Toxoplasmosis prevalence in cats of Kingabwa and Limete résidentiel districts in Kinshasa

During seven months, 150 fecal samples were collected in cats of Kingabwa and residential Limete in Kinshasa. Coprological analysis by quantitative flotation gave a crude prevalence of 14.5 %, with 20 % prevalence at Kingabwa and 8.6 % for residential Limete in terms of neighborhoods (p<0.05), 13.3 % for males and 16 % for females (p<0,05) and 16 % of cats aged one year or more and 13.3 % in those with less than a year (p<0,05). Cats play an important role in the high prevalence of human toxoplasmosis observed in Kinshasa. Veterinarians should integrate, in addition to deworming, the administration of pyriméthamine and sulfadiazine at the time of anti-rabies vaccination of cats in order to fight against feline toxoplasmosis

Nearly complete genome sequences of eight rabies virus strains obtained from domestic carnivores in the Democratic Republic of the Congo

In this report, we describe eight nearly complete genome sequences of rabies virus strains collected in the Democratic Republic of the Congo from domestic carnivores in 2017 and 2018. All of them clustered into a specific phylogroup among the Africa 1b lineage in the Cosmopolitan clade

Toxoplasmosis prevalence in cats of Kingabwa and Limete résidentiel districts in Kinshasa

Durant sept mois, 150 échantillons de selles ont été collectés chez les chats des quartiers Kingabwa et Limete résidentiel à Kinshasa. Les analyses coprologiques par flottaison quantitative ont donné une prévalence brute de toxoplasmose de 14,7 %, à raison de 20 % à Kingabwa et de 8,6 % à Limete résidentiel pour ce qui est des quartiers (p? 0,05), de 13,3 % chez les mâles et de 16 % chez les femelles (p?0,05) concernant le sexe et de 16 % chez les chats âgés d’une année et plus et de 13,3 % chez ceux ayant moins d’une année (p?0,05) pour ce qui est de l’âge. Les chats joueraient un rôle important dans la forte prévalence de la toxoplasmose humaine observée à Kinshasa. Les médecins vétérinaires devront intégrer en plus du vermifugeage, l’administration de la pyriméthamine et de la sulfadiazine lors de la vaccination antirabique chez les chats afin de lutter contre la toxoplasmose féline. Mots-clés: Prévalence, Toxoplasmose, chats, Kingabwa, Limete résidentiel, Kinshasa.During seven months, 150 fecal samples were collected in cats of Kingabwa and residential Limete in Kinshasa. Coprological analysis by quantitative flotation gave a crude prevalence of 14.5 %, with 20 % prevalence at Kingabwa and 8.6 % for residential Limete in terms of neighborhoods (p?0.05), 13.3 % for males and 16 % for females (p?0,05) and 16 % of cats aged one year or more and 13.3 % in those with less than a year (p?0,05). Cats play an important role in the high prevalence of human toxoplasmosis observed in Kinshasa. Veterinarians should integrate, in addition to deworming, the administration of pyriméthamine and sulfadiazine at the time of anti-rabies vaccination of cats in order to fight against feline toxoplasmosis. Keywords: Prevalence, Toxoplasmosis, cats, Kingabwa, Limete residential, Kinshasa

Etude observationnelle sur l’hémovigilance transfusionnelle à Kinshasa, République Démocratique du Congo: Haemovigilance in blood transfusion: an observational study from Kinshasa, the Democratic Republic of the Congo

Context and objective. Although most countries in sub-Saharan Africa have transfusion centers, haemovigilance data are paradoxically scarce. The objective of the present study was to identify the recipient adverse effect (RAT) of blood transfusion. Methods. We conducted a cross-sectional observational study in two blood transfusion centers in Kinshasa, between July and November 2015. The general principles of haemovigilance during the transfusion episode were observed to identify the EIR. On each blood product, bacteriological, immunological, serological and parasitic analyzes were systematically performed. Results. 346 subjects were enrolled (female, 53.2%).The overall frequency of RAT during transfusion was 2.9%. It was most commonly urticaria (5 cases), pruritus (4 cases), fever (3 cases) and vomiting (3 cases). Control tests on patients with RAT yielded the following results: 2 seropositive for Human Immunodeficiency Virus (HIV), 2 seropositive for Hepatitis C virus (HVC), and 1 seropositive for Rapid Plasma Reagent (RPR) test. Conclusion. RAT is relatively common in Kinshasa due partially to compatibility error. The observance of the protocols of haemovigilance system is not optimal in both hospitals studied. A large multicenter study should be performed to better identify the concerns and thus secure blood products. Contexte et objectif. Bien que la plupart de pays d’Afrique subsaharienne aient de centres transfusionnels, mais les données sur l’hémovigilance sont paradoxalement fragmentaires. L’objectif de la présente étude était d’identifier l’effet indésirable du receveur (EIR) transfusionnel. Méthodes. Nous avons réalisé une étude observationnelle transversale dans deux centres de transfusion sanguine à Kinshasa, entre juillet et novembre 2015.Les principes généraux de l’hémovigilance au cours de l’épisode transfusionnel ont été observés en vue d’identifier l’EIR. Pour tout cas d’EIR, le contrôle du groupe sanguin, des analyses bactériologique, immunologique (test de compatibilité), sérologique et parasitaire ont été systématiquement effectués dans la poche du produit sanguin labile (PSL) et du receveur. Résultats.346 sujets ont été enrôlés (sexe féminin, 53,2%).La fréquence globale d’EIR durant la transfusion a été de 2,9%.Il s’agissait de l’urticaire (5 cas), d’un prurit (4 cas), de la fièvre (3 cas) et de vomissements (3 cas). Alors qu’en milieu alcalin, tous les tests étaient compatibles, deux cas d’incompatibilités ont été observés à la fois en milieu albumineux et de Coombs. Après contrôle de qualité des cas ayant présenté l’EIR, 5 PSL de donneurs se sont révélés positifs (HIV, 2 cas ; HVC, 2 cas et rapid plasma reagen test, RPR, 1 cas). Conclusion. L’EIR est relativement fréquente à Kinshasa due en partie par une erreur de compatibilité. L’observance des protocoles du système de l’hémovigilance n’est pas optimale dans les deux formations étudiées. Une étude multicentrique à grande échelle est à envisager pour mieux identifier les écueils de l’hémovigilance et ainsi sécuriser les PSL

Isolation of Trypanosoma brucei gambiense from Cured and Relapsed Sleeping Sickness Patients and Adaptation to Laboratory Mice

Human African trypanosomiasis, or sleeping sickness, is still a major public health problem in central Africa. Melarsoprol is widely used for treatment of patients where the parasite has already reached the brain. In some regions in Angola, Sudan, Uganda and Democratic Republic of the Congo, up to half of the patients cannot be cured with melarsoprol. From previous investigations it is not yet clear what causes these high relapse rates. Therefore we aimed to establish a parasite collection isolated from cured as well as relapsed patients for downstream comparative drug sensitivity profiling. From 360 sleeping sickness patients, blood and cerebrospinal fluid (CSF) was collected before treatment and along the prescribed 24 months follow-up. Blood and CSF were inoculated in thicket rats (Grammomys surdaster), Natal multimammate mice (Mastomys natalensis) and immunodeficient laboratory mice (Mus musculus). Thus, we established a unique collection of Trypanosoma brucei gambiense type I parasites, isolated in the same disease focus and within a limited period, including 12 matched strains isolated from the same patient before treatment and after relapse. This collection is now available for genotypic and phenotypic characterisation to investigate the mechanism behind abnormally high treatment failure rates in Mbuji-Mayi, Democratic Republic of the Congo

Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity

Aquaglyceroporins (AQPs) transport water and glycerol and play important roles in drug-uptake in pathogenic trypanosomatids. For example, AQP2 in the human-infectious African trypanosome, Trypanosoma brucei gambiense, is responsible for melarsoprol and pentamidine-uptake, and melarsoprol treatment-failure has been found to be due to AQP2-defects in these parasites. To further probe the roles of these transporters, we assembled a T. b. brucei strain lacking all three AQP-genes. Triple-null aqp1-2-3 T. b. brucei displayed only a very moderate growth defect in vitro, established infections in mice and recovered effectively from hypotonic-shock. The aqp1-2-3 trypanosomes did, however, display glycerol uptake and efflux defects. They failed to accumulate glycerol or to utilise glycerol as a carbon-source and displayed increased sensitivity to salicylhydroxamic acid (SHAM), octyl gallate or propyl gallate; these inhibitors of trypanosome alternative oxidase (TAO) can increase intracellular glycerol to toxic levels. Notably, disruption of AQP2 alone generated cells with glycerol transport defects. Consistent with these findings, AQP2-defective, melarsoprol-resistant clinical isolates were sensitive to the TAO inhibitors, SHAM, propyl gallate and ascofuranone, relative to melarsoprol-sensitive reference strains. We conclude that African trypanosome AQPs are dispensable for viability and osmoregulation but they make important contributions to drug-uptake, glycerol-transport and respiratory-inhibitor sensitivity. We also discuss how the AQP-dependent inverse sensitivity to melarsoprol and respiratory inhibitors described here might be exploited

Comparative genomics of drug resistance in <i>Trypanosoma brucei rhodesiense</i>

Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol-pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu(131) in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine

Instability of aquaglyceroporin (Aqp) 2 contributes to drug resistance in trypanosoma brucei

Defining mode of action is vital for both developing new drugs and predicting potential resistance mechanisms. Sensitivity of African trypanosomes to pentamidine and melarsoprol is predominantly mediated by aquaglyceroporin 2 (TbAQP2), a channel associated with water/glycerol transport. TbAQP2 is expressed at the flagellar pocket membrane and chimerisation with TbAQP3 renders parasites resistant to both drugs. Two models for how TbAQP2 mediates pentamidine sensitivity have emerged; that TbAQP2 mediates pentamidine translocation across the plasma membrane or via binding to TbAQP2, with subsequent endocytosis and presumably transport across the endosomal/lysosomal membrane, but as trafficking and regulation of TbAQPs is uncharacterised this remains unresolved. We demonstrate that TbAQP2 is organised as a high order complex, is ubiquitylated and is transported to the lysosome. Unexpectedly, mutation of potential ubiquitin conjugation sites, i.e. cytoplasmic-oriented lysine residues, reduced folding and tetramerization efficiency and triggered ER retention. Moreover, TbAQP2/TbAQP3 chimerisation, as observed in pentamidine-resistant parasites, also leads to impaired oligomerisation, mislocalisation and increased turnover. These data suggest that TbAQP2 stability is highly sensitive to mutation and that instability contributes towards the emergence of drug resistance

Drug Resistance in Eukaryotic Microorganisms

Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies

Trypanosoma brucei gambiense: HMI-9 medium containing methylcellulose and human serum supports the continuous axenic in vitro propagation of the bloodstream form

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 established method for axenic culture of pleomorphic bloodstream form T.b. brucei strains, based on methylcellulose containing HMI-9 medium, also facilitated the continuous in vitro propagation of other bloodstream form Trypanozoon strains, in particular of T.b. gambiense. Bloodstream form trypanosomes from one T.b. brucei, two T.b. rhodesiense, one T. evansi and seven T.b. gambiense strains were isolated from mouse blood and each was concurrently cultivated in liquid and methylcellulose-containing HMI-9 based medium, either with or without additional human serum supplementation, for over 10 consecutive sub passages. Although HMI-9 based medium supplemented with 1.1% (w/v) methylcellulose supported the continuous cultivation of all non-gambiense strains better than liquid media could, the in vitro cultivation of all gambiense strains was only achieved in HMI-9 based medium containing 1.1% (w/v) methylcellulose, 15% (v/v) fetal calf serum and 5% (v/v) heat-inactivated human serum