The prevalence rates of trypanosomes, including those that require cyclical transmission by tsetse flies, are widely distributed in Africa. Trypanosoma brucei and Trypanosoma congolense are actively maintained in regions where there are no tsetse flies although at low frequencies. Whether this could be due to an independent evolutionary origin or multiple introduction of trypanosomes due to continuous movement of livestock between tsetse-free and -infested areas is not known. Thus, the aim of the study was to carry out microsatellite genotyping to explore intra-specific genetic diversity between T. (Trypanozoon), T. congolense and Trypanosoma vivax from the two regions: tsetse infested and tsetse free. Microsatellite genotyping showed geographical origin-based structuring among T. (Trypanozoon) isolates. There was a clear separation between isolates from the two regions signalling the potential of microsatellite markers as diagnostic markers for T. brucei and Trypanosoma evansi isolates. Trypanosoma vivax isolates also clustered largely based on the sampling location with a significant differentiation between the two locations. However, our results revealed that T. congolense isolates from Northern Kenya are not genetically separated from those from Coastal Kenya. Therefore, these isolates are likely introduced in the region through animal movement. Our results demonstrate the occurrence of both genetic connectivity as well as independent evolutionary origin, depending on the trypanosome species between the two ecologies.

Pathogens and lack of floral resources interactively impair global pollinator health. However, epidemiological and nutritional studies aimed at understanding bee declines have historically focused on social species, with limited evaluations of solitary bees. Here, we asked whether Crithidia bombi, a trypanosomatid gut pathogen known to infect bumble bees, could infect the solitary bees Osmia lignaria (females) and Megachile rotundata (males), and whether nutritional stress influenced infection patterns and bee survival. We found that C. bombi was able to infect both solitary bee species, with 59% of O. lignaria and 29% of M. rotundata bees experiencing pathogen replication 5–11 days following inoculation. Moreover, access to pollen resulted in O. lignaria living longer, although it did not influence M. rotundata survival. Access to pollen did not affect infection probability or resulting pathogen load in either species. Similarly, inoculating with the pathogen did not drive survival patterns in either species during the 5–11-day laboratory assays. Our results demonstrate that solitary bees can be hosts of a known bumble bee pathogen, and that access to pollen is an important contributing factor for bee survival, thus expanding our understanding of factors contributing to solitary bee health.

Trypanocide resistance remains a huge challenge in the management of animal African trypanosomiasis. Paucity of data on the prevalence of multi-drug resistant trypanosomes has greatly hindered optimal veterinary management practices. We use mathematical model predictions to highlight appropriate drug regimens that impede trypanocide resistance development in cattle. We demonstrate that using drugs in decreasing resistance order results in a negligible increase in number of cattle with resistant infection, in contrast to a more pronounced increase from trypanocide use in increasing resistance order. We demonstrate that the lowest levels of trypanocide resistance are achieved with combination therapy. We also show that increasing the number of cattle treated leads to a progressive reduction in the number of cattle with drug resistant infections for treatments of up to 80% of the cattle population for the combination treatment strategy. Our findings provide an initial evidence-based framework on some essential practices that promote optimal use of the handful of trypanocides. We anticipate that our modest forecasts will improve therapeutic outcomes by appropriately informing on the best choice, and combination of drugs that minimize treatment failure rates.

The prevalence and community composition of haemoparasites can substantially differ among avian host populations, which may lead to different selection pressures. Therefore, information about these parameters is crucial for understanding, e.g. the inter-population variation in host life history traits. Here, we molecularly screened a population of a long-distance migrant, the pied flycatcher Ficedula hypoleuca, from central Poland for the presence of three genera of blood parasites: Haemoproteus, Plasmodium and Trypanosoma. The infection rate in this population was the highest for haemosporidians (86·8%) and one of the highest for trypanosomes (39·7%) among the thus far screened breeding populations of this species. The haemosporidian community was composed of six Haemoproteus/Plasmodium lineages, and the trypanosome community – 4 species and a parasite assigned to genus level. Trypanosomes were dominated by T. culicavium, a recently described species, corroborating the prediction that insectivorous songbirds are vertebrate hosts of this parasite. Host sex and age did not explain variation in infection incidence except for the higher trypanosome infection rates in males. A comparison of the study population with three other breeding populations previously screened molecularly for haemosporidians showed some geographic differences. This study confirms the importance of examining local parasite communities across a host distribution range.

This study aimed to evaluate in vitro and in vivo trypanocidal activity of free and nanoencapsulated curcumin against Trypanosoma evansi. In vitro efficacy of free curcumin (CURC) and curcumin-loaded in lipid-core nanocapsules (C-LNCs) was evaluated to verify their lethal effect on T. evansi. To perform the in vivo tests, T. evansi-infected animals were treated with CURC (10 and 100 mg kg−1, intraperitoneally [i.p.]) and C-LNCs (10 mg kg−1, i.p.) during 6 days, with the results showing that these treatments significantly attenuated the parasitaemia. Infected untreated rats showed protein peroxidation and an increase of nitrites/nitrates, whereas animals treated with curcumin showed a reduction on these variables. As a result, the activity of antioxidant enzymes (superoxide dismutase and catalase) differs between groups (P<0·05). Infected animals and treated with CURC exhibited a reduction in the levels of alanine aminotransferase and creatinine, when compared with the positive control group. The use of curcumin in vitro resulted in a better parasitaemia control, an antioxidant activity and a protective effect on liver and kidney functions of T. evansi-infected adult male Wistar rats.

This study investigated the molecular prevalence of Trypanosoma lewisi and T. evansi in wild rodents from Cambodia, Lao PDR and Thailand. Between 2008 and 2012, rodents (and shrews) were trapped in nine locations and 616 of these were tested using three sets of primers: TRYP1 (amplifying ITS1 of ribosomal DNA of all trypanosomes), TBR (amplifying satellite genomic DNA of Trypanozoon parasites) and LEW1 (amplifying ITS1 of ribosomal DNA of T. lewisi). Based on the size of the PCR products using TRYP1, 17% were positive for T. lewisi and 1·0% positive for Trypanozoon. Results were confirmed by sequencing PCR products and by using more specific primers (LEW1 and TBR). The specificity of TRYP1 primers, however, failed as rodent DNA was amplified in some instances, giving unexpected product sizes. Using LEW1 primers, 13·3% of the samples were confirmed positive for T. lewisi, both by PCR and sequencing. In Thailand, T. lewisi was found in Rattus tanezumi, R. exulans and Berylmys; in Lao PDR, in R. tanezumi and R. exulans, and in Cambodia in R. tanezumi, R. exulans and R. norvegicus. Using TBR, 1·3% of the samples tested positive for Trypanozoon by PCR and sequencing; T. evansi is the only species of the Trypanozoon subgenus possibly present in wild Asian rodents. These results confirmed its presence in rodents from Thailand (R. tanezumi), Lao PDR (R. tanezumi, R. nitidus) and Cambodia (R. tanezumi, Niviventer fulvescens, Maxomys surifer). Based on the information related to rodent trapping, it was found that rodent species trapped in and around human dwellings had a higher prevalence of T. lewisi infection. R. tanezumi and R. exulans, two synanthropic species, were mainly found infected in this habitat suggesting a role as a reservoir and thus a potential source of T. lewisi for human infection.

The aim of this study was to investigate neurochemical and enzymatic changes in rats infected with Trypanosoma evansi, and their interference in the cognitive parameters. Behavioural assessment (assessment of cognitive performance), evaluation of cerebral L-[3H]glutamate uptake, acetylcholinesterase (AChE) activity and Ca+2 and Na+, K+-ATPase activity were evaluated at 5 and 30 days post infection (dpi). This study demonstrates a cognitive impairment in rats infected with T. evansi. At 5 dpi memory deficit was demonstrated by an inhibitory avoidance test. With the chronicity of the disease (30 dpi) animals showed anxiety symptoms. It is possible the inhibition of cerebral Na+, K+-ATPase activity, AChE and synaptosomal glutamate uptake are involved in cognitive impairment in infected rats by T. evansi. The understanding of cerebral host–parasite relationship may shed some light on the cryptic symptoms of animals and possibly human infection where patients often present with other central nervous system (CNS) disorders.

Glycosomes are specialized peroxisomes found in all kinetoplastid organisms. The organelles are unique in harbouring most enzymes of the glycolytic pathway. Matrix proteins, synthesized in the cytosol, cofactors and metabolites have to be transported across the membrane. Recent research on Trypanosoma brucei has provided insight into how these translocations across the membrane occur, although many details remain to be elucidated. Proteins are imported by a cascade of reactions performed by specialized proteins, called peroxins, in which a cytosolic receptor with bound matrix protein inserts itself in the membrane to deliver its cargo into the organelle and is subsequently retrieved from the glycosome to perform further rounds of import. Bulky solutes, such as cofactors and acyl-CoAs, seem to be translocated by specific transporter molecules, whereas smaller solutes such as glycolytic intermediates probably cross the membrane through pore-forming channels. The presence of such channels is in apparent contradiction with previous results that suggested a low permeability of the glycosomal membrane. We propose 3 possible, not mutually exclusive, solutions for this paradox. Glycosomal glycolytic enzymes have been validated as drug targets against trypanosomatid-borne diseases. We discuss the possible implications of the new data for the design of drugs to be delivered into glycosomes.

A total of 41 ticks were collected from 15 quokkas on Bald Island and 2 ticks from a Gilbert's potoroo from Two Peoples Bay. Three species of Ixodid ticks Ixodes australiensis, Ixodes hirsti and Ixodes myrmecobii were identified on the quokkas known to have a high prevalence of Trypanosoma copemani. Tick faeces from ticks isolated from 8 individual quokkas and a Gilbert's potoroo were examined with one identified as positive for trypanosomes. Faecal examination revealed trypanosomes similar to in vitro life-cycle stages of T. copemani. In total 12 ticks were dissected and trypanosomes found in sections of their midgut and haemolymph, 49 and 117 days after collection. Tick faeces, salivary glands and midguts from I. australiensis were screened using an 18S rRNA PCR with amplification seen only from the midguts. Sequencing showed 100% homology to T. copemani (genotype A) and 99·9% homology to the wombat (AII) isolate of T. copemani. Trypanosomes were only detected in I. australiensis as neither I. hirsti nor I. myrmecobii survived the initial 30-day storage conditions. We therefore identify a vector for T. copemani as I. australiensis and, given the detection of trypanosomes in the faeces, suggest that transmission is via the faecal-oral route.

The strengths and limitations of existing mass spectrometry methods for metabolite detection and identification are discussed. A brief review is made of the methods available for quenching and extraction of cells or organisms prior to instrumental analysis. The techniques available for carrying out mass spectrometry-based profiling of metabolomes are discussed using the analysis of extracts from trypanosomes to illustrate various points regarding methods of separation and mass spectrometric analysis. The advantages of hydrophilic interaction chromatography (HILIC) for the analysis of polar metabolites are discussed. The challenges of data processing are outlined and illustrated using the example of ThermoFisher's Sieve software. The existing literature on applications of mass spectrometry to the profiling of parasite metabolomes is reviewed.

Haemoflagellates of the genus Trypanosoma are prevalent in freshwater fishes and are transmitted by leeches as vectors. As demonstrated by sequence comparisons of nuclear small subunit rRNA genes, trypanosomes isolated from several fish species at different localities can be divided into at least 2 closely related types, designated Type A and Type B. A clone derived from a Type A isolate from carp (Cyprinus carpio) was used to study the anti-parasite immune response in specified pathogen-free outbred carp. Infection leads to an initial rise in parasitaemia in the blood followed by a sharp decline in all fish (acute phase). Thereafter, in some carp, parasites become undetectable both in the blood and in internal organs while, in others, low numbers can be found in the blood for up to 1 year (chronic phase). Fish that have controlled an acute infection with the clone are not only protected against an homologous challenge infection, but also against the infection with parasite lines derived from carp in the chronic phase of infection. Passive immunization experiments with IgM purified from serum of recovered carp indicate that the infection is controlled by antibodies. The anti-parasite antibody level in recovered carp remains high for many months although the parasitaemia is controlled at very low levels and the half life of IgM, t1/2=22·5 days, is comparatively short. The effective control of trypanosomes in laboratory infections is in contrast to the high prevalence in natural and farmed freshwater fish populations.

The prevalence of various species and subgroups of trypanosomes in the Sinfra area of C⊚te d'Ivoire was determined using the polymerase chain reaction (PCR). Using this technique to amplify specific satellite DNA targets, it was possible to identify developmental-stage trypanosomes in the midguts and the proboscides of tsetse without expansion of parasite populations. The predominant tsetse species in the area was Glossina palpalis, while G. pallicera and G. nigrofusca were also present. Microscopical examination of 811 non-teneral flies revealed an infection rate of 14% in midguts and/or proboscides. Three subgroups of Trypanosoma congolense (Savannah, Forest & Kilifi), T. simiae, T.godfreyi, West African T. vivax and T. brucei ssp. were identified using PCR. T. congolense Forest was the most abundant of the Nannomonas trypanosomes. Approximately 40% of all infections were mixed, and there was a significantly higher prevalence of apparently mature T. brucei ssp. trypanosomes than has previously been reported. The present study demonstrates that PCR facilitates the easy identification of mature trypanosome infections in tsetse, providing a reliable estimation of trypanosomiasis challenge.

Relatively simple protocols employing non-radioactive DNA probes have been used for the detection of African trypanosomes in the blood of mammalian hosts and the saliva of live tsetse flies. In combination with the polymerase chain reaction (PCR), the protocols revealed trypanosomes in buffy-coat samples from antigenaemic but aparasitaemic cattle and in the saliva of live, infected tsetse flies. Furthermore, the protocols were used to demonstrate concurrent natural infections of single tsetse flies with different species of African trypanosomes.

The presence of haemoparasites belonging to the taxa Anaplasma, Bartonella and Trypanosoma was determined among 76 common shrews (Sorex araneus) from Northwest England. Anaplasma phagocytophilum DNA was recovered from the blood of 1 shrew (1·3%), with the amplified 16S rRNA sequence identical to one previously reported from a bank vole (Clethrionomys glareolus). Trypanosoma spp. DNA was detected in 9 shrews (11·8%), the amplified 18S rDNA fragments being indistinguishable from one another, and distinct from previously published data. This represents the first report of trypanosome infection in S. araneus and suggests they are susceptible to an uncharacterized Trypanosoma species. Blood from 11 shrews (14·5%) yielded Bartonella spp., with characterization of isolates using comparative sequence analysis of partial gltA and 16S-23S rRNA intergenic spacer regions revealing 2 different genotypes. Phylogenetic inference from alignment of partial gltA sequences found that both UK S. araneus types formed a well-supported cluster with Bartonella sp. isolated from S. araneus in Sweden. No significant effect of host age, sex, or year of collection was found on prevalence of Bartonella or trypanosome infections. The results of this survey demonstrate that common shrews in the UK are susceptible to haemoparasitic infections, at prevalences similar to those reported from sympatric rodents.

We are studying early events in the establishment of Trypanosoma brucei in the tsetse midgut using fluorescent trypanosomes to increase visibility. Feeding flies with the lectin-inhibitory sugars D-glucosamine (GlcN) or N-acetyl-glucosamine (GlcNAc) has previously been shown to enhance fly susceptibility to infection with trypanosomes and, as expected, we found that both sugars increased midgut infection rates of Glossina morsitans morsitans with T. brucei. However, GlcNAc did not show the inhibitory effect on salivary gland infection rate reported previously for GlcN. Both sugars significantly slowed the movement of the bloodmeal along the midgut. GlcN also significantly increased the size of the bloodmeal taken and fly mortality. The most surprising finding was that GlcNAc stimulated trypanosome growth not only in the midgut, but also in vitro in the absence of any factor derived from the fly. Thus our direct comparison of the effects of GlcN and GlcNAc on the trypanosome-tsetse interaction has shown that these sugars impact on trypanosome growth and tsetse physiology in different ways and are not interchangeable as suggested in the literature. The sugars cause multiple effects, not restricted solely to the inhibition of midgut lectins. These findings have implications for current models of tsetse susceptibility to trypanosome infection.

Host nutrition plays an important role in determining the development and success of parasitic infections. While studies of vertebrate hosts are accumulating, little is known about how host nutrition affects parasites of invertebrate hosts. Crithidia bombi is a gut trypanosome parasite of the bumble bee, Bombus terrestris and here we use it as a model system to determine the impact of host nutrition on the population dynamics and development of micro-parasites in invertebrates. Pollen-starved bees supported significantly smaller populations of the parasite. In pollen-fed bees the parasite showed a temporal pattern in development, with promastigote transmission stages appearing at the start of the infection and gradually being replaced by choanomastigote and amastigote forms. In pollen-starved bees this developmental process was disrupted, and there was no pattern in the appearance of these three forms. We discuss the implications of these results for parasite transmission, and speculate about the mechanisms behind these changes.

A study was carried out for four years in the forest area of Daloa in Côte d'Ivoire to assess the rate of trypanosome infection in tsetse, and thereby the trypanosomiasis infection risk. In different Glossina biotopes, 18,908 Glossina palpalis palpalis were caught with Vavoua traps and were dissected. The most widespread species of trypanosomes infecting the Glossina was Trypanosoma congolense (7.63%) followed by T. vivax (4.50%). Trypanosoma brucei, the trypanosome responsible for animal and human African trypanosomiasis (HAT), was found only in 34 of the tsetse flies collected, and it had a very low infection rate (0.18%). Although infected tsetse flies were captured in all habitats examined, the infection rate was relatively higher along footpaths (0.44%), in farms (0.20%) and around forested water springs (0.27%) compared to the edge of villages (0.06%) and forest borders (0.05%). Among the 34 tsetse flies infected with T. brucei, only 0.05% had parasites exclusively in their salivary glands. Our results suggest that footpaths, plantations of coffee and cocoa and forested water springs are potential biotopes where the risk of infection by T. brucei is most important. The anthropophily of Glossina associated with the high number of parasites in these sites could be the reason for the disease is endemic in Daloa today. In our study, female Glossina were infected more frequently with trypanosomes (0.14%) than males (0.04%) and generally, females lived longer than males. It is likely that the longevity of females, which carry parasites, is the major cause for the endemicity of HAT in this locality.

Many parasites, including important species that affect humans and livestock, must survive the harsh environment of insect guts to complete their life-cycle. Hence, understanding how insects protect themselves against such parasites has immediate practical implications. Previously, such protection has been thought to consist mainly of mechanical structures and the action of lectins. However, recently it has become apparent that gut infections may interact with the host immune system in more complex ways. Here, using bumble bees, Bombus terrestris and their non-invasive gut trypanosome, Crithidia bombi, as a model system we investigated the effects of parasitic infection, host resources and the duration of infections on the host immune system. We found that infection doubled standing levels of immune defence in the haemolymph (the constitutive pro-phenoloxidase system), which is used as a first, general defence against parasites. However, physical separation of the parasite from the haemolymph suggests the presence of a messenger system between the gut and the genes that control the pro-phenoloxidase system. Surprisingly, we found no direct effect of host resource-stress or duration of the infection on the immune system. Our results suggest a novel and tactical response of insects to gut infections, demonstrating the complexity of such host–parasite systems.

Trypanosome infections are often difficult to detect by conventional microscopy and their pleomorphy often confounds differential diagnosis. Molecular techniques are now being used to diagnose infections and to determine phylogenetic relationships between species. Complete small subunit rRNA gene sequences were determined for isolates of Trypanosoma chelodina from the Brisbane River tortoise (Emydura signata), the saw-shelled tortoise (Elseya latisternum), and the eastern snake-necked tortoise (Chelodina longicollis) from southeast Queensland, Australia. Partial sequence data were also obtained for T. binneyi from a platypus (Ornithorhynchus anatinus) from Tasmania. Phylogenetic relationships between T. chelodina, T. binneyi and other species were examined by maximum parsimony and likelihood methods. The Australian tortoise and platypus trypanosomes did not exhibit any close phylogenetic relationships with those of mammals, reptiles or amphibians, but were closely related to each other, and to fish trypanosomes. This contra-indicates their co-evolution with their vertebrate hosts but does not exclude co-evolution with different groups of invertebrate vectors, notably insects and leeches.