Lecture 26: Arthropod Borne zoonoses of North America Flashcards
how do insects act as disease vectors
mechanical vectors or biological vectors
what is a mechanical vector
acting merely as a “dirty syringe” going from host to host
what are some examples of mechanical vectors and associated disease
- house flies carrying shigella or salmonella
- fleas carrying yersinia pestis
- deer flies or ticks carrying francisella tularensis
what are biological vectors
important stages of infectious agents lifecycle takes place in insect host
what are some examples of diseases associated with biological vectors
West nile, colorado tick fever, powassan encephalitis, lyme, rift valley fever, RMSF
why are insects effective disease vectors
insects are synathropic, dependet on humans for food and habitat creator
what type of bacteria is RMSF
gram negative coccobacillus
how is RMSF transmitted
dermacentor and ixode ticks
what is a common reservoir for RMSF
rodents
what are symptoms of RMSF
flu like symptoms with rash, vascular damage (can lead to limb amputation)
what are some common symptoms of RMSF in dogs
fever, enlarged LNs, joint inflammation
what are some bacterial arthropod-borne zoonoses
lyme disease, plague, tularemia, rickettsia
what are some viral arthropod -borne zoonoses
west nile, EEE/WEE/VEE, powassan encephalitis, colorado tick fever
what are some parasitic arthropod-borne zoonoses
chagas, babesia, leishmania
what is causative agent of lyme disease
borrelia burgdoferi gram negative spirochete
what is reservoir for lyme disease
rodents
what is mode of transmission for lyme and who is incidental host
mode of transmission: deer ticks
incidental hosts: humans and pets
where is lyme disease most common in U.S.
new england and upper midwest
what are some symptoms of lyme disease
flu-like bulls eye rash, joint pain, fatigue, CNS abnormalities
what disease can cause shifting leg lameness in animals
lyme disease
how long must a tick stay attached/feed to transmit disease
36-48hrs
how to prevent lyme
preventatives and repellents, adequate clothing, remove promptly
what is the causative agent of EEE/WEE
togaviruses
what transmits EEE/WEE to humans and horses
culiseta mosquitoes
what species serves as an amplifying reservoir for EEE/WEE
birds
are people infected with EEE/WEE largely symptomatic or asymptomatic
95% asymptomatic
what is a common symptom of EEE/WEE in horses
neurologic disease
what type of virus is powassan encephalitis
flavivirus-ssRNA virus
what are the reservoirs for powassan encephalitis
mice ad other rodents
how is powassan encephalitis transmitted
deer ticks and groundhog tick (ixodes cookei)
where are most cases of powassan encephalitis in U.S.
new england and upper midwest
what are some symptoms in humans with powassan encephalitis
rare, flu-like +/- encephalitis
what are the symptoms of powassan encephalitis in animals
none noted
who is the incidental host for powassan encephalitis
humans
what type of virus is colorado tick fever
dsRNA virus
what are the reservoirs for colorado tick fever
squirrels, chipmunks and mice
how is colorado tick fever transmitted
rock mountain wood tick (dermacentor andersoni)
where are most cases of colorado tick fever
mountain west extending into western canada
what are some symptoms of colorado tick fever in humans
flu like+/- biphasic fever and rash, rarely CNS symptom
what are some symptoms of colorado tick fever in animals
none noted
who is the incidental host for rocky mountain wood ticks in colorado mountain fever
humans
what is the causative agent of chagas disease
trypanosoma cruzi
who is the reservoir for chagas disease
rodents and small mammals
how is chagas disease transmitted
via “kissing bugs”, triatoma spp
occur when insect defecates on feeding site
where is chagas disease most commonly found
souther states bordering mexico
what are the symptoms of chagas disease in humans
swelling at injection site, fever, fatigue, and rash
what are some symptoms of chagas disease in animals
rodents: asymptomatic
dogs: depression, lethargy
what is a common parasitic zoonoses that can be transmitted via blood and organ transfusions/transplants
chagas disease
how to prevent chagas disease
clean brush and ensure sealed entry points, integrated pest management and insecticides, screen blood and organs
what is the causative agent of babesia
babesia microti
what is the reservoir for babesia
rodents and small mammals
how is babesia transmitted
ticks- ixodes scapularis, typically nymph stage
blood transfusions
what are the symptoms of babesia in animals
rodents: asymptomatic
animals: anemia
