Haemaphysalis longicornis calreticulin is not an effective molecular tool for tick bite diagnosis and disruption of tick infestations

BACKGROUND

Tick calreticulin (CRT) is a calcium-binding protein secreted into the host during blood feeding. It has been used as a biomarker of tick exposure and has potential as an anti-tick vaccine, but there is no information about these uses for Haemaphysalis longicornis CRT (HlCRT). We synthesized recombinant H. longicornis CRT (rHlCRT) and evaluated its potential for tick bite diagnosis and for disrupting tick infestations.

METHODS

The responses of mice and rabbits exposed to H. longicornis ticks were measured with ELISA to determine the antibody level against rHlCRT. To evaluate the effects of rHlCRT-induced anti-tick immunity, engorgement weight, tick engorgement index (TEI), feeding duration, ecdysis rate, and egg weight per engorged tick were compared between ticks fed on immunized and normal mice.

RESULTS

Mean anti-tick CRT antibody levels in sera collected from mice at 1 and 15 days after primary tick exposure were not significantly different from the mean antibody levels in negative control mice that were not bitten by ticks (all P values > 0.05). No significant anti-HlCRT IgG responses developed in mice after second exposure to tick bites compared with the level of anti-HlCRT antibody response in negative control mice (all P values > 0.25). For rabbits, no significant differences in the antibody levels were observed in animals before challenge infestation and after tick exposures, and in animals after two tick exposures (all P values > 0.10). There were no significant differences in the body weight of ticks fed on immunized and normal mice (all P values > 0.15). No significant differences in TEI were observed between ticks fed on immunized mice and normal control mice (all P values > 0.50). There were no significant differences in feeding duration for female ticks, and feeding duration and ecdysis rate for nymphs in the experimental and control groups (all P values > 0.10 for feeding duration and P value = 0.19 for ecdysis rate). We did not observe a significant difference in egg weight per tick in the rHlCRT-immunized and the control groups (P = 0.88).

CONCLUSIONS

HlCRT in H. longicornis tick saliva proteins appears to be nonimmunogenic to mammalian hosts like mice and rabbits. Vaccination with rHlCRT did not generate effective immunity against parthenogenetic and bisexual H. longicornis nymphs or female ticks. These results indicate that HlCRT is not a suitable molecular candidate for H. longicornis tick bite diagnosis and not effective for the disruption of tick infestations.

Tick paralysis in a free-ranging bobcat (Lynx rufus)

CASE DESCRIPTION

A free-ranging male bobcat (Lynx rufus) was evaluated because of signs of pelvic limb paralysis.

CLINICAL FINDINGS

Physical examination of the anesthetized animal revealed tick infestation, normal mentation, and a lack of evidence of traumatic injuries. Radiography revealed no clinically relevant abnormalities. Hematologic analysis results were generally unremarkable, and serologic tests for exposure to feline coronavirus, FeLV, FIV, and Toxoplasma gondii were negative. Results of PCR assays for flea- and common tick-borne organisms other than Bartonella clarridgeiae were negative.

TREATMENT AND OUTCOME

Ticks were manually removed, and the patient received supportive care and fipronil treatment. The bobcat made a full recovery within 72 hours after treatment for ticks, and a presumptive diagnosis of tick paralysis was made. Identified tick species included Dermacenter variabilis, Amblyomma americanum, and Ixodes scapularis.

CLINICAL RELEVANCE

To the authors' knowledge, tick paralysis has not previously been reported in felids outside Australia. This disease should be considered a differential diagnosis in felids, including exotic cats, with signs of neuromuscular disease of unknown etiopathogenesis.

Larval tick infestation causing an eruption of pruritic papules and pustules

Ticks are well-documented human parasites and vectors of infectious disease. The larval ("seed") stage is 1 of 3 motile life stages, and larval ticks have been known to attack in droves, causing diffuse pruritic erythematous papules and pustules. In the absence of close examination, larval tick infestation can easily be missed in the wide differential for this clinical presentation. We present 2 cases of larval tick infestation occurring during the summer within the same month at a single institution. Our purpose is to encourage physicians to include larval tick infestation when generating a differential diagnosis for diffuse pruritic erythematous papules and pustules.

Detection of Ehrlichia ruminantium infection in cattle in Cameroon

OBJECTIVES

Ehrlichia ruminantium infection (heartwater) is a major constraint that impacts negatively on the cattle industry development in sub-Saharan Africa and so far, little is known of the presence of heartwater in cattle in Cameroon. This study sought to investigate the prevalence of E. ruminantium infection in cattle in Cameroon and to determine the predictors of infection.

RESULTS

A species-specific semi-nested pCS20 polymerase chain reaction was used to screen the buffy coats from 182 cattle (comprising 82 cattle that received intensive tick control regimen and 100 cattle on strategic tick control) from two study sites in Cameroon for E. ruminantium DNA in a cross-sectional study. E. ruminantium infection was confirmed in 12 (6.6%) of the 182 cattle comprising 11 that received intensive tick control and one on strategic tick control. Of the 12 cattle detected, 11 were apparently healthy and one was clinically diagnosed of heartwater. All DNA sequences of pCS20 amplicons were identical to each other (a representative sequence deposited in GenBank under accession number JQ039939). These findings which have veterinary and epidemiological significance, suggest the need for further investigation to determine the extent and role of heartwater in cattle in Cameroon.

What's eating you? Ixodes tick and related diseases, part 2: diagnosis and treatment of regional tick-borne diseases

The Ixodes tick is an important arthropod vector in the transmission of human disease. Although Lyme disease is the most prevalent zoonosis transmitted by Ixodes ticks, other less common diseases may be encountered, including human granulocytic anaplasmosis, babesiosis, Powassan virus infection, tick-borne encephalitis, Borrelia miyamotoi disease, and tick paralysis. In part 2 of this review, disease presentation, diagnosis, and treatment of these less commonly encountered tick-borne diseases are discussed.

[Tick Infestation of the Eyelid: Case Report and Literature Review]

Tick infestation is rarely seen in ophthalmological practice. We report the case of a 73-year-old woman who presented with edema and erythema of her right upper eyelid. Biomicroscopic examination revealed a tick firmly attached to the eyelid margin. The tick was successfully removed using fine tweezers, and within a few days, the patient had fully recovered without sequelae. Ticks are a threat to public health as they are known vectors of numerous infectious agents responsible for serious pathologies such as Lyme disease. Ticks may also induce cutaneous local reactions, and more rarely, tick paralysis. Since morbidity increases substantially with the duration of the infestation, the tick should be completely removed as soon as possible, and patients should be aware about possible signs of tick related diseases.

Assessment of using recombinant Ixodes ricinus AV422 saliva protein for confirmation of tick bites in hunting dogs as naturally infested hosts

Due to the recorded spreading of ticks in past years, a higher incidence of tick-borne diseases (TBDs) can be expected in the future in endemic areas, but can also pose an emerging public health concern in areas where they have not yet been recognized. Assessment of the exposure of vulnerable hosts to ticks would be a very helpful tool for TBD epidemiological studies, as well as for their proper managing. To confirm previous tick bites, the method of choice is detection of antibodies in host serum as markers developed against injected tick saliva proteins during feeding. We recently showed that the recombinant form of Ixodes ricinus AV422 saliva protein (rIrAV422) can serve for detection of markers in experimentally infested rats. Here we examine whether it can be used in the same manner in naturally exposed hosts. We chose hunting dogs as good sentinel animals. The study group consisted of 15 dogs that varied in breed, age, sex, previous tick infestation history and repellent treatment. Western blot analysis with rIrAV422 as an antigen confirmed the presence of tick bite markers in all analysed dogs. For some of the dogs, their previous tick infestation history was unclear, which emphasizes the usefulness of rIrAV422 for revealing it. Since hunting dogs are naturally infested with different ticks, the potential of rIrAV422 in assessment of general exposure to ticks is highlighted. Use of rIrAV422 can also be helpful in veterinary practice and research as a tool for validation of the efficiency of tick repellent products.

Human otoacariasis caused by Amblyomma testudinarium: Diagnosis and management: Case report

RATIONALE

Tick infestation of the external auditory canal (EAC) constitutes <1% of all patients presenting with ear complaints. Consequently, parameters for the diagnosis and management of ticks in the EAC have not been established.

PATIENT CONCERNS

We report 2 cases of EAC infestation by Amblyomma testudinarium in 2 female patients, aged 12- and 72 years old.

DIAGNOSES INTERVENTIONS AND OUTCOMES

In both patients, otoscopic examination revealed engorged ticks attached to the ear canal. The 12-year-old girl had a narrow EAC, necessitating slight dislodging of the tick to determine if its mouth parts were embedded in the EAC skin. The tick's mouth parts were confirmed to be free, enabling complete removal of the tick. The 72-year-old woman had a wide EAC, enabling tick removal using Hartman's forceps because the tick's mouth parts were confirmed to be free of the skin. Prophylactic tetracycline (200 mg/day) was administered to each patient for 7 days; neither showed any signs of fever or rash.

LESSONS

This report describes 2 patients with A testudinarium infestation of the EAC, and proposes a simple, noninvasive protocol for determining if the tick is anchored to the ear canal.

Relapsing fever

Relapsing fewer is an infection to be considered in the differential diagnosis of an immigrant´s febrile illness. It is a severe, tick-borne or body louse-borne infection caused by the relapsing fever associated borrelia species. The body louse-borne infection is in particular encountered in the Horn of Africa region due to poor hygiene, and has during the past year been described in several European countries as imported by refugees coming from this region. Doctors should thus bear relapsing fever in mind as a differential diagnosis in a febrile refugee having recently arrived in Finland.

Passive surveillance for ticks on horses in Saskatchewan

Passive surveillance of ticks on horses in Saskatchewan revealed that the horses were parasitized by 3 species, Dermacentor albipictus, D. andersoni, and D. variabilis. The nymphs and adults of D. albipictus occurred on horses earlier in the year than did adults of the 2 other species.

Introduction of the exotic tick Hyalomma truncatum on a human with travel to Ethiopia: a case report

An Oregon resident returned from a photography trip to Ethiopia with a male Hyalomma truncatum tick attached to the skin on his lower back. The tick was identified morphologically and deposited in the U.S. National Tick Collection housed at Georgia Southern University, Statesboro, Georgia. The public health importance of Hyalomma species of ticks and diagnostic dilemmas with identifying exotic ticks imported into the U.S. are discussed.

[Detection of Babesia canis (Piroplasmida) DNA in the blood samples and lysates of the ticks Dermacentor reticulatus (Ixodidae) collected in the Tula and Moscow Regions]

Chimeric primers, the sensitivity and specificity of which allow them to be used in both the clinical setting and the epizootological assessment of tick infection by a real-time polymerase chain reaction (RT-PCR) assay, have been designed against Babesia canis infection. The findings suggest that a large number of Babesia DNA copies are detectable in the blood in acute babesiosis. Some animals that had experienced babesiosis developed blood B. canis carriage--a small number oftrophozoites remained alive for a long time. When babesiosis was suspected, its diagnosis could be confirmed by RT-PCR in half of dogs with subclinical signs. The tick concentration of Babesia ranged from several hundred to a few thousand parasites. There were no significant differences in the number of Babesia parasites in the infected ticks in relation to their collection site. However, the occurrence of infected ticks was significantly higher in the places of constant contact with a canine population, which is indicative of the decisive role of dogs in the intensity of an epizootic process in the foci of B. canis infection.

Acute labyrinthitis secondary to aural tick infestation

Aural tick usually menisfests as intolerable otalgia. The severity of pain makes the patient to seek early treatment. Other uncommon symptoms include inner ear dyfunctions such as vertigo and tinnitus. The diagnosis is established by clinical examinaion either by otoscopic evidence of the tick itself, or its fecal remnant. We report a case of patient with acute labyrinthitis features with concurent otoscopic findings of tick fecal material.

[Hard ticks (Mite, Ixodidae) and human ixodidasis]

This article describes carefully parasitism by ticks hard under various medical issues ranging from biological signs of the notes up to the management of the patient follow-up, passing through the induced symptoms and therapeutic procedures. Just dealing therapeutic procedures is especially important because they compare various techniques proposed by the literature and is then proposed technique that determines the lowest risk of transmission of potentially infected material between the mite and man. Despite the treatment of parasitism is considered a medical practice trivial, given the banality of parasitism in fact among the medical community to see applied different treatment protocols are not always entirely accurate.

Tick infestation of the eyelid: a case report in a child

A three-year-old girl presented with a small brown lesion on the right upper eyelid margin. Close examination revealed an insect body attached to the eyelid margin. Microscopic examination of the specimen identified the species of the organism as Ixodes ricinus. The tick was completely removed with blunt forceps. She was treated with lid toilet, irrigation, and application of topical 0.3% ciprofloxacin four times daily to the affected eye. The lesion healed without scarring after one week. No systemic symptoms were observed. Mechanical removal with blunt forceps may be a quick, easy, safe and effective treatment for ticks located on the eyelids.

Larval tick infestation: a case report and review of tick-borne disease

Tick-borne disease in the United States continues to be a threat as people interact with their natural surroundings. We present a case of an 8-year-old boy with a larval tick infestation. Ticks within the United States can carry Lyme disease, Rocky Mountain spotted fever (RMSF), ehrlichiosis, babesiosis, tularemia, tick-borne relapsing fever, and tick paralysis. These preventable diseases are treatable when accurately recognized and diagnosed; however, if left untreated, they can cause substantial morbidity and mortality. This article highlights the knowledge necessary to recognize, treat, and prevent tickborne disease.

[Detection of Babesia caballi (Nuttall, 1910) and Theileria equi (Syn. Babesia equi , Laveran, 1901) by the polymerase chain reaction (PCR) in show and sport horses in the region of Ankara]

The aim of this study was to compare the diagnosis of Babesia caballi and Theileria equi by the polymerase chain reaction (PCR) and microscopic examination of blood specimens collected from show and sport horses in the region of Ankara in 2004. The blood specimens were collected from randomly selected 200 show and sport horses in the region of Ankara during the tick season as well as before and after the tick season for PCR testing. At the same time, Giemsa stained peripheral blood smears were examined for the presence of Babesia spp. and also the horses were examined for the presence of ticks. Of the 200 horse blood samples analyzed, 3% were found to be positive by microscopic examination and and 10 % (B.caballi %3; T.equi %7) by the polymerase chain reaction. The difference between these two methods was confirmed to be statistically important (p < 0,001). This is the first study in which Babesia species were investigated in horses in Turkey using the PCR method. Theileria equi was found to be more prevalent than Babesia caballi.

A case of histologically diagnosed tick infestation on the scalp of a Korean child

A scalp mass surgically excised from a 4-year-old Korean boy was identified as a tick through histological observations. In sections of the mass, characteristic features of a tick, including its gross contour, cuticular structures, well developed musculature and salivary glands, and the capitulum, were discovered. In particular, the capitulum is anteriorly protruded, which strongly suggests that the specimen be a hard tick of family Ixodidae. However, the present histological features were not enough to determine the genus and species of the tick, because information on sectional morphologies of different tick species is unavailable. This is a rare case of tick infestation on the scalp diagnosed in histological sections.

Fecal NIRS: detection of tick infestations in cattle and horses

Anti-tick treatments are often applied concurrent to routine livestock management practices with little regard to actual infestation levels. Prescription treatments against ticks on grazing cattle would be facilitated by non-invasive detection methods. One such method is fecal near infrared spectroscopy (NIRS). Four studies utilizing cattle (Bos spp.) and one with horses (Equus caballus) fed varying diets and infested with either Amblyomma americanum, A. maculatum, A. cajennense or Dermacentor albipictus were conducted to determine the ability of fecal NIRS to identify samples from animals with (High stress) and without (Low stress) a tick burden. Discriminant analysis of each individual trial resulted in R(2)>0.80. Similar analyses utilizing all combinations of four studies, predicting group membership in the remaining study, yielded R(2)>0.80, but correct determinations for Low and High tick stress samples of only 53.4 and 60.1%, respectively. All five trials were combined and a random 10 or 25% of the samples were removed from the calibration. As in the previous calibrations, a high degree of discrimination was achieved (R(2)>0.89). The validation samples were correctly identified at 91.7% for Low stress and 96.3% for High stress, respectively. Difficulties in detecting differences in fecal samples due to confounding effects of trial were overcome by combining calibration sets. Overall, differences in fecal NIR spectra apparently due to tick stress were accurately detected across diet, host species, and tick species.

The epidemiology, diagnosis, management, and prevention of ectoparasitic diseases in travelers

Ectoparasitic diseases have been reported in travelers returning from both developed and developing nations.(1-3) Ectoparasitic diseases afflict the skin and its appendages and orifices, especially the scalp, facial, and pubic hairs; external ears; nares; orbits and eyelids; and genitourinary and rectal orifices. Like endoparasites, ectoparasites may be either obligatory parasites, which need to feed on human hosts to complete their life cycles, or facultative parasites, which prefer to feed on nonhuman hosts and infest humans only as accidental or dead-end hosts.(4,5).

PCR-based detection of Babesia bovis and Babesia bigemina in their natural host Boophilus microplus and cattle

PCR and nested-PCR methods were used to assess the frequency of Babesia bovis and Babesia bigemina infection in Boophilus microplus engorged females and eggs and in cattle reared in an area with endemic babesiosis. Blood and the engorged female ticks were from 27 naturally infested calves and 25 crossbred cows. The frequency of both Babesia species was similar in calves and cows (P>0.05). Babesia bovis was detected in 23 (85.2%) calves and in 25 (100%) cows and B. bigemina was detected in 25 (92.6%) calves and in 21 (84%) cows. Mixed infections with the both Babesia species were identified in 42 animals, 21 in each age category. Of female ticks engorged on calves, 34.9% were negative and single species infection with B. bigemina (56.2%) was significantly more frequent (P<0.01) than with B. bovis (4.7%). Most of the females (60.8%) engorged on cows did not show Babesia spp. infection and the frequency of single B. bovis infection (17.6%) was similar (P>0.05) to the frequency of single B. bigemina infection (15.9%). Mixed Babesia infection was lower (P<0.01) than single species infection in female ticks engorged either in cows (5.7%) or in calves (4.3%). An egg sample from each female was analysed for the presence of Babesia species. Of the egg samples from female ticks infected with B. bovis, 26 (47.3%) were infected while from those from female ticks infected with B. bigemina 141 (76.6%) were infected (P<0.01). The results showed that although the frequency of both species of Babesia was similar in calves and cows, the infectivity of B. bigemina was higher to ticks fed on calves while to those ticks fed on cows the infectivity of both Babesia species was similar.

West Nile virus infection in two alpacas

A male alpaca acutely developed signs of anorexia and fever. Within 2 days, neurologic signs (head tremors and asymmetric ataxia) developed. West Nile virus (WNV) infection was considered a primary differential diagnosis on the basis of 6 previous cases on nearby alpaca farms on which animals had similar clinical signs. Four days after the male alpaca became ill, a female alpaca from the same farm developed similar neurologic signs. In addition to anti-inflammatory and supportive treatments, both alpacas received a transfusion of llama plasma with antibodies against WNV Seven days after the onset of clinical signs, the female alpaca had made a full recovery; however, the more severely affected male died. West Nile virus infection was confirmed post mortem by use of reverse transcriptase-polymerase chain reaction assay and immunohistochemical staining.

Case reports: intra-aural tick infestations in humans in Sri Lanka

Intra-aural tick infestation was detected in 29 patients presenting with acute ear pain in the central province of Sri Lanka during June 1999 to January 2002. The ages ranged from 9 months to 67 years. All showed oedematous aural canals and enlarged adjacent lymph nodes. Of 30 ticks removed, 29 were nymphs of Dermacentor auratus and 1 and male Hyalomma marginatum isaaci.

Identification of Borrelia burgdorferi sensu lato, Anaplasma and Ehrlichia species, and spotted fever group Rickettsiae in ticks from Southeastern Europe

Prevalence data for tick-borne pathogens are used to assess the risk for human health. In this study the presence and identity of Borrelia burgdorferi sensu lato, Ehrlichia, Anaplasma, and Rickettsia species in Bulgarian Ixodes ricinus ticks and in non- Ixodes ticks from Turkey and Albania was determined by polymerase chain reaction (PCR) and reverse line blot hybridization. In the adult Bulgarian ticks, the prevalence of Borrelia burgdorferi sensu lato infection was approximately 40%, while Borrelia afzelii was the predominant species, representing more than half of all Borrelia-positive ticks. Ehrlichia and Anaplasma species were detected in 35% of the adult Ixodes ricinus ticks and in 10% of the nymphs. Sequence analysis of PCR products reacting with the Anaplasma phagocytophila probe revealed a 16S rRNA gene identical to that of the Anaplasma phagocytophila prototype strain. Ehrlichia and Anaplasma species were found in approximately 7% of the non- Ixodes ticks. Sequence analysis of some of these samples revealed the presence of Anaplasma ovis, Ehrlichia canis, and a species closely resembling Ehrlichia chaffeensis. About half of all adult ticks examined and approximately 20% of all nymphs were infected with Rickettsia species. In Ixodes ricinus ticks, Rickettsia helvetica and a Rickettsia species designated as IRS3 were found in high prevalence. Rickettsia conorii was found in virtually all non- Ixodes tick species from Albania and Turkey. The results of this study show that many tick-borne diseases are most probably endemic in the Balkan area. Furthermore, the results suggest that there is a considerable chance for simultaneous transmission of tick-borne pathogens to human beings.

Prevalence of four species of Borrelia burgdorferi sensu lato and coinfection with Anaplasma phagocytophila in Ixodes ricinus ticks in central Germany

A total of 305 Ixodes ricinus ticks collected from three areas of Thuringia in central Germany were investigated for infection with Borrelia burgdorferi sensu lato species and Anaplasma phagocytophila. Overall, 11.1% were infected with Borrelia burgdorferi and 2.3% with Anaplasma phagocytophila. Adult ticks showed a significantly higher rate of infection with both borreliae and Anaplasma phagocytophila. Borrelia garinii (55.9%) was detected most frequently, followed by Borrelia burgdorferi sensu stricto (32.4%), Borrelia afzelii (17.6%), and Borrelia valaisiana (5.9%). Four ticks had dual infection with Borrelia garinii and Borrelia burgdorferi sensu stricto. Two of the Borrelia-positive ticks were coinfected with Anaplasma phagocytophila.

Introduction of the exotic tick Amblyomma hebraeum into Florida on a human host

A resident of Florida returned from a short visit to southern Africa to find a male Amblyomma hebraeum tick attached to the skin behind her knee. Amblyomma hebraeum is a major vector of 2 pathogens that cause important diseases in southern Africa, heartwater of ruminants and African tick-bite fever of humans. The tick was tested by polymerase chain reaction assay for evidence of infection with Cowdria ruminantium and Rickettsia africae (the causative agents of heart-water and African tick-bite fever, respectively) and was found to be negative for both agents. This is the second record of the exotic tick, A. hebraeum, being introduced into the United States on a human host.

Ticks from a Morelet's crocodile in Belize

Parasitism of crocodilians by ticks has rarely been reported, and to our knowledge only seven published accounts exist. On 3 July 1999, we collected four ticks from a subadult Morelet's crocodile (Crocodylus moreletii) captured in northern Belize. These were identified as Amblyomma dissimile (one female), and Amblyomma sp. (two nymphs, one larva). The crocodile was captured on land approximately 100 m from water, and all four ticks were attached to loose skin on the lateral surface of the tail. Crocodilians are most susceptible to terrestrial ectoparasites, including ticks, during overland movements. However, most such movements occur in response to drought, when tick questing activity is suppressed, which likely accounts for the small numbers of tick specimens recorded from crocodilians and the absence of any noticeable impact of parasitism on host fitness.

Amblyomma testudinarium tick bite: one case of engorged adult and a case of extraordinary number of larval tick infestation

This paper reports two recent cases of tick bite due to Amblyomma testudinarium. The first case was an 86-year-old farmer infested with a fully engorged adult tick attached on his inguinal region. The second case was a 57-year-old male infested with an extraordinarily large number of larval ticks (> 100 larvae). The ticks were identified as A. testudinarium based on morphological characteristics. To our knowledge, the latter case is the eleventh case of larval tick bites among all tick species and the fourth case with larval A. testudinarium in Japan.

Purification, N-terminal sequencing and diagnostic value of the major antigens of Ornithodoros erraticus and O. moubata

To enhance the specificity and sensitivity of serological detection of swine exposed to Ornithodoros erraticus or O. moubata, we purified the 158, 186, 215 and 260 kDa antigens from the former species and the designated (owing to their MW and charge) 19C, 17A, 20A1 and 20A2 antigens of the latter by HPLC and gel electroelution methods. All the O. erraticus antigens share epitopes and are difficult to purify individually by reverse phase and ion-exchange chromatography due to their molecular similarity. Tested individually by ELISA, all of them give the same optical densities (OD) with anti-O. erraticus sera, and these ODs are always lower with anti-immature than with anti-adult sera. Although immature and adult specimens have the same antigens, immature forms induce more anti-carbohydrate antibodies than adults. This is the reason for the lower ODs of the anti-immature sera against purified antigens, since these latter antigens essentially react with anti-peptide antibodies (hence, increasing the specificity and sensitivity of the serology). The N-terminus of the 260 kDa antigen shows 80-90% similarity with the hemoglobin alpha-chain of many mammals. The antigens of O. moubata are proteins that are very different from one another and are, therefore, readily purified by ion exchange chromatography. The 20A1 antigen appears to be the most immunogenic and is recognized equally by anti-immature and anti-adult sera. This antigen does not give false positive reactions with the negative control sera analyzed and its N-terminus region shares 46.2% homology with the alpha-chain of the C3 component of rabbit complement.

[Ehrlichia canis infections of dogs in Germany. Epidemiology, diagnosis, therapy and prophylaxis]

Between January and December 1997 infections with Ehrlichia canis were detected in 211 dogs in Germany. Of the 53 epidemiologically evaluable dogs, 19 animals born and raised in Germany had travelled with their owners abroad in endemic areas, 30 dogs originated from there and four dogs had never left Germany. As regards to the possible location of infection it has been registered that most dogs had been taken to countries of the Mediterranean Sea (Spain, France, Italy, Greece) or had been imported from there. On inquiry, ticks had been forwarded from four dogs only, which were determined as Rhipicephalus sanguineus. The subsequent serological investigation of these four dogs revealed a Rickettsia conorii infection in two of them.

Antibody to a cDNA-derived calreticulin protein from Amblyomma americanum as a biomarker of tick exposure in humans

The antibody responses of human and animal hosts were studied to determine the utility of antibody against recombinant tick calreticulin (rTC), a cDNA-derived protein isolated from salivary glands of Amblyomma americanum L., as a biologic marker of tick exposure. Rabbits fed upon by either A. americanum or Dermacentor variabilis Say developed significant anti-rTC antibody responses, as measured by both ELISA and immunoblot assay. In contrast, gerbils exposed to Aedes aegypti did not develop anti-rTC antibodies, as measured by ELISA or immunoblot assay. The utility of the assay was next evaluated in humans at high risk for tick exposure. During April through September 1990, 192 military personnel who originated from either Fort Chaffee, Arkansas or Fort Wainwright, Alaska were studied during maneuvers in tick infested areas at Fort Chaffee. Study subjects completed a questionnaire and had pre- and post-maneuvers serum specimens analyzed for antibodies to rTC. In adjusted analysis (controlling for age, fort of origin, attached tick during maneuvers, and bed netting use), the use of bed netting and home station were associated with post-maneuvers anti-rTC antibody seropositivity by ELISA. Subjects from Fort Wainwright were more likely to be seropositive for anti-rTC antibody (adjusted odds ratio = 5.3, 95% confidence interval [CI] = 1.1-25.6). Personnel who did not report the use of bed netting were more likely to be anti-rTC seropositive (adjusted odds ratio = 6.8, 95% CI = 1.4-32.4). Immunoblot assays showed that humans had specific anti-rTC antibody responses. The animal experiments demonstrate that hosts exposed to naturally feeding ticks develop anti-rTC antibodies. The data also indicate that hosts exposed to Ae. aegypti saliva may not develop antibodies against rTC. Observations in tick-exposed humans support the hypothesis that anti-rTC antibody seropositivity is a biologic marker of tick exposure.

Antigens of interest for the diagnosis of parasitism in pigs by Ornithodoros erraticus and Ornithodoros moubata

We show by sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot that the composition of the soluble extracts of salivary glands (SGE-2) of Ornithodoros erraticus and Ornithodoros moubata is similar to that of the saliva (pilocarpine-induced), and that the extracts are a valid source of antigens for the detection of anti-argasid antibodies. It is also shown that the SGE-2s do not vary qualitatively with the developmental stage, physiological status, or sex of the ticks. The antigenic components (at least in O. erraticus) are released into the SGE-2 by the action of enzymes that can be inhibited by phenylmethane sulfonyl fluoride plus EDTA. Most of the components of the SGE-2, except the antigenic ones, are strongly glycosylated. Accordingly, the deglycosylation of the SGE-2s does not affect the recognition of antigenic components by anti-tick sera. In both species, the major components of the SGE-2s or the saliva are not recognized by the corresponding antisera. These nonimmunogenic components could have vaccinal value but not diagnostic interest. Finally, it is shown that the antigens of O. erraticus and O. moubata do not cross-react with one another and that those of the first species are more antigenic than those of the second.

Detection of pig farms with Ornithodoros erraticus by pig serology. Elimination of non-specific reactions by carbohydrate epitopes of salivary antigens

Ornithodoros erraticus is the European vector of African Swine Fever. It is therefore essential to know on which pig farms the tick is present in order to prevent contact with swine. Currently, studies are being made to ascertain this through the detection of anti-O. erraticus antibodies in the sera of swine, using three extracts from the salivary glands of the parasite (SGE): a complete extract (SGE-1), a soluble antigens extract (SGE-2), and a tissue antigens extract (SGE-3). The results of the present work show that SGE-2 gives the best differentiation between swine bitten by O. erraticus and unbitten swine in the enzyme-linked immunosorbent assay (ELISA). Using this extract, an optical density (OD) five-fold higher than the basal OD indicates that the pigs carry anti-O. erraticus antibodies. A serological study carried out in Salamanca with 8083 sera from 1756 pig farms revealed the presence of the parasite on 135 farms. However, during this study we noticed that some sera of unbitten animals gave false-positive reactions. Western blot analysis of SGE-2 of these false-positive sera demonstrated the same bands (except for two) as the real anti-O. erraticus sera. We observed, in ELISA and Western blot analysis, that such false-positive sera only recognised carbohydrate epitopes on SGE-2. This reactivity disappeared on deglycosylated SGE-2 (SGE-2-P). Therefore, SGE-2-P is the antigen that confers the greatest specificity to serology. In this study it was also observed that the low levels of anti-O. erraticus antibodies found in some cases may be because the swine were bitten some months previously on a different farm or that the current farm harboured only a few specimens of O. erraticus, so pig-tick contact is unlikely and hence the pigs either only develop a primary response or the time between contacts is very long and the levels of antibodies fall. Since pigs could be bitten on a different farm, the presence of low levels of anti-O. erraticus antibodies in pig sera do not necessarily indicate the presence of the tick on the farm where sampling was carried out.