Note on Ehrlichia chaffeensis, Ehrlichia ewingii, and “Borrelia lonestari” infection in lone star ticks (Acari: Ixodidae), Nebraska, USA

The lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), is established in southeastern Nebraska yet the prevalence of tick-associated microorganisms is not known. An initial PCR-based analysis for Ehrlichia chaffeensis, Ehrlichia ewingii, and Borrelia infection in host-seeking adult ticks collected in southeast Nebraska was conducted. A total of 251 adult ticks collected in six sites in southeast Nebraska were tested. E. chaffeensis, E. ewingii, and Borrelia spp. were present, and the prevalence of each was approximately 1.6%. This study demonstrates that Ehrlichia spp. are present in Nebraska lone star tick populations

Population occurrence and pathogen prevalence of lone star (Acari: Ixodidae) ticks collected from southeast Nebraska

Lone star tick, Amblyomma americanum (L.), has recently become established in Nebraska; therefore, local biology, ecology, and tick-borne disease risk are not known. Research was conducted to determine monthly questing activity, establishment, and pathogenic microorganisms associated with the lone star tick in Nebraska. Lone star tick populations were collected from May through August, 2012 in six sites in southeast Nebraska using carbon dioxide (CO2) traps. A total of 747 adults, 3,076 nymphs, and 1,289 larvae were collected. Total ticks collected and monthly activity were significantly different for each site. A semi-randomized sample of 251 adult ticks were selected for polymerase chain reaction (PCR) analysis for Rickettsia spp., Ehrlichia chaffeensis, and E. ewingii. Adult ticks were 51.8% (130/251) positive for Rickettsia spp., and prevalence was almost equal for both sexes 52.1% (73/140) females and 51.4% (57/111) males. Approximately 2% (4/251) of adult ticks tested positive for E. chaffeensis, all from Table Rock Wildlife Management Area where 12% (3/25) of female and 4% (1/25) of males tested positive. Ticks collected in Indian Cave State Park, Schramm SRA, and Table Rock WMA were almost 2% (4/251) positive for E. ewingii, including 2.1% (3/140) female and 0.9% (1/111) male ticks. Co-infection with Rickettsia spp. and E. chaffeensis was detected from 8.0% (2/25) of female and 4.0% (1/25) of male adult ticks from Table Rock Wildlife Management Area. Lone star ticks are established at the six collection sites in southeast Nebraska, and lone star tick-associated disease microorganisms are present in Nebraska. Adviser: Roberto Cortina