RESUMO
Sibert and Rubin (Reports, 4 June 2021, p. 1105) claim to have identified a previously unidentified, major extinction event of open-ocean sharks in the early Miocene. We argue that their interpretations are based on an experimental design that does not account for a considerable rise in the sedimentation rate coinciding with the proposed event, nor for intraspecific variation in denticle morphology.
Assuntos
Tubarões , AnimaisRESUMO
Enameloid, the hyper-mineralized tissue covering shark teeth is a complex structure resulting from both ameloblast and odontoblast activity. The way these two types of cells interact to set up this tissue is not fully understood and results in the formation of subunits in the enameloid: the Single Crystallite Enameloid (SCE) and the Bundled Crystallite Enameloid (BCE). Using the Focused Ion Beam Nanotomography (FIB-nt), 3D images were produced to assess the relationship between the SCE and BCE of one fossil and one recent neoselachian shark teeth. 3D analysis of crystallite bundles reveals a strong connection between the crystallites forming the SCE and those forming the bundles of the Radial Bundle Enameloid (RBE), a component of the BCE, although it has been suggested that SCE and BCE have a different origin: epithelial for the SCE and mesenchymal for the BCE. Another significant result of the use of FIB-nt is the visualization of frequent branching among the radial bundles forming the RBE, including horizontal link between adjacent bundles. FIB-nt demonstrates therefore a strong potential to decipher the complex evolution of hyper-mineralised tissue in shark teeth, and, therefore, to better understand the evolution of tooth structure among basal Gnathostomes.
Assuntos
Minerais/química , Animais , Evolução Biológica , Fósseis , Microscopia Eletrônica de Varredura , Tubarões/anatomia & histologia , Dente/anatomia & histologiaRESUMO
This survey screened native dogs (Canis familiaris) in Gabon (Africa) for trypanosome infection. A total of 376 apparently healthy dogs, divided into two populations, were examined. The first group included 252 semi-domesticated dogs inhabiting 16 villages of the Ogooué-Ivindo Province, a rural inland area in northeast Gabon, and the second group 124 dogs belonging to protection companies or families from Libreville (n = 113) and Port-Gentil (n = 11), in the coastal area of Gabon. Both study areas include active or former foci of sleeping sickness in Gabon. Molecular testing (polymerase chain reaction) was performed on blood samples from dogs in both groups. All dogs were negative for T. congolense ("savanna type" and "forest type"). Eighteen dogs (4.7%), however, tested positive for T. brucei s.l.: 3% (8/252) were from the Ogooué-Ivindo Province, and 8% (10/124) from the coastal area. These animals may be potential reservoirs of the parasite T. brucei gambiense, responsible for human African trypanosomiasis. This hypothesis, as well as the role of the dog as a sentinel of human infection by T. brucei gambiense, should be investigated in further studies.
Assuntos
Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Tripanossomíase Africana/veterinária , Animais , Cães , Gabão/epidemiologia , Inquéritos Epidemiológicos , Tripanossomíase Africana/epidemiologiaRESUMO
In order to better understand the epidemiology of Human and Animal trypanosomiasis that occur together in sleeping sickness foci, a study of prevalences of animal parasites (Trypanosoma vivax, T. congolense "forest type", and T. simiae) infections was conducted on domestic animals to complete the previous work carried on T. brucei gambiense prevalence using the same animal sample. 875 domestic animals, including 307 pigs, 264 goats, 267 sheep and 37 dogs were sampled in the sleeping sickness foci of Bipindi, Campo, Doumé and Fontem in Cameroon. The polymerase chain reaction (PCR) based method was used to identify these trypanosome species. A total of 237 (27.08%) domestic animals were infected by at least one trypanosome species. The prevalence of T. vivax, T. congolense "forest type" and T. simiae were 20.91%, 11.42% and 0.34% respectively. The prevalences of 7 vivax and T. congolense "forest type" differed significantly between the animal species and between the foci (p < 0.0001); however, these two trypanosomes were found in all animal species as well as in all the foci subjected to the study. The high prevalences of 7 vivax and T congolense "forest type" in Bipindi and Fontem-Center indicate their intense transmission in these foci.
Assuntos
Animais Domésticos/parasitologia , Trypanosoma congolense/isolamento & purificação , Trypanosoma vivax/isolamento & purificação , Tripanossomíase Africana/veterinária , Animais , Camarões/epidemiologia , DNA de Protozoário/isolamento & purificação , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Eletroforese em Gel de Ágar , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Doenças das Cabras/transmissão , Cabras , Humanos , Prevalência , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/transmissão , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Doenças dos Suínos/transmissão , Árvores , Trypanosoma/classificação , Trypanosoma/genética , Trypanosoma/isolamento & purificação , Trypanosoma congolense/genética , Trypanosoma vivax/genética , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/transmissãoRESUMO
A new index for the risk for transmission of human African trypanosomiasis was developed from an earlier index by adding terms for the proportion of tsetse infected with Trypanosoma brucei gambiense group 1 and the contribution of animals to tsetse diet. The validity of the new index was then assessed in the Fontem focus of southwest Cameroon. Averages of 0.66 and 4.85 Glossina palpalis palpalis (Diptera: Glossinidae) were caught per trap/day at the end of one rainy season (November) and the start of the next (April), respectively. Of 1596 tsetse flies examined, 4.7% were positive for Trypanosoma brucei s.l. midgut infections and 0.6% for T. b. gambiense group 1. Among 184 bloodmeals identified, 55.1% were from pigs, 25.2% from humans, 17.6% from wild animals and 1.2% from goats. Of the meals taken from humans, 81.5% were taken at sites distant from pigsties. At the end of the rainy season, catches were low and similar between biotopes distant from and close to pigsties, but the risk for transmission was greatest at sites distant from the sties, suggesting that the presence of pigs reduced the risk to humans. At the beginning of the rainy season, catches of tsetse and risk for transmission were greatest close to the sties. In all seasons, there was a strong correlation between the old and new indices, suggesting that both can be used to estimate the level of transmission, but as the new index is the more comprehensive, it may be more accurate.
Assuntos
Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/parasitologia , Animais , Camarões/epidemiologia , DNA de Protozoário/genética , Comportamento Alimentar , Humanos , Fatores de Risco , Estações do Ano , Suínos/sangue , Trypanosoma brucei gambiense/genética , Trypanosoma brucei gambiense/isolamento & purificação , Tripanossomíase Africana/epidemiologia , Moscas Tsé-Tsé/fisiologiaRESUMO
An explanation of the endemic nature and/or the resurgence of Human African Trypanosomiasis (HAT) in the historic foci in West and Central Africa may be the existence of an animal reservoir. In some HAT foci, pigs were found infected by Trypanosoma brucei gambiense but the implication of the other domestic animals was not quite evaluated. This study aims to determine the prevalence of T. b. gambiense in domestic animal species (goat, sheep, pig and dog) commonly found in the four active HAT foci in Cameroon (Bipindi, Fontem, Campo and Doumé). Blood samples were collected from 307 pigs, 264 goats, 267 sheep and 37 dogs and used for parasitological (QBC), immunological (LiTat 1.3 CATT) and molecular (PCR) analyses. QBC detected trypanosomes in 3.88% domestic animals while 22.7% were sero-positive with LiTat 1.3 CATT tests. Of the 875 animals analysed, 174 (19.88%) harboured T. brucei s.l. DNA, found in each of the four types of animal and in the four localities. The infection rate significantly differed among the animal species (p < 0.0001) and localities (p < 0.0001). The PCR also revealed T. b. gambiense group 1 DNA in 27 (3.08 %) domestic animals. The specific infection rates were as follows: sheep (6.74%), goats (3.08%), pigs (0.32%) and dogs (O%). T. b. gambiense was found in 8 (3.92%) animals from Bipindi, 15 (4.83%) from Campo, 4 (2.59%) from FontemCenter and none from Doumé. The infection rates significantly differed between the localities, and correlated with the intensity of HAT transmission in the foci.
Assuntos
Animais Domésticos/parasitologia , Reservatórios de Doenças , Trypanosoma brucei brucei/isolamento & purificação , Tripanossomíase Africana/parasitologia , Animais , Camarões/epidemiologia , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Cães , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Cabras , Humanos , Reação em Cadeia da Polimerase/métodos , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Trypanosoma brucei brucei/genética , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/veterináriaRESUMO
We report the isolation of a novel bacterium, strain C1(T), from the midgut of the tsetse fly Glossina palpalis gambiensis, one of the vector insects responsible for transmission of the trypanosomes that cause sleeping sickness in sub-Saharan African countries. Strain C1(T) is a motile, facultatively anaerobic, rod-like bacterium (0.8-1.0 microm in diameter; 2-6 microm long) that grows as single cells or in chains. Optimum growth occurred at 25-35 degrees C, at pH 6.7-8.4 and in medium containing 5-20 g NaCl l(-1). The bacterium hydrolysed urea and used L-lysine, L-ornithine, citrate, pyruvate, D-glucose, D-mannitol, inositol, D-sorbitol, melibiose, amygdalin, L-arabinose, arbutin, aesculin, D-fructose, D-galactose, glycerol, maltose, D-mannose, raffinose, trehalose and d-xylose; it produced acetoin, reduced nitrate to nitrite and was positive for beta-galactosidase and catalase. The DNA G+C content was 53.6 mol%. It was related phylogenetically to members of the genus Serratia, family Enterobacteriaceae, the type strain of Serratia fonticola being its closest relative (99 % similarity between 16S rRNA gene sequences). However, DNA-DNA relatedness between strain C1(T) and S. fonticola DSM 4576(T) was only 37.15 %. Therefore, on the basis of morphological, nutritional, physiological and fatty acid analysis and genetic criteria, strain C1(T) is proposed to be assigned to a novel Serratia species, Serratia glossinae sp. nov. (type strain C1(T) =DSM 22080(T) =CCUG 57457(T)).
Assuntos
Serratia/isolamento & purificação , Moscas Tsé-Tsé/microbiologia , Animais , Bactérias Anaeróbias/isolamento & purificação , Composição de Bases/genética , Burkina Faso , Catalase/metabolismo , Primers do DNA , DNA Bacteriano/química , DNA Bacteriano/genética , Intestinos/microbiologia , Dados de Sequência Molecular , Nitratos/metabolismo , Filogenia , Reação em Cadeia da Polimerase , Pupa/microbiologia , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Serratia/classificação , Serratia/genética , Serratia/metabolismo , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/patogenicidade , Ureia/metabolismoRESUMO
Kinases, which number > 500 in humans, are a class of enzymes that participate in an array of important functions within normal cellular physiology and during various pathological conditions. Due to the key role of kinases in the regulation of all aspects of cellular signaling and the well established contribution of kinase dysregulation to the etiology of many human pathologies, the development of kinase inhibitors has emerged as a therapeutic strategy for the treatment of human disease, including most notably oncology. Difficulties generating selective inhibitors have hampered their use in other therapeutic areas with less tolerance for off-target effects. However, with an increasing understanding of kinase structures and with the advent of newer inhibitor design strategies more highly selective inhibitors are beginning to emerge. This has prompted interest in utilizing kinase inhibitors in therapeutic areas beyond oncology, including acute and chronic neurodegenerative conditions for which disease modify therapies are lacking. This review provides a background in acute (i.e. brain ischemia and traumatic brain injury) and chronic (i.e. Alzheimer's, Parkinson's, Huntington's disease, amyotrophic lateral sclerosis and multiple sclerosis) neurodegenerative conditions. Then, the role of several kinase (i.e. JNK3, p38 MAPK, ERK, PKC, ROCKII, GSK3, Cdk5, MLK, EphB3 kinase, RIP1 kinase, LRRK2, TTBK1, ASK1, CK, DAPK, and PKN1) that could serve as potential therapeutic targets for these maladies are reviewed.
Assuntos
Doenças Neurodegenerativas/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Fosfotransferases/antagonistas & inibidores , Humanos , Fármacos Neuroprotetores/químicaRESUMO
Substantial differences have been observed between the cyclical transmission of three Trypanosoma brucei gambiense field isolates in Glossina palpalis gambiensis (Ravel et al., 2006). Differences in the pleomorphism of these isolates in rodent used to provide the infective feed to Glossina, could explain such results, since stumpy forms are preadapted for differentiation to procyclic forms when taken up in a tsetse bloodmeal. To assess this possibility, mice were immunosuppressed and inoculated intraperitoneally with the three isolates (six mice for each trypanosome isolate); then parasitaemia and pleomorphism were determined daily for each mouse. The three T. b. gambiense isolates induced different infection patterns in mouse. The parasitaemia peak was rapidly reached for all the isolates and maintained until mice death for two isolates, while the third isolate rapidly showed a falling phase followed by a second parasitaemia plateau. The proportion of the stumpy forms varied from 15% to 70% over the duration of the experiment and according to the isolate. One isolate, which displayed the highest proportion of stumpy forms and reached the stumpy peak at the onset of the falling phase of parasitaemia, was used to study the relationship between the proportion of stumpy forms and transmissibility to tsetse fly. The results indicated that the transmissibility of trypanosomes was not correlated to the proportion of non-dividing stumpy forms.
Assuntos
Estágios do Ciclo de Vida , Trypanosoma brucei gambiense/crescimento & desenvolvimento , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/parasitologia , Animais , Interações Hospedeiro-Parasita , Humanos , Insetos Vetores/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Parasitemia/parasitologia , Trypanosoma brucei gambiense/isolamento & purificação , Tripanossomíase Africana/parasitologiaRESUMO
Breeding indigenous African taurine cattle tolerant to trypanosomosis is a straightforward approach to control costs generated by this disease. A recent study identified quantitative trait loci (QTL) underlying trypanotolerance traits in experimental crosses between tolerant N'Dama and susceptible Boran zebu cattle. As trypanotolerance is thought to result from local adaptation of indigenous cattle breeds, we propose an alternative and complementary approach to study the genetic architecture of this trait, based on the identification of selection signatures within QTL or candidate genes. A panel of 92 microsatellite markers was genotyped on 509 cattle belonging to four West African trypanotolerant taurine breeds and 10 trypanosusceptible European or African cattle breeds. Some of these markers were located within previously identified QTL regions or candidate genes, while others were chosen in regions assumed to be neutral. A detailed analysis of the genetic structure of these different breeds was carried out to confirm a priori grouping of populations based on previous data. Tests based on the comparison of the observed heterozygosities and variances in microsatellite allelic size among trypanotolerant and trypanosusceptible breeds led to the identification of two significantly less variable microsatellite markers. BM4440, one of these two outlier loci, is located within the confidence interval of a previously described QTL underlying a trypanotolerance-related trait. Detection of selection signatures appears to be a straightforward approach for unravelling the molecular determinism of trypanosomosis pathogenesis. We expect that a whole genome approach will help confirm these results and achieve a higher resolving power.
Assuntos
Doenças dos Bovinos/genética , Bovinos/genética , Locos de Características Quantitativas , Tripanossomíase Africana/veterinária , Alelos , Animais , Teorema de Bayes , Cruzamento , Bovinos/imunologia , Doenças dos Bovinos/imunologia , Análise por Conglomerados , Variação Genética , Genética Populacional , Genótipo , Imunidade Inata , Repetições de Microssatélites , Análise de Sequência de DNA , Tripanossomíase Africana/genética , Tripanossomíase Africana/imunologiaRESUMO
Following confirmed cases of trypanosomosis in military working dogs, a cross-sectional study was undertaken to evaluate the source of infection and determine the prevalence of canine infection with Trypanosoma congolense in the urban focus of Abidjan, Ivory Coast. Blood from 123 dogs were collected and subjected to PCR using specific primers for Trypanosoma congolense "forest type". In addition, an entomological study was conducted in an urban area near the forest surronding the military camp. The observed prevalence was 30.1% and PCR positivity to Trypanosoma congolense was not significantly associated with sex or age of animals. This study demonstrates the high contamination rate of dogs in enzootic zones, the potential risk of introduction of the disease in free animal populations and the ability of Glossina palpalis to adapt to urban areas and to transmit trypanosomosis in such areas. The factors leading to a possible emergence of canine trypanosomiasis in enzootic zones need further investigations.
Assuntos
Doenças do Cão/epidemiologia , Tripanossomíase Africana/veterinária , Animais , Côte d'Ivoire/epidemiologia , Doenças do Cão/genética , Doenças do Cão/parasitologia , Cães , Predisposição Genética para Doença , Prevalência , Trypanosoma congolense , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/genética , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/parasitologia , População UrbanaRESUMO
Despite the impact of some trypanosome species on human and livestock health, the full diversity of trypanosomes in Africa is poorly understood. A recent study examined the prevalence of trypanosomes among a wide variety of wild vertebrates in Cameroon using species-specific PCR tests, but six trypanosome isolates remained unidentified. Here they have been re-examined using fluorescent fragment length barcoding (FFLB) and phylogenetic analysis of glycosomal glyceraldehyde phosphate dehydrogenase gGAPDH and 18S ribosomal RNA (rDNA) genes. Isolates from a monkey (Cercopithecus nictitans) and a palm civet (Nandinia binotata) belonged to the Trypanosoma cruzi clade, known previously only from New World and Australian terrestrial mammals, and bats from Africa, Europe and South America. Of the four other isolates, three from antelope were identified as Trypanosoma theileri, and one from a crocodile as T. grayi. This is the first report of trypanosomes of the T. cruzi clade in African terrestrial mammals and expands the clade's known global distribution in terrestrial mammals. Previously it has been hypothesized that African and New World trypanosomes diverged after continental separation, dating the divergence to around 100 million years ago. The new evidence instead suggests that intercontinental transfer occurred well after this, possibly via bats or rodents, allowing these trypanosomes to establish and evolve in African terrestrial mammals, and questioning the validity of calibrating trypanosome molecular trees using continental separation.
Assuntos
Genes de Protozoários , Mamíferos/parasitologia , Filogenia , Trypanosoma cruzi/genética , Trypanosoma/classificação , Trypanosoma/genética , Tripanossomíase Africana/veterinária , Jacarés e Crocodilos/parasitologia , Animais , Antílopes/parasitologia , Camarões , Cercopithecus/parasitologia , DNA Ribossômico/genética , Evolução Molecular , Variação Genética , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Dados de Sequência Molecular , Nandiniidae/parasitologia , RNA Ribossômico 18S/genética , Alinhamento de Sequência , Trypanosoma cruzi/classificação , Tripanossomíase Africana/parasitologiaRESUMO
The first outbreak of trypanosomosis caused by Trypanosoma evansi in camels in France was reported on a farm in the Aveyron Department. Five camels were imported from the Canary Islands to the farm in early July 2006, and trypanosomes were observed on a stained blood smear from one of them, which died in October. On further investigations, trypanosomes were observed in the blood of five camels, three of them indigenous to the farm and two that had been imported. On the basis of microscopical examination (morphological criteria and measurements) and serological results based on the card agglutination T evansi test and PCR typing, the parasites were identified as T evansi. After treatment with melarsomine, the infected camels rapidly became negative by parasitological tests and were negative two to four months later by serological tests. The parasite was probably transmitted by tabanids and Stomoxys calcitrans, which were abundant in July to September 2006. No parasites were observed in other animals on the farm or on neighbouring farms, but some of the sheep on these farms were positive by PCR or serology.
Assuntos
Camelus/parasitologia , Surtos de Doenças/veterinária , Trypanosoma/classificação , Tripanossomíase/veterinária , Animais , Arsenicais/uso terapêutico , França/epidemiologia , Insetos Vetores/parasitologia , Muscidae/parasitologia , Triazinas/uso terapêutico , Tripanossomicidas/uso terapêutico , Trypanosoma/isolamento & purificação , Tripanossomíase/tratamento farmacológico , Tripanossomíase/epidemiologia , Tripanossomíase/parasitologiaRESUMO
OBJECTIVE: To review the geography and history of sleeping sickness (Human African trypanosomiasis; HAT) over the past 100 years in West Africa, to identify priority areas for sleeping sickness surveillance and areas where HAT no longer seems active. METHOD: History and geography of HAT were summarized based on a review of old reports and recent publications and on recent results obtained from medical surveys conducted in West Africa up to 2006. RESULTS/CONCLUSIONS: Active HAT foci seem to have moved from the North to the South. Endemic HAT presently appears to be limited to areas where annual rainfall exceeds 1200 mm, although the reasons for this remain unknown. There has also been a shift towards the south of the isohyets and of the northern distribution limit of tsetse. Currently, the most severely affected countries are Guinea and Ivory Coast, whereas the northern countries seem less affected. However, many parts of West Africa still lack information on HAT and remain to be investigated. Of particular interest are the consequences of the recent political crisis in Ivory Coast and the resulting massive population movements, given the possible consequences on HAT in neighbouring countries.
Assuntos
Doenças Endêmicas , Tripanossomíase Africana/epidemiologia , África Ocidental/epidemiologia , Criança , Clima , Emigração e Imigração , Doenças Endêmicas/história , História do Século XX , História do Século XXI , Humanos , Lactente , Fatores de Risco , Vigilância de Evento Sentinela , Conglomerados Espaço-Temporais , Tripanossomíase Africana/históriaRESUMO
To determine the tsetse fly host preferences in two sleeping sickness foci of southern Cameroon, four entomological surveys (two in each focus) were carried out. For the whole study, 4929 tsetse flies were caught: 3933 (79.8%) Glossina palpalis palpalis, 626 (12.7%) Glossina pallicera pallicera, 276 (5.6%) Glossina nigrofusca and 94 (1.9%) Glossina caliginea. One hundred and thirty-eight blood meals were collected and the origin of 118 (85.5%) meals was successfully identified: 38.4% from man, 23.9% from pig, 20.3% from sitatunga (Tragelaphus spekeii), 2.2% from sheep and 0.7% from golden cat (Profilis aurata). The number of Glossina palpalis palpalis with man blood meals is more important in the Human African Trypanosomiasis (HAT) focus showing endemic evolution (Campo) than in the focus (Bipindi) presenting a flare up of the disease. The consideration of both results of the prevalence of Trypanosoma brucei gambiense in vertebrate hosts and those of the tsetse fly host preferences indicates a wild animal reservoir of Gambian sleeping sickness and three transmission cycles (human, domestic and wild animals' cycles) in southern Cameroon HAT foci.
Assuntos
Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/fisiologia , Animais , Camarões/epidemiologia , Comportamento Alimentar/fisiologia , Feminino , Humanos , Masculino , Tripanossomíase Africana/sangueRESUMO
To understand the maintenance and resurgence of historical Human African Trypanosomiasis (HAT) foci, AFLP was used to genotype 100 Central African Trypanosoma brucei s.l. stocks. This technique confirmed the high genetic stability of T. b. gambiense group 1 stocks and the micro genetic variability within Central African T. b. gambiense stocks. It revealed several T. b. gambiense genotypes and allowed the identification of minor and major genotypes in HAT foci. The coexistence of these genotypes in the same focus suggests that clustering of stocks according to HAT focus does not provide the true genetic picture of trypanosome circulating within the disease focus because the minor genotypes are generally underestimated. The presence of minor and major genotypes in HAT foci may explain the persistence and the resurgence of Central African sleeping sickness foci.
Assuntos
Impressões Digitais de DNA/métodos , Polimorfismo de Fragmento de Restrição , Trypanosoma brucei gambiense/genética , Tripanossomíase Africana/parasitologia , África Central , Animais , Análise por Conglomerados , DNA de Protozoário/química , Eletroforese em Gel de Poliacrilamida , Genética Populacional , Humanos , Filogenia , Suínos , Trypanosoma brucei gambiense/classificaçãoRESUMO
Parasitic manipulations of host behaviour are known from a wide range of host-parasite associations. However, the understanding of these phenomena is far from complete and detailed investigation of their proximate causes is needed. Many studies report behavioural modifications, such as altered feeding rates in tsetse fly (Glossina) infected with the mature transmissible stage (i.e. metacyclic) of the trypanosomes. Here, bidimensional (2D) gel electrophoresis and mass spectrometry were employed to analyse and compare the head proteome between four Glossina palpalis gambiensis categories (uninfected, refractory, mature infection, immature infection). Twenty-four protein spots specifically present or absent in the head of metacyclic-infected flies were observed. These protein spots were subsequently identified and functionally classified as glycolitic, neurotransmiter synthesis, signalling, molecular chaperone and transcriptional regulation proteins. Our results indicate altered energy metabolism in the head of metacyclic-infected tsetse flies. Some of the proteins identified, such as casein kinase 2 and jun kinase have previously been shown to play critical roles in apoptosis in insect neurones. In addition, we found two pyridoxal-dependent decarboxylases (dopa decarboxylase and alpha methyldopa hypersensitive protein), suggesting a modification of serotonin and/or dopamine in the brain of metacyclic-infected tsetse flies. Our data pave the way for future investigation of the alteration of the glossina central nervous system during infection by trypanosomes.
Assuntos
Proteoma/metabolismo , Trypanosoma brucei brucei/patogenicidade , Moscas Tsé-Tsé/metabolismo , Moscas Tsé-Tsé/parasitologia , Animais , Comportamento Animal , Eletroforese em Gel Bidimensional , Metabolismo Energético , Regulação da Expressão Gênica , Glicólise , Interações Hospedeiro-Parasita , Proteínas de Insetos/isolamento & purificação , Proteínas de Insetos/metabolismo , Insetos Vetores/genética , Insetos Vetores/metabolismo , Insetos Vetores/parasitologia , Neurotransmissores/metabolismo , Proteoma/isolamento & purificação , Transdução de Sinais , Moscas Tsé-Tsé/genéticaRESUMO
Glossina palpalis is the main vector of human African trypanosomosis (HAT, or sleeping sickness) that dramatically affects human health in sub-Saharan Africa. Because of the implications of genetic structuring of vector populations for the design and efficacy of control campaigns, G. palpalis palpalis in the most active focus of sleeping sickness in Côte d'Ivoire was studied to determine whether this taxon is genetically structured. High and statistically significant levels of within population heterozygote deficiencies were found at each of the five microsatellite loci in two temporally separated samples. Neither null alleles, short allele dominance, nor trap locations could fully explain these deviations from random mating, but a clustering within each of the two samples into different genetic sub-populations (Wahlund effect) was strongly suggested. These different genetic groups, which could display differences in infection rates and trypanosome identity, were composed of small numbers of individuals that were captured together, leading to the observed Wahlund effect. Implications of this population structure on tsetse control are discussed.
Assuntos
Tripanossomíase Africana/parasitologia , Moscas Tsé-Tsé/classificação , Moscas Tsé-Tsé/genética , Animais , Côte d'Ivoire/epidemiologia , Feminino , Humanos , Insetos Vetores/parasitologia , Masculino , Filogenia , Tripanossomíase Africana/epidemiologia , Tripanossomíase Africana/transmissão , Moscas Tsé-Tsé/parasitologiaRESUMO
Six sets of teneral Glossina palpalis gambiensis (Diptera: Glossinidae) were fed on mice infected with six different isolates of Trypanosoma brucei gambiense (each mouse was infected with one of the isolates), previously isolated from patients in the sleeping sickness focus of Bonon, Côte d'Ivoire and in Makoua, Congo. All the tsetse flies were dissected 42 days post-infection and midgut and salivary glands were examined for trypanosomes by microscopical examination. No infection was observed with the reference stock whereas each of the five recently isolated trypanosome isolates was able to infect tsetse flies, with rates of infection varying between 9.7 and 18.2% depending on the isolate. Three isolates displayed only immature infections with 9.7, 17.3 and 18% of the flies showing trypanosomes in their midgut. One isolate gave both immature (12.1%) and mature infections (6.1%). Finally, the last isolate involved only mature infections in 9.7% of the Glossina species examined. These substantial differences in the cyclical transmission of T. b. gambiense in the same fly species could have important implications for the epidemiology of the transmission of Human African Trypanosomiasis.
Assuntos
Trypanosoma brucei gambiense/patogenicidade , Moscas Tsé-Tsé/parasitologia , Animais , Sistema Digestório/parasitologia , Humanos , Masculino , Camundongos , Glândulas Salivares/parasitologia , Trypanosoma brucei gambiense/fisiologia , Tripanossomíase Africana/parasitologiaRESUMO
The serological and parasitological tests used for Trypanosoma brucei gambiense human African trypanosomiasis (HAT) diagnosis have low specificity and sensitivity, respectively, and in the field, control program teams are faced with subjects with positive serology but negative parasitology who remain untreated. The aim of this work was to explore, using PCR tool, the significance of these aparasitemic serological suspects. Since discordant PCR results have been observed earlier with different extraction methods, two DNA extraction methods were compared (the Chelex 100 resin and the DNeasy Tissue kit). The study was conducted on 604 blood samples: 574 from parasitologically confirmed patients, aparasitemic serological suspects and endemic controls collected in Côte d'Ivoire and 30 from healthy volunteers collected in France. No significant differences were observed between the PCR results obtained with the two extraction methods. Concerning PCR, problems of reproducibility and discordances with both serological and parasitological test results were observed, mainly for the aparasitemic serological suspects. In addition to previous results that pointed to the existence of non-virulent or non-pathogenic trypanosome strains and of individual susceptibility leading to long term seropositivity without detectable parasitaemia but positive PCR, the results of this study support the notion of a long lasting human reservoir that may contribute to the maintenance or periodic resurgences of HAT in endemic foci.