Environmental factors and the distribution of mansonelliases in Southern Venezuela

Abstract

Summary:The distribution of mansonelliases and their relation to various quantitative criteria were determined through the study of 1,057 subjects in 17 localities in ten regions of Amazonas State and Bolivar State. The total prevalence among the blood samples, determined through the Knott technique, was 1 8.54 %. 1 1.26 % were parasited by Mansonella perstans, 9.93 % by Mansonella ozzardi, and 2.63 % by both species. The average of microfilaremia was 48.19 mf/mL of blood in /VI. perstans and 13.79 mf/mL in M. ozzardi. In the regions studied, A/I. ozzardi has a wider area of distribution than M. perstans. Prevalence, average number of parasites per host, and the infection index have a positive and statistically significant correlation with the total annual precipitation mean for each region for M. perstans; in the case of M. ozzardi the quantitative parameters are positively correlated with the altitude of each region, this correlation being statistically significant. With respect to type of vegetation, M. perstans had a higher infection index in Amazonian caatinga transition in pluvial lowland forest, and M. ozzardi in semideciduous forest of the alisio type. Therefore two types of transmission, M. ozzardi-Simulium and M. perstans-Culicoides are suggested.KEY WORDS : mansonelliasis, Venezuela, distribution, vegetation types. Résumé : FACTEURS ENVIRONNEMENTAUX ET DISTRIBUTION DES MANSONELLOSES DANS LE SUD DU VENEZUELA La distribution des mansonelloses et leurs relations à divers critères quantitatifs ont été déterminés à partir de l'étude de I 057 sujets dans 17 localités de dix régions des États d'Amazonas et de

A systematic review of the epidemiology of mansonelliasis

“…Prevalence rates from other studies in West and Central Africa demonstrate a similarly wide infection rate, ranging from 3.2% to 47% in Nigeria (Agbolade and Akinboye, 2001; Akogun, 1992; Anosike et al, 1992, 2005b; Arene and Atu, 1986; Udonsi, 1986, 1988; Ufomadu et al, 1991; Useh and Ejezie, 1995) and 6.0% in Sierra Leone (Gbakima and Sahr, 1996) to 49.1% in Gabon (Van Hoegaerden et al, 1987), 66.3% in Guinea (Vila Montlleo, 1990), and 75% in Mali (Keiser et al, 2003). The only recent study from Latin America was conducted among an indigenous population in Venezuela and found a prevalence of 11.3% (Gómez and Guerrero, 2000). A study from Colombia found a prevalence of 6% in affected communities in the 1980s (Kozek et al, 1983).…”

“…In the past ten years, the results of cross-sectional studies from Brazil (Cohen et al, 2008; Garrido and Campos, 2000; Medeiros et al, 2008), Bolivia (Bartoloni et al, 1999), and Venezuela (Gómez and Guerrero, 2000) have been published. Most of the studies in Brazil and Venezuela were conducted in communities located along rivers in the Amazon basin and focused on indigenous groups.…”

“…Most of the studies in Brazil and Venezuela were conducted in communities located along rivers in the Amazon basin and focused on indigenous groups. The prevalence rates ranged from 9.9% (Gómez and Guerrero, 2000) to 18.9% (Cohen et al, 2008) to 28.2 % (Garrido and Campos, 2000) to 30.2% (Medeiros et al, 2008). Older studies from Brazil found prevalence rates ranging from 4% (Shelley, 1975) to 27% (Lage, 1964).…”

Prevalencia y factores asociados con la filariosis por Mansonella ozzardi en 2 comunidades periurbanas de Iquitos, 2009

“…Evidenciamos la presencia de mosquitos Culicoides sp., los cuales están relacionados con la transmisión de la mansonelosis, en particular, como lo demuestra un estudio en el norte de Argentina en el que se compara el grado de infectividad de los diversos vectores a M. ozzardi; también 6 , en una región del estado de Bolívar (Venezuela), encontraron una prevalencia de filariosis de 18,5%, donde evidenciaron que la transmisión en la zona fue de M. ozzardi por el vector Simulium y del vector Culicoides para la transmisión de M. perstans. Fernandez et al 17 , entre el 2004 y 2006 en el municipio de Paunini, del estado de Amazonas (Brasil), encontraron filariosis en el 24,9%, donde evidenciaron la presencia de simúlidos en diferentes comunidades del estudio.…”

Review of Mansonella ozzardi and its Vectors in the Neotropical Region with Emphasis on the Current Situation in Haiti

“…ozzardi is located in the forest areas of the Amazon Basin [14] and the Orinoco Basin [15] where there are small foci scattered along the banks of the rivers. The countries concerned are Northern Brazil [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], the three Guianas : French Guiana [34], Surinam [35] and Guyana [36,37], Venezuela [15,[38][39][40][41], Eastern Colombia [42][43][44][45], and Northeastern Peru [46,48].…”