Tick-Borne and Animal-Associated Diseases

David Spach, MDProfessor of Medicine

Division of Infectious DiseasesUniversity of Washington, Seattle

North American Ticks

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.

Tick Quiz

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

1 2

Case Studies: Tick-Borne Disease

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

· Early Features- Paresthesias- Leg weakness- Absence of fever

· Later Findings- Ascending paralysis- Ataxia- Hyporeflexia/Areflexia

· Late Findings- Bulbar signs- Hypoventilation

Tick ParalysisClinical Features

How should you remove at tick?

Tick Removal

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?

National Lyme Disease Risk

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

Erythema Migrans Rash

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

· Early Disease (Absence of serious Neurologic/Cardiac)- Doxycycline- Amoxicillin

· Late Disease or Serious Neurologic/Cardiac Disease- Ceftriaxone

Lyme Disease: General Approach to Treatment

Case History

A 67-year-old man from Wisconsin develops fever, severe malaise, and dark urine. Two weeks ago he went on a 7-day hunting trip in rural Wisconsin. Labs show hematocrit = 31 and platelet count = 49,000.

The most likely diagnosis and treatment?

Babesiosis: Transmission

Ticks- Ixodes scapularis- Ixodes pacificus

Transfusion-Associated- RBCs- Platelets

· First Line- Clindamycin plus Quinine

· Second Line- Azithromycin plus Atovaquone

Babesiosis: Treatment

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

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

Ornithodoros Tick

· First Line- Doxycycline

· Second Line- Erythromycin

Tick-Borne Relapsing Fever: Treatment

A 29-year-old woman is admitted with suspected RMSF.

Which finding is NOT often observed with RMSF:

1. WBC > 12,0002. Platelet count < 150,0003. Rash that begins on extremities4. Exposure to a Dermacentor tick

Case History

RMSF in US 1981-1992: Average Incidence by County

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

RMSF: Clinical Manifestations

From: Catherine Wilfert (Duke University Medical Center)

· First Line- Doxycycline

· Second Line- Chloramphenicol

Rocky Mountain Spotted Fever: Treatment

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 transaminases. The most appropriate course of action is:

1. Give high dose corticosteroids

2. Give PO Doxycycline

3. Give IV Ceftriaxone

4. Give IV Gentamicin

Case History

Ehrlichiosis & Anaplasmosis in United States

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

E. chaffeensis A. phagocytophilium E. ewingii

Ixodes Amblyomma

Monocytes Granulocytes Granulocytes/Eos

Amblyomma

HME HGA HGE

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

· Second Line- Chloramphenicol- Rifampin

Ehrlichiosis: Treatment

Rabies

In the United States, how do most

people get rabies?

• 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

“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. 

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

Rabies Postexposure ProphylaxisRabies Immune Globulin

Rabies: Post-Exposure Prophylaxis

Wound cleansing

*Rabies Immune Globulin

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

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

*Note: Number of recommended doses of rabies vaccine changed from 5 to 4 (ACIP June 24, 2009)

From: CDC. MMWR 2008;57:1-26.

Hantavirus Pulmonary Syndrome

Case History: Question

What is the main reservoir for Hantavirus in the United States?

1. Deer mice2. Deer3. Mosquitoes4. Horned nose black fly

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

Hantavirus Pulmonary Syndrome: Reservoir

Source: CDC and Prevention

Peromyscus maniculatusDeer Mouse

*Hantavirus Pulmonary SyndromeThrough November 11, 2009

*By State of ExposureSource: CDC and Prevention

Hantavirus Pulmonary Syndrome: Chest Radiograph

CDC

Early Stage

Later Stage

Severe

Interstitial

Hantavirus Pulmonary SyndromeProgression of Disease

Picture

Prodrome Cardiopulmonary

Death

Recovery

Hantavirus Pulmonary SyndromeTherapy

Careful volume replacement (PAP=12-15 mm)

Vasopressors -Dopamine -Dobutamine

Extracorporeal membrane oxygenation (ECMO)

Intravenous Ribavirin? - NIH Trial (1-888-866-7257)

52-year-old previously healthy woman presents to urgent care following a macaque monkey bite? The patient works as a researcher at a primate laboratory at the UW.

What is the name of the organism you are concerned about that she may have acquired from this macaque bite?

What therapy would you recommend?

1. Amoxicillin-clavulanic acid + Zidovudine2. Amoxicilin-clavulanic acid + Valacyclovir 3. Moxifloxacin + Interferon-alpha4. Moxifloxacin + Entecavir + Ribavirin

Case History: Question

Case History

B Virus (Cercopithecine herpesvirus 1)

Endemic among macaque monkeys Shedding from oral, conjunctival, or genital mucosa Incubation: 2-35 days (most 5-21 days after exposure) Clinical infection: vesicular rash, peripheral NS, CNS Mortality rate if untreated: 80%

From: Cohen JI. Clin Infect Dis 2002;35:1191-203.

B Virus (Ceropithecine herpesvirus 1)

Prophylaxis(1) Valacyclovir: 1g PO q8h x 14 days(2) Acyclovir: 800 mg PO 5x/day x 14 days

Treatment (NO CNS Symptoms)(1) Acyclovir: 12.5-15.0 mg/kg IV q8h(2) Ganciclovir: 5 mg/kg IV q12h

Treatment (CNS Symptoms Present)(1) Ganciclovir: 5 mg/kg IV q12h

From: Cohen JI. Clin Infect Dis 2002;35:1191-203.

Dog & Cat Exposure

Case History

· A 28-year-old healthy woman is scratched on her neck by cat and 1 week later develops a scab at the site. Three weeks later she develops preauricular and postauricular adenopathy.

· The most likely organism and appropriate treatment are:

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

Cat Scratch Disease: Azithromycin Therapy

A 26-year-old woman is bitten on her leg by her dog while trying to break up a dog fight. 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 dog bite is about 15%2. Pasturella is rarely involved in dog bites3. Cat bites become infected more often than dog bites4. Anaerobic organisms are more common in dog bite than cat bite infections

Case History: Skin & Soft Tissue

Pasturella sp.

Streptococcus sp.

Staphylococcus sp.

Neisseria sp.

Fusobacterium sp.

Bacteroides sp.

Porphyromonas

0 20 40 60 80 100

Culture Results (%), N = 50

AerobesAnaerobes

Microbiology of Infected Dog Bites

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

Microbiology of Infected Cat Bites

Pasturella sp.

Streptococcus sp.

Staphylococcus sp.

Moraxella sp.

Fusobacterium sp.

Bacteroides sp.

Porphyromonas

0 20 40 60 80 100

Culture Results (%), N = 57

Aerobes

Anaerobes

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

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

Questions/Wrap-Up