Experimental and natural infection of Simulium sanchezi by Mansonella ozzardi in the Middle Orinoco region of Venezuela

Abstract

Experimental and natural infections of Simulium sanchezi by Mansonella ozzardi were studied in the area of Síquita, Territorio Federal Amazonas, Venezuela. The microfilariae developed synchronously in the blackflies, reaching stage L3 in seven to eight days at temperatures between 23 degrees and 27 degrees C. Larvae in different stages of development, including infective forms, were found in 0.6% of 662 unfed wild-caught females. These results confirm that simuliids are the main vectors of M. ozzardi in the American continent.

Simuliid blackflies (Diptera: Simuliidae) and ceratopogonid midges (Diptera: Ceratopogonidae) as vectors of Mansonella ozzardi (Nematoda: Onchocercidae) in northern Argentina

“…However, not all Culicoides species are efficient hosts to M. ozzardi. C. insinuatus was a less efficient host to this filaria in Colombia (Tidwell & Tidwell 1982), while Lowrie and Raccurt (1981) and Raccurt and Lowrie (1981) Yarzábal et al (1985), which were all more effective hosts in terms of these parameters. It has been shown by Shelley et al (1987) that S. oyapockense s.l.…”

“…Generally, species with unarmed cibaria are more effective hosts to O. volvulus than those with armed cibaria and the same must be true for M. ozzardi. All the species cited in Yarzábal et al (1985) possess cibarial teeth, whereas S. exiguum at Finca Normenta does not. This would therefore suggest that this simuliid population is a poor host to M. ozzardi because of rapid formation of the peritrophic membrane or because of an inhibitor in the thoracic musculature as is seen in some simuliid species that transmit O. volvulus in Africa and Latin America (Shelley 1988(Shelley , 1994.…”

“…In November 1995 a survey was made in the same area by staff from the hospital at Fraile Pintado to register the names of individuals infected with M. ozzardi, followed in December 1995 by a single treatment of infected Yarzábal et al 1985 individuals using ivermectin (pers. comm.…”

Ocorrência da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades ribeirinhas do rio Purus, Município de Boca do Acre, Amazonas, Brasil

“…Os simulídeos foram coletados com capturadores de sucção, fixados em álcool 70%, identificados, corados com hematoxilina e dissecados 5 . Posteriormente foram examinados em microscó-pio óptico para identificação dos estágios larvais (L1, L2 e/ou L3) 12 de M. ozzardi e estimativa da taxa de infecção parasitária (TIP) 10 .…”

Prevalence of Mansonella ozzardi among riverine communities in the municipality of Lábrea, State of Amazonas, Brazil

“…The simuliidae collected were dissected into three parts (head, thorax, and abdomen) using a stylet, under a stereoscopic microscope 13 . When filarial worms were detected, they were identified and quantified regarding developmental stage (L 1 , L 2 , or L 3 ) 14 . The parasitic infection rate (PIR) was calculated by the number of females infected with stage L 1 , L 2 and/or L 3 M. ozzardi divided by the number of females dissected, multiplied by 100. ex: examined, pos: positive, prev (%): prevalence (%), *correspond to statistical significant difference (p < 0.001) between males and females in different age groups, using G-test.…”