Another African disease in Central Europa: Besnoitiosis of cattle. I. Light and electron microscopical study

Mass Spectrometry Imaging of Lipid and Metabolite Distributions in Cysts of Besnoitia besnoiti-Infected Bovine Skin

Bovine besnoitiosis is a disease caused by the obligate intracellular parasite Besnoitia besnoiti. During its chronic stage, the parasite forms large, thick-walled cysts of up to 600 μm in diameter in the skin and other tissues. To assess an overview of parasite-induced metabolic changes during chronic infection, B. besnoiti-infected skin samples were analyzed by high-resolution atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI). Overall, infection-driven, significant changes of 467 lipids and metabolites were found in comparison to noninfected control samples. Most of them belong to the group of phosphatidic acids (PAs), phosphatidylserines (PSs), phosphatidylcholines (PCs)/phosphatidylethanolamines (PEs), triacylglycerides (TGs), phosphatidylinositols (PIs) and phosphatidylglycerols (PGs). When these quantitative data were combined with analyses on the lateral distribution of respective infection markers, MS images of significantly changed ion signals with specific lateral distributions were generated, matching with typical biological structures as observed in Hematoxylin and eosin (H&E)-stained tissue sections. Ultrahigh-resolution MALDI MSI with a pixel size of 2 μm and 3-dimensional reconstruction gave further insights into cyst construction.

First report of natural Besnoitia akodoni infection in synanthropic (Muridae) and wild (Cricetidae) rodents from Argentina

Besnoitia spp. are cyst-forming Apicomplexa parasites within the Sarcocystidae family. The objective of this study was to identify Besnoitia spp. in synanthropic (Muridae) and wild (Cricetidae) rodents from Argentina. Samples were collected from different organs and tissues of 356 rodents and examined by histopathological methods. Besnoitia cysts were detected by histopathology in 2 % (7/356) of the animals (i.e., two Mus musculus, two Necromys spp., two Oxymycterus rufus, and one Akodon azarae). The morphological diagnosis was molecularly confirmed by PCR and bidirectional sequencing of the ITS1 marker and flanking regions. The complete ITS1 region was identical in all seven samples, exhibiting 100 % identity with Besnoitia akodoni (AY545987). In addition, further characterization of the isolates targeting 18S rRNA and CoxI gene fragments was performed. Five identical 18S rRNA consensus sequences were amplified, which matched 100 % with Besnoitia sp. from Abrothrix hirta (Chile; OR052141) and B. jellisoni (AF291426) sequences. Besides, three CoxI consensus sequences were obtained from three different rodent species. These were identical among them and showed 92.88-92.93 % similarity to sequences from Besnoitia besnoiti uncharacterized protein (XM_029362743, among others). This is the first study to identify B. akodoni in naturally infected murid (Mus musculus) and cricetid (Necromys spp., Oxymycterus rufus, and A. azarae) rodents from Argentina, using both histopathological and molecular assessment. Further research is necessary to elucidate the significance of this parasite in rural ecosystems in our country.

Apicomplexa micropore: history, function, and formation

The micropore, a mysterious structure found in apicomplexan species, was recently shown to be essential for nutrient acquisition in Plasmodium falciparum and Toxoplasma gondii. However, the differences between the micropores of these two parasites questions the nature of a general apicomplexan micropore structure and whether the formation process model from Plasmodium can be applied to other apicomplexans. We analyzed the literature on different apicomplexan micropores and found that T. gondii probably harbors a more representative micropore type than the more widely studied ones in Plasmodium. Using recent knowledge of the Kelch 13 (K13) protein interactome and gene depletion phenotypes in the T. gondii micropore, we propose a model of micropore formation, thus enriching our wider understanding of micropore protein function.

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.

An update on epidemiology and clinical aspects of besnoitiosis in livestock and wildlife in sub-Saharan Africa: A systematic review

Besnoitiosis is a parasitic disease of economic importance caused by cyst-forming protozoa from the genus Besnoitia. The disease affects the skin, subcutis, blood vessels, and mucous membranes of the animals. It is traditionally endemic in the tropical and sub-tropical regions of the world, and causes enormous economic loss associated with impaired productivity and reproduction, as well as skin lesions. Therefore, knowledge of the epidemiology of the disease, including the current Besnoitia species occurring in sub-Saharan Africa, the wide range of mammalian species hosts they use as intermediate hosts, and the clinical signs manifested by infected animals is crucial in developing effective prevention and control measures. This review collected information from peer-reviewed publications involving the epidemiology and clinical signs of besnoitiosis in sub-Saharan Africa using four electronic databases. Results showed that B. besnoiti, B. bennetti, B. caprae, B. darlingi-like and unidentified Besnoitia spp. were found naturally infecting livestock and wildlife across nine reviewed sub-Saharan African countries. Besnoitia besnoiti was the most common species, occurring in all nine reviewed countries, and utilised a wide range of mammalian species as intermediate hosts. Prevalence of B. besnoiti ranged from 2.0 to 80.3%, and B. caprae 5.45-46.53%. Infection rate was high with serology compared to other techniques. Some of the typical signs of besnoitiosis included sand-like cysts on the sclera conjunctiva, nodules in the skin, thickening and wrinkling of the skin and alopecia. Inflammation, thickening and wrinkling of the scrotum were observed in bulls, and lesions on the scrotum deteriorated progressively and became generalized in some cases in spite of treatment. There is still a need for surveys focusing on detecting and identifying Besnoitia spp. using molecular techniques in combination with serological, histology and visual observation, and scoping their natural intermediate and definitive hosts, as well as assessing the burden of the disease animals reared on different husbandry systems in sub-Saharan Africa.

First Expert Elicitation of Knowledge on Drivers of Emergence of Bovine Besnoitiosis in Europe

Bovine besnoitiosis (BB) is a chronic and debilitating parasitic disease in cattle caused by the protozoan parasite Besnoitia besnoiti. South European countries are affected and have reported clinical cases of BB. However, BB is considered as emerging in other countries/regions of central, eastern and northern Europe. Yet, data on drivers of emergence of BB in Europe are scarce. In this study, fifty possible drivers of emergence of BB in cattle were identified. A scoring system was developed per driver. Then, the scoring was elicited from eleven recognized European experts to: (i) allocate a score to each driver, (ii) weight the score of drivers within each domain and (iii) weight the different domains among themselves. An overall weighted score was calculated per driver, and drivers were ranked in decreasing order of importance. Regression tree analysis was used to group drivers with comparable likelihoods to play a role in the emergence of BB in cattle in Europe. Finally, robustness testing of expert elicitation was performed for the seven drivers having the highest probability to play a key role in the emergence of BB: i.e., (i) legal/illegal movements of live animals from neighbouring/European Union member states or (ii) from third countries, (iii) risk of showing no clinical sign and silent spread during infection and post infection, (iv) as a consequence, difficulty to detect the emergence, (v) existence of vectors and their potential spread, (vi) European geographical proximity of the pathogen/disease to the country, and (vii) animal density of farms. Provided the limited scientific knowledge on the topic, expert elicitation of knowledge, multi-criteria decision analysis, cluster and sensitivity analyses are very important to prioritize future studies, e.g., the need for quantitative import risk assessment and estimation of the burden of BB to evidence and influence policymaking towards changing (or not) its status as a reportable disease, with prevention and control activities targeting, firstly, the top seven drivers. The present methodology could be applied to other emerging animal diseases.

Emergence of Besnoitia besnoiti in Belgium

Bovine besnoitiosis is a cattle disease caused by a protozoan parasite called Besnoitia besnoiti. It is of serious economic concern to the cattle industry and also compromises animal welfare. For several years, it has been considered an emerging disease in some countries and regions located in the north of Europe far away from the known endemic areas in the south. This study describes the situation in the southern part of Belgium, where the parasite was recently introduced through imports of animals coming from departments of France where the disease was present. It details the detection of clinical cases as well as disease transmission features related to contacts during grazing and sales of infected cattle. A tracking and monitoring system was quickly set up and detected twelve outbreaks. Several cattle were controlled, but the lack of appropriate regulations weakens disease-management efforts. Hopefully, this predictable and silent introduction triggers the awareness of decision-makers about the need for an appropriate prevention and control policy, law enforcement, and the implementation of necessary measures to avoid bovine besnoitiosis becoming endemic in Belgium or other non-endemic countries. In addition, more proactive surveillance is required from authorities through threat analysis in the context of the risk of emergence or re-emergence of infectious animal diseases.

Serological dynamics and risk factors of Besnoitia besnoiti infection in breeding bulls from an endemically infected purebred beef herd

Bovine besnoitiosis has been deemed a re-emerging disease in Western Europe and considered endemic in Spain, Portugal, France and in some areas of Northern Italy. This report refers to an infection outbreak in a purebred beef herd from Northern Italy involving a large number of bulls. In October 2013, 544 animals were serologically tested with an in-house ELISA followed by a confirmatory Western blot to evaluate Besnoitia besnoiti seroprevalence. A year later, 461 animals were then serologically re-tested together with imported animals (n = 268). Overall, 812 animals were involved in the study. Histology and immunohistochemistry were performed on skin biopsies of suspected animals and several tissue samples from a slaughtered bull. In the first sampling, 100 animals were seropositive (18.4%); in the second sampling, prevalence increased up to 36.5%, with incidence calculated at 39.6%. The risk factor analysis revealed that the infection was associated with age (OR = 1.007) and sex, with males presenting a greater risk (OR = 2.006). In fact, prevalence values in bulls increased from 29.6 to 56.7%, with an incidence of infection of 53.3%. Moreover, mating with a seropositive bull enhanced infection risk for a seronegative cow (OR = 1.678). Clinical signs typical of bovine besnoitiosis were found in seven seropositive animals, with confirmation of B. besnoiti through histology and immunohistochemistry. The study outcomes confirm that bovine besnoitiosis is a disease with serious economic impact on beef cattle breeding, particularly on bulls in service. Good management practises such as clinical monitoring and serological testing of imported animals should be implemented to control its occurrence.

Does bovine besnoitiosis affect the sexual function of chronically infected bulls?

Bovine besnoitiosis is a reemerging disease in Europe. The clinically Besnoitia besnoiti infection in bulls is characterized by fever, nasal discharge, and orchitis in the acute phase and by scleroderma in the chronic phase. However, in many bulls, B besnoiti infection remains at a subclinical stage. Bull infertility is an economically relevant consequence of besnoitiosis infection. It is not clear, however, if semen quality returns to normal levels when infected animals have clinically recovered. The aim of this study was to examine the relationship between chronic besnoitiosis and bull sexual function in a region of eastern France, where the disease is reemerging, by comparing semen quality and genital lesions in 11 uninfected, 17 subclinically infected, and 12 clinically infected bulls. The presence of anti-B besnoiti antibodies was detected by Western blot test. Semen was collected by electroejaculation. Bulls clinically infected with B besnoiti showed significantly more genital tract alterations than uninfected or subclinically infected bulls. No relationship was evidenced between besnoitiosis infectious status and semen quality, whereas a significant relationship was noted between genital lesions and semen score. This means that in the absence of moderate to severe genital lesions, chronic bovine besnoitiosis is unlikely to alter semen quality. However, as the presence of infected animals could lead to spread of the disease, culling or separation of clinically infected bulls from the remaining healthy animals is strongly recommended.

Besnoitia besnoiti infections activate primary bovine endothelial cells and promote PMN adhesion and NET formation under physiological flow condition

Besnoitia besnoiti is an obligate intracellular and emerging coccidian parasite of cattle that mainly infects host endothelial cells during acute infection. We here analyzed early innate immune reactions of B. besnoiti-infected primary bovine umbilical vein endothelial cells (BUVEC). B. besnoiti infections significantly activated BUVEC since the gene transcripts of several adhesion molecules (P-selectin, intercellular adhesion molecule 1(ICAM-1)), chemokines (CXCL1, CXCL8, CCL5), and of COX-2 were significantly upregulated during in vitro infection. Overall, the highest upregulation of most transcripts was observed at 24 or 48 h post infection (p.i.). Enhanced adhesion molecule expression in infected host cells was confirmed by PMN adhesion assays being performed under physiological flow conditions revealing a significantly increased PMN adhesion on B. besnoiti-infected BUVEC layers at 24 h p.i. Furthermore, we were able to illustrate neutrophil extracellular traps (NETs) being released by PMN under physiological flow conditions after adhesion to B. besnoiti-infected BUVEC layers. The present study shows that B. besnoiti infections of primary BUVEC induce a cascade of pro-inflammatory reactions and triggers early innate immune responses.

Experimental infections of rabbits with proliferative and latent stages of Besnoitia besnoiti

Cattle besnoitiosis due to Besnoitia besnoiti is spreading across Europe and is responsible for severe economic losses in newly infected herds. Experimentally speaking, rabbits have been found to be susceptible to this parasite. The adaptation of B. besnoiti to rabbits may offer a new, easier and cheaper model of investigation for this disease. This study compared the virulence between tachyzoites and bradyzoites of B. besnoiti in rabbits. Eighteen New Zealand rabbits were allocated into three groups of six animals each. The rabbits from the control (group C), "tachyzoite" (group T) and "bradyzoite" (group B) groups were subcutaneously injected in the right flank with 66 μg of ovalbumin, 6.10(6) tachyzoites (125th passage on Vero cells) and 6.10(6) bradyzoites (collected from a natural infected cow) of B. besnoiti, respectively. Clinical follow-up and blood sampling for serological survey and qPCR were performed during 10 weeks until euthanasia. Molecular and immunohistochemistry examination was achieved on 25 samples of tissue per rabbit. Seroconversion occurred in group T without any clinical signs. Rabbits of group B exhibited a febrile condition (temperature above 40 °C from day 8 to day 11 following injection) with positive qPCR in blood. Cysts of B. besnoiti were found on skin samples and organs of rabbits from group B in tissue explored with threshold cycle (Ct) values below 30. These results suggest a higher virulence of bradyzoites in rabbits than Vero cell-cultivated tachyzoites. The proposed model could be used to assess the in vivo effectiveness of vaccine or drugs against cattle besnoitiosis.

Besnoitia besnoiti tachyzoites induce monocyte extracellular trap formation

Extracellular trap (ET) formation has been demonstrated as an important novel effector mechanism of polymorphonuclear neutrophils (PMN), eosinophils, mast cells and macrophages acting extracellularly against pathogens. In the present study, we show that tachyzoites of the emerging apicomplexan parasite Besnoitia besnoiti, that have recently been reported as potent inducers of PMN-derived ETosis, also trigger the release of ETs in an additional cell type, namely in monocytes. Fluorescence illustrations as well as scanning electron microscopy analyses (SEM) showed monocyte-promoted ET formation to be rapidly induced upon exposure to viable tachyzoites of B. besnoiti. Classical characteristics of ETs were confirmed by the co-localization of extracellular DNA with histones (H3) or myeloperoxidase (MPO) in parasite-entrapping structures. Monocyte-derived ETs were efficiently abolished by DNase I treatment and significantly reduced by treatments with inhibitors of MPO and NADPH oxidase, thus strengthening the key roles of reactive oxygen species (ROS) and MPO in monocyte ET formation. For comparative reasons, we additionally tested sporozoite stages of the closely related parasite Eimeria bovis for their capacity to induce monocyte-derived ETs and showed that these stages indeed induce ETs. To our best knowledge, we here report for the first time on monocyte ETs against the apicomplexan parasites B. besnoiti and E. bovis. Our results indicate that monocyte-triggered ETs may represent an important effector mechanism of the host early innate immune response against B. besnoiti and add a new cell type to the list of cells capable to release ETs.

Naturally acquired bovine besnoitiosis: histological and immunohistochemical findings in acute, subacute, and chronic disease

The pathogenesis of bovine besnoitiosis, a disease of increasing concern within Europe, is still incompletely understood. In this study, disease progression after natural infection with the causative apicomplexan Besnoitia besnoiti was monitored in histological skin sections of 5 individual female cattle over time. High-frequency skin sampling of 2 cattle with mild and 2 with severe acute, subacute, and chronic besnoitiosis, as well as from 1 animal during subclinical disease, enabled documentation from the beginning of the disease. Skin sections were stained with hematoxylin and eosin and Giemsa, periodic acid-Schiff reaction, and anti-Besnoitia immunohistochemistry. In all 4 clinically affected animals, tachyzoite-like endozoites could be detected for the first time by immunohistochemistry, and tissue cyst evolution was monitored. Besnoitiosis-associated lesions were not detected in the animal showing the subclinical course. Because of the inconsistency of the nomenclature of Besnoitia tissue cyst layers in the literature, a new nomenclature for B. besnoiti cyst wall layers is proposed: tissue cysts consist of a hypertrophied host cell with enlarged nuclei, an intracytoplasmic parasitophorous vacuole with bradyzoites, a sometimes vacuolated inner cyst wall, and an outer cyst wall in more developed cysts. Inner and outer cyst walls can be readily distinguished by using special stains. In 1 animal, extracystic B. besnoiti zoites were immunohistochemically detected during the chronic stage. At necropsy, the 2 severely affected cows displayed large numbers of B. besnoiti cysts in a variety of tissues, including the corium of the claws, contributing mainly to the development of chronic laminitis in these 2 cases.

Caprine besnoitiosis: an emerging threat and its relationship to some other infections of ungulates by Besnoitia species

Caprine besnoitiosis, caused by the cyst-forming protozoal apicomplexan Besnoitia caprae appears to be endemic in Kenya, Nigeria and Iran, but has yet to be detected in other parts of the world. The infection causes an important parasitic disease of goats in affected developing countries. Bovine besnoitiosis, is a widespread disease of cattle in Africa, Asia (but not Iran) and southern Europe. Recent epidemiological data confirm that the incidence and geographical range of bovine besnoitiosis in Europe is increasing, which is why growing attention has been given to the condition during the past decade. This paper reviews pertinent information on the biology, epidemiology, pathology, clinical signs, diagnosis and control of caprine besnoitiosis, together with its similarities to, and differences from, bovine besnoitiosis. The serious economic consequences of besnoitiosis on goat breeding and local meat and hide industries is also considered.

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.

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.

Frequency of antibodies against Besnoitia besnoiti in Brazilian cattle

Besnoitia besnoiti is a cyst-forming parasite that has been associated with economic losses in Africa and Europe. Besnoitiosis is considered as a re-emergent disease in the European continent. It is unknown whether cattle are exposed to B. besnoiti in the Americas, thus the aim of this study was to serologically investigate antibodies against B. besnoiti in a total of 2014 cattle serum samples from two states from Brazil. All samples were evaluated by IFAT and part of the positive sera was tested by Western blot (WB) using tachyzoites extracts under non-reducing condition. A total of 3.48% (70/2014) of the tested sera reacted positively by IFAT with titers of 200 (85.7%), 400 (10%) and 800 (4.3%). When 47 positive samples were assessed by WB a range of antigens from 7 to 206 kDa was recognized by the IFAT-positive sera. The results are suggestive of exposure of Brazilian cattle to B. besnoiti due to the titers (≥ 200) observed for some sera using IFAT. However, the antigens recognized by the IFAT-positive animals did not completely match with the WB patterns previously described by other working groups. It is possible that Brazilian cattle are exposed to B. besnoiti strains with different antigenic composition of those described in the European and African continent. Further studies are needed to confirm the presence of B. besnoiti or other Besnoitia species in Brazilian cattle.

Chronic bovine besnoitiosis: intra-organ parasite distribution, parasite loads and parasite-associated lesions in subclinical cases

Bovine besnoitiosis caused by Besnoitia besnoiti is a chronic and debilitating disease. The most characteristic clinical signs of chronic besnoitiosis are visible tissue cysts in the scleral conjunctiva and the vagina, thickened skin and a generally poor body condition. However, many seropositive animals remain subclinically infected, and the role that these animals may play in spreading the disease is not known. The aim of the present study was to assess the intra-organ parasite distribution, the parasite load and the parasite-associated lesions in seropositive but subclinically infected animals. These animals were seropositive at the time of several consecutive samplings, had visible tissue cysts in the past and, at time of slaughter, had detectable specific anti-Besnoitia spp. antibody levels, but they did not show evident clinical signs at culling. Thus, histopathological, immunohistochemical and molecular analyses of several samples from the respiratory tract, reproductive tract, other internal organs and skin from six cows were performed. The tissue cysts were located primarily in the upper respiratory tract, i.e., in the rhinarium and larynx/pharynx (four cows), followed by the distal genital tract (vulva/vagina) and the skin of the neck (three and two cows, respectively, out of the four cows with cysts in the respiratory tract). We were unable to detect any parasites in the two remaining cows. Cysts were associated with a significant non-purulent inflammatory infiltrate consisting predominantly of T lymphocytes and activated monocytes/macrophages in two cows. The parasite burden, estimated by quantitative real-time PCR, was very low. It is noteworthy that the only animal that showed a recent increase in the antibody titre had the highest parasite burden and the most conspicuous inflammatory reaction against the cysts. In conclusion, although these cows no longer displayed any visible signs of besnoitiosis, they remained infected. Therefore, cows without visible signs of disease may still be able to transmit the parasite.

Development of early tissue cysts and associated pathology of Besnoitia besnoiti in a naturally infected bull (Bos taurus) from South Africa

Besnoitia besnoiti is an apicomplexan that causes serious economic loss in cattle in many countries and the disease is now spreading in Europe. At least 2 phases of bovine besnoitiosis are recognized clinically. An acute febrile phase characterized by anasarca and necrosis of skin is associated with multiplication of tachyzoites in vascular endothelium; this phase is short-lived and rarely diagnosed. Chronic besnoitiosis characterized by dermal lesions is associated with the presence of macroscopic tissue cysts and is easily diagnosed. Here we report the development of early B. besnoiti tissue cysts in a naturally infected Hugenoot bull from South Africa. Tissue cysts were 10-70 μm in diameter, contained 1-12 bradyzoites, and were most numerous in the dermis, testicles, and pampiniform venous plexus. Amylopectin granules in bradyzoites stained red with periodic acid Schiff (PAS) reaction. Bradyzoites varied in size and in the intensity of PAS reaction (some were PAS-negative), some were plump, and others were slender. With immunohistochemical staining with Besnoitia oryctofelisi and bradyzoite-specific antibodies (BAG-1 made against Toxoplasma gondii bradyzoites), the staining was confined to parasites, and all intracystic organisms were BAG-1 positive. With Gomori's silver stain only bradyzoites were stained very faintly whereas the rest of the tissue cyst was unstained. Ultrastructurally many tissue cysts contained dead bradyzoites and some appeared empty. Unlike bradyzoites from mature cysts, bradyzoites in the present case contained few or no micronemes. These findings are of diagnostic significance. Ultrastructually host cyst cells had features of myofibroblasts, and immunohistochemistry using antibodies against MAC387, lysozyme, vimentin, Von Willebrand factor, and smooth muscle actin confirmed this. Polymerase chain reaction on DNA extracted from lymph node of the bull confirmed B. besnoiti diagnosis. Associated clinical findings, lesions, and histopathology are briefly presented. The bull died of nephrotic syndrome; anasarca in acute besnoitiosis due to protein-losing glomerulopathy is a finding not previously reported in cattle.

First cross-sectional serological survey on Besnoitia besnoiti in cattle in Italy

A cross-sectional serological survey was conducted to evaluate the prevalence of besnoitiosis in cattle farms located in a region of southern Italy. A geographical information system (GIS) was used in order to uniformly sample the bovine farms (n=88) throughout the entire region. Blood samples were collected from 528 autochthonous cattle and sera were tested for antibodies to Besnoitia besnoiti using an enzyme-linked immunosorbent assay test. The farm prevalence was 83.0% (73/88), and the individual animal prevalence was 44.1% (233/528). The availability of geo-referenced point or areal data on bovine besnoitiosis and the construction of prevalence maps by GIS are suggested for dissemination of information to veterinarians on this emerging infection in cattle.

Parasites in ungulates of Arctic North America and Greenland: a view of contemporary diversity, ecology, and impact in a world under change

Parasites play an important role in the structure and function of arctic ecosystems, systems that are currently experiencing an unprecedented rate of change due to various anthropogenic perturbations, including climate change. Ungulates such as muskoxen, caribou, moose and Dall's sheep are also important components of northern ecosystems and are a source of food and income, as well as a focus for maintenance of cultural traditions, for northerners. Parasites of ungulates can influence host health, population dynamics and the quality, quantity and safety of meat and other products of animal origin consumed by people. In this article, we provide a contemporary view of the diversity of nematode, cestode, trematode, protozoan and arthropod parasites of ungulates in arctic and subarctic North America and Greenland. We explore the intricate associations among host and parasite assemblages and identify key issues and gaps in knowledge that emerge in a regime of accelerating environmental transition.

Development of a protocol testing the ability of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) to transmit Besnoitia besnoiti (Henry, 1913) (Apicomplexa: Sarcocystidae)

Cattle besnoitiosis due to the cyst-forming coccidian parasite Besnoitia besnoiti has recently been reported in expansion in Europe since the end of the twentieth century. The B. besnoiti life cycle and many epidemiological traits are still poorly known. Hematophagous flies, including the worldwide-distributed Stomoxys calcitrans, could be mechanical vectors in the contamination of mouthparts after the puncture of cutaneous cysts or ingestion of infected blood. In this study, a protocol is presented to assess more deeply the role of S. calcitrans, reared in laboratory conditions, in parasite transmission. A preliminary trial showed that stable flies could transmit tachyzoites from bovine artificially parasite-enriched blood to B. besnoiti-free blood using glass feeders. Evidence of transmission was provided by the detection of parasite DNA with Ct values ranging between 32 and 37 in the blood recipient. In a second time, a B. besnoiti-infected heifer harboring many cysts in its dermis was used as a donor of B. besnoiti. An interruption of the blood meal taken by 300 stable flies from this heifer was performed. Immediately after the blood meal was interrupted, they were transferred to a glass feeder containing B. besnoiti-free blood from a non-infected heifer. Quantitative PCR and modified direct fluorescence antibody test (dFAT) were used to detect B. besnoiti DNA and entire parasites, respectively, in the blood recipient, the mouthparts, and the gut contents of S. calcitrans at two time intervals: 1 and 24 h after the interrupted blood meal. Parasite DNA was detected at both time intervals (1 and 24 h) in all samples (blood recipient, mouthparts, and gut contents of stable flies) while entire parasites by dFAT were only found in the abdominal compartment 1 h after the interrupted blood meal. Then, S. calcitrans were able to carry B. besnoiti from chronically infected cattle to an artificial recipient in the conditions of the protocol.

Investigation of an outbreak of besnoitiosis in donkeys in northeastern Pennsylvania

OBJECTIVE

To describe the clinical, endoscopic, and serologic features of an outbreak of besnoitiosis in 2 donkey operations in northeastern Pennsylvania and to report the outcome of attempted treatment of 1 naturally infected individual.

DESIGN

Observational study.

ANIMALS

29 donkeys (Equus asinus) in northeastern Pennsylvania.

PROCEDURES

Donkeys were examined for lesions suggestive of besnoitiosis in an outbreak investigation. Information was collected regarding the history and signalment of animals on each premises. Rhinolaryngoscopy was performed to identify nasopharyngeal and laryngeal lesions. Serum samples were collected for immunofluorescent antibody testing and immunoblotting for Besnoitia spp. Skin biopsy samples were obtained from 8 animals with lesions suggestive of besnoitiosis for histologic examination. Quantitative real-time PCR assay for Besnoitia spp was performed on tissue samples from 5 animals.

RESULTS

Besnoitiosis was confirmed in 6 of the 8 suspected cases. The most common lesion site was the nares, followed by the skin and sclera. Donkeys with clinical signs of disease had higher serum antibody titers and tested positive for a greater number of immunoblot bands than did donkeys without clinical signs of disease. All animals evaluated by PCR assay tested positive. Putative risk factors for disease included age and sex. Ponazuril was not effective at treating besnoitiosis in a naturally infected donkey.

CONCLUSIONS AND CLINICAL RELEVANCE

Knowledge of clinical and serologic features of besnoitiosis in donkeys will assist clinicians in the diagnosis and prevention of this disease in donkey populations. Besnoitiosis may be an emerging disease of donkeys in the United States.

Molecular pathology, taxonomy and epidemiology of Besnoitia species (Protozoa: Sarcocystidae)

Until recently, besnoitiosis has been a neglected disease of domestic animals. Now, a geographic expansion of the causing protozoan parasite Besnoitia besnoiti in livestock has been recognized and the disease in cattle is considered emerging in Europe. Bovine besnoitiosis leads to significant economic losses by a decline in milk production, sterility, transient or permanent infertility of bulls, skin lesions and increase of mortality in affected cattle population. Phylogenetically, the Besnoitia genus is closest related to the well studied and medically important protozoans, Toxoplasma gondii and Neospora caninum. In contrast, discriminative molecular markers to type and subtype large mammalian Besnoitia species (B. besnoiti, B. caprae, B. tarandi, B. bennetti) on a relevant level of species and strains are lacking. Similarly, these cyst-forming parasites may use two hosts to fulfill their life cycle, but this has not been proven for all large mammalian Besnoitia species yet. Most important though, the final hosts and transmission routes of these Besnoitia species remain mysterious. Here, we review aspects of parasite's pathology, speciation, phylogeny, epidemiology and transmission with a special focus on recent molecular studies of all to date known Besnoitia species. Using an integrated approach, we have tried to highlight some promising directions for future research.

Besnoitia besnoiti protein disulfide isomerase (BbPDI): molecular characterization, expression and in silico modelling

Besnoitia besnoiti is an apicomplexan parasite responsible for bovine besnoitiosis, a disease with a high prevalence in tropical and subtropical regions and re-emerging in Europe. Despite the great economical losses associated with besnoitiosis, this disease has been underestimated and poorly studied, and neither an effective therapy nor an efficacious vaccine is available. Protein disulfide isomerase (PDI) is an essential enzyme for the acquisition of the correct three-dimensional structure of proteins. Current evidence suggests that in Neosporacaninum and Toxoplasmagondii, which are closely related to B. besnoiti, PDI play an important role in host cell invasion, is a relevant target for the host immune response, and represents a promising drug target and/or vaccine candidate. In this work, we present the nucleotide sequence of the B. besnoiti PDI gene. BbPDI belongs to the thioredoxin-like superfamily (cluster 00388) and is included in the PDI_a family (cluster defined cd02961) and the PDI_a_PDI_a'_c subfamily (cd02995). A 3D theoretical model was built by comparative homology using Swiss-Model server, using as a template the crystallographic deduced model of Tapasin-ERp57 (PDB code 3F8U chain C). Analysis of the phylogenetic tree for PDI within the phylum apicomplexa reinforces the close relationship among B. besnoiti, N. caninum and T. gondii. When subjected to a PDI-assay based on the polymerisation of reduced insulin, recombinant BbPDI expressed in E. coli exhibited enzymatic activity, which was inhibited by bacitracin. Antiserum directed against recombinant BbPDI reacted with PDI in Western blots and by immunofluorescence with B. besnoiti tachyzoites and bradyzoites.

Serological response of cats to experimental Besnoitia darlingi and Besnoitia neotomofelis infections and prevalence of antibodies to these parasites in cats from Virginia and Pennsylvania

Besnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana ) and Southern Plains woodrats (Neotoma micropus) as intermediate hosts, respectively. Nothing is known about the prevalence of B. darlingi or B. neotomofelis in cats from the United States. Besnoitia darlingi infections have been reported in naturally infected opossums from many states in the United States, and B. neotomofelis infections have been reported from Southern Plains woodrats from Texas, but naturally infected cats have not been identified. The present study examined the IgG antibody response of cats to experimental infection (B. darlingi n  =  1 cat; B. neotomofelis n  =  3 cats). Samples from these cats were used to develop an indirect immunofluorescent antibody test (IFAT), which was then used to examine seroprevalence of IgG antibodies to tachyzoites of B. darlingi and B. neotomofelis in a population of domestic cats from Virginia (N  =  232 cats) and Pennsylvania (N  =  209). The serum from cats inoculated with B. darlingi or B. neotomofelis cross-reacted with each other's tachyzoites. The titers to heterologous tachyzoites were 1 to 3 dilutions lower than to homologous tachyzoites. Sera from B. darlingi- or B. neotomofelis-infected cats did not react with tachyzoites of Toxoplasma gondii or Neospora caninum or merozoites of Sarcocystis neurona using the IFAT. Antibodies to B. darlingi were found in 14% and 2% of cats from Virginia and Pennsylvania, respectively. Antibodies to B. neotomofelis were found in 5% and 4% of cats from Virginia and Pennsylvania, respectively. Nine cats from Virginia and 1 cat from Pennsylvania were positive for both.

An outbreak of bovine besnoitiosis in beef cattle born in central Italy

An outbreak of bovine besnoitiosis in three female, 15-18 months old beef cattle in central Italy is here described. All the animals were born in central Italy without any recent contact with imported animals. The animals were in poor body conditions and showed symptoms and clinical signs consistent with chronic besnoitiosis. The diagnosis was confirmed by histopathologic examinations of skin biopsies and whole body at necropsy, showing typical 50-100 μ cysts engulfing superficial dermis in skin and lamina propria in mucosae; lesions were confined to skin and respiratory mucosae, and cysts were not seen in any other tissue. Bovine besnoitiosis is rapidly spreading among European countries and in our case the affected animals were born in the farm and not recent admission was referred, so it is likely to consider this as an autoctone outbreak of the disease in Italy. This case, taken together with other recently reported ones, suggest to consider Italy among potentially endemic areas for bovine besnoitiosis.

Histopathologic and Ultrastructural Studies on Experimental Caprine Besnoitiosis

The distribution pattern and associated tissue reactions with progressive changes in Besnoitia caprae cysts were investigated in 6 experimentally infected 16- to 20-month-old male goats. Each goat was subcutaneously inoculated with approximately 13 × 108 B caprae bradyzoites. The animals were examined daily for development of clinical besnoitiosis, and skin biopsies from distal parts of the limbs were taken at weekly intervals. At 15, 30, 60, 120, 180, and 365 days postinfection (DPI), 1 goat was euthanized. Samples were collected at autopsy from various organs for histologic and ultrastructural studies. No cysts were seen in tissue sections on 15, 30, and 365 DPI, but large numbers were present at 60, 120, and 180 DPI in the skin of the distal limbs, scrotum, and ears, with fewer in the tongue, palate, sclera, testicles, and spermatic cord. No cysts were seen in the lungs, liver, kidneys, spleen, central nervous system, or lymph nodes. Cyst numbers peaked at 60 DPI, then declined from 120 to 180 DPI. Degenerated cysts were relatively rare at 60 DPI but more numerous at 180 compared with 120. A granulomatous reaction—predominantly characterized by macrophages, lymphocytes, and plasma cells—surrounded each degenerated cyst. All goats showed testicular tubular degeneration with little or no spermatogenic activity. The sizes of cysts and their wall thickness, with the size of bradyzoites and some of their organelles, exhibited progressive chronologic changes.

A longitudinal study of Besnoitia besnoiti infections and seasonal abundance of Stomoxys calcitrans in a dairy cattle farm of southwest France

Bovine besnoitiosis, caused by the cyst-forming apicomplexan Besnoitia besnoiti, is commonly reported in some restricted regions of South-Western Europe, and in larger regions of Africa and Asia. This infection is thought to be transmitted by blood feeding insects and is responsible for major economic losses in cattle production. A recent emergence in Europe, notified in the Centre of France, Spain and Germany, has attracted more attention to this disease. Clinical signs could appear in some animals; however, many infected cattle remain asymptomatic or show scleral-conjunctival cysts (SCC) only. Recent development of serological methods allows carrying out seroepidemiological field studies. In this respect, a long-term investigation was performed in a dairy cattle farm localized in an enzootic area of besnoitiosis of South-western France between March 2008 and May 2009. The objective was to estimate the seasonal pattern of B. besnoiti infections based on the presence of SCC and serology (ELISA and Western blot). In parallel, an entomological survey was conducted to describe population dynamics of Stomoxys calcitrans and Tabanidae species. The seroprevalence determined by Western blot in a cohort of 57 animals continuously present during the whole survey increased from 30% in March 2008 to 89.5% in May 2009 and was always higher than the prevalence based on clinically assessed SCC. New positive B. besnoitia seroconversions occurred throughout the year with the highest number in spring. In addition, many seroconversions were reported in the two months before turn-out and could be associated with a high indoors activity of S. calcitrans during this period.

Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti

Bovine besnoitiosis is an economically important disease in cattle caused by the protozoan parasite Besnoitia besnoiti, which occurs endemically in many countries of Africa and Asia and is spreading in Europe. Serological identification of subclinically infected cattle is important to avoid the introduction of infected animals into naive herds. Here we determine the sensitivity and specificity of the PrioCHECK(®) Besnoitia Ab, a serological test recently introduced into the European market. Analytical specificity was examined using sera from animals experimentally infected with parasites related to B. besnoiti (n=27). Three animals experimentally infected with Neospora caninum or Toxoplasma gondii showed inconclusive reactions in the ELISA (percent positivity relative to the positive control [PP] 10% ≤ 20%) while all other sera reacted negative (PP<10%). An estimate of the diagnostic specificity was obtained by analysing field sera from bovine herds without besnoitiosis but with abortion problems associated to N. caninum (n=403). The analysis revealed a specificity of 94.3% or 96.8% depending on the applied cut-off (PP 10% or 20%, respectively). Sensitivity was assessed with sera from 110 animals of a herd in Germany where clinical bovine besnoitiosis was first diagnosed in September 2008. A positive serological reference standard was defined regarding sera from animals as reference positive, if these animals had tested positive in at least two of a panel of three other serological tests (two different B. besnoiti immunoblots and one immunofluorescence antibody test) on both of two sampling dates, November 2008 and April 2009. A diagnostic sensitivity of 91.8% or 75.5% was determined for sera collected in November 2008 and a sensitivity of 82.7% or 50% for sera collected in April 2009 (cut-off PP 10% or PP 20%, respectively). The marked drop in sensitivity from November 2008 to April 2009 was predominantly observed in reference-positive cattle without clinical signs. We conclude that PrioCHECK(®) Besnoitia Ab is a valuable diagnostic tool to detect clinically infected animals. Thus it may be used to support control measures, e.g., for the separation of infected animals from the remaining herd to avoid a further transmission of the infection within the herd.

Bovine besnoitiosis: epidemiological and clinical aspects

Bovine besnoitiosis, due to the cyst-forming apicomplexan Besnoitia besnoiti, is widespread in Africa, in Asia and in the south of Europe. This infection leads to major economic losses in cattle production with a decrease in milk production, transient of definitive sterility of bulls and mortality. Since its emergence in Europe (Germany, Spain and Centre of France), more attention has been given to this infection during the last 10 years, including the recent development of serological methods for diagnosis. The life cycle of B. besnoiti remains a mystery: the definitive host is unknown and the transmission routes are poorly understood. B. besnoiti is thought to be transmitted mainly by hematophagous insects. This paper presents a review of what is currently known of the epidemiology of bovine besnoitiosis and the key manifestations of the disease. It highlights the urgent need for research programs to improve efficient and sustainable control methods.

Development and use of an indirect ELISA in an outbreak of bovine besnoitiosis in Spain

An indirect ELISA based on a soluble extract of Besnoitia besnoiti tachyzoites was developed and standardised. A set of positive and negative reference bovine sera were characterised using an immunofluorescence antibody test and Western blot. A cut-off with a relative index per cent of 8.1 was determined for equal sensitivity and specificity (100 per cent) by two-graph receiver operating characteristic analysis. Cross-reactions with other closely related Apicomplexan parasites were discarded. The standardised ELISA was then used during an outbreak of bovine besnoitiosis in a mountainous area of central Spain. The outbreak occurred in nine herds, and 358 animals that shared grazing lands during the summer season were affected. Clinical examination and blood sampling were carried out for all animals, and skin biopsies were obtained from animals with skin lesions. The confirmatory diagnosis was carried out by means of the indirect ELISA, together with the identification of tissue cysts by microscopy. Most of the animals were seropositive (90.5 per cent), but only 43 per cent of seropositive cattle developed clinical signs compatible with besnoitiosis. Additionally, a significant increase in seroprevalence and clinical signs was found to be associated with the increasing age of the animals, suggesting rapid horizontal transmission of the disease.

Besnoitia neotomofelis n. sp. (Protozoa: Apicomplexa) from the southern plains woodrat ( Neotoma micropus)

Certain species of the protozoan genus Besnoitia cause clinical disease in livestock and wildlife. In the present paper a new species, Besnoitia neotomofelis is described from the southern planes woodrat (Neotoma micropus). The parasite was detected by bioassay of woodrat tissues in outbred Swiss Webster mice in an attempt to isolate Toxoplasma gondii. Initially, the organism was misdiagnosed as T. gondii because it was highly pathogenic for mice and its tachyzoites resembled T. gondii tachyzoites. Further studies revealed that it differed structurally and biologically from T. gondii. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells, and in vivo in mice. Non-dividing, uninucleate tachyzoites were approximately 1 x 5 μm in size. Longitudinally-cut bradyzoites in tissue sections measured 1.5-1.6 x 7.7-9.3 μm. Tissue cysts were microscopic, up to 210 μm long, and were infective orally to mice. Cats fed tissue cysts shed unsporulated 13 x 14 μm sized oocysts. All mice inoculated with B. neotomofelis died of acute besnoitiosis, irrespective of the dose, and Norwegian rats became infected but remained asymptomatic. Entero-epithelial stages (schizonts, gamonts) were found in cats fed tissue cysts. Large (up to 40 x 50 μm) first-generation schizonts developed in the lamina propria of the small intestine of cats. A second generation of small sized (8 μm) schizonts containing 4-8 merozoites was detected in enterocytes of the small intestine. Gamonts and oocysts were seen in goblet cells of the small intestinal epithelium. Tachyzoites were present in mesenteric lymph nodes of cats. Phylogenetic analysis indicated that B. neotomofelis was related to other Besnoitia species from rodents, rabbits, and opossums. Besnoitia neotomofelis is distinct from the 3 other species of Besnoitia, B. wallacei, B. darlingi and B. oryctofelisi that utilize cats as a definitive host.

Comparative evaluation of immunofluorescent antibody and new immunoblot tests for the specific detection of antibodies against Besnoitia besnoiti tachyzoites and bradyzoites in bovine sera

Besnoitia besnoiti, an apicomplexan parasite causes economically important disease in cattle in many countries of Africa and Asia is re-emerging in Europe. Serological identification of infected cattle is important because introduction of these animals into naive herds seems to play a major role in the transmission of the parasite. We report new, simplified immunoblot-based serological tests for the detection of B. besnoiti-specific antibodies. Antigens were used under non-reducing conditions in the immunoblots, because reduction of the antigen with beta-mercaptoethanol diminished the antigenicity in both, tachyzoites and bradyzoites. Ten B. besnoiti tachyzoite and ten bradyzoite antigens of 15-45 kDa molecular weight were recognized by B. besnoiti infected cattle, but not or only weakly detected by cattle infected with related protozoan parasites, Neospora caninum, Toxoplasma gondii, Sarcocystis cruzi, Sarcocystis hominis, or Sarcocystis hirsuta. The sensitivity and specificity of B. besnoiti immunoblots were determined with sera from 62 German cattle with clinically confirmed besnoitiosis and 404 sera from unexposed German cattle including 214 sera from animals with a N. caninum-specific antibody response. Using a new scoring system, the highest specificity (100%) and sensitivity (90%) of the immunoblots were observed when reactivity to at least four of the ten selected tachyzoite or bradyzoite antigens was considered as positive. When a cut-off based on this scoring system was applied to both the tachyzoite- and the bradyzoite-based immunoblots, there was an almost perfect agreement with the indirect fluorescent antibody test with a titre of 200 as the positive cut-off. We identified and partially characterized 10 tachyzoite and 10 bradyzoite B. besnoiti antigens which may help to develop new specific and sensitive serological tests based on individual antigens and in the identification of possible vaccine candidates.

Pattern of recognition of Besnoitia besnoiti tachyzoite and bradyzoite antigens by naturally infected cattle

Bovine besnoitiosis is caused by the protozoan parasite Besnoitia besnoiti. Many recent cases have been described in different European countries, which may be indicative of expansion of the disease in the next few years. Many infected animals remain asymptomatic; therefore, serological tests are essential tools for diagnosis. The objective of the present work was to identify B. besnoiti tachyzoite and bradyzoite immunodominant antigens (IDAs). IDAs were recognised by SDS-PAGE under reducing conditions and Western blot analysis. Positive sera from symptomatic (n=18) and asymptomatic (n=18) cattle came from herds endemically infected by B. besnoiti and were confirmed positive by IFAT, whereas negative sera (n=4) came from besnoitiosis-free herds and were also confirmed negative by IFAT. Up to 28 tachyzoite antigens in the range of 8.5-190.8 kDa were recognised. Based on the frequency of recognition, six IDAs (14.2, 33, 37.1, 39.6, 46.3 and 190.8 kDa) were identified. The 37.1 kDa antigen was recognised by 100% of sera, usually as an intense band. On the other hand, 30 bradyzoite antigens in the range of 8.5-187.9kDa were detected. Seven bradyzoite IDAs (8.5, 15.1, 16.8, 19.0, 34.7, 38.6 and 124.4 kDa) were identified and two of them (15.1 and 16.8 kDa) were considered the most immunogenic ones. Additionally, sera from animals with clinical symptoms recognised a significantly higher number of bradyzoite antigens. Finally, significant cross-reactions with other closely related apicomplexan parasites were not detected. This is the first description of B. besnoiti bradyzoite antigens. In addition, the identification of tachyzoite and bradyzoite IDAs may be useful for the development of vaccines and diagnostic tools for differentiating between acute and chronic infections. Further proteomic studies are needed in order to identify stage-specific proteins.