Absence of Lyme disease spirochetes in larval progeny of naturally infected Ixodes scapularis (Acari:Ixodidae) fed on dogs

J Med Entomol. 1997 Jan;34(1):52-5. doi: 10.1093/jmedent/34.1.52.


I determined whether transovarial passage of Lyme disease spirochetes occurred more efficiently in Ixodes scapularis Say fed on reservoir-competent dogs. Unlike deerfed ticks, spirochetes are not diminished in dog-fed ticks, and significantly higher transovarial infection rates have been reported for the latter. Females of field-infected I. scapularis (North Salem strain) were used to induce experimental Lyme disease in specific pathogen-free dogs as part of another study. Seventy-four (48 of 65) percent of the females examined were infected with spirochetes, and larvae from infected females were tested for Borrelia burgdorferi within 1 mo of eclosion. No spirochetes were found in 14,700 larvae (225 larvae per female [n = 12] and 750 larvae per female [n = 16]) examined individually by fluorescent antibody (FA) tests or in triturated larval suspensions (approximately 1,500 larvae per female (n = 20]) examined by FA and polymerase chain reaction. Larvae remain an unlikely source of B. burgdorferi infection in the peridomestic setting because transovarial transmission is highly inefficient in I. scapularis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Bacterial / analysis
  • Borrelia burgdorferi Group / genetics
  • Borrelia burgdorferi Group / immunology
  • Borrelia burgdorferi Group / isolation & purification*
  • DNA, Bacterial / analysis
  • Dogs / parasitology
  • Female
  • Flagellin / genetics
  • Fluorescent Antibody Technique, Direct
  • Ixodes / microbiology*
  • Larva
  • Lyme Disease / microbiology*
  • Male


  • Antigens, Bacterial
  • DNA, Bacterial
  • Flagellin