Lyme Disease in Knox County

 

 David M. Dubusky, DVM

 

 Definition: Lyme disease is caused by a bacterium known as Borrelia burgdorferi. Lyme disease has been present for decades, but has received more public attention since the late 1980’s. The disease is named for the Connecticut town of Lyme, where the disease is well-known.

 

Prevalence: Until recently, Lyme disease in this part of Ohio has been rare. In 2012, Lyme disease was identified in Coshocton County. In 2013, Lyme disease was identified in Knox County. As of February 2014, there have been 102 positive cases of canine Lyme disease in Ohio. With “tick season” typically April, May and June, that number will undoubtedly rise. Bottom-line, Lyme disease is in Knox County and the threat for both humans and dogs is real.

 

Does Lyme disease affect cats? Despite the common finding of antibodies reactive to B. burgdorferi in cats in endemic areas, natural disease caused by infection in cats—if it occurs at all—is poorly understood. Accordingly, little is known about the prevalence of infection, disease manifestations, and treatment recommendations for feline infections with this agent.

 

Cause: In North America, only Ixodes scapularis and Ixodes pacificus, the eastern and western black-legged (deer) tick, respectively, have been shown to transmit the infection to dogs. Dogs become infected with B. burgdorferi upon inoculation of organisms by tick feeding. Ticks are not able to transmit infection immediately upon first attachment to a host, but instead require a period of approximately 24 to 48 hours of initial feeding before organisms are able to pass across the salivary glands and into the vertebrate host.

 

Clinical Signs: Recurrent acute arthritis associated with painful, swollen joints is commonly seen.  Infected dogs may also be febrile, anorexic, depressed, and may have enlarged lymph nodes.  Although these clinical signs (symptoms) are not specific, recent tick exposure and/or tick feeding make Lyme Disease a more likely diagnosis.  Statistically, 90% of infected dogs are never ill.

 

Diagnosis: We utilize an in-house blood test (4Dx) to screen dogs for four (4) well-known blood parasites; heartworm, Lyme, Ehrlichia and Anaplasmosis. The 4Dx test identifies the dog’s antibody response against Borrelia burgdorferi.  Previous vaccination does not interfere with test results. Regardless of environment and monthly parasite preventatives, we recommend testing all dogs annually for Heartworm, Lyme, Ehrlichia and Anaplasmosis.

 

Treatment: A positive Lyme screening test (4Dx) does not always require treatment. Each case is different. A specific antibody titer is recommended prior to antibiotic therapy (doxycycline x 30 days). Antibiotics may not eliminate a persistent infection, but most dogs respond to therapy, which reduces or may eliminate clinical signs. Prophylactic use of antibiotics following a tick bite is not recommended in dogs given the high frequency of exposure in the face of a relatively low incidence of clinical disease.

 

Control and Prevention: By far, tick control and tick avoidance are the best recommendations. With Lyme disease now in Knox County, one must also consider vaccinating dogs for Lyme disease (Borrelia burgdorferi. The decision to vaccinate against Lyme disease should be based on a risk assessment of the individual dog that includes information about where the dog lives and how often it frequents a tick-infested area. The initial vaccine must be boostered 2-3 weeks later to ensure 12-month protection against the Lyme bacteria.

 

Vaccination against Lyme disease does not replace the need for stringent tick-control programs in pets. Vaccines may not protect against all strains of B. burgdorferi, and ticks harbor multiple pathogens for which vaccines are not yet available. For this reason, Companion Animal Parasite Council (CAPC) recommends that all pets be maintained year-round on highly effective parasite preventatives. Parastar Plus or Preventic collars may be used in conjunction with any monthly parasite preventative (i.e. Trifexis, Sentinel, Heartgard) to kill ticks and prevents tick feeding/engorgement.

 

Attached ticks found on pets should be promptly removed to prevent transmission of B. burgdorferi or any other pathogens they may harbor. To avoid both human exposure and accidental inoculation of pathogens into the pet during the removal process, ticks should be retracted using forceps (tweezers). Care should also be taken to avoid contact with tick contents, ideally by wearing gloves. Careful attention to hand washing following tick removal is also recommended.

 

In summary, the best prevention of Lyme disease involves the following:

1.      Reduce tick exposure and the daily removal of ticks

2.      Parasite prevention…topical tick control

3.      Lyme vaccination

4.      Annual testing (4Dx) to monitor the effectiveness of control/prevention

 

Zoonotic Potential:  Lyme disease also occurs in humans, but is clinically different.  Like dogs, the source of the infection is the black-legged (deer) tick. Reduced exposure and tick control is recommended. Please contact your physician for more information.

 

Please do not hesitate to contact us with any concerns and/or questions regarding Lyme disease or parasite prevention. Thank you!