Sensitive and specific serodiagnosis of onchocerciasis with recombinant hybrid proteins.

Abstract

Abstract. Onchocerciasis remains a major health hazard in many tropical countries. However, the existing tools for diagnosis of the disease have limitations, particularly regarding the detection of low level or early infections. To design an optimized reagent, we exploited the high antibody reactivity of patient sera against the Onchocerca volvulus proteins Ov20 and Ov33, which have been described as highly sensitive and specific immunodiagnostic reagents for producing hybrid proteins. The construct OvH2 was composed of Ov20 fused to Ov33, while OvH3 consisted of the C-terminus of Ov20 linked to Ov33. When these constructs were tested with sera from patients with onchocerciasis and control sera, OvH2 showed a sensitivity of 98.5% and a specificity of 97.7% and OvH3 showed a sensitivity of 98.5% and a specificity of 95.35%. All non-responders were from Ecuador. These results surpass those of existing single recombinant antigens, suggesting that our hybrid proteins combined the sensitivity of the two parent proteins. Tests based on OvH2 should prove suitable for monitoring onchocerciasis control programs and individual diagnosis.

Evidence for the exacerbation of lymphedema of geochemical origin, podoconiosis, by onchocerciasis

“…Normal African Sera for determination of background reactivity in ELISA were prepared similarly from the blood of 14 subjects from Molyko-Buea, Cameroon, a non-transmission urban area. These controls were negative for onchocerciasis by the skin snip test, and had previously been shown to be serologically negative by the OvH2-based test of Nde et al [12]. …”

Preparation and Characterization of Specific Monoclonal Antibodies for the Detection of Adult Worm Infections in Onchocerciasis

“…The samples were collected at the abattoir. Control adult bovine sera were also confirmed to be negative by the serological tests (8,9) in which bovine IgG were detected. This was necessary due to the widespread distribution of bovine onchocerciasis in Cameroon, as well as the rest of the world.…”

“…The sera were confirmed to be negative using serological tests. (8,9) Cattle and cattle sera Cattle grazed in the Vina Basin (Cameroon) where bovine onchocerciasis is endemic were diagnosed for onchocerciasis, and sera (n ϭ 56) were obtained from them as described in the last section. Control bovine sera (n ϭ 17) were either newborn calf sera (NBCS; n ϭ 5) from National Veterinary Institute (SVA), Håtunaholm, Sweden, or adult bovine sera (n ϭ 12) from Bamenda, Cameroon.…”

Recent Updates on Onchocerciasis: Diagnosis and Treatment

“…Weil et al [45] presented data on a serum antibody test card that uses recombinant antigen from finger-prick whole-blood specimens to detect O. volvulus-specific IgG4. Initial results of a trial of a triple-antigen, indirect, ELISA rapidformat card test also appear to be promising [46], as do trials of a hybrid of 2 well-established sensitive and specific diagnostic antigens to produce a highly sensitive and specific antibody test [47].…”