Ixodidae Ticks & Tick-borne Diseases

1. IxodidaeTicks & Tick-borne Diseases Michael Lehrke

2. 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

3. Notable Species • Amblyomma americanum • 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

4. 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

5. 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

6. 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

7. 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

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

9. Morphology

10. 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

11. 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

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

13. 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

14. 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!!)

15. 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)

16. Life Cycle

17. Life Cycle

18. 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!

19. 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)

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

21. 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

22. 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

23. 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

24. 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

25. 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

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

27. 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)!

28. Lyme Disease

29. Lyme Disease

30. Lyme Disease

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

32. Questions?