Borreliacidal activity of saliva of the tick Amblyomma americanum

Amblyomma americanum (Linneaus) (Acari: Ixodidae), an important tick vector of human and animal disease, is not a competent vector of the bacterial agent of Lyme disease, Borrelia burgdorferi, although its range overlaps the geographical distribution of Lyme disease within the United States. A possible mechanism that could prevent acquisition of B. burgdorferi spirochetes from infected hosts is the toxic effect of A. americanum saliva on B. burgdorferi. The data presented here indicate that after 24 and 48 h of exposure to A. americanum saliva, significantly fewer B. burgdorferi were alive compared to treatment controls as assessed by spirochete motility under dark-field microscopy and resistance to the dead stain, propidium iodide. After 48 h, fewer than 13% of saliva-exposed B. burgdorferi were alive. In contrast, significantly more B. burgdorferi exposed to Ixodes scapularis (Acari: Ixodidae) saliva survived after 24 or 48 h compared to A. americanum saliva or treatment controls.     

Estimation of the Transmission Probability of Lyme Borreliosis

Whether physicians should prophylactically treat tick bites in areas endemic for Lyme disease has been debated. The high rates of tick infection (10–50%) found in Lyme disease-endemic areas suggest that tick bites should be treated; conversely, the low rates of Lyme disease (1–4%) found in recent clinical trials of untreated tick-bite victims suggest caution in treatment. Medical advice given from Lyme-disease World Wide Web sites is equally contradictory, ranging from suggesting that all tick bites should be treated to suggesting that no tick bites be treated. To clarify this issue, we estimate the transmission probability of the causative agent of Lyme disease, Borrelia burgdorferi, for different durations of tick attachment. The data used to estimate this transmission probability is obtained from previously published animal studies. The accuracy of these estimates is assessed by comparing model predictions of the number of Lyme disease cases to that actually observed in clinical studies of Lyme disease. Our results suggest that tick bites should be treated only when it is known that the duration of tick attachment is longer than 48 hours.     

Epidemiology of canine babesiosis in relation to the activity ofDermacentor reticulatus in southern Jura (France)

Dates of onset of canine babesiosis within a hyperendemic focus in France (Rhone Valley, south of Jura and north of the Alps) were compared to the seasonal population level of the adult stage ofDermacentor reticulatus over a 12-month period (December 1982–November 1983). Cases of babesiosis occurred in spring and fall when adultD. reticulatus were active. The fluctuations of the vector tick population and the onsets of canine babesiosis were also correlated with climatic changes: no tick activity or clinical cases of disease were detected in winter (low temperature) or in summer. The slight disparities observed between both distributions might be explained by various factors such as the development of immunity against the parasites, the intervals between tick bites and appearance of symptoms of the disease, or the asynchrony between different biotopes.     

The effects of the bont tick, Amblyomma hebraeum, on milk production of Sanga and Sanga x Brahman cattle

Abstract. The effects of adults of the bont tick, Amblyomma hebraeum on the milk production of Sanga and Sanga x zebu (Brahman) cattle were measured over a period of 11 weeks in the lowveld of Zimbabwe in the summer of 1986. Four groups of lactating cows, consisting of two breeds, each divided into a high and low tick treatment, were exposed to very low or high challenges of ticks and their milk production measured by weighing their calves before and after suckling. The liveweight gains (LWG) of the calves were also measured.
Tick burdens on the infested groups averaged around fourteen engorging females of A.hebraeum per day, which amounted to infestations of about 150 adult ticks. That is greater than most observed field infestations. This caused no significant reduction in milk yield or calf growth over the whole period, provided the teats of the dams had not been damaged by ticks. Mismothering occurred when teats were damaged. No breed differences were observed so all data was pooled for further analysis. Average calf LWGs of the high tick groups were reduced by 2.2kg (P < 0.01) during one 4-week period but overall the 3.9 kg difference in LWG of the tick treatment groups was not quite significant (P < 0.10). Although there was a poor relationship between tick numbers and reduced milk yield or calf LWG, the effects were always in the direction expected. The effects averaged 6 ± lOg reduction of milk and 2.6 ± 1.8g loss of LWG of calves for every female tick that engorged. It was concluded that milk production is not an important consideration when estimating the losses in production caused by A.hebraeum on Brahman x Sanga or Sanga breeds of cattle. Losses due to teat or udder damage could be much more important and need to be quantified.     

Tick tubes reduce blacklegged tick burdens on white-footed mice in Pennsylvania,USA

Lyme disease cases are increasing in the United States. The vector of the pathogen that causes Lyme disease is the blacklegged tick (Ixodes scapularis Say) (Acari:Ixodidae). While there are several tick control options, many are expensive or involve large-scale or ecological interventions such as landscape acaricide spraying or wildlife baiting. Tick control tubes, cardboard tubes with acaricide-treated cotton that can be used as nesting material by tick hosts, offer an alternative to more invasive tick control by treating tick hosts with an acaricide. In this study, tick tubes with cotton treated with two formulations of acaricide and water as a control were evaluated for wildlife use and for tick burden reductions on Peromyscus spp. an important reservoir host for the Lyme disease pathogen. Tick tubes were deployed for four weeks. Ticks parasitizing Peromyscus spp. and cotton use by wildlife were evaluated pre-deployment and post-deployment. Cotton from both treatments was used similarly, and permethrin-treated cotton was used more frequently than the control. In addition, I. scapularis were eliminated from hosts captured in treatment plots post-tick tube deployment. Tick tubes show promise as a tool for tick control on Peromyscus spp., especially as part of an integrated pest management plan.     

Factors affecting the virulence of entomopathogenic nematodes to engorged female Boophilus annulatus ticks

The laboratory trials rank the virulence of entomopathogenic nematode strains (3 heterorhabditids and 6 steinernematids) to engorged female Boophilus annulatus ticks according to 3 parameters of the infection process: the effect of exposure time on tick mortality, the quantity of nematodes that penetrate ticks, and the rate of tick mortality after the injection of 1, 2, or 3 nematodes. Exposure of the ticks to heterorhabditid strains for 6 hr resulted in >80% mortality, but only 20 or 65% mortality after exposure to most steinernematids. The quantity of nematodes recovered per tick exposed to nematodes for 6 days averaged from 16 to 141. For steinernematids, a negative correlation was obtained between tick mortality and the average quantity of nematodes recovered. Injecting 1 infective juvenile from 1 of 2 heterorhabditid strains into each tick resulted in close to 100% mortality. Increasing the quantity of nematodes injected into each tick had little or no additive effect on tick mortality.     

An uncommon severe clinical course of European tick-borne encephalitis

Tick-borne encephalitis (TBE) is the major European arbovirosis. Man is often infected by the tick bite; laboratory infections as well as infections after consumption of nonpasteurized milk have occasionally been reported. TBE typically takes a biphasic course. After an incubation period (7-14 days usually), the prodromal symptoms occur. The first stage of the disease lasts 1-8 days. After an afebrile asymptomatic interval of approximately 1-week the second stage develops, in which TBE may manifest as isolated meningitis, meningoencephalitis, meningoencephalomyelitis and/or radiculitis. The mortality rate is 0-3.3%. There is high frequency of sequelae. Patients who have suffered from a TBE infection are immune for the rest of their lives. At present there is no effective antiviral therapy and management is strictly supportive. Active immunization against TBE is recommended for all subjects living in and travelling to areas of risk. Passive immunization is recommended only within 48 hours after a tick bite. The authors present the case report of 75-years old female subject, who suffered from the uncommon severe clinical course of TBE--with the development of consciousness impairment, tetraplegia, and dyspnoea (demanding ventilatory support). Her state was complicated by the transient left side faciobrachial motor Jackson's convulsions, blood pressure instability, heart arrhythmia, respiratory infection, anemia, and by the development of critical illness neuropathy. Although she made slow progress during treatment, she died on the 114th day because of suspected aspiration.     

Mapping and monitoring tick (Acari,Ixodida) distribution,seasonality, and host associations in the United Kingdom between 2017 and 2020

Tick-borne disease risk is intrinsically linked to the distribution of tick vector species. To assess risk and anticipate disease emergence, an understanding of tick distribution, host associations, and seasonality is needed. This can be achieved, to some extent, using passive surveillance supported by engagement with the public, animal health, and public health experts. The Tick Surveillance Scheme (TSS) collects data and maps tick distribution across the United Kingdom (UK). Between 2017 and 2020, 3720 tick records were received and 39 tick species were detected. Most records were acquired in the UK, with a subset associated with recent overseas travel. The dominant UK acquired species was Ixodes ricinus (Ixodida: Ixodidae, Linnaeus), the main vector of Lyme borreliosis. Records peaked during May and June, highlighting a key risk period for tick bites. Other key UK species were detected, including Dermacentor reticulatus (Ixodida: Ixodidae, Fabricius) and Haemaphysalis punctata (Ixodida: Ixodidae, Canestrini & Fanzago) as well as several rarer species that may present novel tick-borne disease risk to humans and other animals. Updated tick distribution maps highlight areas in the UK where tick exposure has occurred. There is evidence of increasing human tick exposure over time, including during the COVID-19 pandemic, but seasonal patterns remain unchanged.     

Studies on the economics of ticks in Zambia

Two herds of experimental Sanga cattle were maintained under traditional savanna grazing management for three years in the Central Province of Zambia. One herd was kept free of ticks by regular acaricide treatment, while the other was given no tick control. Milk production, growth rate, fertility and mortality were monitored throughout the trial. The tick-free herd performed significantly better than the tick-infested herd, but the value of the additional production was much less than the cost of the acaricide used. it is concluded that there is no economic justification for intensive tick control under these conditions. However, strategic tick control would be justified if the quantity of acaricide used could be reduced by 50% without any major reduction in benefits. The results indicate that treating calves below 45 days of age reduces their performance, as does treating cows during periods of very low tick challenge. Therefore, it seems likely that economically beneficial strategic tick control policies could be developed.     

Ticks collected from selected mammalian hosts surveyed in the Republic of Korea during 2008-2009

A tick survey was conducted to determine the relative abundance and distribution of ticks associated with selected mammals in the Republic of Korea (ROK) during 2008-2009. A total of 918 ticks were collected from 76 mammals (6 families, 9 species) captured at 6 provinces and 3 Metropolitan Cities in ROK. Haemaphysalis longicornis (54.4%) was the most frequently collected tick, followed by Haemaphysalis flava (28.5%), Ixodes nipponensis (7.6%), Ixodes pomerantzevi (4.8%), Ixodes persulcatus (4.6%), and Haemaphysalis japonica (0.1%). Adults (57.0%) and nymphs (28.7%) of Ixodes and Haemaphysalis spp. were collected most frequently from medium or large mammals in this survey, while few larvae (14.3%) were collected. Hydropotes inermis was the most frequently captured mammal (52.6%), with a 16.4 tick index and 5 of 6 species of ticks collected during this survey. H. longicornis (69.7%) was the predominant tick collected from H. inermis, followed by H. flava (22.2%), I. persulcatus (6.1%), I. nipponensis (1.8%), and H. japonica (0.2%).     

Rejection of ticks from guinea pigs by anti-hapten-antibody-mediated degranulation of basophils at cutaneous basophil hypersensitivity sites: role of mediators other than histamine

Previous studies have established that recruitment of basophils to sites of tick feeding in guinea pigs is required to effect immune resistance. In the current study, actively sensitized guinea pigs treated three times daily with H-1 (mepyramine) and H-2 (cimetidine) histamine receptor antagonists, during the challenge tick infestation period, expressed normal resistance to Amblyomma americanum larvae. Similarly, naive guinea pigs treated with anti-histamines four times daily, beginning 7 days before transfer of immune serum and tick challenge and continuing through the tick infestation period, also expressed normal antibody-mediated resistance to A. americanum. These results indicated that histamine was not an important basophil mediator of the resistance response. Ticks allowed to feed on tissue rich in basophils that were induced by sensitization and subsequent local challenge with non-tick protein antigen, keyhole limpet hemocyanin (KLH), expressed normal yield. Ticks that fed on similar tissue rich in basophils induced by sensitization and challenge with KLH, in which the basophils expressed anti-picryl specificity due to systemic passive transfer of anti-picryl antibodies, were rejected when basophils were induced to degranulate by i.v. challenge with picryl antigen at 6 hr (29% rejection), 12 hr (18% rejection), 24 hr (22% rejection), and 48 hr (37% rejection) post-tick attachment. However, basophil degranulation at 18, 72 and 96 hr post-tick attachment had no adverse effect on tick feeding. These hosts were protected from systemic anaphylaxis by treatment with the anti-histamine mepyramine. Release of histamine occurred at tick feeding sites, but vasoactive effects were blocked by mepyramine treatment as evidenced by a lack of increased vascular permeability (bluing) at these sites compared with non-tick-infested tissues, or to cutaneous basophil hypersensitivity (CBH) sites of animals not protected with mepyramine. These results indicate that local recruitment and subsequent degranulation of basophils via immune mechanisms dependent on non-tick antigens can lead to tick rejection, and that basophil-derived mediators other than histamine are involved in this immune resistance response to A. americanum ticks. The identity of the crucial basophil mediator(s) is not known. The significant susceptibility of ticks to basophil-mediator release at 6 to 12 hr and 24 to 48 hr post-attachment coincides with the tick attaching and fast-feeding phases, respectively, suggesting that these phases of tick parasitism are particularly susceptible to the effect of basophil mediators other than histamine.     

Wild turkey (Meleagris gallopavo) as a host of ixodid ticks, lice, and Lyme disease spirochetes (Borrelia burgdorferi sensu lato) in California state parks

Rio Grande wild turkeys (Meleagris gallopavo intermedia) were evaluated as potential hosts of ixodid ticks, lice, and Lyme disease spirochetes (Borrelia burgdorferi sensu lato [s.l.]) in three state parks in Sonoma County, California, USA, during 2003 and 2004. In total, 113 birds were collected, 50 (44.2%) of which were found to be infested by 361 ixodid ticks representing three species: the western black-legged tick (Ixodes pacificus, n=248), the rabbit tick (Haemaphysalis leporispalustris, n=112), and one American dog tick (Dermacentor variabilis). Year-round the prevalence of all ticks combined was unrelated to the age or sex of turkeys, and the prevalence of infestation by I. pacificus (35.4%) was significantly higher than it was for either H. leporispalustris (14.2%) or D. variabilis (0.9%). The proportion of the two prevalent tick species differed significantly by life stage with 86.3% of the I. pacificus and 82.1% of the H. leporispalustris enumerated being nymphs and larvae, respectively. Three species of lice were collected, including the chicken body louse Menacanthus stramineus (12.5% of total), Chelopistes meleagridis (37.5% of total), and Oxylipeurus polytrapezius (50% of total). The records for all three ticks are the first ever from wild turkeys, and those for the lice are the first from this host in the far-western United States. Wild turkeys potentially were exposed to the feeding activities of I. pacificus nymphs infected with B. burgdorferi s.l. as 15% of host-seeking nymphs (n=200) collected in woodlands used by turkeys as roosting or foraging areas were infected mainly with B. burgdorferi sensu stricto (s.s.). However, only one (1%) of 90 turkey blood specimens tested by PCR contained B. burgdorferi s.s., and four in vitro, complement-protein assays demonstrated that domestic turkey serum is moderately bacteriolytic for this spirochete. Taken together, these findings indicate that wild turkeys are important avian hosts of I. pacificus nymphs, but they appear to be inconsequential hosts of B. burgdorferi s.l.     

Effect of O. porcinus Tick Salivary Gland Extract on the African Swine Fever Virus Infection in Domestic Pig

African swine fever is a haemorrhagic disease in pig production that can have disastrous financial consequences for farming. No vaccines are currently available and animal slaughtering or area zoning to restrict risk-related movements are the only effective measures to prevent the spread of the disease. Ornithodoros soft ticks are known to transmit the African swine fever virus (ASFV) to pigs in farms, following the natural epidemiologic cycle of the virus. Tick saliva has been shown to modulate the host physiological and immunological responses during feeding on skin, thus affecting viral infection. To better understand the interaction between soft tick, ASFV and pig at the bite location and the possible influence of tick saliva on pig infection by ASFV, salivary gland extract (SGE) of Ornithodoros porcinus, co-inoculated or not with ASFV, was used for intradermal auricular inoculation. Our results showed that, after the virus triggered the disease, pigs inoculated with virus and SGE presented greater hyperthermia than pigs inoculated with virus alone. The density of Langerhans cells was modulated at the tick bite or inoculation site, either through recruitment by ASFV or inhibition by SGE. Additionally, SGE and virus induced macrophage recruitment each. This effect was enhanced when they were co-inoculated. Finally, the co-inoculation of SGE and virus delayed the early local spread of virus to the first lymph node on the inoculation side. This study has shown that the effect of SGE was powerful enough to be quantified in pig both on the systemic and local immune response. We believe this model should be developed with infected tick and could improve knowledge of both tick vector competence and tick saliva immunomodulation.     

Stage-structured infection transmission and a spatial epidemic: a model for Lyme disease

A greater understanding of the rate at which emerging disease advances spatially has both ecological and applied significance. Analyzing the spread of vector-borne disease can be relatively complex when the vector's acquisition of a pathogen and subsequent transmission to a host occur in different life stages. A contemporary example is Lyme disease. A long-lived tick vector acquires infection during the larval blood meal and transmits it as a nymph. We present a reaction-diffusion model for the ecological dynamics governing the velocity of the current epidemic's spread. We find that the equilibrium density of infectious tick nymphs (hence the risk of human disease) can depend on density-independent survival interacting with biotic effects on the tick's stage structure. The local risk of infection reaches a maximum at an intermediate level of adult tick mortality and at an intermediate rate of juvenile tick attacks on mammalian hosts. If the juvenile tick attack rate is low, an increase generates both a greater density of infectious nymphs and an increased spatial velocity. However, if the juvenile attack rate is relatively high, nymph density may decline while the epidemic's velocity still increases. Velocities of simulated two-dimensional epidemics correlate with the model pathogen's basic reproductive number (R0), but calculating R0 involves parameters of both host infection dynamics and the vector's stage-structured dynamics.     

Prevalence of Borrelia burgdorferi sensu lato in ticks collected from migratory birds in Switzerland

The prevalence of ticks infected by Borrelia burgdorferi sensu lato on birds during their migrations was studied in Switzerland. A total of 1,270 birds captured at two sites were examined for tick infestation. Ixodes ricinus was the dominant tick species. Prevalences of tick infestation were 6% and 18.2% for birds migrating northward and southward, respectively. Borrelia valaisiana was the species detected most frequently in ticks, followed by Borrelia garinii and Borrelia lusitaniae. Among birds infested by infected ticks, 23% (6/26) were infested by B. lusitaniae-infected larvae. Migratory birds appear to be reservoir hosts for B. lusitaniae.     

稻鸭共作对水稻条纹叶枯病发生规律的影响

由灰飞虱传毒危害的水稻条纹叶枯病是近年来在我国部分稻作区严重发生的病毒病害.作为稻作生产生态实践模式之一的稻鸭共作技术对稻田病虫草具有显著的控制效应,然而目前还没有关于稻鸭共作对灰飞虱和条纹叶枯病影响的报道.因此,于2004～2005年在南京农业大学东台试验场进行了田间实验,共设计了4个处理,分别为常规稻作区（不养鸭、施药）、稻鸭共作区（养鸭、不施药）和秧田期覆盖防虫网、栽后大田稻鸭共作区（秧田覆盖防虫网、栽后稻田养鸭、不施药）和对照区（不养鸭、不施药）.结果表明：稻鸭共作以及秧田期覆盖防虫网、栽后大田稻鸭共作处理对灰飞虱有显著的控制效应,因此也显著降低了两处理在水稻整个生长期间条纹叶枯病的发病率;稻鸭共作处理对条纹叶枯病的综合防效为79.44﹪,略高于常规稻作78.82﹪的防效,而秧田期覆盖防虫网、栽后大田稻鸭共作处理对稻田灰飞虱和条纹叶枯病的防治效果最好,对条纹叶枯病的防效超过94.01﹪.总之,通过以上试验结果可知,稻鸭共作尤其是秧田期覆盖防虫网、栽后稻鸭共作处理为防治条纹叶枯病提供了一条安全高效的生态控制途径.     

Experimental infection of the rabbit tick,<Emphasis Type="Italic"> Haemaphysalis leporispalustris</Emphasis>, with the bacterium<Emphasis Type="Italic"> Rickettsia rickettsii</Emphasis>, and comparative biology of infected and uninfected tick lineages

The present study consisted of two experiments that evaluated experimental infections of Haemaphysalis leporispalustris ticks by a Brazilian strain of Rickettsia rickettsii, and their effect on tick biology. In experiment I, ticks were exposed to R. rickettsii during the larval, nymphal or adult stages by feeding on rabbits (Oryctolagus cuniculus) needle-inoculated with R. rickettsii, and thereafter reared on uninfected rabbits for the entire next tick generation. Regardless of the tick stage that acquired the infection, all subsequent tick stages were shown to be infected by PCR (infection rates varying from 1.3 to 41.7%), and were able to transmit R. rickettsii to uninfected rabbits, as demonstrated by rabbit seroconversion, guinea pig inoculation with rabbit blood, and PCR on rabbit blood. In Experiment II, ticks were exposed to R. rickettsii during the larval stage by feeding on rabbits co-infested with R. rickettsii-infected adult ticks, and thereafter reared on uninfected rabbits until the next generation of larvae. Again, all subsequent tick stages were shown to be infected by PCR (infection rates varying from 3.0 to 40.0%), and were able to transmit R. rickettsii to uninfected rabbits. Thus, it was demonstrated that larvae, nymphs, and adults of H. leporispalustris were able to acquire and maintain the R. rickettsii infection by transstadial and transovarial transmissions within the tick population, with active transmission of the bacterium to susceptible rabbits by all parasitic stages. Analyses of biological parameters of uninfected and R. rickettsii-infected tick lineages were performed in order to evaluate possible deleterious effects of R. rickettsii to the infected tick lineages. Surprisingly, all but one of the four R. rickettsii-experimental groups of the present study showed overall better biological performance than their sibling uninfected control ticks. Results of the present study showed that H. leporispalustris could support infection by a high virulent strain of R. rickettsii for at least two generations, in which infected tick lineages tended to have better performance than uninfected ticks. Our results support a possible role of H. leporispalustris in the enzootic maintenance of R. rickettsii in Latin America, as previously suggested by earlier works.     

Detection of a questing <Emphasis Type="Italic">Hyalomma marginatum</Emphasis><Emphasis Type="Italic">marginatum</Emphasis> adult female (Acari,Ixodidae) in southern Germany

The first finding of a questing Hyalomma marginatum marginatum female tick in Germany is described. The tick was found in May 2006 on the clothing of a person who had spent the preceding day in rural surroundings in southern Germany. As the infested person had also been visiting Spain where H. m. marginatum is known to occur some weeks prior to finding the tick, it is not clear whether the tick had been imported by him as a female or by another host in a preimaginal stage and succeeded to develop to an adult in Germany. H. m. marginatum is a thermophilic tick species usually occurring in relatively dry and warm regions of southern Europe, northern Africa and some parts of Asia. It is a vector of several disease agents of human relevance including Crimean-Congo hemorrhagic fever virus. Although, by PCR examination, the female was found neither infected with this virus nor with Rickettsia aeschlimannii, another human pathogen which has been found in Spanish Hyalomma ticks, its mere finding should be taken seriously and draw further attention to the increasing problem of the import and spread of putatively tropical vectors of disease to central Europe.     

Detection of Theileria annulata by the PCR in ticks (Acari: Ixodidae) collected from cattle in Mauritania

We report on the detection of Theileria annulata in infected Hyalomma ticks by the PCR using primers derived from the gene encoding the 30 kDa major merozoite surface antigen (Tams1–1). No inhibition of the PCR was observed and as little as 0.1 pg of parasite DNA, corresponding to 12 sporozoites, could be detected in non-infected tick DNA samples, spiked with T. annulata genomic DNA. Hyalomma dromedarii ticks, fed on a calf experimentally infected with T. annulata, were used to validate the PCR further. The infection rate in the adult ticks, fed as nymphs during the febrile reaction, was high (62%), dropped to zero for 1 day in tick batches that engorged after treatment with ButalexTM and increased to 30% 2 days later and 38% of the ticks acquired the infection after feeding as nymphs during a carrier state piroplasm parasitaemia of less than 0.1%. As an internal control, 16S tick rDNA sequences could be amplified from T. annulata-negative tick samples. Finally, 202 adult ticks from Mauritania, collected from zebu cattle carrying low levels of Theileria piroplasms, were tested by the PCR. Thirty-eight out of 52 (73%) and 17 out of 30 (57%) H. dromedarii from the Gorgol and Trarza regions, respectively and two out of 30 (7%) Hyalomma marginatum rufipes from the Gorgol region were positive. Hyalomma marginatum rufipes, Rhipicephalus evertsi evertsi and Rhipicephalus guilhoni from the Trarza region were negative. These findings confirm that H. dromedarii is the main vector of T. annulata in Mauritania and that the PCR is a useful method of determining the infection rates in ticks collected from cattle carrying low levels of T. annulata piroplasms.     

Microarray analyses of inflammation response of human dermal fibroblasts to different strains of Borrelia burgdorferi sensu stricto

In Lyme borreliosis, the skin is the key site of bacterial inoculation by the infected tick, and of cutaneous manifestations, erythema migrans and acrodermatitis chronica atrophicans. We explored the role of fibroblasts, the resident cells of the dermis, in the development of the disease. Using microarray experiments, we compared the inflammation of fibroblasts induced by three strains of Borrelia burgdorferi sensu stricto isolated from different environments and stages of Lyme disease: N40 (tick), Pbre (erythema migrans) and 1408 (acrodermatitis chronica atrophicans). The three strains exhibited a similar profile of inflammation with strong induction of chemokines (CXCL1 and IL-8) and IL-6 cytokine mainly involved in the chemoattraction of immune cells. Molecules such as TNF-alpha and NF-κB factors, metalloproteinases (MMP-1, -3 and -12) and superoxide dismutase (SOD2), also described in inflammatory and cellular events, were up-regulated. In addition, we showed that tick salivary gland extracts induce a cytotoxic effect on fibroblasts and that OspC, essential in the transmission of Borrelia to the vertebrate host, was not responsible for the secretion of inflammatory molecules by fibroblasts. Tick saliva components could facilitate the early transmission of the disease to the site of injury creating a feeding pit. Later in the development of the disease, Borrelia would intensively multiply in the skin and further disseminate to distant organs.