Index.htm DHS/PP

E. chaffeensis A. phagocytophilium E. ewingii

Ixodes Amblyomma

Monocytes Granulocytes Granulocytes/Eos

Amblyomma

HME HGA HGE

Human Monocytic Ehrlichiosis- Organism: Ehrlichia chaffeensis- Transmission: Amblyomma ticks- Cells: Monocytes/Macophages

Human Granulocytic Anaplasmosis- Organism: Anaplasma phagocytophilium- Transmission: Ixodes ticks- Cells: Granulocytes

Ehrlichiosis & Anaplasmosis

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Ehrlichiosis: Laboratory Studies

Liver Function Tests Platelet Count

From: Fishbein DB et al. Ann Intern Med 1994;120:736-43. DHS/PP

First Line- Doxycycline: 100 mg PO bid x 10 days

Second Line (Doxycycline allergy, Pregnancy)- *Rifampin: 300 mg bid x 10d

Ehrlichiosis & AnaplasmosisTreatment

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*Since rifampin does not treat Lyme disease, patients should also receive amoxicillin or cefuroxime

Case History

A 67-year-old man from Wisconsin develops fever, severe malaise, and dark urine while visiting in Seattle. Two weeks prior he went on a 7-day hunting trip in rural Wisconsin. Labs show HCT = 31 & platelet count = 49,000. Optimal therapy would consist of:

1. Ceftriaxone x 10 days2. Penicillin x 10 days3. Quinine + Clindamycin x 7 days4. Streptomycin x 7 days

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First Line Azithromycin: 500-1000 mg PO day 1, then 250 mg PO qd x 6-9d

plusAtovaquone: 750 mg PO bid x 7-10d

OR

Clindamycin: 300-600 mg IV q6h (600 mg PO q8h) x 7-10 dplus

Quinine: 650 mg of salt PO q8h x 7-10d

Babesiosis: Treatment

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Case History

A 71-year-old geologist presents with a 3-day history of fever, chills, and myalgias. Seven days prior he was in rural eastern Washington and slept in an old cabin. Labs show hematocrit = 42, platelet count 67,000, and an abnormal blood smear. The most likely diagnosis is:

1. Relapsing fever2. Lyme disease3. Leptospirosis4. Colorado tick fever

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From: Spach DH et al. N Engl J Med 1993;329:936-47. DHS/PP

First Line- Doxycycline: 100 mg PO bid x 7-10 days-

Relapsing FeverTreatment

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21%

12%

26%31%

7%1% 3%

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40

50

Pat

ient

s %

0 1 2 3 4 5 6

Relapses

Tick-Borne Relapsing Fever in NorthwestNumber of Relapses

From: Dworkin MS et al. Clin Infect Dis 1998;26:122-31. DHS/PP

A 29-year-old woman is admitted with suspected RMSF. Which laboratory study is NOT often observed with RMSF:

1. WBC > 12, 0002. Platelet count < 150,0003. Hyponatremia4. Increased CSF WBC count

Case History

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RMSF in US 1981-1992: Average Incidence by County

From: Thorner AR et al. Clin Infect Dis 1998;27:1353-9. DHS/PP

RMSF: Clinical Manifestations

From: Catherine Wilfert (Duke University Medical Center) DHS/PP

First Line- Doxycycline: 100 mg PO bid x 7-10 days

Second Line- Chloramphenicol

Promising

- Fluoroquinolones

RMSF: Treatment

From: CDC RMSF Home Pagewww.cdc.gov/ncidod/dvrd/rmsfDHS/PP

Rabies

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• A 29-year-old male is bitten on the shoulder by a bat and the bat escaped. What percent of Rabies Immune Globulin should be given at the wound site?

1. 25%2. 50%3. 75%4. 100%

Case History: Question

Silver-Haired Bat

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“Administer 20 IU/kg body weight.  If anatomically feasible, the full dose should be infiltrated around the wound(s) and any remaining volume should be administered IM at an anatomical site distant from vaccine administration. 

MMWR 1999;48 (RR-1): 275-9.

Rabies Postexposure ProphylaxisRabies Immune Globulin

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From

Rabies: Post-Exposure Prophylaxis

• Wound cleansing

• No RIG

• +Vaccine: day 0 and 3

Previously Vaccinated

Wound cleansing

*RIG

+Vaccine: day 0,3,7,14,28

Not Previously Vaccinated

*Administer vaccine as IM in deltoid+Administer full dose of RIG around wound if possible; remaining volume give at site distant from vaccine site

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• A 22-year-old woman is bitten on the shoulder by a raccoon when she was taking out the garbage at night. The raccoon ran off and has not been seen since this encounter.

• What would you recommend for this woman?

Case History: Question

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“We agree that currently the risk of rabies from the bite of a raccoon that does not exhibit abnormal behavior appears to be low. However, the lack of an active surveillance system for rabies in Washington State makes it incorrect to assume that there are no raccoons or other wild terrestrial carnivores with rabies in our state.”

King County Health Advisory—December 1, 2006

Rabies Postexposure ProphylaxisRaccoon and Other Wild Terrestrial Carnivore Bites

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“Therefore, after consultation with the Centers for Disease Control and Prevention (CDC), Public Health – Seattle & King County continues to recommend rabies PEP for raccoon and other wild terrestrial carnivore bites when the animal is not available for rabies testing.”

King County Health Advisory—December 1, 2006

Rabies Postexposure ProphylaxisRaccoon and Other Wild Terrestrial Carnivore Bites

Case History: Question

• In which of the following scenarios would it NOT be appropriate to administer rabies post-exposure prophylaxis:

1. A 41-year-old woman is bitten by her neighbor’s dog 7 days ago while jogging by their house; the dog is behaving normally

2. A mother awakens and finds a bat in the room of her 4-year-old child (and the bat escapes

3. A 22-year-old man picks up a dead bat in his yard (with bare hands) and throws it down into a large ravine

4. A 48-year-old man tells you during a routine medical visit that he suffered a unprovoked dog bit in Thailand 3 months ago

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Hantavirus Pulmonary Syndrome

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Case History: Question

A 49-year-old woman is admitted to the hospital with a suspected diagnosis of hantavirus pulmonary syndrome. Which of the following would be LEAST characteristic of the clinical presentation of hantavirus pulmonary syndrome?

1. CSF pleocytosis

2. Increased hematocrit

3. Increased white blood cell count with immature forms

4. Thrombocytopenia

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Hantavirus Pulmonary Syndrome: Reservoir

Source: CDC and Prevention

Peromyscus maniculatusDeer Mouse

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*Hantavirus Pulmonary SyndromeThrough March 26, 2007

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*By State of ResidenceSource: CDC and Prevention

Hantavirus Pulmonary Syndrome: Chest Radiograph

CDC

Early Stage

Later Stage

Severe

Interstitial DHS/PP

Hantavirus Pulmonary SyndromeProgression of Disease

Picture

Prodrome Cardiopulmonary

Death

Recovery

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Dog & Cat Exposure

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A 33-year-old woman living in Washington State is bitten on her hand by her cat while trying to break up a fight between her cat and dog. One day later her wound is red and painful and she comes to the ER for evaluation. Which of the following is TRUE?

1. Her risk of getting rabies from this cat bite is about 2%2. Cat bites become infected more often than dog bites 3. Bartonella is the 2nd most likely cause of the infection4. Pseudomonas is 2nd the most likely cause of the infection

Case History: Animal Bite

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Microbiology of Infected Cat Bites

Culture Results (%), N = 57

0 20 40 60 80 100

Pasteurella sp.

Streptococcus sp.

Staphylococcus sp.

Moraxella sp.

Fusobacterium sp.

Bacteroides sp.

Porphyromonas Aerobes

Anaerobes

From: Talan DA, et al. NEJM 1999;340:85-92.DHS/PP

Microbiology of Infected Dog Bites

Culture Results (%), N = 50

0 20 40 60 80 100

Pasteurella sp.

Streptococcus sp.

Staphylococcus sp.

Neisseria sp.

Fusobacterium sp.

Bacteroides sp.

Porphyromonas Aerobes

Anaerobes

From: Talan DA, et al. NEJM 1999;340:85-92.DHS/PP

Dog & Cat Bites Wound Infections: Therapy

Therapy (Oral) - Amoxicillin-CA (Augmentin) x 7-14 days

Therapy (Intravenous - Ampicillin-sulbactam (Unasyn) - Ertapenem (Invanz)

Therapy (Penicillin-Allergic) - Clindamycin plus Fluroquinolone

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Bartonella henselae: Soft Tissue Infection

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From: Bass JW et al. Pediatr Infect Dis 1998;17:447-52.

Cat Scratch Disease: Azithromycin Therapy

0

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100

Pat

ien

ts %

Day 30: 80% Decrease in Lymph Node Volume

Azithromycin (N=14)

Placebo (N=15)

50%

7%

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Cat Scratch Disease Neuroretinitis: Macular Star

From: Bhatti MT et al. Arch Neurol 2001;58:1008-9.

Left Fundus. Eight days later, the infiltrate of the optic nerve is less discrete. Exudates in a star pattern are clearly evident around the fovea.

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This 36-year-old man is admitted to intensive care unit 3 days after suffering a dog bite on his right knee. He has a BP = 85/60, he has diffuse purpura, and lab studies that show evidence of DIC. Tragically, he died 6 hours after admission to the ICU. Which organism likely caused this infection?

1. Moraxella catarrhalis2. Pasteurella canis3. Capnocytophaga canimorus (DF-2)4. Pseudomonas aeruginosa

Case History: Skin & Soft Tissue

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Questions?

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