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Photovoice is a participatory, photo-based research method that differs from conventional (non-participatory) research in that the process is meant to be empowering and beneficial. However, empirical research on the Photovoice process remains very limited. Based on feedback from participants who reported Photovoice helped them develop closer relationships, we examine whether engaging in Photovoice fosters social support. Transcripts from a Photovoice study on wellness in mental health Clubhouses (voluntary, community mental health centers) were retrospectively analyzed for instrumental support, appraisal, informational support, and emotional support. Appraisal was the most common form of social support identified, and was primarily expressed through peer praise for photos and insights. Informational support included advice on managing symptoms, promoting wellness, and navigating challenges. Instrumental support was fostered by learning the tangible skill of digital photography and by supporting fellow members with physical or visual limitations to participate in the process. Emotional support was cultivated through encouragement, identification of shared experiences, and connection through humor. In sum, the findings suggest that Photovoice has the potential to foster social support, which may support relational empowerment.
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Investigación Participativa Basada en la Comunidad , Apoyo Social , Humanos , Investigación Participativa Basada en la Comunidad/métodos , Estudios Retrospectivos , Fotograbar , Investigación CualitativaRESUMEN
Although vaccines have been developed to prevent COVID-19, vaccine hesitancy is a significant barrier for vaccination programs. Most research on COVID-19 vaccine hesitancy has blamed misinformation and misstated concerns about effectiveness, safety, and side effects of these vaccines. The preponderance of these studies has been performed in the Global North. Although Latin American has been substantially and negatively impacted by COVID-19, few studies have examined COVID-19 vaccine hesitancy there. We explored reasons volunteered for COVID-19 vaccine hesitancy from a sample of 1,173 Colombians, Ecuadorians, and Venezuelans. Overall, COVID-19 vaccine hesitancy in these three countries is higher than desirable, but most people who are COVID-19 vaccine hesitant offered one reason or fewer. The reasons offered are diverse, including myths and exaggerations, but also individual-level contraindications for vaccination and structural barriers. Because of the diversity of reasons, single-issue mass campaigns are unlikely to bring about large shifts in COVID-19 vaccine hesitancy in Colombia, Ecuador, and Venezuela. Our data suggest that interpersonal communication, particularly in Ecuador, and addressing structural concerns, particularly in Venezuela, are likely to have the greatest impact on vaccine uptake.
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COVID-19 , Vacunas , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19/uso terapéutico , Colombia/epidemiología , Ecuador , Humanos , América Latina , Vacilación a la Vacunación , VenezuelaRESUMEN
Individuals with severe mental illness need to be engaged in defining their own vision of wellness to promote equity and reduce disparities. This photovoice study helps define what wellness is and how it is achieved in mental health Clubhouses in Hawai'i. Results from a photovoice study with 43 members and staff were analyzed using Pilinaha, a Native Hawaiian framework for health. Pilinaha envisions health through connection to place, community, past and future, and one's better self. Within Clubhouses, connection to place included connection to 'aina (land) and the access to a safe space. Connection to community occurred through reciprocal social support, which developed kuleana (responsibility), and a sense of 'ohana (family) for many members who were previously isolated. Connection to one's better self-involved positive identity change, development of hope, and pursuing opportunities within and outside the Clubhouse. Connection to past and future was described through individual narratives, remembering members who had died, and connection to cultural traditions. Overall, wellness was conceptualized as the ability to work toward dreams, engage in cultural practice, and feel accepted, respected, and valued-to be treated with aloha. Findings provide a culturally responsive perspective on wellness and illustrate the value of Clubhouses as a space for mental health recovery and transformative change.
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Equidad en Salud , Promoción de la Salud/métodos , Servicios de Salud del Indígena , Trastornos Mentales/terapia , Adulto , Femenino , Hawaii , Humanos , Masculino , Salud Mental , Persona de Mediana Edad , Fotograbar , Apoyo SocialRESUMEN
OBJECTIVE: People with serious mental illness (PWSMI) experience dramatic disparities in health, quality of life, and longevity. Mental health Clubhouses are a community-based treatment model that can positively affect health and quality of life among PWSMI. However, few studies investigate the processes within Clubhouses and what factors are related to the improvement of health and quality of life among members. To address this gap, this research offers a conceptual model of how Clubhouses contribute to health and quality of life. METHOD: This conceptual model was created using participatory qualitative methods, combining Photovoice and grounded theory. Forty-two participants (37 Clubhouse members and six staff) from four Clubhouses in Hawai'i were engaged in 22 sessions over the course of 2 years. RESULTS: The conceptual model begins with quality of participation in Clubhouse activities, which refers not only to being present in the Clubhouse but being actively and meaningfully engaged in Clubhouse activities. Engagement in Clubhouse activities and working side-by-side with members and staff led to reciprocal social support. As members were supported and supported others, they gained a sense that they mattered, and they perceived themselves as more capable, more efficacious, and less stigmatized over time. They became a contributing member of a community, which supported health and quality of life directly and indirectly. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: This work offers a novel conceptual framework of Clubhouse processes that highlights the importance and potential of empowering psychosocial treatment models. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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OBJECTIVE: This study examines adaptations, successes, and persistent challenges engaging members in virtual or hybrid community-based psychosocial rehabilitation centers called Clubhouses. METHODS: Fifteen members and staff from five Clubhouses across two Hawaiian Islands participated in a virtual Photovoice process. RESULTS: Results illustrated several unexpected positive outcomes from the transition to hybrid or virtual formats including opportunities for growth, learning new technology, cross-Clubhouse collaborations, deepened relationships, and better access to some hard-to-reach members. Persistent challenges included members reporting "something missing" in the socioemotional quality of virtual engagement and losing members who had low digital literacy or who preferred in-person engagement. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: Overall, participants described that virtual Clubhouse supported their wellness by fostering a sense of purpose, companionship, and potential, despite sustained uncertainty from the COVID-19 pandemic. However, they also made clear that virtual and hybrid formats should be a complement to, not a replacement for, in-person Clubhouse services. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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OBJECTIVE: Social support is an important component of recovery-based interventions for individuals living with severe mental illness (IWSMI). Clubhouses are local community centers that facilitate the development of meaningful relationships among IWSMI through an empowering structure and engagement with the work-ordered day. This review synthesizes research on social networks in Clubhouses to provide insights on the role of supportive relationships in mental illness recovery, including the size and features of social networks of Clubhouse members, methodological trends and gaps, and the associations between social networks and demographic variables, recovery, health, and perceived social support. METHOD: Research on social networks within Clubhouses were identified and analyzed following a systematic six-stage scoping review design. RESULTS: Twelve articles across six studies were included. Results revealed considerable variation in social network interview methods and network size and features. Overall findings suggest that network size is not consistently associated with reported loneliness, social support, recovery, or quality of life. A deep relationship with at least one supportive person, level of perceived affiliation with Clubhouses, or positive comments from network members may be more or equally valuable than a larger network. Some studies found that types of relationships were associated with unique benefits. Stronger peer networks were associated with relationship satisfaction, while increased connections with health care professionals and family were associated with reduced hospitalizations. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: Future research should diversify research designs, expand the use of social network analysis and visualization, measure additional outcomes including recovery and health, and increase sample diversity. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Trastornos Mentales , Calidad de Vida , Humanos , Apoyo Social , Grupo Paritario , Red SocialRESUMEN
Health literacy is the ability to obtain and utilize health information to make health-related decisions and to navigate health systems. Although health literacy has traditionally been understood as an individual-level construct, current research is revealing the impact that social networks can have on health literacy. To date, no studies have examined associations between health literacy and social networks among people with serious mental illness (PWSMI), who are at high risk of physical illness and premature mortality. To begin to fill this gap, this study explores associations between health literacy, relationships with health discussion partners, and self-reported health outcomes in a racially diverse sample of Clubhouse members in Hawai'i. Clubhouses are community mental health centers that promote recovery from mental illness through destigmatization, meaningful activity, and strong social relationships. Health literacy was assessed using two single-item screeners (SILS). In a sample of 163 members, 56.2% reported adequate ability to understand health-related instructions or pamphlets, and 43.3% reported adequate confidence filling out medical forms independently. This is consistent with other health literacy studies with PWSMI in the United States, and indicates lower health literacy within this group than is reported in national averages. Multivariate logistic regression revealed a larger Clubhouse staff social network and completing high school were significantly associated with requiring less help to read materials. Higher age, male gender, and being Native Hawaiian and/or Pacific Islander were associated with less confidence filling out medical forms, while higher self-efficacy was associated with higher confidence filling out medical forms. This study provides preliminary evidence that relationships fostered within Clubhouses are associated with health literacy among PWSMI, and highlights the need for more research to examine how social networks and health literacy interventions can be leveraged in community mental health settings to improve health outcomes within this vulnerable population.
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Alfabetización en Salud , Trastornos Mentales , Humanos , Masculino , Salud Mental , Hawaii , Trastornos Mentales/epidemiología , Trastornos Mentales/psicología , Red Social , Evaluación de Resultado en la Atención de SaludRESUMEN
Trypanosomes are blood-borne parasites infecting a range of mammalian hosts worldwide. In Australia, an increasing number of novel Trypanosoma species have been identified from various wildlife hosts, some of which are critically endangered. Trypanosoma noyesi is a recently described species of biosecurity concern, due to a close relationship to the South American human pathogen, Trypanosoma cruzi. This genetic similarity increases the risk for introduction of T. cruzi via a local vector. Unfortunately, there is a lack of knowledge concerning the vectorial capacity of Australian invertebrates for native Trypanosoma species. Australian ixodid ticks (Ixodidae), which are widespread ectoparasites of mammalian wildlife, have received the most attention as likely candidates for trypanosome transmission and have been previously implicated as vectors. However, as all studies to date have focused on blood-fed ticks collected directly from infected mammalian hosts, the question of whether ticks maintain a trypanosome infection between blood meals is unknown. In this study, we investigated the presence of Trypanosoma within 148 Australian adult and nymph questing ticks of the species Amblyomma triguttatum, Ixodes australiensis, Ixodes myrmecobii and larvae Ixodes spp., collected from an endemic region of south-west Australia. Using a novel HRM-qPCR detection method that can discriminate between species of Trypanosoma based on primer melting temperature (Tm), we report the first molecular detection of Trypanosoma DNA in Australian questing ticks, with 6 ticks DNA positive for T. noyesi. Additionally, the presence of intact T. noyesi parasites within all (n = 3) smeared gut and gland contents of questing ticks was confirmed using a fluorescence in situ hybridisation (FISH) assay. Whilst this study was unable to determine the in situ tissue location of trypanosomes for the purpose of discerning a potential route of transmission, these combined molecular and FISH smear data indicate that trypanosomes can persist in ticks between blood meals and that ticks are possibly vectors in the transmission of T. noyesi between native wildlife. Transmission experiments are still required to evaluate the competency of Australian ticks as vectors for T. noyesi. Nevertheless, these novel findings warrant further investigation concerning potential life stages and the development of trypanosomes in both Australian, and other, tick species.
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Ixodidae/parasitología , Trypanosoma/aislamiento & purificación , Animales , Femenino , Hibridación Fluorescente in Situ , Ixodidae/crecimiento & desarrollo , Larva/crecimiento & desarrollo , Larva/parasitología , Masculino , Ninfa/crecimiento & desarrollo , Ninfa/parasitología , Australia OccidentalRESUMEN
Kinetoplast DNA (kDNA) is the mitochondrial genome of trypanosomatids. It consists of a few dozen maxicircles and several thousand minicircles, all catenated topologically to form a two-dimensional DNA network. Minicircles are heterogeneous in size and sequence among species. They present one or several conserved regions that contain three highly conserved sequence blocks. CSB-1 (10â¯bp sequence) and CSB-2 (8â¯bp sequence) present lower interspecies homology, while CSB-3 (12â¯bp sequence) or the Universal Minicircle Sequence is conserved within most trypanosomatids. The Universal Minicircle Sequence is located at the replication origin of the minicircles, and is the binding site for the UMS binding protein, a protein involved in trypanosomatid survival and virulence. Here, we describe the structure and organisation of the kDNA of Trypanosoma copemani, a parasite that has been shown to infect mammalian cells and has been associated with the drastic decline of the endangered Australian marsupial, the woylie (Bettongia penicillata). Deep genomic sequencing showed that T. copemani presents two classes of minicircles that share sequence identity and organisation in the conserved sequence blocks with those of Trypanosoma cruzi and Trypanosoma lewisi. A 19,257â¯bp partial region of the maxicircle of T. copemani that contained the entire coding region was obtained. Comparative analysis of the T. copemani entire maxicircle coding region with the coding regions of T. cruzi and T. lewisi showed they share 71.05% and 71.28% identity, respectively. The shared features in the maxicircle/minicircle organisation and sequence between T. copemani and T. cruzi/T. lewisi suggest similarities in their process of kDNA replication, and are of significance in understanding the evolution of Australian trypanosomes.
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ADN de Cinetoplasto/genética , ADN Protozoario/genética , Trypanosoma/genética , Animales , Australia , Secuencia de Bases , Secuencia Conservada , Filogenia , Trypanosoma/ultraestructuraRESUMEN
During monitoring of critically endangered woylie (Bettongia penicillata) populations within the south-west of Western Australia, an adult female woylie was euthanased after being found in extremely poor body condition with diffuse alopecia, debilitating skin lesions and severe ectoparasite infestation. Trypanosoma copemani G2 and Sarcocystis sp. were detected molecularly within tissue samples collected post-mortem. Potorostrongylus woyliei and Paraustrostrongylus sp. nematodes were present within the stomach and small intestine, respectively. Blood collected ante-mortem revealed the presence of moderate hypomagnesaemia, mild hypokalaemia, mild hyperglobulinaemia and mild hypoalbuminaemia. Diffuse megakaryocytic hypoplasia was evident within the bone marrow. We propose various hypotheses that may explain the presence of severe ectoparasite infection, skin disease and poor body condition in this woylie. Given the potential deleterious effects of parasite infection, the importance of monitoring parasites cannot be over-emphasised.
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Understanding the impacts of parasites on wildlife is growing in importance as diseases pose a threat to wildlife populations. Woylie (syn. brush-tailed bettong, Bettongia penicillata) populations have undergone enigmatic declines in south-western Western Australia over the past decade. Trypanosomes have been suggested as a possible factor contributing towards these declines because of their high prevalence in the declining population. We asked whether temporal patterns of infection with Trypanosoma spp. were associated with the decline patterns of the host, or if other factors (host sex, body condition, co-infection or rainfall) were more influential in predicting infection patterns. Species-specific nested PCRs were used to detect the two most common trypanosomes (T. copemani and T. vegrandis) from 444 woylie blood samples collected between 2006 and 2012. Time relative to the decline (year) and an interaction with co-infection by the other trypanosome best explained patterns of infection for both trypanosomes. The prevalence of single species infections for both T. copemani and T. vegrandis was lower after the population crash, however, the occurrence of co-infections increased after the crash compared to before the crash. Our results suggest an interaction between the two parasites with the decline of their host, leading to a higher level of co-infection after the decline. We discuss the possible mechanisms that may have led to a higher level of co-infection after the population crash, and highlight the importance of considering co-infection when investigating the role of parasites in species declines.
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Trypanosomes are blood protozoan parasites that are capable of producing illness in the vertebrate host. Within Australia, several native Trypanosoma species have been described infecting wildlife. However, only Trypanosoma copemani has been associated with pathological lesions in wildlife hosts and more recently has been associated with the drastic decline of the critically endangered woylie (Bettongia penicillata). The impact that some trypanosomes have on the health of the vertebrate host has led to the development of numerous drug compounds that could inhibit the growth or kill the parasite. This study investigated and compared the in vitro susceptibility of two strains of T. copemani (G1 and G2) and one strain of Trypanosoma cruzi (10R26) against drugs that are known to show trypanocidal activity (benznidazole, posaconazole, miltefosine and melarsoprol) and against four lead compounds, two fenarimols and two pyridine derivatives (EPL-BS1937, EPL-BS2391, EPL-BS0967, and EPL-BS1246), that have been developed primarily against T.cruzi. The in vitro cytotoxicity of all drugs against L6 rat myoblast cells was also assessed. Results showed that both strains of T. copemani were more susceptible to all drugs and lead compounds than T. cruzi, with all IC50 values in the low and sub-µM range for both species. Melarsoprol and miltefosine exhibited the highest drug activity against both T. copemani and T. cruzi, but they also showed the highest toxicity in L6 cells. Interestingly, both fenarimol and pyridine derivative compounds were more active against T. copemani and T. cruzi than the reference drugs benznidazole and posaconazole. T. copemani strains exhibited differences in susceptibility to all drugs demonstrating once again considerable differences in their biological behaviour.
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Animales Salvajes/parasitología , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Trypanosoma/efectos de los fármacos , Animales , Australia , Línea Celular , Descubrimiento de Drogas , Ensayos Analíticos de Alto Rendimiento , Concentración 50 Inhibidora , Melarsoprol/farmacología , Melarsoprol/toxicidad , Nitroimidazoles/farmacología , Fosforilcolina/análogos & derivados , Fosforilcolina/farmacología , Fosforilcolina/toxicidad , Potoroidae/parasitología , Pirimidinas/farmacología , Triazoles/farmacología , Trypanosoma/aislamiento & purificación , Trypanosoma cruzi/aislamiento & purificaciónRESUMEN
BACKGROUND: Molecular and structural information on avian Trypanosoma spp. throughout Australia is limited despite their intrinsic value in understanding trypanosomatid evolution, diversity, and structural biology. In Western Australia tissue samples (n = 429) extracted from 93 birds in 25 bird species were screened using generic PCR primers to investigate the diversity of Trypanosoma spp. To investigate avian trypanosome structural biology the first 3-dimensional ultrastructural models of a Trypanosoma spp. (Trypanosoma sp. AAT) isolated from a bird (currawong, Strepera spp.) were generated using focussed ion beam milling combined with scanning electron microscopy (FIB-SEM). RESULTS: Here, we confirm four intercontinental species of avian trypanosomes in native Australian birds, and identify a new avian Trypanosoma. Trypanosome infection was identified in 18 birds from 13 different bird species (19%). A single new genotype was isolated and found to be closely related to T. culicavium (Trypanosoma sp. CC2016 B002). Other Trypanosoma spp. identified include T. avium, T. culicavium, T. thomasbancrofti, Trypanosoma sp. TL.AQ.22, Trypanosoma sp. AAT, and an uncharacterised Trypanosoma sp. (group C-III sensu Zidková et al. (Infect Genet Evol 12:102-112, 2012)), all previously identified in Australia or other continents. Serially-sectioning Trypanosoma sp. AAT epimastigotes using FIB-SEM revealed the disc-shaped kinetoplast pocket attached perpendicular to the branching mitochondrion. Additionally, the universal minicircle sequence within the kinetoplast DNA and the associated binding protein were determined in Trypanosoma sp. AAT. CONCLUSIONS: These results indicate that bird trypanosomes are relatively conserved across continents, while being locally diverse, which supports the hypothesis that bird trypanosomes exist as fewer species than described in the literature. Evidence exists that avian Trypanosoma spp. are infecting mammals and could be transmitted by haemadipsid leeches. Trypanosoma sp. AAT is most likely a separate species currently found only in Australia and the first 3-dimentional ultrastructural analysis of an avian trypanosome provides interesting information on their morphology and organelle arrangement.
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Enfermedades de las Aves/parasitología , Trypanosoma/genética , Trypanosoma/ultraestructura , Tripanosomiasis/veterinaria , Animales , Australia/epidemiología , Enfermedades de las Aves/epidemiología , ADN de Cinetoplasto/genética , ADN Protozoario/genética , ADN Ribosómico , Geografía , Imagenología Tridimensional/métodos , Microscopía Electrónica de Rastreo/métodos , Mitocondrias/ultraestructura , Filogenia , Reacción en Cadena de la Polimerasa , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADN , Trypanosoma/clasificación , Trypanosoma/aislamiento & purificación , Tripanosomiasis/epidemiología , Tripanosomiasis/parasitologíaRESUMEN
Trypanosoma copemani has been found infecting several threatened/endangered marsupial species within Australia and is thought to be a key player in the rapid decline of the woylie (Bettongia penicillata). To better understand the biology and life cycle of this parasite, the growth requirements, and kinetics of infection of two newly described genotypes, T. copemani G1 and G2, were investigated and compared with the T. cruzi strain-10R26 in vitro. Both G1 and G2 were able to infect all four cell lines tested. The number of infected cells where at least one intracellular amastigote of T. copemani G1 and G2 was seen was below 7% and 15% respectively in most cell lines. However, in VERO cells the rate of infection for T. copemani G2 was 70%-approximately seven and two times higher than for G1 and T. cruzi respectively. Despite the higher infection rate, the number of intracellular forms of T. copemani G2 was lower compared with T. cruzi, and intracellular replicating forms were not observed. The capability of T. copemani G2 to infect cells may have important consequences for pathogenicity and suggests it might employ similar strategies to complete its life cycle in the vertebrate host to those seen in T. cruzi.
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Potoroidae , Trypanosoma/fisiología , Tripanosomiasis/veterinaria , Animales , Australia , Chlorocebus aethiops , Interacciones Huésped-Parásitos , Trypanosoma/genética , Trypanosoma/crecimiento & desarrollo , Tripanosomiasis/parasitología , Células VeroRESUMEN
A number of trypanosome isolates from Australian marsupials are within the clade containing the human pathogen Trypanosoma cruzi. Trypanosomes within this clade are thought to have diverged from a common ancestral bat trypanosome. Here, we characterise Trypanosoma noyesi sp. nov. isolated from the critically endangered woylie (Bettongia pencillata) using phylogenetic inferences from three gene regions (18S rDNA, gGAPDH, and CytB) coupled with morphological and behavioural observations in vitro. We also investigated potential vectors and the presence of T. noyesi in the grey-headed flying fox (Pteropus poliocephalus). Phylogenetic analysis revealed T. noyesi and similar genotypes grouped at the periphery of the T. cruzi clade. T. noyesi is morphologically distinct both from other species of Australian trypanosomes and those within the T. cruzi clade. Although trypanosomes were not observed in the digestive tract of ectoparasites and biting flies collected from T. noyesi infected marsupials, tabanid and biting midges tested positive for T. noyesi DNA, indicating they are vector candidates. Tissues from flying foxes were negative for T. noyesi. This study provides novel information on the morphology and genetic variability of an Australian trypanosome within the T. cruzi clade.
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Quirópteros , Potoroidae , Trypanosoma/clasificación , Tripanosomiasis/veterinaria , Animales , Vectores Artrópodos , Dípteros/parasitología , Proteínas Protozoarias/genética , ARN Protozoario/genética , ARN Ribosómico 18S/genética , Trypanosoma/genética , Tripanosomiasis/epidemiología , Tripanosomiasis/parasitología , Australia OccidentalRESUMEN
BACKGROUND: The trypanosome diversity of the Brush-tailed Bettong (Bettongia penicillata), known locally as the woylie, has been further investigated. At a species level, woylies are critically endangered and have declined by 90% since 1999. The predation of individuals made more vulnerable by disease is thought to be the primary cause of this decline, but remains to be proven. METHODS: Woylies were sampled from three locations in southern Western Australia. Blood samples were collected and analysed using fluorescence in situ hybridization, conventional staining techniques and microscopy. Molecular techniques were also used to confirm morphological observations. RESULTS: The trypanosomes in the blood of woylies were grouped into three morphologically distinct trypomastigote forms, encompassing two separate species. The larger of the two species, Trypanosoma copemani exhibited polymorphic trypomastigote forms, with morphological phenotypes being distinguishable, primarily by the distance between the kinetoplast and nucleus. The second trypanosome species was only 20% of the length of T. copemani and is believed to be one of the smallest recorded trypanosome species from mammals. No morphological polymorphism was identified for this genetically diverse second species. We described the trypomastigote morphology of this new, smaller species from the peripheral blood of the woylie and proposed the name T. vegrandis sp. nov. Temporal results indicate that during T. copemani Phenotype 1 infections, the blood forms remain numerous and are continuously detectable by molecular methodology. In contrast, the trypomastigote forms of T. copemani Phenotype 2 appear to decrease in prevalence in the blood to below molecular detectable levels. CONCLUSIONS: Here we report for the first time on the morphological diversity of trypanosomes infecting the woylie and provide the first visual evidence of a mixed infection of both T. vegrandis sp. nov and T. copemani. We also provide supporting evidence that over time, the intracellular T. copemani Phenotype 2 may become localised in the tissues of woylies as the infection progresses from the active acute to chronic phase. As evidence grows, further research will be necessary to investigate whether the morphologically diverse trypanosomes of woylies have impacted on the health of their hosts during recent population declines.
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Potoroidae/parasitología , Trypanosoma/clasificación , Trypanosoma/citología , Tripanosomiasis/parasitología , Tripanosomiasis/veterinaria , Animales , Sangre/parasitología , Hibridación Fluorescente in Situ , Microscopía , Análisis de Secuencia de ADN , Coloración y Etiquetado , Trypanosoma/genética , Trypanosoma/aislamiento & purificación , Australia OccidentalRESUMEN
While much is known of the impact of trypanosomes on human and livestock health, trypanosomes in wildlife, although ubiquitous, have largely been considered to be non-pathogenic. We describe the genetic diversity, tissue tropism and potential pathogenicity of trypanosomes naturally infecting Western Australian marsupials. Blood samples collected from 554 live-animals and 250 tissue samples extracted from 50 carcasses of sick-euthanized or road-killed animals, belonging to 10 species of marsupials, were screened for the presence of trypanosomes using a PCR of the 18S rDNA gene. PCR results revealed a rate of infection of 67% in blood and 60% in tissues. Inferred phylogenetic trees using 18S rDNA and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) sequences showed the presence of eight genotypes that clustered into three clades: a clade including Trypanosoma copemani, a new clade closely related to Trypanosoma gilletti, and a clade including Trypanosoma H25 from an Australian kangaroo. Trypanosome infections were compared in a declining and in a stable population of the endangered Australian marsupial, the brush tailed bettong or woylie (Bettongia penicillata). This marsupial showed high rates of infection with Clade A genotypes (96%) in the declining population, whereas in the stable population, Clade B genotypes were predominant (89%). Mixed infections were common in woylies from the declining but not from the stable population. Histopathological findings associated with either mixed or single infections involving Clade A genotypes, showed a strong inflammatory process and tissue degeneration predominantly in heart, oesophagus and tongue. Trypanosomes were successfully grown in culture and for the first time we demonstrate that a genotype within Clade A has the capacity to not only colonize different tissues in the host but also to invade cells in vitro. These results provide evidence for the potential role of trypanosomes in the decline of a formerly abundant marsupial that is now critically endangered.
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Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), is an increasing threat to global health. Available medicines were introduced over 40 years ago, have undesirable side effects, and give equivocal results of cure in the chronic stage of the disease. We report the development of two compounds, 6 and (S)-7, with PCR-confirmed curative activity in a mouse model of established T. cruzi infection after once daily oral dosing for 20 days at 20 mg/kg 6 and 10 mg/kg (S)-7. Compounds 6 and (S)-7 have potent in vitro activity, are noncytotoxic, show no adverse effects in vivo following repeat dosing, are prepared by a short synthetic route, and have druglike properties suitable for preclinical development.
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Enfermedad de Chagas/tratamiento farmacológico , Pirimidinas/farmacología , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Enfermedad de Chagas/parasitología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Pirimidinas/administración & dosificación , Pirimidinas/química , Relación Estructura-Actividad , Tripanocidas/administración & dosificación , Tripanocidas/químicaRESUMEN
We report the discovery of nontoxic fungicide fenarimol (1) as an inhibitor of Trypanosoma cruzi ( T. cruzi ), the causative agent of Chagas disease, and the results of structure-activity investigations leading to potent analogues with low nM IC(50)s in a T. cruzi whole cell in vitro assay. Lead compounds suppressed blood parasitemia to virtually undetectable levels after once daily oral dosing in mouse models of T. cruzi infection. Compounds are chemically tractable, allowing rapid optimization of target biological activity and drug characteristics. Chemical and biological studies undertaken in the development of the fenarimol series toward the goal of delivering a new drug candidate for Chagas disease are reported.
Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Pirimidinas/química , Pirimidinas/farmacología , Tripanocidas/química , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Línea Celular , Enfermedad de Chagas/metabolismo , Enfermedad de Chagas/parasitología , Modelos Animales de Enfermedad , Cromatografía de Gases y Espectrometría de Masas , Concentración 50 Inhibidora , Masculino , Ratones , Resonancia Magnética Nuclear Biomolecular , Pirimidinas/síntesis química , Pirimidinas/farmacocinética , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Tripanocidas/síntesis química , Tripanocidas/farmacocinéticaRESUMEN
Although Trypanosoma rangeli is harmless for humans, it is a serious problem since it may be confused with diagnosis of Trypanosoma cruzi, the etiologic agent of Chagas disease. Both parasites overlap geographically, share antigenic protein, and are able to infect the same Triatominae vector and vertebrate host, including human. Our objective was to differentiate T. cruzi and T. rangeli isolates from Colombia based on polymerase chain reaction (PCR) amplification of the minicircles followed by appropriate hybridization tests with selected DNA probes and restriction fragment length polymorphism (RFLP) analysis. We worked with highly characterized T. cruzi and T. rangeli isolates from different biologic origins and geographic areas of Colombia, and they were analyzed by RFLP and PCR amplification of variable region of minicircles and Southern blot analysis. Our results and experimental conditions demonstrate the usefulness of PCR amplification of the minicircles followed by Southern blot analysis to differentiate T. cruzi from T. rangeli, which can be highly important to improve diagnosis of Chagas disease.