Canine seroprevalence and the distribution of Ixodes dammini in an area of emerging Lyme disease.

This study evaluates the relative usefulness of canine serosurveys to predict risk of exposure in an area of emerging Lyme disease by comparing the distribution of canine seroprevalence with that of vector ticks. From 16 veterinary clinics throughout the State of Maine, 828 canine sera were obtained during the heartworm-testing months of April and May 1989 and measured for anti-Borrelia antibodies by enzyme-linked immunosorbent assay. In the same year, 1605 ticks, including 585 Ixodes dammini, were collected from pets, humans, small mammals, and deer. Thirty-six dogs were seropositive, 28 of which had not traveled to endemic areas. Eighty-nine percent of all seropositive dogs were from towns within 20 miles (32 km) of the coast; the great majority lived within 5 miles (8 km) of tidewater (odds ratio =4.45, P = .002). Positivity varied from 17% in a southern coastal clinic to 0% in four northern clinics. Of 585 I. dammini identified, all but 5 (99.1%) were also from towns within 20 miles of the coast. Comparison of I. dammini submissions with those of another commonly found tick, Ixodes cookei, corroborated this predominantly coastal distribution. Canine seropositivity generally coincided with this coastal range. These data predicted areas of risk for human Lyme disease, although the prevalence of reported cases remained low.     

Potential for exposure to tick bites in recreational parks in a Lyme disease endemic area.

Eight recreational parks located in a Lyme disease endemic area of southern New York State were surveyed for the presence of ticks during the summer of 1985 by drag sampling. Ixodes dammini, the primary vector of Lyme disease in the northeast, was found in all but one park and accounted for 580 (91.8 per cent) of the 632 ticks collected. Of these, 18 per cent were larvae, 80 per cent were nymphs, and 2 per cent were adults. An I. dammini encounter distance, defined as the mean number of meters traveled before encountering a nymphal or adult I. dammini on a drag cloth, ranged from 36 m in high-risk parks, to infinity (no tick encounters). Generally, areas of high use presented higher encounter distances (lower risk) than those of the entire park. Two of the three parks with the highest annual attendance also had the highest I. dammini population indices as projected from our sampling regimen. These results indicate that recreational parks in Lyme disease endemic areas represent a substantial human risk for tick bites and Lyme disease.     

Borrelia in ticks biting humans and prevention of Lyme borreliosis

We examined by dark field microscopy 195 of 209 Ixodes ricinus ticks that were removed from humans in the Czech Republic (mainly in southern Moravia) during 1997-2001. The majority of the ticks were nymphs (62%), 31% were females and 7% larvae; 10.7% of the nymphs, 20.3% of the females but no larvae were found to be infected with B. burgdorferi s.l., the agent of Lyme borreliosis (LB). This observation supports for Central Europe the conclusions drawn from North America about nymphal ixodid ticks as the most important vector stage in transmission of LB. In the course of the year, we found the highest proportion of infected nymphal and female ticks taken off humans in June. The detection of borreliae in a human-biting tick is an important step that enables the general practitioner to prescribe prophylactic antimicrobial treatment and to reduce significantly the risk of Lyme disease in the patient.     

莱姆病与蜱的防控

莱姆病(Lyme disease)是一种自然疫源性疾病。病原体为伯氏疏螺旋体(Borrelia burgdorferi);宿主动物主要是野鼠、家畜和鸟类;主要由全沟硬蜱传播。患者有蜱咬史,早期常表现为具有特征性的慢性游走性红斑(erythema chronicum m igrans,ECM),并伴有发热、头痛、肌肉和关节疼痛以及淋巴结肿大等症状。某些病人可出现反复发作性关节炎、心脏与神经系统等病变,是一种多系统受累的传染病。1我国莱姆病疫情动态1986年,在黑龙江省海林县经血清学调查和临床观察发现人群中有莱姆病的发生和流行[1]。随后的调查研究证实我国东北林区人群中莱姆病的…     

我国蜱类作为莱姆病传播媒介的研究概况

莱姆病(Lyme disease)又称莱姆包柔体病,是由伯氏疏螺旋体(Borrelia burgdorferi)感染引起的一种人畜共患自然疫源性疾病,因首次在美国康涅狄格州的莱姆镇发现而得名.由于本病分布广、传播快、致残率高,严重影响人类健康,已被世人所重视,并对该病的病原分子生物学、传染源、传播途径、保护易感人群、临床和治疗等研究方面均不同程度地取得了可喜的进展[1-3].其中在莱姆病传播途径的调查研究中发现,莱姆病多数是被蜱叮咬后在其伤口处引起环状红斑,然后转移到心脏、神经系统等,后期出现莱姆病关节炎.Burgdorfer等1981年在美国纽约附近莱姆病流行区(Shelter)岛上,从达敏硬蜱(I.dammini)体内发现螺旋体,当时暂定为Ixodes dammini螺旋体.用感染蜱叮咬新西兰白兔,70～84 d后试验兔的皮肤上全部出现红斑,经间接免疫荧光测定,病兔血清抗莱姆病螺旋体均为阳性,提出从达敏硬蜱体内发现的螺旋体是莱姆病的致病因子.之后,国内外有关学者做了较系统地研究,证实硬蜱在莱姆病的流行传播过程中起着重要的媒介作用.     

Ticks parasitizing humans in a Lyme disease endemic area of southern New York State

A total of 126 tick specimens were submitted by tick bite victims to the Westchester County Department of Health, White Plains, New York, and to the New York Medical College, Medical Entomology Laboratory, Armonk, New York, during 1985. These included 96 (76.2%) Ixodes dammini, 26 (20.6%) Dermacentor variabilis, and two (1.6%) Amblyomma americanum. I. dammini parasitism was reported during all months of the year except December and February and involved all life stages. Only D. variabilis adults parasitized humans, with all cases occurring in the spring and summer. The mean age of I. dammini victims was 24.5 years, with 39.0% under age 10 years. This age group also accounted for 52.0% of all D. variabilis victims (mean age, 16.8 years). The majority of I. dammini and D. variabilis were though to be acquired in the victims' yards (68.6 and 64.7%, respectively). Attachment sites for these species were significantly different, with I. dammini nymphs found most frequently on the lower extremities and I. dammini adults and D. variabilis adults found primarily on the head. Prophylactic antibiotic treatment was prescribed by a physician for 40.8% of I. dammini victims, compared with 4.5% of the D. variabilis victims. Lyme disease was reported by two patients during the course of the study. Neither had received prophylactic therapy at the time of the reported tick bite.     

A ten-year study of tick biting in Mississippi: implications for human disease transmission

To determine exactly which tick species bit people in Mississippi, information was gathered on ticks involved in human biting cases for the ten-year period, January 1, 1990-December 31, 1999. Specimens were identified by the author and, in most cases, confirmed by personnel at the Institute of Arthropodology and Parasitology, Georgia Southern University. A total of 119 ticks were recovered from 73 humans during the study period. Seven tick species were represented; most common included the lone star tick, Amblyomma americanum, the gulf coast tick, A. maculatum, the American dog tick, Dermacentor variabilis, and the black-legged deer tick, Ixodes scapularis. Interestingly, no immature Ixodes scapularis were collected. there were several unusual records. Twelve larvae of Amblyomma tuberculatum, a species associated with the gopher tortoise, were removed from a patient. Two Dermacentor albipictus larvae were collected from an elderly woman with no travel history except her backyard. One Dermacentor sp. nymph, removed from a man in central MS, was not even a North American species. One adult female Dermacentor variabilis was involved in a clinical case of tick paralysis. These findings indicate that, although we know which tick species are common human biters, unusual/unreported tick-human interactions may be more common than we think.     

Relapsing fever-like spirochetes infecting European vector tick of Lyme disease agent

To determine whether relapsing fever-like spirochetes associated with hard ticks may infect Ixodes ricinus ticks in central Europe, we screened questing ticks for 16S rDNA similar to that of Asian and American relapsing fever-like spirochetes. We compared the prevalence of these spirochetes to that of Lyme disease spirochetes transmitted by the same vector. Relapsing fever-like spirochetes infect 3.5% of questing vector ticks in our three central European sites near the Rhein Valley. These spirochetes differ genetically from their American and Asian analogs while being relatively homogeneous in the region we sampled. The Lyme disease genospecies most commonly detected in central Europe are distributed broadly, whereas those that are less frequently found appear to be place-specific. The absence of co-infected ticks suggests that relapsing fever-like and Lyme disease spirochetes may not share hosts. Exposure risk for relapsing fever-like spirochetes is similar to that of certain Lyme disease genospecies. Although many persons may be bitten by ticks infected by relapsing fever-like spirochetes, health implications remain unknown.     

Potential for Lyme disease in Maine: deer survey of distribution of Ixodes dammini, the tick vector.

A survey of deer brought to tagging stations at 24 sites in Main revealed the presence of the deer tick, Ixodes dammini, on 5.1 percent of deer. Ticks were found almost exclusively on deer from southwest coastal sites in the state. The potential for endemic Lyme disease in coastal Maine merits further study.     

Influenza: an emerging disease.

Because all known influenza A subtypes exist in the aquatic bird reservoir, influenza is not an eradicable disease; prevention and control are the only realistic goals. If people, pigs, and aquatic birds are the principal variables associated with interspecies transfer of influenza virus and the emergence of new human pandemic strains, influenza surveillance in these species is indicated. Live-bird markets housing a wide variety of avian species together (chickens, ducks, geese, pigeon, turkeys, pheasants, guinea fowl), occasionally with pigs, for sale directly to the public provide outstanding conditions for genetic mixing and spreading of influenza viruses; therefore, these birds should be monitored for influenza viruses. Moreover, if pigs are the mixing vessel for influenza viruses, surveillance in this population may also provide an early warning system for humans.     

Lyme disease in New Jersey outdoor workers: a statewide survey of seroprevalence and tick exposure.

To evaluate the spread of Lyme disease in New Jersey, we conducted a statewide cross-sectional study of Lyme disease seroprevalence in a high-risk occupational group of outdoor employees. Of the 689 employees who participated in the study, 39 (5.7 percent) were positive for antibody to B. burgdorferi, the causative agent of Lyme disease. Seroprevalence varied markedly by county; unexpectedly high seroprevalence rates were found in several northern counties (Sussex, Hudson, and Hunterdon). Furthermore, some southern counties (Atlantic, Cape May, and Ocean) with large tick populations (as measured by self-reported exposure to ticks) had low seroprevalence rates which were inversely correlated with self-reported preventive practices. These data suggest that lyme disease, as measured by seroprevalence of antibody to B. burgdorferi, may be spreading beyond the southern portion of the state where it had been previously well documented and that preventive behaviors may play an important role in minimizing the risk of the disease.     

路侧树荫绿化带的蠓类及一新种描述

2011年8-10月在位于北京丰台一院区内路侧绿化树荫带,以挥网法和灯诱法进行了蠓类调查采集,共采获蠓类500余只,其中有毛蠓3种、铗蠓5种,并发现和描述了安氏毛蠓新种。     

Specialty pharmacy: an emerging area of interest for medical management.

Specialty pharmaceuticals are expensive injectable and infusion therapies used to treat patients with chronic or life-threatening diseases. The high cost of these agents and their frequent usage in chronic diseases represent not only challenges, but also opportunities for medical management programs to improve the quality of care and moderate the rapid cost escalation seen in the industry. The number and variety of these agents have been increasing significantly, with hundreds of drug candidates in the development pipeline. The specialty pharmacy industry also is going through a consolidation stage, both horizontally and vertically. Industry approaches to medical management include the acquisition of specialty pharmacy companies, restrictive contracting to achieve concentrated buying power, and the development of utilization management strategies.     

Antibiotic therapy for Lyme disease in Maryland.

The recommended treatment of Lyme disease is evolving and important questions remain unanswered, such as (a) Are inexpensive oral regimens effective in curing acute illness and preventing arthritic, neurologic, and cardiac manifestations or are much more costly, and potentially toxic, intravenous antibiotics required? (b) Are relatively short 2- to 3-week courses of antibiotics sufficient or are prolonged regimens of a month, or more, better? This study reviews antibiotic therapy prescribed by Maryland physicians for the 283 cases reported in 1991 that meet the Centers for Disease Control and Prevention''s case definition for Lyme disease. The purpose of the review was to obtain baseline information on the antibiotics being used by physicians in practice to treat patients that they believe have Lyme disease. The most frequently prescribed antibiotics for either the 60 percent of patients presenting with erythema migrans or the 40 percent with arthritic, neurologic, or cardiac manifestations were oral doxycycline (47 percent), tetracycline (11 percent), and amoxicillin (13 percent). Seventy-one percent of therapeutic courses were for 2 to 3 weeks. Amoxicillin was used in two-thirds of children younger than 8 years. Sixty (21 percent) received intravenous therapy, of which ceftriaxone, with or without other antibiotics, was almost always (95 percent) used. Intravenous therapy was more frequently given to those with arthritic, neurologic, and cardiac manifestations than to those with erythema migrans (odds ratio = 3.7) and to those with these systemic symptoms along with erythema migrans than to those with erythema migrans alone (odds ratio = 3.8).(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-tick saliva antibody: a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.

Anti-tick saliva antibody (ATSA) has potential as a biologic marker of exposure to tick bites. In 1989, we conducted a cross-sectional study of 304 outdoor workers in Monmouth County, New Jersey, to evaluate associations between self-reported tick exposure, ATSA status, and Lyme disease antibody status. ATSA levels 1) were correlated with an index of tick exposure on the basis of three self-reported measures of tick exposure and outdoor hours worked per week (p = 0.01); 2) were consistently higher in pet owners compared with persons without pets (p = 0.03); and 3) when examined by duration since last tick bite, peaked at 3-5 weeks after tick bite and then declined (p = 0.06). ATSA levels dichotomized at the 75th percentile (approximately two standard deviations above the mean ATSA optical density of 25 subjects who denied recent tick exposure) were associated with self-reported tick exposure: adjusted odds ratios for high ATSA levels were 4.2 (95% confidence interval (CI) 0.9-18.9) for moderate (versus none) tick exposure and 5.8 (95% CI 1.2-27.2) for high (versus none) tick exposure. Finally, high ATSA levels were associated with Lyme disease seropositivity, with an adjusted odds ratio of 3.2 (95% CI 1.3-7.6). The data suggest that ATSA is a biologic marker of tick exposure that is a risk factor for Lyme disease seropositivity.     

Epidemiological and aetiological evidence for transmission of Lyme disease by adult Ixodes persulcatus in an endemic area in China

Involvement of adult Ixodes persulcatus ticks in the transmission of Lyme disease in Hailin County, Heilongjiang Province, China, is reported. In 1986 from April through August adult I. persulcatus was the dominant tick in this endemic area with an infection rate of 43% for the Lyme disease spirochaete, Borrelia burgdorferi. The incidence of Lyme disease cases presenting the symptom of erythema chronicum migrans (ECM) within this area was correlated with the seasonal abundance of adult I. persulcatus and the number of people bitten by ticks. The frequency of ECM formation in all age groups varied and was associated with the frequency of tick bites. In addition, a strain of B. burgdorferi was isolated from a pool of six female I. persulcatus collected from this area. We demonstrate that the seasonal abundance of adult I. persulcatus and its frequent attachment to humans result in the spring and summer transmission of Lyme disease in this endemic area. The role of immature I. persulcatus in Lyme disease transmission is apparently minimal.     

Protective value of prophylactic antibiotic treatment of tick bite for Lyme disease prevention: An animal model

Clinical studies have demonstrated that prophylactic antibiotic treatment of tick bites by Ixodes scapularis in Lyme disease hyperendemic regions in the northeastern United States can be effective in preventing infection with Borrelia burgdorferi sensu stricto, the Lyme disease spirochete. A large clinical trial in Westchester County, NY (USA), demonstrated that treatment of tick bite with 200 mg of oral doxycycline was 87% effective in preventing Lyme disease in tick-bite victims (Nadelman, R.B., Nowakowski, J., Fish, D., Falco, R.C., Freeman, K., McKenna, D., Welch, P., Marcus, R., Agúero-Rosenfeld, M.E., Dennis, D.T., Wormser, G.P., 2001. Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N. Engl. J. Med. 345, 79–84.). Although this excellent clinical trial provided much needed information, the authors enrolled subjects if the tick bite occurred within 3 days of their clinical visit, but did not analyze the data based on the exact time between tick removal and delivery of prophylaxis. An animal model allows for controlled experiments designed to determine the point in time after tick bite when delivery of oral antibiotics would be too late to prevent infection with B. burgdorferi. Accordingly, we developed a tick-bite prophylaxis model in mice that gave a level of prophylactic protection similar to what had been observed in clinical trials and then varied the time post tick bite of antibiotic delivery. We found that two treatments of doxycycline delivered by oral gavage to mice on the day of removal of a single potentially infectious nymphal I. scapularis protected 74% of test mice compared to controls. When treatment was delayed until 24 h after tick removal, only 47% of mice were protected; prophylactic treatment was totally ineffective when delivered ≥2 days after tick removal. Although the dynamics of antibiotic treatment in mice may differ from humans, and translation of animal studies to patient management must be approached with caution, we believe our results emphasize the point that antibiotic prophylactic treatment of tick bite to prevent Lyme disease is more likely to be efficacious if delivered promptly after potentially infectious ticks are removed from patients. There is only a very narrow window for prophylactic treatment to be effective post tick removal.     

Longitudinal evaluation of an educational intervention for preventing tick bites in an area with endemic lyme disease in Baltimore County,Maryland

The authors attempted to determine whether a targeted educational intervention in an area with endemic Lyme disease could increase knowledge, positive attitudes, and reported behaviors related to tick bite prevention and consequently decrease tick bites, as measured by a biomarker of tick bites. Between April and September of 1999, 317 subjects in Baltimore County, Maryland, were randomized to receive either tick-related or general health-related educational materials bimonthly through the mail. At each of three clinic visits, participants completed a self-administered questionnaire and provided a serum sample. Anti-recombinant tick calreticulin antibody (ARTCA), measured in ng/ micro l, was used as a biomarker of tick bites. Linear and logistic regression analyses were used to determine 1) whether the educational intervention was associated with a change in knowledge, attitudes, and behaviors (KAB) and 2) whether change in KAB predicted change in ARTCA levels. Proportions of desired responses increased significantly among intervention subjects versus the comparison group on KAB measures related to examining the body for ticks and insect repellent use. Levels of ARTCA were low among all study subjects. Only six of 37 models exhibited a significant relation between change in a KAB variable and change in ARTCA levels over time. The behavioral intervention was associated with an increase in the KAB measures in the intervention group, but this change was not associated with change in ARTCA levels.     

Prevention of Lyme disease in Dutch children: analysis of determinants of tick inspection by parents

BACKGROUND: This study examined factors that discriminate between parents who regularly inspect their children for ticks and those who do not do so. METHODS: Knowledge, cognitive and emotional attitudes, social influences, and self-efficacy expectations were assessed in 230 parents living in high endemic regions. RESULTS: Regression analysis showed that moral norms, emotional attitude, anticipated regret, role models, and stress self-efficacy were positively associated with inspection behavior. CONCLUSIONS: Health education programs not only need to stimulate parental knowledge and discuss the health effects of tick bite prevention, they also need to stress the emotional benefits of tick bite prevention for children and parents and induce positive norms toward inspecting others. Furthermore, they need to stimulate openness about inspection behaviors, since the modeling examples of partners, relatives, and grandparents and the behavior of friends discriminate between inspecting and noninspecting parents. Finally, education programs should clearly indicate how tick inspection works, how the need for it should be communicated to the children, and how to take enough time to do it.