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dc.contributor.authorHernández-González, Ana 
dc.contributor.authorMoya, Laura 
dc.contributor.authorPerteguer-Prieto, Maria Jesus 
dc.contributor.authorHerrador, Zaida 
dc.contributor.authorNguema, Rufino
dc.contributor.authorNguema, Justino
dc.contributor.authorAparicio, Pilar 
dc.contributor.authorBenito, Agustin 
dc.contributor.authorGarate, Teresa
dc.identifier.citationParasit Vectors. 2016; 9(1): 509
dc.description.abstractBACKGROUND: Onchocerciasis or "river blindness" is a chronic parasitic disease caused by the filarial worm Onchocerca volvulus, transmitted through infected blackflies (Simulium spp.). Bioko Island (Equatorial Guinea) used to show a high endemicity for onchocerciasis. During the last years, the disease control programmes using different larvicides and ivermectin administration have considerably reduced the prevalence and intensity of infection. Based on this new epidemiological scenario, in the present work we aimed to assess the impact of the strategies applied against onchocerciasis in Bioko Island by an evaluation of IgG4 antibodies specific for recombinant Ov-16 in ELISA. METHODS: A cross-sectional study was conducted in Bioko Island from mid-January to mid-February, 2014. Twenty communities were randomly selected from rural and urban settings. A total of 140 households were chosen. In every selected household, all individuals aged 5 years and above were recruited; 544 study participants agreed to be part of this work. No previous data on onchocerciasis seroprevalence in the selected communities were available. Blood samples were collected and used in an "ELISA in-house" prepared with recombinant Ov-16, expressed and further purified. IgG4 antibodies specific for recombinant Ov-16 were evaluated by ELISA in all of the participants. RESULTS: Based on the Ov-16 ELISA, the onchocerciasis seroprevalence was 7.9 %, mainly concentrated in rural settings; samples from community Catedral Ela Nguema (# 16) were missed during the field work. Among the rural setups, communities Inasa Maule (# 7), Ruiché (# 20) and Barrios Adyacentes Riaba (# 14), had the highest seropositivity percentages (29.2, 26.9 and 23.8 %, respectively). With respect to the urban settings, we did not find any positive case in communities Manzana Casa Bola (# 3), Colas Sesgas (# 6), Getesa (# 8), Moka Bioko (# 9), Impecsa (# 10), Baney Zona Baja (# 12) and Santo Tomás de Aquino (# 1). No onchocerciasis seropositive samples were found in 10-year-old individuals or younger. The IgG4 positive titles increased in older participants. CONCLUSIONS: A significant decline in onchocerciasis prevalence was observed in Bioko Island after years of disease-vector control and CDTI strategy. The seroprevalence increased with age, mainly in rural settings that could be due to previous exposure of population to the filarial parasite, eliminated by the control programmes introduced against onchocerciasis. A new Ov-16 serological evaluation with a larger sample size of children below 10 years of age is required to demonstrate the interruption of transmission of O. volvulus in the human population of Bioko Island (Equatorial Guinea) according to the WHO criteria.
dc.description.sponsorshipWe would like to thank the National Program for Control of Onchocerciasis and other Filariasis in Equatorial Guinea for supporting us to obtain the information on which this study is based. We are grateful to the study participants for volunteering to participate in the study and the data collectors for performing field work. Our gratitude to the Unit of Serological Diagnosis, Department of Parasitology, Centro Nacional de Microbiología, and the Spanish Red Cross for providing some control samples. Thanks are also due to Diana Gomez-Barroso, from the National Centre of Epidemiology (ISCIII) for her help with the mapping.
dc.publisherBioMed Central
dc.relation.isversionofPublisher's version
dc.subjectOnchocerca volvulus
dc.subjectBioko Island
dc.subjectEquatorial Guinea
dc.subjectOv-16/IgG4 ELISA
dc.titleEvaluation of onchocerciasis seroprevalence in Bioko Island (Equatorial Guinea) after years of disease control programmes
dc.rights.licenseAtribución 4.0 Internacional*
dc.contributor.funderRed de Investigación Colaborativa en Enfermedades Tropicales
dc.contributor.funderSpanish Agency for International Development Cooperation
dc.identifier.journalParasites and Vectors
dc.repisalud.centroISCIII::Centro Nacional de Microbiología
dc.repisalud.centroISCIII::Centro Nacional de Medicina Tropical

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