Module 10: Tick And Vector-Borne Diseases

Question 1

Vector-Borne Illnesses

-Definition/Info

Answer 1

1. Tick-Borne diseases are the most common vector-borne illness
2. Risk factors include:
   —Living in rural areas (suburban area or farm)
   —Having indoor/outdoor pets (especially dog)
   —Presence of a bird feeder in the yard
   —Presence of an outdoor dining area

Question 2

Vector-Borne Illnesses

-Tick-Borne Dz’s Examples

Answer 2

1. Rocky Mountain spotted fever
2. Lyme
3. Ehrlichiosis
4. Tularemia
5. Babesiosis
6. Colorado tick fever
7. Relapsing fever

Question 3

Vector-Borne Illnesses

-Tick-Borne Illness TEST INFO**

Answer 3

1. Transmission — Bites, Transfusion, or congenital
2. Incubation periods — days to weeks
3. Can be confused as viral syndrome
4. When in doubt, TREAT w/ Doxycycline**

Question 4

Vector-Borne Illnesses

-Tick bite Patho

Answer 4

1. 36 hours for bacteria to transfer from the tick into the host
   - bacteria infect locally prior to spreading into the blood and lymph system

Question 5

Vector-Borne Illnesses

-Lyme Disease Overview

Answer 5

1. Borrelia Burgdorferi
   —Spread by the deer tick — upper midwestern and northeastern US — most commonly reported in summer
2. Diagnosis made by — Symptoms, Physical findings (RASH), Exposure
3. Treat w/ appropriate antibiotics
4. Untreated infection can spread to joints, heart, and nervous system

Question 6

Lyme Disease

-Clinical Presentation Stage 1

Answer 6

1. Acute (Localized) Stage
   —incubation 1-30 days
   —Erythema migrans (Bulls-eye rash)**
   —Generalized, flu-like symptoms, Lymphadenopathy

Question 7

Lyme Disease

-Clinical Presentation Stage 2

Answer 7

1. Subacute (Disseminated)
   —Secondary annular rashes
   —Increase in generalized symptoms (Ex: Flu) —malaise, fever, fatigue, urticaria, arthralgias, headaches
   —Incubation in 2wks -10 months

Question 8

Lyme Disease

-Clinical Presentation Stage 3

Answer 8

1. Incubation of months to years
2. Manifestations can include:
   —Neuro, Rhumatological, cardiac, musculoskeletal, vision, integumentary, GI

Question 9

Lyme Disease

-Diagnostics

Answer 9

1. Serology (IgM, IgG) — False negatives occur in acute phase and test can become useless

Two-Tiered Testing
1.

Question 10

Lyme Disease

-Differential Dx’s

Answer 10

1. Bacterial Cellulitis
2. Facial palsies
3. Herpes simplex or zoster
4. Meningitis
5. Reactive arthritis
6. Chronic fatigue syndrome
7. Fibromyalgia

Question 11

Lyme Disease

-Treatment

Answer 11

1. ALWAYS treat empirically if erythema migrans w/ viral s/sx
2. Doxycycline 100mg BID 10-21 days

Question 12

Rocky Mountain Spotted Fever

-Overview

Answer 12

1. Most SERIOUS tick-borne Illness — Bacterial infection spread from bite of infected tick
   —S/S: Vomiting, high fever >102, HA, Abdo pain, rash & muscle aches
2. 60% of cases from — NC, OK, Arkansas, TN, Missouri
3. Curable but potentially LETHAL if not treated w/in the 1st 5 days of symptoms

Question 13

Rocky Mountain Spotted Fever

-Transmission

Answer 13

1. Transmission requires 2 to 20 hours of attachment
   —Bacteria infects vascular endothelial cells
   —Causes SYSTEMIC VASCULITIS

Question 14

Rocky Mountain Spotted Fever

-Clinical Presentation

Answer 14

1. Onset w/in 3-12 days — usually s/s on days 1-4
   -S/S —Fever, Malaise, myalgia, edema around eyes and back of hands,GI N/V/ Anorexia
   —Pt may not have a rash — if rash is present, it is maculopapular small flat pink NON-itchy spot.
   —Rash on wrist, forearm, ankles, — can spread to trunk, palms and soles of feet*
2. LATE Onset Rash — day 6 or later after onset of symptoms
   —Petechial rash is considered sign of progression to severe disease
   —Late s/s: Altered mental status, coma, cerebral edema, ARDS, ambutation, renal failure

Question 15

Rocky Mountain Spotted Fever

-Differential Dx

Answer 15

1. Influenza vs tick-borne dz
2. Meningococcemia
3. Vasculitis
4. 90% of pt’s saw MD in 1st 5 days, but only 50% were treated
5. Independent predictors of failure to treat
   - No rash
   - Presentation w/in 1st 3 days
   - Timing of visit was between August and April

Question 16

Rocky Mountain Spotted Fever

-Diagnostics

Answer 16

1. Serology (IgM, IgG) — IgG more specific than IgM)
   —FALSE negatives in acute phase of illness
2. Results of testing take >5 days — waiting to treat will result in MISSED TREATMENT WINDOW

MUST TREAT in the first 5 DAYS**

Question 17

West Nile Virus

-Overview

Answer 17

1. Leading cause of mosquito borne disease — mosquitoes get the dz from feeding on infected birds
2. NOT spread through coughing, sneezing or touching
3. Most people are asymptomatic
4. Incubation 2-14 days — 1 in 5 infected develop symptoms
5. Febrile Illness — self-limiting generalized symptoms for 3-6 days — fatigue may be long lasting
6. SEVERE ILLNESS
   - Maculopapular rash on chest (SEVERE), back, arms in 25-50%
   - High fever, possible neurological manifestations in 1%

Question 18

West Nile Virus

-High Risk and DIfferentials

Answer 18

1. Risk in elderly/immunocompromised
   —febrile illness — fever, HA, malaise, back pain, myalgias, & anorexia
2. Timing/Location — When to include WNV on differential
   - Confirmed endemic area
   - S/sx during mosquito season w/ febrile illness or acute neuro sx
   - Termperate and tropical climate — year round risk

Question 19

West Nile Virus

-Diagnostics & COllaboration

Answer 19

1. Serology — IgM and/or CSF

2. IMMEDIATELY REFER to Health Department

Question 20

West Nile Virus

-Management

Answer 20

1. Non-Pharm
   —Supportive treatment for generalized symptoms
2. Pharm
   —OTC pain relievers

Question 21

Indications for hospitalization**

Answer 21

1. Heart Block w/ Lyme carditis
2. Petechial rash w/ Rocky Mountain spotted fever
3. Maculopapular Rash with West Nile Virus (No antimicrobial therapy)