Review on trypanosomiasis and their prevalence in some country on the Red Sea / Avaliação da tripanossomíase e sua prevalência em alguns países do mar Vermelho

Trypanosomiasis is a protozoan infection affecting both human and animals in almost all parts of the world. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles and elephants. This review paper was designed to address the effect of this economically important disease in countries on the Red Sea, especially in Egypt, Sudan, Somalia, and Saudi Arabia during the period 2010 to 2020. The prevalence of trypanosomiasis is different between these countries due to different types of diagnostic methods (Giemsa-stained blood smears, Hematocrit centrifugation, Serological test, and molecular analysis PCR) used and differential distribution of vector (Tse tse) flies. In current review, retrospective studies of published literature on distribution and prevalence of Trypanosoma evansi infection in the Red Sea Countries was conducted [Google Scholar and PubMed were used to retrieve the published literature from 2000-2020. A total of 77 published articles met the eligibility criteria and were reviewed. A total of 16 reports have been reported on the prevalence and distribution of Trypnosoma evansi infection in the Red Sea Countries have been from 2010-2020]. According to the published literature, we can say that trypanosomiasis in camels are more prevalent in Sudan than in other countries, followed by 17% and 51.78% in both clinical and non-clinical cases. Hence, the reliable diagnostic tests should be used for rapid treatment or control of the disease as if not treated appropriately in early-stage, can lead to death of the camels.

A tripanossomíase é uma infecção por protozoário que afeta humanos e animais em quase todas as partes do mundo. Pode afetar grande variedade de hospedeiros domésticos e selvagens, incluindo camelídeos, equinos, gado, búfalos, ovelhas, cabras, porcos, cães e outros carnívoros, veados, gazelas e elefantes. Este artigo de revisão foi elaborado para abordar o efeito dessa doença economicamente importante em países do mar Vermelho, especialmente Egito, Sudão, Somália e Arábia Saudita, durante o período de 2010 a 2020. A prevalência de tripanossomíase é diferente entre esses países devido a tipos distintos de métodos diagnósticos (esfregaços de sangue corados com Giemsa, centrifugação de hematócrito, teste sorológico e PCR de análise molecular) usados e distribuição diferencial de moscas vetoras (tsé-tsé). Na revisão atual, foram realizados estudos retrospectivos da literatura publicada sobre distribuição e prevalência da infecção por Trypanosoma evansi nos países do mar Vermelho [Google Scholar e PubMed foram usados para recuperar a literatura publicada de 2000 a 2020. Um total de 77 artigos publicados preencheu os critérios de elegibilidade e foi revisado. E há também 16 relatos sobre a prevalência e distribuição da infecção por Trypnosoma evansi nos países do mar Vermelho, de 2010 a 2020]. De acordo com a literatura publicada, podemos afirmar que a tripanossomíase em camelos é mais prevalente no Sudão do que em outros países, seguida por 17% e 51,78% em casos clínicos e não clínicos. Assim, os testes diagnósticos confiáveis devem ser utilizados para o tratamento rápido ou controle da doença, pois, se eles não forem tratados de forma adequada na fase inicial, isso pode levar à morte dos camelos.

Proportion and seasonality of blood parasites in animals in Mosul using the Veterinary Teaching Hospital Lab data.

Several local studies have examined evidence of blood parasites in different animals in Mosul; however, information about the most prevalent parasite and the seasonality of the infection remains limited. The objective of the study conducted here was to investigate the proportion and seasonality of blood parasites in animals in Mosul using the Veterinary Teaching Hospital Lab data. Laboratory records for a period of 25 months were used for data retrieval. In all included animals, Giemsa-stained blood smears were examined by an attending clinical pathologist for the presence of parasites. Seasons were assigned on a basis of examination date, and the seasonality was quantified by estimating season-to-season ratio. The results indicated that 61.77% of examined animals were tested positive for blood parasites. The most evident parasites were Trypanosoma spp., Theileria spp., Babesia spp., and then Anaplasma spp., with evidence of mixed infection. The odds of the infection did not significantly vary in different age groups. There was a marked linear pattern in the seasonality of the infection with Trypanosoma spp. and Anaplasma spp. An increase of the infection during spring and autumn with Theileria spp. and Babesia spp. was also evident. In conclusion, infection with blood parasites in different animals in Mosul is common with substantial burden, the effect of age-related infection is negligible, and the seasonality of the infection is evident.

Pathogenic role of mitogen activated protein kinases in protozoan parasites.

Protozoan parasites with complex life cycles have high mortality rates affecting billions of human lives. Available anti-parasitic drugs are inadequate due to variable efficacy, toxicity, poor patient compliance and drug-resistance. Hence, there is an urgent need for the development of safer and better chemotherapeutics. Mitogen Activated Protein Kinases (MAPKs) have drawn much attention as potential drug targets. This review summarizes unique structural and functional features of MAP kinases and their possible role in pathogenesis of obligate intracellular protozoan parasites namely, Leishmania, Trypanosoma, Plasmodium and Toxoplasma. It also provides an overview of available knowledge concerning the target proteins of parasite MAPKs and the need to understand and unravel unknown interaction network(s) of MAPK(s).

Culicoides Latreille (Diptera: Ceratopogonidae) as potential vectors for Leishmania martiniquensis and Trypanosoma sp. in northern Thailand.

Biting midges of genus Culicoides (Diptera: Ceratopogonidae) are the vectors of several pathogenic arboviruses and parasites of humans and animals. Several reports have suggested that biting midges might be a potential vector of Leishmania parasites. In this study, we screened for Leishmania and Trypanosoma DNA in biting midges collected from near the home of a leishmaniasis patient in Lamphun province, northern Thailand by using UV-CDC light traps. The identification of biting midge species was based on morphological characters and confirmed using the Cytochrome C oxidase subunit I (COI) gene. The detection of Leishmania and Trypanosoma DNA was performed by amplifying the internal transcribed spacer 1 (ITS1) and small subunit ribosomal RNA (SSU rRNA) genes, respectively. All the amplified PCR amplicons were cloned and sequenced. The collected 223 biting midges belonged to seven species (Culicoides mahasarakhamense, C. guttifer, C. innoxius, C. sumatrae, C. huffi, C. oxystoma, and C. palpifer). The dominant species found in this study was C. mahasarakhamense (47.53%). Leishmania martiniquensis DNA was detected in three samples of 106 specimens of C. mahasarakhamense tested indicating a field infection rate of 2.83%, which is comparable to reported rates in local phlebotomines. Moreover, we also detected Trypanosoma sp. DNA in one sample of C. huffi. To our knowledge, this is the first molecular detection of L. martiniquensis in C. mahasarakhamense as well as the first detection of avian Trypanosoma in C. huffi. Blood meal analysis of engorged specimens of C. mahasarakhamense, C. guttifer, and C. huffi revealed that all specimens had fed on avian, however, further studies of the host ranges of Culicoides are needed to gain a better insight of potential vectors of emerging leishmaniasis. Clarification of the vectors of these parasites is also important to provide tools to establish effective disease prevention and control programs in Thailand.

Trypanosoma evansi evades host innate immunity by releasing extracellular vesicles to activate TLR2-AKT signaling pathway.

Surra, one of the most important animal diseases with economic consequences in Asia and South America, is caused by Trypanosoma evansi. However, the mechanism of immune evasion by T. evansi has not been extensively studied. In the present study, T. evansi extracellular vesicles (TeEVs) were characterized and the role of TeEVs in T. evansi infection were examined. The results showed that T. evansi and TeEVs could activate TLR2-AKT pathway to inhibit the secretions of IL-12p40, IL-6, and TNF-α in mouse BMDMs. TLR2-/- mice and mice with a blocked AKT pathway were more resistant to T. evansi infection than wild type (WT) mice, with a significantly lower infection rate, longer survival time and less parasite load, as well as an increased secretion level of IL-12p40 and IFN-γ. Kinetoplastid membrane protein-11 (KMP-11) of TeEVs could activate AKT pathway and inhibit the productions of IL-12p40, TNF-α, and IL-6 in vitro. TeEVs and KMP-11 could inhibit the productions of IL-12p40 and IFN-γ, promote T. evansi proliferation and shorten the survival time of infected mice in vivo. In conclusion, T. evansi could escape host immune response through inhibiting the productions of inflammatory cytokines via secreting TeEVs to activate TLR2-AKT pathway. KMP-11 in TeEVs was involved in promoting T. evansi infection.Extracellular vesicles (EVs) secreted by Trypanosoma evansi (T. evansi) activate the TLR2-AKT signaling pathway to inhibit the production of inflammatory cytokines, thereby escaping the host's immune response. Kinetoplastid membrane protein-11 (KMP-11) in EVs is related to the promotion of T.evansi infection via AKT pathway.

Functional traits linked to pathogen prevalence in wild bee communities.

Reports of pollinator declines have prompted efforts to understand contributing factors and protect vulnerable species. While pathogens can be widespread in bee communities, less is known about factors shaping pathogen prevalence among species. Functional traits are often used to predict susceptibility to stressors, including pathogens, in other species-rich communities. Here, we evaluated the relationship between bee functional traits (body size, phenology, nesting location, sociality, and foraging choice) and prevalence of trypanosomes, neogregarines, and the microsporidian Nosema ceranae in wild bee communities. For the most abundant bee species in our system, Bombus impatiens, we also evaluated the relationship between intra-specific size variation and pathogen prevalence. A trait-based model fit the neogregarine prevalence data better than a taxa-based model, while the taxonomic model provided a better model fit for N. ceranae prevalence, and there was no marked difference between the models for trypanosome prevalence. We found that Augochlorella aurata was more likely to harbor trypanosomes than many other bee taxa. Similarly, we found that bigger bees and those with peak activity later in the season were less likely to harbor trypanosomes, though the effect of size was largely driven by A. aurata. We found no clear intra-specific size patterns for pathogen prevalence in B. impatiens. These results indicate that functional traits are not always better than taxonomic affinity in predicting pathogen prevalence, but can help to explain prevalence depending on the pathogen in species-rich bee communities.

Computational Identification of Master Regulators Influencing Trypanotolerance in Cattle.

African Animal Trypanosomiasis (AAT) is transmitted by the tsetse fly which carries pathogenic trypanosomes in its saliva, thus causing debilitating infection to livestock health. As the disease advances, a multistage progression process is observed based on the progressive clinical signs displayed in the host's body. Investigation of genes expressed with regular monotonic patterns (known as Monotonically Expressed Genes (MEGs)) and of their master regulators can provide important clue for the understanding of the molecular mechanisms underlying the AAT disease. For this purpose, we analysed MEGs for three tissues (liver, spleen and lymph node) of two cattle breeds, namely trypanosusceptible Boran and trypanotolerant N'Dama. Our analysis revealed cattle breed-specific master regulators which are highly related to distinguish the genetic programs in both cattle breeds. Especially the master regulators MYC and DBP found in this study, seem to influence the immune responses strongly, thereby susceptibility and trypanotolerance of Boran and N'Dama respectively. Furthermore, our pathway analysis also bolsters the crucial roles of these master regulators. Taken together, our findings provide novel insights into breed-specific master regulators which orchestrate the regulatory cascades influencing the level of trypanotolerance in cattle breeds and thus could be promising drug targets for future therapeutic interventions.

Phylogenomics from transcriptomic "bycatch" clarify the origins and diversity of avian trypanosomes in North America.

The eukaryotic blood parasite genus Trypanosoma includes several important pathogens of humans and livestock, but has been understudied in wildlife broadly. The trypanosomes that infect birds are in particular need of increased attention, as these parasites are abundant and globally distributed, yet few studies have addressed their evolutionary origins and diversity using modern molecular and analytical approaches. Of specific interest are the deep evolutionary relationships of the avian trypanosomes relative to the trypanosome species that are pathogenic in humans, as well as their species level diversity in regions where they have been understudied such as North America. Here, we address these unresolved areas of study using phylogenomic data for two species of avian trypanosomes that were isolated as "bycatch" from host transcriptome assemblies, as well as a large 18S DNA barcode sequence dataset that includes 143 novel avian Trypanosoma 18S sequences from North America. Using a phylogenomic approach, we find that the avian trypanosomes are nested within a clade of primarily mammalian trypanosomes that includes the human pathogen Trypanosoma cruzi, and are paraphyletic with respect to the ruminant trypanosome Trypanosoma theileri. DNA barcode sequences showed that T. avium and an unidentified small, non-striated trypanosome that was morphologically similar to T. everetti are each represented by highly abundant and divergent 18S haplotypes in North America. Community-level sampling revealed that additional species-level Trypanosoma lineages exist in this region. We compared the newly sequenced DNA barcodes from North America to a global database, and found that avian Trypanosoma 18S haplotypes generally exhibited a marked lack of host specificity with at least one T. avium haplotype having an intercontinental distribution. This highly abundant T. avium haplotype appears to have a remarkably high dispersal ability and cosmopolitan capacity to evade avian host immune defenses, which warrant further study.

A new automated chilled adult release system for the aerial distribution of sterile male tsetse flies.

Tsetse eradication continues to be a top priority for African governments including that of Senegal, which embarked on a project to eliminate Glossina palpalis gambiensis from the Niayes area, following an area-wide integrated pest management approach with an SIT component. A successful SIT programme requires competitive sterile males of high biological quality. This may be hampered by handling processes including irradiation and the release mechanisms, necessitating continued improvement of these processes, to maintain the quality of flies. A new prototype of an automated chilled adult release system (Bruno Spreader Innovation, (BSI™)) for tsetse flies was tested for its accuracy (in counting) and release rate consistency. Also, its impact on the quality of the released sterile males was evaluated on performance indicators, including flight propensity, mating competitiveness, premating and mating duration, insemination rate of mated females and survival of male flies. The BSITM release system accurately counted and homogenously released flies at the lowest motor speed set (0.6 rpm), at a consistent rate of 60±9.58 males/min. Also, the release process, chilling (6 ± 1°C) and passing of flies through the machine) had no significant negative impact on the male flight propensity, mating competitiveness, premating and mating durations and the insemination rates. Only the survival of flies was negatively affected whether under feeding or starvation. The positive results of this study show that the BSI™ release system is promising for use in future tsetse SIT programmes. However, the negative impact of the release process on survival of flies needs to be addressed in future studies and results of this study confirmed under operational field conditions in West Africa.

Of Drugs and Trypanosomatids: New Tools and Knowledge to Reduce Bottlenecks in Drug Discovery.

Leishmaniasis (Leishmania species), sleeping sickness (Trypanosoma brucei), and Chagas disease (Trypanosoma cruzi) are devastating and globally spread diseases caused by trypanosomatid parasites. At present, drugs for treating trypanosomatid diseases are far from ideal due to host toxicity, elevated cost, limited access, and increasing rates of drug resistance. Technological advances in parasitology, chemistry, and genomics have unlocked new possibilities for novel drug concepts and compound screening technologies that were previously inaccessible. In this perspective, we discuss current models used in drug-discovery cascades targeting trypanosomatids (from in vitro to in vivo approaches), their use and limitations in a biological context, as well as different examples of recently discovered lead compounds.

Molecular changes in Trypanosoma evansi after treatment against trypanosomosis.

Neither physiological nor pathological changes following treatments explained why trypanosomes in the same group of experimentally treated animals correlated in virulence. Also, they behaved like each other but not similar to other groups despite the same T. evansi injected strain. The current study aims to discuss whether molecular changes might occur to Trypanosoma evansi isolates followed treatments are responsible for that difference or not. Ten preserved isolates from T. evansi after previous treatments besides the original strain of T. evansi that injected before treatments were used in the present study. These isolates were intraperitoneally inoculated in 11 groups of male Wister Albino rats with equal doses. Parasitological findings and the molecular changes accompanied were discussed along with the experiment based on PCR-TR3/TR4 specific-primers. The study also achieved alignments, gene sequence and phylogenetic analysis for submitted and reference strains belong to T. evansi, T. brucei, T. b. brucei, and T. b. gambiense deposited in GenBank. The present results assessed molecularly the effectiveness and highly antitrypanosomal activity of human plasmas O+ and A+ on T. evansi than others, and how their strains drifted from its original sequence to the nearest form of T. brucei. At the same time, T. evansi in other plant extract groups multiplied progressively like cancer cells and became more virulent and close to reference strains of T. evansi. Our data further indicated that T. evansi after treatment was a paraphyletic group. It also corroborated the antitrypanosomal activityspecificity and the molecular changes occurring were correlated to the type of treatment.

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis.

Unicellular eukaryotes of the Trypanosomatidae family include human and animal pathogens that belong to the Trypanosoma and Leishmania genera. Diagnosis of the diseases they cause requires the sampling of body fluids (e.g., blood, lymph, peritoneal fluid, cerebrospinal fluid) or organ biopsies (e.g., bone marrow, spleen), which are mostly obtained through invasive methods. Body fluids or appendages can be alternatives to these invasive biopsies but appropriateness remains poorly studied. To further address this question, we perform a systematic review on clues evidencing the presence of parasites, genetic material, antibodies, and antigens in body secretions, appendages, or the organs or proximal tissues that produce these materials. Paper selection was based on searches in PubMed, Web of Science, WorldWideScience, SciELO, Embase, and Google. The information of each selected article (n = 333) was classified into different sections and data were extracted from 77 papers. The presence of Trypanosomatidae parasites has been tracked in most of organs or proximal tissues that produce body secretions or appendages, in naturally or experimentally infected hosts. The meta-analysis highlights the paucity of studies on human African trypanosomiasis and an absence on animal trypanosomiasis. Among the collected data high heterogeneity in terms of the I2 statistic (100%) is recorded. A high positivity is recorded for antibody and genetic material detection in urine of patients and dogs suffering leishmaniasis, and of antigens for leishmaniasis and Chagas disease. Data on conjunctival swabs can be analyzed with molecular methods solely for dogs suffering canine visceral leishmaniasis. Saliva and hair/bristles showed a pretty good positivity that support their potential to be used for leishmaniasis diagnosis. In conclusion, our study pinpoints significant gaps that need to be filled in order to properly address the interest of body secretion and hair or bristles for the diagnosis of infections caused by Leishmania and by other Trypanosomatidae parasites.

SNP Diversity in CD14 Gene Promoter Suggests Adaptation Footprints in Trypanosome Tolerant N'Dama (Bos taurus) but not in Susceptible White Fulani (Bos indicus) Cattle.

Immune response to infections has been shown to be mediated by genetic diversity in pattern recognition receptors, leading to disease tolerance or susceptibility. We elucidated naturally occurring variations within the bovine CD14 gene promoter in trypanosome-tolerant (N'Dama) and susceptible (White Fulani) cattle, with genomic and computational approaches. Blood samples were collected from White Fulani and N'Dama cattle, genomic DNA extracted and the entire promoter region of the CD14 gene amplified by PCR. We sequenced this region and performed in silico computation to identify SNP variants, transcription factor binding sites, as well as micro RNAs in the region. CD14 promoter sequences were compared with the reference bovine genome from the Ensembl database to identify various SNPs. Furthermore, we validated three selected N'Dama specific SNPs using custom Taqman SNP genotyping assay for genetic diversity. In all, we identified a total of 54 and 41 SNPs at the CD14 promoter for N'Dama and White Fulani respectively, including 13 unique SNPs present in N'Dama only. The significantly higher SNP density at the CD14 gene promoter region in N'Dama may be responsible for disease tolerance, possibly an evolutionary adaptation. Our genotype analysis of the three loci selected for validation show that mutant alleles (A/A, C/C, and A/A) were adaptation profiles within disease tolerant N'Dama. A similar observation was made for our haplotype analysis revealing that haplotypes H1 (ACA) and H2 (ACG) were significant combinations within the population. The SNP effect prediction revealed 101 and 89 new transcription factor binding sites in N'Dama and White Fulani, respectively. We conclude that disease tolerant N'Dama possessing higher SNP density at the CD14 gene promoter and the preponderance of mutant alleles potentially confirms the significance of this promoter in immune response, which is lacking in susceptible White Fulani. We, therefore, recommend further in vitro and in vivo study of this observation in infected animals, as the next step for understanding genetic diversity relating to varying disease phenotypes in both breeds.

Expanding our knowledge on African trypanosomes of the subgenus Pycnomonas: A novel Trypanosoma suis-like in tsetse flies, livestock and wild ruminants sympatric with Trypanosoma suis in Mozambique.

Among the subgenera of African tsetse-transmitted trypanosomes pathogenic to livestock, the least known is the subgenus Pycnomonas, which contains a single species, Trypanosoma suis (TSU), a pathogen of domestic pigs first reported in 1905 and recently rediscovered in Tanzania and Mozambique. Analysis by Fluorescent Fragment Length Barcoding (FFLB) revealed an infection rate of 20.3% (108 out of 530 tsetse flies) in a recent study in the Gorongosa and Niassa wildlife reserves in Mozambique, and demonstrated two groups of Pycnomonas trypanosomes: one (14.1%, 75 flies) showing an FFLB profile identical to the reference TSU from Tanzania, and the other (6.2%, 33 flies) differing slightly from reference TSU and designated Trypanosoma suis-like (TSU-L). Phylogenetic analyses tightly clustered TSU and TSU-L from Mozambique with TSU from Tanzania forming the clade Pycnomonas positioned between the subgenera Trypanozoon and Nannomonas. Our preliminarily exploration of host ranges of Pycnomonas trypanosomes revealed TSU exclusively in warthogs while TSU-L was identified, for the first time for a member of the subgenus Pycnomonas, in ruminants (antelopes, Cape buffalo, and in domestic cattle and goats). The preferential blood meal sources of tsetse flies harbouring TSU and TSU-L were wild suids, and most of these flies concomitantly harboured the porcine trypanosomes T. simiae, T. simiae Tsavo, and T. godfreyi. Therefore, our findings support the link of TSU with suids while TSU-L remains to be comprehensively investigated in these hosts. Our results greatly expand our knowledge of the diversity, hosts, vectors, and epidemiology of Pycnomonas trypanosomes. Due to shortcomings of available molecular diagnostic methods, a relevant cohort of trypanosomes transmitted by tsetse flies to ungulates, especially suids, has been neglected or most likely misidentified. The method employed in the present study enables an accurate discrimination of trypanosome species and genotypes and, hence, a re-evaluation of the "lost" subgenus Pycnomonas and of porcine trypanosomes in general, the most neglected group of African trypanosomes pathogenic to ungulates.

The Indirect ELISA Trypanosoma evansi in Equids: Optimisation and Application to a Serological Survey including Racing Horses, in Thailand.

Surra, caused by Trypanosoma evansi, is a widely distributed animal trypanosomosis; it affects both domestic and wild mammals with high economic impact. Clinical picture is moderate in bovines but severe in equids. Surra is also an important constraint for international animal trade and movements. Despite its impact, surra remains poorly diagnosed because of low sensitivity tests. To improve epidemiological knowledge of the disease and to secure international movement, efficient diagnosis tools are required. Here, we optimized and applied to equids the OIE-recommended indirect ELISA T. evansi that was validated in other species. Based on 96 positive and 1,382 negative horse reference samples from Thailand, a TG-ROC analysis was conducted to define the cutoff value. ELISA's sensitivity and specificity were estimated at 97.5% and 100%, respectively, qualifying the test to provide a reliable immune status of equids. The test was then applied on 1,961 horse samples from 18 Thai Provinces; the only scarce positives suggested that horses do not constitute a reservoir of T. evansi in Thailand. All samples from racing horses were negative. Conversely, two outbreaks of surra reported to our laboratory, originating from a bovine reservoir, exhibited high morbidity and lethality rates in horses. Finally, posttreatment follow-ups of infected animals allowed us to provide outbreak management guidelines.

Application of Dithiocarbamates as Potential New Antitrypanosomatids-Drugs: Approach Chemistry, Functional and Biological.

Dithiocarbamates represent a class of compounds that were evaluated in different biomedical applications because of their chemical versatility. For this reason, several pharmacological activities have already been attributed to these compounds, such as antiparasitic, antiviral, antifungal activities, among others. Therefore, compounds that are based on dithiocarbamates have been evaluated in different in vivo and in vitro models as potential new antimicrobials. Thus, the purpose of this review is to present the possibilities of using dithiocarbamate compounds as potential new antitrypanosomatids-drugs, which could be used for the pharmacological control of Chagas disease, leishmaniasis, and African trypanosomiasis.

Detection of Extravascular Trypanosoma Parasites by Fine Needle Aspiration.

Fine Needle Aspiration (FNA) is a routine diagnostic procedure essential to both medical and veterinary practices. It consists of the percutaneous aspiration of cells and/or microorganisms from palpable masses, organs or effusions (fluid accumulation in a body cavity) using a thin needle similar to the regular needle used for the venous puncture. The material collected by FNA is in general highly cellular, and the retrieved aspirate is then smeared, air dried, wet-fixed, stained and observed under a microscope. In the clinical context, FNA is an important diagnostic tool that serves as a guide to the appropriate therapeutic management. Because it is simple, fast, minimally invasive and requires limited investment in the laboratory and human resources, it is extensively used by veterinary practitioners, mostly in domestic, but also in farm animals. In studies using animal models, FNA has the advantage that it can be performed repeatedly in the same animal, enabling longitudinal studies through the collection of cells from tumors and organs/tissues over the course of the disease. In addition to routine microscopy, retrieved material can also be used for immunocytochemistry, electron microscopy, biochemical analysis, flow cytometry, molecular biology or in vitro assays. FNA has been used to identify the protozoan parasite Trypanosoma brucei in the gonads of infected mice, opening the possibility for a future diagnosis in cattle.

Intracellular protozoan parasites: living probes of the host cell surface molecular repertoire.

Intracellular protozoans co-evolved with their mammalian host cells a range of strategies to cope with the composite and dynamic cell surface features they encounter during migration and infection. Therefore, these single-celled eukaryotic parasites represent a fascinating source of living probes for precisely capturing the dynamic coupling between the membrane and contractile cortex components of the cell surface. Such biomechanical changes drive a constant re-sculpting of the host cell surface, enabling rapid adjustments that contribute to cellular homeostasis. As emphasized in this review, through the design of specific molecular devices and stratagems to interfere with the biomechanics of the mammalian cell surface these parasitic microbes escape from dangerous or unfavourable microenvironments by breaching host cell membranes, directing the membrane repair machinery to wounded membrane areas, or minimizing membrane assault using discretion and speed when invading host cells for sustained residence.

Equine trypanosomosis: enigmas and diagnostic challenges.

Equine trypanosomosis is a complex of infectious diseases called dourine, nagana and surra. It is caused by several species of the genus Trypanosoma that are transmitted cyclically by tsetse flies, mechanically by other haematophagous flies, or sexually. Trypanosoma congolense (subgenus Nannomonas) and T. vivax (subgenus Dutonella) are genetically and morphologically distinct from T. brucei, T. equiperdum and T. evansi (subgenus Trypanozoon). It remains controversial whether the three latter taxa should be considered distinct species. Recent outbreaks of surra and dourine in Europe illustrate the risk and consequences of importation of equine trypanosomosis with infected animals into non-endemic countries. Knowledge on the epidemiological situation is fragmentary since many endemic countries do not report the diseases to the World Organisation for Animal Health, OIE. Other major obstacles to the control of equine trypanosomosis are the lack of vaccines, the inability of drugs to cure the neurological stage of the disease, the inconsistent case definition and the limitations of current diagnostics. Especially in view of the ever-increasing movement of horses around the globe, there is not only the obvious need for reliable curative and prophylactic drugs but also for accurate diagnostic tests and algorithms. Unfortunately, clinical signs are not pathognomonic, parasitological tests are not sufficiently sensitive, serological tests miss sensitivity or specificity, and molecular tests cannot distinguish the taxa within the Trypanozoon subgenus. To address the limitations of the current diagnostics for equine trypanosomosis, we recommend studies into improved molecular and serological tests with the highest possible sensitivity and specificity. We realise that this is an ambitious goal, but it is dictated by needs at the point of care. However, depending on available treatment options, it may not always be necessary to identify which trypanosome taxon is responsible for a given infection.

Intravital imaging of host-parasite interactions in skin and adipose tissues.

Intravital microscopy allows the visualisation of how pathogens interact with host cells and tissues in living animals in real time. This method has enabled key advances in our understanding of host-parasite interactions under physiological conditions. A combination of genetics, microscopy techniques, and image analysis have recently facilitated the understanding of biological phenomena in living animals at cellular and subcellular resolution. In this review, we summarise findings achieved by intravital microscopy of the skin and adipose tissues upon infection with various parasites, and we present a view into possible future applications of this method.