Infectivity of Simulium damnosum s.l. and therapeutic coverage of ivermectin distribution 10 years post treatment around Owena Dam, Ondo state, Nigeria

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.

Distribution and utilisation of Ivermectin [MECTIZAN]: a chemotherapeutic approach to the control of onchocer-ciasis in old Ohaozara Lga, Ebonyi State, Eastern Nigeria

Onchocerciasis [river blindness] is a devastating, debilitating Stigmatising and incapacitating parasitic disease that is endemic in tropical and sub-tropical regions of the world, including Nigeria. Mass distribution of ivermectin [Mectizan] to the endemic parts of the world was initiated by the Onchocerciasis Control Programmes [OCPs]. Absolute compliance to the regimen for up to 15 years has been reported to be effective in the control of the disease. The study was carried out in Ohaozara LGA, Onicha LGA and Ivo LGA. The three [3] LGAs made up the defunct Old Ohaozara LGA. A structured questionnaire was used to generate information on knowledge of Onchocerciasis and on the use of ivermectin by the inhabitants of the communities of the study areas. The distribution coverage of ivermectin in the study areas dating from 2010 to 2014 was ascertained with drug distribution charts obtained from Ebonyi State Health Management Board [ESHMB], Abakaliki [the point source of distribution in the state], and from the health centres in communities of old Ohaozara LGA [the service delivery points [SDPs] to inhabitants of the communities. Data was analysed using descriptive statistics. Utilization of the regimen was ascertained by determining the actual number of tablets of mectizan that was administered to the patients at the various health cenrtes [service delivery points [SDPs] in the communities. The percentage utilization of the regimen was determined by dividing the number of mectizan tablets administered to the patients at SDPs with the number of mectizan tablets supplied from state point source of distribution and multiplying by 100. A total of 347, 299 out of 1, 919135 tablets of mectizan supplied to the study areas from 2010 to 2014 were actually utilized, forming an overall percentage utilization of 18.10%. There was adequate supply but very poor utilization of the regimen. The poor utilization resulted from factors including locating of health centres very far from homes of some of the rural villagers, non-yearly compliance with regimen administration, poor health sensitization and education and lack of incentives or poor incentives to the village-based health workers [VBHWs]. Intensification of efforts to cover the lapses in the utilization of the regimen is advocated for a more effective control of the disease

Adverse reactions from community directed treatment with ivermectin (CDTI ) for onchocerciasis and loiasis in Ondo State, Nigeria

Onchocerciasis is an endemic disease in Ondo state, Nigeria. Community directed distribution of ivermectin is currently on-going in some local government areas of the state. Randomly selected persons (2 331 males and 2 469 females) were interviewed using a modified rapid assessment procedure for Loa loa (RAPLOA) to assess community directed treatment with ivermectin. The retrospective study evaluated the coverage, impacts and adverse reactions to the drug treatment. A questionnaire was administered by house-to-house visit in six local government areas, implementing community directed treatment with ivermectin (CDTI) in this bioclimatic zone. A total of 2,398 respondents were reported to have participated in the treatment. The overall ivermectin coverage of 49.96% was recorded (range 0 - 52% in different communities). Adverse reactions from ivermectin administration were experienced in 38% of individuals. Diverse adverse reactions experienced included predominantly itching (18.50%); oedema, especially of the face and the limbs (8.2%); rashes (3.4%) and body weakness (2.4%). Expulsion of intestinal worms occurred in 0.96% of the respondents. The occurrence of adverse reactions in relation to age categories was statistically significant. Neither fatal nor severe adverse reactions were reported by respondents. Significantly, despite experienced adverse reactions, continued participation, acceptability and compliance to ivermectin treatment was expressed by the various communities. This attitude is in consonance with the African Programme for Onchocerciasis Control (APOC) objectives. Rev. Biol. Trop. 56 (4): 1635-1643. Epub 2008 December 12.

La oncocercosis es endémica en el estado Ondo, Nigeria. Se seleccionaron 4 800 personas al azar para evaluar con encuesta retrospectiva la cobertura, efectos y reacciones al tratamiento farmacológico con ivermectina administrado por la misma comunidad. La cobertura global de ivermectina fue 50 % con reacciones adversas en 38 % de los individuos. Estas fueron comezón picazón (18%), edema, especialmente de la cara y las extremidades (8%), erupciones cutáneas (3%) y debilidad (2%); dependieron de la edad y no hubo reacciones más graves. La expulsión de las lombrices intestinales se produjo en 96% de los encuestados. A pesar de las reacciones adversas, hubo continuidad, aceptación y cumplimiento del tratamiento con ivermectina, en consonancia con los objetivos del Programa Africano para el Control de Oncocercosis (APOC).

Population dynamics of onchocerca volvulus microfilariae in human host after six years of drug control.

BACKGROUND & OBJECTIVES: Mass administration of ivermectin drug was carried out annually between 1995 and 2001 in three villages that were endemic for onchocerciasis in the Lower Cross River Basin, Nigeria. The aim of this study was to evaluate the population dynamics (dispersion patterns, distribution, prevalence and intensity) of Onchocerca volvulus microfilariae in their human host after six years of ivermectin treatment. METHODS: A total of 1014 subjects from three rural areas in Etung Local Government Area of Cross River State, Nigeria were screened for skin microfilariae using standard parasitological method of diagnosis. RESULTS: Ivermectin drug intervention had significantly reduced the prevalence of skin microfilariae (PMF) from 69.3% pre-control to 39.3% and community microfilarial load (CMFL) from 7.11 to 2.31 microfilariae per skin snip. Males (45%) were significantly (p <0.05) more infected than females (34%). Both microfilarial prevalence and intensity increased with age. Pearson correlation test between intensity and age was not significant (r = 0.37; p >0.05). The correlation between age-dependent parasite prevalence and mean abundance was also not significant (r = 0.42; p >0.05). The degree of dispersion as measured by variance to mean ratio (VMR), coefficient of variation (CV) and exponent 'K' of the negative binomial model of distribution showed that the parasite aggregated, clumped and overdispersed in their human host. The relative index of potential infection of each age group showed that adults between the age of 21 and 50 yr accounted for 52.7% of microfilariae positive cases. INTERPRETATION & CONCLUSION: Aggregated and overdispersion of O. volvulus observed in this study showed that active transmission could still be going on, because the tendency of the vector, Simulium damnosum ingesting more microfilariae was high due to the aggregated and overdispersed nature of the parasite with its host.

Market survey of loiasis: prevalence and adverse reactions to ivermectin using a rapid procedure for loiasis / Encuesta de mercado de loiasis: prevalencia y reacciones adversas a la ivermectina usando un procedimiento rápido para la loiasis

OBJECTIVES: 1. To assess the levels of endemicity of loiasis in a total of 30 selected villages covering an area of 5.2 sq km in Owo, Akure North, Akure South, Ondo East, Ondo West and Ifedore local governments in Ondo State, Nigeria, using Rapid Assessment for loiasis technique. 2. To obtain information on adverse reactions which occurred during previous administrations of the drug ivermectin used for the treatment of loiasis and onchocerciasis in the study area. METHODS: Consent was obtained from the chairman of each local government village head and individuals were co-opted into the study. A total of 480 individuals were interviewed, 80 from each of the six local governments, during the regular scheduled community market days. Survey for Loa loa was carried out according to specifications in "Guidelines for rapid Assessment of Loa loa (TDR, 2002). RESULTS: Among the 480 respondents, 80 (16.7%) reported having had a history of loiasis while 11 (2.3%) had recent occurrence of the disease. The local name given to the disease in all the villages studied is "aran oju". Respondents in Ondo East local government had an eyeworm history of 23 (28.8%) and occurrence of loiasis was 02 (2.5%), these were the highest figures recorded. Using the SPSS version 10 package for data analysis, demographic factors of age and gender were not significant determinants of prevalence (> 0.05). Ondo East and Ifedore local governments had significant levels of loiasis prevalence (p < 0.05). Adverse reactions from the retrospective ivermectin administration was 04 (0.83%). This was statistically insignificant (p > 0.05). CONCLUSION: Market surveys in rural communities were considered to be cost effective and rapid in the determination of prevalence of any disease. Since less than 40% of the respondents in the study area reported having had a history of eyeworm, the entire area was classified as "low risk" as regards the administration of ivermectin.

OBJETIVOS: 1. Evaluar los niveles de endemicidad de loiasis en un total de 30 poblados seleccionados, que abarcan un area de 5.2 sq km in Owo, Akure North, Akure South, Ondo East, Ondo West y los gobiernos locales de Ifedore in Ondo State, Nigeria, usando una evaluación rápida para técnica de loiasis. 2. Obtener información acerca de las reacciones adversas que ocurrieron durante las administraciones previas del medicamento invermectina usado para el tratamiento de loiasis y onchocerciasis en el área de estudio. MÉTODOS: Se obtuvo el consentimiento del presidente de cada uno de los gobiernos locales de los poblados de cabecera, así como de los individuos cooptados para la realización del estudio. Se entrevistaron un total de 480 individuos, 80 de cada uno de los seis gobiernos locales, durante los días de mercado regularmente programados para la comunidad. Se llevó a cabo una encuesta de Loa loa de acuerdo con las especificaciones de las "Guías para la evaluación rápida de Loa loa". RESULTADOS: De los 480 encuestados, 80 (16.7%) reportaron haber tenido una historia de loiasis, mientras que 11 (2.3%) tuvieron padecimientos recientes de esta enfermedad. El nombre local dado a esta enfermedad en todos los poblados estudiados es "aran oju". Los encuestados en el gobierno local de Ondo East local tenían antecedentes de gusano ocular de 23 (28.8%) y la manifestación de loiasis fue 02 (2.5%). Estas fueron las cifras más altas registradas. Usando el paquete SPSS versión 10 para el análisis de datos, se observó que los factores demográficos de edad y sexo no fueron significativamente determinantes de la prevalencia (> 0.05). Los gobiernos locales de Ondo East y de Ifedore tuvieron niveles significativos de prevalencia de loiasis (p < 0.05). Las reacciones adversas de la administración de ivermectina retrospectiva fue 04 (0.83%). Esto fue estadísticamente significativo (p > 0.05). CONCLUSIÓN: Las encuestas de mercado en las comunidades rurales fueron consideradas costo-efectivas y rápidas en la determinación de la prevalencia de cualquier enfermedad. Puesto que menos del 40% de los encuestados en el área de estudio reportaron haber tenido una historia de gusano ocular, toda el área fue clasificada como de "bajo riesgo" en relación con la administración de la invermectina.

The community-based treatment of onchocerciasis in Shao, Kwara State, Nigeria.

Community acceptance of and compliance with annual ivermectin treatment in Shao, a sub-urban community in Kwara State, Nigeria, were remarkably high. Of 890 subjects from 204 randomly selected households, 832 (93.5%) had taken ivermectin at least once during the six-year treatment period. An average community acceptance rate (ACAR) of 88.77% (range 85.4 - 91.9%) was recorded during this period; a community compliance rate (CCR) of 74.76% was recorded. Overt refusals, covert refusals and those excluded from treatment were low and insignificant (p > 0.05). The mean compliance age was 37.47 +/- 16.52 years. Of the subjects studied, 40.67% reported adverse reactions to ivermectin during the first round of treatment (Tx1); this number decreased significantly (p < 0.05) to 15.43% during the sixth round of treatment (Tx6). Though considerable adverse reactions were reported in the community, these did not seem to have negatively affected acceptance of and compliance with annual ivermectin treatment; in some cases, the adverse reactions were believed by the villagers to demonstrate the efficacy and effectiveness of the drug. The community showed great awareness of the disease, its treatment with ivermectin and the distribution of the drug. On the basis of the high acceptance and compliance rates, it was concluded that Shao will benefit greatly from the current African Program for Onchocerciasis Control Strategy: Community-Directed Treatment with Ivermectin (CDTI) using Community-Directed Distributors (CDDs).

Approche integree de la distribution de l'ivermectine pour les traitements de masse de l'onchocercose

Afin de repondre aux recommandations du Plan National de Developpement Sanitaire; le Programme National de Lutte contre l'Onchocercose du Congo propose une distribution de masse de l'ivermectine integree aux soins de sante primaires. Les differentes etapes necessaires a cette integration sont decrites ici

Le traitement de l'onchocercose par ivermectine en distribution de masse : etude cout-efficacite

Deux strategies de distribution de masse de l'ivermectine ont ete successivement testees dans un district du Congo: equipe mobile puis postes fixes a une periode donnee. La population qui a pu etre traitee a ete la meme dans les deux cas mais une reduction de 49 pour cent des couts a pu etre obtenue avec la seconde strategie

Anti-nematode activity of sixteen compounds against Trichinella spiralis in mice--a possible new screen for macrofilaricides.

There are few small animals models for filariasis, even more so for onchocerciasis. Therefore it is difficult to test under drug screening conditions large numbers of potentially macrofilaricidal compounds. One way around this difficulty is to use mice infected with Trichinella spiralis which by reason of anatomical location in the host would show some correlation in antinematode activity between the test and target organisms. This study investigated the activity of 16 compounds against the immature larval stage of T. spiralis. All the nine benzimidazole compounds (albendazole, flubendazole, mebendazole, oxfendazole, oxibendazole 780118, 780120, 790163, and 790392) were active, the most potent being oxfendazole. The benzothiazoles (CGP21306, CGP20376, CGP21833 and CGP24588A) also indicated some anti-nematode activity together with 35vr, an imidazopyridine, but not as marked as the benzimidazole group. However, the organic arsenical compounds (Mel Ga and Mel Ni) showed little activity and this was at a rather highly toxic level. The prospects of using the Trichinella-mouse model as a primary screen to test for potential macrofilaricides are discussed.

La oncocercosis y su relación con el aparato urinario / Onchocercosis and its relationship with urinary tract

La oncocercosis es una enfermedad parasitaria que tradicionalmente se ha considerado como un padecimiento que afecta exclusivamente a los tejifos oculares y cutáneos. Sin embargo, ya se ha demostrado que existen también otras alteraciones sistématicas, renales y neurológicas especialmente inducidas durante el tratamiento con microfilaricidas. En este artículo se hace una revisión de los aspectos renales de la oncocercosis que incluyen la presencia de microfilarias de onchocerca volvulus en orina (microfilaruria), así como de hematuria y proteinuria en pacientes infectados con esta filaria. Estas manifestaciones renales pueden observarse en oncocercosos que no se encuentran bajo tratamiento, pero su aparición es especialmente notable durante la quimioterapia tanto con microfilaricidas como con macrofilaricidas. No obstante que estas alteraciones pueden desaparecer o no después de finalizado el tratamiento, aparentemente tienen muy poca influencia en el cuadro clínico general de la oncocercosis. Se hace hincapié en los posibles mecanismos por los cuales las microfilarias de 0. volvulus pasan de los tejidos cutáneos hacia el torrente sanguíneo y, desde allí, hacia la orina. Asimismo, se comentan los mecanismos propuestos para explicar el lesión renal, mecanismos que al parecer tienen un origen inmunológico basado en el depósito de complejos inmunitarios en la membrana basal de glomérulo.

Etude clinique et parasitologique de l'onchocercose dans huit villages de la vallee du Mbam (Province du Centre; Cameroun)

Une etude a ete entreprise dans la Vallee du Mbam afin de mieux repartir l'onchocercose dans cette region. Dans chacun de ces villages; environ 150 sujets ages de cinq ans et plus ont ete examines du point de vue clinique et parasitologique. Il ressort de cette etude que tous ces villages etudies sont hyperendemiques. Cependant; les charges microfilariennes moyennes varient largement. Ainsi; cette enquete confirme qu'au Cameroun; en zone de transition savane-foret; l'onchocercose a des repercussions oculaires graves. Un traitement de masse par ivermectine serait certainement souhaitable dans la region de Bafia

Controlling river blindness with ivermectin

This paper deals with onchocerciasis which is in large areas of Africa. And the number of people at risk of contracting river blindness in endemic areas rises to 78 million in Africa. Therefore the dicovery of ivermectim is a new weapon in the war against river blindness

Quimioterapia de la oncocercosis: evaluación del mebendazol solo y asociado con dietilcarbamazina / Drug therapy of onchocercosis: evaluation of mebenzole alone and in combination with diethylcarbamazine

El objetivo de este trabajo fue evaluar la eficacia del mebendazol(MEB) solo, o en combinación con dietilcarbamazina(DEC), en un estudio abierto, controlado, en pacientes infectados con Onchocerca volvulus. Se administró MEB a dosis de 50 mg/kg/día, durante 14 días a 7 pacientes con altas cuentas de microfilarias en piel. Otros 7 pacientes recebieron 2 g de MEB diarios por 14 días (promedio 44 mg/kg/día). Adicionalmente, a estos últimos pacientes, se les agregaron 3 mg/kg/día de DEC durante los últimos cuatro días de tratamiento. Los criterios para la selección de pacientes fueron: a) cuentas de microfilarias entre 15 y 100 por biopsia de piel; b) presencia de nódulos subcutáneos y c) ausencia de severo daño ocular y enfermedades sistémicas. Los resultados mostraron que la combinación de MEB más DEC fue ineficaz para prevenir las reacciones adversas causadas por la administraçäo de DEC. Esto fue debido a la ineficacia del MEB para disminuir la carga original de microfilarias en piel antes de la administración de DEC. El MEB, administrado a 50 mg/kg/día, durante 14 días, fue incapaz de inducir un descenso significativo y substancial de las cuentas de microfilarias en piel. Sin embargo, se observó una leve reducción en las cuentas de microfilarias en piel 15 días después de iniciada la administración de la droga. Los cambios más importantes a nivel ocular fueron detectados en el grupo de pacientes que recibieron MEB. Extradiordinariamente importante, fue la movilización de microfilarias observada en la cámara anterior de los ojos de los individuos que recibieron MEB sólo. Las reacciones sistémicas adversas fueron más aparentes tanto en frecuencia como en intensidad en los pacientes que recibieron MEB más DEC, que en los pacientes que recibieron MEB solo. En conclusión, MEB dado a la dosis de 50 mg/kg/día durante 14 días, fue ineficaz para disminuir las cuentas de microfilarias en pacientes infectados con Onchocerca volvulus