Nick Van Reet

Institute Of Tropical Medicine · Department of Biomedical Sciences

Trypanosoma brucei (T.b.) gambiense causes the chronic form of human African trypanosomiasis or sleeping sickness. One of the major problems with studying T.b. gambiense is the difficulty to isolate it from its original host and the difficult adaptation to in vivo and in vitro mass propagation. The objective of this study was to evaluate if an esta...

Background Sleeping sickness caused by Trypanosoma brucei (T.b.) gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was t...

Background: Trypanosoma (T.) evansi is a dyskinetoplastic variant of T. brucei that has gained the ability to be transmitted by all sorts of biting flies. T. evansi can be divided into type A, which is the most abundant and found in Africa, Asia and Latin America and type B, which has so far been isolated only from Kenyan dromedary camels. This st...

The Trypanosoma brucei repeat (TBR) is a tandem repeat sequence present on the Trypanozoon minichromosomes. Here, we report that the TBR sequence is not as homogenous as previously believed. BLAST analysis of the available T. brucei genomes reveals various TBR sequences of 177 bp and 176 bp in length, which can be sorted into two TBR groups based o...

Background Spliced Leader (SL) trypanosome RNA is detectable only in the presence of live trypanosomes, is abundant and the Trypanozoon subgenus has a unique sequence. As previously shown in blood from Guinean human African trypanosomiasis (HAT) patients, SL-RNA is an accurate target for diagnosis. Detection of SL-RNA in the cerebrospinal fluid (CS...

African trypanosomes are important parasites in sub-Saharan Africa that undergo a quorum-sensing dependent development to morphologically ‘stumpy forms’ in mammalian hosts to favour transmission by tsetse flies. However, some trypanosome clades have simplified their lifecycle by escaping dependence on tsetse allowing an expanded geographic range, w...

African trypanosomes are important parasites in sub-Saharan Africa that undergo a quorum-sensing dependent development to morphologically stumpy forms in mammalian hosts to favour disease transmission by tsetse flies ¹ . However, some trypanosome lineages have simplified their lifecycle by escaping dependence on tsetse allowing an expanded geograph...

Background Serological screening tests play a crucial role to diagnose gambiense human African trypanosomiasis (gHAT). Presently, they preselect individuals for microscopic confirmation, but in future “screen and treat” strategies they will identify individuals for treatment. Variability in reported specificities, the development of new rapid diagn...

Background:Serological screening tests play a crucial role to diagnose gambiense human African trypanosomiasis (gHAT). Presently, they preselect individuals for microscopic confirmation, but in future “screen and treat” strategies they will identify individuals for treatment. Variability in reported specificities, the development of new rapid diagn...

We report 4 cases of human African trypanosomiasis that occurred in Ethiopia in 2022, thirty years after the last previously reported case in the country. Two of 4 patients died before medicine became available. We identified the infecting parasite as Trypanosoma brucei rhodesiense. Those cases imply human African trypanosomiasis has reemerged.

We report 4 cases of human African trypanosomiasis that occurred in Ethiopia in 2022, thirty years after the last previously reported case in the country. Two of 4 patients died before medicine became available. We identified the infecting parasite as Trypanosoma brucei rhodesiense. Those cases imply human African trypanosomiasis has reemerged.

Rhodesiense human African trypanosomiasis is a lethal parasitic infection caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies in eastern and southern Africa. It accounts for around 5% of all cases of human African trypanosomiasis. Currently, there is no simple serological test for rhodesiense human African trypanosomiasis and d...

Having caused devastating epidemics during the 20th century, the incidence of life-threatening human African trypanosomiasis has fallen to historically low levels as a result of sustained and coordinated efforts over the past 20 years. Humans are the main reservoir of one of the two pathogenic trypanosome subspecies, Trypanosoma brucei gambiense, f...

Human African trypanosomiasis is a life-threatening parasitic infection transmitted by the tsetse fly in sub-Saharan Africa. The most common form is caused by Trypanosoma brucei gambiense, with humans as the main reservoir. Diagnosis in the field requires microscopic examination performed by specifically trained personnel. After over two decades of...

Human African trypanosomiasis is a life-threatening parasitic infection endemic to sub-Saharan Africa. Around 95% of cases are due to Trypanosoma brucei gambiense, found in western and central Africa. Clinical signs and symptoms are nonspecific, current diagnostic tests are not sufficiently accurate, and parasitological confirmation of infection re...

Background Detection of spliced leader (SL)-RNA allows sensitive diagnosis of gambiense human African trypanosomiasis (HAT). We investigated its diagnostic performance for treatment outcome assessment. Methods Blood and cerebrospinal fluid (CSF) from a consecutive series of 97 HAT patients, originating from the Democratic Republic of the Congo, we...

The World Health Organization targeted Trypanosoma brucei gambiense (Tbg) human African trypanosomiasis for elimination of transmission by 2030. Sensitive molecular markers that specifically detect Tbg type 1 (Tbg1) parasites will be important tools to assist in reaching this goal. We aim at improving molecular diagnosis of Tbg1 infections by targe...

The World Health Organization targeted Trypanosoma brucei gambiense (Tbg) human African trypanosomiasis for elimination of transmission by 2030. Sensitive molecular markers that specifically detect Tbg type 1 (Tbg1) parasites will be important tools to assist in reaching this goal. Here, we aim at improving molecular diagnosis of Tbg1 infections by...

Human African trypanosomiasis (HAT) is one of the neglected tropical diseases in sub-Saharan Africa. Early diagnosis and treatment prior to disease progression are crucial for the survival of HAT patients. We had previously established a loop-mediated isothermal amplification (LAMP) method for HAT diagnosis in which the reagents were dried for fiel...

Trypanosoma evansi (T. evansi) is a flagellated parasite with worldwide distribution, mainly affecting camels, horses, dogs, buffaloes and wild animals. Trypanosomosis caused by T. evansi, known as surra, is a vector borne disease that affects the health and productivity of camels. The aim of our study was to assess the prevalence of trypanosomosis...

Background: The World Health Organization targeted Trypanosoma brucei gambiense human African trypanosomiasis (gHAT) for elimination as a public health problem and for elimination of transmission. To measure gHAT elimination success with prevalences close to zero, highly specific diagnostics are necessary. Such a test exists in the form of an anti...

Trypanosoma evansi (T. evansi) is a hemoflagellate parasite that affects a broad range of mammalian hosts and that causes a disease called surra. Diagnosis of surra based on clinical symptoms alone is inaccurate. Therefore, a variety of serological and molecular diagnostic tests are used to assist in the detection of T. evansi infections. The aim o...

Trypanosoma evansi is a protozoon parasite with worldwide distribution affecting many animal species. This parasite causes surra, characterised by anaemia, icterus, abortion and immunosuppression, which makes it a real threat to animal health. In Algeria, there is little information about the prevalence of T. evansi . The objective of this study wa...

Background: Kinesin-related gene diversity among strains and species of Leishmania may impact the sensitivity and specificity of serodiagnostic tests for visceral leishmaniasis (VL). Methods: In this study, we report on the recombinant expression of this novel Iranian Leishmania infantum (MCAN14/47) homologue of rK39 (Li-rK39), in L. tarentolae....

Equine trypanosomosis is a complex of infectious diseases called dourine, nagana and surra. It is caused by several species of the genus Trypanosoma that are transmitted cyclically by tsetse flies, mechanically by other haematophagous flies, or sexually. Trypanosoma congolense (subgenus Nannomonas) and T. vivax (subgenus Dutonella) are genetically...

Background Trypanosoma evansi is mechanically transmitted by biting flies and affects camels, equines, and other domestic and wild animals in which it causes a disease called surra. At least two types of Trypanosoma evansi circulate in Ethiopia: type A, which is present in Africa, Latin America and Asia, and type B, which is prevalent in Eastern Af...

Details on the outcome of mice infected with different T. evansi stocks and treated with different drugs. ISM = isometamidium chloride hydrochloride, DIM = diminazene diaceturate, DIM-SEQ = diminazene diaceturate and phenazone granules, MelCy = melarsamine hydrochloride, HOM = homidium chloride. D = death, N = no parasites detected in blood, P = pa...

Physicochemical test result of the used batch of Veridium. (PDF)

Physicochemical test result of the used batch of Bovidium. (PDF)

Physicochemical test result of the used batch of Veriben. (PDF)

Physicochemical test result of the used batch of Sequzene. (PDF)

Highlights gambiense-HAT is targeted for elimination with zero transmission in humans. Innovative tools may contribute to the achievement of elimination; these tools include rapid diagnostic tests, improved tsetse-control tools, and an oral drug to treat both stages of disease. Research is revealing associations between infection outcome, including...

The primate-specific serum protein apolipoprotein L1 (APOL1) is the only secreted member of a family of cell death promoting proteins (1-4) . APOL1 kills the bloodstream parasite Trypanosoma brucei brucei, but not the human sleeping sickness agents T.b. rhodesiense and T.b. gambiense (3) . We considered the possibility that intracellular members of...

Trypanosomes cause a variety of diseases in man and domestic animals in Africa, Latin America and Asia. In the Trypanozoon subgenus, Trypanosoma brucei gambiense and T. b. rhodesiense cause human African trypanosomiasis, while T. b. brucei, T. evansi and T. equiperdum are responsible for nagana, surra and dourine in domestic animals, respectively....

Trypanosoma equiperdum is the causative agent of dourine, a sexually-transmitted infection of horses. This parasite belongs to the subgenus Trypanozoon that also includes the agent of sleeping sickness (Trypanosoma brucei) and surra (Trypanosoma evansi). We herein report the genome sequence of a T. equiperdum strain OVI, isolated from a horse in So...

Tsetse flies are the sole vectors of Trypanosoma brucei parasites that cause sleeping sickness. Our knowledge on the early interface between the infective metacyclic forms and the mammalian host skin is currently highly limited. Glossina morsitans flies infected with fluorescently tagged T. brucei parasites were used in this study to initiate natur...

Transmissibility of different T.b.brucei strains in G.m.morsitans tsetse flies. Teneral male tsetse flies were infected with T.b.brucei AnTAR1, AnTat1.1EdsRed or AnTat1.1ETagGFP2 in the presence of 10 mM reduced L-glutathion. Parasite infection in the salivary gland was evaluated by induced probing on pre-warmed microscopy slides. Indicated are the...

Parasite persistence at a late infection time point. Flow cytometry profiles of control mice and mice at 18 dpi following natural infection with two differentially labeled parasite strains (AnTat1.1EdsRed or AnTat1.1ETagGFP2). Mice were exposed to the bites of infected tsetse flies to introduce AnTat1.1EdsRed parasites in the left ear and AnTat1.1E...

Parasite viability in the inoculum. The viability of the DEAE52-purified MCF and BSF parasites was assessed by 7AAD-based staining and flow cytometry analysis in (A) the parasite inoculum and (B) the inoculum approximately 3h after preparation. Percentage viable trypanosomes are indicated in the dot plots. The parasites in this viability analysis c...

Feeding response of flies in function of increasing temperature. Feeding response of 3-day starved flies on an artificial horse blood meal through a silicone membrane. Membrane surface temperatures were set to match the average left infected ear and the right uninfected ear temperatures measured at 8 dpi (25.1°C and 24.0°C respectively) and at a hi...

Parasite retention and proliferation at the dermal infection initiation site. Flow cytometry profiles illustrating the detection of (A) AnTat1.1EdsRed or (B) AnTat1.1ETagGFP2 trypanosomes in the infection initiation site (L ear) and absence in the contralateral side (R ear). Shown events are all singlets in the ear dermal extracts at 90 hpi. These...

Parasite movement inside the dermis. Movement of T.b.brucei AnTat1.1EdsRed parasites recorded by confocal microscopy inside the ear dermal sheets at 90 hpi. Parasites display a typical anterior-posterior movement consistent with a physical constraint inside the dermis. (AVI)

Trypanozoon parasites infect both humans, causing sleeping sickness, and animals, causing nagana, surra, and dourine. Control of the nagana and surra depends to a great extent on chemotherapy. However, drug resistance to several of the front-line drugs is rising. Furthermore, there is no official treatment for dourine. Therefore, there is an urgent...

Raw images of the Western blot strips with their corresponding experiments and the final cropped image included in the corrected Fig 4. The raw uncropped image was taken with a Panasonic DMC-FZ50 digital camera. The relationship between the strip numbers, the experiments and the original pictures is listed in the table. The two Western blot strips...

[This corrects the article DOI: 10.1371/journal.pntd.0000509.].

Animal trypanosomosis caused by Trypanosoma vivax (T. vivax) is a devastating disease causing serious economic losses. Most molecular diagnostics for T. vivax infection target the ribosomal DNA locus (rDNA) but are challenged by the heterogeneity among T. vivax strains. In this study, we investigated the rDNA heterogeneity of Ethiopian T. vivax str...

Appendix S1. Candidate genes.

Table S1. Proportion of heterozygous SNPs in patient pairs. Table S2. List of SNPs that differentiate BT and AT strains. Table S3. List of SNPs that differentiate cured and relapsing strains.

Figure S1. Cluster identification. Figure S2. Cluster analysis of Tbg isolates. Figure S3. SNP Heterozygosity. Figure S4. False discovery rate of SNPs distinguishing patient Pairs. Figure S5. Significant SNPs Identified by DAPC.

The trypanosome Trypanosoma brucei gambiense (Tbg) is a cause of human African trypanosomiasis (HAT) endemic to many parts of sub-Saharan Africa. The disease is almost invariably fatal if untreated and there is no vaccine, which makes monitoring and managing drug resistance highly relevant. A recent study of HAT cases from the Democratic Republic o...

Dendritic cells (DCs) are a subset of leukocytes highly specialized in antigen-presentation to T cells, thus promoting the immune response. DCs occur in the meninges and choroid plexus. Brain DCs and brain-derived antigens are drained by cerebrospinal fluid in the afferent lymphatic vessels of cervical lymph nodes (cLNs) for antigen presentation. I...

Human African trypanosomosis (HAT) in the Democratic Republic of the Congo (DRC) is caused by the protozoan Trypanosoma brucei gambiense. Until recently, all patients in the second or neurological stage of the disease were treated with melarsoprol. At the end of the past and the beginning of the present century, alarmingly high relapse rates in pat...

Genetic engineering with luciferase reporter genes allows monitoring Trypanosoma brucei (T.b.) infections in mice by in vivo bioluminescence imaging (BLI). Until recently, luminescent T.b. models were based on Renilla luciferase (RLuc) activity. Our study aimed at evaluating red-shifted luciferases for in vivo BLI in a set of diverse T.b. strains o...

Human African trypanosomiasis (HAT), also known as sleeping sickness, is caused by two subspecies of the parasite Trypanosoma brucei (T.b.) and is transmitted by the tsetse fly (Glossina spss) in sub-Saharan Africa. T.b. rhodesiense causes an acute form of sleeping sickness in East-Africa and primarily affects farmers, game park rangers and tourist...

Animal African trypanosomoses (AAT) are caused by flagellated protozoa of the Trypanosoma genus and contribute to considerable losses in animal production in Africa, Latin America and South East Asia. Trypanosoma congolense is considered the economically most important species. Drug resistant T. congolense strains present a threat to the control of...

New compounds for the treatment of human African trypanosomiasis (HAT) are urgently required. Trypanosoma brucei (T.b.) gambiense is the leading cause of HAT, yet T.b. gambiense is often not the prime target organism in drug discovery. This may be attributed to the difficulties in handling this subspecies and the lack of an efficient viability assa...

List of strains isolated from cured and relapsing patients and their characteristics. (DOC)

Sleeping sickness due to Trypanosoma brucei (T.b.) gambiense is still a major public health problem in some central African countries. Historically, relapse rates around 5% have been observed for treatment with melarsoprol, widely used to treat second stage patients. Later, relapse rates of up to 50% have been recorded in some isolated foci in Ango...

Sequencing primers list (0.06 MB DOC)

Spanish translation of the abstract by MER. (0.04 MB DOC)

The depolarization of mitochondrial membrane in T.b. brucei incubated with 1 µM cordycepin was measured by incubating T. brucei with TMRE. (0.59 MB PPT)

Supplementary methods. (0.03 MB DOC)

Translation of the Abstract into French by Philippe Büscher (0.03 MB DOC)

Translation of the Abstract into Spanish by Martin Rottenberg (0.03 MB DOC)

Monitoring Trypanosoma spread using real-time imaging in vivo provides a fast method to evaluate parasite distribution especially in immunoprivileged locations. Here, we generated monomorphic and pleomorphic recombinant Trypanosoma brucei expressing the Renilla luciferase. In vitro luciferase activity measurements confirmed the uptake of the coelen...