Parasitology: Ticks Flashcards
What is the importance of ticks in parasitology?
the can cause:
- bite wounds
- blood loss
- tick paralysis
- transmit disease agents
- threaten the human-animal bond
What is tick paralysis?
a condition associated with some ticks, where the females attach near the spinal cord and release a paralytic agent that affects the host.
What are some tick-borne diseases?
- Lyme borreliosis
- anaplasmosis
- Ehrlichiosis
- Rocky Mountain Spotted Fever
- Cytauxzoonosis
- Babesiosis
- Hepatozoonosis
Why has tick control concern increased recently?
- tick-borne disease issues are becoming more prominent
- several ticks are changing their distribution patterns
What are the two families of ticks?
Ixodidae: the “hard” ticks
Argasidae: the “soft” ticks
Which tick family is more common in western states than eastern states?
Argasidae
Differentiate between hard and soft ticks.
Hard ticks: family Ixodidae. have a shiny, firmer appearance
soft ticks: Family Argasidae, look soft and squashy compared to hard ticks
What is one species of Argasidae that one might see further west? Where are you most apt to find it on a host?
Otobius sp.
the Spinose ear tick (which will be found… in the ears)
What are some defining characteristics of Family Ixodidae?
- the hard ticks
- have a hard, shiny appearance
- mouthparts project forward
- have a scutum on dorsal surface
How does the scutum help determine gender of the adult tick?
Female ticks have a smaller scutum because they cannot afford to be restricted in size because she needs to drink a large amount of blood in order to lay the eggs
What are the life stages of the tick?
egg => larva => nymph => adult
T/F: There is a blood meal between each life stage in ticks.
True
T/F: Ticks will molt between stages.
True
T/F: a tick will stay on their host between stages in the lifecycle.
False, ticks are 3-tick hosts. After each blood meal, they fall off to molt, and then attach to a new host.
Tick infestation is_____ from the environment.
ALWAYS
What is a larval tick called?
a “seed tick”
where do female ticks lay their eggs?
in the environment
how many legs does a larval tick have?
6
If one wanted to most accurately identify a tick, which life stage would they look at?
the adult stage. Species and gender can be determined
T/F: Ticks begin to feed as soon as they get onto a host.
False, ticks can wander around for a bit, plus it takes time to properly attach. During that time, very little feeding occurs
Describe the physical characteristics of the tick nymph.
- 8 legs
- lack a genital opening
At what stage is the genital opening open?
the adult stage
Where do many tick species mate?
on the host
some do mate in the environment
Does the female survive after laying eggs?
nope
What is a hypostome?
a part of the tick located near the head that has barbs on it. Ticks insert the hypostome into the host to attach.
What are some methods that ticks can improve attachment to host?
- can secrete a cementing substance from salivary glands
- can use chelicerae to cut the skin in order to better insert the hypostome
T/F: Ticks feed very early after attachement.
false, feeding is very slow, then increases rapidly as they consume their blood meal before detachment
Describe the process of tick feeding.
Initial period of slow feeding which can last for several days
this is followed by rapid feeding. a period of 12-36 hrs before the tick detaches.
How does the period of feeding vary among ticks?
- larval ticks may be attached for a few days, females may be attached for a week
What are the four major species of ticks covered in this course?
- Dermacentor variabilis: the American Dog Tick
- Rhipicephalus sanguineus: the Brown Dog Tick
- Amblyomma americanum: the Lone Star Tick
- Ixodes scapularis: the Deer tick (aka the black-legged tick)
What is the common name of Dermacentor variabilis?
the American Dog Tick
what is the scientific name of the American Dog Tick?
Dermacentor variabilis
What is the common name of Ixodes scapularis
the Deer tick or the Black-legged tick
What is the scientific name of the Deer Tick
Ixodes scapularis
what is the common name of Amblyomma americanum?
the Lone Star Tick
What is the scientific name of the Lone Star Tick?
Amblyomma americanum
What is the common name of Rhipicephalus sanguineus?
Brown Dog Tick
What is the scientific name of the brown dog tick?
Rhipicephalus sanguineus
T/F: The American Dog Tick is a 3-host tick
true
what hosts do the life stages of Dermacentor variabilis prefer?
larvae- rodents
nymphs: small to medium animals
adults medium to large animals
Describe the physical appearnce of Dermacentor variabilis.
- an ornate tick (there are enamel-like markings on the scutum which differ between males and females)
- short mouth parts
- a square basis capitulum
would you expect a Dermacentor bite to be superficial or deep? why?
a Dermacentor bite would be superficial because it has short mouthparts
What is the typical environment one would expect to see Dermacentor?
grassy meadows, along roadways and trails, young forests
The life cycle length for Dermacentor varies by region. Differentiate.
- 3 month life cycle in the south
- up to 2+ years in the north
What is the general geographic distribution of Dermacentor?
predominantly in Eastern US
T/F: Male Dermacentor can cause tick paralysis in the host.
False. Only females can
What can Dermcentor be a vector for?
- Cytauxzoonosis
- Rocky Mountain Spotted Fever
- Tularemia
- Anaplasmosis (in cattle)
Dermacentor variabilis is the primary vector for which disease? How is it transmitted?
Rocky Mountain Spotted fever
transmitted Transtadially and transovarially
What are the preferred hosts of Ixodes scapularis?
Larvae and nymphs: small mammals, birds (north), lizards (south)
adults prefer deer, large mammals
What is the life cycle of Ixodes scapularis in temperate climates?
2 year, spiral-pattern life cycle.
Which is currently the most commonly seen tick in the Virginia Mountain area?
The Deer Tick
What tick is the smallest of the Big 4?
the Deer Tick
Do Deer ticks have a long or short mouthpart?
long mouthpart, leads to deep bite wounds
What’s a very helpful way to recognize Ixodes?
Look for the anterior anal groove
In what season would you expect to see Ixodes larvae?
late summer and early fall
In what season would you expect to see Ixodes nymphs?
late winter, though they can be present through summer, depending on the region
In what season would you expect to see Ixodes Adults?
active in spring, but can overwinter.
What is the geographical general distribution of Ixodes scapularis?
Eastern, southeastern US
Where do Ixodes typically quest?
Dense woodlands with leaf/fir needle litter. Can also be very common in residential properties
Which is the proposed Ixodes life stage that transmits Lyme Disease to humans?
Nymphs
Which is the proposed Ixodes life stage that transmits Lyme disease to dogs?
adults
What are the diseases of concern that Deer Ticks transfer?
-Lyme Disease
- Anaplasmosis
- Ehrlichiosis
- Babesiosis in humans
- Powassen virus / Deer tick virus
and more
T/F: Lyme Disease prevalence is growing in the region.
True
How do you recognize a female Amblyomma?
they have a white dot on posterior margin of scutum
General appearance of Amblyomma
- Long mouthpart
- males: reddish brown with faint white markings
- Females: trademark white dot on scutum
What hosts do the life stages prefer?
While all prefer deer, all stages are markedly promiscuous feeders
Which sized animals do Amblyomma nymphs and adults typically attach to?
small medium sized mammals
How long is the Amblyomma life cycle in temperate areas?
~2 years
Though it varies by location, when are Amblyomma adults typically seen?
late winter to June
When are Amblyomma larvae seen?
late summer and autumn
When are Amblyomma nymphs seen?
spring and summer
What is the general geographical of Amblyomma in the US?
previously a more southern distribution, now widely distributed in eastern half of US
T/F: We see Lone Star ticks frequently in the Blacksburg area.
False
What is the general questing habitat of Amblyomma?
Woodlands, young second-growth forests, dense underbrush
T/F: newly discovered red meat allergies are induced by lone star tick.
True
T/F: long mouthparts of Amblyomma don’t cause irritation.
False, they totes do
T/F: Large tick populations can completely exsanguinate fauns because how easy it is as a host.
true
What are some known diseases to be transferred by Amblyomma?
- Ehrlichiosis
- Rickettsiois
- Southern Tick-Associated Rash Illness (STARI)
Cytauxzoonosis - Tularemia
- Tick paralysis in North America
Which of the tick species has a hexagonal basis capitulum
Rhipicephalus sanguineus
T/F: Rhipicephalus have no ornamentation.
true
Which size mouth parts do Rhipicephalus have?
shorter
What is the preferred host of Rhipicephalus?
dogs
How long do Rhipicephalus larvae feed?
3-7 days
how long do Rhipicephalus nymphs feed?
4-9 days
how long do Rhipicephalus adults feed?
6-12 days
T/F: males feed and mate only once before dying.
False, males feed and mate intermittenly for several weeks to months
Where do Rhipicephalus adults mate?
on the host
What is the general geographical distribution of the Rhipicephalus?
the Entire US
What is the habitat of Rhipicephalus?
- inside homes and kennels
- yards/gardens when warm
- always around dogs
Ticks are _____ in temperate areas, and ____ in warmer areas.
- seasonal
- year-round
T/F: Rhipicephalus seasonality is obscured by the fact that it can be inside.
True
What are some disease agents that are transmitted by Rhipicephalus?
- Ehrlichiosis
- Anaplasmosis
- Babesiosis
- Rocky Mountain Spotted fever
- Hepatozoonosis
can cause life-threatening anemia when population progress is unchecked
T/F: The cattle tick can transmit Babesia in cattle.
True
What is the scientific name of the tick that causes babesia in cattle?
Rhipicephalus (Boophilus) annulatus
Key points to identifying Ixodes scapularis
- anal groove arches anterior to anus
- long mouth parts
- scutum, mouthparts, and legs are black
Key points to identifying Amblyomma americanum.
- long mouthparts
- white spots on female
- edge of scutum patterned on male
- scutum, mouthparts, and legs reddish brown
key points to identifying Rhipicephalus sanguineus
- short mouthparts
- flared hexagonal basis capitulum
- scutum, mouthparts, and legs solid dark brown
Key points to identifying Dermacentor variabilis
- short mouthparts
- “Lacy” patterned scutum on male and female
- scutum, mouthparts, and legs are reddish brown
