Development of a microsphere-based immunoassay for the serological diagnosis of equine trypanosomosis.

Trypanozoon infections in equids are caused by three parasite species in the Trypanozoon subgenus: Trypanosoma equiperdum, T. brucei and T. evansi. They are respectively responsible for infectious diseases dourine, nagana and surra. Due to the threat that Trypanozoon infection represents for international horse trading, accurate diagnostic tests are crucial. Current tests suffer from poor sensitivity and specificity, due in the first case to the transient presence of parasites in the blood and in the second, to antigenic cross-reactivity among Trypanozoon subspecies. This study was designed to develop a microsphere-based immunoassay for diagnosing equine trypanosomosis. We tested beads coated with eight Trypanosoma spp. recombinant antigens: enolase, GM6, PFR1, PFR2, ISG65, VSGat, RoTat1.2 and JN2118HU. Of these, GM6 was identified as the best candidate for the serological diagnosis of Trypanozoon infections in equids. Using a receiver operating characteristic (ROC) analysis on 349 equine sera, anti-GM6 antibodies were detected with an AUC value of 0.994 offering a sensitivity of 97.9% and a specificity of 96.0%. Our findings show that the GM6 antigen is a good target for diagnosing equine trypanosomosis using a microsphere-based immunoassay. This promising assay could be a useful alternative to the official diagnostic tool for equine trypanosomosis.

Serum proteomic signature of Trypanosoma evansi -infected mice for identification of potential biomarkers.

Trypanosoma evansi is the agent of "surra," a trypanosomosis endemic in many areas worldwide. Trypanosoma proteins released/secreted during infection are attractive biomarkers for disease detection and monitoring. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we performed a comprehensive analysis of the serum proteome of mice infected with T.evansi and detected changes in the abundance of parasite and host serum proteins during infection. Following bioinformatics analysis, 30 T. evansi proteins were identified in the mice serum including known targets such as pyruvate kinase 1, ß-tubulin, actin A, heat shock protein 70, and cyclophilin A. We also identified two exclusive VSG epitopes which are novel putative biomarker targets. In addition, upregulation of 31 mouse proteins, including chitinase-like protein 3 and monocyte differentiation antigen CD14, were observed. Identification of parasite-specific biomarkers in the host serum is critical for the development of reliable serological/ assays for differential diagnosis.

Molecular surveillance reveals bats from eastern Colombia infected with Trypanosoma theileri and Trypanosoma wauwau-like parasites.

Several species of trypanosomes can infect bats (Chiroptera), but current information about bat trypanosomes in Colombia is scarce. The objectives of this study were to estimate the infection rate and to characterize the trypanosome species infecting bats from three rural regions near the municipality of Cumaribo in Vichada, Colombia. Blood samples were collected from 39 bats. DNA was extracted from the blood samples and analyzed using nuclear genetic markers (SSU rDNA, ITS rDNA, and cathepsin genes) to discriminate among trypanosome species. Trypanosomes were detected in 66.7 % (26/39) of blood samples using PCR; 61.5 % (24/39) of infections were identified as Trypanosoma theileri and 5.1 % (2/39) as T. wauwau-like parasites. The phylogeographic analysis revealed that our T. theileri sequences were associated with the TthIIB genotype from cattle in Brazil and Venezuela. The T. wauwau-like parasites represent a new genotype of the species and were found in Molossus molossus and Platyrrhinus helleri bats. These data represent the first evidence of this trypanosome in both Colombia, and in these species of bats. Bat infections with T. theileri suggest an important role of these hosts in maintaining this genotype, probably acquired by ingesting insect vectors. The T. wauwau-like genotype in new mammalian host species supports the 'bat seeding' hypothesis of the T. cruzi clade. The epidemiological and evolutionary implications of these findings are discussed.

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.

High-Throughput Sequencing for Trypanosome Transcriptome Characterization.

High-throughput sequencing of cDNA (RNASeq) is now the method of choice for analysis of transcriptomes. This chapter details important considerations in the design of RNASeq experiments for kinetoplastids grown in culture or experimental animals. It contains protocols for obtaining parasites from rodents, and for removal of rRNA from total RNA. In addition, custom pipelines for sequence alignment, and for data analysis and visualization, are described.

Parasitological, serological and molecular survey of camel trypanosomiasis in Somalia.

BACKGROUND: Camel trypanosomiasis or surra is of great concern in Somalia, since the country possesses the largest one-humped camel (Camelus dromedarius) population in the world. Civil war in Somalia has resulted in the destruction of educational, research, economic and social structures, making the country scores very low for most humanitarian indicators. Previous studies on detection of Trypanosoma species in Somali camels have only been performed during the 1990s using standard trypanosome detection methods (STDM). Considering the lack of state-of-the-art knowledge on camel trypanosomiasis in Somalia, the present study aimed to assess the prevalence of Trypanosoma spp. in three districts of Somalia. METHODS: A total of 182 blood samples from C. dromedarius from nomadic and dairy farms were evaluated using STDM, serological (CATT/T. evansi) and molecular (ITS1-PCR) methods. RESULTS: All samples were negative for Trypanosoma spp. by STDM. A total of 125/182 (68.7%, 95% CI: 61.4-75.3%) camels were seropositive for T. evansi by CATT/T. evansi. Camels reared in nomadic system were more likely to be seropositive for T. evansi than those under dairy production system (OR: 5.6, 95% CI: 2.1-15.2, P = 0.0001). Five out of 182 (2.7%, 95% CI: 0.9-6.3%) camels tested positive for Trypanosoma sp. by ITS1-PCR. Sequencing of the ITS1 region of the Trypanosoma species detected herein revealed that camels were infected with T. evansi and T. simiae. CONCLUSIONS: Trypanosoma evansi is highly prevalent in camels from the Banadir region of Somalia, particularly in nomadic herds. To our knowledge, this is the first study to confirm infections with T. evansi and T. simiae in Somali camels through DNA sequencing. Our data highlight the need for implementation of adequate control measures aiming to reduce the impact on camel production in the country.

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.

Development of an optical biosensor for the detection of Trypanosoma evansi and Plasmodium berghei.

A laboratory prototype system that correlates murine blood absorbance with degree of infection for Plasmodium berghei and Trypanosoma avensi has been designed, constructed and tested. A population (n = 6) of control uninfected, Plasmodium infected and Trypanosoma infected BALB/c mice were developed and spectral absorption measurements pre and post infection were made every 3 days. A fibre optic spectrometer set-up was used as the basis of a laboratory prototype biosensor that uses the Beer Lambert Law to relate Ultraviolet-Visible-Near-infrared absorbance data to changes in murine blood chemistry post infection. Spectral absorption results indicate a statistically relevant correlation at a 650 nm with infection for Plasmodium from between 4 and 7 sampling days' post infection, in spite of significant standard deviations among the sample populations for control and infected mice. No significant spectral absorption change for Trypanosoma infection was been detected from the current data. Corresponding stained slides of control and infected blood at each sampling date were taken with related infected cell counts determined and these correlate well for Plasmodium absorbance at 650 nm.

Evaluation and correlation of oxidative stress and haemato-biochemical observations in horses with natural patent and latent trypanosomosis in Punjab state of India.

The haemato-biochemical indices and oxidative stress markers in horses naturally infected with Trypanosoma evansi were evaluated by analyzing the level of these parameters between T. evansi infected (microscopically positive patent group and PCR positive latent group) and infection free horses. To compare the hemato-biochemical indices and oxidative stress indicators, horses were divided into three categories based on diagnostic test employed and positive results obtained. These included Romanowsky stained slide positive group (Group I; n = 6), PCR positive group (group II; n = 28) and negative control group (group III, n = 30), revealing parasitologically positive patent, molecular positive latent and disease free status of horses. A significant reductions in total erythrocytes count (TEC, P = 0.01), haemoglobin (Hb, P = 0.01) and packed cell volume (PCV, P = 0.04) was noticed both in group I and group II while significant neutrophilia and lymphocytopenia was observed in group I when compared to negative control group. Substantial increase in creatinine (CRTN, P = 0.032) and gamma glutamyl transferase (GGT, P = 0.012) in group I while significant decrease in glucose (GLU, P = 0.04) and iron (Fe, P = 0.01) were noticed in both group I and group II in comparison to group III. A significant difference in lipid peroxides (LPO, P = 0.01) with highest level in patent group I (15.33 ± 0.53) followed by PCR positive latent group (14.09 ± 1.66) indicates higher lipid peroxidation in erythrocytes and oxidative stress in decreasing order when compared with infection free control horses (9.83 ± 0.97). Catalase (CAT, P = 0.01) was significantly lower in parasitological (0.82 ± 0.14) and molecular positive cases (1.27 ± 0.35) in comparison to control group (3.43 ± 0.96). The levels of superoxide dismutase (SOD, P = 0.01), reduced glutathione (GSH, P = 0.01) and ferric reducing antioxidant power (FRAP, P = 0.01) were significantly lower in parasito-molecular positive cases as compared to infection free control horses. An inverse correlation of RBC count with LPO and GSH and a direct correlation with catalase, SOD and FRAP was revealed. Overall, the observed substantial decreases in the oxidative parameters like catalase CAT, SOD, GSH and FRAP activities with remarkably elevated levels of LPO indicate high exposure of erythrocytes to oxidative damage in T.evansi infected horses.

Development and validation of direct dry loop mediated isothermal amplification for diagnosis of Trypanosoma evansi.

Non-tsetse transmitted Trypanosoma evansi infection (Surra) is one of the most important diseases of camels in north and east Africa and of buffalo and cattle in Asia. Early, accurate and feasible diagnosis is a crucial step towards the control of Surra. Dry format of loop-mediated isothermal amplification (LAMP) diagnostics for the detection of T. evansi was developed, where the detection limit was determined as to equivalent to one parasite per reaction. The assay was validated by testing blood from 48 camels clinically diagnosed to have Surra, which all tested negative microscopically and revealed 43 (89.6%) to be positive for T. evansi when tested by the dry-LAMP. Furthermore, DNA extracted from a randomly selected subset of 20 of these blood samples were then subjected to RoTat1.2-PCR (TaKara Ex Taq), with 14 matching results, with six that were positive by dry-LAMP and negative by PCR. The kappa value of dry-LAMP applied to direct blood was 0.4211, indicating moderate agreement to RoTat 1.2-PCR. In addition, 103 genomic DNA extracted from camels' blood were tested by both dry-LAMP and RoTat1.2-PCR revealed 67 matching results and 31 positive by dry-LAMP and negative by PCR and a further five positives by PCR and negative by dry-LAMP. This novel dry-LAMP method is more sensitive than conventional PCR, direct (without DNA extraction step), is user friendly and does not require cold chain or highly trained personnel.

Dynamic nuclear polarization facilitates monitoring of pyruvate metabolism in Trypanosoma brucei.

Dynamic nuclear polarization provides sensitivity improvements that make NMR a viable method for following metabolic conversions in real time. There are now many in vivo applications to animal systems and even to diagnosis of human disease. However, application to microbial systems is rare. Here we demonstrate its application to the pathogenic protozoan, Trypanosoma brucei, using hyperpolarized 13C1 pyruvate as a substrate and compare the parasite metabolism with that of commonly cultured mammalian cell lines, HEK-293 and Hep-G2. Metabolic differences between insect and bloodstream forms of T. brucei were also investigated. Significant differences are noted with respect to lactate, alanine, and CO2 production. Conversion of pyruvate to CO2 in the T. brucei bloodstream form provides new support for the presence of an active pyruvate dehydrogenase in this stage.

Molecular occurrence of trypanosomes, erythrocyte and serum sialic acid concentrations of Muturu and Bunaji cattle in Benue State, Nigeria.

One hundred each, of Muturu and Bunaji cattle were screened, using polymerase chain reaction (PCR), for trypanosomes in Makurdi and Gboko Local Government Areas of Benue State, Nigeria. Erythrocyte surface sialic acid (ESSA) and free serum sialic acid (FSSA) concentrations were determined and compared in both breeds with the aim of providing baseline data for research and diagnostic purposes. Five per cent (5%) and 23% of the Muturu and Bunaji cattle, respectively, were positive for trypanosomes. The result at p=0.005 was significantly different, with p value of 0.0002 and odd ratio of 0.1762. The Trypanosoma species circulating in Benue State, as detected in the two breeds of cattle, were Trypanosoma congolense, T. vivax, T. brucei and T. evansi. This study, therefore, reports for the first time a natural infection of cattle with T. evansi and the use of a novel PCR in the diagnosis of trypanosome infections in cattle in Benue State, Nigeria. The determination of the ESSA and FSSA concentrations in Muturu cattle in Nigeria is also reported for the first time. The Muturu cattle have a significantly higher ESSA than the Bunaji cattle, this may be responsible for their relative trypanotolerance.

Epidemiological study of common diseases and their risk factors in camels in South Punjab, Pakistan.

Bacteriological study of mastitis along with common blood protozoan diseases were studied in dromedary camels in Cholistan, Dera Ismail Khan and Rahim Yar Khan districts in South Punjab, Pakistan. For this purpose 300 camels were sampled randomly at different common grazing and watering point. For study of blood parasites clinically suspected and apparently healthy camels, 150 each, were sampled. An overall prevalence of 15%and 5% was recorded for trypanosomiasis and Anaplasmosis respectively. Trypanosoma evansi was identified with 280 bp product on polymerase chain reaction test. There was significant (P < 0.05) decline in the values of total erythrocyte counts, hemoglobin concentration, packed cell volume, serum total proteins and albumin while erythrocyte sedimentation rate was increased in infected camels as compared to healthy ones. Aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase were also significantly increased in blood protozoan the infected animals. Milk samples for bacteriology were collected from healthy lactating camels (n = 100). Information about different risk factors were gathered on designed performa. Subclinical mastitis on surf field test was recorded in 42% camels while 2% cases of clinical mastitis were recorded. Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Bacillus cereus and. Corynebacterium kutscheri were isolated with characteristic beta and alpha hemolysis patterns. Chi-square analysis showed significant difference as p < 0.05 among various species of bacteria (χ2 = 21.649, P-Value = 0.0001, df = 3). Antibiogram showed Gentamicin, Norfloxacin, Oxytetracycline as most effective therapy for mastitis in camel.

Use of physiological biomarkers in diagnosis along with field trials of different trypanisidal drugs in camels of Cholistan desert.

The point prevalence of trypanosomiasis with different physiological biomarkers along with evaluation of the most responsive trypanosidal drug against trypanosomiasis under field conditions was studied. For this purpose a total of 300 free range camels were selected at different grazing and watering point in Cholistan desert. The study population of camels included 150 clinically suspected camels for trypanosomiasis and 150 healthy camels with normal temperature, pulse and respiration. For therapeutic trials 36 positively diagnosed animals were randomly divided into three experimental groups for therapeutic trials. Group A was treated with Imidocarb dipropionate (ID) @ 1.2 mg kg-1 body weight; Group B was treated with Diaminazine aceturate (DA) @ 3.5 mg kg-1 body weight and Group C was treated with Isometamidium chloride hypochloride (IC) @ 0.75 mg kg-1 body weight of camels. Data on risk factors of age,sex, ectoparasites, housing was also collected. Results revealed an overall 15% point prevalence of trypanosomiasis. There was significant (P < 0.05) decline in the values of physiological biomarkers of total erythrocyte counts, hemoglobin concentration, packed cell volume, serum total proteins and albumin while erythrocyte sedimentation rate was increased in infected camels as compared to healthy ones. Different hepatic enzymes including aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase were also significantly increased in the infected animals. Therapeutic trials indicated that Isometamidium chloride hypochloride (IC) was more effective than Imidocarb dipropionate (ID) and Diaminazine aceturate (DA). It is concluded that haemato-biochemical parameters were important physiological biomarkers and IC was the most responsive therapeutic agent against trypanosomiasis in camels in field conditions. The risk factors analysis showed older camels (>5 years) showed highest infection while infection was found to be lowest in less than 1 year age group.

Developmental and Ultrastructural Characterization and Phylogenetic Analysis of Trypanosoma herthameyeri n. sp. of Brazilian Leptodactilydae Frogs.

We described the phylogenetic affiliation, development in cultures and ultrastructural features of a trypanosome of Leptodacylus chaquensis from the Pantanal biome of Brazil. In the inferred phylogeny, this trypanosome nested into the Anura clade of the basal Aquatic clade of Trypanosoma, but was separate from all known species within this clade. This finding enabled us to describe it as Trypanosoma herthameyeri n. sp., which also infects other Leptodacylus species from the Pantanal and Caatinga biomes. Trypanosoma herthameyeri multiplies as small rounded forms clumped together and evolving into multiple-fission forms and rosettes of epimastigotes released as long forms with long flagella; scarce trypomastigotes and glove-like forms are common in stationary-phase cultures. For the first time, a trypanosome from an amphibian was observed by field emission scanning electron microscopy, revealing a cytostome opening, well-developed flagellar lamella, and many grooves in pumpkin-like forms. Transmission electron microscopy showed highly developed Golgi complexes, relaxed catenation of KDNA, and a rich set of spongiome tubules in a regular parallel arrangement to the flagellar pocket as confirmed by electron tomography. Considering the basal position in the phylogenetic tree, developmental and ultrastructural data of T. herthameyeri are valuable for evolutionary studies of trypanosome architecture and cell biology.

Changes in some pregnancy biomarkers of Yankasa ewes experimentally infected with Trypanosoma evansi.

The study was designed to determine the effect of Trypanosoma evansi infection on some pregnancy biomarkers of Yankasa ewes (YE). Twenty pregnant YE were assigned into 3 groups (A, B and C) comprising 7 ewes each in groups A and B, while group C comprise 6 YE. Groups A and B were each inoculated with blood containing approximately 1.0 × 10(6) of T. evansi through the jugular vein on days 59 and 110 of pregnancy, representing second and third trimesters, respectively, while group C served as the uninfected control. Progesterone (P4) and pregnancy specific protein-B (PSPB) of YE in group A were significantly (p < 0.05) high at weeks 4 and 12 post infection (pi) respectively, while there was no significant (p > 0.05) difference in P4 and PSPB of YE in groups B. Estrone sulfate (E1S) significantly (p < 0.05) decrease for YE in group A at weeks 2 and 11 pi. However, it was not significantly (p > 0.05) different in group B. Cortisol concentration of YE in group A was significantly (p < 0.05) decreased at week 12 pi. Conversely, the cortisol concentration of YE in group B significantly (p < 0.05) increased at week 3 pi. There was no significant (p > 0.05) association among the pregnancy biomarkers of YE in groups A and B throughout the study, except between progesterone and cortisol in group B, which were significantly associated (r = 0.77, p < 0.05). It was therefore concluded that T. evansi infection affects pregnancy biomarkers more at mid pregnancy than at late pregnancy.

Haemato-biochemical and oxidative status of buffaloes naturally infected with Trypanosoma evansi.

Blood samples were collected from 05 clinically healthy and 10 adult female water buffaloes naturally infected with Trypanosoma evansi. Confirmation of disease free and infected status of buffaloes was made on clinical signs, observation of T. evansi parasites in the blood smear and duplex PCR based assay. Blood samples were evaluated for levels of haemoglobin (Hb), packed cell volume (PCV), differential leucocytes count (DLC), lipid peroxidation (LPO), calcium, phosphorous, magnesium sodium and potassium and activities of superoxide dismutase (SOD), catalase (CAT), aspartate transaminase (AST), lactate dehydogenase (LDH) and alkaline phosphatase (ALP). The results of the study revealed substantial decrease in levels of Hb, PCV and increase in LPO, SOD, CAT and AST in infected animals compared to healthy animals. However other haematological and biochemical indices did not show significant variations in infected and healthy buffaloes. The enhanced erythrocytic oxidation and reduction of hematological indices, suggests that the enhanced oxidation of the erythrocytes may be a contributory factor in erythrocytic destruction and progression of the anaemia in T. evansi infection in water buffaloes.

Parasitological, serological and molecular survey of Trypanosoma evansi infection in dromedary camels from Cholistan Desert, Pakistan.

BACKGROUND: Surra, a vector borne disease caused by Trypanosoma (T.) evansi, affects the health, productivity and working capacity of camels. Since clinical signs are not pathognomonic, diagnosis must be confirmed by laboratory methods. This is a first study on the prevalence of surra in Cholistan Desert, Pakistan using a broad variety of diagnostic tests thereby emphasizing it as a risk for the dromedaries of Pakistan. METHODS: In a cross sectional study, 1005 dromedary camels from three districts in the Cholistan Desert were sampled to assess the prevalence of trypanosomosis due to T. evansi by means of parasitological (Giemsa stained thin smear), serological (formol gel test, CATT/T. evansi, ELISA/VSG RoTat 1.2, immune trypanolysis) and molecular tests (TBR1/2 PCR and RoTat 1.2 PCR). Kappa was calculated to assess the degree of agreement between different tests whereas chi-square test along with odds ratios and their 95% confidence intervals were used to study influence of breed, gender, age and locality on disease prevalence. RESULTS: Overall prevalence was 0.7% with Giemsa stained thin smears (GST), 40.1% with formol gel test (FGT), 47.7% with CATT/T. evansi, 44.2% with ELISA/VSG RoTat 1.2, 39.9 % with immune trypanolysis (TL), 31.9 % with TBR1/2 PCR and 30.5% with RoTat1.2 PCR. Based on these results, the Cholistan Desert appears to be a high risk area for surra. According to TL and TBR1/2 PCR, camels at Bahawalpur are approximately two times more likely to be infected than those in Bahawalnagar (OR = 1.8; 95% CI: 1.38-2.42) and Rahim Yar Khan (OR = 1.9; 95% CI: 1.30-2.75). Test agreement of TL was moderate with CATT/T. evansi (k = 0.43; 95% CI: 0.378-0.489) and ELISA/VSG RoTat 1.2 (k = 0.54; 95% CI: 0.489-0.594) and poor with the other tests. Test agreement between TBR1/2 PCR and RoTat1.2 PCR was almost perfect (k = 0.96; 95% CI: 0.950-0.984). We didn't find evidence for the presence of T. evansi type B in the studied population. CONCLUSION: Our study supports using antibody detection tests, rather than parasitological and molecular examination, to assess surra prevalence in camels. It also calls for implementation of measures to control surra in the Cholistan Desert.

Surra Sero K-SeT, a new immunochromatographic test for serodiagnosis of Trypanosoma evansi infection in domestic animals.

Trypanosoma evansi, the causative agent of surra, infects different domestic and wild animals and has a wide geographical distribution. It is mechanically transmitted mainly by haematophagous flies. Parasitological techniques are commonly used for the diagnosis of surra but have limited sensitivity. Therefore, serodiagnosis based on the detection of T. evansi specific antibodies is recommended by the World Organisation for Animal Health (OIE). Recently, we developed a new antibody detection test for the serodiagnosis of T. evansi infection, the Surra Sero K-SeT. Surra Sero K-SeT is an immunochromatographic test (ICT) that makes use of recombinant variant surface glycoprotein rVSG RoTat 1.2, produced in the yeast Pichia pastoris. In this study, we compared the diagnostic accuracy of the Surra Sero K-SeT and the Card Agglutination Test for T. evansi Trypanosomososis (CATT/T. evansi) with immune trypanolysis (TL) as reference test on a total of 806 sera from camels, water buffaloes, horses, bovines, sheep, dogs and alpacas. Test agreement was highest between Surra Sero K-SeT and TL (κ=0.91, 95% CI 0.841-0.979) and somewhat lower between CATT/T. evansi and TL (κ=0.85, 95% CI 0.785-0.922) and Surra Sero K-SeT and CATT/T. evansi (κ=0.81, 95% CI 0.742-0.878). The Surra Sero K-SeT displayed a somewhat lower overall specificity than CATT/T. evansi (94.8% versus 98.3%, χ(2)=13.37, p<0.001) but a considerably higher sensitivity (98.1% versus 84.4%, χ(2)=33.39, p<0.001). We conclude that the Surra Sero K-SeT may become an alternative for the CATT/T. evansi for sensitive detection of antibodies against T. evansi in domestic animals.