Wallace John W, Nicholson William L, Perniciaro Jamie L, Vaughn Meagan F, Funkhouser Sheana, Juliano Jonathan J, Lee Sangmi, Kakumanu Madhavi L, Ponnusamy Loganathan, Apperson Charles S, Meshnick Steven R
1 Department of Epidemiology, University of North Carolina, Gillings School of Global Public Health , Chapel Hill, North Carolina.
2 Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention , Atlanta, Georgia .
Vector Borne Zoonotic Dis. 2016 May;16(5):302-8. doi: 10.1089/vbz.2015.1887. Epub 2016 Mar 23.
Tick-borne diseases cause substantial morbidity throughout the United States, and North Carolina has a high incidence of spotted fever rickettsioses and ehrlichiosis, with sporadic cases of Lyme disease. The occupational risk of tick-borne infections among outdoor workers is high, particularly those working on publicly managed lands. This study identified incident tick-borne infections and examined seroconversion risk factors among a cohort of North Carolina outdoor workers. Workers from the North Carolina State Divisions of Forestry, Parks and Recreation, and Wildlife (n = 159) were followed for 2 years in a randomized controlled trial evaluating the effectiveness of long-lasting permethrin-impregnated clothing. Antibody titers against Rickettsia parkeri, Rickettsia rickettsii, "Rickettsia amblyommii," and Ehrlichia chaffeensis were measured at baseline (n = 130), after 1 year (n = 82), and after 2 years (n = 73). Titers against Borrelia burgdorferi were measured at baseline and after 2 years (n = 90). Baseline seroprevalence, defined as indirect immunofluorescence antibody titers of 1/128 or greater, was R. parkeri (24%), R. rickettsii (19%), "R. amblyommii" (12%), and E. chaffeensis (4%). Incident infection was defined as a fourfold increase in titer over a 1-year period. There were 40 total seroconversions to at least one pathogen, including R. parkeri (n = 19), "R. amblyommii" (n = 14), R. rickettsii (n = 9), and E. chaffeensis (n = 8). There were no subjects whose sera were reactive to B. burgdorferi C6 antigen. Thirty-eight of the 40 incident infections were subclinical. The overall risk of infection by any pathogen during the study period was 0.26, and the risk among the NC Division of Forest Resources workers was 1.73 times that of workers in other divisions (95% confidence interval [CI]: 1.02, 2.92). The risk of infection was lower in subjects wearing permethrin-impregnated clothing, but not significantly (risk ratio = 0.81; 95% CI: 0.47, 1.39). In summary, outdoor workers in North Carolina are at high risk of incident tick-borne infections, most of which appear to be asymptomatic.
蜱传疾病在美国各地造成了大量发病情况，北卡罗来纳州斑点热立克次氏体病和埃立克体病发病率很高，还有莱姆病的散发病例。户外工作者感染蜱传疾病的职业风险很高，尤其是那些在公共管理土地上工作的人。本研究确定了北卡罗来纳州户外工作者队列中的蜱传感染病例，并检查了血清转化的风险因素。在一项评估长效氯菊酯浸渍衣物有效性的随机对照试验中，对来自北卡罗来纳州林业、公园与娱乐及野生动物部门的159名工作人员进行了为期2年的随访。在基线（n = 130）、1年后（n = 82）和2年后（n = 73）测量了针对帕克立克次体、立氏立克次体、“安氏立克次体”和恰菲埃立克体的抗体滴度。在基线和2年后（n = 90）测量了针对伯氏疏螺旋体的抗体滴度。基线血清阳性率定义为间接免疫荧光抗体滴度为1/128或更高，帕克立克次体为24%，立氏立克次体为19%，“安氏立克次体”为12%，恰菲埃立克体为4%。感染病例定义为在1年期间滴度增加四倍。共有40例血清转化为至少一种病原体，包括帕克立克次体（n = 19）、“安氏立克次体”（n = 14）、立氏立克次体（n = 9）和恰菲埃立克体（n = 8）。没有受试者的血清对伯氏疏螺旋体C6抗原呈反应性。40例感染病例中有38例为亚临床感染。研究期间任何病原体感染的总体风险为0.26，北卡罗来纳州森林资源部门工作人员的感染风险是其他部门工作人员的1.73倍（95%置信区间[CI]：1.02，2.92）。穿着氯菊酯浸渍衣物的受试者感染风险较低，但差异不显著（风险比 = 0.81；95% CI：0.47，1.39）。总之，北卡罗来纳州的户外工作者感染蜱传疾病的风险很高，其中大多数似乎没有症状。
