Lymphatic filariasis in the Caribbean region: the opportunity for its elimination and certification

In order to support the case for a certification of elimination of lymphatic filariasis (LF) in some Caribbean countries, we compared the prevalence of circulating Wucheria bancrofti antigen in communities in Guyana, Suriname, and Trinidad. For the study, we assayed school children in six communities in Guyana, five communities in Suriname, and three communities in Trinidad for the prevalence of circulating W. bancrofti antigen, using a new immunochromatographic test for LF. We also assayed adults in these three countries, with a special focus on Blanchisseusse, Trinidad, where mass treatment for LF elimination had been carried out in 1981. The prevalence of W. bancrofti circulating antigen found in the school children populations ranged from 1.7 percent to 33.2 percent in Guyana and were .22 percent overall in Suriname and 0.0 percent in Trinidad. Among adults in two Guyana communities the prevalences were 16.7 percent and 32.1 percent. The results were all negative from 211 adults in communities in the north, center, and south of Trinidad, as well as from 29 adults in Suriname. The data suggest that contrary to reports of LF endemicity from the World Health Organization, LF may no longer be present in Trinidad and may be of very low prevalence in Suriname. Trinidad and Tobago and other Caribbean nations proven negative could seek to be awarded a certificate of LF elimination. In Suriname the small localized pocket of infected persons who may serve as a reservoir of LF infection could be tested and appropriately treated to achieve LF elimination. Such LF-positive countries as Guyana should access new international resources being made available for LF elimination efforts. An adequate certification program would help identify which countries should seek the new LF elimination resources (AU)

Antigenic variability in trichuris trichiura populations

The present study examines antigenic variability for the human whipworm Trichuris trichiura. Recognition by IgG of somatic antigens of individual worms collected from 3 intensely infected children from Jamaica, West Indies has been investigated by immunoblotting. When probed with 1 plasma sample, significant differences in recognition of 2 selected antigens among worm populations and between male and female worms was observed. In addition, there was evidence for antigenic variability within worm populations at the individual worm level. Such variations may have considerable implications for the development of immunity to parasitic nematodes.(AU)

Prospective evaluation of enzyme-linked immunosorbent assay and immunoblot methods for the diagnosis of endemic Strongyloides stercoralis infection

Recently described enzyme-linked immunosorbent assay (ELISA) and immunoblot methods for the detection of serum IgG against Strongyloides stercoralis larval antigens were prospectively evaluated for the diagnosis of endemic strongyloidiasis. A modification of the ELISA involved preincubation of sera with Onchocerca gutturosa phosphate-buffered saline-soluble extract to remove cross-reactivity with other helminths. The sensitivity of the ELISA increased from 80 percent and 85 percent following preincubation. Similarly, there was an increase in specifity from 94 percent to 97 percent. The IgG recognition of 41-, 31-, and 28-kD filariform larval components showed sensitivities of 100 percent, 85 percent and 65 percent, respectively. Both the ELISA following incubation of sera with O. gutturosa extract and serum IgG reactivity to a 41-kD larval component using immunoblotting are sensitive and specific techniques for diagnosing endemic strongyloidiasis.(AU)

Serum IgG reactivity with 41-, 31- and 28-kDa larval proteins of Strongyloides stercoralis in individuals with strongyloidiasis

Proteins from a deoxycholate-soluble extract of Strongyloides stercoralis infective larvae were separated by SDS-PAGE, blotting onto nitrocellulose paper, and reacted with sera from individuals with confirmed S. stercoralis infections (n = 100), suspectedS. stercoralis infections in whom no larvae could be detected (n = 27), and other nematode infections (40 with Wuchereria bancrofti, 20 with Onchocerca volvulus, 20 with Necator americanus, and 20 with mixed Ascaris lumbricoides and Trichuris trichiura infections). Immunodominant proteins of approximately 41, 31, and 28 kDa were recongnized by IgG in 91 percent, 88 percent and 90 percent respectively, of sera from those with confirmed strongyloidiasis; in 100 percent, 100 percent, and 93 percent of sera from those with suspected strongyloidiasis; and in 9 percent, 12 percent and 14 percent of sera from those infected with other nematodes. IgG reactivity to each of these proteins was a more specific means of immunodiagnosis than the currently use indirect ELISA; the methods were equally sensitive.(AU)