Leptospirosis, Flashcards
What is the prevalence rate of Leptospirosis?
10/100,000 prevalence rate
What is the seasonal peak of leptospirosis?
seasonal with a peak incidence during the
rainy months of July to October
What is the etiology of Leptospirasos that causes pathology?
Leptospira interrogans
◦ Pathogenic strains
What is the nonpathogenic strain of Leptospirosis?
Leptospira biflexa
◦ nonpathogenic strains
thin, coiled spirochetes (0.1 ×
6.0 to 20.0μm)
hook at one or both pointed
ends
Leptospira
The motility of Leptospira sp is by means of
? Motility by means of two
periplasmic flagella
What is the optimum growth of Leptospira?
optimum growth at 28° C to
30° C
Leptospirasos is an obligate aerobes. T or F?
T
How is the sublclinal infection of Leptospirosis?
◦ mild influenza-like febrile illness
What is the severe systemic disease of Leptospirosis?
severe systemic disease (Weil disease)
- *◦ renal and hepatic failure**, extensive
- *vasculitis, myocarditis, and death**
The pathogenesis of Leptospira is determined by?
Determined by:
- *1. Number of infecting organisms
2. host’s immunologic defenses
3. virulence of the infecting strain influence**
MOT of Leptospirosis?
penetrate intact mucous
membranes or skin through small
cuts or abrasions
◦ spread in the blood to all tissues, including
CNS
multiply rapidly and damage the endothelium of
small blood vessels
meningitis, hepatic and renal dysfunction,
hemorrhage
L. interrogans
Where is the early stage of Leptospirosis?
Early Stges
◦ Blood, CSF
Late stage of Leptospirosis?
later stages
◦ Urine
Clearance of Leptospirosis happens when?
Clearance
◦ When humoral activity develops
2 type of host of Leptospirosis?
two types of hosts:
◦ reservoir hosts
Rodents and small
mammals
◦ incidental hosts
dogs, farm animals,
humans
asymptomatic infections
colonize the renal tubules
shed in urine in large numbers
Streams, rivers, standing water, and moist soil can be contaminated with urine from infected animals
◦ organisms surviving for as long as 6 weeks
Reservoir hosts
Most human infections of Leptospirosis
◦ Clinically inapparent
◦ detected only through the demonstration of specific antibodies
Infection of Leptospirosis is introduced through
Infection introduced through skin
abrasions or the conjunctiva
What is the incubation period of Leptospirosis?
Incubation period 1-2 weeks
What are the 2 phases of Leptospirosis?
2 phases:
◦ initial phase
◦ Severe disease
influenza-like illness
◦ fever and myalgia (muscle pain)
Organisms isolated in CSF
remit after 1 week, or the patient may
progress to the second phase
Initial phase
What happens in the second phase of Leptospirosis?
Headache
Myalgia
Chills
abdominal pain
conjunctival suffusion
(i.e., reddening of the
eye)
Can progress to:
◦ vascular collapse
◦ Thrombocytopenia
◦ Hemorrhage
◦ hepatic and renal
dysfunction
acute febrile illness with headache, myalgia (particularly calf muscle) and prostration associated with any of the following symptoms/signs:
◦ Conjunctival suffusion
◦ Anuria or oliguria
◦ Jaundice
◦ Cough,
hemoptysis, and breathlessness
◦ Hemorrhages (intestine, lungs)
◦ Meningeal irritation
◦ Cardiac arryhthmia
◦ Skin rash
The CNS Disease of Leptospirosis is
viral aseptic meningitis
course of the disease is generally
uncomplicated
low mortality rate
Negative CSF culture
Icteric form of generalized
disease
◦ 10% of all symptomatic infections
10% to 15% mortality
Hepatic necrosis not seen
most patients recover full renal function
Icteric disease, or Weil disease
Sudden onset of
◦ Headache
◦ Fever
◦ Myalgias
◦ diffuse rash
Congenital leptospirosis
Laboratory Diagnosis of Leptospirosis
Microscopy ____________________
Gram stain and silver stain ________
Darkfield microscopy ◦ __________
◦ Yields nonspecific findings
Fluorescein-labeled antibody ◦ _____________
- cannot be seen by conventional light microscopy
- not reliable
- relatively insensitive
- used to stain leptospires
◦ Not available in most clinical laboratories
Laboratory Diagnosis:LEptospirosis
Culture
media:
generation time: 6 to 16 hours
28° C to 30° C
Most cultures positive within 2 weeks
Fletcher,
**EMJH [Ellinghausen- McCullough- Johnson-Harris], **
Tween 80-albumin
Leptospirosis is present in the blood for present in blood or CSF
during the first 10 days of
infection
◦ several specimens should be
collected
Leptospirosis is Present in urine after the ____________
first week and for as long as 3 months
Note : ◦ must be treated to neutralize the pH
◦ concentrated by centrifugation
Detected by darkfield microscopy
Laboratory Diagnosis: Leptospirosis
__________
limited success
nucleic acid amplification (e.g., PCR) more sensitive than culture technique is not widely available at this time
Nucleic Acid–Based Tests
Laboratory Diagnosis: Leptospirosis
Antibody Detection ______________
◦ reference method for all serologic tests
◦ measures the ability of the patient’s serum to agglutinate live leptospires
◦ serial dilutions of the patient’s serum are mixed with the test antigens and then examined microscopically for agglutination
◦ Agglutinins appear in the blood of untreated patients after 5 to 7 days of illness
Microscopic agglutination test (MAT)
Treatment, Prevention, and
Control of Leptospirosis?
usually not fatal in the
absence of icteric
disease
Treatment with
penicillin and
doxycycline
◦ Doxycycline for
prevention
vaccination of livestock
and pets has proved
successful in reducing
incidence of disease
Rodent control
