Zoonoses I and II Flashcards
- Explain the concept of “One Health.”
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
- Define the term zoonosis.
diseases cause by infectious agents that are transmitted between animals and humans or are shared by animals and humans
- Describe the causative species for cat scratch fever?
bartonella species: slightly curbed, gram negative rod bacteria that is slow-growing, motile, oxidase and catalase negative and grow best on chocolate agar
- What is the clinical presentation of Bartonellosis?
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
- What are complications infection of immunocompromised with of cat scratch fever?
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
How do you confirm diagnosis of bartenellosis?
serologically (IFA, ELISA assays) based on IgG titer or positive IgM, culture/PCR detection)
surgical biopsy and histopathologic analysis of enlarged node
How do you treat bartenellosis?
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
Describe the causative organism of plague.
yersina pestis, gram negative bipolar rod, oxidase negative catalase positive, does not ferment lactose, non-motile does not use citrate, erase or indole
How is plague transmitted, what are its reservoirs?
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
Discuss the clinical forms of plague.
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
How do you confirm diagnosis of plague?
can be difficult to diagnose; culture and stain from a node can be done (Wayson or Wrights highlights bipolar appearance), serology can be used
How do you treat plague.
streptomycin, gentamicin, tetracylcines or flouroquinolones also effective
Which of the zoonoses discussed have a corresponding vaccine?
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)
- Describe the causative agent for tularemia.
Francisella tolerances: gram-negative bipolar rod
- How is tularemia transmitted, what are its natural reservoirs?
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)
What are the clinical presentation(s) of tularemia?
flu-like prodrome followed by symptoms related to the method of infection (ulceroglandular, oropharyngeal, ocular glandular, exudative, pharyngeal, systemic, pneumonic form)
How do you confirm diagnosis of tularemia?
notify the lab, tularemia does not grow on routine media, rarely visualized on smear, dx. through serologic methods
What is the DOC in treating tularemia?
streptomycin, gentamicin (IM q12, 7-14d); oral chipper, doxy
Describe the causative agent for leptospirosis.
Leptospira interrogates: a spirochete with bent or hooked ends, requires specialized media
What are common sources of infection and transmission of leptospirosis?
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
Who are at particular risk for leptosporosis?
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
What is the clinical presentation of leptosporosis?
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”
How is leptosporosis diagnosed?
serology with compatible clinical illness, isolation in culture, dark field microscopy
How do you treat leptospirosis?
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)
Describe the causative agent of brucellosis.
Sp. Brucella, several families: small gram negative cocco-bacillus, facultative intracellular pathogens, virulence via LPS, survives and replicates in leukocytes
How is brucellosis transmitted?
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)
What is the clinical presentation of brucellosis?
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
How is brucellosis diagnosed?
based on isolation of the organism, and serology,
What is the treatment of brucellosis?
doxy or TMP sulfa in children with rifampin for 6 weeks
