A controlled trial of hycanthone and placebo in schistosomiasis mansoni in St. Lucia

In a blind trial, 32 schistosomiasis mansoni patients (mean age, 12.03 years) in St. Lucia were given a single intramuscular dose (2.5 mg/kg of body weight) of either hycanthone or a vitamin placebo. The principal side effect, vomiting, was limited to four of the 16 patients given hycanthone; three patients in the hycanthone group and two of the 16 given placebo complained of abdominal pain. Daily enzyme determinations suggest that the mild elevations of serum glutamic oxaloacetic transaminase, lactic dehydrogenase and creatine phosphokinase observed in both groups were due to muscle injury at the injection site. Six months after treatment, only the hycanthone group had a marked reduction in egg excretion (99 percent), with 7/16 then excreting no eggs. The hycanthone group had a greater but statistically insignificant decrease in symptoms at six months. Of 30 patients with hepatomegaly, only the 16 in the hycanthone group showed a statistically significant decrease in liver size at six months; of seven patients with splenomegaly, the two in the hycanthone group and 1/5 in the placebo group showed a decrease in spleen size. All patients gained in weight during the study, with the mean increase for the hycanthone group being greater by 1.2 kg. At the conclusion of the study, the placebo group patients were treated with hycanthone (AU)

Preliminary parasitological results of a pilot mollusciciding campaign to control transmission of Schistosoma mansoni in St. Lucia

A mollusciciding campaign was begun in Cul-de-Sac Valley, St. Lucia, at the end of 1970, following several years of epidemiological studies in which transmission of Schistosoma mansoni was found to be high in settlements on the valley floor but low in hillside settlements. Postcontrol (1971-73) findings in children, when compared with precontrol data and with data from an adjacent valley having a similar transmission pattern, show significant reductions in prevalence, incidence, and intensity of infection.(AU)

Control of Schistosoma mansoni transmission by provision of domestic water supplies

As an experimental control measure to reduce the transmission of S. mansoni, an individual household water supply was provided in 400 houses in 5 rural settlements of the Riche Fond Valley, St. Lucia. This population of about 2000 had previously been dependent for water on infective streams and rivers. Six other settlements in the valley, all provided with limited piped water from public standpipes, served as the comparison area. After 2 years the incidence, prevalence, and intensity of infection with S. mansoni were significantly lower in the household water supply area, whereas all these indices of infection had increased in the comparision area. An aqueduct, reliable, and convenient supply of water can reduce the transmission of S. mansoni and should be considered as a control measure in other endemic areas. (AU)

Two-year follow-up of hycanthone-treated schistosomiasis mansoni patients in St. Lucia

Of 433 schistosomiasis mansoni patients in St. Lucia who were treated with hycanthone ( 3mg/kg of body weight), 190 were seen 2 years after treatment and 143 of these had attended all follow-up examinations at 6 weeks, 6 months, 1 year, and 2 years. Viable eggs were not detected in 86 percent at 1 year nor in 76 percent at 2 years. The reinfection rate, as judged by a significant increase in egg excretion, was 15 percent and was related to the geographic area to which the patient returned. Extremely high total reduction in egg excreation (98 percent) was achieved through 1 year, and even with reinfections this fell only to 87 percent at 2 years. Liver and spleen enlargement was related to intensity of infection and responded to treatment in 92 percent and 83 percent of instances, respectively. Among patients with hepatosplenomegaly, those 15 years or older showed less clinical response than younger patients but were too few for statistical comparison. (AU)

Immunological studies in Schistosoma mansoni infection in St. Lucia

An investigation was made of the immunological status of matched groups of patients with Schictosoma mansoni infection in St. Lucia, one group with hepatosplenic disease and the other with only intestinal disease. No impairment of humoral or cellular immunity was detected in either group. IgG and IgM levels were above normal range and were higher in the patients with intestinal disease, but only the difference between groups in IgG level was statistically significant. In their reaction to specific schistisome antigens and ability to develop delayed hypersensitivity, the groups were about equal. (AU)