Impact of computer-aided characterization for diagnosis of colorectal lesions, including sessile serrated lesions: Multireader, multicase study.

OBJECTIVES: Computer-aided characterization (CADx) may be used to implement optical biopsy strategies into colonoscopy practice; however, its impact on endoscopic diagnosis remains unknown. We aimed to evaluate the additional diagnostic value of CADx when used by endoscopists for assessing colorectal polyps. METHODS: This was a single-center, multicase, multireader, image-reading study using randomly extracted images of pathologically confirmed polyps resected between July 2021 and January 2022. Approved CADx that could predict two-tier classification (neoplastic or nonneoplastic) by analyzing narrow-band images of the polyps was used to obtain a CADx diagnosis. Participating endoscopists determined if the polyps were neoplastic or not and noted their confidence level using a computer-based, image-reading test. The test was conducted twice with a 4-week interval: the first test was conducted without CADx prediction and the second test with CADx prediction. Diagnostic performances for neoplasms were calculated using the pathological diagnosis as reference and performances with and without CADx prediction were compared. RESULTS: Five hundred polyps were randomly extracted from 385 patients and diagnosed by 14 endoscopists (including seven experts). The sensitivity for neoplasia was significantly improved by referring to CADx (89.4% vs. 95.6%). CADx also had incremental effects on the negative predictive value (69.3% vs. 84.3%), overall accuracy (87.2% vs. 91.8%), and high-confidence diagnosis rate (77.4% vs. 85.8%). However, there was no significant difference in specificity (80.1% vs. 78.9%). CONCLUSIONS: Computer-aided characterization has added diagnostic value for differentiating colorectal neoplasms and may improve the high-confidence diagnosis rate.

Changes in halitosis value before and after Helicobacter pylori eradication: A single-institutional prospective study.

BACKGROUND AND AIM: Although patients report either improved or worsened halitosis after Helicobacter pylori eradication therapy, such complaints are subjective. Only a few studies have objectively evaluated reports of changes in halitosis after H. pylori eradication; thus, this study aimed to investigate these changes after a successful H. pylori eradication. METHODS: Between February 2015 and October 2018, 56 347 patients visited the clinic. Informed consent for participation in this study was obtained from 164 patients scheduled to undergo upper gastrointestinal endoscopy due to halitosis. Of the 91 patients with H. pylori infection, the halitosis values were evaluated as Refres breath (RB) values using a Total Gas Detector™ System and compared before and after successful H. pylori eradication, as confirmed with urea breath testing. RESULTS: Among the 91 patients treated, 77 patients were successfully eradicated of H. pylori and had their Refres values measured (21 men and 56 women; mean age, 64.2 ± 11.5 years, including 10 smokers); among these 77 patients, 27 showed RB values of > 60. Their RB values significantly improved from 73.5 Â (95% confidence interval [CI], 64.1-82.9) to 59.4 Â (95% CI, 50.0-68.8) (P = 0.038). Of the 30 patients who could be followed up for > 2 years after successful H. pylori eradication, 8 with an RB value ≥ 60 showed significant RB value improvements from 77.9 Â (95% CI, 59.4-96.4) to 30.1 Â (95% CI, 11.6-48.6) (P = 0.0016). CONCLUSIONS: Helicobacter pylori eradication therapy could improve halitosis, and such improvement could be maintained even 2 years after successful eradication.

Effectiveness of Rapid Antigen Testing in Forensic Cases of Severe Acute Respiratory Syndrome Coronavirus 2 Infection, Including Delta Variant.

ABSTRACT: The polymerase chain reaction is indispensable for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in forensic cases. However, studies regarding the effectiveness of rapid antigen testing (RAT) in forensic cases remain limited. Therefore, we investigated the efficacy of RAT compared with reverse-transcription quantitative polymerase chain reaction (RT-qPCR) for confirming SARS-CoV-2 infection (including the delta variant). Before the external examination or autopsy, we collected samples from the nasopharyngeal mucosa, which were then assessed via RAT (QuickNavi COVID-19 Ag kit, QuickNavi-Flu+COVID-19 Ag kit) and RT-qPCR. Reverse-transcription quantitative polymerase chain reaction results were positive in 73 of 1255 cases, and 21 cases were identified as those of delta variants. Low RT-qPCR threshold cycle value cases and delta variant infections were more likely to result in coronavirus disease-related deaths. The sensitivity of the QuickNavi COVID-19 Ag kit was 76.32%, and that of the QuickNavi-Flu+COVID-19 Ag kit was 77.14%. The specificity of both RATs was 100%. In QuickNavi COVID-19 Ag kit cases, delta variant cases showed lower sensitivity than non-delta variant cases, even for a similar viral load. Thus, RAT in forensic cases is sufficiently useful as a screening test for SARS-CoV-2 infection. However, RAT carries a risk of false negatives, especially for delta variant cases.

Endocytoscopic intramucosal capillary network changes and crypt architecture abnormalities can predict relapse in patients with an ulcerative colitis Mayo endoscopic score of 1.

OBJECTIVES: Recent studies have suggested the necessity of therapeutic intervention for patients with ulcerative colitis at high risk of clinical relapse with a Mayo endoscopic score (MES) of 1. The aim of this retrospective cohort study was to demonstrate the impact of intramucosal capillary network changes and crypt architecture abnormalities to stratify the risk of relapse in patients with an MES of 1. METHODS: All included patients had an MES of ≤1 and confirmed sustained clinical remission between October 2016 and April 2019. We classified patients with an MES of 1 as "intramucosal capillary/crypt (ICC)-active" or "ICC-inactive" using endocytoscopic evaluation. We followed patients until October 2019 or until relapse; the main outcome measure was the difference in clinical relapse-free rates between ICC-active and ICC-inactive patients with an MES of 1. RESULTS: We included 224 patients and analyzed data for 218 (82 ICC-active and 54 ICC-active with an MES of 1 and 82 with an MES of 0). During follow-up, among the patients with an MES of 1, 30.5% (95% confidence interval 20.8-41.6; 25/82) of the patients relapsed in the ICC-active group and 5.6% (95% confidence interval 1.2-15.4; 3/54) of the patients relapsed in the ICC-inactive group. The ICC-inactive group had a significantly higher clinical relapse-free rate compared with the ICC-active group (P < 0.01). CONCLUSIONS: In vivo intramucosal capillary network and crypt architecture patterns stratified the risk of clinical relapse in patients with an MES of 1 (UMIN 000032580; UMIN 000036359).

Management and risk factor of stenosis after endoscopic submucosal dissection for colorectal neoplasms.

BACKGROUND AND AIM: Although endoscopic submucosal dissection (ESD) enables en bloc removal of large colorectal neoplasms, the incidence of stenosis after ESD and its risk factors have not been well described. This study aimed to determine the risk factors of stenosis and verify the surveillance and treatment of stenosis. METHODS: This retrospective study included 822 patients, with a total of 912 consecutive colorectal lesions, who underwent ESD from September 2003 to May 2015. The main outcome measures were incidence of stenosis and its relationship with the clinicopathologic factors in surveillance. RESULTS: Surveillance endoscopy was performed 6 months after ESD. Four of the 822 patients (0.49%) developed stenosis and required unanticipated endoscopy. The other 908 cases in 818 patients showed no symptoms or only slight abdominal discomfort (that was controlled with medication) and did not require any dilation or steroid therapies. Post-ESD stenosis was observed in 11.1% (2/18) of patients with circumferential resection between ≥90% and <100% and in 50% (2/4) of patients with circumferential resection of 100%. Among the 50 cases with a circumferential mucosal defect ≥75%, a circumferential mucosal defect ≥90% was a significant risk factor (P = .005). Four patients with stenosis were treated successfully by endoscopic dilation. CONCLUSIONS: Circumferential mucosal defect of more than 90% is a significant risk factor for stenosis after colorectal ESD. Surveillance endoscopy 6 months after ESD is recommended to assess for development of stenosis. Defects smaller than 90% do not require close endoscopic follow-up or prophylactic measures for prevention of post-ESD stenosis. (UMIN clinical trial registration number: UMIN000015754.).

A TeGM6-4r antigen-based immunochromatographic test (ICT) for animal trypanosomosis.

Animal trypanosomosis is a disease that is distributed worldwide which results in huge economic losses due to reduced animal productivity. Endemic regions are often located in the countryside where laboratory diagnosis is costly or inaccessible. The establishment of simple, effective, and accurate field tests is therefore of great interest to the farming and veterinary sectors. Our study aimed to develop a simple, rapid, and sensitive immunochromatographic test (ICT) for animal trypanosomosis utilizing the recombinant tandem repeat antigen TeGM6-4r, which is conserved amongst salivarian trypanosome species. In the specificity analysis, TeGM6-4r/ICT detected all of Trypanosoma evansi-positive controls from experimentally infected water buffaloes. As expected, uninfected controls tested negative. All sera samples collected from Tanzanian and Ugandan cattle that were Trypanosoma congolense- and/or Trypanosoma vivax-positive by microscopic examination of the buffy coat were found to be positive by the newly developed TeGM6-4r/ICT, which was comparable to results from TeGM6-4r/ELISA (kappa coefficient [κ] = 0.78). TeGM6/ICT also showed substantial agreement with ELISA using Trypanosoma brucei brucei (κ = 0.64) and T. congolense (κ = 0.72) crude antigen, suggesting the high potential of TeGM6-4r/ICT as a field diagnostic test, both for research purposes and on-site diagnosis of animal trypanosomosis.

Association of 410L, 1016I and 1534C kdr mutations with pyrethroid resistance in Aedes aegypti from Ouagadougou, Burkina Faso, and development of a one-step multiplex PCR method for the simultaneous detection of 1534C and 1016I kdr mutations.

BACKGROUND: Since 2000, Burkina Faso has experienced regular dengue cases and outbreaks, making dengue an increasingly important health concern for the country. Previous studies in Burkina Faso reported that resistance of Aedes aegypti to pyrethroid insecticides was associated with the F1534C and V1016I kdr mutations. The current study reports high resistance of Ae. aegypti populations to pyrethroid insecticides, likely supported by mutations in the voltage-gated sodium channel, here evidenced by genotyping the kdr SNPs V410L, V1016I and F1534C. We also describe a new multiplex PCR-based diagnostic of F1534C and V1016I kdr SNPs. METHODS: Larvae of Ae. aegypti were collected from three health districts of Ouagadougou in 2018. The resistance status of Ae. aegypti to permethrin (15 µg/ml) and deltamethrin (10 µg/ml) was tested using bottles and to malathion (5%) using WHO tube tests. All bioassays used 1-h exposure and mortality recorded 24 h post-exposure. Bioassay results were interpreted according to WHO thresholds for resistance diagnosis. The kdr mutations were screened using AS-PCR and TaqMan methods in exposed and non-exposed Aedes mosquitoes. RESULTS: Females from all health districts were resistant to permethrin and deltamethrin (< 20% mortality) but were fully susceptible to 5% malathion. The F1534C and V1016I kdr mutations were successfully detected using a newly developed multiplex PCR in perfect agreement with TaqMan method. The 1534C/1016I/410L haplotype was correlated with permethrin resistance but not with deltamethrin resistance; however, the test power was limited by a low frequency of dead individuals in deltamethrin exposure. CONCLUSIONS: Resistance to pyrethroid insecticides is associated with kdr mutant haplotypes, while the absence of substantial resistance to malathion suggests that it remains a viable option for dengue vector control in Ouagadougou.

Structural characterization and epitope mapping of the glutamic acid/alanine-rich protein from Trypanosoma congolense: defining assembly on the parasite cell surface.

Trypanosoma congolense is an African trypanosome that causes serious disease in cattle in Sub-Saharan Africa. The four major life cycle stages of T. congolense can be grown in vitro, which has led to the identification of several cell-surface molecules expressed on the parasite during its transit through the tsetse vector. One of these, glutamic acid/alanine-rich protein (GARP), is the first expressed on procyclic forms in the tsetse midgut and is of particular interest because it replaces the major surface coat molecule of bloodstream forms, the variant surface glycoprotein (VSG) that protects the parasite membrane, and is involved in antigenic variation. Unlike VSG, however, the function of GARP is not known, which necessarily limits our understanding of parasite survival in the tsetse. Toward establishing the function of GARP, we report its three-dimensional structure solved by iodide phasing to a resolution of 1.65 Å. An extended helical bundle structure displays an unexpected and significant degree of homology to the core structure of VSG, the only other major surface molecule of trypanosomes to be structurally characterized. Immunofluorescence microscopy and immunoaffinity-tandem mass spectrometry were used in conjunction with monoclonal antibodies to map both non-surface-disposed and surface epitopes. Collectively, these studies enabled us to derive a model describing the orientation and assembly of GARP on the surface of trypanosomes. The data presented here suggest the possible structure-function relationships involved in replacement of the bloodstream form VSG by GARP as trypanosomes differentiate in the tsetse vector after a blood meal.

Dimiconin, a novel coagulation inhibitor from the kissing bug, Triatoma dimidiata, a vector of Chagas disease.

Sequence analysis of a Triatoma dimidiata salivary gland cDNA library resulted in the identification of two transcripts (Td60 and Td101) homologous to triabin, an inhibitor of thrombin in Triatoma pallidipennis saliva. In the present study, a recombinant protein of Td60, designated dimiconin, was expressed in Escherichia coli and its activity was characterized. The resulting protein inhibited the intrinsic but not extrinsic blood coagulation pathway, suggesting that dimiconin is not a thrombin inhibitor. Measurement of the enzymatic activity of coagulation factors using chromogenic substrates revealed that dimiconin efficiently inhibited factor XIIa (FXIIa) activity in a dose-dependent manner. In addition, pre-incubation of dimiconin with FXII effectively inhibited FXIIa activity whereas dimiconin did not affect already activated FXIIa, indicating that dimiconin inhibits the activation of FXII but not the enzymatic activity of FXIIa. These results show that dimiconin is an inhibitor of the contact phase initiated by FXII activation in the blood coagulation cascade, which differs from the bioactivity of triabin.

Nitrogen burden from atmospheric deposition in East Asian oceans in 2010 based on high-resolution regional numerical modeling.

East Asian oceans are possibly affected by a high nitrogen (N) burden because of the intense anthropogenic emissions in this region. Based on high-resolution regional chemical transport modeling with horizontal grid scales of 36 and 12 km, we investigated the N burden into East Asian oceans via atmospheric deposition in 2010. We found a high N burden of 2-9 kg N ha-1 yr-1 over the Yellow Sea, East China Sea (ECS), and Sea of Japan. Emissions over East Asia were dominated by ammonia (NH3) over land and nitrogen oxides (NOx) over oceans, and N deposition was dominated by reduced N over most land and open ocean, whereas it was dominated by oxidized N over marginal seas and desert areas. The verified numerical modeling identified that the following processes were quantitatively important over East Asian oceans: the dry deposition of nitric acid (HNO3), NH3, and coarse-mode (aerodynamic diameter greater than 2.5 µm) NO3-, and wet deposition of fine-mode (aerodynamic diameter less than 2.5 µm) NO3- and NH4+. The relative importance of the dry deposition of coarse-mode NO3- was higher over open ocean. The estimated N deposition to the whole ECS was 390 Gg N yr-1; this is comparable to the discharge from the Yangtze River to the ECS, indicating the significant contribution of atmospheric deposition. Based on the high-resolution modeling over the ECS, a tendency of high deposition in the western ECS and low deposition in the eastern ECS was found, and a variety of deposition processes were estimated. The dry deposition of coarse-mode NO3- and wet deposition of fine-mode NH4+ were the main factors, and the wet deposition of fine-mode NO3- over the northeastern ECS and wet deposition of coarse-mode NO3- over the southeastern ECS were also found to be significant processes determining N deposition over the ECS.

Trends of sulfur and nitrogen deposition from 2003 to 2017 in Japanese remote areas.

Emissions of sulfur (S) and nitrogen (N) compounds in East Asia has drastically changed over the last two decades. To assess the influence of the drastic changes in air pollution on ecosystems in Japan, we investigated the trends of S and N deposition during 2003-2017 at remote sites of Acid Deposition Monitoring Network in East Asia (EANET). We measured wet deposition and inferentially estimated dry deposition of S and N using monitoring data from 2003 to 2017 at eight sites. We estimated dry deposition using the inferential method with an updated parameterization for gaseous surface resistance. The linear regression method and nonparametric Mann-Kendall test was used to analyze the temporal trends based on the monthly data sets. High S and N deposition amounts over 10 kg ha-1 year-1 were frequently found at most sites. There were significant increase trends in N deposition to S deposition (N/S) ratio at all sites throughout the 15-year period. Some trends were significantly found when the 15-year period was divided into three: 2003-2007, 2008-2012, and 2013-2017. S deposition had significantly decreased over a wide area in Japan, especially at Sado-seki, Happo, Oki, Hedo, and Ogasawara, in 2013-2017. Significant decreases in oxidized N deposition at Sado-seki and Oki were also found in 2013-2017. Because of almost flat N deposition mainly contributed by reduced N deposition, the N/S ratio clearly increased. These trends were associated with the recent reductions in SO2 and NOx emissions in China. The NOx emission reduction of China has not caught up with that of SO2, and NH3 emissions have not been reduced. This caused the significant increases in the N/S ratio not only in 2013-2017 but also in 2003-2017.

Safety and tolerability of medicinal parasite ova (Trichuris suis) in healthy Japanese volunteers: A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Trichuris suis ova (TSO), with the potential to modulate the human immune system, have been tested for therapeutic application in autoimmune and allergic diseases such as inflammatory bowel disease (IBD). Previous clinical studies were limited to European and American participants, whereas Asian populations have not been well documented. In this study, a clinical trial was conducted to examine the safety and tolerability of TSO administration among a healthy Japanese population. METHODS: The study was a randomized, double-blind, placebo-controlled trial held at Jikei University Hospital, Tokyo. Twelve volunteers were stratified into three groups receiving different doses of TSO (TSO 1000, 2500, and 7500) and another into the control group. These cases were limited to healthy Japanese men aged over 20 years old. Single doses of medicinal TSO or placebo were given to three participants of each group. All participants were followed up to 56 days after ingestion. During the follow-up period, clinical practitioners checked each participant at the clinic at 7, 14, 28, and 56 days post-ingestion (dpi). Clinical symptoms were evaluated using questionnaire-based self-reporting, which participants filled at every visit. Blood samples were drawn at 7, 14, 28, and 56 dpi. Fecal samples were collected at 28 and 56 dpi. RESULTS: During the study period, twelve healthy Japanese male volunteers were enrolled. All participants completed the follow-up period. No severe adverse events were observed during the study period in all groups. Three participants in the TSO 1000, 2500, and 7500 groups had mild to moderate abdominal symptoms, diarrhea, bloating, and appetite loss during the observation period. One participant in the placebo group presented with mild diarrhea. Microscopic examination identified no parasite ova in any fecal samples. Blood sample examination indicated elevated eosinophil count in several cases, especially in the groups with the higher dose of TSO. No extra-abdominal symptoms were present in all cases. CONCLUSIONS: Healthy Japanese people tolerated all doses of TSO without any severe adverse events. On the other hand, mild to moderate abdominal symptoms were observed in several participants. This study suggested that the medicinal use of TSO in Japan is relatively safe, and close follow-up is recommended for sustainable usage.

A method of sequential liquid dispensing for the multiplexed genetic diagnosis of viral infections in a microfluidic device.

In this study, we introduce polydimethylsiloxane (PDMS)-based microfluidic devices capable of sequential dispensing of samples into multiple reaction microchambers in a single operation to provide a fast and easy sample-to-answer platform for multiplexed genetic diagnosis of multiple viral infectious diseases. This approach utilizes the loop-mediated isothermal amplification (LAMP) method to amplify and detect specific nucleic acid (DNA/RNA) targets. We present a microfluidic flow control theory for sequential liquid dispensing phenomena, which provides design guidelines for device optimization. The device specifications, such as the possible dispensing number and maximal allowable flow rate, can be theoretically designed by optimizing the geometric dimensions of the microchannels and a pair of passive stop valves integrated into each microchamber together with the water contact angles of the materials used to fabricate the microfluidic devices. In addition, a passive stop valve with a vertical-type phaseguide structure was designed to improve device performance. We could simultaneously diagnose coronavirus disease 2019 (COVID-19) and other infectious diseases, such as severe acute respiratory syndrome (SARS), seasonal influenza A, and pandemic influenza A (H1N1) 2009. The colorimetric reverse transcription LAMP (RT-LAMP) assay suggests that the four viral infectious diseases can be detected within 30 min using a hue-based quantitative analysis, and the naked eye using our microfluidic devices.

Evaluation of Myanmar medicinal plant extracts for antitrypanosomal and cytotoxic activities.

Current chemotherapeutic options for African trypanosomiasis in humans and livestock are very limited. In the present study, a total of 71 medicinal plant specimens from 60 plant species collected in Myanmar were screened for antitrypanosomal activity against trypomastigotes of Trypanosoma evansi and cytotoxicity against MRC-5 cells in vitro. The methanol extract of dried rootbark of Vitis repens showed the highest antitrypanosomal activity with IC(50) value of 8.6 +/- 1.5 microg/ml and the highest selectivity index of 24.4. The extracts of Brucea javanica, Vitex arborea, Eucalyptus globulus and Jatropha podagrica had also remarkable activity with IC(50) values and selectivity indices in the range of 27.2-52.6 microg/ml and 11.4-15.1 respectively.

Intensive diagnostic management of coronavirus disease 2019 (COVID-19) in academic settings in Japan: challenge and future.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first emerged in Wuhan, China, and has spread globally to most countries. In Japan, the first COVID-19 patient was identified on January 15, 2020. By June 30, the total number of patients diagnosed with COVID-19 reached 18,000. The impact of molecular detection of pathogens is significant in acute-care settings where rapid and accurate diagnostic measures are critical for decisions in patient treatment and outcomes of infectious diseases. Polymerase chain reaction (PCR)-based methods, such as quantitative PCR (qPCR), are the most established gene amplification tools and have a comprehensive range of clinical applications, including detecting a variety of pathogens, even novel agents causing emerging infections. Because SARS-CoV-2 contains a single-stranded RNA genome, reverse-transcription qPCR (RT-qPCR) has been broadly employed for rapid and sensitive quantitative measurements of viral RNA copy numbers. The RT-qPCR method, however, still requires time-consuming reactions with two different enzymes in addition to isolation of RNA from patient samples, limiting the numbers of testing institutions for diagnosing SARS-CoV-2 infection. Japan is known to have performed a relatively small number of PCR tests as well as confirmed cases among developed nations; as of June 30, 2020, approximately 390,000 people in Japan had undergone PCR tests. Given the devastating impact on medical services and the scale of demand for diagnostic testing of COVID-19, it has been proposed that academic settings such as basic research departments in university/college can be engaged in diagnosing, especially in university hospitals or academic medical centers. In collaboration with established diagnostic laboratories, academic facilities can divert their function to detecting virus from patients with suspected COVID-19, adopting existing specialized expertise in virus handling, molecular work, and data analysis. This in-house testing strategy facilitates the rapid diagnosing of thousands of samples per day and reduces sample turnaround time from 1 week to less than 24 h. This review provides an overview of the general principles, diagnostic value, and limitations of COVID-19 diagnosis platforms in Japan, in particular in-house testing at academic settings.

Establishment of an in vitro transgene expression system in epimastigotes of Trypanosoma congolense.

Trypanosoma congolense epimastigote forms (EMFs) adhere to the tsetse fly proboscis, proliferate, and differentiate into animal-infective metacyclic forms (MCFs). This differentiation step, called metacyclogenesis, is indispensable for the cyclical transmission of the parasite. Although an in vitro metacyclogenesis culture system was established several decades ago, few genetic tools have been utilized to investigate the molecular mechanisms underlying T. congolense metacyclogenesis. This study established a transgene expression system using an in vitro derived EMF of T. congolense IL3000, and the transgenic EMF successfully underwent metacyclogenesis in vitro. The newly constructed expression vector pSAK was designed for integration into the alpha-beta tubulin locus, which is tandemly arranged in the T. congolense genome. The expression cassette of pSAK/enhanced green fluorescent protein (eGFP) was transfected into the EMF by electroporation. An EMF expressing eGFP was successfully generated and differentiated into an MCF that constitutively expressed eGFP. The in vitro metacyclogenesis system in combination with the transgenic EMF technique will be important tools to investigate the molecular mechanisms of metacyclogenesis.

Cloning and characterization of peroxiredoxin in Babesia bovis.

We have identified the 2-Cys peroxiredoxin (Prx) from a bovine Babesia parasite, B. bovis. Prx is a recently described family of antioxidant enzymes that are highly conserved in eukaryotes and prokaryotes. B. bovis 2-Cys Prx (BbTPx-1) contained two conserved cysteine residues that corresponded to Cys47 and Cys170 of the yeast Prx and the amino acid sequences of two catalytic domains showed significant similarities to those of mammalian typical 2-Cys Prx. The antioxidant activity of the recombinant BbTPx-1 protein expressed in E. coli was demonstrated by a thiol mixed-function oxidation assay. Furthermore, we confirmed that BbTPx-1 was expressed in the cytoplasm of intra-erythrocytic B. bovis merozites. These results suggest that B. bovis likely uses TPx-1 as a way to reduce peroxides as a control of its intracellular redox balance so that it can live and grow in the host cell.

A field study to estimate the prevalence of bovine African Trypanosomosis in Butaleja District, Uganda.

Prevalence of bovine trypanosomosis was determined from a total of 203 blood samples collected from Butaleja district, eastern Uganda. All samples were examined by microhematocrit centrifuge test (MHC), PCR and ELISA. ELISA was performed in accordance with the OIE standard procedures using Trypanosoma brucei gambiense procyclic form crude antigens. PCR were utilized to identify the species and the subspecies of trypanosome. The overall prevalence of bovine African trypanosomosis was 8.9% by MHC, and 45.3% by the ELISA. Since substantial number (12 out of 18) of MHC positive samples were negative in the PCR tests, we could not conclude the most epidemic trypanosome species in the studied area. Nevertheless, the PCR results suggests that the most prevalent trypanosome was T. b. brucei (31/203), followed by T. congolense (6/203). In addition, only a few (3/203) mixed infections of T. b. brucei and T. congolense was detected by the PCR. Results obtained from this study indicates that bovine trypanosomosis is endemic in Butaleja district, Uganda.

High frequencies of F1534C and V1016I kdr mutations and association with pyrethroid resistance in Aedes aegypti from Somgandé (Ouagadougou), Burkina Faso.

BACKGROUND: Resistance to pyrethroid insecticides involving kdr mutations is widespread in Aedes aegypti (L.) (Diptera: Culicidae) and potentially could impact control efforts in endemic countries. Dengue cases had been sporadic in Burkina Faso for over a decade prior to the 2016-2017 outbreak that resulted in 15,074 suspected cases and 36 deaths, mainly in Ouagadougou. These outbreaks highlighted the lack of information on numerous aspects of the biology, behaviour and insecticide status of local dengue vector populations that are fundamental to vector control. RESULTS: We investigated the insecticide resistance profiles and the kdr mutations involved in pyrethroid resistance of Ae. aegypti from Somgandé, a district of Ouagadougou. WHO bioassays revealed that the local Ae. aegypti populations were highly resistant to pyrethroids with mortalities of 15% for permethrin and 37% for deltamethrin. Resistance to carbamates was also detected with mortalities of 55% for propoxur and 90% for bendiocarb, but high mortalities (> 97%) to organophosphates (malathion and fenitrothion) indicated susceptibility. Allele-specific PCR and voltage-gated sodium channel gene sequencing showed a very high frequency (97%) of the F1534C kdr allele whilst the V1016I kdr mutation frequency was 46%. Association of dual-locus kdr mutations was detected for permethrin resistance. CONCLUSION: We conclude that in this locality of Burkina Faso, Ae. aegypti is resistant to pyrethroid and carbamate insecticides but remains susceptible to organophosphates, providing useful information for possible future control.

Identification and molecular characterization of a novel stage-specific surface protein of Trypanosoma congolense epimastigotes.

The cattle pathogen Trypanosoma congolense expresses life cycle stage-specific surface molecules involved in adaptation to different host and vector environments. Here we report the discovery and molecular characterization of a novel stage-specific GPI-anchored surface glycoprotein that is selectively expressed in the epimastigote (EMF) life cycle stage of T. congolense. Culture supernatants of EMF but not of procyclic culture forms (PCFs) promoted adhesion of PCF parasites in an in vitro assay. Biosynthetic labeling experiments showed that these EMF culture supernatants contained a 100kDa trypanosome-derived protein that was not present in supernatants from PCF. We named this molecule "congolense epimastigote-specific protein" (CESP). The gene encoding CESP was isolated from an EMF cDNA library after immunoscreening. The multicopy gene had a 2070-bp open reading frame that encodes a polypeptide of 689 amino acids with a predicted mass of 72.9kDa. The discrepancy between the predicted (72.9kDa) and observed (100kDa) masses may be explained partially by glycosylation of the molecule which has six potential N-glycosylation sites and a predicted GPI anchor. Indeed, metabolic labeling of CESP with [(3)H] ethanolamine revealed that CESP was a GPI-anchored protein. Confocal laser scanning microscopy showed that CESP was expressed only on the surface of the EMF stage of the parasite. The identification of CESP as a unique component of culture supernatants from EMF and that such supernatants can confer plastic-adhesive ability on PCF suggest that CESP is worth further investigation as an adhesion molecule that perhaps allows T. congolense EMF to adhere to the tsetse proboscis.