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Biomedical subjects

P Jordan

Publications and source records attributed to P Jordan.

At least 127 records · Page 7Linked to original sources
PubMed1981

Reduction in transmission of Schistosoma mansoni by a four-year focal mollusciciding programme against Biomphalaria glabrata in Saint Lucia.

The effect of transmission of Schistosoma mansoni of a focal snail control programme was investigated over four years amongst approximately 1250 people living in five communities in the steep-sided Soufriere river valley, St. Lucia, West Indies. Bayer 6076 was applied from constant flow drip cans to 12 stream sections at a target dose of 8 mg/litre clonitralide every four weeks. Only proven and potential transmission sites were treated; marsh habitats, where Biomphalaria glabrata were widespread, were ignored. In the stream snail numbers were reduced by 94% in the first year and by 100% thereafter. Incidence of new S. mansoni infections amongst children fell from 18% in the last year before control to 6% and 9% after three and four years respectively. Amongst children and adults in the four years of control the conversion/reversion ratio declined leading to a lowering of the over-all prevalence from 40% to 22%. Parasitologically the results were similar to those of a previously evaluated area-wide mollusciciding programme. The mean annual cost per person protected was US $2.60. This figure is atypically high because the topography of the area severely limited the population size.

Adolescent↗
PubMed1980

Schistosoma mansoni control in Cul de Sac Valley, Saint Lucia. II. Chemotherapy as a supplement to a focal mollusciciding programme.

After an intensive area-wide mollusciciding campaign, over four and a half years, transmission of Schistosoma mansoni was reduced. A cheaper scheme suitable for the follow-up or consolidation stage of control was evaluated and two selective population chemotherapy campaigns using hycanthone (2 mg/kg b.w.) and oxamniquine (15 mg/kg b.w.) were mounted. Prevalence dropped to 6% and 3% in areas with previously high and low levels of transmission respectively. Calculations suggested that these figures were falsely low and that perhaps 20% of the population were still excreting S. mansoni ova in small numbers. The unco-operative groups in the population are probably more important in maintaining a reservoir of infection in the community than persons with light infections undetected by the sedimentation concentration stool examination technique used. The benefit of more sensitive but more costly examination techniques is not clear since the importance of very light infections in transmission is uncertain. Case detection absorbs an increasing proportion of the total cost of chemotherapy programmes with fewer cases being found amongst the same number screened. Using hycanthone (649 treated) the cost per person protected was $0.74 and using oxamniquine (264 treated) $0.94. The need to develop low cost consolidation or follow-up procedures for preventing a resurgence of transmission after successful control, when the infection is no longer of public health importance, is stressed.

Feces↗
PubMed1980

On the longevity of Schistosoma mansoni in man on St. Lucia, West Indies.

Data have been collected for at least five years in areas where transmission of Schistosoma mansoni has been controlled in the West Indian island of St. Lucia. Faecal egg output, as determined by Bell's technique, was periodically determined in 625 people and the geometric mean egg loads by year and age-group (in 1970) are presented. Assuming that egg output is linearly related to worm load, that flukes exhibit exponential survival, and survival is independent of worm load, the mean life-span of flukes within each host is calculated. It is valid to pool results for hosts ten years of age and older and a mean life-span of 3.3 years (with approximate 95% limits of 2.7 to 4.5 years) for the flukes is obtained. Results for younger hosts were heterogeneous and no pooled estimate is determined but it is suspected that the mean life-spans are greater for these hosts. The validity of some of the assumptions is discussed.

Adolescent↗
PubMed1979

A new platelet aggregation inhibitor which possesses hypolipemic and uricosuric properties, 2-[3-(2-thiazolylthio)phenyl]propionic acid (TPA).

In vitro, 2-[3-(2-thiazolylthio)phenyl]propionic acid (TPA) at plasma concentrations ranging from 0.02 to 1.0 microgram/ml prevents aggregation of human platelets induced by various aggregating agents. Oral administration of TPA to guinea pigs inhibits platelet aggregation; the estimated dose to reduce aggregation by 50% is 0.3 mg/kg. TPA protects rabbits against arachidonate-induced thromboembolic death (50% protection at 0.79 mg/kg i.p.). TPA is a potent hypotriglyceridemic agent in rats when present in the diet in concentrations as low as 0.003%. In chimpanzees, TPA is uricosuric at oral doses of 0.625 and 2.5 mg/kg. This rare combination of pharmacological properties suggests that TPA is a potentially useful antithrombotic agent.

Adenosine Diphosphate↗
PubMed1978

Blood alcohol concentrations of patients attending an accident and emergency department.

The prevalence of detectable blood alcohol in all new adult patients attending an accident and emergency department was 10.3%. The mean concentration was 20.9 mmol/1 (96 mg/dl). There were significantly more patients with detectable alcohol in the following groups: male patients; patients aged under 35 years; patients attending on Saturdays; patients attending between 21.00 and 08.59 hours; patients involved in road traffic accidents; patients presenting because of drug overdosage, and head injuries. Those with detectable blood alcohol were more likely to be admitted, probably because of their associated reason for attendance. Patients referred by their general practitioner were less likely to have detectable blood alcohol.

Accidents↗
PubMed1978

Evaluation of an experimental mollusciciding programme to control Schistosoma mansoni transmission in St Lucia.

The size and number of colonies of Biomphalaria glabrata were reduced after four years of a surveillance/treatment snail control programme using an emulsifiable concentrate of niclosamide (25% active ingredient). Surveys among the human population showed that the incidence of new Schistosoma mansoni infections in 0-10 year-old children fell from 22% to 4.3%, while in a comparison area the incidence remained at 20%. With reduced transmission over four years, the prevalence of infection in a cohort of children examined in 1971 and 1975 fell from 34% to 23%. The fall in prevalence and intensity of infection led to a reduction of 66% in the index of potential contamination, which was reflected in a reduced rate of infection among sentinel snails and representative samples of B. glabrata collected during surveillance searches.The overall annual cost of the programme was US $3.24 per capita.

Animals↗
PubMed1978

Quality control in laboratory investigations on Schistosoma mansoni in St. Lucia, West Indies. Maintenance of artificial prevalence as a laboratory aid.

A method is described of maintaining an apparent S. mansoni prevalence rate of 10% in an area estimated to have a natural rate of below 5% following two chemotherapy campaigns. To sustain interest and therefore accuracy among microscopists engaged on screening, known S. mansoni-positive stools were seeded, without their knowledge, among those collected in the field. The problems of achieving a desired level of seeding, and of a possible further dimension of the scheme are discussed.

Clinical Laboratory Techniques↗
PubMed1978

Further observations from St Lucia on control of Schistosoma mansoni transmission by provision of domestic water supplies.

Individual households in five settlements were provided with piped water in a pilot scheme to investigate the effect on transmission of S. mansoni in St Lucia. Nearby comparison settlements, in the same valley, were provided with water through a public standpipe system. The incidence of S. mansoni infection among children decreased in the experimental area, leading to lower prevalence rates and lower intensity of infection in all age groups. Over the study period, indices of infection increased in the comparison settlements, but by the end of the period development was making those settlements less suitable for comparison purposes and some reduction in transmission was occurring.The changes in human infection rates were reflected in the results of studies with sentinel snails. In the experimental area, infection rates gradually fell owing to reduced water contact and consequently less contamination of the river and its banks, and possibly to the gradual reduction in contamination potential of the community with reduced prevalence and intensity of infection. It is suggested that a piped water supply be considered as a method of schistosomiasis control, but that the cost should not be debited only to the control of this disease since a clean water supply has other medical and social benefits.

Adolescent↗
PubMed1977

Purified antigen radioimmunoassay in serological diagnosis of schistosomiasis mansoni.

A radioimmunoassay has been developed for detecting human schistosomiasis with a highly purified Schistosoma mansoni egg antigen labelled with iodine-125. The antigen, major serologic antigen 1 (M.S.A.1), has striking immunochemical and species specificity and appears to be the principal antigen responsible for the granulomatous response to S. mansoni eggs. This 125I-antigen was tested with 5 microliter of patient serum as a potential serodiagnostic test for schistosomiasis. 92 control sera from uninfected St. Vincentian patients were seronegative. In studies on 135 lightly infected St. Lucians the 5 microliter serum 125I-M.S.A.1 serodiagnostic test was more sensitive than any tests available at the Center for Disease Control, with 64% of infected children, 83% of adolescents, and 98% of adults being positive. 49 heavily infected Kenyans of all age-groups were uniformly (100%) seropositive. Finally, a semiquantitative version of the 125I-M.S.A.1 radioimmunoassay that uses 0-5 microliter of patient sera demonstrated quantitatively significant differences among age-watched and intensity-watched groups of patients with S. mansoni, S. haematobium, and S. japonicum infections.

Adolescent↗