Zoonoses I and II

Question 1

1. Explain the concept of “One Health.”

Answer 1

recognizes that the health of humans is connected to the health of animals and the environment, is an integrative effort of multiple disciplines for collaborations and communication for all aspects of human and animal health

Question 2

2. Define the term zoonosis.

Answer 2

diseases cause by infectious agents that are transmitted between animals and humans or are shared by animals and humans

Question 3

3. Describe the causative species for cat scratch fever?

Answer 3

bartonella species: slightly curbed, gram negative rod bacteria that is slow-growing, motile, oxidase and catalase negative and grow best on chocolate agar

Question 4

3. What is the clinical presentation of Bartonellosis?

Answer 4

papillose and pustules around the cat scratch, a persistent, non healing wound, followed by regional lymphadenopathy (necrotizing granulomatous inflammation and micro abscess formation)

many have fever, headache, most feel generally well

paranoid’s oculoglandular syndrome: inoculation into the conjunctiva
encehpalitis: resolves but can result in seizure or coma

Question 5

3. What are complications infection of immunocompromised with of cat scratch fever?

Answer 5

chronic lesions possible in immunocompromised, can seed the blood stream

bacillary angiomatosis (lobular proliferation of small blood vessels)

peliosis: blood filled cystic lesions of the liver

granulomatous, necrotizing hepatitis and splenitis, endocarditis, osteomyelitis, uveitis, breast abscesses and neurological manifestations

Question 6

How do you confirm diagnosis of bartenellosis?

Answer 6

serologically (IFA, ELISA assays) based on IgG titer or positive IgM, culture/PCR detection)

surgical biopsy and histopathologic analysis of enlarged node

Question 7

How do you treat bartenellosis?

Answer 7

usually do not treat if uncomplicated, not shown to shorten course of disease, azithromycin penetrates lymph nodes and may be effective in accelerating recovery from systemic signs of illness, suppurate nodes drained by needle aspiration

Question 8

Describe the causative organism of plague.

Answer 8

yersina pestis, gram negative bipolar rod, oxidase negative catalase positive, does not ferment lactose, non-motile does not use citrate, erase or indole

Question 9

How is plague transmitted, what are its reservoirs?

Answer 9

primary reservoir is rodents with transmission via fleas; occurs primarily western states (4 corners, CA,OR, NV)

human infection by direct contact with blood, pus from lesions or aerosolized materials from infected animals

can remain viable in cultured blood contaminated soil for at least 24 days

Question 10

Discuss the clinical forms of plague.

Answer 10

Bubonic: high fever, chills, headache, anorexia, malaise after 2-8d with development of swollen lymph nodes (hemorrhagic necrosis)
Septicemic: organism spreads hemotogenously -/+ buboes, can replicate within mononuclear leukocytes, capsules inhibit phagocytosis, shock and DIC can lead to death
Pneumonic: via inhalation of organism or hematogenous spread; cough with hemoptysis and chest pain with bronchopneumonia

Question 11

How do you confirm diagnosis of plague?

Answer 11

can be difficult to diagnose; culture and stain from a node can be done (Wayson or Wrights highlights bipolar appearance), serology can be used

Question 12

How do you treat plague.

Answer 12

streptomycin, gentamicin, tetracylcines or flouroquinolones also effective

Question 13

Which of the zoonoses discussed have a corresponding vaccine?

Answer 13

cat scratch fever: feline vaccine

plague: formalin-inactivated vaccine for travelers
tularemia: live attenuated vaccine available for high risk individuals
leptosporosis: multivalent vaccines used for control in dogs and cattle
brucellosis: RB51 vaccination for calves available; strain 19 vaccine can induce disease in humans)

Question 14

5. Describe the causative agent for tularemia.

Answer 14

Francisella tolerances: gram-negative bipolar rod

Question 15

5. How is tularemia transmitted, what are its natural reservoirs?

Answer 15

direct zoonotic infection of rabbit hunters, wild caught prairie dogs, hamsters, and cats

consuming undercooked gam meats, inhalation of organisms, transmission between animals by ticks and biting flies, organism can also pass tranovarially or directly from ticks to humans

(occurs mostly in the northern hemisphere)

Question 16

What are the clinical presentation(s) of tularemia?

Answer 16

flu-like prodrome followed by symptoms related to the method of infection (ulceroglandular, oropharyngeal, ocular glandular, exudative, pharyngeal, systemic, pneumonic form)

Question 17

How do you confirm diagnosis of tularemia?

Answer 17

notify the lab, tularemia does not grow on routine media, rarely visualized on smear, dx. through serologic methods

Question 18

What is the DOC in treating tularemia?

Answer 18

streptomycin, gentamicin (IM q12, 7-14d); oral chipper, doxy

Question 19

Describe the causative agent for leptospirosis.

Answer 19

Leptospira interrogates: a spirochete with bent or hooked ends, requires specialized media

Question 20

What are common sources of infection and transmission of leptospirosis?

Answer 20

animals are critical to the maintenance of pathogenic leptospires in a given area, organism persists in renal tubules of animals without causing disease (dogs and cattle)

rats are the most common source worldwide, more commonly in US in dogs, and livestock

many cases transmitted by contact with mucosal surface, via aerosolization

disease in humans through direct contact with infected animals or more commonly through exposure to the organism in the environment while working or recreating outdoors (contaminated water); particularly after flooding

Question 21

Who are at particular risk for leptosporosis?

Answer 21

veterinarians (esp. self-sticks) and their staff, farms and slaughterhouse workers, sewer workers, members of the military, zoo-keepers and rice/sugar cane plantation employees

Question 22

What is the clinical presentation of leptosporosis?

Answer 22

Weil’s disease: classic hepatic and renal form of disease, biphasic fever, headache and flu-like illness, followed by hepatomegaly, jaundice and renal insufficiency; jaundice is very common

anicteric disease: presents flu-like but can be followed by a second phase of intense headaches, severe myalgia, abdominal pain, nausea, sometimes a rash, conjunctivitis, conjunctival hemorrhage and important meningitis sequalae

mystery disease: rare manifestation of leptospirosis characterized by “severe pulmonary hemorrhage syndrome”

Question 23

How is leptosporosis diagnosed?

Answer 23

serology with compatible clinical illness, isolation in culture, dark field microscopy

Question 24

How do you treat leptospirosis?

Answer 24

penicillin and related beta-lactam antibiotics and tetracyclines

prophylaxis by avoiding stagnant water, avoid mucosal or abraded skin contact with animal urine–> doxycycline prophylaxis, post exposure penicillin or doxy (Hawaii)

Question 25

Describe the causative agent of brucellosis.

Answer 25

Sp. Brucella, several families: small gram negative cocco-bacillus, facultative intracellular pathogens, virulence via LPS, survives and replicates in leukocytes

Question 26

How is brucellosis transmitted?

Answer 26

from reservoirs of cattle and swine, it can be transmitted via unpasteurized milk and contaminated cheese

today infection is most commonly through skin wounds via contact with placental or vaginal secretions from infected animals (also blood or urine) and aerolization of the organism; can be transmitted via STI or breast milk (think Yellowstone)

Question 27

What is the clinical presentation of brucellosis?

Answer 27

undulant fever, night sweats, headaches, chills, depression, profound weakness, arthralgia, myalgia, GI symptoms, weight loss, orchitis/epididymitis, fetal death/ spontaneous abortion

often lasts for months and can be very debilitating

Question 28

How is brucellosis diagnosed?

Answer 28

based on isolation of the organism, and serology,

Question 29

What is the treatment of brucellosis?

Answer 29

doxy or TMP sulfa in children with rifampin for 6 weeks