Dispersal range of <i>Simulium neavei</i> in an onchocerciasis focus of western Uganda

Mpagi, Joseph; Katamanywa, James; Garms, R.

doi:10.1046/j.1365-2915.2000.00221.x

Cited by 18 publications

(15 citation statements)

References 5 publications

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“…But dispersal of the infective Simulium flies from onchocerciasis-endemic areas into villages where investigated persons infected with Mansonella spp. were resident is unlikely because the only vector of O. volvulus in this region is S. neavei with a greatly limited dispersal range (Mpagi et al 2000a). The findings of this study support previous reports on the specificity of Ov20 protein in filarial infections (Bradley et al 1993;Nirmalan et al 1999).…”

Section: Discussionsupporting

confidence: 86%

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Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)

Mpagi

Büttner

Tischendorf

et al. 2000

Tropical Med Int Health

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SummaryThe protein Ov20/OvS1 was used as antigen in ELISA and Western blot in order to differentiate onchocerciasis from African mansonelliasis and to characterize the hyperreactive form of Onchocerca volvulus infection (sowda). The specificity of the IgG4 Western blot was 98% for the differentiation between persons with onchocerciasis and Mansonella microfilariae (mf) carriers (125 persons with M. perstans and 92 with M. streptocerca), whereas the IgG4 ELISA showed a specificity of 81% in 137 M. perstans mf carriers and 85% in 94 M. streptocerca mf carriers. The sensitivity of Ov20/OvS1 in identifying onchocerciasis using the IgG4 ELISA was 75% for 103 O. volvulus mf carriers with the generalized and 89% for 44 patients with the sowda form of onchocerciasis. IgE antibodies against OvS1 were found in 95% of 39 patients with hyperreactive onchocerciasis but only in 15% of 47 persons with the generalized form. Thus, Ov20/-OvS1 appears a promising candidate antigen for the diagnosis of onchocerciasis and in particular for the detection of the sowda type of disease.keywords Ov20/OvS1 protein, onchocerciasis, mansonelliasis, sowda correspondence Dr N. Brattig,

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Section: Discussionsupporting

confidence: 86%

“…were resident is unlikely because the only vector of O. volvulus in this region is S . neavei with a greatly limited dispersal range (Mpagi et al . 2000a).…”

Section: Discussionmentioning

confidence: 99%

Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)

Mpagi

Büttner

Tischendorf

et al. 2000

Tropical Med Int Health

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“…9 Adult S. neavei require heavy forest canopy to survive and thrive. 10 The first studies of the Mount Elgon focus were conducted in the 1950s, when it was observed that there was a small extension of the focus into Kenya. 11 On the Uganda side of the border, vector control activities against S. neavei were carried out in 1957, largely to protect a proposed coffee research station.…”

Section: Introductionmentioning

confidence: 99%

Transmission of Onchocerca volvulus by Simulium neavei in Mount Elgon Focus of Eastern Uganda Has Been Interrupted

Katabarwa¹,

Lakwo²,

Habomugisha³

et al. 2014

The American Society of Tropical Medicine and Hygiene

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Abstract. The study determined that Simulium neavei-transmitted onchocerciasis in Mount Elgon onchocerciasis focus had been interrupted. Annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. Then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. Blood spots from 3,051 children obtained in 2009 were analyzed for Onchocerca volvulus immunoglobulin G4 antibodies. Fresh water crab host captures and blackflies collected indicated their infestation with larval stages of S. neavei and presence or absence of the vector, respectively. Mf rates dropped from 62.2% to 0.5%, and 1 (0.03%) of 3,051 children was positive for O. volvulus antibodies. Crab infestation dropped from 41.9% in 2007 to 0%, and S. neavei biting reduced to zero. Both remained zero for the next 3 years, confirming interruption of onchocerciasis transmission, and interventions were halted.

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“…However, dispersal can be wind-assisted and S. damnosum s.l. has been shown to disperse up to 500 km in west Africa when carried by seasonal monsoon winds (see Crosskey, 1990 for a review; but also see Mpagi et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Isolation by distance and a chromosomal cline in the Cayapa cytospecies of Simulium exiguum, the vector of human onchocerciasis in Ecuador

et al. 2005

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The population genetic structure of the Cayapa cytospecies of Simulium exiguum, the vector of onchocerciasis, was analysed using allozyme frequency and chromosomal inversion polymorphism data from 6 and 15 populations respectively, collected in Ecuador. Eight allozyme loci were scored. No unique allozyme markers were found enabling us to identify biting adults of the vector from the non-vector Bucay cytotype. Mannose-phosphate isomerase (Mpi) contributed largely to the significant heterogeneity in gene frequency among populations of the Cayapa cytospecies and also to the overall population structuring (F(ST) = 0.015 +/- 0.014) which fitted the isolation by distance model. However, heterozygote deficits were recorded for Mpi in four of the six populations, which could indicate that selection is acting at this locus but this hypothesis will require further convincing evidence. Furthermore the significant population structuring of allozymes was not evident when Mpi was omitted from the analysis. All inversion polymorphisms (IIS-B, IIS-F, IIL-A and IIL-B) were in Hardy-Weinberg equilibrium, showed significant heterogeneity between populations and revealed the occurrence of an altitudinal cline in inversion IIS-B frequency. The inversion polymorphisms revealed a significant degree of population structuring (F(ST) = 0.083 +/- 0.027), which can be explained by the isolation by distance model. A UPGMA cluster analysis revealed the relatively remote, high altitude Rio Mira populations to be the most genetically distinct.

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Dispersal range of Simulium neavei in an onchocerciasis focus of western Uganda

Cited by 18 publications

References 5 publications

Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)

Use of the recombinant Onchocerca volvulus protein Ov20/OvS1 for the immunodiagnostic differentiation between onchocerciasis and mansonelliasis and for the characterization of hyperreactive onchocerciasis (sowda)

Transmission of Onchocerca volvulus by Simulium neavei in Mount Elgon Focus of Eastern Uganda Has Been Interrupted

Isolation by distance and a chromosomal cline in the Cayapa cytospecies of Simulium exiguum, the vector of human onchocerciasis in Ecuador

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