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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Six chimpanzees (Pan troglodytes) and six mangabey monkeys (Cercocebus atys) were inoculated with Onchocerca volvulus third-stage larvae (L3) of West African origin. Two chimpanzees each received 200, 300, or 400 L3, while three mangabeys each received either 50 or 250 L3. All six chimpanzees became microfilaria positive between 11 and 25 months postinoculation (PI), while two of the six mangabeys were skin-snip positive at 24 and 37 months PI, respectively. All chimpanzees developed antibodies to two native antigens of 14 and 22 kDa and to the recombinant antigens OV16, OC3.6, and OC9.3. Marked antibody responses were observed in the mangabey monkeys, and in general, the responses were similar to those observed in the chimpanzees. However, in the mangabeys, these responses did not generally manifest themselves until later in the infection. The results of this study suggest that in chimpanzees, the smallest inoculum used, 200 L3, was sufficient to initiate consistent infections that had parasitologic and immunologic parameters equivalent to animals inoculated with larger numbers of larvae. Similarly, inoculation of mangabey monkeys with small numbers of larvae appeared to be as likely to establish infection and induce immunologic responses as did inoculation of larger numbers of larvae. Microfilaria-positive chimpanzees and mangabey monkeys were examined by three conventional imaging techniques (X ray, ultrasound, and magnetic resonance imaging (MRI)), but no adult worms or nodules could be identified in any animal.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Onchocerca volvulus: parasitologic and serologic responses in experimentally infected chimpanzees and mangabey monkeys. 772 80

Samples of human serum, skin and urine, collected in Cameroon, were used to assess the value of some newer methods for the diagnosis of onchocerciasis. Parasite DNA was detected in skin snips and urine by PCR, and parasite antigen was detected in serum and urine by immunoblotting. Serum concentrations of IgG4 antibodies reacting with recombinant Onchocerca volvulus antigens (OC3.6 and OC9.3) were also measured, using an ELISA. The PCR-based tests of skin snips and the serological tests for antigen and antibody tests showed higher sensitivities (90%-100%) than the urine PCR (14%) or the urine antigen test (68%). Although antibody detection is much easier to perform than tests based on PCR or antigen detection, the latter have an advantage in that they are only positive in people with current infections. Thus, antibody testing may be more useful for screening populations for infection or exposure to O. volvulus, whereas PCR and antigen testing are potentially more useful for diagnosis of infections in individuals and for monitoring the success of therapy.
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PMID:A comparison of newer tests for the diagnosis of onchocerciasis. 1088 70

We monitored skin microfilarial conversion and antibody (serum) conversion rates to Onchocerca volvulus recombinant antigens (OC3.6 and OC9.3) over a 2-year period, in a cohort of 208 children aged 9-11 years and living in a mesoendemic focus of savannah-type onchocerciasis in Nigeria in order to detect prepatent onchocerciasis in children. Between time point A and time point B (9 months apart) the seroconversion rate was 19.4 per cent, and between time points B and C (15 months apart), a further 31.4 per cent of seronegative children had seroconverted. However, only a third of the seroconverted children became microfilaria-positive. From the time-lag between antibody conversion and skin snip conversion, we estimated that a 9-12 month interval was required for the detection of O. volvulus microfilariae following infection with viable third stage larva (L3s). The predictive value of antibody detection as a measure of skin microfilarial conversion was >90 per cent when the optical density (OD) at 490 nm was >0.80. We therefore propose a strategy for monitoring changes in transmission of onchocerciasis following vector control or chemotherapy through an evaluation of annual antibody seroconversion rates in a standardized sentinel population of children.
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PMID:Longitudinal studies of skin microfilaria and antibody conversion rates in children living in an endemic focus of onchocerciasis in Nigeria. 1119 Nov 46