Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira. It is transmitted through contact with infected animal urine and can cause a range of symptoms from mild flu-like illness to a severe form known as Weil's disease that involves jaundice, kidney damage, and hemorrhaging. Diagnosis is through microscopic examination of blood or culture but it is difficult to diagnose without laboratory testing. Treatment involves antibiotics but prognosis depends on preventing organ damage and addressing any pulmonary or kidney complications. Prevention requires public health efforts like sanitation as well as avoiding contact with contaminated water or animals.
2. Leptospirosis is a globally important zoonotic
disease caused by spirochetes of the genus
Leptospira
Weil's disease: a severe leptospirosis
characterized by: fever, jaundice, acute renal
injury, refractory shock, and hemorrhage
(especially pulmonary hemorrhage).
The global burden of leptospirosis is hard to quantify because of the
difficulties encountered in its clinical diagnosis and the lack of efficient
confirmatory laboratory testing, which limits public health reporting.
3. leptospirosis
a zoonotic disease
Human-to-human transmission does not occur
sources of transmission to humans: rats, dogs,
cattle, and pigs.
Transmission:
1. indirect contact with contaminated animal
urine through surface waters, moist soil, or
other wet environments
2. direct contact with urine and other excreta
(e.g., products of parturition, placenta) of
infected animals
4. Pathogenesis
• infects the mucosa (conjunctival, oral or tonsillar)
or through macerated, punctured, or abraded skin
• resist innate immune defenses
• Proliferate to bloodstream or extracellularly within
organs
5. Etiologic Agent
Leptospires are difficult to culture from
blood, urine, and (CSF), although certain
species and serovars (e.g., L. interrogans
serovar Copenhageni) are grown more easily
than others.
Rat-associated L. interrogans serovars
Icterohaemorrhagiae and Copenhageni are
mostly commonly associated with Weil's
disease
Incubation period: average: 5–14 days
range: 2–30 days
9. Physical examination
conjunctival suffusion (dilated conjunctival blood
vessels in the absence of discharge)
pharyngeal erythema without exudate
muscle tenderness
rales on lung auscultation or dullness on chest
percussion over areas of pleural hemorrhage
rash (macular, maculopapular, erythematous,
petechial, or ecchymotic)
Jaundice
Meningismus
hypo- or areflexia, particularly in the legs.
10. Phases of Leptospirosis
A. Mild uncomplicated leptospirosis usually ends
in spontaneous resolution within 7–10 days
without sequelae
B. Immune phase:
1. return of fever, headache, other systemic
symptoms after 3–10 days associated with
clearance of leptospires from the blood and the
appearance of antibodies
2. this phase does not respond to antibiotic
therapy
11. C. Weil's disease:
1. characterized by variable combinations of
jaundice, acute kidney injury, hypotension,
and hemorrhage—most commonly the
lungs
2. also affects the git, retroperitoneum,
pericardium, and brain
12. Diagnosis
has been immersed in or has had mucosal or
percutaneous exposure to contaminated animal
urine
Hematologic abnormalities are variable but
common: leukocytosis (typical in severe disease),
leukopenia, hemolytic anemia, mild to moderate
anemia, and thrombocytopenia.
Classic Weil's disease: suggested by elevated
BUN and serum creatinine with mixed
conjugated and unconjugated
hyperbilirubinemia with SGPT elevation to less
than five times the upper limit of normal
13. Definitive DX: presence of the organism by
culture isolation, detection of nucleic acids or
antigen in body fluids, or
immunohistochemical visualization in tissue
Leptospiral cultures do not become positive
for weeks and therefore cannot guide clinical
care.
PCR–based assays have been used in research
laboratories to detect leptospiral DNA
14. Gold standard: microscopic agglutination test
(MAT)—performed only at the CDC
Leptospires can be cultured from blood and
CSF during the first 7–10 days of illness and
urine beginning in the 2nd week
Urine cultures can remain positive for months
or years despite antibiotic therapy
16. Prognosis
Severity of illness: pulmonary and renal
dysfunction is the most important
determinant of prognosis
Advanced age, pulmonary involvement,
elevated serum creatinine, oliguria, and
thrombocytopenia are associated with a poor
prognosis
17. Prevention
No vaccine is available for human
leptospirosis
Prophylaxis: Doxycycline - variably effective
in different settings
Anticipated short-term, well-defined
exposures (military training or specific
adventure travel)-can be considered
Long-term antibiotic prophylaxis has not
been shown to be effective in preventing
infection in high-transmission endemic
settings
18. General sanitation approaches and avoidance
of swimming in potentially contaminated
places are recommended….
Salamat…..