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2.
BMC Infect Dis ; 20(1): 726, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33008333

RESUMO

BACKGROUND: Ivermectin is an excellent microfilaricide against Onchocerca volvulus. However, in some regions, long term use of ivermectin has resulted in sub-optimal responses to the treatment. More data to properly document the phenomenon in various contexts of ivermectin mass drug administration (IVM-MDA) is needed. Also, there is a need to accurately monitor a possible repopulation of skin by microfilariae following treatment. Skin snip microscopy is known to have a low sensitivity in individuals with light infections, which can be the case following treatment. This study was designed with two complementary objectives: (i) to assess the susceptibility of O. volvulus microfilariae to ivermectin in two areas undergoing IVM-MDA for different lengths of time, and (ii) to document the repopulation of skin by the O. volvulus microfilariae following treatment, using 3 independent diagnostic techniques. METHOD: Identified microfilaridermic individuals were treated with ivermectin and re-examined after 1, 3, and 6 months using microscopy, actin real-time PCR (actin-qPCR) and O-150 LAMP assays. Susceptibility to ivermectin and trends in detecting reappearance of skin microfilariae were determined using three techniques. Microscopy was used as an imperfect gold standard to determine the performance of actin-qPCR and LAMP. RESULTS: In Bafia with over 20 years of IVM-MDA, 11/51 (21.6%) direct observe treated microfilaridemic participants were still positive for skin microfilariae after 1 month. In Melong, with 10 years of IVM-MDA, 2/29 (6.9%) treated participants were still positive. The microfilarial density reduction per skin biopsy within one month following treatment was significantly lower in participants from Bafia. In both study sites, the molecular techniques detected higher proportions of infected individuals than microscopy at all monitoring time points. LAMP demonstrated the highest levels of sensitivity and real-time PCR was found to have the highest specificity. CONCLUSION: Patterns in skin mirofilariae clearance and repopulation were established. O. volvulus worms from Bafia with higher number of annual MDA displayed a lower clearance and higher repopulation rate after treatment with ivermectin. Molecular assays displayed higher sensitivity in monitoring O. volvulus microfilaridemia within six months following treatment.


Assuntos
Antiparasitários/uso terapêutico , Ivermectina/uso terapêutico , Onchocerca volvulus/fisiologia , Oncocercose/tratamento farmacológico , Pele/patologia , Adolescente , Animais , Biópsia , Camarões , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Administração Massiva de Medicamentos , Microscopia , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem
4.
PLoS Negl Trop Dis ; 14(9): e0008642, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32976514

RESUMO

Mass Drug Administration (MDA) programs to eliminate Lymphatic Filariasis (LF) in western Africa use the anthelminthics ivermectin plus albendazole. These drugs have the potential to impact also Soil-Transmitted Helminth (STH) infections, since the drugs have a broad range of anthelminthic activity. Integration of preventive chemotherapy efforts for LF, onchocerciasis and STH is recommended by the World Health Organization (WHO) in order to avoid duplication of MDA and to reduce costs. The objective of the current study was to determine whether five semi-annual rounds of community-wide MDA to eliminate LF and onchocerciasis have a greater impact on STH than three annual rounds of MDA with similar compliance. The effects of MDA using ivermectin (IVM, 0.2 mg/kg) combined with albendazole (ALB, 400 mg) on the prevalence and intensity of hookworm infection were evaluated in the Abengourou (annual MDA) and Akoupé (semi-annual MDA) health Districts in eastern Côte d'Ivoire from 2014 to 2017. A cross-sectional approach was used together with mixed logistic regression, and mixed linear models. Subjects were tested for STH using the Kato-Katz technique before the first round of MDA and 12, 24, and 36 months after the first round of MDA. The mean self-reported MDA compliance assessed during the survey was 65%, and no difference was observed between treatment areas. These results were confirmed by an independent coverage survey as recommended by WHO. Hookworm was the most prevalent STH species in both areas (23.9% vs 12.4%) and the prevalence of other STH species was less than 1%. The crude prevalence of hookworm dropped significantly, from 23.9% to 5.5% (p <0.001, 77% reduction) in the annual MDA treatment area and from 12.4% to 1.9% (p <0.001, 85% reduction) in the semi-annual treatment area. The average intensity of hookworm infection decreased in the annual MDA area (406.2 epg to 118.3 epg), but not in the semi-annual MDA area (804.9 epg to 875.0 epg). Moderate and heavy infections (1% and 1.3% at baseline) were reduced to 0% and 0.4% in the annual and semi-annual treatment areas, respectively. Using a mixed logistic regression model, and after adjusting for baseline prevalence, only the year 2 re-examination showed a difference in prevalence between treatments (OR: 2.26 [95% CI: 1.03, 4.98], p = 0.043). Analysis of intensity of hookworm infection indicated also that treatment differences varied by follow-up visit. In conclusion twelve months after the last treatment cycle, three annual and five semi-annual rounds of community-wide MDA with the combination of IVM and ALB showed strong, but similar impact on hookworm prevalence and intensity in eastern Côte d'Ivoire. Therefore, an annual MDA regimen seems to be an efficient strategy to control hookworm infection in endemic areas with low and moderate infection prevalence. Trial registration: The study was registered at ClinicalTrial.gov under the number NTC02032043.


Assuntos
Filariose Linfática/tratamento farmacológico , Infecções por Uncinaria/tratamento farmacológico , Administração Massiva de Medicamentos/métodos , Oncocercose/tratamento farmacológico , Adolescente , Adulto , Albendazol/administração & dosagem , Albendazol/uso terapêutico , Ancylostomatoidea , Animais , Criança , Costa do Marfim/epidemiologia , Estudos Transversais , Combinação de Medicamentos , Filariose Linfática/epidemiologia , Feminino , Infecções por Uncinaria/epidemiologia , Humanos , Ivermectina/administração & dosagem , Ivermectina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Oncocercose/epidemiologia , Prevalência , Adulto Jovem
5.
Am J Trop Med Hyg ; 103(4): 1563-1568, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32748783

RESUMO

Human landing collections (HLCs) have been the standard method for the collection of black flies that serve as vectors for Onchocerca volvulus, the causative agent of onchocerciasis or river blindness. However, HLCs are inefficient and may expose collectors to vector-borne pathogens. The Esperanza window trap (EWT) has been shown to be a potential alternative to HLCs for the collection of Simulium damnosum, the principal vector of O. volvulus in Africa. To improve the performance of the EWT, sweat from individuals highly attractive or less attractive to S. damnosum sensu stricto was examined by gas chromatography and mass spectroscopy. Twelve compounds were identified which were solely present or present in increased amounts in the sweat of the highly attractive individuals. Two of these compounds (naphthalene and tert-hexadecyl mercaptan) were found to be attractive to S. damnosum s.s. in behavioral assays. Traps baited with these compounds outperformed those baited with the current standard bait of worn socks. Using these newly identified compounds as baits will make the EWT more efficient in collecting vector black flies and may enhance the potential utility of the EWT as a local vector control measure.


Assuntos
Insetos Vetores/parasitologia , Onchocerca volvulus/fisiologia , Oncocercose/transmissão , Simuliidae/parasitologia , Animais , Feminino , Humanos , Oncocercose/epidemiologia , Oncocercose/parasitologia , Suor/parasitologia , Uganda/epidemiologia
6.
Am J Trop Med Hyg ; 103(4): 1556-1562, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32748784

RESUMO

In the United States and Europe, human onchocerciasis is a rare disease caused by zoonotic or anthropophilic parasites in the genus Onchocerca. The zoonotic species identified in focal areas of Europe and United States is Onchocerca lupi, and Onchocerca volvulus, the anthroponotic species, may be found among people who had lived in endemic areas of Africa, the Arabian Peninsula, or Latin America. Onchocerciasis due to O. lupi is an emergent parasitic disease, with limited diagnostic methods, in addition to the lack of information on its biology, transmission, and epidemiology. Cutaneous nodules are the disease's most prevalent manifestation but lack diagnostic specificity. To address the diagnosis of onchocerciasis at reference laboratories, we developed a duplex TaqMan real-time PCR (qPCR) method, targeting the cytochrome oxidase subunit I locus which has species-specific probes to identify and differentiate O. lupi from O. volvulus. We determined the performance of the duplex with a panel of 45 samples: 11 positives for O. lupi, six for O. volvulus, five samples with negative results for Onchocerca spp., and 23 non-Onchocerca nematodes. The duplex qPCR correctly detected 10 of 11 O. lupi- and six of six O. volvulus-positive specimens. The new duplex assay allowed the simultaneous detection and discrimination of O. lupi and O. volvulus in clinical specimens, expediting and facilitating the clinical diagnosis of O. lupi in non-endemic settings where the disease is an infrequent finding.


Assuntos
Doenças do Cão/parasitologia , Onchocerca volvulus/isolamento & purificação , Onchocerca/isolamento & purificação , Oncocercose/parasitologia , Animais , Diagnóstico Diferencial , Cães , Humanos , Onchocerca/genética , Onchocerca volvulus/genética , Oncocercose/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Especificidade da Espécie , Zoonoses
7.
Am J Trop Med Hyg ; 103(4): 1569-1571, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32840200

RESUMO

Onchocerciasis is a blinding disease caused by the filarial parasite Onchocerca volvulus, with a worldwide distribution. Onchocerciasis has been targeted for regional elimination based on annual and semiannual mass drug administration (MDA) with ivermectin in endemic communities over several years. This strategy in Ecuador led to the interruption of transmission and suspension of ivermectin MDA in 2009 with certification of elimination in 2014. In the present study, we analyzed sera collected in 2018 from 123 children aged 5-9 years from formerly hyperendemic communities in the Esmeraldas focus, Ecuador, for the presence of antibodies to Ov16 antigen. All samples were negative, indicating no evidence of transmission since MDA was stopped. Ov16-based serology offers an economic and practical alternative for measuring vector infectivity for post-certification surveillance in formerly endemic countries where expertise and capacity to reliably measure fly infectivity rates are costly to maintain.


Assuntos
Onchocerca volvulus/imunologia , Oncocercose/epidemiologia , Animais , Criança , Pré-Escolar , Erradicação de Doenças , Equador/epidemiologia , Doenças Endêmicas , Monitoramento Epidemiológico , Feminino , Humanos , Masculino , Onchocerca volvulus/isolamento & purificação , Oncocercose/parasitologia , Oncocercose/prevenção & controle
8.
BMC Public Health ; 20(1): 1233, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32787813

RESUMO

BACKGROUND: Control and elimination of onchocerciasis requires regular follow-up and evaluation of community directed treatment with ivermectin (CDTi) program implementation. This research was aimed to assess the epidemiological status of onchocerciasis in disease endemic communities of Asosa and Yeki districts of Ethiopia after 5 and 15 years of successive CDTi respectively, and to evaluate the decline in infection and morbidity burden. METHODS: A community-based cross-sectional study was conducted from August 2017 to January 2018 (i.e. within 2-7 months since the last treatment) using interview, physical and parasitological examinations. Pre-CDTi epidemiological data were obtained from studies conducted prior to the launch of CDTi. RESULTS: A total of 3002 individuals (1567 from Asosa and 1435 from Yeki) were included. No infection was detected from Yeki. In Asosa, the prevalence of infection was 1.6%. The geometric mean intensity of infection was 0.02 mf/mg of skin snip. The prevalence rates of dermatitis, depigmentation, nodule, and atrophy in Yeki were 33(2.3%), 57(4%), 37(2.6%) and 11(0.7%), respectively. The prevalence rates of papular dermatitis, depigmentation, palpable nodule, atrophy, and blindness in Asosa were 94(6%), 38(2.4%), 30(1.9%), 28(1.8%) and 2(0.1%), respectively. Five years of CDTi had significantly reduced prevalence and intensity of infection by 91.8% (p < 0.001) and 99.7% (p < 0.001), respectively. Moreover, CDTi reduced prevalence of papular dermatitis by 95.9% (p < 0.001), palpable nodule by 90.5% (p < 0.001), and atrophy by 30% (p = 0.6) in Yeki. Similarly, CDTi reduced prevalence of papular dermatitis by 88.6% (p < 0.001), depigmentation by 90.3% (p < 0.001), atrophy by 89.5% (p < 0.001), and blindness by 90% (p < 0.001) in Asosa. CONCLUSIONS: Fifteen years of successive CDTi had brought the infection from high to zero in Yeki. However, thorough entomological and serological data need to be generated to ascertain whether complete interruption of parasite transmission has been attained, and for considerations of an evidence-based CDTi cessation. Five years of CDTi in Asosa has significantly reduced the infection and morbidity of onchocerciasis to very low level. We, hereby, recommend biannual CDTi to continue in Asosa and its surroundings until the infection transmission is fully interrupted.


Assuntos
Doenças Endêmicas/prevenção & controle , Ivermectina/uso terapêutico , Administração Massiva de Medicamentos , Oncocercose/tratamento farmacológico , Oncocercose/epidemiologia , Adolescente , Adulto , Estudos Transversais , Etiópia/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Morbidade , Prevalência , Avaliação de Programas e Projetos de Saúde , Adulto Jovem
9.
PLoS Negl Trop Dis ; 14(7): e0008427, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32628671

RESUMO

A major impediment to eliminate lymphatic filariasis and onchocerciasis is the lack of effective short-course macrofilaricidal drugs or regimens that are proven to be safe for both infections. In this study we tested oxfendazole, an anthelmintic shown to be well tolerated in phase 1 clinical trials. In vitro, oxfendazole exhibited modest to marginal motility inhibition of adult worms of Onchocerca gutturosa, pre-adult worms of Onchocerca volvulus and Onchocerca lienalis microfilariae. In vivo, five days of oral treatments provided sterile cure with up to 100% macrofilaricidal efficacy in the murine Litomosoides sigmodontis model of filariasis. In addition, 10 days of oral treatments with oxfendazole inhibited filarial embryogenesis in patent L. sigmodontis-infected jirds and subsequently led to a protracted but complete clearance of microfilaremia. The macrofilaricidal effect observed in vivo was selective, as treatment with oxfendazole of microfilariae-injected naïve mice was ineffective. Based on pharmacokinetic analysis, the driver of efficacy is the maintenance of a minimal efficacious concentration of approximately 100 ng/ml (based on subcutaneous treatment at 25 mg/kg in mice). From animal models, the human efficacious dose is predicted to range from 1.5 to 4.1 mg/kg. Such a dose has already been proven to be safe in phase 1 clinical trials. Oxfendazole therefore has potential to be efficacious for treatment of human filariasis without causing adverse reactions due to drug-induced microfilariae killing.


Assuntos
Benzimidazóis/farmacologia , Filariose Linfática/tratamento farmacológico , Filarioidea/efeitos dos fármacos , Animais , Anti-Helmínticos/uso terapêutico , Modelos Animais de Doenças , Filariose Linfática/parasitologia , Feminino , Filarioidea/embriologia , Gerbillinae/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Microfilárias/efeitos dos fármacos , Onchocerca/efeitos dos fármacos , Onchocerca volvulus/efeitos dos fármacos , Oncocercose/tratamento farmacológico
10.
Nat Commun ; 11(1): 2685, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483209

RESUMO

Lymphatic filariasis and onchocerciasis are neglected tropical diseases (NTDs) targeted for elimination by mass (antifilarial) drug administration. These drugs are predominantly active against the microfilarial progeny of adult worms. New drugs or combinations are needed to improve patient therapy and to enhance the effectiveness of interventions in persistent hotspots of transmission. Several therapies and regimens are currently in (pre-)clinical testing. Clinical trial simulators (CTSs) project patient outcomes to inform the design of clinical trials but have not been widely applied to NTDs, where their resource-saving payoffs could be highly beneficial. We demonstrate the utility of CTSs using our individual-based onchocerciasis transmission model (EPIONCHO-IBM) that projects trial outcomes of a hypothetical macrofilaricidal drug. We identify key design decisions that influence the power of clinical trials, including participant eligibility criteria and post-treatment follow-up times for measuring infection indicators. We discuss how CTSs help to inform target product profiles.


Assuntos
Ensaios Clínicos como Assunto/métodos , Filariose Linfática/tratamento farmacológico , Filaricidas/uso terapêutico , Oncocercose/tratamento farmacológico , Protocolos de Ensaio Clínico como Assunto , Ensaios Clínicos como Assunto/estatística & dados numéricos , Simulação por Computador , Avaliação de Medicamentos/métodos , Avaliação de Medicamentos/estatística & dados numéricos , Humanos , Ivermectina/uso terapêutico , Modelos Biológicos , Oncocercose/parasitologia , Oncocercose/transmissão
12.
Am J Trop Med Hyg ; 103(3): 1135-1142, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32588807

RESUMO

Wambabya-Rwamarongo onchocerciasis focus is one of the eight foci Uganda verified using the WHO verification guidelines. The approach for elimination was twice yearly treatment with ivermectin for every round, treating at least 90% of all the eligible population. This was in combination with vector elimination using Abate® (BASF SE, Limburgerhof, Germany) since elimination nationwide policy was launched. From 2008 to 2013, the program distributed ivermectin with a mean treatment coverage of the ultimate treatment goal (UTG) or eligible population of 91.2%, with a range of 85-96%. In 2009, vector elimination based on ground larviciding had a dramatic impact on the Simulium vectors, as the last fly was observed in October 2009. No more Simulium vectors were observed during a period of at least 7 years, including the 3-year posttreatment surveillance (PTS) until the focus was reclassified as eliminated in August 2017. During the PTS period, none of the 10,578 trapped crabs were found infested with the aquatic stages of the vector. The last infested crab was observed in March 2010, and for at least 7 years, no infested crabs were observed. Serological surveys showed that of 2,978 young children examined in 2013, only one was OV16 positive (0.0%; 95% CI: 0-0.21). In 2017, after the PTS period, all 3,079 young children examined were negative for OV16 (95% CI: 0-0.16). Therefore, entomological and serological results provided evidence that resulted in the reclassification of Wambabya-Rwamarongo focus from "transmission interrupted" to "transmission eliminated" with no possibility of recrudescence.


Assuntos
Antiparasitários/uso terapêutico , Braquiúros/parasitologia , Ivermectina/uso terapêutico , Oncocercose/epidemiologia , Simuliidae/parasitologia , Temefós/uso terapêutico , Animais , Erradicação de Doenças , Humanos , Oncocercose/parasitologia , Oncocercose/transmissão , Uganda/epidemiologia
14.
Am J Trop Med Hyg ; 103(1): 287-294, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32458796

RESUMO

Elimination of an infectious disease requires subcritical transmission, or a reproductive number less than one, and can be assessed with cross-sectional surveys conducted by neglected tropical disease programs. Here, we assess the distribution of onchocerciasis prevalence taken from surveys across sub-Saharan Africa before the initiation of ivermectin in mass drug administrations. Pre-intervention nodular palpation cross-sectional surveys were available from 15 countries in the Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN) database. We determined whether the distribution of the prevalence over communities in an area was consistent with a geometric distribution, which previous studies have suggested indicates a subcritical disease. If not, we fitted a negative binominal distribution (hypothetically supercritical) or a mixture of two distributions: geometric (hypothetically subcritical) and Poisson (hypothetically supercritical). The overall distribution of community-level onchocerciasis prevalence estimates from the ESPEN dataset from 2005 to 2014 was not consistent with a geometric distribution. By contrast, data from several countries and parts of countries were consistent with the geometric distribution, for example, some areas within Nigeria and Angola. Even if the geometric distribution suggested pre-intervention subcriticality in more localized geographical areas, our model using pooled survey data of all geographic areas suggests that the entire pre-intervention prevalence does not fit a geometric distribution. Further work will be required to confirm the significance of a geometric distribution for onchocerciasis.


Assuntos
Oncocercose/epidemiologia , África ao Sul do Saara/epidemiologia , Estudos Transversais , Erradicação de Doenças/métodos , Inquéritos Epidemiológicos , Humanos , Modelos Estatísticos , Doenças Negligenciadas/epidemiologia , Doenças Negligenciadas/prevenção & controle , Oncocercose/prevenção & controle , Oncocercose/transmissão , Prevalência
16.
Vet Parasitol ; 280: 109070, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32247934

RESUMO

Onchocerca lupi is an emerging zoonotic parasite of dogs, endemic to the southwestern USA and areas of the Old World. Currently, there are no specific serological diagnostic tests able to detect O. lupi infection. Recent literature has demonstrated that commercially available heartworm antigen tests, despite being highly sensitive, may cross-react with infections by other filarid nematodes. There is no information on potential cross-reactivity of such tests in serum of dogs infected with O. lupi. Our objective was to assess serum samples of dogs naturally-infected with O. lupi for potential cross-reactivity before and after heat-treatment using a commercial heartworm ELISA kit. We obtained serum from 23 dogs naturally-infected with O. lupi. These dogs presented with ocular disease, and were consulted to schedule either surgical removal of ocular nodules due to infection or enucleation. Samples were tested in triplicate using the DiroCHEK® Heartworm Antigen Test kit (Synbiotics Corporation, Zoetis, Kalamazoo, MI, USA) following the manufacturers' protocol pre- and post-heat-treatment. Samples were heat-treated using a dry heat block at 103 °C for 10 min and then centrifuged at 1818×g for 20 min. Out of a total of 23 dogs, 19 (82.6 %) had no antigen detected regardless of heat-treatment, three dogs tested positive before and after heat-treatment, and a single dog turned positive after heat-treatment. These three dogs that were positive before and after heat-treatment were confirmedly co-infected with Dirofilaria immitis by the veterinarians responsible for these cases, and we were unable to get the history or follow up with the dog that turned positive post-heat-treatment only. Our data suggest that O. lupi infections should not result in false-positives when using the DiroCHEK® in dog serum, before or after heat-treatment. Dogs with clinical ocular onchocercosis that test antigen-positive in DiroCHEK® are likely co-infected with D. immitis, and should be further tested, including evaluation of microfilariae in blood and diagnostic imaging. If heartworm infection is confirmed, the animals should be enrolled in the recommended treatment protocol in accordance to the guidelines of the American Heartworm Society or other local organizations.


Assuntos
Antígenos de Helmintos/sangue , Doenças do Cão/imunologia , Oncocercose/veterinária , Animais , Reações Cruzadas/imunologia , Dirofilariose/imunologia , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Masculino , Onchocerca/fisiologia , Oncocercose/imunologia , Soro/imunologia
17.
Am J Trop Med Hyg ; 102(6): 1411-1416, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32228786

RESUMO

Uganda has verified elimination of seven onchocerciasis foci since 2007 when the nationwide onchocerciasis elimination policy was launched. However, the Victoria Nile focus (which was eliminated in the early 1970s) had not been verified. The objective of this study was to verify this focus to the WHO verification guidelines and bring it in line with recently eliminated foci. Vector control with dichlorodiphenyltrichloroethane was the main intervention used at the Victoria Nile from the 1950s to the 1970s. Historical fly collection sites along River Nile were identified for recent fly collection. Relevant health workers near the sites were trained to supervise fly collection activity. With support from communities, fly collectors were identified, trained, and equipped to collect Simulium flies for at least a year. A total of 854 Simulium flies were collected and analyzed by polymerase chain reaction to detect Onchocerca volvulus DNA. The communities and their leaders provided consent for the collection of dry blood spots (DBS) from children younger than 10 years for investigation of recent exposure to the disease. A total of 2,953 DBS were collected and analyzed by OV16 ELISA to detect the presence of IgG4 antibodies recognizing the OV16 antigen. The results showed that none of the flies carried O. volvulus DNA. Similarly, all the children were OV16 negative, showing no exposure to onchocerciasis. All the flies collected were identified as Simulium adersi, which is not a known vector for O. volvulus. The results confirmed that onchocerciasis and its vector Simulium damnosum had been eliminated in the Victoria Nile focus.


Assuntos
Erradicação de Doenças , Oncocercose/epidemiologia , Animais , Criança , Humanos , Controle de Insetos , Insetos Vetores , Oncocercose/prevenção & controle , Simuliidae , Uganda/epidemiologia , Organização Mundial da Saúde
18.
Sci Rep ; 10(1): 6672, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32317658

RESUMO

Skin snip evaluation for onchocerciasis has insufficient sensitivity when skin microfilarial (mf) densities are low, such as following ivermectin treatment. Mf density is suitable for assessing microfilaricidal efficacy but only serves as an indirect indicator of macrofilaricidal activity. We assessed circulating nucleic acids from Onchocerca volvulus as an alternative to skin snips. We screened a plasma sample set of infected individuals followed up at four, 12 and 21 months after microfilaricidal (ivermectin, n = four), macrofilaricidal (doxycycline, n = nine), or combination treatment (n = five). Two parasite-derived miRNAs, cel-miR-71-5p and bma-lin-4, and O-150 repeat DNA were assessed. Highly abundant DNA repeat families identified in the O. volvulus genome were also evaluated. miRNAs were detected in two of 72 plasma samples (2.8%) and two of 47 samples (4.3%) with microfilaridermia using RT-qPCR. O-150 DNA was detected in eight (44.4%) baseline samples by qPCR and the number of positives declined post-treatment. One doxycycline-treated individual remained O-150 positive. However, only 11 (23.4%) samples with microfilaridermia were qPCR-positive. Analysis by qPCR showed novel DNA repeat families were comparatively less abundant than the O-150 repeat. Circulating parasite-derived nucleic acids are therefore insufficient as diagnostic tools or as biomarkers of treatment efficacy for O. volvulus.


Assuntos
Biomarcadores/sangue , MicroRNA Circulante/sangue , DNA/sangue , Onchocerca volvulus/fisiologia , Oncocercose/tratamento farmacológico , Oncocercose/genética , Adulto , Animais , Humanos , Masculino , Oncocercose/sangue , Parasitos/genética , Resultado do Tratamento
19.
Int Health ; 12(3): 192-202, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32141502

RESUMO

BACKGROUND: A high prevalence and incidence of epilepsy has been reported in onchocerciasis-endemic regions in Central and East Africa. There is compelling epidemiological evidence suggesting that this high burden is caused by onchocerciasis-associated epilepsy (OAE). We hypothesized that OAE had also occured in West African onchocerciasis foci. METHODS: We searched PubMed, the African Journals Online platform and grey literature for population-based epilepsy studies in West African countries. Epilepsy and onchocerciasis prevalence data were extracted. The pre-control onchocerciasis endemicity in the study sites was estimated from historical data of onchocerciasis control programmes. The prevalence of epilepsy in different sites was analysed, taking into account onchocerciasis endemicity and the duration of control. RESULTS: The pooled prevalence of epilepsy in the West African study sites was 13.14 per 1000 (95% confidence interval 11.28-15.00). Higher pre-control endemicity and a shorter duration of onchocerciasis control were both associated with increased epilepsy prevalence (p<0.001). Two studies in Ivory Coast that provided detailed descriptions of persons with epilepsy in onchocerciasis-endemic settings revealed that most of them had features of OAE (73.7% and 83.3%, respectively). CONCLUSIONS: Our findings suggest that before and during the early years of implementing onchocerciasis control in West Africa, high onchocerciasis endemicity resulted in a high prevalence of OAE and that subsequent control efforts significantly reduced the prevalence of OAE.


Assuntos
Epilepsia/epidemiologia , Epilepsia/etiologia , Oncocercose/complicações , África Oriental/epidemiologia , África Ocidental/epidemiologia , Costa do Marfim/epidemiologia , Humanos , Ivermectina/uso terapêutico , Oncocercose/tratamento farmacológico , Prevalência
20.
Infect Dis Poverty ; 9(1): 12, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32114979

RESUMO

BACKGROUND: Around 2007, a nodding syndrome (NS) epidemic appeared in onchocerciasis-endemic districts of northern Uganda, where ivermectin mass distribution had never been implemented. This study evaluated the effect of community-directed treatment with ivermectin (CDTI) and ground larviciding of rivers initiated after 2009 and 2012 respectively, on the epidemiology of NS and other forms of epilepsy (OFE) in some districts of northern Uganda. METHODS: In 2012, a population-based community survey of NS/epilepsy was carried out by the Ugandan Ministry of Health in Kitgum and Pader districts. In August 2017, we conducted a new survey in selected villages of these districts and compared our findings with the 2012 data. In addition, two villages in Moyo district (where CDTI was ongoing since 1993) served as comparative onchocerciasis-endemic sites in which larviciding had never been implemented. The comparison between 2012 and 2017 prevalence and cumulative incidence were done using the Fisher's and Pearson's Chi-square tests at 95% level of significance. RESULTS: A total of 2138 individuals in 390 households were interviewed. In the selected villages of Kitgum and Pader, there was no significant decrease in prevalence of NS and OFE between 2012 and 2017. However, the cumulative incidence of all forms of epilepsy decreased from 1165 to 130 per 100 000 persons per year (P = 0.002); that of NS decreased from 490 to 43 per 100 000 persons per year (P = 0.037); and for OFE from 675 to 87 per 100 000 persons per year (P = 0.024). The median age of affected persons (NS and OFE) shifted from 13.5 (IQR: 11.0-15.0) years in 2012 to 18.0 (IQR: 15.0-20.3) years in 2017; P <  0.001. The age-standardized prevalence of OFE in Moyo in 2017 was 4.6%, similar to 4.5% in Kitgum and Pader. CONCLUSIONS: Our findings support the growing evidence of a relationship between infection by Onchocerca volvulus and some types of childhood epilepsy, and suggest that a combination of bi-annual mass distribution of ivermectin and ground larviciding of rivers is an effective strategy to prevent NS and OFE in onchocerciasis-hyperendemic areas.


Assuntos
Epilepsia/epidemiologia , Síndrome do Cabeceio/epidemiologia , Oncocercose/prevenção & controle , Adolescente , Animais , Antiparasitários/uso terapêutico , Criança , Doenças Endêmicas , Epilepsia/parasitologia , Feminino , Humanos , Incidência , Ivermectina/uso terapêutico , Masculino , Síndrome do Cabeceio/parasitologia , Onchocerca volvulus , Oncocercose/complicações , Oncocercose/epidemiologia , Prevalência , Uganda/epidemiologia , Adulto Jovem
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