First serosurvey of Besnoitia spp. infection in wild European ruminants in Spain

Epidemiological characteristics of bovine besnoitiosis (Besnoitia besnoiti) in a beef cattle farm: a cross-sectional serological assessment

Background

Bovine besnoitiosis is an emerging disease caused by the protozoa Besnoitia besnoiti that can have a serious economic impact on affected farms. The fact that there is no effective vaccine nor treatment, along with the lack of consistent epidemiologic data, renders the implementation of preventive medicine and control strategies much harder.

Objectives

A cross-sectional serological assessment was performed to better understand the distribution and prevalence of this parasite in a large beef cattle farm in Portugal and to establish some epidemiological characteristics of besnoitiosis.

Methods

A random blood sampling of 450 animals from a farm that keeps around 2,000 cattle head was performed and sera were submitted to an indirect immunofluorescent antibody test (IFAT). Data on breed, age, sex, and birthplace of the tested animals and their mothers were recorded.

Results

The overall prevalence of positive animals was 16.89%, with significant differences between under 1-year-old calves (4.8%) and adults (19.67%). A higher antibody prevalence was shown in animals 1-2 years and >7 years old, in Salers breed and in cows imported from France or whose mothers had come from this country. Calves under 1 year old and crossbreed animals with ancestry born in the current farm presented the lowest antibody prevalence.

Discussion and conclusions

The most significant risk factors revealed were age (>7 years old) and breed (Salers). Genetic studies should be carried out in order to confirm whether indeed there is a breed susceptibility to bovine besnoitiosis. We suggest that similar studies should be performed across southern Europe to establish strong epidemiologic data that would allow a rigorous transnational control program to be launched.

Molecular survey of Besnoitia spp. (Apicomplexa) in faeces from European wild mesocarnivores in Spain

Numerous studies have unsuccessfully tried to unravel the definitive host of the coccidian parasite Besnoitia besnoiti. Cattle infections by B. besnoiti cause a chronic and debilitating condition called bovine besnoitiosis that has emerged in Europe during the last two decades, mainly due to limitations in its control associated with the absence of vaccines and therapeutical tools. Although the exact transmission pathways of B. besnoiti is currently unknown, it is assumed that the parasite might have an indirect life cycle with a carnivore as definitive host. Current lack of studies in wildlife might underestimate the importance of free-living species in the epidemiology of B. besnoiti. Thus, the aim of the present study is to assess the presence of Besnoitia spp. in free-ranging mesocarnivores in Spain. DNA was searched by PCR on faeces collected from wild carnivores as a first approach to determine which species could be considered as potential definitive host candidates in further research. For this purpose, a total of 352 faecal samples from 12 free-living wild carnivore species belonging to the Canidae, Felidae, Herpestidae, Mustelidae, Procyonidae and Viverridae families were collected in seven Spanish regions. PCR testing showed that Besnoitia spp. DNA was present in four faecal samples from red foxes collected in western Spain, an area with the greatest density of extensively reared cattle and associated with high incidence of bovine besnoitiosis in the country. To date, this is the first report of a B. besnoiti-like sequence (99.57% homology) from carnivore faeces in a worldwide context. Red foxes might contribute to the epidemiology of B. besnoiti, although further studies, mostly based on bioassay, would be needed to elucidate the accuracy and extent of these interesting findings.

Lytic cycle of Besnoitia besnoiti tachyzoites displays similar features in primary bovine endothelial cells and fibroblasts

BACKGROUND

Bovine besnoitiosis, caused by the cyst-forming apicomplexan parasite Besnoitia besnoiti, is a chronic and debilitating cattle disease that continues to spread in Europe in the absence of control tools. In this scenario, in vitro culture systems are valuable tools to carry out drug screenings and to unravel host-parasite interactions. However, studies performed in bovine target cells are scarce.

METHODS

The objective of the present study was to obtain primary bovine aortic endothelial cells (BAECs) and fibroblast cell cultures, target cells during the acute and the chronic stage of the disease, respectively, from healthy bovine donors. Afterwards, expression of surface (CD31, CD34 and CD44) and intracellular markers (vimentin and cytokeratin) was studied to characterize cell populations by flow cytometry. Next, the lytic cycle of B. besnoiti tachyzoites was studied in both target cells. Invasion rates (IRs) were determined by immunofluorescence at several time points post-infection, and proliferation kinetics were studied by quantitative PCR (qPCR). Finally, the influence of bovine viral diarrhea virus (BVDV) co-infection on the host cell machinery, and consequently on B. besnoiti invasion and proliferation, was investigated in BAECs.

RESULTS

Morphology and cytometry results confirmed the endothelial and fibroblast origins. CD31 was the surface marker that best discriminated between BAECs and fibroblasts, since fibroblasts lacked CD31 labelling. Expression of CD34 was weak in low-passage BAECs and absent in high-passage BAECs and fibroblasts. Positive labelling for CD44, vimentin and cytokeratin was observed in both BAECs and fibroblasts. Regarding the lytic cycle of the parasite, although low invasion rates (approximately 3-4%) were found in both cell culture systems, more invasion was observed in BAECs at 24 and 72 hpi. The proliferation kinetics did not differ between BAECs and fibroblasts. BVDV infection favoured early Besnoitia invasion but there was no difference in tachyzoite yields observed in BVDV-BAECs compared to BAECs.

CONCLUSIONS

We have generated and characterized two novel standardized in vitro models for Besnoitia besnoiti infection based on bovine primary target BAECs and fibroblasts, and have shown the relevance of BVDV coinfections, which should be considered in further studies with other cattle pathogens.

Besnoitia besnoiti seroprevalence in beef, dairy and bullfighting cattle in Catalonia (north-eastern Spain): A cross-sectional study

Besnoitia besnoiti is the causative agent of bovine besnoitiosis, a chronic and debilitating disease of cattle that recently re-emerged and seems to be spreading in Europe. A cross-sectional serological study was carried out in different cattle herds in Catalonia, north-eastern Spain, to determine the seroprevalence of B. besnoiti in the region. A total of 791 serum samples (beef cattle n = 338, dairy cattle n = 291; bullfighting cattle n = 162) were tested. Sera were first screened for antibodies against Besnoitia using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) applying a cut-off that was lower than that recommended by the manufacturer in order to reach highest sensitivity. Sera above the chosen cut-off of 15% positivity (PP) were further tested by the Indirect Fluorescent Antibody Test (IFAT) and respectively positive results were confirmed by a B. besnoiti tachyzoite-based immunoblot. A total of 504/791 (63.7%) sera showed ELISA values above the selected cut-off, and 91 of these samples also yielded positive results in IFAT (cut-off titre 1:200). By immunoblot, a positive result was obtained in 93.4% (85 out of the 91) of the IFAT-positive samples. Interestingly, all confirmed Besnoitia-seropositive cases corresponded exclusively to beef cattle from the Pyrenees area, resulting in a prevalence of 25.1% (85/338) at the animal level and of 46% (36/78) at the herd level in this cattle group. No specific antibodies against Besnoitia could be detected in dairy and bullfighting cattle. The obtained results suggested that Besnoitia infections are present in Catalonia, consequently, diagnosis of this parasitic infection should be included in the sanitary control and before trading and movement of animals.

Repurposing of commercially available anti-coccidials identifies diclazuril and decoquinate as potential therapeutic candidates against Besnoitia besnoiti infection

Repurposing of currently marketed compounds with proven efficacy against apicomplexan parasites was used as an approach to define novel candidate therapeutics for bovine besnoitiosis. Besnoitia besnoiti tachyzoites grown in MARC-145 cells were exposed to different concentrations of toltrazuril, diclazuril, imidocarb, decoquinate, sulfadiazine and trimethoprim alone or in combination with sulfadiazine. Drugs were added either just prior to infection of MARC-145 cells (0 h post infection, hpi) or at 6 hpi. A primary evaluation of drug effects was done by direct immunofluorescence staining and counting. Potential effects on the host cells were assessed using a XTT kit for cell proliferation. Compounds displaying promising efficacy were selected for IC₅₀ and IC₉₉ determination by qPCR. In addition, the impact of drugs on the tachyzoite ultrastructure was assessed by TEM and long-term treatment assays were performed. Cytotoxicity assays confirmed that none of the compounds affected the host cells. Decoquinate and diclazuril displayed invasion inhibition rates of 90 and 83% at 0 h pi and 73 and 72% at 6 h pi, respectively. The remaining drugs showed lower efficacy and were not further studied. Decoquinate and diclazuril exhibited IC₉₉ values of 100 nM and 29.9 μM, respectively. TEM showed that decoquinate primarily affected the parasite mitochondrium, whilst diclazuril interfered in cytokinesis of daughter zoites. The present study demonstrates the efficacy of diclazuril and decoquinate against B. besnoiti in vitro and further assessments of safety and efficacy of both drugs should be performed in the target species.

In vitro efficacy of bumped kinase inhibitors against Besnoitia besnoiti tachyzoites

Besnoitia besnoiti is an apicomplexan parasite responsible for bovine besnoitiosis, a chronic and debilitating disease that causes systemic and skin manifestations and sterility in bulls. Neither treatments nor vaccines are currently available. In the search for therapeutic candidates, calcium-dependent protein kinases have arisen as promising drug targets in other apicomplexans (e.g. Neospora caninum, Toxoplasma gondii, Plasmodium spp. and Eimeria spp.) and are effectively targeted by bumped kinase inhibitors. In this study, we identified and cloned the gene coding for BbCDPK1. The impact of a library of nine bumped kinase inhibitor analogues on the activity of recombinant BbCDPK1 was assessed by luciferase assay. Afterwards, those were further screened for efficacy against Besnoitiabesnoiti tachyzoites grown in Marc-145 cells. Primary tests at 5µM revealed that eight compounds exhibited more than 90% inhibition of invasion and proliferation. The compounds BKI 1294, 1517, 1553 and 1571 were further characterised, and EC₉₉ (1294: 2.38µM; 1517: 2.20µM; 1553: 3.34µM; 1571: 2.78µM) were determined by quantitative real-time polymerase chain reaction in 3-day proliferation assays. Exposure of infected cultures with EC₉₉ concentrations of these drugs for up to 48h was not parasiticidal. The lack of parasiticidal action was confirmed by transmission electron microscopy, which showed that bumped kinase inhibitor treatment interfered with cell cycle regulation and non-disjunction of tachyzoites, resulting in the formation of large multi-nucleated complexes which co-existed with viable parasites within the parasitophorous vacuole. However, it is possible that, in the face of an active immune response, parasite clearance may occur. In summary, bumped kinase inhibitors may be effective drug candidates to control Besnoitiabesnoiti infection. Further in vivo experiments should be planned, as attainment and maintenance of therapeutic blood plasma levels in calves, without toxicity, has been demonstrated for BKIs 1294, 1517 and 1553.

Advances in the diagnosis of bovine besnoitiosis: current options and applications for control

Bovine besnoitiosis, which is caused by the tissue cyst-forming intracellular parasite Besnoitia besnoiti, is a chronic and debilitating disease that is responsible for severe economic losses in the cattle raised under extensive husbandry systems. The absence of vaccines, treatments or a health scheme at local, national and international levels has led to a rapid spread of bovine besnoitiosis from western Europe towards eastern countries and northwards. Moreover, this parasitic disease is widely present in many sub-Saharan countries. Thus, bovine besnoitiosis should be included in the animal health scheme of beef cattle herds. Accurate diagnostic tools and common diagnostic procedures are mandatory in any control programme. Relevant advances have been made in this field during the last decade. Succeeding with accurate diagnosis relies on the technique employed and the antibody and parasite kinetics of the infection stage, which may notably influence control programmes and surveillance. Moreover, control programmes should be adapted to the epidemiological status of the disease, as the disease presentation in a herd has important implications for prospective control. Herein, we review the clinical disease presentation of bovine besnoitiosis and the correlation between its clinical course and laboratory parameters. We also provide an update on the available diagnostic tools, discuss their strengths and pitfalls, and provide guidelines for their use in control, surveillance and epidemiological studies. A rational control strategy is also recommended.

A new lyophilized tachyzoite based ELISA to diagnose Besnoitia spp. infection in bovids and wild ruminants improves specificity

Recent studies have reported that routinely used whole or soluble Besnoitia besnoiti tachyzoite (TZ) extract-based ELISAs potentially give rise to a high number of false-positive results, which may compromise control and the epidemiological studies of bovine besnoitiosis. Thus, western blot (WB) has been recommended as a confirmatory test. In the present study, a new ELISA test that employs lyophilized tachyzoites for the first time (BbSALUVET ELISA 2.0) was developed and validated with cattle sera (n=606) under a worst-case scenario. False positive and false negative, soluble TZ extract-based BbSALUVET ELISA 1.0 reactors were overrepresented, and WB was used as the reference test. One commercial test (PrioCHECK Besnoitia Ab 2.0, which employs whole TZ extract) and a recently developed membrane-enriched ELISA (APure-BbELISA) were also tested. The three ELISAs showed high AUC values (>0.9). However, the best diagnostic performance corresponded to the BbSALUVET ELISA 2.0 and the APure-BbELISA [(92% sensitivity (Se) and 98% specificity (Sp)] followed by PrioCHECK Besnoitia Ab 2.0 (88% Se, 98% Sp, and 4.5% doubtful results). In addition, the BbSALUVET ELISA 2.0 was validated with wild ruminant sera, and excellent performance (96% Se, 97% Sp, and 4% doubtful results) was obtained again. A different antigenic composition of the lyophilized tachyzoites, compared with whole or soluble tachyzoite extracts, may be responsible for the improved diagnostic performance. This study proposes the use of the BbSALUVET ELISA 2.0 in cattle prior to entry to herds free of the disease and in valuable samples prior to a selective culling without the need of a confirmatory Western Blot test in positive samples due to its excellent specificity.

A serosurvey of selected cystogenic coccidia in Spanish equids: first detection of anti-Besnoitia spp. specific antibodies in Europe

Background

Equine besnoitiosis, caused by Besnoitia bennetti, and equine protozoal myeloencephalitis (EPM), caused by Sarcocystis neurona and Neospora hughesi are relevant equine diseases in the Americas that have been scarcely studied in Europe. Thus, a serosurvey of these cystogenic coccidia was carried out in Southern Spain. A cross-sectional study was performed and serum samples from horses (n = 553), donkeys (n = 85) and mules (n = 83) were included. An in-house enzyme-linked immunosorbent assay (ELISA) was employed to identify a Besnoitia spp. infection and positive results were confirmed by an a posteriori western blot. For Neospora spp. and Sarcocystis spp., infections were detected using in-house ELISAs based on the parasite surface antigens N. hughesi rNhSAG1 and S. neurona rSnSAG2/3/4. Risk factors associated with these protozoan infections were also investigated.

Results

Antibodies against Besnoitia spp., Neospora spp. and Sarcocystis spp. infections were detected in 51 (7.1%), 46 (6.4%) and 20 (2.8%) of 721 equids, respectively. The principal risk factors associated with a higher seroprevalence of Besnoitia spp. were the host species (mule or donkey), the absence of shelter and the absence of a rodent control programme. The presence of rodents was the only risk factor for Neospora spp. infection.

Conclusions

This study was the first extensive serosurvey of Besnoitia spp. infection in European equids accomplished by two complementary tests and gives evidence of the presence of specific antibodies in these populations. However, the origin of the infection is still unclear. Further parasite detection and molecular genotyping are needed to identify the causative Besnoitia and Neospora species. Finally, cross-reactions with antibodies directed against other species of Sarcocystis might explain the positive reactions against the S. neurona antigens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1046-z) contains supplementary material, which is available to authorized users.

Absence of antibodies specific to Besnoitia spp. in European sheep and goats from areas in Spain where bovine besnoitiosis is endemic

Besnoitia besnoiti and B. caprae, which infect bovids (cattle and antelopes) and goats, respectively, are responsible for besnoitiosis, a chronic and debilitating disease. Bovine besnoitiosis is considered to be a reemerging disease in Central and Western Europe. In addition, infection by Besnoitia spp. has been reported in reindeer from Sweden and Finland. Recently, the parasite was also detected in roe deer and red deer from Spain, where an interconnection between the domestic and sylvatic cycles of B. besnoiti has been presumed. In contrast, caprine besnoitiosis seems to be enzootic to Kenya and Iran. The presence of Besnoitia spp. in small domestic ruminants has never been explored in Europe, and the role that these species might play in the epidemiology of bovine besnoitiosis, as intermediate hosts or reservoirs of B. besnoiti, remains unknown. Herein, the first serosurvey conducted in European sheep and goats from areas in Spain where bovine besnoitiosis is endemic is described. Convenience sampling was conducted of 1943 sheep and 342 goats close to cattle from the Pyrenees and Central Spain that were infected with endemic Besnoitia spp. Serum samples were first analyzed by ELISA and then by confirmatory Western blot. Specific antibodies were not found in any sampled animal. Thus, sheep are unlikely to play a role in the epidemiology of bovine besnoitiosis, at least in the sampled areas. A larger serosurvey is necessary to determine whether goats might be a putative reservoir. To confirm the results of this study, sheep and goats should be further studied in other European countries and regions where their numbers are high and where bovine besnoitiosis is spreading.

Vector-borne transmission of Besnoitia besnoiti by blood-sucking and secretophagous flies: epidemiological and clinicopathological implications

Background

Bovine besnoitiosis has been recently diagnosed in a three-parted herd of 796 Aubrac and Charolais beef cattle in Hungary. A large scale serological, histological and molecular survey was initiated in order to uncover important factors in the local epidemiology of the disease.

Findings

Blood samples were collected (three times from the whole herd, and repeatedly from selected animals) for serological screening by ELISA. In addition, various organs from aborted fetuses and newborn calves, skin and colostrum samples of seropositive heifers/cows, and ticks collected from the cattle were histologically and/or molecularly analysed for the presence of Besnoitia besnoiti.

All fetal and calf tissues, as well as colostrum and tick samples from cows were PCR negative. Based on ELISA results, only very few local cows seroconverted after mating with imported, infected bulls, and not necessarily as a consequence of this event. Among calves that were born to seropositive, imported cows and stayed with their mother until weaning at seven months of age, seroprevalence decreased significantly, but remained high. At the same time, 28 calves born from seropositive cows, but separated from their dams immediately after receiving colostrum, were successfully reared and remained uninfected.

Following a second herd-level screening, all Aubrac cattle (except for heifer calves) and all seropositive Charolais cows and bulls were culled. Manifestation of the disease is currently sporadic. Among chronically affected heifers two types of skin lesions were noted, and histological evaluation indicated marked distension of sweat gland ducts with membrane-bound structures (resembling cystozoites) in their contents.

Conclusions

Transmission through natural mating, as well as transplacental, colostral and tick-borne transmission of B. besnoiti was either unlikely or did not occur. However, the risk for spreading of the infection was high, when calves stayed with their mother during suckling, and if animals were kept in the same stable (although physically separated) during the main fly season. Herd replacement and generation exchange (i.e. early weaning and artificial feeding) appear to be the successful strategies for the local eradication of bovine besnoitiosis. Adding to the already known mechanical transmission of B. besnoiti by blood-sucking flies, results of the present study suggest that secretophagous flies should also be evaluated as potential vectors of this coccidium species.

Besnoitia besnoiti among cattle in insular and northwestern Italy: endemic infection or isolated outbreaks?

BACKGROUND

Bovine besnoitiosis, caused by the apicomplexan Besnoitia besnoiti, is a chronic and debilitating disease considered as emerging in Europe. In Spain, Portugal and France it is endemic and foci of infection were recorded in Germany, Switzerland, Hungary, Greece and Italy. In Italy, cases of bovine besnoitiosis were registered both in imported and autochthonous cattle, and mostly in central regions; high seroprevalence was also revealed by an epidemiological survey performed in the southern part of the country. Aiming to update information on the disease in northwestern and insular areas of Italy, where data on bovine besnoitiosis were missing, a serosurvey was designed for the present study.

METHODS

Three thousand one hundred and forty bovine blood samples from both dairy and beef farms (n = 126) were collected in northwestern regions (Lombardy, Piedmont and Liguria) and in the island of Sardinia. Samples were analyzed by a standardized in-house ELISA and those resulted positive were re-tested by Western Blot (WB) for confirmation. On results obtained by both ELISA and WB, apparent (AP) and true prevalence (TP) were calculated at individual and herd levels. Further, a panel of sera resulted positive to ELISA was analyzed by IFAT.

RESULTS

A total of 712 animals (AP = 22.7%; TP = 18.8%) and 109 farms (AP = 86.5%; TP = 88.2%) showed a positive reaction in ELISA. Only ten (AP = 0.3%; TP = 0%) specimens proceeding from five farms (AP = 3.9%; TP = 1.7%) from Lombardy were confirmed positive to the WB, corresponding to two Holstein Friesian cows and eight beef cattle. IFAT showed a low sensitivity (44.4%) scoring positive in only four samples out of 9 positive to WB.

CONCLUSIONS

The survey demonstrated that bovine besnoitiosis cannot still be considered endemic in whole Italy. In fact, independent foci of infection were registered only in Lombardy region. Therefore, a sanitary strategy aimed to increase control measures and to organize monitoring plans, by adequate diagnostic tools is necessary to avoid overestimation of B. besnoiti in Italy.

Dynamics of Besnoitia besnoiti infection in cattle

Bovine besnoitiosis is caused by the cyst-forming apicomplexan parasite Besnoitia besnoiti. This disease progresses in two sequential phases: a febrile acute phase with oedemas and respiratory disorders, and a chronic phase characterized by the presence of subcutaneous tissue cysts and skin lesions. Serious consequences of the infection are poor body condition, sterility in bulls and eventual death. The role of host/parasite-dependent factors, which play a major role in the pathogenesis of the disease, is not yet fully elucidated. Isolate/strain virulence, parasite stage, dose and the route of parasite inoculation were studied under different experimental conditions, which make it difficult to compare the results. Data on host-dependent factors obtained from naturally infected cattle showed that (i) the seroprevalence of infection is similar in both sexes; (ii) seropositivity increases with age; (iii) both beef and dairy cattle are susceptible to the infection; and (iv) the cell-mediated immune response is likely to play a major role because a T cell response has been observed around several tissue cysts. Whether colostral antibodies are protective and to what extent the humoral immune response might reflect the disease/protection status require further research. Thus, a well-established experimental bovine model could help to clarify these important questions. The dynamics of B. besnoiti infection in cattle and available knowledge on relevant factors in the pathogenesis of the infection are reviewed in the present work.

No detection of Besnoitia besnoiti DNA in the semen of chronically infected bulls

Bovine besnoitiosis is a chronic and debilitating disease observed in many European countries that may cause important economic losses in cattle. The recent widespread of the parasite in Europe had led the European Food Safety Authority to declare bovine besnoitiosis as a re-emerging disease in Europe. Many aspects of the epidemiology of bovine besnoitiosis such as the main routes of transmission are still unclear and need to be further studied. Among the different hypotheses, a sexual transmission has not yet been investigated. Therefore, the aim of this study was to evaluate the presence of Besnoitia besnoiti DNA in the semen of naturally infected bulls by using a highly sensitive method (real-time qPCR). Both pre-sperm and sperm fractions of 40 bulls, including seronegative (n = 11), seropositive subclinically (n = 17), and seropositive clinically (n = 12) infected animals, were collected by electroejaculation and analyzed by real-time qPCR. No B. besnoiti DNA was detected in 27 pre-sperm and 28 sperm fractions of the 40 examined bulls, suggesting that the transmission of B. besnoiti infection by the semen of chronically infected bulls is very unlikely.

Insights from parasite-specific serological tools in eco-immunology

Eco-immunology seeks evolutionary explanations for the tremendous variation in immune defense observed in nature. Assays to quantify immune phenotypes often are crucial to this endeavor. To this end, we suggest that more use could (and arguably should) be made of the veterinary and clinical serological toolbox. For example, measuring the magnitude and half-life of parasite-specific antibodies across a range of host taxa may provide new ways of testing theories in eco-immunology. Here, we suggest that antibody assays developed in veterinary and clinical immunology and epidemiology provide excellent tools--or at least excellent starting points for development of tools--for tests of such hypotheses. We review how such assays work and how they may be optimized for new questions and new systems in eco-immunology. We provide examples of the application of such tools to eco-immunological studies of seabirds and mammals, and suggest a decision-tree to aid development of assays. We expect that addition of such tools to the eco-immunological toolbox will promote progress in the field and help elucidate how immune systems function and why they vary in nature.

A review on bovine besnoitiosis: a disease with economic impact in herd health management, caused by Besnoitia besnoiti (Franco and Borges, )

Bovine besnoitiosis is caused by the largely unexplored apicomplexan parasite Besnoitia besnoiti. In cows, infection during pregnancy often results in abortion, and chronically infected bulls become infertile. Similar to other apicomplexans B. besnoiti has acquired a largely intracellular lifestyle, but its complete life cycle is still unknown, modes of transmission have not been entirely resolved and the definitive host has not been identified. Outbreaks of bovine besnoitiosis in cattle were described in the 1990s in Portugal and Spain, and later several cases were also detected in France. More cases have been reported recently in hitherto unaffected countries, including Italy, Germany, Switzerland, Hungary and Croatia. To date, there is still no effective pharmaceutical compound available for the treatment of besnoitiosis in cattle, and progress in the identification of novel targets for intervention through pharmacological or immunological means is hampered by the lack of molecular data on the genomic and transcriptomic level. In addition, the lack of an appropriate small animal laboratory model, and wide gaps in our knowledge on the host-parasite interplay during the life cycle of this parasite, renders vaccine and drug development a cost- and labour-intensive undertaking.

Bovine besnoitiosis emerging in Central-Eastern Europe, Hungary

Background

Besnoitia besnoiti, the cause of bovine besnoitiosis, is a cyst-forming coccidian parasite that has recently been shown to be spreading in several Western and Southern European countries.

Findings

Clinical cases of bovine besnoitiosis were confirmed for the first time in Hungary, by histological, serological and PCR analyses.

Conclusions

This is the first report of autochthonous bovine besnoitiosis in Central-Eastern Europe. The emergence of bovine besnoitiosis in this region represents a further example, when human activity (i.e. cattle trading) is the main factor involved in the geographical spread of an infectious disease.

Blood-feeding patterns of horse flies in the French Pyrenees

Horse flies can mechanically transmit Besnoitia besnoiti, the agent of bovine besnoitiosis. Although previously limited to enzootic areas, especially the French Pyrenees Mountains, bovine besnoitiosis is now considered a re-emerging disease in western Europe. To improve understanding of the role of horse flies as mechanical vectors, this study investigated their blood-feeding ecology in the eastern French Pyrenees, in two high-altitude summer pastures whose main domestic ungulates were cattle, and in a wildlife park with native fauna. Species-specific PCR assays were conducted to identify the sources of blood meals: wild boar, horse, cattle (or bison), sheep (or mouflon), goat, red deer, roe deer and izard (or Pyrenean chamois). In La Mouline pasture, tabanids (N=20) fed on red deer (70%) and cattle (30%). In Mantet pasture, tabanids (N=24) fed on cattle (52%), red deer (20%), wild boar (16%), horse (8%) and sheep (4%). In the wildlife park, Tabanus bromius (N=32), the most abundant species collected, fed on red deer (85%), bison (9%) and wild boar (6%). Despite relatively high densities in both the pastures and in the wildlife park, small wild ungulates (izard, mouflon and roe deer) were not detected as a source of blood meals. Only two mixed blood meals were identified in two specimens of T. bromius: cattle/horse for the specimen collected in the pastures, and bison/wild boar for the specimen collected in the wildlife park. Our findings showed that tabanids display a level of opportunistic feeding behaviour, in addition to a preference for red deer, the latter being particularly true for Philipomyia aprica, the most abundant species collected in the pastures.