Leptospirosis

What was Lepto previously thought of as?

A "livestock disease" in US, now urban and rural affected (pets)

Who can get Lepto?

All mammals

Treatment for lepto

Antibiotics Supportive care: IV fluids, anti inflammatories (use w/caution), anti-emetics

What serovars are humans susceptible to?

Any serovar

Where in the world could you get Lepto?

Anywhere

How do you avoid getting Lepto?

Avoid contact with urine/floodwater/food/drink

Emergency preparedness biosecurity measures

Avoid flood waters Stores clean water Mitigation plan for exposure situations (PPE, disinfectants)

What factors are influencing the spread of lepto?

Climate change: more/bigger disasters > increases exposures, decreases mitigation factors Urbanization: *rats pee/contaminate water in city Changing human/animal interface: outdoor recreation > *walking dog on leash on beach > contact with marine animals Poverty: underreporting > neglected tropical disease

Risk factors for Lepto in the US

Considered an occupational, outdoor, and recreational zoonosis Risk factors: farmers, vets, miners/sewer workers, abattoir workers, outdoor recreational it's, military personnel, pet/animal owners Globally, health care workers may be at increased risk

Direct contact

Contact with mucous membranes, contaminate open wounds, contact with aerosolized urine droplets Vertical transmission (mostly animals, rare in humans)

How do you get Lepto?

Contaminated water/urine

Serovars of the species borgpetersenii

Hardjo Javanica

Cattle - host adapted serovar and incidental serovars

Hardjo Pomona

Humans are always _______ hosts

Incidental

What is the gold standard for diagnosis

Indirect serum antibody test - need to prove seroconversion - four fold increase in antibodies (Microscopic agglutination test-MAT)

Unique chronic signs for cattle

Infertility, abortion

two species of leptospira

Interrogans Borgpetersenii

Serovar taxonomy

One spices may contain many serogroups and serovars There are over 300 identified serovars > these are divided into 61 serovars Different species may be in the same serovar

Biosecurity prevention measures

PPE - gloves, eye protection Hand washing Management of sick individuals / animals Rodent control Appropriate disposal of collected urine that contains lepto

Host/serovar relationship in the transmission cycle

Pathogen is maintained in the renal tubules and shed in urine It is possible for a host adapted serovar to produce clinical disease in the host

Vaccination for prevention in animals?

Yes Some cross protection - but vaccines do not confer immunity against all serovars For vaccine selection - Need to main serovars that affect each species and local ecology

Rats - host adapted serovar and incidental serovars

icterohaemorrhagiae Grippotyphosa, Autumnalis

Unique chronic signs for dogs

Chronic kidney disease

What animals are affected by lepto?

Can affect all mammals, including wildlife/marine mammals Not well documented in cats *dont really manifest disease Documentation in 'unconventional hosts' is rare

Dogs - host adapted serovar and incidental serovars

Canicola No incidental

Other methods of diagnosis

Canine Leptospira Antibody Test -Used in acute illness (day 4-10) Culture and PCR -from blood (first 7 days) -from CSF (between 4-10 days) -from urine (after day 10)

What taxonomy do we use to classify lepto?

BOTH! PH officials - must understand both classifications > must understand serovars to understand vaccines

What species can lepto cause reproductive issues

Cattle, horses, pigs

Lepto transmission routes

Direct contact with contaminated urine, blood Indirect environmental exposure to contaminated water, soil, food

Pathogenesis of lepto

E-Cadherin > cell adhesion protein is damaged by the bacteria Hepatocellular damage leads to bilirubinemia (yellow color) Vascular endothelial cell damage leads to hemorrhage > petechia

Reservoirs of lepto

Each serovar has different reservoir (maintence) and incidental hosts Humans are always incidental hosts

What are the high risk groups in USA

Occupational: vets, abattoir workers, miners/sewage plant workers Outdoors: foresters, landscapers Recreational: pet owners - dog parks !

Duration of clinical illness in humans

Few days to 3 weeks or more Sequelae may cause lifelong effects

is reporting required in OH?

For animals, voluntary reporting For human cases, reporting is required to the local PH dept. by the close of the next business day (class B)

Spatial and temporal distribution of lepto?

Found everywhere: seasonal variation in temperature climates Tropical climates more affected; no seasonality

Etiologic characteristics of Leptospira spp.

Gram negative spirochete bacteria Double membrane-outer membrane LPS is the main antigen (determines serovar) Aerobic, mobile Can persist in the environment for weeks to months, but needs moisture ! Susceptible to dehydration, heat, common disinfectants

Raccoon - host adapted serovar and incidental serovars

Grippotyphosa Pomona, Autumnalis

Pathogenesis of lepto in incidental hosts

Lepto remains in kidney tubules for a short period of time and is shed in urine for a few days to several weeks

Lepto genus

Leptospira

What is the etiologic agent of Lepto?

Leptospira spp.

How common is lepto?

Leptospirosis is the most common zoonotic disease in the world

Role of reservoir host

Maintains pathogen in the ecosystem

Infection in humans: asymptomatic vs symptomatic

Majority of lepto infections are asymptomatic Of the symptomatic cases > 90% Anicteric form , 10% Icteric form (Weil's disease) Signs are flu like symptoms > leads to underreporting

Indirect transmission

May be ingested, contact with MM, contaminate open wounds, may penetrate skin that has been in prolonged contact with water (controversial)

Role of incidental host

May have symptomatic or asymptomatic infection, will shed pathogen, not required to maintain pathogen

What happens if you get Lepto?

Mostly little to no illness > mostly flu like illness

Vaccination for prevention in humans?

No vaccine for humans

Pigs - host adapted serovar and incidental serovars

Pomona Bratislava, icterohaemorrhagiae

serovars of the species interrogans

Pomona Hardjo Canicola

Deer, Opossum - host adapted serovar and incidental serovars

Pomona No incidental listed

Where do the majority of lepto cases in the US come from?

Puerto Rico, Hawaii Outbreaks seen after heavy rainfall/flooding events

Unique chronic signs for horses

Recurrent uveitis "moon blindness"

Pathogenesis of lepto in maintenance hosts

Remains in renal tubules and is shed in urine and genital fluids in large quantities in persistently infected animals for months to years

Unique chronic signs in pigs

Reproductive losses

Serovar adapted to the host >

Subclinical infection > maintenance host > long term shedding, low antibody titers

Serovar not adapted to the host >

Subclinical infection or clinical disease that leads to death > incidental host > short term shedding, high antibody titers

Synonyms for Lepto?

Weil's syndrome, mud disease, swamp fever, autumn fever, swine herds disease, etc.

Why is diagnosis complicated

Titers can be affected by exposure/vaccination

Leptospira spp. taxonomy system

Two systems, based on DNA and serology Based on WGS 2 clades (pathogenic, saprophytic), 4 subclasses -68 species (>19 pathogenic)

How long before clinical signs develop in humans?

Typically 2 days - 4 weeks