5.10 Spirochaetales

Question 1

Spirochaetales 4 genera

Answer 1

-Leptospira
-Borrelia
-Treponema: bovine digital dermatitis, ovine footrot
-Brachyspira: swine dysentery

Question 2

physical characteristics of spirochaetales; shape, flagellum, movement, stain

Answer 2

• Slender, helically coiled, spiral organisms
• Wrapped around internalized flagellum
• Move corkscrew, flexing or serpentine
• Don’t stain well with Gram stain
• Use dark field or silver stain

Question 3

what results would we see on a biochem test if we have a leptospirosis infection?

Answer 3

• Elevated creatinine, and blood urea
• Elevated creatine phosphokinase, muscle enzymes
• Elevated bilirubin, alkaline phosphatase
• Bruno has acute renal failure and hepatitis

Question 4

clinical signs of leptospirosis in dogs

Answer 4

-fever
-decreased appetite
-weakness or reluctance to move from pain
-diarrhea
-increased drinking
-jaundice

Question 5

leptospira characteristics; aerobe/anaerobe, shape, special features, growth medium, classification, pathogenicity

Answer 5

• Aerobic spirochetes
• Hooked ends (interrogation mark = interrogans old name)
• Grow in semi-solid rich media 10-14 days (or much longer)
• Dark field, FA, not Gram
• Classification: >60 species, then serovars
• Some species are pathogens, some are non-pathogenic (environmental) and some intermediate

Question 6

why was leptospira previously known as interrogans

Answer 6

it has hooked ends that look like question marks

Question 7

what classifications are there for leptospira hosts? how long does it stay in each and where?

Answer 7

-maintenance hosts: different serovars adapted to animal reservoir
> Characteristically lifetime, kidney (+ genital tract) carriage

-non-maintenance (“accidental” = “incidental”) hosts: a few weeks in kidneys

Question 8

where in the body does leptospira live? how does it leave?

Answer 8

• Home: proximal convoluted tubule of kidney=> shed urine

Question 9

where do leptospira live in the environment?

Answer 9

– Fastidious bacteria
– survive only in wet (moist),
– warm environments 4-6 weeks; “fall fever”, “mud fever”

Question 10

what are environmental sources of infection of leptospira?

Answer 10

contaminated:
-water
-mud
-soil

Question 11

what creatures are resistant to disease caused by leptospira? what animals are susceptible?

Answer 11

resistant:
-rodents
-cats

susceptible:
-dogs
-guinea pigs
-cattle
-horses
-sheep
-humans

Question 12

what animals are chronically colonized with leptospira and commonly contaminate the environment?

Answer 12

rodents; mice, rats

Question 13

peracute signs of leptospirosis infection

Answer 13

DIC, hemorrahages, haemoglobinuria, death

Question 14

acute/ subacte signs of leptospirosis infection

Answer 14

Fever, hepatitis, nephritis, abortion (mastitis)

Question 15

chronic signs of leptospirosis infection

Answer 15

Abortion; chronic nephritis (pig, dog); recurrent uveitis (horses) Infertility pigs, cattle??

Question 16

subclinical signs of leptospirosis infection

Answer 16

Antibody rise only (or mild ‘flu-like illness)

Question 17

leptospira serovars that infect pigs and their symptoms

Answer 17

pomona: Abortion; chronic nephritis

bratislava: small litters, stillbirth, infertility

Question 18

leptospira serovars that infect cattle and their symptoms

Answer 18

pomona: abortion, haemoglobinuria, mastitis

hardjo: abortion, stillborn, weak calves; mastitis

Question 19

leptospira serovars that infect horses and their symptoms

Answer 19

pomona: abortion; recurrent uveitis (periodic ophthalmia)

Question 20

leptospira serovars that infect dogs and their symptoms

Answer 20

canicola: acute or chronic renal failure (interstitial nephritis)

grippotyphosa, pomona: fever, hepatitis, acute renal failure

Question 21

parts of the horse affected most by leptospira

Answer 21

-eyes
-kidneys
-female repro tract

Question 22

how do we diagnose leptospirosis?

Answer 22

-Serology using paired serum samples
> Microscopic Agglutination Test
» Can be hard to interpret

-SNAP test: detect IgM

-PCR: both blood and urine

Question 23

control of leptospirosis

Answer 23

• Vaccines work well
• Vector control

-yearly vaccination can stop cycle

Question 24

treatment for leptospirosis

Answer 24

• Treatment: Doxycycline (2 weeks), ampicillin

Question 25

symptoms of borrelia infection

Answer 25

-dull, depressed, anorexic, dislikes exercise -lameness, swollen joints

Question 26

what bacteria causes lyme disease?

Answer 26

borrelia

Question 27

physical characteristics of borrelia; gram stain, shape

Answer 27

* Gram-negative spiral shape, rods

Question 28

what creature spreads borrelia?

Answer 28

* Arthropod infections (many tick-borne)

Question 29

most significant borrelia organism in canada?

Answer 29

Borrelia burgdorferi most significant in Canada

Question 30

what is the geographical region where borrelia is an issue?

Answer 30

Problem in eastern, central, western US associated with resurgent deer populations (source of food for adult ticks)

Question 31

vector for berrelia burgdorferi

Answer 31

- Ixodes scapularis: (black-legged “deer” tick) in eastern/central USA - Ixodes pacificus in western US, SW British Columbia

Question 32

main host of Borrelia burgdorferi? what is a major source for adult ticks? where?

Answer 32

Main host white-footed mouse, many bird species: persistently bacteremic * Deer major source adult ticks * Populations along north shore lakes Erie and Ontario, dramatic recent increase in Thousand Islands area, spreading

Question 33

life cycle of Ixodes scapularis

Answer 33

1. adult females drop off host to lay eggs 2. eggs hatch into six-legged larvae 3. larvae attach to and feed on first host and may acquire B. burgdorferi 4. larvae molt into nymphs after leaving first host >infected nymphs feed on humans, transmitting B. burgdorferi 5. nymphs attach to and feed on second host and may acquire B. burgdorferi 6. nymphs molt into adults leaving second host >infected adults feed on dogs and sometimes humans, transmitting B. burgdorferi 7. adults attach to the third host for feeding and mating

Question 34

how is borrelia burgdorferi spread to animals and people?

Answer 34

* Spread to animals and people from nymphal and adult tick bite (although adult noticed early and often removed before transmission occurs)

Question 35

signs of Borrelia burgdorferi in people

Answer 35

In people chronic erythematous skin rash (not always!), followed by fever, muscle and joint ache, meningitis * Weeks or months later: -peripheral neuropathy, arthritis, myocarditis

Question 36

symptoms of Borrelia burgdorferi for dogs

Answer 36

* Dogs: fever, anorexia, arthritis; protein-losing glomerulopathy; rarely progressive renal failure

Question 37

symptoms of B. burgdorferi in horses

Answer 37

* Horses: arthritis, uveitis, encephalitis -neuroborreliosis: a rare form of Lyme disease that can present as fever, muscle wasting, difficulty eating, skin sensitivity, and other neurologic signs

Question 38

is lyme disease easy to diagnose in horses?

Answer 38

not easy -clinical signs are often vague and are similar to signs caused by other diseases

Question 39

can an infection of Lyme disease from a horse be passed to other animals?

Answer 39

no, the horse is a dead end host - cannot pass the infection to horses or other animals

Question 40

how do we diagnose and infection of B. burgdorferi?

Answer 40

* Diagnosis: history, clinical signs + serology (SNAP test) Why is PCR not commonly used? * Difficulty diagnosing in endemic areas since subclinical infection (exposure) common

Question 41

can we use PCR to diagnose B. burgdorferi? why?

Answer 41

PCR not commonly used * Difficulty diagnosing in endemic areas since subclinical infection (exposure) common

Question 42

how do we control B. burgdorferi?

Answer 42

Vaccine for dogs in endemic areas (antigenic variants issue, and short-lasting vaccine antibody)

Question 43

What is the habitat of the black legged tick?

Answer 43

wooded, brushy areas