Zoonotic or vector borne diseases II Flashcards
What occupations and activities are at high risk of zoonoses?
Occupations:
Farmer/rancher
Hunter
Veterinarian
Slaughterhouse worker
Activities at risk:
Drinking unpasteurized milk
Swimming
Preparing food
Owning pet
Visitng petting zoo
What does Francisella tularensis cause?
Rabbit Fever
AKA
Tularemia
AKA
Glandular fever
HIGHLY INFECTIOUS!!!!
How is Francisella tularensis transmitted?
Arthropod bite
Break through skin
Exposure to conjunctiva or other mucosal membranes
Aerosol
Ingestion
What are characteristics of Francisella tularensis?
Facultative Intracellular Pathogen
- Small Gram negative coccobacilli
stains poorly - Specific fluorescently-labeld antibody used to ID organism in tissues, sputum, or culture
- Grows inside macrophages
What are the spectrum of diseases encompassed by Tularemia?
Ulceroglandular: Follows primary infection of skin
Oculoglandular: Contaminate eye (conjunctiva) with infected material
Pneumonic: Transmission via aerosol or via secondary spread to the lung
Typhoidal: Ingestion of organism; symptoms similar to typhoid fever
How is tularemia diagnosed?
Serology
Culture - aspirates of bubos, sputum, blood, gastric washings
What are characteristics of Brucellae?
Facultative intracellular parasites of the Reticular endothelial system
Transmitted to humans through infected milk, milk products
or
direct contact with infected animals
What are symtpoms of chronic Brucellosis?
Incubation period: 2-8 weeks
Fever, night sweats, headaches, chills, myalgia, weight loss
Organs of RES often NOT enlarged
What are complications of Brucellosis?
Hepatic lesions
Arthritis
Meningitis
Endocarditis
What is the pathogenesis of Brucellosis?
Enters via mucous membranes, skin, ingested, or inhaled –> engulfed by PMNs and macrophages –> goes to regional lymph nodes –> Multiply within macrophages –> phagocytic cells of the RES
-> Either: STOP
or
Granulomas with recurrent bacteremia
What is the cause of “Classical” Trench Fever?
Bartonella quintana spread by body louse
Reservoir: Humans
Causes Febrile bacteremia in immuno-competent patients
Causes Bacillary angiomatosis and endocarditis in immuno-compromised patients
What is the cause of Carrión’s disease?
Bartonella bacilliformis
1st Phase: Oroya fever (hemolytic anemia)
2nd Phase: Verruga peruana
Reservoir: Human
Vector: Sand fly
What is the cause of Cat Scratch disease?
Bartonella henselae
Reservoir: cats
Causes inflammation in immuno-competent patient
Causes bacillary angiomatosis in immuno-compromised patients
What are characteristics of Rickettsiaceae?
- Obligate intracellular bacteria that are usually transmitted by arthropods
- Fastidious, Gram(-) coccobacilli
- visible in Giemsa stain
- Require host cell for many functions
- Spread from cell-to-cell requires actin polymerization (like shigella and listeria)
What are clinical manifestations of Rickettseae infection?
Skin rash
Fever
Severe headache
malaise
prostration
enlargement of the spleen and liver
Pathogenesis: Vasculitis caused by proliferation of teh organisms in the endothelial lining of small arteries, veins, capillaries. Vascular lesions are prominent in the skin
What causes Rocky Mountain Spotted Fever?
Rickettsia rickettsii
Spread by Dog ticks - passed by full sized tick
Rash of RMSF is similar to measles but is also on palms and soles of feet (where as measles is not)
What causes rickettsial pox?
Rickettsia akara
Mite-borne (rodent –> mite –> human)
Cosmopolitan distribution in US
Rash is more like chickenpox (papulovesicular) with eschar at site of mite bite
What is the cause of epidemic typhus?
Rickettsia prowazekii
Spread by body louse
Not in US - found in places of war (i.e. Somalia)
What is the cause of endemic or murine typhus?
Rickettsia typhi
Disease occurs worldwide (including US)
Flea-borne
Rodent vector
What causes scrub typhus?
Orientia tsutsugamusushi
Mite (chiggers, red mites) borne
Reservoir: rodent
Doesn’t occur naturally in US
What are characteristics of Anaplasma and Ehrlichia?
Obligate intracellular bacteria
Survive in cytoplasmic vacuoles of mammalial hematopoetic cells
(in contrast to Rickettsia and Orientia that live in endothelial cells)
What is the pathogenesis of Anaplasma phagocytophilum?
Primarily infects grnulocytes (neutrophils and rarely eosinophils)
Often referred to as the agent off HGE
Transmitted by Ixodes scapularis (can co-transmit with Lyme disease)
What are characteristics of Ehrlichia chaffeensis (HME)?
Obligate intracellular bacteria that survive in cytoplasmic vacuoles
Morula can be found in cells
Spread by Lone star tick (Amblyomma americanum)
What is the cause of Q fever? Characteristics?
Coxiella burnetii
Humans infected through contact with cattle, goats, sheep
Ticks probably important in animal to animal transmission
Atypical pneumonia as presentation
Rarely, endocarditis
