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PubMed1996

Photoperiodic response in the soft tick, Ornithodoros turicata.

The effects of photoperiod on the feeding, development and quiescent behavior of the burrow-dwelling soft tick, Ornithodoros turicata (Dugès) were investigated. Ticks were assigned randomly to either continuous darkness (DD), a short-day photoperiod (L:D 10:14), a long-day photoperiod (L:D 14:10) or constant light (LL). Ticks reared under constant light succumbed to much higher mortality than those reared under the other conditions. However, photoperiod did not induce quiescent behavior in O. turicata; the ticks were active and fed regularly throughout the study. Also, ticks reared in continuous darkness developed more slowly than those reared under short-day or long-day conditions. In contrast, pre-oviposition period was significantly longer for ticks reared in long-day conditions. Egg-hatch success was significantly higher for ticks reared in continuous darkness than for those reared under the photoperiods. The stage-specific effects of photoperiod on O. turicata are adaptive; these ticks very likely utilize photoperiod information to predict seasonal conditions.

Animals↗
PubMed1995

The relationship between tick (Amblyomma hebraeum) infestation and immunity to heartwater (Cowdria ruminantium infection) in calves in Zimbabwe.

The occurrence of endemic stability for heartwater (Cowdria ruminantium infection) is a controversial issue, because the means by which young cattle and other neonatal ruminants become infected and acquire immunity to the disease have never been adequately explained. We conducted a study in a heartwater-endemic area in southeastern Zimbabwe to investigate the relationships between calf immunity to C. ruminatium, infestations of the tick vector Amblyomma hebraeum and dam, colostral and calf antibody titres to C. ruminantium. Two groups of cows (tick-infested and acaricide-treated) were artificially inseminated and then monitored through pregnancy and lactation by means of tick counts and serum antibody titres. The calves born to the cows in each treatment group were similarly monitored from birth until after weaning, when they were challenged with a heartwater stabilate (Ball-3 vaccine). Colostrum was collected from the cows on the days that the calves were born. Serum and colostrum samples were screened for Cowdria-specific antibodies using an indirect fluorescent antibody test. The cows and calves in the acaricide-treated group remained essentially tick-free for the duration of the study. The cows in the tick-infested group were continuously infested with A. hebraeum, but their calves only became infested between 12 and 31 weeks after birth. Cowdria-specific antibodies were detected in the sera of the cows and calves and in the colostrum of both treatment groups, but the titres were consistently higher in the tick-infested group than in the acaricide-treated group. Antibodies, probably of maternal origin since the precolostral serum titres were negative, were present in the calves of both groups for at least 8 weeks after birth. Between Weeks 24 and 52 postpartum, the antibody titres of the tick-infested group of calves were significantly correlated with the numbers of A. hebraeum present on the animals. The antibody titres of the calves in the acaricide-treated group increased considerably following challenge with heartwater stabilate, 60 weeks after birth. No clinical heartwater was detected in either group of calves following inoculation of stabilate, and it was concluded that the calves in both groups were immune to the disease. In the acaricide-treated group, immunity did not correlate with exposure to tick-transmitted infections. Hence, we concluded that the calves in both groups had probably been infected by vertical transmission around the time of birth. Such early infections are likely to have been controlled by maternal antibodies or by an unidentified immune mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1996

Ticks of domestic animals in the Macedonia region of Greece.

A study was carried out on ticks of domestic animals in the Macedonia region of Greece. During 1983-1986, 11,620 tick specimens, belonging to 18 species and subspecies, were collected from cattle, sheep, goats and dogs, in 64 localities throughout Macedonia. Rhipicephalus bursa, the most common tick, and Hyalomma marginatum marginatum occurred in all bioclimatic zones, as well as the two one-host ticks, Boophilus annulatus and H. detritum scupense, which were present in fewer localities. R. turanicus, R. sanguineus, Ixodes gibbosus and H. anatolicum excavatum occurred essentially in the mesomediterranean bioclimatic zone. I. ricinus, Dermacentor marginatus and Haemaphysalis ticks (Hm. inermis, Hm. punctata, Hm. sulcata, Hm. parva) were found frequently in the biotopes of the attenuated mesomediterranean and submediterranean bioclimates. Rhipicephalus adults and the two-host Hyalomma ticks were active in the spring-summer period. Ixodes spp., Haemaphysalis spp., D. marginatus, as well as H. detritum scupense and the immature stages of R. bursa appeared during autumn and winter. Hyalomma and Boophilus ticks fed mainly on cattle. R. sanguineus almost exclusively parasitized dogs, which were also the only hosts from which I. hexagonus has been collected. The infestations were generally weak or moderate. Few heavy infestations were observed on cattle, especially in autumn. Most of the tick species showed a strong preference for some particular sites on the vertebrate body. This predilection could vary according to the host species.

Animals↗
PubMedDate not supplied

Transmission of Crimean-Congo haemorrhagic fever virus from experimentally infected sheep to Hyalomma truncatum ticks.

Crimean-Congo haemorrhagic fever (CCHF) virus was inoculated into West African sheep that were simultaneously infested with adult Hyalomma truncatum ticks. Certain sheep developed a viraemia and antibodies, indicating virus infection and replication; however, the length and magnitude of the viraemia and serological responses corresponded to the animals' immunological status. Tick attachment and feeding was not influenced by sheep infection. CCHF virus infection was acquired by 11-33% of female and 0-60% of male ticks. Infection in the ticks did not influence their feeding success, as judged by weight at drop-off, and the weight of eggs produced by infected and non-infected ticks was similar. Transovarial transmission of CCHF virus was demonstrated in 2 of 12 (17%) egg batches from infected female ticks, but in none of 19 egg batches from ticks that tested negative for CCHF virus. Our results suggest that under certain ecological conditions, sheep may serve to amplify CCHF virus in nature through horizontal transmission and that the maintenance cycle also may be influenced by transovarial transmission to the next generation of ticks.

Animals↗
PubMed1994

Protein phosphatase 1 and 2A in tick salivary glands as assessed by responses to okadaic acid.

Crude protein phosphatase activity was inhibited 80% by nanomolar okadaic acid (OA) in salivary glands of unfed ticks but only 40% in salivary glands of feeding ticks. An additional 40% of protein phosphatase was inhibited by micromolar OA in the salivary glands of feeding ticks but only 10% in salivary glands of unfed ticks. Cyclic AMP and OA alone or together increased the phosphorylation of multiple proteins in a plasma membrane-enriched 900 g supernatant fraction of tick salivary glands. Exogenous cyclic AMP stimulated increased incorporation of phosphate into proteins with approximate molecular weights of 109, 70, 64, 51, 48, 42 and 18.5 kDa. Micromolar OA in the absence of exogenous cyclic AMP stimulated increased incorporation of phosphate into proteins with apparent molecular weights of 109, 93, 74.5, 70, 51, 48, 42 and 18.5 kDa. Cyclic AMP and OA (10(-6) and 10(-9) M) stimulated significantly greater phosphorylation of an 18.5 kDa mol. wt protein above that observed in response to stimulation by OA (10(-6) and 10(-9) M) or exogenous cyclic AMP alone. Micromolar okadaic acid inhibited the amount and number of proteins but not volume of saliva secreted by whole ticks in response to stimulation by DA and theophylline. However, micromolar and nanomolar okadaic acid inhibited the ability of dopamine to stimulate fluid secretion by isolated salivary glands. Overall, the data support the existence of type 1 and 2A protein phosphatases in tick salivary glands and a role for protein phosphatases in modulating tick salivary secretion.

Animals↗
PubMed2006

A secreted cystatin from the tick Haemaphysalis longicornis and its distinct expression patterns in relation to innate immunity.

Proteins capable of selective and specific inhibition of cysteine protease have been identified as cystatins and are isolated from a variety of microbes and tissues of animals and plants. The physiological function of these proteins has been proposed to be the regulation of protein turnover and defense against pathogens as well as the balance of the host-parasite immune relationship. Genes encoding cystatins have been found in several species of ticks, but the function of cystatin in ticks is not understood. We cloned a gene encoding cystatin from tick H. longicornis and designated it as Hlcyst-2 (H. longicornis cystatin-2). Its full-length cDNA is 569 bp, and it encodes a putative 133 amino acid protein with an obvious signal peptide. Sequence analysis demonstrated that it has significant homology with the known cystatin. The recombinant protein was expressed in a GST-fused soluble form in Escherichia coli and purified by affinity chromatography. The inhibitory activity of the recombinant protein against papain, cathepsin L, and cathepsin B was identified by fluorogenic substrate analysis. Cystatin was mostly expressed in the tick midgut and hemocyte. Blood feeding induced significantly increased expression in the midgut. Real-time PCR confirmed that LPS-injected adult ticks expressed Hlcyst-2 1.6 more times than the PBS-injected control; Babesia gibsoni-infected larvae ticks expressed Hlcyst-2 1.8 more times than normal larvae ticks. The recombinant protein also showed a significant growth-inhibitory effect on Babesia bovis cultured in vitro. These results indicated this cystatin Hlcyst-2 is involved in tick innate immunity.

Amino Acid Sequence↗
PubMed2005

Ixodid tick species attaching to dogs in Hungary.

A survey was carried out to investigate the occurrence of hard tick species (Acari: Ixodidae) infesting domestic dogs in Hungary. Forty veterinary clinics from a wide geographical area were asked to collect hard ticks from dogs and to complete a questionnaire. In total, 25 veterinary clinics submitted 900 ticks from 310 dogs. Intensity of infestation ranged from one to 78 per dog. The most preferred sites of tick attachment in decreasing order were head, neck and legs. The majority of ticks (91.7%) were adults, which were identified to species level, the others were nymphs. Six species were found: Dermacentor reticulatus (48.9%), Ixodes ricinus (43.2%), Ixodes canisuga (5.6%), Haemaphysalis concinna (2%) and there was one specimen of both Dermacentor marginatus and Ixodes hexagonus. Single species infestation with I. ricinus or D. reticulatus was found on 145 (46.8%) and 120 animals (38.7%), respectively. Mixed infestation caused by these two species was detected on 24 dogs (7.7%). I. canisuga and H. concinna were found on seven and five dogs, respectively. D. reticulatus and I. ricinus were collected almost throughout the year, except for a single month. The activity peaks were in spring and in autumn for both species. Based on clinical signs, canine babesiosis was diagnosed by the veterinarians in 66 (21.3%) tick infested dogs. These dogs were more frequently infested with D. reticulatus than the others. Our data contribute to the understanding of geographical and seasonal distribution of ixodid tick species infesting dogs in Hungary. The implication of these data, for the risk of canine tick borne diseases is discussed.

Animals↗
PubMed1986

Borrelia transfer by ticks during their life cycle. Studies on laboratory animals.

Ticks of the species Ixodes ricinus were cultured in the laboratory. Yellow silver rabbits, gerbils and white mice served as blood hosts. Borrelia burgdorferi could be detected by means of an IFA test in homogenates of female ticks, their eggs as well as the respective larval and nymphal ticks. Blood infection of splenectomized gerbils and ordinary white mice or of ordinary white mice alone has been demonstrated after feeding of larval or nymphal ticks on them, respectively. Spirochetemia started 5 to 8 days after feeding and lasted for ca 3 weeks. Two distinct peaks in the cell count of spirochetal organisms per ml blood plasma could be observed on days 11-13 (5 X 10(5) to 2 X 10(6) cells/ml) and 17-19 (10(5) cells/ml), regardless whether splenectomized gerbils or white mice were used. The results display that B. burgdorferi is vertically from the female ticks to their eggs and transstadially transmitted. The transmission-rate from larval to nymphal ticks is 100%. These findings show the tick itself as a main reservoir of B. burgdorferi. The established mouse-model appears to be a useful tool to detect Borrelia carrying ticks.

Animals↗
PubMed2001

cDNA cloning, characterization and vaccine effect analysis of Haemaphysalis longicornis tick saliva proteins.

Immunological control of ticks is currently the only sustainable and practical alternative method to the current use of acaricides which has serious limitations. The success of this method is dependent upon identification and cloning of potential tick vaccine antigens. We used a combination of immuno-screening of an adult tick cDNA library as well as the 3 and 5 rapid amplification of cDNA ends to clone two cDNAs, encoding tick saliva proteins from Haemaphysalis longicornis. The two cDNAs herein named HL 34 and 35 are 1000 bp each and encode polypeptides with 292 and 321 amino acid residues respectively. Northern blotting analysis of total RNA from ticks at different feeding stages revealed that expression of both HL 34 and HL35 mRNAs is induced during the slow feeding phase. We speculate that the functions of both genes are closely associated with blood feeding. Expression analysis by RT-PCR showed that both genes are expressed in other tick organs in addition to salivary glands. Recombinant HL 34 was successfully expressed in Escherichia coli and its suitability as a tick vaccine antigen was analyzed in rabbits. We propose that rHL34 could be a useful component of a cocktail tick vaccine.

Amino Acid Sequence↗
PubMed2003

A comparison of susceptibilities to infection of four species of Hyalomma ticks with Theileria annulata.

In this comparative study unfed nymphs of four Hyalomma tick species (Hyalomma anatolicum anatolicum, Hyalomma anatolicum excavatum, Hyalomma detritum and Hyalomma marginatum marginatum) were allowed to engorge on calves experimentally infected with Theileria annulata. The infection prevalence in the salivary glands of the adult female and male ticks of each Hyalomma species used in the study were assessed. The infection prevalence with T. annulata was high and did not vary markedly in the four Hyalomma tick species. The mean number of infected acini per tick in female and male ticks was different with female ticks having higher numbers of infected acini than the male ticks. The sex difference was more significant between H.a. anatolicum and H.a. excavatum than between H. detritum and H.m. marginatum. This study clarifies the roles of four Hyalomma tick species, and their sex, in the development of T. annulata.

Animals↗
PubMed1994

Characterization of Borrelia burgdorferi isolated from different organs of Ixodes ricinus ticks collected in nature.

Borrelia burgdorferi was isolated from 22 out of 133 adult Ixodes ricinus ticks collected from vegetation at two sites in Switzerland. From 17 ticks, spirochetes could be isolated from more than one organ. When the different isolates obtained from one tick were compared by SDS-PAGE analysis, differences in the protein profiles were observed in 8 cases. The isolates were further compared by immunological methods using mono- and polyclonal antibodies. Differences were observed in the proteins of 31-35 kDa and 18-25 kDa. Genetic divergence among isolates was evaluated by use of a B. burgdorferi specific gene probe for ospA. Correlation could be observed between immunological differences in OspA defined by monoclonal antibody LA31 and genetic variation of ospA as judged by restriction fragment length polymorphism (RFLP). Our findings indicate that systemic infection in unfed I. ricinus adults, as reflected by isolation of B. burgdorferi from multiple organs of one tick, is more frequent (8/22, 36%) than previously described (5%). Moreover, the presence of different B. burgdorferi phenotypes/genotypes in one tick is described for the first time. The findings may have bearings (i) on the time of tick attachment required for spirochete transmission since borreliae are already present in the salivary glands of systemically infected ticks at the beginning of the blood meal and (ii) perhaps also on the diversity of B. burgdorferi phenotypes inoculated by these ticks.

Animals↗
PubMed2002

Rhipicephalus ticks infected with Rickettsia and Coxiella in Southern Switzerland (Canton Ticino).

Ticks of the Rhipicephalus sanguineus species complex may be vector of various pathogens including Rickettsia conorii (the etiological agent of the Mediterranean spotted fever) and Coxiella burnetii (cause of the Query (Q) fever). R. sanguineus ticks have been imported in several parts of central and northern Europe, especially in environments such as kennels and houses providing the appropriate microclimatic conditions and the blood source necessary for their survival. Since 1940 these ticks have occasionally been recorded in Switzerland. In Ticino (the southern part of Switzerland), they have been reported since 1980 and their probable establishment in this area has been suggested in the '90s. By means of PCR and direct sequencing, we tested the identity of these ticks (using 12S rDNA gene) and the occurrence of Rickettsia spp. (using 16S rDNA, gltA and OmpA genes) as well as Coxiella sp. (using 16S rDNA). The results indicated that in Ticino, two different tick species coexist, i.e. R. sanguineus sensu stricto and Rhipicephalus turanicus. A few individuals of R. sanguineus sensu stricto are infected with Rickettsia massiliae/Bar29, which are strains of unknown pathogenicity. Coxiella sp., an endosymbiont of Rhipicephalus ticks, has also been identified in both tick species. Due to climatic changes towards global warming, imported tick species may therefore adapt to new area and might be considered as epidemiological markers for a number of infectious agents transmitted by them.

Animals↗
PubMed1993

In vitro feeding of instars of the ixodid tick Amblyomma variegatum on skin membranes and its application to the transmission of Theileria mutans and Cowdria ruminatium.

An in vitro feeding method using rabbit or cattle skin membranes, applied successfully to all stages (larvae, nymphae and adults) of the ioxodid tick, Amblyomma variegatum, is described. The feeding apparatus consisted of a blood container with a membrane placed on top of a tick containment unit. A carbon dioxide atmosphere of between 5 and 10% and a temperature of 37 degrees C were used as stimulants for the attachment of the ticks. High CO2 concentrations in the atmosphere improved the feeding success of all instars. The effect of anticoagulation methods for the bloodmeal was investigated, and heparinized blood was found to be the most suitable for tick feeding. When the bloodmeal was replaced by tissue culture medium for feeding nymphs the subsequent moulting success was reduced. Adult ticks of both sexes remained attached for up to 16 days, until completion of their bloodmeals. All stages of the tick fed on whole blood in the artificial feeding system and all reached engorged weights less than those achieved by control ticks fed on experimental animals. A large proportion of ticks, fed artificially on whole blood, moulted or laid eggs successfully. The method was successfully applied for the transmission of Theileria mutans and Cowdria ruminantium to cattle.

Animals↗
PubMed2005

Tick-borne Great Island Virus: (I) Identification of seabird host and evidence for co-feeding and viraemic transmission.

Great Island Virus (GIV) is an arbovirus present in the tick Ixodes uriae, a common ectoparasite of nesting seabirds. Common guillemot (Uria aalge) and black-legged kittiwake (Rissa tridactyla) are the preferred and most abundant hosts of I. uriae on the Isle of May, Scotland. As part of a study to understand the epidemiology of GIV, the ability of guillemot and kittiwake to support tick-borne transmission of GIV was examined. GIV was present in ticks feeding in isolated guillemot colonies and guillemots had virus-specific neutralizing antibodies demonstrating previous GIV infection. By contrast, only uninfected ticks were found in colonies inhabited solely by kittiwakes. GIV was isolated from kittiwake ticks in colonies which also contained breeding guillemots but no virus-specific neutralizing antibodies were present in blood samples of kittiwake on which infected ticks were feeding. Thus guillemots are the main vertebrate hosts of GIV on the Isle of May whereas kittiwakes do not appear to be susceptible to infection. Virus infection of adult ticks feeding on guillemots was highly efficient and may involve both viraemic transmission and transmission from infected to uninfected ticks feeding together on birds that do not develop a patent viraemia.

Animals↗
PubMed1998

Theileria lestoquardi--maturation and quantification in Hyalomma anatolicum anatolicum ticks.

The maturation and quantification of Theileria lestoquardi (T. hirci) parasites in unfed and partially fed adult Hyalomma anatolicum anatolicum ticks was studied using (1) methyl green pyronin (MGP) staining of salivary glands, (2) in vitro infection of peripheral blood mononuclear cells (PBM) with parasites harvested from infected ticks and (3) a semi-quantitative polymerase chain reaction (PCR). With MGP staining the greatest infection rate was seen in unfed ticks. Feeding resulted in a gradual reduction in the number of infected acini with a concomitant increase in the maturity of the parasites. In vitro infection of sheep PBM with titrated group-up tick supernate (GUTS) demonstrated that infectivity peaked between 2 and 4 days of tick feeding whereas GUTS prepared from unfed ticks was not infective. The polymerase chain reaction (PCR) was both sensitive and specific, detecting T. lestoquardi DNA in unfed and partially fed ticks, with a maximum sensitivity of 0.022 infected acinus/tick in 2-day fed ticks, though it gave no indication of the infectivity of the parasite.

Animals↗
PubMed1998

Evidence to show that an agent that cross-reacts serologically with Cowdria ruminantium in Zimbabwe is transmitted by ticks.

The serological diagnosis of heartwater based on reactions to the immunodominant Cowdria ruminantium major antigen protein-1 (MAP-1) is impaired by the detection of false-positive reactions. In this study, the prevalence of false-positive reactions on seven heartwater-free farms in Zimbabwe was determined to be 8-94% by immunoblotting against C. ruminantium antigens. The highest prevalence of false-positives on Spring Valley Farm correlated with the presence of Rhipicephalus evertsi evertsi ticks. The other tick species found on these seven farms were Hyalomma truncatum and Hyalomma marginatum rufipes. Rhipicephalus evertsi evertsi ticks collected from Spring Valley Farm and fed on seronegative sheep caused seroconversion in one of two sheep. This sheep developed a mild febrile reaction and C. ruminantium MAP-1 antigen reactive antibodies 3 weeks after the ticks started feeding. Polymerase chain reactions (PCRs), conducted using C. ruminantium-specific primers on ticks collected from the seven farms and on some of the R. e. evertsi ticks that had caused seroconversion in one sheep, were negative. However, some of these ticks gave positive PCRs with DNA primers which amplify a 350 bp DNA fragment of the 16s rRNA gene from all ehrlichial agents indicating the presence of infection with one or more Ehrlichia species. Although attempts to isolate the cross-reacting agent from the sheep were unsuccessful, this study demonstrates that false-positive reactions with the MAP-1 C. ruminantium antigen are associated with agents transmitted by ticks.

Animals↗
PubMed2001

Evidence for the utility of the Bm86 antigen from Boophilus microplus in vaccination against other tick species.

The Bm86 antigen, as originally identified in Boophilus microplus, is the basis of commercial tick vaccines against this tick species. The potential for using this antigen or homologues of the antigen in vaccination against other tick species has been assessed. We have conducted vaccine trials in cattle using the B. microplus-derived recombinant Bm86 vaccine (TickGARD) using pairs of vaccinated calves and control calves. These were infested with B. microplus and Boophilus decoloratus larvae simultaneously. For both species, the numbers of engorged female adult ticks, their weight and egg-laying capacity were all reduced, leading to a reduction in reproductive capacity of 74% for B. microplus and 70% for B. decoloratus. Hyalomma anatolicum anatolicum ticks were fed both as immatures as well as adults on vaccinated calves and non-vaccinated controls. There was an overall 50% reduction in the total weight of nymphs engorging on vaccinated calves, and a suggestion of a subsequent effect on feeding adults. For Hyalomma dromedarii there was a 95% reduction in the number of nymphs engorging and a further 55% reduction in weight of those ticks surviving. Rhipicephalus appendiculatus and Amblyomma variegatum ticks were fed simultaneously both as immatures and subsequently as adults. There was no evidence for a significant vaccination effect. Finally, the amino acid sequence of a Bm86 homologue found in H. a. anatolicum unequivocally demonstrated the conservation of this molecule in this species. Our strategy for the development of multivalent anti-tick vaccines is discussed in relation to these findings.

Amino Acid Sequence↗
PubMed1997

Infestation of mammals by Ixodes ricinus ticks (Acari: Ixodidae) in south-central Sweden.

Infestation by Ixodes ricinus ticks on rodents, hares and cervids was examined at Bogesund, 10 km north of Stockholm, in south-central Sweden during 1991-1994 and on varying hares (Lepus timidus) at Stora Karlsö and Gotska Sandön in the Baltic Sea during 1992-1993. At Bogesund, there were great differences between two consecutive years in the number of I. ricinus larvae infesting bank voles (Clethrionomys glareolus). The seasonal pattern of infestation by I. ricinus larvae and nymphs on bank voles was unimodal in 1991, with peaks in June-July and bimodal in 1992, with peaks in June and August. Male bank voles, compared to females and older voles, compared to young voles, harboured greater numbers of I. ricinus ticks. Apodemus mice, compared to bank voles, harboured greater numbers of I. ricinus ticks. Ixodes ricinus larvae engorged on Apodemus mice were heavier than larvae engorged on bank voles and resulted in larger nymphs. However, there was no difference in the proportions of viable nymphs resulting from larvae engorged on mice or voles. The ranges in the numbers of I. ricinus ticks infesting individual hosts were 1-451 for rodents, 16-2374 for hares and 428-2072 for roe deer (Capreolus capreolus). These ranges of tick numbers are estimated to represent potential blood losses from individual hosts of approximately 0.2-65% for rodents, 0.2-13% for hares and 0.3-9.0% for roe deer. Within the populations of all host species examined, the distributions of all stages of I. ricinus were clumped, with most host individuals harbouring few ticks and only a few individuals harbouring many ticks. The data suggest that, even though a small proportion of tick hosts may be severely affected, the direct effects of feeding by I. ricinus are unlikely to play an important role on mammal population dynamics.

Age Factors↗