Zoonotic Infections Flashcards
Tick-Borne Relapsing Fever (TBRF)
Borrelia: B. hermsii; B. turacata & B. parkeri, helical shaped, Giemsa stain - spread by Ornithodoros soft ticks and lice
Endemic - western & southwestern USA, virgin islands; somewhat in Africa - Ethiopia and Sudan
flu-like symptoms post tick bite followed by recurrent episodes of fever & chills, can develop into systemic complications
Zoonotic Protozoan Pathogens
Plasmodia
babesia
Trypanosomes - chagas disease, african sleeping sickness
Leishmania
Leishmaniasis
3 forms of the disease – cutaneous, mucocutaneous and visceral (happens after hematogenous spread)
mucocutaneous is the least common
Skin - initial sore after fly bite, appears as a healing scar
Protozoan pathogen
Life cycle two stages - promastigotes with flagella and amastigotes
vector - sand fly
Where does leishmaniasis occur and who is at risk?
90% of all cutaneous forms of disease occur in Afghanistan, Algeria, Brazil, Iran, Iraq, Peru, S. Arabia & Syria (SAND fly)
90% of visceral cases occur in Bangladesh, Brazil, INdia, Nepal, and Sudan
Rarely - Spain and Italy
People who visit these endemic areas are at risk - travelers, volunteers, soldiers, people working outdoors at night.
Risk for infection is highest between dusk and Dawn
Visceral leishmaniasis is opportunistic in HIV patients
How is Leishmaniasis diagnosed?
Giemsa-stained smear of aspirates of tissue specimen and look for intracellular amastigotes
Kinetoplasts (mito DNA) - distinguish Leish. from Histoplasma capsulatum
Can also due a culture and PCR, serology for IgG and get a travel history
Anthrax
Gram-positive rod, elongated and in short chains, Bacillus anthracis
spore forming
3 disease- cutaneous anthrax, GI tract anthrax and inhalation.
cutaneous forms an early papule, can develop into an necrotic eschar (malignant pustule)
Forms several deadly toxins
What are the toxins associated with Anthrax bacteria?
edema factor - raises cAMP levels in host cells
lethal factor - leads to excess production of host cytokines
protective antigen - mediates binding and entry of edema factor and lethal factor into host cells
Inhalation Anthrax
most dangerous form of anthrax infections - after inspiration of 8-50K spores with an incubation period of 1 to 43 days.
bacteria can be found in the blood when the patient becomes ill - will be without spores because the bodies CO2 prevents sporulation
symptoms - sore throat, mild fever, muscle aches, severe difficulty breathing, meningitis and shock
case fatality rate - 80-85%
Plaque
Yersinia pestis - small gram-neg. non-motile rod
endemic - Asia, Europe and NA, transmission is by flea bite or exposure to infected rats
classic - severely swollen and painful lymph nodes, with involvement of organs and esp the lungs - death
Tularemia
Francisella tularensis, small gram-neg rod
transmitted by tick bite or exposure to infected rabbits or other rodents, (deerflys, mosquitoes, fleas) (fleas off house pets)
plague-like illness –ulceroglandulceroglandular
disease (most common) - other forms are oculoglandular, sepsis, typhoidal and pneumonic
Brucellosis (undulant fever) - causes and where
Caused by several different types of Brucella bacteria - small, gram-neg cocco-bacilli
faculative, intracellular pathogens
B. melitensis: goats & sheep
B. abortus: cows
Most common in the middle east but found world wide
Comsumption of non-paxteutized milk and exposure to infected animals
Brucellosis (undulant fever) - presentation
mild to severe +/- suppurative comlications (abscesses)
acute - fever profuse sweating, malaise, headache, muscle and back pain
chronic - chronic fatique, ocular damage, depression and spondylitis
what are the possible bioterrorism agents?
Bacillus anthracis (anthrax)
Yersinia pestis (plague)
F. tularensis (tularemia)
botulinum toxin (botulism)
Coxiella burnetii (Q fever)
smallpox virus
Bacteria as bioterrorism agents - why them?
can be weopanized
widely disseminated
multiple routes of transmission
readily enter the bloodstream
high rates of morbidity and mortality
Can easily cause widespread public panic
Malaria - basics
sub-Sahara Africa, southeast Asia, S. America
acute febrile illness, transmitted by mosquitos
Plasmodia parasites - sporozoites (which transform into merozoites and infect RBC) > severe anemia
RBC - ring-stage trophozoites with Giemsa stain
(1) liver stage (2) blood stage
P. falciparum (life-threatening); & P. vivax (latency)
