Lecture 26: Arthropod Borne zoonoses of North America

Question 1

how do insects act as disease vectors

Answer 1

mechanical vectors or biological vectors

Question 2

what is a mechanical vector

Answer 2

acting merely as a “dirty syringe” going from host to host

Question 3

what are some examples of mechanical vectors and associated disease

Answer 3

1. house flies carrying shigella or salmonella
2. fleas carrying yersinia pestis
3. deer flies or ticks carrying francisella tularensis

Question 4

what are biological vectors

Answer 4

important stages of infectious agents lifecycle takes place in insect host

Question 5

what are some examples of diseases associated with biological vectors

Answer 5

West nile, colorado tick fever, powassan encephalitis, lyme, rift valley fever, RMSF

Question 6

why are insects effective disease vectors

Answer 6

insects are synathropic, dependet on humans for food and habitat creator

Question 7

what type of bacteria is RMSF

Answer 7

gram negative coccobacillus

Question 8

how is RMSF transmitted

Answer 8

dermacentor and ixode ticks

Question 9

what is a common reservoir for RMSF

Answer 9

rodents

Question 10

what are symptoms of RMSF

Answer 10

flu like symptoms with rash, vascular damage (can lead to limb amputation)

Question 11

what are some common symptoms of RMSF in dogs

Answer 11

fever, enlarged LNs, joint inflammation

Question 12

what are some bacterial arthropod-borne zoonoses

Answer 12

lyme disease, plague, tularemia, rickettsia

Question 13

what are some viral arthropod -borne zoonoses

Answer 13

west nile, EEE/WEE/VEE, powassan encephalitis, colorado tick fever

Question 14

what are some parasitic arthropod-borne zoonoses

Answer 14

chagas, babesia, leishmania

Question 15

what is causative agent of lyme disease

Answer 15

borrelia burgdoferi gram negative spirochete

Question 16

what is reservoir for lyme disease

Answer 16

rodents

Question 17

what is mode of transmission for lyme and who is incidental host

Answer 17

mode of transmission: deer ticks
incidental hosts: humans and pets

Question 18

where is lyme disease most common in U.S.

Answer 18

new england and upper midwest

Question 19

what are some symptoms of lyme disease

Answer 19

flu-like bulls eye rash, joint pain, fatigue, CNS abnormalities

Question 20

what disease can cause shifting leg lameness in animals

Answer 20

lyme disease

Question 21

how long must a tick stay attached/feed to transmit disease

Answer 21

36-48hrs

Question 22

how to prevent lyme

Answer 22

preventatives and repellents, adequate clothing, remove promptly

Question 23

what is the causative agent of EEE/WEE

Answer 23

togaviruses

Question 24

what transmits EEE/WEE to humans and horses

Answer 24

culiseta mosquitoes

Question 25

what species serves as an amplifying reservoir for EEE/WEE

Answer 25

birds

Question 26

are people infected with EEE/WEE largely symptomatic or asymptomatic

Answer 26

95% asymptomatic

Question 27

what is a common symptom of EEE/WEE in horses

Answer 27

neurologic disease

Question 28

what type of virus is powassan encephalitis

Answer 28

flavivirus-ssRNA virus

Question 29

what are the reservoirs for powassan encephalitis

Answer 29

mice ad other rodents

Question 30

how is powassan encephalitis transmitted

Answer 30

deer ticks and groundhog tick (ixodes cookei)

Question 31

where are most cases of powassan encephalitis in U.S.

Answer 31

new england and upper midwest

Question 32

what are some symptoms in humans with powassan encephalitis

Answer 32

rare, flu-like +/- encephalitis

Question 33

what are the symptoms of powassan encephalitis in animals

Answer 33

none noted

Question 34

who is the incidental host for powassan encephalitis

Answer 34

humans

Question 35

what type of virus is colorado tick fever

Answer 35

dsRNA virus

Question 36

what are the reservoirs for colorado tick fever

Answer 36

squirrels, chipmunks and mice

Question 37

how is colorado tick fever transmitted

Answer 37

rock mountain wood tick (dermacentor andersoni)

Question 38

where are most cases of colorado tick fever

Answer 38

mountain west extending into western canada

Question 39

what are some symptoms of colorado tick fever in humans

Answer 39

flu like+/- biphasic fever and rash, rarely CNS symptom

Question 40

what are some symptoms of colorado tick fever in animals

Answer 40

none noted

Question 41

who is the incidental host for rocky mountain wood ticks in colorado mountain fever

Answer 41

humans

Question 42

what is the causative agent of chagas disease

Answer 42

trypanosoma cruzi

Question 43

who is the reservoir for chagas disease

Answer 43

rodents and small mammals

Question 44

how is chagas disease transmitted

Answer 44

via "kissing bugs", triatoma spp occur when insect defecates on feeding site

Question 45

where is chagas disease most commonly found

Answer 45

souther states bordering mexico

Question 46

what are the symptoms of chagas disease in humans

Answer 46

swelling at injection site, fever, fatigue, and rash

Question 47

what are some symptoms of chagas disease in animals

Answer 47

rodents: asymptomatic dogs: depression, lethargy

Question 48

what is a common parasitic zoonoses that can be transmitted via blood and organ transfusions/transplants

Answer 48

chagas disease

Question 49

how to prevent chagas disease

Answer 49

clean brush and ensure sealed entry points, integrated pest management and insecticides, screen blood and organs

Question 50

what is the causative agent of babesia

Answer 50

babesia microti

Question 51

what is the reservoir for babesia

Answer 51

rodents and small mammals

Question 52

how is babesia transmitted

Answer 52

ticks- ixodes scapularis, typically nymph stage blood transfusions

Question 53

what are the symptoms of babesia in animals

Answer 53

rodents: asymptomatic animals: anemia