29: SA Ticks

Hard ticks v soft ticks

Hard ticks have dorsally visible mouthparts and scutum, soft ticks have ventrally visible mouthparts and no scutum

Types of hard ticks with short scutum

Females

How do ticks find hosts

Different questing behaviors (passive or active)

Ideal climate for ticks

Mild temps and humid

Most common lifecycle of U.S. small animal ticks

3 host tick

How do ticks find hosts

CO₂

Passive questing behavior

Ticks hang out at the tip of grass

Active questing behavior

They chase you :)

How should you remove a tick

Carefully, with forceps or a tick key, being sure to get the mouthparts

When is a tick bite painful

When you remove the tick

Primary risk associated with tick bites

Vectored pathogens

Additional risks associated with tick bites

• Exsanguination

• Paralysis

• Alpha gal syndrome :(

Tick paralysis

Acute, ascending flaccid motor paralysis

Tick most associated with tick paralysis

Dermacentor spp.

Tick life stages and identifying features

• Egg

• Larva: 6 legs

• Nymph: 8 legs, no genital pore

• Adult: 8 legs, genital pore

Morphologic feature that distinguishes male and female ticks

Complete v incomplete scutum

Morphologic features that can help distinguish tick species

• Mouthparts

• Scutum pattern

• Anal groove location

• Palps and basis capitulum

• Presence of eyes

Tick species that usually start by feeding on reptiles and small rodents

Ixodes scapularis (blacklegged tick) and Ixodes pacificus (deer tick)

Primary diseases vectored by Ixodes spp.

• Borrelia burgdorferi

• Anaplasma phagocytophilum

• Tick paralysis

Tick with predatory questing behaviors

Amblyomma americanum (lone star)

Diseases vectored by Amblyomma americanum

• Ehrlichia

• Rickettsia

• Cytauxzoon

• Tularemia

• Viruses

• Alpha gal syndrome

Larger tick (“big brother”) that has a very painful bite

Amblyomma maculatum (gulf coast)

Diseases vectored by Amblyomma maculatum

• Hepatozooon

• Rickettsia

Tick that reproduces parthogenically

Haemaphysalis longicornis (longhorn tick)

Morphologic features of Haemaphysalis longicornis

Flared second palpal segment and inornate scutum

Primary disease vectored by Haemaphysalis longicornis

Theileria orientalis ikeda

Less interesting Haemaphysalis specie

Haemaphysalis leporispalustris (rabbit tick)

Tick specie that can complete the life cycle indoors

Rhipicephalus sanguineus (brown dog)

Morphologic features of Rhipicephalus sanguineus

Hexagonal basis capitulum

Primary host of Rhipicephalus sanguineus

…dogs

Dermacentor species of interest

Dermacentor variabilis (American dog) and Dermacentor andersoni (Rocky mountain wood tick)

SA soft tick of interest

Otobius megnini (spinose ear tick)

Otobius megnini life cycle

One host, 2 nymphal stages, free living adults

Parasitic stages of Otobius megnini

Larvae and nymphs

Components of integrated tick control

• Repellents

• Prevention

• Behavior management

• Frequent tick checks

Primary ectoparasiticide for ticks

Isoxazolines