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Background: Human African Trypanosomiasis (HAT) is a neglected disease targeted for elimination as a public health problem by 2020. Elimination requires a better understanding of the epidemiology and clinical evolution of HAT. In addition to the classical clinical evolution of HAT, asymptomatic carriers and spontaneous cure have been reported in West Africa. A genetic component to human susceptibility to HAT has been suggested to explain these newly observed responses to infection. In order to test for genetic associations with infection response, genetic polymorphism in 17 genes were tested (APOL1, IL1B, IL4, IL4R, IL6, IL8, IL12B, IL12RB1, IL10, TNFA, INFG, MIF, HLA-G, HLA-A, HP, HPR and CFH). Methodology: A case-control study was performed on 180 blood samples collected from 56 cases and 124 controls from Cameroon. DNA was extracted from blood samples. After quality control, 25 samples (24 controls and 1 case) were eliminated. The genotyping undertaken on 155 individuals including 55 cases and 100 controls were investigated at 96 loci (88 SNPs and 8 indels) located on 17 genes. Associations between these loci and HAT were estimated via a case-control association test. Results: Analyses of 64 SNPs and 4 indels out of 96 identified in the selected genes reveal that the minor allele (T) of rs8062041 in haptoglobin (HP) appeared to be protective against HAT (p = 0.0002395, OR 0.359 (CI95 [0.204–0.6319])); indicating higher frequency in cases compared to controls. This minor allele with adjusted p value of 0.0163 is associated with a lower risk (protective effect) of developing sleeping sickness. Conclusion: The haptoglobin related protein HPR and HP are tightly linked and both are duplicated in some people and may lead to higher activity. This increased production could be responsible of the protection associated with rs8062041 even though this SNP is within HP. [ABSTRACT FROM AUTHOR]

Human African Trypanosomiasis (HAT) or sleeping sickness is a Neglected Tropical Disease. Long regarded as an invariably fatal disease, there is increasing evidence that infection by T. b. gambiense can result in a wide range of clinical outcomes, including latent infections, which are long lasting infections with no parasites detectable by microscopy. The determinants of this clinical diversity are not well understood but could be due in part to parasite or host genetic diversity in multiple genes, or their interactions. A candidate gene association study was conducted in Côte d’Ivoire using a case-control design which included a total of 233 subjects (100 active HAT cases, 100 controls and 33 latent infections). All three possible pairwise comparisons between the three phenotypes were tested using 96 SNPs in16 candidate genes (IL1, IL4, IL4R, IL6, IL8, IL10, IL12, IL12R, TNFA, INFG, MIF, APOL1, HPR, CFH, HLA-A and HLA-G). Data from 77 SNPs passed quality control. There were suggestive associations at three loci in IL6 and TNFA in the comparison between active cases and controls, one SNP in each of APOL1, MIF and IL6 in the comparison between latent infections and active cases and seven SNP in IL4, HLA-G and TNFA between latent infections and controls. No associations remained significant after Bonferroni correction, but the Benjamini Hochberg false discovery rate test indicated that there were strong probabilities that at least some of the associations were genuine. The excess of associations with latent infections despite the small number of samples available suggests that these subjects form a distinct genetic cluster different from active HAT cases and controls, although no clustering by phenotype was observed by principle component analysis. This underlines the complexity of the interactions existing between host genetic polymorphisms and parasite diversity. [ABSTRACT FROM AUTHOR]

Background: Human African trypanosomiasis (HAT), a lethal disease induced by Trypanosoma brucei gambiense, has a range of clinical outcomes in its human host in West Africa: an acute form progressing rapidly to second stage, spontaneous self-cure and individuals able to regulate parasitaemia at very low levels, have all been reported from endemic foci. In order to test if this clinical diversity is influenced by host genetic determinants, the association between candidate gene polymorphisms and HAT outcome was investigated in populations from HAT active foci in Guinea. Methodology and results: Samples were collected from 425 individuals; comprising of 232 HAT cases, 79 subjects with long lasting positive and specific serology but negative parasitology and 114 endemic controls. Genotypes of 28 SNPs in eight genes passed quality control and were used for an association analysis. IL6 rs1818879 allele A (p = 0.0001, OR = 0.39, CI95 = [0.24–0.63], BONF = 0.0034) was associated with a lower risk of progressing from latent infection to active disease. MIF rs36086171 allele G seemed to be associated with an increased risk (p = 0.0239, OR = 1.65, CI95 = [1.07–2.53], BONF = 0.6697) but did not remain significant after Bonferroni correction. Similarly MIF rs12483859 C allele seems be associated with latent infections (p = 0.0077, OR = 1.86, CI95 = [1.18–2.95], BONF = 0.2157). We confirmed earlier observations that APOL1 G2 allele (DEL) (p = 0.0011, OR = 2.70, CI95 = [1.49–4.91], BONF = 0.0301) is associated with a higher risk and APOL1 G1 polymorphism (p = 0.0005, OR = 0.45, CI95 = [0.29–0.70], BONF = 0.0129) with a lower risk of developing HAT. No associations were found with other candidate genes. Conclusion: Our data show that host genes are involved in modulating Trypanosoma brucei gambiense infection outcome in infected individuals from Guinea with IL6 rs1818879 being associated with a lower risk of progressing to active HAT. These results enhance our understanding of host-parasite interactions and, ultimately, may lead to the development of new control tools. [ABSTRACT FROM AUTHOR]

Background: The analysis of humoral responses directed against the saliva of blood-sucking arthropods was shown to provide epidemiological biomarkers of human exposure to vector-borne diseases. However, the use of whole saliva as antigen presents several limitations such as problems of mass production, reproducibility and specificity. The aim of this study was to design a specific biomarker of exposure to tsetse flies based on the in silico analysis of three Glossina salivary proteins (Ada, Ag5 and Tsgf1) previously shown to be specifically recognized by plasma from exposed individuals. Methodology/Principal Findings: Synthetic peptides were designed by combining several linear epitope prediction methods and Blast analysis. The most specific peptides were then tested by indirect ELISA on a bank of 160 plasma samples from tsetse infested areas and tsetse free areas. Anti-Tsgf118–43 specific IgG levels were low in all three control populations (from rural Africa, urban Africa and Europe) and were significantly higher (p<0.0001) in the two populations exposed to tsetse flies (Guinean HAT foci, and South West Burkina Faso). A positive correlation was also found between Anti-Tsgf118–43 IgG levels and the risk of being infected by Trypanosoma brucei gambiense in the sleeping sickness foci of Guinea. Conclusion/Significance: The Tsgf118–43 peptide is a suitable and promising candidate to develop a standardize immunoassay allowing large scale monitoring of human exposure to tsetse flies in West Africa. This could provide a new surveillance indicator for tsetse control interventions by HAT control programs. Author Summary: Increasing interest is paid to blood-sucking arthropod's salivary antigens to develop host direct biomarkers of exposure. Nevertheless use of whole saliva is problematic both because of mass production and specificity issues. Here, we describe an in silico approach we used to identify potential epitopes on the amino acid sequence of three tsetse salivary proteins (Ada, Ag5 and Tsgf1) that were previously shown to be specifically recognized by antibodies from exposed individuals. Three candidate peptides were synthesized and evaluated on a set of plasma collected in different tsetse-infested and tsetse-free areas. The Tsgf118–43 synthetic peptide appeared as a promising candidate to assess human exposure to tsetse flies as antibody responses were low in all three control groups and were significantly higher in our two exposed groups. Significantly higher anti- Tsgf118–43 responses were also observed in sleeping sickness patients as compared to uninfected controls suggesting that Tsgf118–43 may be used both to assess human tsetse contacts and the risk of infection by trypanosomes. This new sero-epidemiological tool could thus help National Control Programs to quickly map human exposure levels in order to better target vector control efforts and monitor vector control efficiency. [ABSTRACT FROM AUTHOR]

Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II) and without (stage I) brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II), 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested) showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology. [ABSTRACT FROM AUTHOR]

Trypanosoma brucei gambiense ( T. b. gambiense ) is the major causative agent of human African trypanosomiasis (HAT). A great variety of clinical outcomes have been observed in West African foci, probably due to complex host-parasite interactions. In order to separate the roles of parasite genetic diversity and host variability, we have chosen to precisely characterize the pathogenicity and virulence of T. b. gambiense field isolates in a mouse model. Thirteen T. b. gambiense strains were studied in experimental infections, with 20 Balb/C infected mice per isolate. Mice were monitored for 30 days, in which mortality, parasitemia, anemia, and weight were recorded. Mortality rate, prepatent period, and maximum parasitemia were estimated, and a survival analysis was performed to compare strain pathogenicity. Mixed models were used to assess parasitemia dynamics, weight, and changes in Packed Cell Volume (PCV). Finally, a multivariate analysis was performed to infer relationships between all variables. A large phenotypic diversity was observed. Pathogenicity was highly variable, ranging from strains that kill their host within 9 days to a non-pathogenic strain (no deaths during the experiment). Virulence was also variable, with maximum parasitemia values ranging from 42 million to 1 billion trypanosomes/ml. Reduced PCV and weight occurred in the first two weeks of the infection, with the exception of two strains. Finally, the global analysis highlighted three groups of strains: a first group with highly pathogenic strains showing an early mortality associated with a short prepatent period; a second group of highly virulent strains with intermediate pathogenicity; and a third group of isolates characterized by low pathogenicity and virulence patterns. Such biological differences could be related to the observed clinical diversity in HAT. A better understanding of the biological pathways underlying the observed phenotypic diversity could thus help to clarify the complex nature of the host-parasite interactions that determine the resistance/susceptibility status to T. brucei gambiense . [ABSTRACT FROM AUTHOR]

Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II) and without (stage I) brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II), 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested) showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of gambiense human African trypanosomiasis (gHAT) typically involves 2 steps: a serological screen, followed by the detection of living trypanosome parasites in the blood or lymph node aspirate. Live parasites can, however, remain undetected in some seropositive individuals, who, we hypothesize, are infected with Trypanosoma brucei gambiense parasites in their extravascular dermis., Methods: To test this hypothesis, we conducted a prospective observational cohort study in the gHAT focus of Forecariah, Republic of Guinea. Of the 5417 subjects serologically screened for gHAT, 66 were enrolled into our study and underwent a dermatological examination. At enrollment, 11 seronegative, 8 unconfirmed seropositive, and 18 confirmed seropositive individuals had blood samples and skin biopsies taken and examined for trypanosomes by molecular and immunohistological methods., Results: In seropositive individuals, dermatological symptoms were significantly more frequent, relative to seronegative controls. T.b. gambiense parasites were present in the blood of all confirmed cases (n = 18) but not in unconfirmed seropositive individuals (n = 8). However, T. brucei parasites were detected in the extravascular dermis of all unconfirmed seropositive individuals and all confirmed cases. Skin biopsies of all treated cases and most seropositive untreated individuals progressively became negative for trypanosomes 6 and 20 months later., Conclusions: Our results highlight the skin as a potential reservoir for African trypanosomes, with implications for our understanding of this disease's epidemiology in the context of its planned elimination and underlining the skin as a novel target for gHAT diagnostics., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America.)

Introduction: from a genetic point of view P. falciparumis extremely polymorphic. There is a variety of parasite strains infesting individuals living in malaria endemic areas. The purpose of this study is to investigate the relationship between polymorphisms in Plasmodium falciparum parasites and Pfcrt and Pfmdr1 gene mutations in Nanoro area, Burkina Faso., Methods: blood samples from plasmodium carriers residing in the Nanoro Health District were genotyped using nested PCR. Parasite gene mutations associated with resistance to antimalarial drugs were detected by PCR-RFLP., Results: samples of 672 patients were successfully genotyped. No msp1and msp2allelic families exhibited an increase in developing mutations in resistance genes. However, mutant strains of these genes were present at greater levels in monoclonal infections than in multi-clonal infections., Conclusion: this study provides an overview of the relationship between polymorphisms in Plasmodium falciparum parasites and mutations in resistance genes. These data will undoubtedly contribute to improving knowledge of the parasite´s biology and its mechanisms of resistance to antimalarial drugs., Competing Interests: Les auteurs ne déclarent aucun conflit d´intérêts., (Copyright: Paul Sondo et al.)

Background: Human African trypanosomiasis (HAT) is a protozoal disease transmitted by tsetse flies. Infection with trypanosomes can lead directly to active HAT or latent infection with no detectable parasites, which may progress to active HAT or to spontaneous self-cure. Genetic variation could explain these differences in the outcome of infection. To test this hypothesis, polymorphisms in 17 candidate genes were tested ( APOL1 [ G1 and G2 ], CFH, HLA-A, HPR, HP, IL1B, IL12B, IL12RB1, IL10, IL4R, MIF, TNFA , IL6, IL4, IL8, IFNG , and HLA-G ). Methods: Samples were collected in Democratic Republic of the Congo. 233 samples were genotyped: 100 active HAT cases, 33 from subjects with latent infections and 100 negative controls. Commercial service providers genotyped polymorphisms at 96 single nucleotide polymorphisms (SNPs) on 17 genes. Data were analyzed using Plink V1.9 software and R. Loci, with suggestive associations (uncorrected p < 0.05) validated using an additional 594 individuals, including 164 cases and 430 controls. Results: After quality control, 87 SNPs remained in the analysis. Two SNPs in IL4 and two in IFNG were suggestively associated (uncorrected p<0.05) with a differential risk of developing a Trypanosoma brucei gambiense infection in the Congolese population. The IFNG minor allele (rs2430561, rs2069718) SNPs were protective in comparison between latent infections and controls. Carriers of the rs2243258&#95;T and rs2243279&#95;A alleles of IL4 and the rs2069728&#95;T allele of IFNG had a reduced risk of developing illness or latent infection, respectively. None of these associations were significant after Bonferroni correction for multiple testing. A validation study using more samples was run to determine if the absence of significant association was due to lack of power. Conclusions: This study showed no evidence of an association of HAT with IL4 and IFNG SNPs or with APOL1 G1 and G2 alleles, which have been found to be protective in other studies., Competing Interests: No competing interests were disclosed., (Copyright: © 2020 Fataki Asina O et al.)

Infection by Trypanosoma brucei gambiense is characterized by a wide array of clinical outcomes, ranging from asymptomatic to acute disease and even spontaneous cure. In this study, we investigated the association between macrophage migrating inhibitory factor (MIF), an important pro-inflammatory cytokine that plays a central role in both innate and acquired immunity, and disease outcome during T. b. gambiense infection. A comparative expression analysis of patients, individuals with latent infection and controls found that MIF had significantly higher expression in patients (n = 141; 1.25 ± 0.07; p < .0001) and latent infections (n = 25; 1.23 ± 0.13; p = .0005) relative to controls (n = 46; 0.94 ± 0.11). Furthermore, expression decreased significantly after treatment (patients before treatment n = 33; 1.40 ± 0.18 versus patients after treatment n = 33; 0.99 ± 0.10, p = .0001). We conducted a genome wide eQTL analysis on 29 controls, 128 cases and 15 latently infected individuals for whom expression and genotype data were both available. Four loci, including one containing the chemokine CXCL13, were found to associate with MIF expression. Genes at these loci are candidate regulators of increased expression of MIF after infection. Our study is the first data demonstrating that MIF expression is elevated in T. b. gambiense-infected human hosts but does not appear to contribute to pathology., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Human African Trypanosomiasis (HAT) is a neglected disease targeted for elimination as a public health problem by 2020. Elimination requires a better understanding of the epidemiology and clinical evolution of HAT. In addition to the classical clinical evolution of HAT, asymptomatic carriers and spontaneous cure have been reported in West Africa. A genetic component to human susceptibility to HAT has been suggested to explain these newly observed responses to infection. In order to test for genetic associations with infection response, genetic polymorphism in 17 genes were tested (APOL1, IL1B, IL4, IL4R, IL6, IL8, IL12B, IL12RB1, IL10, TNFA, INFG, MIF, HLA-G, HLA-A, HP, HPR and CFH)., Methodology: A case-control study was performed on 180 blood samples collected from 56 cases and 124 controls from Cameroon. DNA was extracted from blood samples. After quality control, 25 samples (24 controls and 1 case) were eliminated. The genotyping undertaken on 155 individuals including 55 cases and 100 controls were investigated at 96 loci (88 SNPs and 8 indels) located on 17 genes. Associations between these loci and HAT were estimated via a case-control association test., Results: Analyses of 64 SNPs and 4 indels out of 96 identified in the selected genes reveal that the minor allele (T) of rs8062041 in haptoglobin (HP) appeared to be protective against HAT (p = 0.0002395, OR 0.359 (CI95 [0.204-0.6319])); indicating higher frequency in cases compared to controls. This minor allele with adjusted p value of 0.0163 is associated with a lower risk (protective effect) of developing sleeping sickness., Conclusion: The haptoglobin related protein HPR and HP are tightly linked and both are duplicated in some people and may lead to higher activity. This increased production could be responsible of the protection associated with rs8062041 even though this SNP is within HP.

Background: Important control efforts have led to a significant reduction of the prevalence of human African trypanosomiasis (HAT) in Côte d'Ivoire, but the disease is still present in several foci. The existence of an animal reservoir of Trypanosoma brucei gambiense may explain disease persistence in these foci where animal breeding is an important source of income but where the prevalence of animal African trypanosomiasis (AAT) is unknown. The aim of this study was to identify the trypanosome species circulating in domestic animals in both Bonon and Sinfra HAT endemic foci., Methodology/principal Findings: 552 domestic animals (goats, pigs, cattle and sheep) were included. Blood samples were tested for trypanosomes by microscopic observation, species-specific PCR for T. brucei sl, T. congolense, T. vivax and subspecies-specific PCR for T. b. gambiense and T. b. gambiense immune trypanolysis (TL). Infection rates varied significantly between animal species and were by far the highest in pigs (30%). T. brucei s.l was the most prevalent trypanosome species (13.7%) followed by T. congolense. No T. b. gambiense was identified by PCR while high TL positivity rates were observed using T. b. gambiense specific variants (up to 27.6% for pigs in the Bonon focus)., Conclusion: This study shows that domestic animals are highly infected by trypanosomes in the studied foci. This was particularly true for pigs, possibly due to a higher exposure of these animals to tsetse flies. Whereas T. brucei s.l. was the most prevalent species, discordant results were obtained between PCR and TL regarding T. b. gambiense identification. It is therefore crucial to develop better tools to study the epidemiological role of potential animal reservoir for T. b. gambiense. Our study illustrates the importance of "one health" approaches to reach HAT elimination and contribute to AAT control in the studied foci.

Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II) and without (stage I) brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II), 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested) showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.