Lyme Disease (Borrelia burgdorferi) Rancho Murieta Association Board Meeting August 19, 2014 Kent Fowler, D.V.M. Chief, Animal Health Branch California Department of Food and Agriculture
Panel Members California Department of Food and Agriculture (CDFA) Kent Fowler, DVM Branch Chief, Animal Health Branch (AHB) California Department of Public Health (CDPH) Anne Kjemtrup, DVM, MPVM, PhD Epidemiologist in Vector-Borne Diseases Bryan Jackson, PhD - Associate Public Health Biologist California Department of Fish and Wildlife (CDFW) Ben Gonzales, DVM, MPVM Senior Wildlife Veterinarian Helayna Pera - Environmental Scientist (Wildlife) Brian Patrick - Wildlife Officer CDFW
Discussion Issues Lyme Disease Background Humans Horses Dogs Cause Transmission Symptoms Diagnosis Prevention Vaccination Treatment Rancho Murieta Deer Population Health Deer Population Interaction with RMA residents
A Brief Overview of Lyme Disease In California
California Tick Species 47 species of ticks in California Only 8 species bite humans Ixodid ( hard ) ticks Ixodes pacificus (western black-legged tick) Dermacentor variabilis (American dog tick) Dermacentor occidentalis (Pacific Coast tick) Dermacentor andersoni (wood tick) Rhipicephalus sanguineus (brown dog tick) Argasid ( soft ) ticks Ornithodoros hermsi Ornithodoros parkeri Ornithodoros coriaceus (Pajahuello tick )
Borrelia burgdorferi Lyme Disease Cause of Lyme disease in U.S. * Spirochete bacteria Lyme disease is the most common vector-borne disease in the U.S. In California, western blacklegged tick (Ixodes pacificus) only tick species that transmits LD to people ** * Steere, 2006. Wien Klin Wochenschr. (118): 625-633 ** Lane et al. 2004 J. Med Entomol. (41): 239-248
Early Symptoms of Lyme Disease Non-specific flu-like symptoms Erythema migrans (EM) rash EM rash is slowly expanding rash that sometimes has central clearing Rash typically develops 7-10 days following tick bite (range 1-30 days) Rash is rarely pruritic (Wormser, N Engl J Med 2006;354:2794-801) Reported in about 60% of CA cases EM Rash. Source: Ross Ritter Rash should not be confused with tick-bite lesions (or allergic response)
Neurologic Other Signs of Lyme disease Idiopathic facial palsy (Bell s palsy) Radiculoneuropathy Arthritic Arthritis in one or more joints Cardiac Atrioventricular conduction disturbances, myocarditis, pericarditis
Transmission of B. burgdorferi to humans in California larva female lays eggs Ixodes pacificus Life cycle adult female nymph Larvae or nymphal Ixodes pacificua ticks acquire the bacteria by feeding on infected mammal hosts. People are accidentally infected through the bite of an infected nymph or adult female western blacklegged tick.
Ixodes pacificus--adult habitat Along trail sides, waiting on vegetation, often on the uphill side of a trail Deciduous hardwood forests
Ixodes pacificus: nymphal habitat Leafy under-story in deciduous hardwood forests On fallen logs in hardwood forests Photos courtesy Dr. Robert Lane, UC Berkeley
Adult ticks are found on wild grasses and low plants Ticks do not fall from trees, jump or fly Ticks quest or wait on the ends of grasses for a host to come by and brush against the grass Ticks grasp a host with their forelimbs
California: Ixodes pacificus Infection Prevalence with B. burgdorferi Adult I. pacificus: 1-5% Nymphal I. pacificus: 0-20% In northern CA where studied, (Mendocino, Placer, Yolo Counties), prevalence is often higher in nymphal than adult ticks* I. pacificus larvae: 0% Larvae rarely bite people * Clover and Lane 1995. J. Trop Med Hyg. 53: 237-240; Wright et al 1998. J. Med Ent 35: 1044-1049 From left to right: Adult female, larva (lower), nymph (above), adult male Ixodes pacificus ticks. Source:CADPH
California: Lizards and Lyme Disease Western fence lizard Larval and nymphal I. pacificus ticks feed on lizards. A borreliacidal protein in lizard blood kills Lyme disease spirochetes in the gut of infected I. pacificus nymphs. As a result, in some areas in California, the proportion of infected adult I. pacificus ticks is lower than in the nymphal I. pacificus ticks because the blood meal from the lizard cleaned the tick. Lane and Quistad 1997. J. Parasitol. 84: 29-34; Salkeld and Lane, 2010 Ecology 91 (1): 293-298
About 100 reported cases of Lyme disease per year in California
Reported cases per 100,000 person-years, 2004 2013* Trinity 5.9 Humboldt 4.3 > 5.0 Mendocino 4.0 Sierra 3.1 Nevada 2.4 3.0 4.9 Mono 2.0 Santa Cruz 1.7 Mariposa 1.7 Amador 1.6 1.0 2.9 Sonoma 1.4 Marin 1.0 Others 0.1 0.9 No cases reported *Though Lyme disease cases have been reported in nearly every county, cases are reported based on the county of residence, not necessarily the county of infection. Figure 2. Incidence of Lyme disease, by county, California, 2004-2013
Interactive Lyme Disease Map: www.cdph.ca.gov
www.cdph.ca.gov
Ixodes scapularis tick female nymph Erythema migrans larva male Ixodes pacificus tick
Lyme Disease in Horses Low grade fever Chronic weight loss Sporadic lameness Muscle tenderness Chronically poor performance Arthritis Diverse orthopedic problems Extreme skin hypersensitivity Neurologic signs Uveitis
Lyme Disease in Horses/Dogs Diagnosis Antibody based serologic tests difficult to interpret ELISA, Western Blot, IFA PCR Treatment Doxycycline Oxytetracycline Vaccination No licensed vaccines for horses Three (3) vaccines available for dogs Human vaccine on the market for 4 years (1998-2002) LYMErix by SmithKline Beecham
Lameness/Health Issues in RM Deer Vesicular Stomatitis* Foot and Mouth Disease* Adenovirus Hemorrhagic Disease* Bluetongue* EHD (Epizootic Hemorrhagic Disease)* Malignant Catarrhal Fever* Foot Rot Lyme Disease Injury Copper Deficiency
Issues to Address Concerning Lyme Disease/RM Deer Health Prevalence of lyme disease? Deer ticks species? prevalence + for Lyme Health of deer population? Risk to other livestock/human Possibility to answer these questions with complete workup and necropsy of several deer (4-6) select by lameness/poor health
If we really want to get something done, we ll find a way. If we don t, we ll find an excuse.
Thank You! Kent Fowler, D.V.M. Kent.fowler@cdfa.ca.gov (916) 900-5040 Chief, Animal Health Branch California Department of Food and Agriculture