ABSTRACT
Fundamento: la oncocercosis, enfermedad de Robles, es una enfermedad parasitaria crónica causada por un gusano nematodo; la filaria Onchocerca volvulus transmitida por moscas negras de la familia Simuliidae, cuyo único hospedero definitivo es el hombre. Es la segunda causa infecciosa de ceguera en el mundo. Objetivo: describir un caso de una paciente portadora de la enfermedad con un nódulo en la rama ascendente del maxilar derecho. Caso clínico: paciente africana, femenina, que acude a consulta por presentar aumento de volumen de la mandíbula derecha de varios meses de evolución y tumoración de seis centímetros de diámetro, a nivel del ángulo y rama horizontal derecha del maxilar inferior. En la citología se diagnosticó microfilariasis. Conclusiones: el parásito se trasmitió en esta enferma, como ocurre en todos los casos, por la picadura de una mosca del género Simulium, que al succionar la sangre de la paciente depositó sus larvas desencadenando la enfermedad.
Background: onchocercosis, also known as Robles’ disease, is a chronic parasitic disease caused by a nematode worm of the genus filaria onchocerca volvulus that is transmitted by black flies of the simuliidae family and the only host of which is man. It is the second infectious cause of blindness in the world. Objective: to describe the case of a patient carrier of the disease who present a nodule in the right ascending ramus of the lower jaw. Clinical case: an African female patient who came to consultation for presenting an increase in volume of the right area of the lower jaw of some months of evolution and a tumor of six centimeters in diameter at the level of the right horizontal angle and ramus of the lower jaw. Microfilariasis was diagnosed in the cytology. Conclusions: the parasite was transmitted to the patient like it happens in all the cases, by the sting of a fly of the genus simulium that sucks the blood of the person and lays the larvae causing the disease.
ABSTRACT
Background: In Delta State, free doses of ivermectin are distributed annually to communities through the Community Directed Treatment with Ivermectin (CDTI). Despite this intervention approach, pockets of endemic foci still exits. Updated information of the epidemiology of human onchocerciasis is essential for planning effective control strategies. Thus this study aimed at investigating the current prevalence and distribution of human onchocerciasis in endemic communities of Delta State, Nigeria. Methods: A cross-sectional study was carried out in three local government areas (Aniocha North, Aniocha South and Oshimili) comprising of 41 communities in Delta State, Nigeria. A total of 1,201 consented subjects were examined by skin snips biopsy. A pre-validated well structure questionnaire was used in collecting epidemiological information. Results: The general prevalence of onchocerciasis in the studied communities was 11.5%. The prevalence did not vary among the three local government areas (P>0.05) though, the infection rate was highest in Aniocha North (12.5%), followed by Oshimili South (11.5%) and Aniocha South (10.7%). With respect to gender, the prevalence was insignificantly higher in males (12.2%) than in female (9.9%). Age-wise, the general pattern showed that the prevalence increased significantly with age. The prevalence of onchocerciasis generally differed widely among the various occupational groups sampled. The prevalence was almost two-fold among farmers (19.3%) compared to drivers and bike riders group (10.2%). Conclusion: Although the prevalence of onchocerciasis has decreased, the infection still remainsa public health concern in the area. Occupation and age were significant risk factors that affected the prevalence of onchocerciasis. Thus, there is need for control measures to be tailored towards these high risk groups. Also, intensifying community treatment with ivermectin will help eliminate onchocerciasis in the studied communities.
ABSTRACT
Background: Onchocerciasis is a chronic parasitic infection caused by the filarial nematode, Onchocerca volvulus. The objective of this study was to determine the prevalence, endemicity, and symptomatic effects of the disease in Ovia Northeast Local Government Area. Methods: The prevalence of onchocerciasis was investigated in Ovia Northeast Local Government Area of Edo State, Nigeria, between March 2008 and June 2009 using the standard skin-snip method. A total of 2020 subjects, who had visited various primary health centres located in each community, were enlisted using randomised sampling, and the data were analysed using the Chi-squared (χ2) test and logistic regression. Results: A Of the 2020 individuals examined, 1674 (83%) harboured microfilaria in their skin tissues. On the basis of the standardised scale for microfilaria prevalence—less than 10% is considered sporadic, 10%–29% is considered hypoendemic, 30%–59% is considered mesoendemic, and 60% and above is considered hyperendemic—the prevalence (83%) reported in this study led to the disease being classified as hyperendemic. Females were more frequently infected than were males, and this was statistically significant (P < 0.001). Prevalence was also found to increase with age, and this correlation was significant (P < 0.001). The prevalence of the clinical features of the disease in the local government area was 87.5% for leopard skin, 84.16% for itching, and 75.42% for nodules. Conclusion: A prevalence of 83% was observed and considered hyperendemic. Female gender and age (50 years or more) were significant risk factors that affected the prevalence of onchocerciasis. The findings demonstrated the hyperendemicity of infection and the need for urgent attention with ivermectin treatment and other control measures.
ABSTRACT
Background: Lymphatic filariasis is a mosquito-transmitted disease, while onchocerciasis is transmitted by blackflies. There is no vaccine for these infections. New drugs are required for improvement of current therapies. Objective: This article reviews recent advances in filarial parasite genomics and opportunities for new antifilarial drug research. Methods and results: Genomic approach to filarial parasites provides new prospects for target validation. Comparative genomics filters enable us to select filarial parasite-specific gene products of interest. Functional genomics filters allow the selection of gene products essential for pathogen survival. The validated targets could be prioritized and categorized by informatics methods and manual curation. Conclusion: Lymphatic filariasis and onchocerciasis can be eliminated by either sterilizing or killing adult worms. It is most advantageous to target Wolbachia species for developing new drugs. Functional genomic approaches using microarrays, proteomics, and model organisms, have significantly expanded options for researchers. The genomic-based approach is promising for anti-filarial drug discovery in the future.
ABSTRACT
Nuclear internal transcribed spacer 2 (ITS2) rDNA sequences were used for a molecular phylogenetics analysis of five Onchocerca species. The sister species of the human parasite O. volvulus was found to be the cattle parasite O. ochengi and not O. gibsoni, contrary to chromosomal evidence. The genetic differentiation of two African populations (representing the two African strains) and a Brazilian population of O. volvulus was also studied. Phylogenetic and network reconstruction did not show any clustering of ITS2 alleles on geographic or strain grounds. Furthermore, population genetics tests showed no indication of population differentiation but suggested gene flow among the three populations.
Subject(s)
Animals , Cattle , Humans , DNA, Helminth/genetics , DNA, Ribosomal Spacer/genetics , Genetic Variation , Onchocerca volvulus/genetics , Transcription, Genetic/genetics , Base Sequence , Molecular Sequence Data , PhylogenyABSTRACT
El tratamiento y control de la oncocercosis en México ha sustentado desde su inicio en la eliminación de las microfilarias con el uso de la dietilcarbamazina y la extirpación quirúrgica de los oncocercomas que arrojan los gusanos adultos. Estas medidas al parecer han disminuido la prevalencia e incidencia de la ceguera en aquellos individuos afectados por esa parasitosis. Sin embargo, no se ha logrado un impacto importante sobre la transmisión de la oncocercosis en México el control químico del vector ha tenido buenos resultados en otras regiones del mundo; en México, sin embargo no ha sido plenamente aceptado como parte integral del control de la oncocercosis por diversas causas. Más aún, pocas investigaciones se han realizado en relación a la búsqueda de nuevas alternativas para el control del vector. Recientemente, el resultado de investigaciones sobre la invermectina (agente microfilaricida) mostraron que esta droga es eficaz y segura para el tratamiento de la oncocercosis. En otros reportes se ha señalado tambien que la ivermectina tiene un efecto sobre la transmisión de esta filaria. No obstante, existen algunas interrogantes acerca de su capacidad para suspender la transmisión de la oncocercosis, discutiendo los problemas para su diagnóstico, tratamiento y control. Además se propone el empleo de parámetros para la evaluación correcta de las medidas de control, con énfasis en las determinaciones entomológicas
The treatment and control of onchocerciasis in Mexico has been supported only on the administration of diethy carbamazine and the removal of adult worms, which are in the onchocercomata. These actions seems to have diminished the prevalence and incidence of blindness in those individuals who are affected by this parasitosis. However, there has not been an important impact on onchocerciasis transmission. The objective of this paper is to critically analyze and discuss subjects related to diagnosis, treatment and control of onchocerciasis transmission in Mexico. Chemical vector control has been successfully archieved in other world regions; however, in Mexico, it has not been fully acepted as part of the integral onchocerciasis control due to several causes. Moreover, there has been few scientific research activties toward the search of new options for vector control. Recently, results of research on ivermectin (a microfilaricide agent) have indicated that this drug is effective and safe for the treatment of onchocerciasis. Additionally, it has been reported that ivermectin has an effect on the onchocerciasis transmission. However, there are several unanswered questions about the efficacy of ivermectin in toping onchocerciasis transmission. In this report, the ain efforts carried out in Mexico against onchocerciasis are analysed and problems related with diagnosis, treatment and control are also discussed Some parameters for the correct evaluation of onchocerciasis control, with entomological emphasis, are proposed.