Lecture 4: Leptospirosis

Question 1

Greek meaning for

Lepto + Spira

Answer 1

Thin Spiral

Question 2

Leptospira spp.

Has how many species? Serovars? How many are pathogens?

Answer 2

13 named species with over 250 serovars, 9 are pathogenic

Question 3

Which is the most implicated serovar of Leptospira?

Answer 3

L. interrogans (is more commonly implicated)

Question 4

Describe look of leptospira? How are they visualized?

Answer 4

Thin, tightly coiled spirochetes, with a characteristic hook

Due to their small diameter, they are visualized by darkfield microscopy

Question 5

Leptospira was first described the organisms in renal tubules of a patient who died of __________-

Answer 5

“yellow fever”

Question 6

Leptospira was first isolated where? And was also known as?

Answer 6

Japan

Rice harvest jaundice

Question 7

T/F

Leptospira is endemic throughout the world

Answer 7

True

Peak cases occur during the rainy season in tropical regions and later summer-early fall in temperate regions

Question 8

Which state has the highest incidence of leptospira in the US

Answer 8

Hawaii

128:100,000 cases

Question 9

What are animal vectors of leptospira?

Answer 9

rodents, cattle, swine, dogs, horses, sheep, and goats

Mortality in dogs is about 10%

• Rodents(mice) are hte most important

Question 10

What is the most important vector for leptospira

Answer 10

Rodents (mice)

Question 11

How do rodents pass leptospira?

Answer 11

1. Passed in urine and infects water
2. Organisms remain viable for weeks to months in neutral pH water
3. Rats can shed the organisms in their urine for an extended period of time
4. Rats tend to carry the most virulent strain

Question 12

T/F

Different species of Leptospira have evolved to be passed by a particular host

Answer 12

True

Question 13

Humans are the ________ host for leptospira

Answer 13

incidental

Acquire the bacteria from contaminated environmental sources

Question 14

Portals fo entry for leptospira are

Answer 14

cuts or abraded skin, mucous membranes, or conjunctivae

Controversial if Leptospira species can penetrate intact skin

Question 15

What are the risk factors for leptospira?

Answer 15

1. In the tropics and in poverty (low educaiton, poor housing, contaminated water)
2. Occupational exposures (animal exposures, ranches, farmers, sewer workers”
3. Recreational Activity (freshwater swimming, kayakying)
4. Hosuehold exposure (pet dog, domesticated livestock, rodent infestions)

Question 16

What are the transmission patterns of leptospira?

Epidemic?
Endemic?
Sporadic

Answer 16

Epidemic - monsoons/floodding

Question 17

Describe disease transmission of leptospira

Answer 17

1.

Question 18

What are the transmission patterns of leptospira?

Epidemic?
Endemic?
Sporadic

Answer 18

Epidemic - monsoons/flooding

Endemic - Crowded urban areas

Sporadic - Travelers, jobs exposure

Question 19

Leptospira concentrates in which bodily fluid?

Answer 19

Urine (primary source of infectivity)

Animals get it from water

Question 20

T/F

The spirochete (of leptospira) can live for at least several weeks without a host at room temperature in moist environment or water

Answer 20

True

(Survives well w/o host
Water, warm –> tropical climate increased risk)

Question 21

T/F

Direct or indirect contact with urine can pass leptospira

Answer 21

True

Question 22

T/F

Direct exposure most common

Answer 22

False

Indirect exposure most common

Question 23

T/F

Regarding leptospira clinical awareness on the part of physicians is necessary to care for travelers returning from vacation to endemic areas

Answer 23

True

Question 24

T/F

Leptospirosis is a biphasic illness

Answer 24

True

Question 25

The initial leptospiremic phase lasts _________ days and is characterized by fever.

Answer 25

3–10 Abx therapy is only effective during this phase

Question 26

What phase is abx therapy effective for leptospira

Answer 26

leptospiremic phase lasts 3–10 days

Question 27

Immune phase of leptospira

Answer 27

return of fever, headache, and other systemic symptoms in association with the clearance of leptospires from the blood

Question 28

What phase does leptospira clear the blood

Answer 28

immune phase

Question 29

What is the most common clinical disease for leptospira?

Answer 29

Self-limiting phase

Question 30

Biphasic pattern is associated with __________ fever

Answer 30

Saddle

Question 31

Severe form of leptospira is associated with what disease?

Answer 31

Weil’s disease

Question 32

Describe the initial phase of illness for leptospira?

Answer 32

- Average 1-2 weeks after infection - Occurs during bacteremia - Usually fever with ‘non-specific’ other complaints… muscle aches, abdominal pain, chills, malaise, vomiting

Question 33

Describe the second phase symptoms for leptospira?

Answer 33

1. Eyes (conjunctivitis) 2. Kidneys (Renal failure ....Confusion -> death) 3. Heart (Chest pain, leg swelling, dilated heart) 4. Liver (Jaundice, hepatomegaly)

Question 34

Severity of leptospira is affected by following factors (3)

Answer 34

1. Number of infecting organisms 2. Host’s immune status 3. Virulence of infecting strain

Question 35

Where does leptospira generally stay in the human body

Answer 35

Generally stays outside of human cells, causes intense inflammation in areas it infects: 1. Acute kidney injury with acute tubular necrosis 2. Disrupts hepatocellular adhesion leading to bile stasis 3. Hemorrhage into the lung alveoli 4. Dysregulates coagulation in the blood 5. Causes necrosis of myocytes in the hear

Question 36

T/F Up to 55% of cases of leptospira demonstrate conjunctival suffusion

Answer 36

True This symptom plus fevers is highly suggestive of leptospirosis

Question 37

Severe Clinical Disease of leptospira occurs in what percent of cases? And is also known as what?

Answer 37

Roughly 1% of cases | Known as the Weil Syndrome

Question 38

What is the Weil Syndrome triad?

Answer 38

1. Jaundice 2. Acute kidney injury 3. +/- pulmonary hemorrhage (Renal injury can be so severe as to warrant dialysis)

Question 39

T/F Older dogs affected more than younger dogs by leptospira

Answer 39

False Younger dogs affected more than older dogs )Dogs infected the same way; contact with contaminated water or rat urine)

Question 40

Diagnosis of Leptospira

Answer 40

- High clinical suspicion - No gold standard testing - Serology most frequent test (MAT) (ELISA) - PCR not widely available - Cultures can grow within 10 days if antibiotic was not given (still low success rate)

Question 41

T/F Microscopic agglutination test (MAT) is most frequently used but is imperfect for leptospira

Answer 41

True Serology is most frequently used test

Question 42

Treatment for leptospira

Answer 42

- Doxycycline for very mild disease | - Penicillin or ceftriaxone for moderate – severe disease (Weil’s disease)

Question 43

T/F In practice, if a patient presents with symptoms of leptospirosis, broad spectrum antibiotics will be started.

Answer 43

True

Question 44

A ______________ may occur following antimicrobial therapy for leptospirosis; this is an acute inflammatory response to clearance of spirochetes from the circulation and is characterized clinically by fever, rigors, and hypotension

Answer 44

Jarisch-Herxheimer reaction

Question 45

Prevention of Leptospira

Answer 45

- Avoid swimming in freshwater - Wear protective equipment when coming into contact with animals or wet soil (i.e. gloves) - Boil any catchment or freshwater before drinking - Control rodents and wildlife around home - Vaccinate pets and farm animals - Drain standing water

Question 46

Whats the most common cause of leptospira in hawaii? | Recreational, occupational, habitational

Answer 46

Recreational

Question 47

Leptospirosis in Hawaii is associated with an increase in -_______ farming

Answer 47

taro

Question 48

What is the most common form of leptospira in Hawaii

Answer 48

L. australis most common in Hawaii ( Kauai, the island with the highest annual rainfall and second most rural island, had and continues to have the highest incidence rate, followed by Hawaii, the most rural island)

Question 49

Angiostrongylus cantonensis is found where?

Answer 49

Found worldwide

Question 50

Angiostrongylus cantonensis incidental host are?

Answer 50

Humans

Question 51

Angiostrongylus cantonensis vertebrate reservoir?

Answer 51

Rat

Question 52

Angiostrongylus cantonensis is exposed to humans by ________

Answer 52

slugs (Infective larvae are found in a number of mollusks, including slugs, land snails, and a land planarian; they are also found in a number of unrelated animals, including freshwater prawns, land and coconut crabs, and frogs)

Question 53

Angiostrongylus cantonensis lifecycle

Answer 53

1. The females lay eggs that hatch, yielding first-stage larvae, in the terminal branches of the pulmonary arteries of the rat 2. The first-stage larvae migrate to the pharynx, are swallowed, and passed in the feces 3. They penetrate, or are ingested by, an intermediate host (snail or slug) 4. After two molts, third-stage larvae are produced, which are infective to mammalian hosts. 5. When the mollusk is ingested by the definitive host, the third-stage larvae migrate to the brain where they develop into young adults. 6. The young adults return to the venous system and then the pulmonary arteries where they become sexually mature.

Question 54

Angiostrongylus cantonensis clinical disease

Answer 54

- Some asymptomatic - Most common cause of human eosinophilic meningitis - Ocular invasion occurs. - Eosinophilia is present in most of cases. - Symptoms include headache, stiff neck, fever, rash, pruritus, abdominal pain, constitutional complaints, nausea, and vomiting. - Neurologic involvement varies - In general, the patients do not appear to be as ill as those who have bacterial meningitis.

Question 55

Angiostrongylus cantonensis diagnosis

Answer 55

- Clinical Suspicion is key - The cerebrospinal fluid (CSF) is abnormal (elevated pressure, proteins, and leukocytes; eosinophilia)  - CDC offers a real-time PCR assay for the specific detection of A. cantonensis in human CSF specimens - No good serum serologies

Question 56

T/F There is a good serum serology to diagnoses Angiostrongylus cantonensis

Answer 56

False

Question 57

Angiostrongylus cantonensis Treatment

Answer 57

- Most cases do not require treatment - Supportive care - Conflicting data on anti-helminthic drugs like albendazole Paradoxical worsening -Use of corticosteroids to decrease brain swelling

Question 58

Angiostrongyliasis-Hawaii

Answer 58

- From 2001-2005, there was an outbreak of Angiostrongyliasis in Hawaii on the big island - 18 patients were evaluate - Case-patients were more likely to consume raw homegrown produce in a typical week and to see snails/slugs on produce. - Three patients specifically remember finding a slug in their food/drink.

Question 59

Angiostrongyliasis-Prevention

Answer 59

- don’t eat raw or undercooked snails or slugs - Eating raw or undercooked freshwater shrimp, land crabs and frogs may also result in infection, although, there has not been any documented cases in Hawaii - You should also thoroughly inspect and rinse produce, especially leafy greens, in potable water, and boil snails, freshwater prawns, crabs, and frogs for at least 3–5 minutes. - Eliminating snails, slugs, and rats founds near houses and gardens might also help reduce risk exposure to A. cantonensis.