Tick-Borne Diseases : Tick-Borne Diseases 1 Rickettsia rickettsii
Borrelia burgdorferi What are Ticks? : What are Ticks? Ticks are arachnids.
A lot like spiders and scorpions.
Ticks are very tiny.
About the size of a freckle.
You might not notice one crawling on you!
Young ticks are about the size of a period at the end of sentence. 2 Tick Species in Rocky Mountain Spotted Fever and Lyme disease : Tick Species in Rocky Mountain Spotted Fever and Lyme disease Dermacentor andersoni, Dermacentor variabilis Ixodes scapularis, Ixodes dammini, Ixodes pacificus, Ixodes ricinus Western Black Legged tick, Black Legged tick, European Wood tick, Sheep tick. American dog tick , Rocky Mountain wood tick Rocky Mountain Spotted Fever (RMSF) Lyme Disease 3 RMSF History : RMSF History Reportable disease since the 1920’s
Most fatal of the tick-borne disease
In 2004 alone, 1514 cases were reported.
While in 1998 365 cases were reported. Amitai (2006) 4 Lyme Disease History : Lyme Disease History Documented as early as 1883 by Alfred Buchwald
Identified as arthritis cases among children originally diagnosed as “Lyme Arthritis,”
Named after, Steere et al in 1976
Outbreak in Lyme, Connecticut
In 1981, a bacterial spirochete, Borrelia burgdorferi, found to be the etiologic agent of Lyme disease Gould et al (2008) 5 Epidemiology of RMSF : Epidemiology of RMSF The name implies a disease that one would expect to find prevalent in the Rocky Mountain States.
Only 3% of RMSF cases are reported in the Rocky Mountain States .
35% of the total reported cases are found in North Carolina and Oklahoma.
Reported in all of the contiguous 48 states, except Vermont and Maine.
90% of cases are reported in the months of April through September.
One third of fatal cases of RMSF are reported (Chapman AS, 2006) 6 RMSF Incidence : RMSF Incidence CDC (2008) 7 RMSF Incidence : RMSF Incidence RMsf case/month Rmsf case /year CDC (2008) 8 RMSF IncidenceAge Groups : RMSF IncidenceAge Groups CDC (2008) 9 Epidemiology of Lyme Disease : Epidemiology of Lyme Disease Of the total vector-borne illnesses found in the United States, Lyme disease is by far the most prominent.
It accounts for more than 95% of the vector borne cases of illness in the United States.
19,931 cases in 2006
During 1992--2006, a total of 248,074 cases of Lyme disease were reported to CDC
Lyme disease is most common in children under 15 and adults between 39 and 59 and has no gender preference.
Gould et al (2008) 10 Epidemiology of Lyme Disease Continued : Epidemiology of Lyme Disease Continued High-risk groups include people who work or spend time outdoors such as: farmers, ranchers, scientific researchers, hikers, trail workers, runners, and vacationers.
In the United States, Lyme disease is localized in northeastern, mid-Atlantic and upper north-central states.
Though Lyme has been reported in 49 of the 50 states, there are 12 states in which it is particularly prevalent: Connecticut, Delaware, Rhode Island, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Hampshire, New York, Pennsylvania, and Wisconsin.
In endemic areas the incidence of Lyme Disease is as high as 3%. Gould et al (2008) 11 Lyme Disease Incidence : Lyme Disease Incidence CDC (2008) 12 Lyme Disease Incidence : Lyme Disease Incidence Lyme Cases by month Lyme cases by year CDC (2008) 13 Lyme Disease Incidence : Lyme Disease Incidence Lyme by age Lyme by sex CDC (2008) 14 Lyme Disease Reported By State : Lyme Disease Reported By State CDC (2008) 15 PathologyRocky Mounain Spotted Fever : PathologyRocky Mounain Spotted Fever Rickettsia rickettsii a gram negative bacterium.
Transmitted by American dog tick (Dermacentor variabilis) and Rocky Mountain wood tick (Dermacentor andersoni)
From the portal of entry in the skin, rickettsiae spread via the bloodstream to infect the endothelium and sometimes the vascular smooth muscle cells. 16 (Chapman AS, 2006) Pathology Lyme Disease : Pathology Lyme Disease Bacterium Borrelia burgdorferi transmitted by the tick species, ixodes; Ixodes scapularis, Ixodes pacificus.
Normally lives in mice, squirrels and other small animals.
Tick life-cycle; larvae, nymph, and adult.
Larvae feed on mice, birds, and other small animals
Young tick feeds on an infected animal 17 Gould et al (2008) Tick Life-Cycle : Tick Life-Cycle 18 RMSF Signs and Symptoms : RMSF Signs and Symptoms Fever
Lack of appetite
(Chapman AS, 2006) 19 Diagnosing RMSF : Diagnosing RMSF Diagnosed mainly based on symptoms.
Labs that may help, low white blood cell count, low platelet count, or elevated liver function tests
The incubation period is 2 to 14 days after the tick bite.
Abrupt onset of fever, severe headache, muscle aches, and vomiting.
Rash associated with Rocky Mountain spotted fever usually starts around 4 days into the illness.
Rash is usually the key to diagnosis since not many rashes affect the palms and soles.
Approximately 10% of those infected never get a rash.
7% diagnosed with RMSF die. 20 (Chapman AS, 2006) Lyme Disease Signs/Symptoms : Lyme Disease Signs/Symptoms Circular rash called erythema migrans
Site of a tick bite after a delay of 3-30 days
Loss of muscle tone
Neck stiffness, meningitis
Gould et al (2008) 21 Diagnosing Lyme Disease : Diagnosing Lyme Disease Presenting symptoms primary diagnosis.
Three stages of Lyme disease: early, early disseminated, and late Lyme disease.
A history of a known tick bite.
Most common blood test ordered for Lyme disease is the ELISA. 22 Gould et al (2008) Tick Prevention : Tick Prevention Prevention of RMSF and Lyme disease consists of avoiding known habitats of ticks; woods, tall grasses, brush and animals.
Wearing light colored clothing, long sleeves and pants, closed toed shoes and applying insect spray with DEET.
Frequent inspections while in the tick habitat.
To remove a tick use tweezers, grasping the tick as close to your skin as possible gently pulling straight out then apply a disinfectant.
(Chapman AS, 2006) 23 Before You Hike : Before You Hike 24 Treatment of Lyme Disease and RMSF : Treatment of Lyme Disease and RMSF Drugs of choice (DOC), Doxycycline, for both the adult and child.
No vaccine for RMSF.
1999 ; Smith Kline Beecham receive FDA approval and placed LYMErix vaccine on the market.
2002 ; LYMErix vaccine removed from market, d/t its low demand.
(Chapman AS, 2006) 25 References : References Amitai, A. (2006). Tick-Borne Diseases, Rocky Mountain Spotted Fever. Retrieved September 15, 2009, from http://www.emedicine.com
Cdc. (2008). Tickborne Disease; Rickettsial Disease. Retrieved September 15, 2009, from http://www.cdc.gov/tick/disease
Chapman, A., et al. (2006). Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever, ehrlichioses, and anaplasmosis. Retrieved September 15, 2009, from http://www.guideline.gov
Gould, L., Nelson, R., Griffith, K., Hayes, H., Piesman, J., Mead, P., et al. (2008). Knowledge, attitudes, and Behaviors Regarding Lyme Disease PreventionAmong Conneticut Residents, 1999-2004. Vector-Borne and Zoonotic Diseases, 8(6), 769-776. 26 References : References Harvard Health Publications (2009). Recognizing and avoiding tick-borne illness; most bites won't make you sick, but the ones that do can be serious. Harvard Women's Health Watch, from CINAHL with Full text
Infectious Disease Society of America. (4). Rocky Mountain Spotted Fever on the Upswing. Retrieved September 16, 2009, from http://www.idsociety.org
Wdh. (2007). Rocky Mountain Spotted fever. Retrieved September 15, 2009, from http://www.health.wyo.gov/phsd/epiid/rockymountainspottedfever.html 27