First detection and molecular identification of Babesia gibsoni from Rhipicephalus sanguineus ticks

Babesia gibsoni was firstly identified in Rhipicephalus sanguineus ticks infested on dogs in Asia. A total of 1195 ticks collected from veterinary practitioners and pet clinics were examined for Babesia by nested-polymerase chain reaction assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. Babesia infection was detected in nymph, male and female ticks with an infection rate of 2.42%, 0.98% and 1.97%, respectively. Sequence and phylogenetic analysis revealed that these Babesia spp. were genetically affiliated to the same clades within the genospecies of B. gibsoni and B. vogeli, and can be discriminated from other genospecies of Babesia. Intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level in B. gibsoni (GD<0.011) compared with other genospecies of Babesia (GD>0.106) and out-group protozoa (GD>0.244). This study provides the first molecular evidence of B. gibsoni identified in nymphs of R. sanguineus ticks in Asia, and further confirms the detection of B. vogeli in nymphs and adults of R. sanguineus in northern Taiwan. The epizootiological significance of canine Babesia spp. transmitted by R. sanguineus tick needs to be further identified.

Screening for Babesia microti in the U.S. Blood Supply

BACKGROUND

Babesia microti, a tickborne intraerythrocytic parasite that can be transmitted by means of blood transfusion, is responsible for the majority of cases of transfusion-transmitted babesiosis in the United States. However, no licensed test exists for screening for B. microti in donated blood. We assessed data from a large-scale, investigational product-release screening and donor follow-up program.

METHODS

From June 2012 through September 2014, we performed arrayed fluorescence immunoassays (AFIAs) for B. microti antibodies and real-time polymerase-chain-reaction (PCR) assays for B. microti DNA on blood-donation samples obtained in Connecticut, Massachusetts, Minnesota, and Wisconsin. We determined parasite loads with the use of quantitative PCR testing and assessed infectivity by means of the inoculation of hamsters and the subsequent examination for parasitemia. Donors with test-reactive samples were followed. Using data on cases of transfusion-transmitted babesiosis, we compared the proportions of screened versus unscreened donations that were infectious.

RESULTS

Of 89,153 blood-donation samples tested, 335 (0.38%) were confirmed to be positive, of which 67 (20%) were PCR-positive; 9 samples were antibody-negative (i.e., 1 antibody-negative sample per 9906 screened samples), representing 13% of all PCR-positive samples. PCR-positive samples were identified all through the year; antibody-negative infections occurred from June through September. Approximately one third of the red-cell samples from PCR-positive or high-titer AFIA-positive donations infected hamsters. Follow-up showed DNA clearance in 86% of the donors but antibody seroreversion in 8% after 1 year. In Connecticut and Massachusetts, no reported cases of transfusion-transmitted babesiosis were associated with screened donations (i.e., 0 cases per 75,331 screened donations), as compared with 14 cases per 253,031 unscreened donations (i.e., 1 case per 18,074 unscreened donations) (odds ratio, 8.6; 95% confidence interval, 0.51 to 144; P=0.05). Overall, 29 cases of transfusion-transmitted babesiosis were linked to blood from infected donors, including blood obtained from 10 donors whose samples tested positive on the PCR assay 2 to 7 months after the implicated donation.

CONCLUSIONS

Blood-donation screening for antibodies to and DNA from B. microti was associated with a decrease in the risk of transfusion-transmitted babesiosis. (Funded by the American Red Cross and Imugen; ClinicalTrials.gov number, NCT01528449 .).

Transfected Babesia bovis Expressing a Tick GST as a Live Vector Vaccine

The Rhipicephalus microplus tick is a notorious blood-feeding ectoparasite of livestock, especially cattle, responsible for massive losses in animal production. It is the main vector for transmission of pathogenic bacteria and parasites, including Babesia bovis, an intraerythrocytic apicomplexan protozoan parasite responsible for bovine Babesiosis. This study describes the development and testing of a live B. bovis vaccine expressing the protective tick antigen glutathione-S-transferase from Haemaphysalis longicornis (HlGST). The B. bovis S74-T3B parasites were electroporated with a plasmid containing the bidirectional Ef-1α (elongation factor 1 alpha) promoter of B. bovis controlling expression of two independent genes, the selectable marker GFP-BSD (green fluorescent protein–blasticidin deaminase), and HlGST fused to the MSA-1 (merozoite surface antigen 1) signal peptide from B. bovis. Electroporation followed by blasticidin selection resulted in the emergence of a mixed B. bovis transfected line (termed HlGST) in in vitro cultures, containing parasites with distinct patterns of insertion of both exogenous genes, either in or outside the Ef-1α locus. A B. bovis clonal line termed HlGST-Cln expressing intracellular GFP and HlGST in the surface of merozoites was then derived from the mixed parasite line HlGST using a fluorescent activated cell sorter. Two independent calf immunization trials were performed via intravenous inoculation of the HlGST-Cln and a previously described control consisting of an irrelevant transfected clonal line of B. bovis designated GFP-Cln. The control GFP-Cln line contains a copy of the GFP-BSD gene inserted into the Ef-1α locus of B. bovis in an identical fashion as the HIGST-Cln parasites. All animals inoculated with the HlGST-Cln and GFP-Cln transfected parasites developed mild babesiosis. Tick egg fertility and fully engorged female tick weight was reduced significantly in R. microplus feeding on HlGST-Cln-immunized calves. Collectively, these data show the efficacy of a transfected HlGST-Cln B. bovis parasite to induce detectable anti-glutathione-S-transferase antibodies and a reduction in tick size and fecundity of R. microplus feeding in experimentally inoculated animals.

The cattle tick Rhipicephalus microplus is a hematophagous ectoparasite, responsible for the transmission of lethal parasites such as Babesia sp, limiting cattle production in tropical and subtropical regions of the world. There is an urgent emerging need for improved methods of control for these currently neglected tick and tick borne diseases. It is hypothesized that a dual attenuated-live vector vaccine containing a stably transfected tick antigen elicits protective immune responses against the parasite and the tick vector in vaccinated cattle. Live Babesia vaccines based on attenuated parasites are the only effective method available for preventing acute babesiosis. On the other hand, glutathione-S-transferase from Haemaphysalis longicornis (HlGST) is a known effective antigen against Rhipicephalus microplus, the most common vector for B. bovis. This study describes the development and testing of a transfected, B. bovis vaccine expressing HlGST against the tick R. microplus. A B. bovis clonal line designated HlGST-Cln expressing HlGST and GFP/BSD, and separately a control transfected B. bovis clonal line expressing only GFP/BSD was used to vaccinate calves in two independent experiments. All immunized calves developed mild babesiosis, and only calves immunized with the HlGST-Cln parasite line generated anti-HlGST antibodies. Tick egg fertility and fully engorged female tick weight were reduced significantly in R. microplus feeding on HlGST-Cln-vaccinated calves. Taken together, these data demonstrates the ability of transfected B. bovis to elicit antibodies against a heterologous tick antigen in cattle and to induce partial protection in the vaccinated animals against the cattle tick for the first time, representing a step toward the goal to produce a live vector anti-tick vaccine.

Genome-wide diversity and gene expression profiling of Babesia microti isolates identify polymorphic genes that mediate host-pathogen interactions

Babesia microti, a tick-transmitted, intraerythrocytic protozoan parasite circulating mainly among small mammals, is the primary cause of human babesiosis. While most cases are transmitted by Ixodes ticks, the disease may also be transmitted through blood transfusion and perinatally. A comprehensive analysis of genome composition, genetic diversity, and gene expression profiling of seven B. microti isolates revealed that genetic variation in isolates from the Northeast United States is almost exclusively associated with genes encoding the surface proteome and secretome of the parasite. Furthermore, we found that polymorphism is restricted to a small number of genes, which are highly expressed during infection. In order to identify pathogen-encoded factors involved in host-parasite interactions, we screened a proteome array comprised of 174 B. microti proteins, including several predicted members of the parasite secretome. Using this immuno-proteomic approach we identified several novel antigens that trigger strong host immune responses during the onset of infection. The genomic and immunological data presented herein provide the first insights into the determinants of B. microti interaction with its mammalian hosts and their relevance for understanding the selective pressures acting on parasite evolution.

Vertical Transmission of Babesia microti in BALB/c Mice: Preliminary Report

Babesia spp. (Apicomplexa, Piroplasmida) are obligate parasites of many species of mammals, causing a malaria-like infection- babesiosis. Three routes of Babesia infection have been recognized to date. The main route is by a tick bite, the second is via blood transfusion. The third, vertical route of infection is poorly recognized and understood. Our study focused on vertical transmission of B. microti in a well-established mouse model. We assessed the success of this route of infection in BALB/c mice with acute and chronic infections of B. microti. In experimental groups, females were mated on the 1st day of Babesia infection (Group G0); on the 28th day post infection (dpi) in the post- acute phase of the parasite infection (G28); and on the 90th and 150th dpi (G90 and G150 group, respectively), in the chronic phase of the parasite infection. Pups were obtained from 58% of females mated in the post-acute phase (G28) and from 33% of females in groups G90 and G150. Mice mated in the pre-acute phase of infection (G0) did not deliver pups. Congenital B. microti infections were detected by PCR amplification of Babesia 18S rDNA in almost all pups (96%) from the experimental groups G28, G90 and G150. Parasitaemia in the F1 generation was low and varied between 0.01-0.001%. Vertical transmission of B. microti was demonstrated for the first time in BALB/c mice.

Transfusion-Transmitted Babesiosis During Total Hip Arthroplasty

Babesiosis is a potentially life-threatening zoonotic disease that is endemic to the northeastern United States and increasing in prevalence worldwide. Transmitted by the same Ixodes tick responsible for Lyme disease, the intraerythrocytic parasite Babesia causes a wide range of clinical presentations--from asymptomatic carriage to a fulminant course with rapid deterioration. Symptoms typically present 1 to 6 weeks after inoculation, with the gradual onset of fatigue, malaise, weakness, and intermittent or sustained fever as high as 40.9°C. Severe cases are associated with parasitemia greater than 4%, alkaline phosphatase greater than 125 U/L, and white blood cell counts greater than 5×10(9)/L. Definitive diagnosis is made by microscopic examination of thin blood smears, polymerase chain reaction, and indirect immunofluorescent antibody testing. The increasing frequency of babesiosis paired with a lack of blood-donor screening assays poses a serious threat to the safety of the US blood supply. Although babesiosis is responsible for 3.6% of transfusion-related deaths, the Food and Drug Administration has yet to approve mandatory screening for the parasite in donated blood. Historically, transfusion-transmitted babesiosis has been thought to be isolated to the immunocompromised patient population. However, a recent case of transfusion-transmitted babesiosis in an immunocompetent patient following total hip arthroplasty is the first reported in the literature and may represent a growing risk to a far greater segment of the population than previously thought. This article summarizes the current state of transfusion-transmitted babesiosis and the detrimental impact of this infection on blood transfusion safety.

American Black Bears as Hosts of Blacklegged Ticks (Acari: Ixodidae) in the Northeastern United States

Ticks and whole blood were collected from American black bears (Ursus americanus Pallas) between October 2011 and October 2012 across four counties in northwestern New Jersey, an area where blacklegged ticks (Ixodes scapularis Say) and their associated tick-borne pathogens are prevalent. Adult American dog ticks (Dermacentor variabilis Say) were the most frequently collected tick species in late spring, whereas adult and nymphal blacklegged ticks were found in both the late spring and fall months. Additionally, for blacklegged ticks, we determined the quality of bloodmeals that females acquired from black bears compared with bloodmeals from white-tailed deer (Odocoileus virginianus Zimmerman), the most important host for the adult stage of this tick species. Measures of fecundity after feeding on each host species were not significantly different, suggesting that the bloodmeal a female blacklegged tick acquires from a black bear is of similar quality to that obtained from a white-tailed deer. These results establish the American black bear as both a host and quality bloodmeal source to I. scapularis. Thus, black bears may help support blacklegged tick populations in areas where they are both present. In addition, samples of black bear blood were tested for DNA presence of three tick-borne pathogens. Anaplasma phagocytophilum Foggie and Babesia microti Franca were found in 9.2 and 32.3% of blood samples, respectively. All blood samples were quantitative polymerase chain reaction-negative for Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt, & Brenner. Although circulating pathogens were found in blood, the status of black bears as reservoirs for these pathogens remains unknown.

A Virulent Babesia bovis Strain Failed to Infect White-Tailed Deer (Odocoileus virginianus)

Wildlife are an important component in the vector-host-pathogen triangle of livestock diseases, as they maintain biological vectors that transmit pathogens and can serve as reservoirs for such infectious pathogens. Babesia bovis is a tick-borne pathogen, vectored by cattle fever ticks, Rhipicephalus spp., that can cause up to 90% mortality in naive adult cattle. While cattle are the primary host for cattle fever ticks, wild and exotic ungulates, including white-tailed deer (WTD), are known to be viable alternative hosts. The presence of cattle fever tick populations resistant to acaricides raises concerns regarding the possibility of these alternative hosts introducing tick-borne babesial parasites into areas free of infection. Understanding the B. bovis reservoir competence of these alternative hosts is critical to mitigating the risk of introduction. In this study, we tested the hypothesis that WTD are susceptible to infection with a B. bovis strain lethal to cattle. Two groups of deer were inoculated intravenously with either B. bovis blood stabilate or a larval extract supernatant containing sporozoites from infected R. microplus larvae. The collective data demonstrated that WTD are neither a transient host nor reservoir of B. bovis. This conclusion is supported by the failure of B. bovis to establish an infection in deer regardless of inoculum. Although specific antibody was detected for a short period in the WTD, the PCR results were consistently negative at multiple time points throughout the experiment and blood from WTD that had been exposed to parasite, transferred into naïve recipient susceptible calves, failed to establish infection. In contrast, naïve steers inoculated intravenously with either B. bovis blood stabilate or the larval extract supernatant containing sporozoites rapidly succumbed to disease. These findings provide evidence that WTD are not an epidemiological component in the maintenance of B. bovis infectivity to livestock.

Vector ecology of equine piroplasmosis

Equine piroplasmosis is a disease of Equidae, including horses, donkeys, mules, and zebras, caused by either of two protozoan parasites, Theileria equi or Babesia caballi. These parasites are biologically transmitted between hosts via tick vectors, and although they have inherent differences they are categorized together because they cause similar pathology and have similar morphologies, life cycles, and vector relationships. To complete their life cycle, these parasites must undergo a complex series of developmental events, including sexual-stage development in their tick vectors. Consequently, ticks are the definitive hosts as well as vectors for these parasites, and the vector relationship is restricted to a few competent tick species. Because the vector relationship is critical to the epidemiology of these parasites, we highlight current knowledge of the vector ecology of these tick-borne equine pathogens, emphasizing tick transmissibility and potential control strategies to prevent their spread.

Functional genomics of tick vectors challenged with the cattle parasite Babesia bigemina

Ticks are obligate hematophagous ectoparasites considered as vectors of animal diseases, having a huge economic impact in cattle industry. Babesia spp. are tick-borne pathogens that cause a disease called babesiosis in a wide range of animals and in humans. Control of tick infestations is mainly based on the use of acaricides, which have limited efficacy reducing tick infestations, mostly due to wrong usage, and is often accompanied by the selection of acaricide-resistant ticks, environmental contamination, and contamination of milk and meat products. Vaccines affecting both vector and pathogens constitute new control strategies for tick and tick-borne diseases and are, therefore, a good alternative to chemical control. In this chapter we describe the identification of Rhipicephalus (Boophilus) annulatus genes differentially expressed in response to infection with B. bigemina by using suppression-subtractive hybridization (SSH), which allows the identification of differentially expressed genes. The results of the SSH studies are validated by real-time reverse transcription (RT)-PCR. Functional analyses are conducted by RNAi on selected R. annulatus genes to determine their putative role in B. bigemina-tick interactions. Gathered data may be useful for the future development of improved vaccines and vaccination strategies to control babesiosis.

[Parasitological factors impeding the transmission of the agent of babesiosis (Babesia microti) to man from the tick Ixodes persulcatus]

Based on the analysis of own and literature data, it is concluded that the following ma- in permanent system of ecologicalarasitological factors prevents the effective vector functions of the tick I. persulcatus in transmission of B. microti: lack of distinct nymphs' anthropophily; small spontaneous invasion of hungry adults; a duration of the parasitic phase in humans is insufficient to complete the sporogonic development, because victims interrupt the phase. Therefore, not excluding the possibility of sporadic babesiosis disea- ses, it can be stated that within the boundaries of a vast territory, where the taiga tick is the only potential source of infection for humans, the B. microti infection has not, and will not reach significant values in infectious pathology.

Co-transmission of the non-transmissible South African Babesia bovis S24 vaccine strain during mixed infection with a field isolate

The South African Babesia bovis live blood vaccine, originating from a field isolate attenuated by 23 serial syringe passages in splenectomized calves, has lost the ability to infect the natural vector Rhipicephalus (Boophilus) microplus. In this study, infection with mixed parasites from the vaccine strain and a field isolate, resulted in transmission of both genotype populations. Comparing the field isolate and transmitted combination indicated no significant difference in their virulence, while challenge of vaccinated cattle with these isolates showed the ability of the vaccine to protect against both. Limiting dilution of the transmitted combination, followed by infection of splenectomized cattle (n=34) yielded no single infections for the vaccine strain genotype, seven clonal lines of the field isolate and one mixture of vaccine strain and field isolate. Only one of two field isolate clonal lines selected for vector transmission study was transmitted. Showing that B. bovis isolates can contain both tick transmissible and non-transmissible subpopulations. The findings of this study also indicate the probability of vaccine co-infection transmission occurring in the field, which may result in new genotype populations of B. bovis. However, the impact of this recombination with field isolates is considered negligible since a genotypically diverse population of B. bovis is already present in South Africa.

Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens

Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management.

Co-infection of blacklegged ticks with Babesia microti and Borrelia burgdorferi is higher than expected and acquired from small mammal hosts

Humans in the northeastern and midwestern United States are at increasing risk of acquiring tickborne diseases--not only Lyme disease, but also two emerging diseases, human granulocytic anaplasmosis and human babesiosis. Co-infection with two or more of these pathogens can increase the severity of health impacts. The risk of co-infection is intensified by the ecology of these three diseases because all three pathogens (Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti) are transmitted by the same vector, blacklegged ticks (Ixodes scapularis), and are carried by many of the same reservoir hosts. The risk of exposure to multiple pathogens from a single tick bite and the sources of co-infected ticks are not well understood. In this study, we quantify the risk of co-infection by measuring infection prevalence in 4,368 questing nymphs throughout an endemic region for all three diseases (Dutchess County, NY) to determine if co-infections occur at frequencies other than predicted by independent assortment of pathogens. Further, we identify sources of co-infection by quantifying rates of co-infection on 3,275 larval ticks fed on known hosts. We find significant deviations of levels of co-infection in questing nymphs, most notably 83% more co-infection with Babesia microti and Borrelia burgdorferi than predicted by chance alone. Further, this pattern of increased co-infection was observed in larval ticks that fed on small mammal hosts, but not on meso-mammal, sciurid, or avian hosts. Co-infections involving A. phagocytophilum were less common, and fewer co-infections of A. phagocytophilum and B. microti than predicted by chance were observed in both questing nymphs and larvae fed on small mammals. Medical practitioners should be aware of the elevated risk of B. microti/B. burgdorferi co-infection.

Morphological characteristics and developmental changes of the ovary in the tick Haemaphysalis longicornis Neumann

Haemaphysalis longicornis (Ixodida: Ixodidae) is an important vector of transovarially transmitted parasites of the genus Babesia (Piroplasmida: Babesiidae). In the present study, we investigated the morphological characteristics and developmental changes of the ovary of H. longicornis. We show that the ovary of H. longicornis has a single tubular structure and is surrounded by a tunica propria. There is a longitudinal groove along one side of the ovary. During feeding and after engorgement, great changes can be observed in the ovary of H. longicornis and two rapid growth phases can be detected. The number of major protein bands of the ovary is significantly increased from day 3 of feeding and reaches a maximum on the day of engorgement. Therefore, the great diversity of proteins in the ovaries of H. longicornis can facilitate the identification of new targets for vaccine development.

The first evidence for vertical transmission of Babesia canis in a litter of Central Asian Shepherd dogs

INTRODUCTION AND OBJECTIVE

Tick-borne infections constitute an increasing health problem in dogs and may lead to death, especially in young or elderly individuals. Canine babesiosis constitutes a serious health problem in dogs worldwide. The aim of the study was to verify the probability of vertical transmission of Babesia canis between the bitch and the pups.

MATERIALS AND METHODS

In Autumn 2011, cases of babesiosis were diagnosed in a litter of 6-week-old puppies of a Central Asian Shepherd dog. Immediately following the first case of infection, blood samples were collected from all the pups in the litter (n=10) and from the female. Detection of Babesia infection was performed by molecular and microscopical techniques.

RESULTS

The presence of B. canis DNA was detected using PCR in three pups, presenting at the time or 24-48 hours later with babesiosis symptoms, and in their asymptomatic mother. The isolates derived from the pups and the female - 520 bp 18S rRNA gene fragment - were compared and analyzed. All isolates from the pups and their mother were identical and showed 100% homology with B. canis group B (EU622793), supporting the same source of infection. Additionally, the USG of the peritoneal cavity was performed in the female, presenting evidence for splenomegaly.

CONCLUSIONS

On the basis of (1) the same timing of three pup cases; (2) the identical B. canis sequences derived from all positive dogs; (3) evident splenomegaly in the asymptomatic female, this provides the first evidence of the vertical transmission of this piroplasm in dogs.

JapaneseBabesia microtiCytologically Detected in Salivary Glands of Naturally Infected TickIxodes ovatus

Babesia microti protozoa were detected by light and electron microscopy in the salivary glands of field-collected Ixodes ovatus ticks; 6 of 85 adult ticks were demonstrated to be positive for B. microti DNA by polymerase chain reaction assays. In the salivary glands of unfed ticks, B. microti existed in the sporoblast stage in the granular acinus cells, and developed into the sporozoite stage during feeding on the host for 2 days. The present results indicated for the first time that I. ovatus can indeed carry B. microti and is not infected mechanically with the parasites by blood-sucking. This frequent infection of I. ovatus with B. microti demonstrates the significance of such a vector-pathogen relationship in Japan, and strongly suggests that I. ovatus is involved in the maintenance of B. microti in the fauna of Japanese rodents.

Piroplasmen der Wiederkäuer in der Schweiz und zoonotische Bedeutung der Babesien

Piroplasms are tick-transmitted blood parasites belonging to the genera Babesia and Theileria. In western and southern Switzerland, B. divergens, a small Babesia species, has been known for a long time as a parasite of cattle. Recent investigations have revealed the autochthonous occurrence of this parasite also in central and eastern Switzerland. On the occasion of an outbreak of anaplasmosis in the canton of Grisons, however, B. bigemina, a large Babesia species, and Theileria of the buffeli/sergenti/orientalis species complex were for the first time identified; the epidemiology of these two piroplasms in Switzerland remains unknown until now. The recent identification by genetic analyses of B. divergens in wild ruminants contradicts the hitherto postulated strict host specificity of this Babesia species for cattle. B. divergens as well as the closely related Babesia spp. genotype EU1 have in single cases also been identified in splenectomized humans. The rodent babesia B. microti which causes a human infection that is considered an "emerging tick-borne disease" in the U.S.A., is widespread in rodent populations in Switzerland, but seems to be of minor relevance as zoonotic pathogen here. Reasons for this could be differences in virulence of the parasites or in the transmission by the respective tick-vectors on the two continents.

Prevention of transmission of Babesia canis by Dermacentor reticulatus ticks to dogs treated with an imidacloprid/flumethrin collar

A group of 8 dogs was treated with an imidacloprid/flumethrin collar (Seresto(®)) 28 days prior to infestation with adult Dermacentor reticulatus ticks, infected with Babesia canis. The ability of the collar to prevent transmission of B. canis in the treated group was compared to an untreated control group. All 8 dogs in the untreated control group became infected with B. canis parasites, which were detected in blood smears as early as day 6 post tick-application. All control dogs developed clinical signs of babesiosis and were rescue-treated with imidocarb dipropionate. These dogs also developed specific B. canis antibodies as identified by serology (IFA test) and were confirmed PCR/RLB positive. None of the 8 dogs treated with the imidacloprid/flumethrin collar became infected with B. canis, which was confirmed by the absence of specific B. canis antibodies and babesial DNA as confirmed by PCR/RLB. The collar caused 96.02% of the ticks to die within 48h post challenge and this increased to 100% within 4 days. Although a high percentage of 44% of the Dermacentor ticks were infected with B. canis, they were unable to transmit the infection to the treated group. Hence, the imidacloprid/flumethrin collar effectively prevented transmission of B. canis 1 month after application onto the dogs.

Babesiosis surveillance - 18 States, 2011

Babesiosis is caused by protozoan parasites of the genus Babesia that infect red blood cells. Babesia infection can range from asymptomatic to life threatening. Clinical manifestations might include fever, other nonspecific influenza-like symptoms, and hemolytic anemia. Babesia parasites in nature usually are tickborne but they also are transmissible via blood transfusion or congenitally. In recent years, reports of tickborne and transfusion-associated cases have increased in number and geographic distribution. However, the lack of a standard case definition hindered the ability of public health authorities to monitor cases and to develop evidence-based prevention and control measures. In January 2011, national surveillance for human babesiosis was begun in 19 jurisdictions (18 states and one city), using a standard case definition developed jointly by CDC and the Council of State and Territorial Epidemiologists. This report summarizes the results for 2011. For the first year of babesiosis surveillance, health departments notified CDC of 1,124 confirmed and probable cases. Cases were reported by 15 of the 18 states where babesiosis was reportable; however, 1,092 cases (97%) were reported by seven states (Connecticut, Massachusetts, Minnesota, New Jersey, New York [including New York City], Rhode Island, and Wisconsin). Cases were identified in persons aged <1-98 years; 57% were in persons aged ≥60 years. Among patients for whom data were available, 82% (717 of 879) had symptom onset dates during June-August. Ongoing national surveillance using the standard case definition will provide a foundation for developing evidence-based prevention and control measures to reduce the burden of babesiosis.

[The prevalence of Babesia canis canis in marsh ticks (Dermacentor reticulatus) in the Saarland]

An accumulation of autochthonous cases of canine babesiosis caused by Babesia canis has been registered in a small animal clinic in the Saarland since the beginning of 2006, some cases with fatal outcome. This study aims to contribute to the explanation of strong focal occurrence of infections with B. canis in this region.Therefore, patient owners who had presented their dogs in the years 2006 and 2007 because of babesiosis and who had claimed not having left the Saarland with their dogs at least six months before the outbreak of Babesiosis, were asked for their dog walking habits. Accordingly, a selection often tick collection sites of various landscape structures was made.Tick sampling by flagging the vegetation took place every month from March to December 2008. The collected ticks were identified morphologically. In eight of ten collecting sites a total of 397 adult Dermacentor reticulatus ticks were collected from March to December with the highest frequencies during the months of May, October and November. All collected specimens were examined by genus-specific conventional PCR for the presence of Babesia-DNA. In positive samples, the PCR-products were differentiated by sequencing. ten D. reticulatus (2.5%) ticks examined were found positive for DNA of B. canis canis originating from three out of eight collection sites. Consequently, an endemic distribution of D. reticulatus was confirmed and a natural

Simultaneous detection of piroplasma infections in field Haemaphysalis qinghaiensis ticks by reverse line blotting

Piroplasmosis is caused by tick-borne haemoprotozoan parasites in the genera of Theileria and Babesia, in which numbers of agents are highly pathogenic for cattle, sheep and goats. We developed a reverse line blot (RLB) assay for detection and differentiation of four different parasites, in which 18S ribosomal RNA gene sequence was amplified with a set of universal primers specific for all members in the genera of Theileria and Babesia; and the probes were designed on the basis of hypervariable region 4 (V4 region) of 18S rRNA gene. Three Theileria and one Babesia can be detected simultaneously on this system and it was sensitive to detect a parasitemia level between 10(-5) and 10(-8)%. A total of 149 Haemaphysalis qinghaiensis ticks collected from Lintan County of Gannan Tibetan Autonomous Region was tested by RLB. Among these, 136 tick samples were also tested by a nested PCR assay developed previously. After comparison of these results, it showed that more T. luwenshuni was detected in RLB assay, while more T. uilenbergi was detected in H. qinghaiensis ticks by nested PCR. The RLB has shown capability for simultaneous detection of four species of piroplasm in H. qinghaiensis ticks, indicating its usefulness for epidemiological studies of piroplasmosis.