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Biomedical subjects

A Fenwick

Publications and source records attributed to A Fenwick.

At least 19 recordsLinked to original sources
PubMed2006

Schistosoma mansoni in infants (aged < 3 years) along the Ugandan shoreline of Lake Victoria.

In two complementary epidemiological surveys of villages on the Ugandan shoreline of Lake Victoria, the putative occurrence of intestinal schistosomiasis in the local infants (children aged < 3 years) was investigated. When, during the first survey, 136 mother-and-infant pairs from a total of 12 villages were studied, only 7% of the infants but 45% of the mothers were found to be egg-patent for Schistosoma mansoni infection. The use of dipstick tests for urine-circulating cathodic antigen indicated, however, a much higher prevalence, of approximately 40%, among the infants. In the second survey, urine samples and multiple, not single, stool samples were collected from another 19 mother-and-infant pairs in two of the 12 study villages (Bugoto and Bwondha), and a standardized questionnaire was implemented. The prevalence of egg-patent infection was then found to be markedly higher in the study infants from Bugoto (86%) than in those from Bwondha (25%). A greater level of mother-and-infant water contact, a higher abundance of (infected) Biomphalaria choanomphala, and an unusual lakeshore topology may explain why S. mansoni infection was so much more common in the Bugoto subjects than in the Bwondha. All but one of the infants studied in the second survey were found to be anaemic (with <110 g haemoglobin/litre). Taken together, these children were less likely to be found infected with hookworm (16%), Hymenolepis nana (11%) or Trichuris trichiura (5%) than with S. mansoni (47%). Infection with the parasites causing intestinal schistosomiasis can be common among the infants living in these lakeshore villages. Although the immediate and later-life clinical impacts of such infection have yet to be elucidated, such infants would probably benefit from regular de-worming. Mothers should be strongly encouraged to visit the nearest health-services clinic, with their infants, for any necessary anthelmintic treatment.

Animals↗
PubMed2005

The WHO dose pole for the administration of praziquantel is also accurate in non-African populations.

In 2001, WHO developed a pole for the administration of praziquantel without the use of weighing scales, with encouraging results in African populations. In the present study, the pole was tested on height/weight data from 9354 individuals from 11 non-African countries. In more than 98% of the individuals (95% CI 97.8-98.4) the pole estimated an acceptable dosage (30-60 mg/kg), a performance statistically similar to that observed in African populations. Reproducing the present pole in the form of a strip of paper and including it in each container of praziquantel would greatly facilitate the administration of the drug in large-scale interventions.

Adolescent↗
PubMed2005

Soil-transmitted helminthiasis in Uganda: epidemiology and cost of control.

A country-wide description of the distribution of soil-transmitted helminths in Uganda is reported, based on data for 20-185 school-children from 271 schools. The overall prevalence of Ascaris lumbricoides, Trichuris trichiura and hookworm was 6.3%, 5.0% and 43.5%, respectively. The prevalence of A. lumbricoides and T. trichiura was unevenly distributed in the country with prevalence greatest in south-western Uganda whereas hookworm was generally more homogeneously distributed. Based on preliminary cost analysis of an ongoing school-based control programme, the financial delivery cost per school-child treated with albendazole is estimated to be between US dollar 0.04 and 0.08 in different districts.

Adolescent↗
PubMed2004

Schistosoma bovis in western Uganda.

During routine parasitological surveillance and monitoring activities within a National Control Programme for control of human schistosomiasis in Uganda, it was noted that cattle grazing in a water meadow immediately adjacent to Tonya primary school, where the prevalence of intestinal schistosomiasis in children was in excess of 90%, were unusually emaciated. To test the hypothesis that there may have been an anthropozoonotic focus of Schistosoma mansoni within the local herd, a young female heifer, clearly emaciated and c. 8 months old, was slaughtered from which schistosome worms were later recovered by dissection. As female worms inspected by microscopy were not gravid, morphological identification proved inconclusive but analysis of cytochrome oxidase subunit I (COI) and small subunit (SSU) ribosomal DNA sequences from these worms identified them as Schistosoma bovis Sonsino, 1876. This is the first substantiated report of S. bovis from Lake Albert, western Uganda. Further epidemiological surveys are needed to clarify the extent of bovine schistosomiasis within this region, particularly so since this lakeside plain has been earmarked as a future game reserve.

Animals↗
PubMed2000

The epidemiology of schistosomiasis in Egypt: summary findings in nine governorates.

Health questionnaires and parasitologic examinations of urine and stool were evaluated from a stratified random sample of 89,180 individuals from 17,172 households in 251 rural communities in 9 governorates of Egypt to investigate the prevalence of, risk factors for, and changing pattern of infection with Schistosoma sp. in Egypt. A subset, every fifth household, or 18,600 subjects, had physical and ultrasound examinations to investigate the prevalence of and risk factors for morbidity. Prevalence of S. haematobium in 4 governorates in Upper Egypt in which it is endemic ranged from 4.8% to 13.7% and averaged 7.8%. The geometric mean egg count (GMEC) ranged from 7.0 to 10.0 ova/10 ml of urine and averaged 8.1. Age stratified prevalence of infection peaked at 15.7% in the 10-14-year-old age group and decreased to 3.5-5.5% in all groups more than 25 years of age. Age-stratified intensity of infection peaked at approximately 10.0 ova/10 ml of urine in the 5-14-year-old age groups and was about half that in all groups more than 25 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma mansoni was rare in Upper Egypt, being consequential in only Fayoum, which had a prevalence of 4.3% and an average intensity of infection of 44.0 ova/g of stool. Risk factors for S. haematobium infection were male gender, an age <21 years old, living in smaller communities, exposures to canal water; a history of, or treatment for, schistosomiasis, a history of burning micturition or blood in the urine, and reagent strip-detected hematuria or proteinuria. The more severe grades (II and III) of ultrasonography-detected periportal fibrosis (PPF) were rare (15 of 906) in these schistosomiasis haematobia-endemic governorates. Risk factors for morbidity (ultrasonography-detected urinary bladder wall lesions and/or obstructive uropathy) were similar to those for infection, with the exception that risk progressively increased with age. Subjects with active S. haematobium infections were 3 times as likely as those without active S. haematobium infections to have urinary tract morbidity. The prevalence of S. mansoni in 5 governorates in Lower Egypt, where it is endemic, ranged from 17.5% to 42.9% and averaged 36.4%. The GMEC ranged from 62.6 to 93.3 eggs/g of stool and averaged 81.3. Age-stratified prevalence of infection peaked at 48.3% in the 15-19-year-old age group, but averaged 35-45% in all groups more than 10 years of age. The intensity of infection was highest in the 10-14-year-old age group, and showed a range of 70-85 eggs/g of stool in those > or =5 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma haematobium was rare in these governorates; Ismailia (1.8%) had the highest infection rate. Risk factors for S. mansoni were male gender, an age >10 years old, living in smaller communities, exposures to canal water, a history of, or treatment for, schistosomiasis or blood in the stool, detection of splenomegaly by either physical examination or ultrasonography, and ultrasonography-detected PPF. The more severe grades (II and III) accounted for 463 (13.3%) of the 3,494 having ultrasonography-detected PPF. Risk factors for morbidity (ultrasonography-detected PPF) were similar to those for infection except that inhabitants of smaller communities were not at increased risk. Active S. mansoni infection increased the odds ratio (OR) of having PPF by 1.37. In comparison with others with normal-size livers, subjects having hepatic enlargement in either the midclavicular line or the midsternal line detected by physical examination or ultrasonography had a reduced risk (ORs = 0.64-0.72) of PPF. The prevalences of lesions detected by ultrasonography were 23.7% for enlargement of right lobe of the liver, 11.3% for enlargement of left hepatic lobe, 20.6% for splenomegaly, and 50.3% for PPF. Schistosoma mansoni has almost totally replaced S. haematobium in Lower E

Adolescent↗
PubMed1998

The USAID/Government of Egypt's Schistosomiasis Research Project (SRP).

Schistosomiasis is the major public health problem in rural Egypt, with almost six million Egyptians infected as at mid-1996. In 1983, the prevalence of schistosomiasis in rural Egypt was greater than 50%, but a ten-year campaign of diagnosis and treatment has reduced the prevalence and intensity of infection. Parallel to this campaign, the government of the USA has funded a research project to examine all aspects of schistosomiasis with a view to improving the control strategy. As outlined here by Taha El Khoby, Nabil Galal and Alan Fenwick, after almost ten years, the project's achievements include: assisting WHO in its attempts to develop a vaccine against schistosomiasis, developing a suspension formulation of praziquantel suitable for young children, and establishing a unit to monitor reports of resistance to praziquantel. In addition, a large epidemiological study has established the extent of the problem in Egypt. Slow-release formulation of niclosamide, health education material for use on TV, dipstick diagnostic tests, and evaluation of ultrasound as a diagnostic tool have also been achieved. As the project closes, Egypt is left with an effective strategy for the control of schistosomiasis and several back-up tools for use in the event of development of resistance to praziquantel. The Ministry of Health and Population has the basis of a Geographical Information System (GIS) unit and the country has a trained and equipped scientific community capable of biomedical research, and almost 100 scientific papers published on their work.

Journal Article↗
PubMed1988

Effect of antischistosomal chemotherapy on prevalence of Symmers' periportal fibrosis in Sudanese villages.

Almost all mortality caused by Schistosoma mansoni is secondary to Symmers' periportal fibrosis of the liver which can now be diagnosed by ultrasonography. This study assessed the usefulness of ultrasonography in measuring the effect of chemotherapy on the prevalence of Symmers' periportal fibrosis in Sudanese villagers. The prevalence of Symmers' fibrosis in 318 randomly selected patients from two villages not receiving systemic antischistosomal chemotherapy was compared with that in 168 patients from a village where antischistosomal chemotherapy had been systematically applied since 1979. The prevalence of Symmers' fibrosis was two to three times lower among treated villagers, with an eight-fold difference for villagers aged 10-20 years.

Adolescent↗
PubMed1988

Praziquantel and oltipraz: the treatment of schoolchildren infected with Schistosoma mansoni and/or Schistosoma haematobium in Gezira, Sudan.

Of 111 schoolchildren--all of whom were infected with Schistosoma mansoni and 97 of whom were also infected with S. haematobium--54 were treated with Praziquantel (2 x 20 mg kg-1) and 57 with Oltipraz (2 x 15 mg kg-1). There was no apparent difference between the efficacy of the two drugs. Follow-up studies over the following 12 months indicated that mass chemotherapy of schoolchildren can be expected to reduce the egg output of those treated by almost 100%, but that, unless there is some break in transmission, the egg output may well be as high after 12 months as it was before treatment--at least in the boys. After a round of chemotherapy, retreatment of school-aged boys in an area where transmission is heavy will be necessary six to 12 months later.

Child↗
PubMed1985

Dose-finding trial using Oltipraz to treat schoolchildren infected with Schistosoma mansoni in Gezira, Sudan.

A field trial has been carried out in Sudan to determine the optimum dosage regimen for the use of Oltipraz in the treatment of Schistosoma mansoni in schoolchildren. A total of 294 children were treated in six groups to test 15 mg/kg, 20 mg/kg, and 25 mg/kg, using a single oral dose and a divided dose taken some 6 h apart. The children were interviewed before and then 24 h after treatment to determine the prevalence of drug-induced side-effects. Most of the children having complained of abdominal pain before treatment, insisted that they suffered further abdominal pain as a result of the drug. Four children complained of fingertip pain and 17 of blurred vision. The latter side-effect had not previously been recorded in Sudan and, with the fingertip pain, is a cause for concern. There was no difference in the cumulative failure rates between the single and the divided doses, but there was a significant improvement in the efficacy from the 15 mg/kg to the higher doses. The cumulative failure rate increased with higher pretreatment egg count. However at each level the reduction in egg count among failures at the 5-week follow-up, was significant at the 95% probability level. The efficacy of the drug was satisfactory when used at 20 or 25 mg/kg, but the strange side-effects need to be explained before any further use can be recommended.

Abdomen↗
PubMed1985

Treatment with praziquantel of schoolchildren with concurrent Schistosoma mansoni and S. haematobium infections in Gezira, Sudan.

A field trial was conducted in Sudan to evaluate the acceptability and efficacy of praziquantel given to schoolchildren aged 7-11 years who were all infected with both Schistosoma mansoni and S. haematobium. Two dosage regimes were compared, a single dose of 40 mg/kg bodyweight, and a divided dose 2 X 20 mg/kg given 4-6 h apart. When interviewed 24 h after treatment, 80% of the children complained of drug-induced abdominal pain, diarrhoea, nausea or vomiting. However none of the side-effects persisted beyond the day of treatment. More children complained of side-effects from the divided dose than from the single dose. The cure rate in the divided-dose group was slightly better than in the single-dose group but the differences were not significant at any follow-up, nor when results were expressed in terms of cumulative failures. The initial cure rates were 66.3% and 61.8% at 1 month, and 73.2% and 64.7% at 3 months for the divided and single doses respectively. After 12 months there had apparently been considerable reinfection with S. mansoni and 73% of the children were passing eggs. Reinfection with S. haematobium was negligible.

Abdomen↗
PubMed1985

Field trials with Oltipraz against Schistosoma mansoni in the Gezira Irrigated Area, Sudan.

Oltipraz, a new antischistosomal drug, has been field tested in Sudan for acceptability, tolerance and efficacy against Schistosoma mansoni. One hundred and fifty-one school children aged 7 to 12 years were selected for treatment with 20 mg/kg Oltipraz, 78 with a single dose and 73 with a split dose, on the same day. The drug was well tolerated except that 20 children in one school complained of fingertip pain. Parasitological follow-up after 5 weeks, 3 and 6 months produced cure rates (i.e., 2 negative stools) of 41 to 72% with the single dose and 53 to 75% with the split dose. The overall egg output reduction was over 95% from a pretreatment geometric mean egg count of 840 eggs/g. These results indicate that a 20-mg/kg dose of Oltipraz can effectively reduce egg counts but that a larger dose will be required to produce higher cure rates.

Child↗
PubMed1985

Focality and seasonality of Schistosoma mansoni transmission in the Gezira Irrigated Area, Sudan.

In the Gezira Irrigated Area of Central Sudan, transmission of Schistosoma mansoni was shown to be geographically focal, being concentrated near villages and small settlements. In a study during 1981 and 1982 of the entire area around a typical Gezira village almost 90% of the Biomphalaria pfeifferi snails carrying schistosome infections were found in one minor canal near the village. Sites near smaller settlements some distance from the minor canals yielded few infected snails. The factors which influenced the prevalence of infection in the snails were temperature, turbidity and human contact with the snail habitat. A strategy was proposed for control of Schistosoma transmission through focal and seasonal mollusciciding, health education, chemotherapy, improved water supply and latrine distribution.

Agriculture↗
PubMed1985

Transmission of Schistosoma haematobium in North Gezira, Sudan.

During this 14-month study, 128 765 Bulinus truncatus snails were collected from canals located near four villages in the northern part of the Gezira Irrigated Area, and were examined for patent trematode infections, by exposure to light. In all, 903 shedded cercariae, of which 424 were identified as S. haematobium, and one village, Bashagra, was the source of 80% of these S. haematobium infections. The highest density of snails occurred from March to May and the peak of snail infections occurred from June through August. The residents of the four villages and any adjacent small camps were examined for infection with S. mansoni and/or S. haematobium by collecting and examining stool and urine samples. The overall prevalences were 50% for S. mansoni and 20% for S. haematobium. The age prevalence curves were very different, with the prevalence of S. haematobium falling off more sharply in the over-20 age groups than was the case with S. mansoni. Observations at the human water contact sites suggested that the transmission of S. haematobium was increased when the canals contained shallow stagnant water, when the temperature was above 26 degrees C, and when the site was frequented by small children (particularly boys aged 5-15), for swimming. Our data suggest that at any site the transmission period is short and seasonal.

Adolescent↗