1. Leptospirosis

2. Overview
Presumed to be the most widespread zoonosis in the world (WHO 1999)
Also referred to as Weil’s disease as it was first described by Adolf Weil in 1886.
Animals are reservoirs, infections may occur from contact with infected animals, their urine or contaminated water, soil or vegetation.
Infection is often an occupational hazard.

3. Infectious agent Caused by Leptospira interrogans
Thin, highly motile spirochaetes
More than 200 serovars of which there are 23 serogroups
Serovars are antigenically related – high degree of cross-reactivity
In Australia, L. interrogans serovar hardjo is most common in infections of people in contact with animals
In Europe serovars copenhageni and icterohaemorrhagiae (carried by rats) are usually responsible for infection
In SouthEast Asia serovar lai is common

5. Epidemiology Occurrence Reservoir
Worldwide however incidence is highest in tropical regions due to longer survival of leptospires in warm, humid conditions
Disease is seasonal
Temperate regions – peak occurs in summer or fall
Tropical regions – peak occurs during rainy season
Reservoir
Animals (Rodents, dogs, sheep, pigs, cattle)

6. Transmission
Enters body when mucous membranes or abraded skin come in contact with contaminated environmental sources (animal urine, contaminated water, soil or vegetation).
Multiplies in the blood and tissue and can spread to any part of the body but tends to affect the liver and kidney.
Infection is often an occupational hazard.
Recreational activities such as canoeing, hiking and fishing pose a risk also.
1997 US travelers visiting Costa Rica contracted lepto while white-water rafting
1998 athletes who participated in a triathlon in Illinois developed lepto after swimming in a lake.
Eco-Challenge-Sabah 2000 athletes in Malaysia developed lepto most likely from kayaking/swimming in the Segama River.

7. Clinical Notes
Clinical presentation in man is variable making diagnosis difficult
May imitate other diseases e.g. dengue fever and viral haemorrhagic diseases (WHI, ILS)
The majority of infections are subclinical or very mild
Symptoms may recur 7-10 days after initial episode
Infection may be categorized into two forms
Anicteric leptospirosis
Icteric leptospirosis

8. Clinical Notes cont.
Anicteric leptospirosis - mild fever with sudden onset
90% of cases
Headache
Chills
Severe myalgia (calves and thighs)
Skin rash (on occasion)
Icteric leptospirosis – more severe form
Progresses rapidly
Characterised by jaundice. Abdominal pain with diarrhea or constipation, hepatosplenomegaly, nausea, vomiting and anorexia are also seen.
Mortality rate of between 5 and 10% (Heath 1965)
Complications include acute renal failure, pulmonary haemorrhage, respiratory involvement, myocarditis and ocular involvement

9. Clinical Notes cont. Incubation period Treatment 7 - 12 days
Antibiotics beneficial if given in the first 4 days of illness
Penicillin, Doxycycline, Cephalosporins, Erythromycin

10. Differential diagnosis
Investigate the possibility of the following:
Influenza
Dengue fever
Malaria
Typhoid
Other disease that may mimic leptospirosis include
Encephalitis
Poliomyelitis
Rickettsiosis
Glandular fever
Brucellosis
Malaria
Viral hepatitis
Pneumonitis

11. Dengue & lepto misdiagnosis
Differentiation on clinical grounds between dengue and leptospirosis may be impossible during the early stages of the illness (Levett et al 2000)
Levett at al (2000) found a large proportion diagnosed with leptospirosis actually had dengue and vice versa.
Dual infections may also occur (Levett et al 2000)
The characteristic rash of dengue may be the only distinguishing feature
An outbreak of an undifferentiated fever in India (2000) was thought to be a “viral” or “dengue-like” illness.
Investigation by Karande et al found that at least 1/3 had leptospirosis.

12. Antibody Response Immunity to specific serovar after infection.
Antibodies from an infection with a particular serovar do not necessarily protect against infection with other serovars (WHO, ILS)
IgM antibody
detectable from 2nd day of infection and usually occurs in all patients
IgM antibody may persist for several months
IgG antibody
rises for days after onset of symptoms
IgG antibody may not occur in all patients

13. Diagnosis Diagnostic Aids Isolation
Microscopic Agglutination Test (MAT)
Dip-S-Tick
IgM ELISA

14. Isolation
Transitory bacterial shedding, although may be present up to 7-10 days after onset of symptoms in blood and CSF.
May be isolated from urine from 7-30 days.
Organism is fastidious in its growth requirements.
Culture difficult to perform and can take 6-8 weeks to obtain isolates.

15. Microscopic Agglutination Test
Abbreviation = MAT
IgM antibody is the major antibody detected by MAT
Antibodies may not be detectable for up to 21 days
Requires maintenance of live pathogenic leptospires
Subjective interpretation – best results with highly skilled personnel
Requires paired sera for optimal results
Recent studies suggest that the MAT is less sensitive than the ELISA (Levett et al, 2001)

16. Panbio leptospirosis products
Panbio Leptospira IgM Dip-S-Tick
USA-FDA Cleared
Simple to use – no specialised equipment required
Ideal for small volume testing
Visual reading
Built in control well
Detects positives earlier than MAT
Detects antibodies to a broad range of serovars
Panbio Leptospira IgM ELISA
Indirect ELISA
IgM ELISA only, as IgG antibodies not always produced.
Diagnosis using one serum sample only
Fast - 1hr 10min assay time

17. Panbio leptospirosis products
High sensitivity and specificity demonstrated by independent studies

18. Panbio Leptospirosis IgM ELISA
Specific serum antibodies combine with leptospirosis
antigens attached to the polystyrene
surface of the microwells
Washing removes residual serum
Peroxidase-conjugated anti-human specific
immunoglobulin is added
The colourless substrate,
tetramethylbenzidine/hydrogen peroxide (TMB /
H2O2) is hydrolysed to a blue chromogen
Stopping the hydrolytic reaction
with acid turns the TMB yellow
Colour development indicates the presence
leptospirosis antibodies in the test sample

19. Panbio Serological Assays
Offer alternative to culture and MAT
Can facilitate differential diagnosis
Tests to meet demands of either sporadic cases or high throughput screening

20. Please visit the website to see our product range and keep up to date with the progression of the new technologies.