Leptospirosis is a zoonotic bacterial disease caused by Leptospira interrogans bacteria transmitted from infected animals to humans through contact with water or soil contaminated by animal urine. It has a wide range of clinical manifestations from a mild flu-like illness to potentially fatal Weil's disease affecting the liver and kidneys. High risk groups include agricultural, sewer and military workers exposed to contaminated environments. Diagnosis involves serological tests or culture of the bacteria from blood or urine, with antibiotics like doxycycline used for treatment. Prevention focuses on minimizing exposure through protective equipment or chemoprophylaxis for high risk groups.
2. Leptospirosis
• Leptospirosis is an infectious disease caused by
pathogenic spirochete bacteria of the genus
leptospira that are transmitted directly or
indirectly from animals to human (i.e., a zoonotic
disease).
• Pathogenic leptospires belong to the species
Leptospira interrogans, which is subdivided into
more than 200 serovars with 25 serogroups .
• The leptospiral serovars are naturally carried in
the renal tubules of rodents, wild and domestic
animals.
3. • Leptospirosis is usually
a seasonal disease that
starts at the onset of
the rainy season and
declines as the rainfall
recedes.
• Sporadic cases may
occur throughout the
year with outbreaks
associated with
extreme changing
weather events such as
heavy rainfall and
flooding
5. FACTORS RESPONSIBLE FOR THE
EMERGENCE OF LEPTOSPIROSIS
• a) Reservoir and carrier hosts
• b) Flooding, drainage congestion
• c) Animal-Human Interface
• d) Human host risk factors
6. MODES OF TRANSMISSION
• Contact through skin, mucosa, conjunctiva
• Ingestion of contaminated water
7. HIGH RISK GROUPS
• Workers in the agricultural sectors
• Sewerage workers
• Livestock handlers
• Pet shops workers
• Military personnel
• Search and rescue workers in high risk
environment
• Disaster relief workers (e.g.during floods)
• People involved with outdoor/recreational
activities such as water recreational
activities, jungle trekking, etc.
• Travelers who are not previously exposed to
the bacteria in their environment especially
those travelers and/or participants in jungle
adventure trips or outdoor sport activities
• People with chronic disease and open skin
wounds.
8. CLINICAL MANIFESTATIONS
• The incubation period is usually 10 days, with a range of 2
to 30 days
• The clinical manifestations are highly variable. Typically,
the disease presents in four broad clinical categories
• (i) a mild, influenza-like illness (ILI);
• (ii) Weil's syndrome characterized by jaundice, renal
failure, haemorrhage and myocarditis with arrhythmias;
• (iii) meningitis / meningoencephalitis;
• (iv) pulmonary haemorrhage with respiratory failure.
• DDX: dengue, malaria, typhoid, meliodosis, influenza
9. 1. Clinical case
Acute febrile illness with history of exposure to water and/or environment
possibly contaminated with infected animal urine with ANY of the following
symptoms:
• Headache
• Myalgia particularly associated with the calf muscles and lumbar region
• Arthralgia
• Conjunctival suffusion
• Meningeal irritation
• Anuria or oliguria and/or proteinuria
• Jaundice
• Hemorrhages (from the intestines and lungs)
• Cardiac arrhythmia or failure
• Skin rash
• Gastrointestinal symptoms such as nausea, vomiting, abdominal pain,
diarrhea
11. 3. Confirmed case
• A confirmed case of leptospirosis is a suspected OR probable case with any one of the
following laboratory tests:
• Microscopic Agglutination Test (MAT),
• For single serum specimen - titre ≥1:400
• For paired sera - four fold or greater rise in titre
• Positive PCR (samples should be taken within 10 days of disease onset)
• Positive culture for pathogenic leptospires (blood samples should be taken within 7 days of onset and
urine sample after the 10th
day)
• Demonstration of leptospires in tissues using immunohistochemical staining
(e.g. in post mortem cases)
• In places where the laboratory capacity is not well established, a case can be
considered as confirmed if the result is positive by two (2) different rapid diagnostic tests.
12. Laboratory Diagnosis
• Leptospira MAT
• Leptospira serology IgM antibodies
• Urine for leptospira
• CSF for leptospira
• Tissue for leptospira
15. NOTIFICATION
• For the
purpose of
notification, all
probable and
confirmed
cases must be
notified to the
nearest Health
District Office
within 1 week
of the date of
diagnosis.
16. TREATMENT
• Adults
• Severe cases are usually treated with high doses of IV C-
penicillin (2 M units 6 hourly for 5-7 days). Less severe
cases treated orally with antibiotics such as doxycycline
(2 mg/kg up to 100 mg 12-hourly for 5-7 days),
tetracycline, ampicillin or amoxicillin.
• Third generation cephalosporins, such as ceftriaxone
and cefotaxime, and quinolone antibiotics may also be
effective.
• Jarisch-Herxheimer reactions may occur after the start of
antimicrobial therapy.
• Monitoring and supportive care as appropriate, e.g.
dialysis, mechanical ventilation.
18. PROPHYLAXIS
• Preexposure Prophylaxis:
• Doxycycline 200mg stat dose then weekly throughout the stay
OR
• Azithromycin 500mg stat dose then weekly throughout the stay
(For pregnant women and those who are allergic to Doxycycline)
• Empirical treatment for Post-Exposure:
• Doxycycline 200mg stat dose then followed by 100mg BD for 5
– 7 days for those symptomatic with the first onset of fever.
OR
• Azithromycin 1gm on Day-1, followed by Azithromycin 500mg
daily for 2 days (For pregnant women and those who are allergic
to Doxycycline)
#3: Gram negative organism Leptospira interrogans main types affecting humans are
L. Interrogans icterohaemorrhagie,
Canicola, hardjo and pommona
Need High index of clinical suspicion
#6: The conditions that are favourable for maintenance and transmission of Leptospirosis
are:
a) Reservoir and carrier hosts
Leptospirosis has a very wide range of natural rodent, and non-rodent reservoir
hosts especially rats, cattle, dogs, foxes, rabbits, etc. The animals act as carriers
of the leptospires and excrete large number of leptospires in their urine, thus
responsible for the contamination of large and small water bodies as well as soil.
b) Flooding, drainage congestion
Flooding and drainage congestion may be risk factors for contamination of water
bodies with infected animal urine. Water logged areas may force rodent
population to abandon their burrows and contaminatethe stagnant water by their
urine.
c) Animal-Human Interface
The potential for infection increases through exposure from occupational or
recreational activities without proper protection. Poor cleanliness/sanitation in
recreational areas may attract animal host such as rodent thus increases the risk
of contamination. These may be due to poor maintenance of facilities, improper
disposal of waste and public attitude/ apathy.
d) Human host risk factors
Several sections of the population are more susceptible to infection such as
those not previously exposed to the bacteria in their environment (naïve
immunities), and those with chronic disease and open skin wounds.
#13: Notes on Laboratory Diagnosis
• In cases which needed to be confirmed (hospitalized and suspected death
cases), serum samples should be sent for confirmation by MAT. The MAT is
considered the "gold standard" or cornerstone of serodiagnosis because of its
unsurpassed diagnostic (serovar/serogroup) specificity in comparison with other
currently available tests. Second serum samples must be taken to detect fourfold
or greater rise in titre.
• Simple serological screening method can be done using the rapid test kit for
Leptospira. Reminder: any leptospirosis rapid test kit to be used must be
validated/approved by IMR.
• The ELISA/other rapid tests detect IgM antibodies. The presence of IgM
antibodies may indicate current or recent leptospirosis. A patient’s serum may be
positive 5 to 10 days after onset of symptoms but not usually before this.
Reminder: IgM-class antibodies may remain detectable for several years.
• If the initial sample was taken at an early stage in the infection, the ELISA test
may be positive but MAT negative. Therefore a follow-up sample is required.
Test may be negative if the serogroup of the infecting strain does not react with
the Patoc 1 serovar strain used as the antigen. If antibiotics are given from the
beginning of the illness, the immune and antibody response may be
delayed.
• The diagnosis is also confirmed by isolation of Leptospires from blood (first 7
days) or CSF (days 4-10) during the acute illness, from urine (days ≥7) and from
tissue samples, by using special media. Inoculation of young guinea pigs,
hamsters or gerbils can also be carried out for isolation of leptospires.
Leptospires die quickly in urine. Clean urine sample should be inoculated into
appropriate culture medium not more than 2 hours after voiding. Survival in acid
urine may be increased by making it neutral.
For postmortem diagnosis, in addition to serology and culture, leptospires can be
demonstrated in tissues using PCR or immunohistochemical staining, notably by direct
immunofluorescence.
#14: Figure 1: Leptospiremic phases in conjunction with the laboratory methods of
diagnosis (4).
Note: Biphasic nature of leptospirosis and relevantinvestigations at different stages of
disease. Specimens 1 and 2 for serology are acute-phase specimens, 3 is a
convalescent-phase sample which may facilitate detection of a delayed immune
response, and 4 and 5 are follow-up samples which can provide epidemiological
information, such as the presumptive infecting serogroup (4).
#15: Total WBC maybe normal or high as 50 000 per microliter
Thrombocytopenia is common
Urine may contain bile, protein, casts and red cells
Elevated bilirubin and liver enzymes seen in 75 percent cases
Elevated creatinine in 50%
CSF may show polymorphonuclear of lymphocytic pleocytosis with minimal or moderately elevated protein concentrations and normal glucose
CK elevated in 50% of cases
#17: The Jarisch-Herxheimer reaction is a reaction to endotoxins released by the death of harmful organisms within the body
Presentation
It resembles bacterial sepsis and can occur after initiation of antibacterials, such as penicillin or tetracycline, for the treatment of louse-borne relapsing fever (80-90% of patients) and in tick-borne relapsing fever (30-40%). An association has been found between the release of heat-stable proteins from spirochetes and the reaction. Typically, the death of these bacteria and the associated release of endotoxins or lipoproteins occurs faster than the body can remove the substances. It usually manifests within a few hours of the first dose of antibiotic as fever, chills, rigor, hypotension, headache, tachycardia, hyperventilation, vasodilation with flushing, myalgia (muscle pain), exacerbation of skin lesions and anxiety. The intensity of the reaction indicates the severity of inflammation. Reaction commonly occurs within two hours of drug administration, but is usually self-limiting.
Treatments
Prophylaxis and treatment with an anti-inflammatory agent may stop progression of the reaction. Oral aspirin every four hours for 1–2 days, or 60 mg of prednisone orally or intravenously has been used as an adjunctive treatment[citation needed]. However, steroids are generally of no benefit. Patients must be closely monitored for the potential complications (collapse and shock) and may require i.v. fluids to maintain adequate blood pressure. If available, meptazinol, an opioid antagonist, should be administered to reduce the severity of the reaction. Anti TNF-a may also be effective.[citation needed]
#19: The cost effectiveness and risk versus benefits of antibiotic prophylaxis for
leptospirosis remains unclear. If prophylaxis is considered, the possible options
include:
Pre-exposure Prophylaxis
• May be considered for people at high risk of exposure to potentially contaminated
sources e.g. soldiers going into jungles, rescue team, persons involved in
activities in possible high risk areas e.g. adventurous sports.
• Dose:
Doxycycline 200mg stat dose then weekly throughout the stay
OR
Azithromycin 500mg stat dose then weekly throughout the stay (For pregnant
women and those who are allergic to Doxycycline)
• However the benefit of pre-exposure prophylaxis remains controversial where
possible benefits need to be balanced with potential side effects (e.g. doxycycline
induced photosensitivity, nausea, etc.)
Empirical treatment for Post-Exposure
• In an outbreak, there may be a role for post exposure prophylaxis for those
exposed to a common source as the index case. Dose:
• Doxycycline 200mg stat dose then followed by 100mg BD for 5 – 7 days for
those symptomatic with the first onset of fever.
OR
• Azithromycin 1gm on Day-1, followed by Azithromycin 500mg daily for 2 days
(For pregnant women and those who are allergic to Doxycycline)
Note:
The role of prophylaxis in children has not been adequately studied