Chapter 2: Ecology of tick vectors Flashcards

1
Q

What is one of the first symptoms of lyme disease?

A

erythema migrans — a bulls eye rash that appears
(Only occurs in a percentage of cases — still majority about 70%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the “cargo”?

A

the pathogen or parasite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is zoonoses?

A

diseases transmitted by animal(s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Who is Theobald Smith?

A

Christian scientists who was the first to prove a vector (tick) with protozoan parasite (Bayesian) (Texas cattle fever - 1889)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some common examples of zoonotic diseases?

A
  • lyme disease
  • rocky mounted spotted disease
  • malaria
  • African sleeping sickness
  • Chagas’ disease
  • yellow fever
  • giardiasis
  • babeiosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What disease & its tick causes lyme arthritis?

A
  • borrelia bacteria
  • black legged tick —> lxodes scapularis ticks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How long must a tick be attached to transmit bacteria?

A

4-72 hours (Average=48 hours)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which ticks cause the majority of lyme disease?

A

nymphal ticks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When are nymphal ticks most active?

A

late may-july

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the stages in the parasites life history? How many legs does it have in each stage?

A

egg —> larvae (6-legged) —> nymph (8 legs) —> adult (8 legs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is transovarialt transmission?

A

the transmission of an infectious agent from parent to offspring via infection of the developing egg which subsequently results in infectious adult arthropods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Are male or female ticks larger?

A

Female

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is transstadial transmission?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a niche?

A

an organisms occupation — ticks are recyclers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a habitat?

A

an organisms “address” — high living grass for ticks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is mutualism?

A

2 species living together with mutual benefit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is symbiosis?

A

living together — either mutualism or parasitism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are symptoms of alpha gal syndrome? (caused by lone star ticks saliva)

A
  • red meat allergy
  • hives abdominal cramping
    -life threatening possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are treatments/management for alpha gal syndrome?

A
  • diet change
  • epinephrine
  • antihistamines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the vectors (2) of rocky mountain spotted fever?

A
  1. wood tick —> dermacentor andersoni
  2. dog tick —> dermacentor variabilis
  3. lone star tick —> amblyomma americanum
    * tick vectors remain infected for life
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Is rocky mountain spotted fever a zoonotic disease?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where is Rocky Mountain Spotted Fever the highest?

A

US, Canada, highest incidences in Blue Ridge south-central US

23
Q

How long does it take for the ticks to transfer bacteria of RMSF?

A

4-10 hours

24
Q

Who first discovered & notated RMSF?

A

Howard Ricketts in 1896

25
How many cases of RMSF in the US?
until recently, 300-800 cases in US
26
Which vectors are most common for RMSF?
- most common in US is american dog tick - most common in Virginia is lone star tick
27
Rickettsia rickettsii?
28
What treatments are given for RMSF (antibiotics)
Doxycycline most often given - w/out treatment mortality reaches 20% (HIGH) - w treatment mortality rate is less than 5%
29
What is an amplifying host?
a host in which the level of pathogen can become high enough that a vector such as tick feeds on it and will probably become infectious
30
What is a reservoir host?
a host that can harbor a pathogen indefinitely with no ill effects - a single reservoir host usually primary host of a pathogen
31
What are symptoms of RMSF?
- Early: high fever, headache, myalgia, GI symptoms (quick, acute) - late: rash (all over), photophobia, confusion, ataxia, seizures, cough, dyspnea, arrhythmias, jaundice, severe abdominal pin - long term results: CNS deficits, amputations
32
What symptom does typhus affect?
rectoendothelial symptoms —> severe consequences can lead to death in a few dates - spreads by macrophages - similar to RMSF & can look similar
33
What is lyme disease (bacteria, vector, etc)?
- bacteria: borrelia sp. - vector: “black legged” (deer or seed tick) —> i ixodes scapularis (or ixodes pacificus in west coast) - 500,000 people in US annually
34
When was lyme disease recognized & where? Who identified first?
- Recognized in 1975-76 by Dr. A. Steere - First identified by Dr. Willy Burgdorfer (1981) and Barbour and Benach
35
What are the 3 active stages of tick?
1. larvae 2. nymph 3. adult
36
What are characteristics of the ticks?
does not fly or jump, attatches as host passes by
37
How long is the life cycle of a deer tick?
2 years — only feeds 3 times though
38
What are some hosts of the deer tick?
mice, vole, deer, other mammals (needs host at each of the 3 stages) - white-footed mice are principal resevoir of infection where larval and nymphal ticks feed and become infected with the LD spirochete (lyme)
39
What is the bacteria of lyme?
Borrelia Burgdorferi
40
What primarily causes the variation in the bullseye rash (erythema migrants)?
1. dosage (amount) of borrelia bacteria 2. immune response 3. borrelia variant (ID by PCR DNA)
41
What is the shape of borrelia?
large microaerophilic spirochete
42
How does the borrelia genome differ from other prokaryotes?
genome is linear, not circular, and has numerous copies rather than just 1 (one of the most complex bacteria)
43
What are the stages of lyme disease?
1. primary (First) stage
44
What is the primary stage of lyme? (localized stage)
- Characterized by erythema migrants - rash begins as small red spot @ bite site —> grows - flu/COVID - like symptoms. (malaise, chills, fever, headache, stiff-neck, aches & pains)
45
What is the secondary stage of lyme?
- 2-8 weeks post rash - involve heat & nervous system - electrical conduction to heart impaired (arrhythmias) - nervous system —> can lead to paralysis of facial muscles & impaired concentration
46
How does the Borrelia bacteria get into/move throughout body (pathogenesis)?
1. introduced into skin — bite of infected tick 2. migrate outward in radial fashion 3. causes inflammatory reaction in skin (migration & inflammation — expanding rash) 4. Host immunity initially suppressed (mult. of bacteria) 5. bacteria enters bloodstream and circulates to other parts of the body **bacteria does not cross the placenta
46
What is the tertiary (3rd) stage of lyme?
- within 6 months after rash (slowly disappear over years) - characterized by arthritis (usually large joints — knee) - symptoms develop in 60% of untreated cases - chronic nervous system impairment may occur
47
How do you prevent and treat lyme disease?
- prevention same as RMSF - antibiotics relatively effective in early stage disease - less effective in late disease (bacteria not actively multiplying
48
What is the life cycle of lyme?
look at slide 37
49
Which tick only bites as adult?
american dog tick
50
Which bacteria causes Babesiosis (also deer tick)?
- Babesia - has double ring - can co-infect with borrelia to cause infectious malaria-like illness -Life cycle similar - on the rice in PA and NY
51
What are the hosts for ticks?
- adult ticks lay eggs on white-tailed deer - larval tick feeds on white-footed mouse (attracts disease) - nymphal tick feeds on mouse — then human (bites and transmit disease) (about 1 year)
52
What are Ehrlichiosis and anaplasmosis?
two tick-borne diseases - Ehrlichiosis: common in dogs locally - Anaplasmosis: second most commonly reported tick born disease after lyme
53
What is the toothed hypo stone? What does this implicate?
1. intakes plant juice 2. could have pre-fall implications for originally ingesting plants protein