RESUMO
The single onchocerciasis-endemic focus in the remote Amazon rainforest is shared by Brazil and Venezuela and affects primarily the indigenous Yanomami people. Regional elimination of onchocerciasis is challenged by the magnitude and inaccessibility of this area. In Brazil, 272 onchocerciasis-endemic communities are operationally organized through 21 health centers ("polos bases"). Mass drug administration of ivermectin began in 1995, with 36 effective biannual rounds (≥85% coverage of the eligible population) through 2022. The national on chocerciasis program maintains community-level monitoring to prioritize treatment activities and epidemiological surveys. The Onchocerciasis Elimination Program for the Americas and the WHO onchocerciasis elimination guidelines have helped Brazil move toward its goal of stopping ivermectin treatment by 2025 and verifying transmission elimination by 2030. Additional challenges to the Brazilian onchocerciasis program include cross-border movements and insecurity due to illegal mining and inter-community conflicts. The new government in Brazil offers hope given its commitment to the equity of indigenous people and preservation of the Amazon environment.
Assuntos
Erradicação de Doenças , Ivermectina , Oncocercose , Humanos , Brasil/epidemiologia , Oncocercose/prevenção & controle , Oncocercose/epidemiologia , Oncocercose/tratamento farmacológico , Erradicação de Doenças/métodos , Ivermectina/uso terapêutico , Administração Massiva de Medicamentos , Filaricidas/uso terapêuticoRESUMO
In the Americas, onchocerciasis has been eliminated in 11 of 13 endemic foci by mass administration of ivermectin. The remaining at-risk population resides in a contiguous cross-border transmission zone located in the Amazon jungle in northwest Brazil and southern Venezuela, known as the Yanomami Focus Area. Here, we describe the development and implementation of a data-driven tool, called the Scorecard Approach (SCA), for the 393 communities that comprise the Venezuela South Focus. The SCA was first applied in 2018 and is reassessed on an annual basis. This operational strategy seeks to prioritize communities with low ivermectin coverage while taking into account the nature and variation of other epidemiological and logistical variables. Numeric scores are assigned for each factor and added together to yield a composite score for each community that is categorized as high, medium, or low priority. In this way, the SCA serves as a valuable and comprehensive strategy for planning, monitoring, and maximizing programmatic efficiency. In addition, it has allowed the country to face the main challenges of this endemic area: its remoteness, its large areas of territory to cover, the semi-nomadic nature of the Yanomami people, and their continuous cross-border movements. For 2022, the SCA categorized 54 (13.7%), 108 (27.5%), and 231 (58.8%) communities as high, medium, and low priority, respectively. The results presented here show that prioritizing communities at risk and with greatest needs increases the feasibility of interrupting the transmission of onchocerciasis by 2025 in the last endemic focus in the Americas.
Assuntos
Ivermectina , Oncocercose , Venezuela/epidemiologia , Oncocercose/prevenção & controle , Oncocercose/epidemiologia , Oncocercose/transmissão , Oncocercose/tratamento farmacológico , Humanos , Ivermectina/uso terapêutico , Erradicação de Doenças/métodos , Administração Massiva de MedicamentosRESUMO
BACKGROUND: All formerly endemic communities of the Southern Chiapas focus of onchocerciasis in Mexico were treated with ivermectin until parasite transmission was eliminated by 2015. Transmission of onchocerciasis did not resume during a period of three years (2012-2014) following the final distribution of ivermectin in 2011; it was thus concluded that transmission remained undetectable without intervention. WHO thus declared the elimination of transmission of onchocerciasis from Mexico in 2015. METHODOLOGY/PRINCIPAL FINDINGS: From 2016 to the present, post-elimination surveillance (PES) based on examination for suspected onchocercomas was performed in the former Southern Chiapas focus. Each year, over 60% of the total population (range = 85,347-104,106 individuals) of the formerly endemic communities were examined for onchocercomas. Thirty-four individuals were found harboring suspected onchocercomas in the PES surveys conducted from 2016-2019. Of these, one female of 7 years of age who had immigrated from a formerly endemic focus, harbored an infertile (sterile) female in the suspected onchocercoma; all others were negative. Skin biopsy assessments were performed from March through May 2017 in three communities where the female resided. None of the 83 individuals of the three communities examined by skin biopsy were mf positive. Similarly, none of the biopsies from the individuals were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA). CONCLUSIONS/SIGNIFICANCE: These provide support to the conclusion that onchocerciasis has been eliminated from Mexico.
Assuntos
Ivermectina/uso terapêutico , Onchocerca volvulus , Oncocercose/tratamento farmacológico , Oncocercose/epidemiologia , Vigilância da População , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , DNA de Helmintos/genética , Erradicação de Doenças , Feminino , Humanos , Lactente , Ivermectina/administração & dosagem , Masculino , Administração Massiva de Medicamentos , México/epidemiologia , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , Pele/parasitologia , Adulto JovemRESUMO
ABSTRACT Background: Studies related to infectivity status of insect vectors are seen as necessities in understanding the epidemiology of vector-borne diseases and planning effective control measures. This study assessed the infectivity ofSimulium damnosum s.l. around Owena River as well as evaluated therapeutic coverage of Ivermectin distribution in the area. Method: Human landing sampling method was used to collect adult flies on human attractants from 07:00 to 18:00 for two consecutive days a month for three months (July 2016 - September 2016). Parity assessment was conducted to determine the age of fly populations. Parous flies were further dissected to detect the presence or absence ofOnchocerca larvae. Biting rates and transmission potentials were calculated using standard methods. A quantitative survey was carried out to determine the therapeutic coverage and compliance to ivermectin treatment for the control of Onchocerciasis in the study area using standard household coverage questionnaires. Results: A total of 914 adult female flies were collected during the study period. The daily biting rate (DBR) varied from 146 fly per man day (FMD) in July to 162.5 FMD in August. The monthly biting rate (MBR) was lowest in September (2170 bites per man per month) but highest in August (3358.3 bites per man per month). MBD ranged from 13.23 fly per man hour (FMH) in July to 14.77 FMH in August. The results indicated that the majority of the flies collected at the sampling points were nulliparous [685 (74.95%)] while others were parous [229 (25.05%)]. The biting activity of the flies showed a marked decrease in population in August compared to July which later increased in September. Infection rates varied from 2 (0.7%) in July to 7 (2.2%) in August while the infectivity rate during the study ranged from zero (July and September) to 3 (1.0%) in August. Conclusion: Despite the years of treatment of onchocerciasis in Owena community, there were still some infective flies capable of transmitting O. volvolus. This could be due to the low rate of therapeutic coverage as a result of non-compliance in the community for various reasons earlier stated.
Assuntos
Humanos , Animais , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Oncocercose/tratamento farmacológico , Oncocercose/transmissão , Simuliidae/parasitologia , Ivermectina/uso terapêutico , Mordeduras e Picadas de Insetos/tratamento farmacológico , Antiparasitários/uso terapêutico , Oncocercose/parasitologia , Rios , Mordeduras e Picadas de Insetos/parasitologia , Mordeduras e Picadas de Insetos/epidemiologia , Insetos Vetores/parasitologia , Nigéria/epidemiologiaRESUMO
BACKGROUND: Studies related to infectivity status of insect vectors are seen as necessities in understanding the epidemiology of vector-borne diseases and planning effective control measures. This study assessed the infectivity ofSimulium damnosum s.l. around Owena River as well as evaluated therapeutic coverage of Ivermectin distribution in the area. METHOD: Human landing sampling method was used to collect adult flies on human attractants from 07:00 to 18:00 for two consecutive days a month for three months (July 2016 - September 2016). Parity assessment was conducted to determine the age of fly populations. Parous flies were further dissected to detect the presence or absence ofOnchocerca larvae. Biting rates and transmission potentials were calculated using standard methods. A quantitative survey was carried out to determine the therapeutic coverage and compliance to ivermectin treatment for the control of Onchocerciasis in the study area using standard household coverage questionnaires. RESULTS: A total of 914 adult female flies were collected during the study period. The daily biting rate (DBR) varied from 146 fly per man day (FMD) in July to 162.5 FMD in August. The monthly biting rate (MBR) was lowest in September (2170 bites per man per month) but highest in August (3358.3 bites per man per month). MBD ranged from 13.23 fly per man hour (FMH) in July to 14.77 FMH in August. The results indicated that the majority of the flies collected at the sampling points were nulliparous [685 (74.95%)] while others were parous [229 (25.05%)]. The biting activity of the flies showed a marked decrease in population in August compared to July which later increased in September. Infection rates varied from 2 (0.7%) in July to 7 (2.2%) in August while the infectivity rate during the study ranged from zero (July and September) to 3 (1.0%) in August. CONCLUSION: Despite the years of treatment of onchocerciasis in Owena community, there were still some infective flies capable of transmitting O. volvolus. This could be due to the low rate of therapeutic coverage as a result of non-compliance in the community for various reasons earlier stated.
Assuntos
Antiparasitários/uso terapêutico , Mordeduras e Picadas de Insetos/tratamento farmacológico , Ivermectina/uso terapêutico , Oncocercose/tratamento farmacológico , Oncocercose/transmissão , Simuliidae/parasitologia , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , Feminino , Humanos , Mordeduras e Picadas de Insetos/epidemiologia , Mordeduras e Picadas de Insetos/parasitologia , Insetos Vetores/parasitologia , Masculino , Pessoa de Meia-Idade , Nigéria/epidemiologia , Oncocercose/parasitologia , Rios , Adulto JovemRESUMO
The Onchocerciasis Elimination Program for the Americas (OEPA) is a regional initiative and international partnership that has made considerable progress toward its goal since it was launched in 1993. Its strategy is based on mass drug administration of ivermectin (Mectizan, donated by MSD, also known as Merck & Co., Inc., Kenilworth, NJ, USA), twice or four times per year, with at least 85% coverage of eligible populations. From 1989 to 2016, 11 741 276 ivermectin treatments have been given in the Americas, eliminating transmission in 11 of 13 foci. The OEPA's success has had a great influence on programs in Africa, especially Sudan and Uganda, which moved from a control to an elimination strategy in 2006 and 2007, respectively. The successes in the Americas have also greatly influenced WHO guidelines for onchocerciasis transmission elimination. With four of the six originally endemic American countries now WHO verified as having eliminated onchocerciasis transmission, and 95% of ivermectin treatments in the region halted, the regional focus is now on the remaining active transmission zone, called the Yanomami Area, on the border between Venezuela and Brazil. Both countries have difficult political climates that hinder the elimination task in this remote and relatively neglected region. As with other elimination efforts, 'the final inch' is often the most difficult task of all.
Assuntos
Antiparasitários/uso terapêutico , Erradicação de Doenças/organização & administração , Ivermectina/uso terapêutico , Oncocercose/tratamento farmacológico , Oncocercose/prevenção & controle , Antiparasitários/provisão & distribuição , Humanos , Ivermectina/provisão & distribuição , América do Sul , Estados UnidosRESUMO
The study of neglected diseases has not received much attention, especially from public and private institutions over the last years, in terms of strong support for developing treatment for these diseases. Support in the form of substantial amounts of private and public investment is greatly needed in this area. Due to the lack of novel drugs for these diseases, nanobiotechnology has appeared as an important new breakthrough for the treatment of neglected diseases. Recently, very few reviews focusing on filiarasis, leishmaniasis, leprosy, malaria, onchocerciasis, schistosomiasis, trypanosomiasis, and tuberculosis, and dengue virus have been published. New developments in nanocarriers have made promising advances in the treatment of several kinds of diseases with less toxicity, high efficacy and improved bioavailability of drugs with extended release and fewer applications. This review deals with the current status of nanobiotechnology in the treatment of neglected diseases and highlights how it provides key tools for exploring new perspectives in the treatment of a wide range of diseases.
Assuntos
Portadores de Fármacos/uso terapêutico , Nanopartículas/uso terapêutico , Doenças Negligenciadas/tratamento farmacológico , Medicina Tropical , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/efeitos adversos , Portadores de Fármacos/farmacocinética , Humanos , Leishmaniose/tratamento farmacológico , Hanseníase/tratamento farmacológico , Lipossomos/farmacocinética , Lipossomos/uso terapêutico , Malária/tratamento farmacológico , Nanopartículas/administração & dosagem , Nanopartículas/efeitos adversos , Oncocercose/tratamento farmacológico , Esquistossomose/tratamento farmacológico , Tripanossomíase/tratamento farmacológico , Tuberculose/tratamento farmacológicoRESUMO
INTRODUCTION: Onchocerca volvulus infects in excess of 15 million people. The vectors are Simulium blackflies, varieties of which differ in their ecologies, behavior and vectorial abilities. Control of the vectors and mass administrations of ivermectin have succeeded in reducing prevalences with elimination achieved in some foci, particularly in Central and southern America. In Africa, progress towards elimination has been less successful. Areas covered: Even with community directed treatment with ivermectin (CDTI), control has been difficult in African areas with initial prevalences in excess of 55%, especially if only annual treatments are dispensed. This is partly attributable to insufficient coverage, but the appearance of incipiently resistant non-responding parasites and lack of attention to vector biology in modeling and planning outcomes of intervention programmes have also played their parts, with recrudescence now appearing in some treated areas. Expert commentary: The biology of onchocerciasis is complex involving different vectors with differing abilities to transmit parasites, diverse pathologies related to geographical and parasite variations and endosymbionts in both parasite and vector. Modeling to predict epidemiological and control outcomes is addressing this complexity but more attention needs to be given to the vectors' roles to further understanding of where and when control measures will succeed.
Assuntos
Albendazol/uso terapêutico , Anti-Helmínticos/uso terapêutico , Insetos Vetores/parasitologia , Oncocercose/transmissão , Simuliidae/parasitologia , África/epidemiologia , Animais , América Central/epidemiologia , Doxiciclina , Humanos , Inseticidas , Ivermectina , Macrolídeos , Onchocerca volvulus/efeitos dos fármacos , Onchocerca volvulus/crescimento & desenvolvimento , Onchocerca volvulus/patogenicidade , Oncocercose/tratamento farmacológico , Oncocercose/epidemiologia , Oncocercose/parasitologia , América do Sul/epidemiologiaRESUMO
BACKGROUND: The African Programme for Onchocerciasis Control has proposed provisional thresholds for the prevalence of microfilariae in humans and of L3 larvae in blackflies, below which mass drug administration (MDA) with ivermectin can be stopped and surveillance started. Skin snips are currently the gold standard test for detecting patent Onchocerca volvulus infection, and the World Health Organization recommends their use to monitor progress of treatment programmes (but not to verify elimination). However, if they are used (in transition and in parallel to Ov-16 serology), sampling protocols should be designed to demonstrate that programmatic goals have been reached. The sensitivity of skin snips is key to the design of such protocols. METHODS: We develop a mathematical model for the number of microfilariae in a skin snip and parameterise it using data from Guatemala, Venezuela, Ghana and Cameroon collected before the start of ivermectin treatment programmes. We use the model to estimate sensitivity as a function of time since last treatment, number of snips taken, microfilarial aggregation and female worm fertility after exposure to 10 annual rounds of ivermectin treatment. RESULTS: The sensitivity of the skin snip method increases with time after treatment, with most of the increase occurring between 0 and 5 years. One year after the last treatment, the sensitivity of two skin snips taken from an individual infected with a single fertile female worm is 31 % if there is no permanent effect of multiple ivermectin treatments on fertility; 18 % if there is a 7 % reduction per treatment, and 0.6 % if there is a 35 % reduction. At 5 years, the corresponding sensitivities are 76 %, 62 % and 4.7 %. The sensitivity improves significantly if 4 skin snips are taken: in the absence of a permanent effect of ivermectin, the sensitivity of 4 skin snips is 53 % 1 year and 94 % 5 years after the last treatment. CONCLUSIONS: Our model supports the timelines proposed by APOC for post-MDA follow-up and surveillance surveys every 3-5 years. Two skin snips from the iliac region have reasonable sensitivity to detect residual infection, but the sensitivity can be significantly improved by taking 4 snips. The costs and benefits of using four versus two snips should be evaluated.
Assuntos
Doenças Negligenciadas/diagnóstico , Doenças Negligenciadas/parasitologia , Onchocerca volvulus/isolamento & purificação , Oncocercose/diagnóstico , Oncocercose/parasitologia , Pele/parasitologia , Animais , Camarões/epidemiologia , Feminino , Gana/epidemiologia , Guatemala/epidemiologia , Humanos , Ivermectina/uso terapêutico , Doenças Negligenciadas/tratamento farmacológico , Doenças Negligenciadas/epidemiologia , Oncocercose/tratamento farmacológico , Oncocercose/epidemiologia , Vigilância da População , Sensibilidade e Especificidade , Venezuela/epidemiologiaRESUMO
OBJECTIVES: To evaluate the effect of ivermectin mass drug administration on strongyloidiasis and other soil transmitted helminthiases. METHODS: We conducted a retrospective analysis of data collected in Esmeraldas (Ecuador) during surveys conducted in areas where ivermectin was annually administered to the entire population for the control of onchocerciasis. Data from 5 surveys, conducted between 1990 (before the start of the distribution of ivermectin) and 2013 (six years after the interruption of the intervention) were analyzed. The surveys also comprised areas where ivermectin was not distributed because onchocerciasis was not endemic. Different laboratory techniques were used in the different surveys (direct fecal smear, formol-ether concentration, IFAT and IVD ELISA for Strongyloides stercoralis). RESULTS: In the areas where ivermectin was distributed the strongyloidiasis prevalence fell from 6.8% in 1990 to zero in 1996 and 1999. In 2013 prevalence in children was zero with stool examination and 1.3% with serology, in adult 0.7% and 2.7%. In areas not covered by ivermectin distribution the prevalence was 23.5% and 16.1% in 1996 and 1999, respectively. In 2013 the prevalence was 0.6% with fecal exam and 9.3% with serology in children and 2.3% and 17.9% in adults. Regarding other soil transmitted helminthiases: in areas where ivermectin was distributed the prevalence of T. trichiura was significantly reduced, while A. lumbricoides and hookworms were seemingly unaffected. CONCLUSIONS: Periodic mass distribution of ivermectin had a significant impact on the prevalence of strongyloidiasis, less on trichuriasis and apparently no effect on ascariasis and hookworm infections.