Ixodidae Ticks & Tick-borne Diseases Michael Lehrke

Ixodidae Ticks Ixodidae ticks are hard ticks Taxonomy: Kingdom: Animalia Phylum: Arthropoda Class: Arachnida (Eight legs) Subclass: Acari (Ticks & Mites) Superorder: Parasitiformes (Parasitic ticks) Order: Ixodida Family Ixodidae (Hard ticks) 702 species in 14 genera

Notable Species Amblyomma americanum Dermacentor andersoni The lone star tick Dermacentor andersoni Wood tick Dermacentor variabilis American dog tick Ixodes scapularis (Ixodes dammini) Black-legged deer tick Rhipicephalus sanguineus Brown dog tick

General Morphology Hard scutum or shield, on females it is partial on males it is full A capitulum (mouth parts) that projects from the body Opposed to soft ticks in which the head is beneath the body

A. americanum Morphology Red-brown color, females have white spot posterior to scutum, males have more than one spot around body Mouth parts are particularly long Festoons are present

Dermacentor Morphology Females have a white scutum and brown body, males are brown with white markings (D. variabilis has more white) Eleven festoons Basis capituli is straight Coxae get larger from anterior to posterior

I. scapularis Morphology They have reddish bodies with black scutum, males are usually mostly black Lack of festoons Have anal groove on ventral side, anterior to the anus Adults are “1/2 sesame” sized and nymphs are “poppy seed” sized

R. sanguineus Morphology Brown abdomen and scutum Festoons present Hexagonal basis capituli Coxae remain same size

Morphology

Amblyomma americanum Definitive hosts: Cats, cattle, sheep, goats, horses, rodents, primates Intermediate hosts: Cats, rodents, rabbits It is a three-host tick Southern US and Mexico

Dermacentor andersoni Definitive hosts: Dogs, cattle, sheep, goats, horses, primates, raccoons Intermediate hosts: Rodents, rabbits It is a three-host tick Western North America and Canada

Dermacentor variabilis Definitive hosts: Dogs, cats, cattle, rodents, primates, raccoons Intermediate hosts: Rabbits It is a three-host tick Central and Eastern US

Ixodes scapularis Definitive hosts: Dogs, cats, cattle, rodents, horses, pigs, rabbits, birds, primates Intermediate hosts: Rabbits, rodents, snakes/turtles It is a three-host tick Central, Midwest and Eastern US

Rhipicephalus sanguineus Definitive hosts: Dogs, rodents, rabbits, primates Intermediate hosts: Dogs, rodents, rabbits It is a three-host tick Entire US (your dog is not safe!!)

Life Cycle Three host tick: feeds on three hosts during life cycle Can be all different or the same individual Molt in between feedings Usually winter before each feeding and after molting Progress from Egg -> Larvae -> Nymph -> Adult Larvae, aka rebels, have 6 legs (nymphs keep it real with 8 again)

Life Cycle

Life Cycle

Pathology Usually asymptomatic, like a normal insect bite Tick cuts into skin (can take 10 min to 2 hours to prepare), inserts feeding tube, and secrete anesthetic saliva! (Sucks, literally) Dermacentor and Ixodes have been implicated with tick paralysis Acute, ascending, flaccid motor paralysis, can result in death Thought to be caused by toxins Ticks can transmit diseases!

Treatment/Control Remove the tick, duh DO NOT use ointments/Vaseline or heat, ticks vomit, possibly forcing pathogens into you! Avoid tick infested areas Repellent (DEET)

Tick-borne Diseases Anaplasmosis Babesiosis Ehrlichiosis Lyme disease Rocky Mountain Spotted Fever

Anaplasmosis Formerly human granulocytic ehrlichiosis (HE), now referred to human granulocytic anaplasmosis Caused by bacteria Anaplasma phagocytophilum, transmitted by Ixodes scapularis Symptoms include fever, headache, chills, muscle aches usually 1-2 weeks after bite Diagnosed on symptoms and can be confirmed by lab tests, treated with doxycycline

Babesiosis Caused by blood parasite Babesia microti, transmitted by Ixodes scapularis Usually asymptomatic, can cause flu-like symptoms, dangerous to immunocompromised people Diagnosed with blood smears, visualizing “Maltese-cross” formations, treated, usually clears itself or can be treated with drug combinations

Ehrlichiosis Caused by Ehrlichia species of bacteria, transmitted by lone-star tick Flu-like symptoms, malaise, confusion, rash, red eyes Diagnosed on clinical signs and lab tests, treated with doxycycline

Rocky Mountain Spotted Fever Caused by the bacteria Rickettsia rickettsi, transmitted by Dermacentor variabilis, Dermacentor andersoni, and Rhipicephalus sanguineus Flu-like symptoms, spotted rash, can be deadly if not treated Suspicion, blood tests, platelet count, treated with doxycycline

Lyme Disease NOT “Lyme’s Disease” – Named after Caused by the spirochete bacteria Borrelia burgdorferi, transmitted by Ixodes scapularis Acute: Flu-like symptoms, erythema migrans (bull’s-eye rash), Bell’s palsy, joint pain, fatigue Chronic: Arthritis, neurological issues, persistent fatigue Post-treatment: fatigue, sleep disturbance, cognitive defects, joint problems

Lyme Disease Diagnosed with blood tests (after several weeks), treated with doxycycline, Ceftin, or amoxicillin

Lyme Disease Prevalent on the East Coast and in the Midwest (particularly around this area and Wisconsin) Prevalence is dramatically climbing In 2000 MN had 465 cases, in 2010 that rose to 1293 (270% increase)! In 2000 WI had 631 cases, which rose to 2505 in 2010 (400% increase)!

Lyme Disease

Lyme Disease

Lyme Disease

Prevention These diseases can be prevented by avoiding ticks, using repellents (DEET), and promptly removing ticks

Questions?