4. Tick-Borne Infections

What is the causative organism of Lyme Disease?

Borrelia burgdorferi (a spirochete).

What is the primary vector for Lyme Disease?

The Ixodes tick (Deer tick).

What is the hallmark skin lesion of early localized Lyme Disease (Stage 1)?

Erythema Migrans (the 'bull's-eye' rash).

Describe the clinical presentation of Stage 2 (Early Disseminated) Lyme Disease.

Multiple secondary annular rashes, Bell's palsy (CN VII) or meningitis, AV heart block.

What is a classic manifestation of Stage 3 (Late) Lyme Disease?

Chronic monoarticular arthritis (commonly affecting the knee).

What is the first-line treatment for Lyme Disease (Early and Late)?

Doxycycline (usually 100mg BID x 10-21 days).

What is the alternative treatment for pregnant women or young children (<8 years) with Lyme Disease?

Amoxicillin or Cefuroxime.

What is the causative organism of Rocky Mountain Spotted Fever (RMSF)?

Rickettsia rickettsii.

What is the vector for RMSF?

The Dog tick (Dermacentor).

Describe the classic rash of RMSF.

A blanching, erythematous rash with macules that become petechial, beginning on the wrists and ankles and spreading centrally.

What is the classic triad of symptoms for RMSF?

Fever, Headache, and Rash.

What is the drug of choice for RMSF, including in children?

Doxycycline.

What laboratory abnormality is commonly seen in RMSF?

Thrombocytopenia (low platelets) and Hyponatremia (low sodium).

What is the vector for Ehrlichiosis?

The Lone Star tick (Amblyomma americanum).

How does Ehrlichiosis clinically differ from Lyme or RMSF?

It presents with 'spotless' RMSF symptoms (High fever, headache, myalgia) but usually no rash.

What is the pathognomonic finding on a blood smear for Babesiosis?

The 'Maltese Cross' formation inside red blood cells.

Which tick-borne disease mimics malaria and causes hemolytic anemia?

Babesiosis.

What is the most common pathogen implicated in cat and dog bites?

Pasteurella multocida.

What is the first-line antibiotic prophylaxis/treatment for animal bites (cat/dog/human)?

Amoxicillin-Clavulanate (Augmentin).

What organism causes Cat Scratch Disease?

Bartonella henselae.

What is the typical clinical presentation of Cat Scratch Disease?

A papule/pustule at the scratch site followed by tender regional lymphadenopathy.

What is the treatment for Cat Scratch Disease?

Usually supportive; Azithromycin can be used in severe cases.

What is the post-exposure prophylaxis (PEP) protocol for Rabies?

Immediate and thorough wound cleaning, Rabies Immune Globulin, and a series of Rabies Vaccine injections.

What is the risk factor associated with Lyme Disease?

Exposure to tick-infested areas.

In which regions is Lyme Disease most commonly found?

Northeastern, north-central, and Pacific coastal regions of the United States.

What time of year do most Lyme Disease infections occur?

Late spring and summer.

What is the incubation period for Lyme Disease?

3 to 30 days after being bitten by an infected tick.

How is Lyme Disease diagnosed?

Diagnosis is primarily based on clinical findings and history of tick exposure.

What is a common neurological complication of late Lyme Disease?

Cognitive dysfunction or peripheral neuropathy.

What is the estimated number of new Lyme Disease cases reported in the U.S. annually?

Approximately 300,000.

What is the common age group affected by Lyme Disease?

Individuals aged 5-14 years and adults aged 45-54 years.

What are common systemic symptoms of Lyme Disease?

Fatigue, fever, chills, and muscle aches.

What is the main diagnostic test for Lyme Disease?

Enzyme-linked immunosorbent assay (ELISA) followed by Western blot for confirmation.

What is a key characteristic of the rash seen in Lyme Disease?

It can expand over time and clear centrally.

What is a significant complication of untreated RMSF?

Acute respiratory distress syndrome (ARDS) and renal failure.

What is the mortality rate of RMSF if untreated?

Up to 25%.

What general category of diseases do RMSF and Lyme Disease belong to?

Vector-borne diseases.

What season is noted for the peak activity of the Dog tick?

Spring and early summer.

What symptom may appear late in RMSF?

The rash.

What is the typical duration of treatment for RMSF with Doxycycline?

5 to 7 days.

What is an important preventive measure against RMSF?

Tick avoidance and use of insect repellent.

What is a common demographic of patients with Ehrlichiosis?

Middle-aged adults.

What is a distinguishing feature of the rash in RMSF compared to other rashes?

The rash may start as small pink spots that develop into petechiae.

What is the recommended preventative measure for Ehrlichiosis?

Wear long sleeves and pants in wooded areas.

What lab tests can indicate Ehrlichiosis?

Complete blood count typically shows leukopenia and thrombocytopenia.

Which antigen test can help diagnose Babesiosis?

Blood smear demonstrating the 'Maltese Cross'.

Which tick-borne illness requires immediate hospitalization if diagnosed?

Rocky Mountain Spotted Fever.

What year was Babesiosis first recognized in the U.S.?

1969.

What are the effects of Babesiosis on red blood cells?

Infection leads to hemolysis and tissue hypoxia.

What is a classic laboratory finding in Babesiosis?

Parasitemia in red blood cells.

What is the incubation period for Babesiosis?

1 to 4 weeks after being bitten by an infected tick.

How does Babesiosis typically present clinically?

With flu-like symptoms including fevers, chills, and sweats.

What is a significant risk factor for severe Babesiosis?

Immunocompromised status of the patient.

What type of bacteria is Bartonella henselae?

A gram-negative bacillus.

What is the classic finding in lymph nodes affected by Cat Scratch Disease?

Tender lymphadenopathy.

What is the treatment of choice for severe cases of Cat Scratch Disease?

Azithromycin.

What animal behavior can increase the risk of Cat Scratch Disease?

Playing with or being scratched by a kitten.

What preventive measure can be taken to avoid animal bites?

Supervise young children around pets.

What is a potential risk associated with handling animals that have been bitten by other animals?

Transmission of zoonotic infections.

What is the infectious dose for rabies virus?

As few as 1-10 virus particles.

What is the duration for Rabies Vaccine treatment after exposure?

A series of 4 injections on days 0, 3, 7, and 14.

What is the effect of rabies on the central nervous system?

It causes encephalitis and neurological symptoms.

How does rabies typically manifest before symptom onset?

With a prodrome stage including fever and malaise.

What is the purpose of Rabies Immune Globulin (RIG) in post-exposure prophylaxis?

To provide immediate passive immunity.

What should be done immediately after a potential rabies exposure?

Thorough washing of the wound.

What is the most common cause of infection following dog bites?

Pasteurella multocida.

What type of infection is caused by Cat Scratch Disease?

A self-limiting infection.

What is an essential part of the clinical approach to animal bites?

Assessing the risk of rabies.

What are common clinical features of rabies in later stages?

Hydrophobia, paralysis, and eventually coma.

What characterizes the rash of RMSF at the onset?

It is typically non-blanching.

What factors contribute to Lyme Disease transmission?

Favorable tick habitats and lack of protective clothing.

What are common diseases caused by bites from rabid animals?

Rabies.

What is a key symptom of severe Lyme Disease that distinguishes it from other tick-borne diseases?

Joint swelling and pain.

What other conditions can mimic Lyme Disease?

Fibromyalgia and chronic fatigue syndrome.

What is a common misdiagnosis for RMSF in its early stages?

Viral illness.

What is the incubation period for RMSF?

2 to 14 days post tick bite.

What is a significant risk of untreated Lyme Disease over long periods?

Chronic joint issues or neurologic deficits.

What is a common geographic area for Babesiosis?

Northeast and upper Midwest of the USA.

What serological test is used for Lyme Disease diagnosis?

Western blot.

What symptoms often prompt the evaluation for Lyme Disease?

Rash and flu-like symptoms after potential tick exposure.

Which demographic is least likely to be affected by Ehrlichiosis?

Urban dwellers, as it's more common in rural areas.

What can happen to humans if they handle ticks improperly?

Increased risk for infection.

What is a recommendation for travelers to areas endemic to Lyme Disease?

Check for tick attachment after being outdoors.

What can reduce the incidence of rabies in domestic animals?

Regular vaccination.

What is a supportive treatment for mild cases of Cat Scratch Disease?

Rest and pain management.

What are common signs of feline parvovirus that may be confused with Cat Scratch Disease?

Anorexia and lethargy.

What are the counseling points for rabies prevention in pets?

Maintain vaccinations and avoid wild animals.

What is a distinguishing feature of Lyme Disease compared to RMSF?

The presence of the characteristic 'bull's-eye' rash.

What type of mosquitoes primarily spread zoonotic diseases?

Aedes and Culex mosquitoes.

What is the long-term health effect of untreated Lyme Disease?

Possibility of developing post-treatment Lyme disease syndrome.

What is the role of the CDC in managing zoonotic diseases?

Surveillance, research, and guiding prevention strategies.

What is the geographic distribution of Rickettsia rickettsii in the U.S.?

Primarily in the southeastern and south-central states.

What should be monitored before administering antibiotics for animal bites?

Allergies to the medication.

How long does rabies virus remain viable in the environment?

Several hours to a few days depending on conditions.

What is the recommended treatment for confirmed rabies exposure?

Immediate wound cleaning and rabies vaccination series.

What type of environment is associated with higher incidence of tick-borne diseases?

Forested and grassy areas.

What is an important public health initiative regarding Lyme Disease?

Awareness and education on tick prevention.

What symptom indicates possible severe Babesiosis?

Persistent high fever.

What is important to inform patients about while they receive treatment for rabies?

The significance of completing the vaccination series.

What educational point is vital for preventing animal bites in children?

Teaching gentle handling of pets.