Exotic Rickettsiae in Ixodes ricinus: fact or artifact?

Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult and presenting these findings as new or potentially pathogenic Rickettsiae should be done with caution: a recent report suggested presence of a known human pathogen, R. australis, in questing I. ricinus ticks in Europe. A refined analysis of these results revealed that R. helvetica was most likely to be misinterpreted as R. australis. Evidence in the literature is accumulating that rickettsial DNA sequences found in tick lysates can also be derived from other sources than viable, pathogenic Rickettsiae. For example, from endosymbionts, environmental contamination or even horizontal gene transfer

Parasites of vectors - Ixodiphagus hookeri and its Wolbachia symbionts in ticks in the Netherlands

<p>Abstract</p> <p>Background</p> <p><it>Ixodiphagus hookeri </it>is a parasitic wasp of ixodid ticks around the world. It has been studied as a potential bio-control agent for several tick species. We suspected that the presence of <it>Wolbachia </it>infected <it>I. hookeri </it>eggs in ticks is responsible for incidental detection of <it>Wolbachia </it>DNA in tick samples.</p> <p>Methods</p> <p>The 28S <it>rRNA </it>and 16S <it>rRNA </it>genes of a specimen of <it>I. hookeri </it>was amplified and sequenced. PCR on part of the 28S <it>rRNA </it>gene was used to detect parasitic wasp DNA in 349 questing <it>Ixodes ricinus </it>ticks from various sampling sites. Furthermore, the <it>wsp </it>gene of <it>Wolbachia </it>was sequenced from the <it>I. hookeri </it>specimen and a subset of ticks was tested using this marker.</p> <p>Results</p> <p>Several sequences from tick specimens were identical to the <it>Wolbachia </it>sequence of the <it>I. hookeri </it>specimen. <it>Ixodiphagus hookeri </it>was detected in 9.5% of all tested ticks, varying between 4% and 26% depending on geographic location. Ten out of eleven sampling sites throughout the Netherlands were positive for <it>I. hookeri</it>. Eighty-seven percent of <it>I. hookeri-</it>positive but only 1.6% of <it>I. hookeri</it>-negative ticks were <it>Wolbachia </it>positive. Detection of <it>I. hookeri </it>DNA was strongly associated with the detection of <it>Wolbachia </it>in ticks.</p> <p>Conclusion</p> <p>This is the first reported case of <it>I. hookeri </it>in the Netherlands. Furthermore <it>I. hookeri </it>harbours <it>Wolbachia </it>species and is broadly distributed in the Netherlands. While detection of <it>Wolbachia </it>DNA in ticks might often be due to parasitism with this wasp, other sources of <it>Wolbachia </it>DNA in ticks might exist as well.</p

Role of sand lizards in the ecology of Lyme and other tick-borne diseases in the Netherlands

<p>Abstract</p> <p>Background</p> <p>Lizards are considered zooprophylactic for almost all <it>Borrelia burgdorferi </it>species, and act as dilution hosts in parts of North America. Whether European lizards significantly reduce the ability of <it>B. burgdorferi </it>to maintain itself in enzootic cycles, and consequently decrease the infection rate of <it>Ixodes ricinus ticks </it>for <it>B. burgdorferi </it>and other tick-borne pathogens in Western Europe is not clear.</p> <p>Results</p> <p>Ticks were collected from sand lizards, their habitat (heath) and from the adjacent forest. DNA of tick-borne pathogens was detected by PCR followed by reverse line blotting. Tick densities were measured at all four locations by blanket dragging. Nymphs and adult ticks collected from lizards had a significantly lower (1.4%) prevalence of <it>B. burgdorferi </it>sensu lato, compared to questing ticks in heath (24%) or forest (19%). The prevalence of <it>Rickettsia helvetica </it>was significantly higher in ticks from lizards (19%) than those from woodland (10%) whereas neither was significantly different from the prevalence in ticks from heather (15%). The prevalence of <it>Anaplasma </it>and <it>Ehrlichia </it>spp in heather (12%) and forest (14%) were comparable, but significantly lower in ticks from sand lizards (5.4%). The prevalence of <it>Babesia </it>spp in ticks varied between 0 and 5.3%. Tick load of lizards ranged from 1 - 16. Tick densities were ~ 5-fold lower in the heather areas than in woodlands at all four sites.</p> <p>Conclusions</p> <p>Despite their apparent low reservoir competence, the presence of sand lizards had insignificant impact on the <it>B. burgdorferi </it>s.l. infection rate of questing ticks. In contrast, sand lizards might act as reservoir hosts for <it>R. helvetica</it>. Remarkably, the public health risk from tick-borne diseases is approximately five times lower in heather than in woodland, due to the low tick densities in heather.</p

Ability to cause erythema migrans differs between Borrelia burgdorferi sensu lato isolates

Background: Lyme borreliosis is a tick-borne disease caused by Borrelia burgdorferi sensu lato. The variety of characteristic and non-specific clinical manifestations is partially explained by its genetic diversity. We investigated the ability of B. burgdorferi sl isolates to cause erythema migrans. Methods. The genetic constellation of isolates from ticks was compared to isolates found in erythema migrans. PCR and sequence analysis was performed on the plasmid-encoded ospC and the chromosomal 5S-23S rDNA spacer region (IGS). Results: Seven different B. burgdorferi sl genospecies were identified in 152 borrelia isolates from ticks and erythema migrans biopsies. B afzelii (51%) and B. garinii (27%) were the most common in ticks. From the 44 sequences obtained from erythema migrans samples 42 were B. afzelii, one B. garinii and one B. bavariensis. Significant associations with erythema migrans formation were found for four IGS and two ospC types. Five from 45 ospC types were associated with more than one genospecies. Conclusions: B. burgdorferi sl isolates differ in their propensity to cause erythema migrans. These differences were also found within genospecies. In other words, although B. afzelii was mostly associated with erythema migrans, some B. afzelii isolates had a low ability to cause erythema migrans. Our data further support the occurrence of plasmid exchange between borrelia genospecies under natural conditions

Absence of zoonotic Bartonella species in questing ticks: First detection of Bartonella clarridgeiae and Rickettsia felis in cat fleas in the Netherlands

<p>Abstract</p> <p>Background</p> <p>Awareness for flea- and tick-borne infections has grown in recent years and the range of microorganisms associated with these ectoparasites is rising. <it>Bartonella henselae</it>, the causative agent of Cat Scratch Disease, and other <it>Bartonella </it>species have been reported in fleas and ticks. The role of <it>Ixodes ricinus </it>ticks in the natural cycle of <it>Bartonella </it>spp. and the transmission of these bacteria to humans is unclear. <it>Rickettsia </it>spp. have also been reported from as well ticks as also from fleas. However, to date no flea-borne <it>Rickettsia </it>spp. were reported from the Netherlands. Here, the presence of <it>Bartonellaceae </it>and <it>Rickettsiae </it>in ectoparasites was investigated using molecular detection and identification on part of the gltA- and 16S rRNA-genes.</p> <p>Results</p> <p>The zoonotic <it>Bartonella clarridgeiae </it>and <it>Rickettsia felis </it>were detected for the first time in Dutch cat fleas. <it>B. henselae </it>was found in cat fleas and <it>B. schoenbuchensis </it>in ticks and keds feeding on deer. Two <it>Bartonella </it>species, previously identified in rodents, were found in wild mice and their fleas. However, none of these microorganisms were found in 1719 questing <it>Ixodes ricinus </it>ticks. Notably, the gltA gene amplified from DNA lysates of approximately 10% of the questing nymph and adult ticks was similar to that of an uncultured <it>Bartonella-</it>related species found in other hard tick species. The gltA gene of this <it>Bartonella-</it>related species was also detected in questing larvae for which a 16S rRNA gene PCR also tested positive for "<it>Candidatus </it>Midichloria mitochondrii"<it/>. The gltA-gene of the <it>Bartonella-</it>related species found in <it>I. ricinus </it>may therefore be from this endosymbiont.</p> <p>Conclusions</p> <p>We conclude that the risk of acquiring Cat Scratch Disease or a related bartonellosis from questing ticks in the Netherlands is negligible. On the other hand fleas and deer keds are probable vectors for associated <it>Bartonella </it>species between animals and might also transmit <it>Bartonella </it>spp. to humans.</p

Uterine adenocarcinoma with feline leukemia virus infection

Feline endometrial adenocarcinomas are uncommon malignant neoplasms that have been poorly characterized to date. In this study, we describe a uterine adenocarcinoma in a Persian cat with feline leukemia virus infection. At the time of presentation, the cat, a female Persian chinchilla, was 2 years old. The cat underwent surgical ovariohystectomy. A cross-section of the uterine wall revealed a thickened uterine horn. The cat tested positive for feline leukemia virus as detected by polymerase chain reaction. Histopathological examination revealed uterine adenocarcinoma that had metastasized to the omentum, resulting in thickening and the formation of inflammatory lesions. Based on the histopathological findings, this case was diagnosed as a uterine adenocarcinoma with abdominal metastasis. To the best of our knowledge, this is the first report of a uterine adenocarcinoma with feline leukemia virus infection

Towards an integrated approach in surveillance of vector-borne diseases in Europe

Vector borne disease (VBD) emergence is a complex and dynamic process. Interactions between multiple disciplines and responsible health and environmental authorities are often needed for an effective early warning, surveillance and control of vectors and the diseases they transmit. To fully appreciate this complexity, integrated knowledge about the human and the vector population is desirable. In the current paper, important parameters and terms of both public health and medical entomology are defined in order to establish a common language that facilitates collaboration between the two disciplines. Special focus is put on the different VBD contexts with respect to the current presence or absence of the disease, the pathogen and the vector in a given location. Depending on the context, whether a VBD is endemic or not, surveillance activities are required to assess disease burden or threat, respectively. Following a decision for action, surveillance activities continue to assess trends