In this study, we evaluated Amblyomma americanum (lone star tick) in Mississippi for the presence of Ehrlichia chaffeensis, causative agent of human monocytic ehrlichiosis; Ehrlichia ewingii, causative agent of human and canine granulocytic ehrlichiosis; Borrelia lonestari, putative agent of southern tick-associated rash illness; Francisella tularensis, the agent of tularemia; and Rickettsia spp., particularly R. amblyommii, a suspected pathogen. We collected adult A. americanum from four regions of Mississippi: Northeast, Northwest, Southeast, and East. Of the ticks collected, 192 were dissected and DNA was extracted for nested polymerase chain reaction (PCR) assays to detect the above bacteria. In all, 3% of tick extracts had evidence of Borrelia sp., 4% for E. chaffeensis, 6% for E. ewingii, and 44% for a Rickettsia species. As determined by sequencing, most Rickettsia spp. were R. amblyommii. In addition, extracts from 42 pools (total of 950) of larval A. americanum collected in Southwest Mississippi were tested for the presence of E. chaffeensis and Rickettsia species. Of these extracts from pools, nine of 37 (24%) were PCR positive for a Rickettsia sp., most often, R. amblyommii; none had evidence of E. chaffeensis, supporting the ability of lone star ticks to transovarially transmit R. amblyommii, but not E. chaffeensis. This study demonstrates E. chaffeensis, E. ewingii, "B. lonestari", and R. amblyommii in A. americanum by PCR for the first time in Mississippi. Understanding the prevalence and epidemiology of these agents in Mississippi should increase awareness of tick-borne disease in the medical community.

We assessed the impact on populations of non-target mammals of a manually applied 1080 "jam" operation targeting possums (Trichosurus vulpecula) in hilly pastoral land south-west of Dunedin in mid-winter 1991. We found no evidence that mice (Mus musculus) were poisoned, but ferret (Mustela furo) numbers apparently declined immediately after poisoning. The removal of small mammalian predators after a poisoning operation could decrease the immediate predation pressure on native wildlife and rabbits (Oryctolagus cuniculus). Observed decreases in bovine tuberculosis reactor rates in deer and cattle herds after some poisoning operations may therefore result from killing of non-target mammals, especially ferrets, rather than possums.

In this study, we evaluated Amblyomma americanum (lone star tick) in Mississippi for the presence of Ehrlichia chaffeensis, causative agent of human monocytic ehrlichiosis; Ehrlichia ewingii, causative agent of human and canine granulocytic ehrlichiosis; Borrelia lonestari, putative agent of southern tick-associated rash illness; Francisella tularensis, the agent of tularemia; and Rickettsia spp., particularly R. amblyommii, a suspected pathogen. We collected adult A. americanum from four regions of Mississippi: Northeast, Northwest, Southeast, and East. Of the ticks collected, 192 were dissected and DNA was extracted for nested polymerase chain reaction (PCR) assays to detect the above bacteria. In all, 3% of tick extracts had evidence of Borrelia sp., 4% for E. chaffeensis, 6% for E. ewingii, and 44% for a Rickettsia species. As determined by sequencing, most Rickettsia spp. were R. amblyommii. In addition, extracts from 42 pools (total of 950) of larval A. americanum collected in Southwest Mississippi were tested for the presence of E. chaffeensis and Rickettsia species. Of these extracts from pools, nine of 37 (24%) were PCR positive for a Rickettsia sp., most often, R. amblyommii; none had evidence of E. chaffeensis, supporting the ability of lone star ticks to transovarially transmit R. amblyommii, but not E. chaffeensis. This study demonstrates E. chaffeensis, E. ewingii, "B. lonestari", and R. amblyommii in A. americanum by PCR for the first time in Mississippi. Understanding the prevalence and epidemiology of these agents in Mississippi should increase awareness of tick-borne disease in the medical community.