Why is Plasmodium vivax a neglected tropical disease?
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ABSTRACT:
SUBMITTER: Carlton JM
PROVIDER: S-EPMC3125139 | biostudies-literature | 2011 Jun
REPOSITORIES: biostudies-literature
Publications
Why is Plasmodium vivax a neglected tropical disease?
Carlton Jane M JM Sina Barbara J BJ Adams John H JH
PLoS neglected tropical diseases 20110628 6
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Project description:The human malaria parasite Plasmodium vivax is responsible for 25-40% of the approximately 515 million annual cases of malaria worldwide. Although seldom fatal, the parasite elicits severe and incapacitating clinical symptoms and often causes relapses months after a primary infection has cleared. Despite its importance as a major human pathogen, P. vivax is little studied because it cannot be propagated continuously in the laboratory except in non-human primates. We sequenced the genome of P. vivax to shed light on its distinctive biological features, and as a means to drive development of new drugs and vaccines. Here we describe the synteny and isochore structure of P. vivax chromosomes, and show that the parasite resembles other malaria parasites in gene content and metabolic potential, but possesses novel gene families and potential alternative invasion pathways not recognized previously. Completion of the P. vivax genome provides the scientific community with a valuable resource that can be used to advance investigation into this neglected species.
| S-EPMC2651158 | biostudies-literature
Project description:Recent reports highlight the severity and the morbidity of disease caused by the long neglected malaria parasite Plasmodium vivax. Due to inherent difficulties in the laboratory-propagation of P. vivax, the biology of this parasite has not been adequately explored. While the proteome of P. falciparum, the causative agent of cerebral malaria, has been extensively explored from several sources, there is limited information on the proteome of P. vivax. We have, for the first time, examined the proteome of P. vivax isolated directly from patients without adaptation to laboratory conditions. We have identified 153 proteins from clinical P. vivax, majority of which do not show homology to any previously known gene products. We also report 29 new proteins that were found to be expressed in P. vivax for the first time. In addition, several proteins previously implicated as anti-malarial targets, were also found in our analysis. Most importantly, we found several unique proteins expressed by P. vivax.This study is an important step in providing insight into physiology of the parasite under clinical settings.
| S-EPMC3197670 | biostudies-literature
Project description:BackgroundCurrent understanding of the spatial epidemiology and geographical distribution of Plasmodium vivax is far less developed than that for P. falciparum, representing a barrier to rational strategies for control and elimination. Here we present the first systematic effort to map the global endemicity of this hitherto neglected parasite.Methodology and findingsWe first updated to the year 2010 our earlier estimate of the geographical limits of P. vivax transmission. Within areas of stable transmission, an assembly of 9,970 geopositioned P. vivax parasite rate (PvPR) surveys collected from 1985 to 2010 were used with a spatiotemporal Bayesian model-based geostatistical approach to estimate endemicity age-standardised to the 1-99 year age range (PvPR(1-99)) within every 5×5 km resolution grid square. The model incorporated data on Duffy negative phenotype frequency to suppress endemicity predictions, particularly in Africa. Endemicity was predicted within a relatively narrow range throughout the endemic world, with the point estimate rarely exceeding 7% PvPR(1-99). The Americas contributed 22% of the global area at risk of P. vivax transmission, but high endemic areas were generally sparsely populated and the region contributed only 6% of the 2.5 billion people at risk (PAR) globally. In Africa, Duffy negativity meant stable transmission was constrained to Madagascar and parts of the Horn, contributing 3.5% of global PAR. Central Asia was home to 82% of global PAR with important high endemic areas coinciding with dense populations particularly in India and Myanmar. South East Asia contained areas of the highest endemicity in Indonesia and Papua New Guinea and contributed 9% of global PAR.Conclusions and significanceThis detailed depiction of spatially varying endemicity is intended to contribute to a much-needed paradigm shift towards geographically stratified and evidence-based planning for P. vivax control and elimination.
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Project description:Mycetoma is considered a neglected tropical disease globally. However, data on its burden and the associated complications in Uganda are limited. Hence we aimed to estimate its burden in Uganda. Firstly, a systematic PubMed search for all studies of any design on mycetoma in Uganda without restriction to the year of publication was conducted. A retrospective review of all the biopsy reports at the Pathology Reference Laboratory, Department of Pathology, Makerere University, Kampala, Uganda from January 1950 to September 2019 was conducted to identify any reports on mycetoma histological diagnosis. During the 70-years study period, 30 cases were identified by the literature review, with 249 additional cases identified by review of biopsy reports (total of 279 cases). The average incidence was estimated at 0.32/100,000 persons and prevalence of 8.32/100,000 persons per decade. However, there was a general decline in the number of cases detected recently. Males and the age group of 21-30 years were the most affected by mycetoma in Uganda, and only 7% of the cases were children. The highest number of cases was recorded from Kampala (n = 30) and Jinja (n = 19) districts. The majority of the cases (68%) were referred from surgical units. The foot was the most affected part of the body (72%). Ten per cent of the cases had bone involvement of which 58% required amputation. Fungi were the most common causative agents (89%) followed by Nocardia species (5%) and Actinomycetes (4%). The index of clinical suspicion of mycetoma was low (45%) with a very large differential diagnosis. Mycetoma is a relatively rare disease in Uganda, mostly caused by fungi, and there is a big gap in data and epidemiological studies. More systematic studies are warranted to define the true burden of mycetoma in Uganda.
| S-EPMC7190103 | biostudies-literature
Project description:On June 9th, 2017 WHO categorized snakebite envenomation into the Category A of the Neglected Tropical Diseases. This new situation will allow access to new funding, paving the way for wider and deeper researches. It should also expand the accessibility of antivenoms. Let us hope that it also leads to cooperation among stakeholders, aiming at improving the management of snakebites in developing countries.
| S-EPMC5549382 | biostudies-other
Project description:BackgroundNeglected tropical diseases (NTDs) are closely related to poverty and affect over a billion people in developing countries. The unmet treatment needs cause high mortality and disability thereby imposing a huge burden with severe social and economic consequences. Although coordinated by the World Health Organization, various philanthropic organizations, national governments and the pharmaceutical industry have been making efforts in improving the situation, the control of NTDs is still inadequate and extremely difficult today. The lack of safe, effective and affordable medicines is a key contributing factor. This paper reviews the recent advances and some of the challenges that we are facing in the fight against NTDs.Main bodyIn recent years, a number of innovations have demonstrated propensity to promote drug discovery and development for NTDs. Implementation of multilateral collaborations leads to continued efforts and plays a crucial role in drug discovery. Proactive approaches and advanced technologies are urgently needed in drug innovation for NTDs. However, the control and elimination of NTDs remain a formidable task as it requires persistent international cooperation to make sustainable progresses for a long period of time. Some currently employed strategies were proposed and verified to be successful, which involve both mechanisms of 'Push' which aims at cutting the cost of research and development for industry and 'Pull' which aims at increasing market attractiveness. Coupled to this effort should be the exercise of shared responsibility globally to reduce risks, overcome obstacles and maximize benefits. Since NTDs are closely associated with poverty, it is absolutely essential that the stakeholders take concerted and long-term measures to meet multifaceted challenges by alleviating extreme poverty, strengthening social intervention, adapting climate changes, providing effective monitoring and ensuring timely delivery.ConclusionsThe ongoing endeavor at the global scale will ultimately benefit the patients, the countries they are living and, hopefully, the manufacturers who provide new preventive, diagnostic and therapeutic products.
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Project description:Onchocerciasis, or river blindness, is a neglected tropical disease caused by the filarial nematode Onchocerca volvulus that affects more than 37 million people, mainly in third world countries. Currently, the only approved drug available for mass treatment is ivermectin, however, drug resistance is beginning to emerge, thus, new therapeutic targets and agents are desperately needed to treat and cure this devastating disease. Chitin metabolism plays a central role in invertebrate biology due to the critical structural function of chitin for the organism. Taken together with its absence in mammals, targeting chitin is an appealing therapeutic avenue. Importantly, the chitinase OvCHT1 from O. volvulus was recently discovered, however, its exact role in the worm's metabolism remains unknown. A screening effort against OvCHT1 was conducted using the Johns Hopkins Clinical Compound Library that contains over 1,500 existing drugs. Closantel, a veterinary anthelmintic with known proton ionophore activities, was identified as a potent and specific inhibitor of filarial chitinases, an activity not previously reported for this compound. Notably, closantel was found also to completely inhibit molting of O. volvulus infective L3 stage larvae. Closantel appears to target two important biochemical processes essential to filarial parasites. To begin to unravel closantel's effects, a retro-fragment-based study was used to define structural elements critical for closantel's chitinase inhibitor function. As resources towards the development of new agents that target neglected tropical diseases are scant, the finding of an existing drug with impact against O. volvulus provides promise in the hunt for new therapies against river blindness.
| S-EPMC2840490 | biostudies-other
Project description:Scabies is a neglected tropical disease (NTD) with high prevalence rate in resource-limited settings. Though street children are susceptible because of lack of sanitation and contact with vectors, few attempts have been made to identify the lived experience of street children with scabies in the global south. This study explored perceived susceptibility to scabies and related lived experiences of street children in Addis Ababa. Using in-depth interviews, we collected qualitative data from selected children of the street to identify their understanding of the causes of scabies, their experiences of managing the condition, and their health-seeking behavior. Informants were recruited to include maximum variation in terms of age, sex, and experience of infestation. The study showed that scabies was common among street children and that the infestation has physical, psychological and social impacts. Study participants believed that scabies had its origin in their living conditions (including poor environmental sanitation and lack of personal hygiene), with lice playing a significant role as vectors of transmission. The informants reported visiting modern healthcare facilities, traditional healers and self-care in response to infestation. By uncovering the embodied experience of a stigmatized skin NTD in a neglected community in the global south, this study contributes to combating neglect and addressing health disparities. Having identified living conditions as the major factor contributing to susceptibility, efforts need to be exerted to change street children's living situations and other structural conditions through reunification with their families or other communities, reintegration and other exit strategies.
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