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Biomedical subjects

P Byass

Publications and source records attributed to P Byass.

At least 37 records · Page 2Linked to original sources
PubMed1996

A one-year community study of under-fives in rural Ethiopia: health and behavioural determinants of morbidity.

Based on a one-year weekly home surveillance study, morbidity patterns of 1,304 children under five years of age in a rural Ethiopian community were measured, together with nutritional and health behavioural determinants. Using Poisson regression models, the study showed that nutritional and health care factors make a significant impact on under-five morbidity. Gastroenteritis was particularly associated with child care factors, while acute respiratory infections were particularly associated with nutritional factors. Lack of immunization, low birthweight and pre-term delivery (more than one month early) were not found to have any independent effect on morbidity. Breast feeding was universal, but the introduction of supplementary foods was found to protect from excess morbidity. The study concludes by discussing possible applications of the results in intervention programmes.

Age Distribution↗
PubMed1995

A one-year community study of under-fives in rural Ethiopia: patterns of morbidity and public health risk factors.

A prospective weekly home surveillance study was undertaken to determine morbidity patterns within the Butajira Rural Health project in central Ethiopia. Overall prevalence of illness was 5.8% in 1216 person-years observed among rural Ethiopian children aged under 5 years. Acute respiratory infections (ARI) (prevalence 2.8%) and acute diarrhoea (2.4%) were the commonest conditions. Episodes of illness were distributed unequally among children, with a mean of 2.34 episodes per child. These included an average of 1.13 episodes of ARI (of which 0.16 had lower respiratory symptoms [ALRI]) and 1.17 episodes of acute diarrhoea. Sanitation factors were the principal risks for gastroenteritis, while living in rural areas predisposed children to ARI. Parental factors such as illiteracy were also linked to morbidity.

Acute Disease↗
PubMed1995

Assessment and possible control of endemic measles in urban Nigeria.

BACKGROUND: Measles remains as a serious problem of infancy and childhood in the developing world, despite the availability of a vaccine. Increasing urbanization is changing patterns of endemicity. METHODS: A survey of measles in an urban area of Nigeria, using a rapid assessment approach, was carried out to characterize measles in this community. RESULTS: An annual incidence rate of 11.8% among under-fives was found, associated with an acute case fatality rate of 3.3%. This level of endemicity was two orders of magnitude greater than that suggested by official case reports. An endemic, rather than epidemic, pattern was found over the six-month period of the study. Vaccine efficacy was estimated at 26%. Risk factor analyses showed the major risks for measles to be clinic attendance in the month preceding disease, households with more than one mother, and having under-five siblings. Measles itself was the principal risk factor for malnutrition and against survival. CONCLUSIONS: Improved understanding of measles epidemiology and risk factors are prerequisites for effective control. Possible strategies should include vertical vaccination efforts in addition to routine programmes.

Child, Preschool↗
PubMed1994

The immunogenicity and safety of Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in Gambian infants.

In developing countries, Haemophilus influenzae type b is a major cause of meningitis and pneumonia in the 1st year of life. The safety and immunogenicity of a Haemophilus influenzae type b polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) were evaluated in two studies of Gambian infants. In the first study, 131 infants were recruited and randomized into three groups to receive PRP-T at 1 and 3 months (group A), PRP-T at 2 and 4 months (group B) or no PRP-T (group C). The liquid form of PRP-T was used. The geometric mean titre (GMT) of anti-PRP antibody 1 month after the second dose was 0.26 microgram/ml in group A and 0.41 microgram/ml in group B. In the second study, 66 infants were given PRP-T in the lyophilized form at 2, 3 and 4 months of age. The GMT 1 month after the first dose was 0.09 microgram/ml, after the second 0.74 microgram/ml and after the third 2.32 micrograms/ml. After the third dose, 72% of children had antibody levels greater than 1.0 microgram/ml and 93% greater than 0.15 microgram/ml. No serious side-effects were observed and the rate of adverse reactions was consistent with the concurrent administration of diphtheria-tetanus-pertussis (DPT) vaccine.

Age Factors↗
PubMed1994

Daily morbidity records: recall and reliability.

Methodological issues concerning the collection and analysis of daily morbidity data in community studies in developing countries are discussed. The effects of recall period and inter-observer variation on symptom prevalence are considered in the context of a longitudinal study in The Gambia, in which prevalence fell by about half over 1-week's recall. In the same study, many infant-days were recorded separately on two occasions, allowing an assessment of reliability in this type of morbidity diary data. The implications of these findings both in terms of data quality and cost-effectiveness are discussed, with the conclusion that weekly interviews examining the previous week's morbidity on a day-by-day basis are operationally optimal.

Adverse Drug Reaction Reporting Systems↗
PubMed1994

Field evaluation of WHO-MDT of fixed duration at ALERT, Ethiopia: the AMFES project--I. MDT course completion, case-holding and another score for disability grading.

We report on 286 new leprosy patients (128 PB, 158 MB) enrolled in the AMFES project, a field study in which patients are monitored during WHO-MDT and during 5 years thereafter, by active surveillance. This first paper describes the purposes, organization and methods of the study, patient enrollment and preliminary results of MDT completion and case-holding. Of 128 PB patients 102 (79.7%) completed MDT and of 91 on surveillance for more than 1 year, coverage with reviews had been good or very good for 31, fair or poor for 36 and very poor or nil for 21 PB patients. Of 158 MB patients 64 had completed MDT, and 26/128 (20.3%) PB and 18/158 (11.4%) MB patients were lost to follow-up during treatment, with 76 MB patients still on treatment. At first diagnosis, 159/286 (55.6%) had nerve function impairment, with no significant differences in disability grade by gender or between PB and MB patients. The proportion of disability grade 0 amongst new cases decreased very significantly with age, from 28/41 (68.3%) for age 0-14 years to 13/57 (22.8%) for 50 years and above. In view of the limitations of patient disability grades, a score per patient of the sum of disability grades for the four extremities, named 'HF-impairment score', is shown to be more informative. Incidence of leprosy reactions and neuritis in these patients, during treatment and during surveillance, is reported upon in Part II (on pp. 320-332 of this issue).

Adolescent↗
PubMed1994

Field evaluation of WHO-MDT of fixed duration, at ALERT, Ethiopia: the AMFES project--II. Reaction and neuritis during and after MDT in PB and MB leprosy patients.

For a cohort of 286 leprosy patients the incidence rates and clinical manifestations of leprosy reactions during treatment and surveillance are described. Currently, individual patients had been observed for up to 4 years. It is intended that surveillance within this project should continue for up to 5 years after treatment. Of 128 PB patients, observed for 267 person-years (mean 2.1) 27 had 35 episodes of reaction, corresponding to an overall incidence rate of 131 events per 1000 person-years-at-risk (pyar). Of 158 MB patients observed for 402 person years (mean 2.5), 64 had 114 reactions, with an overall incidence of 284 events per 1000 pyar. For both PB and MB patients, incidence rates during treatment and post-MDT surveillance were similar. For PB patients, pre-existing physical impairment at the start of MDT was a significant risk factor for the occurrence of subsequent events, but this was not found in MB patients.

Confidence Intervals↗
PubMed1994

Field comparison of 10-g and 1-g filaments for the sensory testing of hands in Ethiopian leprosy patients.

In ALERT's leprosy control programme sensory testing of hands and feet is done with a nylon filament giving a 10-g stimulus, but doubts arose that early partial sensory loss in hands would not thus be discovered. In order to evaluate the relative performance of 1-g and 10-g filaments for sensory testing on the palms of hands, both filaments were used separately in a series of 1,021 examinations on several consecutive occasions in 159 leprosy patients and 97 nonleprosy controls. The 1-g filament was always felt on normal hands and does not lead to false positive findings of nerve dysfunction. If the 1-g filament were used routinely, almost twice as many instances of 'neuritis' would be discovered and treated, if the criterion for diagnosis and treatment of new nerve dysfunction remained as it is for nerves tested with the 10-g filament. It appears desirable to distinguish between testing for early sensory loss and for loss of protective sensation. The two tests may each need their own instrument and separate recording of the results.

Ethiopia↗
PubMed1993

Persistence of antibody at 18 months following vaccination of young Gambian infants with PRP-OMPC Haemophilus influenzae type b conjugate vaccine.

The rate of decline in anti-PRP antibody levels was measured in two groups of Gambian children who had been given PRP-OMPC at 1 and 3 months or 2 and 4 months of age. In the younger group (n = 70), the geometric mean titre fell from 1.32 micrograms/ml at 4 months to 0.44 micrograms/ml at 18 months. In the older group (n = 54), the geometric mean titre fell from 1.18 micrograms/ml at 5 months to 0.46 micrograms/ml at 18 months. The proportion of vaccinated children with antibody levels over 1.0 microgram/ml fell from 54% 1 month after the second dose of vaccine to 27% at the age of 18 months, while the proportion with levels over 0.15 micrograms/ml fell from 82% to 60%, with no significant differences observed between the vaccination groups. For those children who did not show evidence of environmental boosting, the half-life of anti-PRP antibody was about 100 days. This did not differ between the groups. These findings suggest that to provide lasting immunity PRP-OMPC should be given with a late booster dose at 12-15 months, as is the current practice in the USA. The need for a late booster dose may limit the value of this vaccine in developing countries where vaccination of children is difficult after the 1st year of life.

Antibodies, Bacterial↗
PubMed1991

A survey of the health of British missionaries.

The results of medical examinations carried out on 212 missionary personnel from one missionary society returning on leave to the UK are presented. The great majority of missionaries worked in developing countries. They served in 27 countries altogether and for a total of 488 person years. The commonest illnesses reported overseas were malaria (87.3 per 1000 person years at risk), diarrhoea (63.5), anxiety (63.5), depression (41.0) and giardiasis (38.9). More illnesses were reported from West Africa (698 per 1000 person years at risk) than from any other region. Ten people (4.7%) were repatriated for health reasons and 10 relatives also returned as a consequence. Sixty per cent of those returning did so because of psychiatric illness. The highest rates of immunization achieved were for yellow fever (100% of those travelling to affected countries), tetanus (93%), polio (85%), typhoid (71%) and tuberculosis (53%). The results of urinalysis (100% of adults), full blood counts (78% of adults) and stool tests (74% of all people) are reported. The study shows that the history and psychiatric examination are an important part of the medical examination of people returning from overseas. Physical examination and urinalysis did not contribute much information, although the full blood count and absolute eosinophil count were useful tests.

Adolescent↗
PubMed1991

Ability of Anopheles gambiae mosquitoes to transmit malaria during the dry and wet seasons in an area of irrigated rice cultivation in The Gambia.

The seasonality of malaria transmission was studied in a Gambian village situated in an area where rice was cultivated. Observations were made during two dry seasons, when pump-fed irrigation was used to grow rice, and in the intervening rainy season, when rice was cultivated using a combination of irrigated and rain-fed paddies. Clinical episodes of malaria were mainly confined to the months during and soon after the rainy season. In the wet season the prevalence of parasitaemia was higher in febrile subjects than in afebrile controls but the reverse applied during the dry seasons. However, the biting rates of Anopheles gambiae complex mosquitoes in the two dry seasons (2.5 and 0.8 bites/child/night respectively) were greater than or similar to that in the rainy season (0.6 bites/child/night). The proportion of human bloodmeals (0.53 vs 0.75) and the survival of mosquitoes (parity rates of 0.41 vs 0.58) were both lower in the dry seasons than in the rains. The low prevalence of morbidity due to malaria in the dry season and the observed fall in the sporozoite rate may therefore have been due to a reduction in the vectorial capacity of the An. gambiae population. However, reduced transmission in the dry season may also have been due to the direct effect of high temperatures on the parasite in the vector.

Age Factors↗
PubMed1991

Coincidence of malaria parasitaemia and abnormal chest X-ray findings in young Gambian children.

Weekly surveillance of Gambian children aged less than 5 years for both acute lower respiratory infections (ALRI) and clinical malaria showed a high rate of coincidence between abnormal chest X-ray findings and high levels of malaria parasitaemia. Generalized interstitial X-ray changes were particularly associated with these cases of malaria parasitaemia. It is suggested that such ALRIs in these children may be attributable to malaria.

Child, Preschool↗
PubMed1991

Evaluation of a computerized field data collection system for health surveys.

A customized field data collection system (FDCS) has been developed for a hand-held computer to collect and check questionnaire data. The data quality, preparation time, and user acceptability of the system were evaluated during a malaria morbidity survey in Bakau, the Gambia. Eight field-workers collected data with either the FDCS or on paper questionnaire forms in alternate weeks over a 6-week period. Significantly fewer item errors occurred with the FDCS, and by the end of the survey period interview times were significantly less with the FDCS than with the paper and pencil questionnaire. Advanced appropriate technology may have a useful role in providing accurate and rapid information, particularly in overcoming bottlenecks in data processing, and in obviating the need for costly expertise and equipment. In developing countries this could help to improve the quality of data on health care.

Data Collection↗
PubMed1990

Acute lower respiratory infections in Gambian children: maternal perception of illness.

A study of mothers' perceptions of childhood acute respiratory infections (ARI) was performed in a rural Gambian population. A total of 25,046 interviews were recorded over a 1-year period with mothers from three villages and four hamlets, and these were analysed together with the results of surveillance of their children for episodes of ARI. Mothers recognized acute lower respiratory infection as a severe disease and recognized fast and difficult breathing as features which discriminated it from upper respiratory infections (sensitivity 73%, specificity 73%). They sought treatment for their children on 51% of occasions when chest pain was reported and on 70% of occasions when 'open chest' was reported. We conclude that even in poorly educated populations in which traditional medical beliefs and practices are widespread, it may be possible to educate mothers to identify lower respiratory infections and to seek early treatment. Community education should play a major role in all national ARI programmes and may be a critical determinant of the success of case management strategies in preventing ARI-related mortality in children.

Acute Disease↗