Podcast
Questions and Answers
What is the primary mode of transmission for Leptospirosis from animals to humans?
What is the primary mode of transmission for Leptospirosis from animals to humans?
- Direct or indirect contact with urine-contaminated environments. (correct)
- Consumption of undercooked meat from infected animals.
- Transmission via arthropod vectors such as ticks or mosquitoes.
- Inhalation of aerosolized bacteria from contaminated water sources.
Which characteristic of Leptospira interrogans contributes most to its ability to disseminate within a host?
Which characteristic of Leptospira interrogans contributes most to its ability to disseminate within a host?
- Its slow growth rate, allowing for undetected proliferation.
- Its Gram-negative bacterial structure enhancing immune evasion.
- Its motility, facilitating movement through tissues and bloodstream. (correct)
- Its obligate anaerobic nature, allowing survival in oxygen-poor environments.
Which environmental condition is least conducive to the survival of Leptospira interrogans?
Which environmental condition is least conducive to the survival of Leptospira interrogans?
- Moist organic matter.
- Infected animal urine.
- Contaminated soils.
- Direct sunlight. (correct)
A researcher aims to study the survival rate of Leptospira interrogans in different soil samples. Which factor would least likely affect the outcome of this experiment?
A researcher aims to study the survival rate of Leptospira interrogans in different soil samples. Which factor would least likely affect the outcome of this experiment?
Given that Leptospira interrogans is an obligate aerobe, in which environment would it least likely proliferate?
Given that Leptospira interrogans is an obligate aerobe, in which environment would it least likely proliferate?
Which of the following is the most likely route of Leptospira transmission in individuals who develop leptospirosis after participating in water sports?
Which of the following is the most likely route of Leptospira transmission in individuals who develop leptospirosis after participating in water sports?
A patient presents with jaundice, renal failure, and hemorrhage. Which of the following pathophysiological mechanisms is most directly associated with the jaundice observed in this patient?
A patient presents with jaundice, renal failure, and hemorrhage. Which of the following pathophysiological mechanisms is most directly associated with the jaundice observed in this patient?
A patient in the septicemic phase of leptospirosis is experiencing a high fever, headache, myalgias, and conjunctival suffusion. Which of the following additional symptoms would be most indicative of meningeal irritation in this patient?
A patient in the septicemic phase of leptospirosis is experiencing a high fever, headache, myalgias, and conjunctival suffusion. Which of the following additional symptoms would be most indicative of meningeal irritation in this patient?
A patient diagnosed with Weil's syndrome develops sudden cardiac arrhythmia and circulatory collapse. Which of the following complications of Leptospira infection is most likely contributing to these acute cardiovascular issues?
A patient diagnosed with Weil's syndrome develops sudden cardiac arrhythmia and circulatory collapse. Which of the following complications of Leptospira infection is most likely contributing to these acute cardiovascular issues?
Which confirmatory diagnostic test requires acute and convalescent serum samples to detect Leptospira?
Which confirmatory diagnostic test requires acute and convalescent serum samples to detect Leptospira?
A patient is suspected of having leptospirosis, but the organisms cannot be seen using a Gram stain. Which of the following diagnostic tests is most appropriate to use during the first week of suspected infection?
A patient is suspected of having leptospirosis, but the organisms cannot be seen using a Gram stain. Which of the following diagnostic tests is most appropriate to use during the first week of suspected infection?
A leptospirosis patient's lab results show elevated creatinine, proteinuria, and hematuria. Which organ system is primarily affected, based on these findings?
A leptospirosis patient's lab results show elevated creatinine, proteinuria, and hematuria. Which organ system is primarily affected, based on these findings?
Which of the following interventions provides the MOST effective means of preventing leptospirosis in humans?
Which of the following interventions provides the MOST effective means of preventing leptospirosis in humans?
Flashcards
What is Leptospirosis?
What is Leptospirosis?
A spirochetal infection transmitted via contact with contaminated animal urine.
How is Leptospirosis acquired?
How is Leptospirosis acquired?
Direct or indirect contact of skin or mucous membranes with contaminated urine.
What is Leptospira interrogans?
What is Leptospira interrogans?
Gram-negative like bacteria distinguished by their spiral shape.
Key characteristics of Leptospira?
Key characteristics of Leptospira?
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Where does Leptospira survive?
Where does Leptospira survive?
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Leptospira Entry
Leptospira Entry
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Anicteric Leptospirosis
Anicteric Leptospirosis
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Weil's Syndrome
Weil's Syndrome
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Septicemic Phase Symptoms
Septicemic Phase Symptoms
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Weil's Syndrome Manifestations
Weil's Syndrome Manifestations
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MAT Test
MAT Test
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Leptospirosis Lab Findings
Leptospirosis Lab Findings
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Leptospirosis Prevention
Leptospirosis Prevention
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Study Notes
- Leptospirosis is a spirochetal infection acquired by animals and humans
- It is primarily transmitted through direct or indirect contact of skin or mucous membranes with contaminated urine
Etiology
- Leptospira interrogans has 200 serovars
- It is a spirochete, GNB, (LPS) motile
- It is obligate aerobic and slow growing
- It is found in water, soils, and moist organic matter
- Also found in infected urine, parturition tissue
- May survive weeks to months
Pathogenesis
- Entry occurs through cuts, abraded or soft skin
- Can also enter through mucous membranes, conjunctivae
- Inhalation and ingestion can also lead to contracting
- It infects the bloodstream, lymphatics, and organs
- Leads to systemic vasculitis, hemorrhage
- Renal failure (ischemia) possible
- Jaundice may occur due to hepatic cell dysfunction
- Myalgias (necrosis myofibrils, hemorrhage)
- Intrauterine infections are possible
Clinical Manifestations
- Incubation period is 5-30 days
- Anicteric form exists
- Icteric form exists, also known as Weil's syndrome
Septicemic Phase - Anicteric (90%)
- High fever (38-40ºC) is common
- Headache, chills, rigors
- Meningeal irritation
- Abdominal pain, anorexia
- Myalgias, conjunctival suffusion
- Nausea, vomiting, diarrhea
- Cough, pharyngitis, hemoptysis
- Maculopapular rash
Weil's Syndrome - Icteric (10%)
- Hepatic and renal dysfunction
- Hemorrhagic pneumonitis, ARDS
- Cardiac arrhythmia
- Circulatory collapse
- Jaundice appears after the 7th day
- Adrenal hemorrhage may cause sudden death
- Hepatosplenomegaly 25%
- Hypoprothrombinemia
- Increased levels of CPK
- Thrombocytopenia
- Interstitial nephritis
- Congestive heart failure
- Myocarditis
Diagnosis
- Confirmatory tests include MAT microscopic agglutination (Test-acute and convalescence nt serum samples) and PCR
- Urine antigen test is effective 1 week after symptoms
- Pathology can be performed by CDC on formalin fixed samples
- Supportive Tests include testing for IgM
Diagnostic Tests
- Microscopy using Gram stain will not visualize organisms
- Microscopy using Darkfield is intensive and nonspecific
- Direct fluorescent antibody testing is insensitive and unavailable generally
- Blood culture is positive during the first week
- CSF culture is positive during the final or second week
- Serology is positive after the first week
- Microscopic agglutination of urine is sensitive, specific, and positive after the second week, peaking after 5 to 6 weeks, and may persist for months
Laboratories
- Proteinuria
- Pyuria, hematuria
- Increased creatinine
- Increased liver enzymes
- Increased bilirubin < 20mg/dl
- Increased PT
- Increased WBC's, decreased Hgb, decreased plat
- CSF: pleocytosis, normal glucose, mild increased protein
Prevention
- Reduce contact with infected animals, contaminated water, soil, and mud
- Animal vaccine?
- Chemoprophylaxis (95%)
Agents Recommended for Chemoprophylaxis and Treatment
- Chemoprophylaxis: Doxycycline 200mg once a week
- Treatment of mild leptospirosis: Doxycycline 100mg 10 bid, Ampicillin 500-750mg q6h, Amoxicillin 500mg q6h
- Treatment of moderate to severe leptospirosis : Penicillin G 1.5million UIV g6h, Ampicillin 0.5-lg IV q6h
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