Unit 2 - Ticks and Tick-Related Diseases Flashcards
What are the three families of ticks under the Order Parasitiformes?
Argasidae, Ixodidae, (Nuttalliellidae)
How many legs do insects have?
3 pairs (6)
How many legs do arachnids have?
4 pairs (8)
Do insects have antennae? What about arachnids?
yes; no
Do insects have wings? What about arachnids?
Insects both can and cannot have wings (dependent on species); Arachnids do not have wings
What are some key features for identifying ticks?
anal groove, length of mouthparts, shape of base of mouthparts, and presence of “eyes”
How many legs do tick larva have?
6
How many legs do tick nymphs have?
8
Do adult male ticks have a complete scrotum? females?
Males - yes; Females - no
What’s bacterial agent causes granulocytic anaplasmosis?
Anaplasma phagocytophilum
What tick species are the vectors for granulocytic anaplasmosis?
Ixodes scapularis, I. pacificus
What bacterial agent causes bovine anaplasmosis?
Anaplasma marginale
Which tick species acts as a vector for bovine anaplasmosis?
Dermacentor andersoni
What is the geographical distribution of bovine anaplasmosis?
western U.S. (eastern for biting fly)
What is the bacterial agent that causes Rocky Mountain Spotted Fever?
Rickettsia rickettsii
Which tick species are the vectors for RMSF?
D. variabilis, D. andersoni
What is the geographical distribution of RMSF?
SW U.S.
What is the direct host for H. americanum?
Tick - Amblyomma maculatum (Gulf Coast Tick)
What is the intermediate host for H. american?
Canids
What is the PH for H. americanum?
Rodents, rabbits
List the clinical signs of H. americanum:
- fever
- weakness
- chronic wt. loss
- depression
- muscle atrophy
- pain
- gait abnormalities
- mucopurulent ocular discharge
What is the geographical range for H. americanum?
southern U.S., central and south America
What is the DH for H. canis?
Tick - Rhipicephalus sanguinus (Brown Dog Tick)
What is the IH for H. canis?
canids
What is the PH for H. canis?
rodents
How long PI does it take to see the clinical signs of H. americanum?
4-5 wks PI
What are the clinical signs of H. canis?
mild (fever, lethargy, emaciation), often no symptoms at all
What is the geographical range of H. canis?
old world only
What is the significance of hepatozoonosis?
ingestion of tick vector!
What is the DH for Cytauxzoon felis?
Amblyomma americanum (lone star tick) Dermacentor variabilis (American Dog tick)
What is the IH for Cytauxzoon felis?
felids
What is the reservoir animal for C. felis?
Lynx rufus
What are the clinical signs of C. felis?
lethargy/depression, icterus, high fever, splenomegaly, hepatomegaly
What is the geographical range of C. felis?
SE, South-Central, and Mid-Atlantic U.S.
What are the acute clinical signs of Theileria equi?
fever, inappetence, labored breathing, anemia, jaundice, hemoglobinuria, hemorrhages on conjunctiva, abortion
What are the chronic clinical signs of Theileria equi?
subtle
What is the DH of T. equi?
14 total tick species (Dermacentor, Hyalomma, Rhipicephalus)
What is the IH of T. equi?
equids (REPORTABLE)
Eradicated in the U.S. in the 1980’s until an outbreak occurred in 2008:
Theileria equi
How is babesia transmitted to the host generally?
infected tick transmits sporozoites to vertebrate host via tick saliva
What is the DH for B. canis vogeli?
tick - Rhipicephalus sanguineus (brown dog tick); D. variabilis
What is the geographical range for Babesia canis vogelii?
enzoonotic in U.S., especially south
What is the IH for Babesia gibsoni in the U.S.?
American staffordshire and pit bull terries
What is the DH for B. gibsoni?
tick - R. sanguineus
What are the clinical signs of canine babesiosis?
- can be subclinical
- lethary; fever; anemia –> pallor; jaundice
- splenomegaly
Which is more pathogenic: small babesia or large babesia?
small
What is the DH for Babesia bovis?
R. microplus, R. annulatus
What is the significance of B. bovis in the U.S.?
Eradicated in 1943, Reportable!
What is the IH for B. bovis?
Cattle, other ruminants
What are the clinical signs for B. bovis?
fever, hemolytic anemia, severe multisystemic signs
B caballi has the same DH, IH, and clinical signs as:
Theirleria equi
B bigemina has the same DH, IH, and clinical signs as:
B. bovis
What is the etiology for Lyme?
Borrelia burgdorferi
Which tick species transmit lyme (B. burgdorferi)?
Ixodes scapularis, I. pacificus
What is the geographic distribution for lyme?
- NE to central U.S.
- pacific coast
- less common in southern and midwestern U.S.
What is the etiology for tularemia?
Francisella tularensis
Which tick species transmit tularemia?
D. variabilis, D. andersoni, A. americanum
What is the geographic distribution of tularemia?
Central U.S.
What is the etiology for tropical canine pancytopenia (CME)?
Ehrlichia canis
Which tick species transmit tropical canine pancytopenia?
R. sanguineus, D. variabilis
What is the geographic distribution for tropical canine pancytopenia?
tropics
What is the etiology for canine granulocytic ehrlichiosis?
Ehrlichia ewingii
What tick species transmits canine granulocytic ehrlichiosis?
Amblyomma americanum
What is the etiology for heart water?
Ehrlichia ruminatum
Which tick species transmit heartwater?
Amblyomma spp. where endemic
What is the geographic distribution of heartwater?
sub-Saharan Africa, Caribbean
What is the etiology for canine cyclic thrombocytopenia?
Anaplasma (Ehrlichia) platys
What is the tick species that transmits Canine Cyclic Thrombocytopenia?
R. sanguineus
What is the other name for tick-borne encephalitis?
Powassan encephalitis
What is the vector for tick-borne encephalitis?
Ixodes spp.
What species are clinically affected by tick-borne encephalitis?
humans; domestic animals?
What is the geographic distribution of tick-borne encephalitis?
mainly midwestern, NE U.S., Canada
What is the other name for tick-borne hemorrhagic disease?
Nairobi sheep disease
What is the vector for tick-borne hemorrhagic disease?
various hard tick species
What are the clinical signs of Nairobi sheep disease?
hemorrhagic gastroenteritis in small ruminants
What is the geographic location for tick-borne hemorrhagic disease?
Africa; Asia (FAD)
What is the tick vector for African Swine Fever?
Ornithodoros
What does African swine fever cause?
systemic hemorrhagic disease
What is the asymptomatic reservoir for African swine fever?
warthogs (among others)
What is the geographic distribution of African swine fever?
Africa (Foreign animal disease - FAD)
What species does Colorado tick fever affect?
humans
Etiology of tick bites:
all ticks can cause disease just by their bite (extent may vary)
What is the clinical presentation of tick bites?
- pain and inflammation at site
- possible complications (anemia, 2 inf., “tick worry”)
What is the treatment for tick bite?
manual removal vs. acaricide
What is the prevention method for tick bite?
year-round control
Which tick species are most important in US for tick paralysis?
- Argasid “soft” ticks (e.g. Argas persicus)
- Ixodid “hard” ticks (e.g. D. variabilis, A. maculatum, A. americanum)
What is the pathogenesis of tick paralysis?
acute asccending flaccid paralysis
Mechanical vs. Biological, which is used by tick vectors?
biological (most VBDs)
If a larva gets infected by its first meal, it will always be infected (most likely)
transstadial
Adult female infected either from a previous or first blood meal, she can transmit it to her eggs (vertical)
transovarial
Black-legged tick
Ixodes scapularis
I. scapularis geographic distribution:
Eastern US
Immature I. scapularis host preference:
rodents, birds lizards
Adult I scapularis host preference:
white-tailed deer, livestock
Lone-star tick
Amblyomma americanum
A. americanum geographic distribution:
eastern, central, southern US
A. american host range:
wide host range but prefer white-tailed deer
Gulf Coast Tick
A. maculatum
A. maculatum geographic distribution:
central, eastern, southern US
Immature A. maculatum hosts:
birds, small mammals
adult A. maculatum preferred host:
cattle
American dog tick
D. variabilis
D. variabilis geographic distribution:
central and eastern US; west coast (california)
Immature D. variabilis host:
prefer rodents
Adult D. variabilis host preference:
canine
Rocky Mtn Wood Tick
D. andersoni
D. andersoni geographic distribution:
western US
Immature D. andersoni host preference:
rodents
Adult D. andersoni host preference:
deer, sheep, cattle, etc.
Brown Dog Tick
Rhipicephalus sanguineus
R. sanguineus geographic distribution:
doesn’t like cold…
Host preference for R. sanguineus:
dogs (narrow range)
Cattle Fever Tick
R. annulatus
Name the two tick species eradicated from the US:
R. annulatus, R. microplus
Host preference for R. annulatus:
cattle
Southern Cattle Fever Tick
R. microplus
Host preference for R. microplus:
wide host range
Number of nymphal stages for soft ticks?
greater than or equal to 2
Number of numphal stages for hard ticks?
1
How many times do hard ticks feed?
One-host, single feeding (~1 week)
How many times do hard tick females oviposit?
single, large egg batch
How many times do soft ticks oviposit?
multiple small egg batches
How many times do soft ticks feed?
multiple, quick feedings
Host preference for Argas:
mainly birds and bats
Morphology of Argas:
- leathery cuticle
- flat body margin “suture line”
Host preference for Ornithodoros:
mainly mammals
Morphology of Ornithodoros:
- leathery cuticle
- rounder body margin “no suture line”
Host preference for Otobius megnini:
cattle, horses
Morphology of Otobius megnini:
nymphal tegument, spiny
List the soft tick species:
Argas, Ornithodors, Otobius
List the hard tick species:
Ixodes, Amblyomma, Dermacenter, Rhipicephalus