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Biomedical subjects

N Tafari

Publications and source records attributed to N Tafari.

At least 19 recordsLinked to original sources
PubMed1996

Evaluating new vaccines for developing countries. Efficacy or effectiveness?

Despite the profusion of promising new vaccines against illnesses prevalent in developing countries, uncertainties about the balance between costs and benefits of new vaccines have retarded their use in public health practice. Conventional prelicensure trials of vaccine protection exacerbate these uncertainties by focusing on measurement of vaccine efficacy--the performance of a vaccine under idealized conditions. Vaccine effectiveness trials provide a more pragmatic perspective by addressing the performance of a vaccine under the ordinary conditions of a public health program, by capturing direct as well as indirect effects of vaccination, and by comprehensively addressing outcomes of public health concern. The use of effectiveness trials should enable more rational triaging of new vaccines for developing countries and may accelerate the introduction of new vaccines into public health practice by resolving speculative debates about practical costs and benefits.

Case-Control Studies↗
PubMed1994

Development of a practical screening tool to identify preterm, low-birthweight neonates in Ethiopia.

Preterm, low-birthweight (LBW) newborn infants are at high risk of neonatal mortality and morbidity and need early referral for special paediatric care. In developing countries, birthweight and gestational age often cannot be measured and a practical screening tool based on surrogate neonatal body measurements to identify high-risk infants would be very useful. We studied a consecutive series of 843 singleton infants born at a referral hospital in Addis Ababa, Ethiopia. Gestational age, birthweight, and four body measurements (chest, head, and mid-arm circumferences and length) were accurately recorded. We randomly divided the series into equal-sized training and validation groups. In the training group, we used a recursive partitioning technique to develop a simple predictive algorithm--infants were classified as high risk if head circumference was 31 cm or less or if chest circumference was 30 cm or less, and were classified as low risk otherwise. When tested in the validation group, this algorithm had sensitivity, specificity, and negative predictive value for prediction of preterm and LBW births above 90%. Thus, neonatal body measurements can be combined into a pragmatic, accurate screening tool suitable for clinical use in developing countries.

Anthropometry↗
PubMed1994

Comparison of heated water-filled mattress and space-heated room with infant incubator in providing warmth to low birthweight newborns.

BACKGROUND: Prevention of excessive heat loss is fundamental to survival of low birthweight (LBW) newborns. The use of infant incubators (INC) is beyond the resources of developing countries, and the space-heated room (SHR) has been the only feasible means of providing thermal protection to LBW newborns. Recently a thermostatically controlled, heated, water-filled mattress (HWM) has been developed as a potentially simpler and affordable alternative. METHODS: In a neonatal care ward of a referral hospital in Addis Ababa, 62 < 1 week old newborns, weighing 1000-1999 g, who were well enough to breathe comfortably in room air and tolerate oral feeds, were randomly allocated to INC, HWM or SHR and followed for 3 weeks. The level of cold stress as assessed by core-to-skin temperature gradient and the rate of weight gain were the main outcome measures. RESULTS: The level of cold stress was lowest in the INC, intermediate in the HWM and highest in the SHR. Relative to the INC group, the HWM group exhibited a modest increase in the occurrence of clinically important hyperthermic or hypothermic deviations in core temperature (rate ratio (RR) = 2.3; 95% CI: 0.9, 5.6), and the SHR displayed a definite increase (RR = 4.0; 95% CI: 1.7, 9.3). During the first week, the rate of weight gain was highest in the INC group (3.6 g/kg/day), lowest in the SHR group (-2.3 g/kg/day, P < 0.05 versus INC) and intermediate in the HWM group (1.6 g/kg/day, P > 0.1 versus INC). CONCLUSION: Care in the SHR produced clinically significant thermal stresses and was associated with deficient early neonatal growth, but the use of HWM may constitute a feasible and clinically acceptable alternative in providing warmth to LBW newborns during the neonatal period.

Beds↗
PubMed1991

Intestinal bacteria of newborn Ethiopian infants in relation to antibiotic treatment and colonisation by potentially pathogenic gram-negative bacteria.

The aerobic and anaerobic intestinal microflora of 60 newborn infants in Addis Ababa was studied. As opposed to earlier published studies from Stockholm, there were no consistent changes of the microflora attributable to antibiotic treatment. The reason why antimicrobial agents caused quantitatively smaller changes of the intestinal microflora in newborn infants in Addis Ababa than in Stockholm is not known, but may be due to antimicrobial inactivation, or marked, continuous ingestion of bacteria. Colonisation by potentially pathogenic gram-negative bacteria was coupled to a low isolation rate of bifidobacterium, but not of lactobacillus. This is consistent with the hypothesis that bifidobacterium might convey some kind of resistance to colonisation by and overgrowth of gram-negative bacteria in newborn infants. Similar results have previously been obtained in Stockholm. In comparison to 45 healthy infants in Stockholm, the Ethiopian infants had more enterococcus and lactobacillus and less staphylococcus and bacteroides during the first 2 weeks of life. After that time, the only difference was more frequent colonisation by lactobacillus in Addis Ababa.

Anti-Bacterial Agents↗
PubMed1986

Congenital syphilis and perinatal mortality.

About 6% of perinatal mortality in Addis Ababa, Ethiopia, is associated with congenital syphilis. We report on 65 autopsies and the accompanying maternal examinations and interviews. Congenital syphilis was most common in unwanted pregnancies, in women with previous stillborns, in those who had multiple sexual partners, and in those who did not seek antenatal medical care. Congenital syphilis causes enlargement of liver, spleen, and placenta; premature labor; and increased perinatal mortality. It is recognizable even in severely macerated stillborns.

Female↗
PubMed1985

Biologic bases for international fetal growth curves.

A simple, inexpensive method for assessing maternal nutritional status during pregnancy was sought to control for nutrition in the development of fetal growth curves for diverse populations. Triceps skinfold thickness was measured at intervals throughout pregnancy in 60 Ethiopian women. In normally nourished pregnancies this measurement increases in the first two trimesters and decreases in the third, reflecting early pregnancy storage of fat and its release in late gestation to meet the increasing energy needs of the fetus. Ethiopian women who had skinfold thickness increases and decreases as great as those in the United Kingdom (UK) had neonates as heavy as those in the UK. This may mean that Ethiopian fetuses have the same growth potential as those in the UK and that the same growth curves can be used for the two populations. Skinfold thickness measurements may be the means by which nutrition can be controlled as a growth factor in determining the intrinsic fetal growth potentials of diverse populations.

Birth Weight↗
PubMed1980

Effects of maternal undernutrition and heavy physical work during pregnancy on birth weight.

The study attempted to determine if heavy physical labour by mothers during pregnancy affected fetal growth when such mothers had calorie intakes which were below 70 per cent of WHO/FAO recommended standards. Full term infants of such mothers had a mean birth weight of 3060 +/- 355 (SD) g compared to 3270 +/- 368 SD g for the newborn of less physically active mothers on similar low calorie diets (P less than 0.01). The mothers who engaged in heavy labour had a mean pregnancy weight gain of 3.3 +/- 2.4 (SD) kg, independent of the birth weight of their offspring, compared with 5.9 +/- 3.3 kg for the less active mothers (P less than 0.001). The mothers' weight in early pregnancy had an insignificant influence on birth weights when mothers were on low calorie intakes.

Birth Weight↗
PubMed1979

Consequences of amniotic fluid infections: early neonatal septicaemia.

This study describes the results of examination of blood cultures from infants born in a community with a high prevalence of fatal amniotic fluid infection. The incidence of first-week neonatal septicaemia was 5.5 per 1000 births. Septicaemia was detected in 38% within 12 hours and 75.6% within 72 hours of birth. The aetiological pattern of the septicaemia was similar to that of fatal amniotic fluid infections. The increase in mortality from septicaemia occurred in infants born after 34 weeks of gestation. Nearly 80% of the infections apparently occurred through intact membranes. Respiratory distress with or without radiological evidence of pneumonia was the only manifestation of septicaemia in most infants under four days of age. Low Apgar scores and multiple apnoeic episodes were more common in infants with septicaemia than in those without septicaemia. Neonatal jaundice with serum bilirubin in excess of 11 mg/dl was more common in septicaemic infants and indicated poor prognosis. Meningitis associated with septicaemia occurred in 3.8% and in all these infants the diagnosis of septicaemia was delayed beyond 72 hours. The results suggest that early recognition and treatment of antenatal bacterial infections may prevent mortality and morbidity from complications of septicaemia such as neonatal apnoea, meningitis and bilirubin encephalopathy.

Amniotic Fluid↗
PubMed1979

Perinatal death due to abruptio placentae in an African city.

Abruptio placentae was a common cause of perinatal death in Addis Ababa, Ethiopia in 1974-1975 with a frequency of 5.5/1000 births. This disorder had its peak frequency at term. No abnormalities were found in the placentas to explain the placental abruptions but there were other clues to their genesis. There was a strong association of the fatal abruptions with severe poverty in the mothers. These poor mothers were both undernourished and malnourished during pregnancy. Their fetuses and neonates who died had multiple evidences of undernutrition including a relative undergrowth of adrenals, spleens and livers and a relative acceleration of lung maturation. These findings support observations in more prosperous nations that poor nutrition of the gravida may have an important role in the genesis of abruptio placentae.

Abruptio Placentae↗
PubMed1978

Twins: causes of perinatal death in 12 United States cities and one African city.

The perinatal mortality rate in a large U. S. study was 139 per 1,000 births for twins and 33 per 1,000 for singletons. Sixteen per cent of the twin deaths were due to amniotic fluid infections, 11 per cent to premature rupture of the membranes, 8 per cent to the monovular twin transfusion syndrome, 8 per cent to large placental infarcts, 7 per cent to congenital anomalies, and the rest to over 20 other disorders. The perinatal mortality rate for monozygotic twins was 2.7 times that for dizygotic twins, mainly due to more amniotic fluid infections, congenital anomalies, and the twin transfusion syndrome in the monozygotic pairs. To study the role of poor maternal nutrition on twins, a similar study of perinatal mortality rates was undertaken in Addis Ababa, Ethiopia. Addis Ababa twins had 2.5 times the mortality rate of U. S. twins, mainly due to a higher frequency of amniotic fluid infections, abruptio placentae, cord accidents, obstructed labors, congenital syphillis, and the twin transfusion syndrome in the Ethiopians.

Abruptio Placentae↗
PubMed1978

Bacterial meningitis in childhood in an African city. Factors influencing aetiology and outcome.

In a retrospective study of 120 children aged 1 month and above with bacterial meningitis confirmed by positive CSF culture, 88.4% were found to be due to three common organisms: H. influenzae, Str. pneumoniae and N. meinigitidis. Gram-negative enteric organisms accounted for 10% of the infections. Despite intensive antibiotic and ancillary therapy, there has been no significant change in case fatality and sequelae over the past decade in this institution. The present study confirms that factors related to the organism and the host are important in determining the outcome of therapy. H. influenzae and Str. pneumoniae infections are associated with statistically significant rise in case fatality rate and neurologic sequelae at the end of therapy. The presence of neurological abnormality at the time of diagnosis significantly increases case fatality rate while delay in diagnosis appears to primarily influence the frequency of neurological sequelae. Protein-energy malnutrition increases the frequency of neurological sequelae and death from bacterial meningitis without significantly influencing the pattern of bacterial aetiology. The finding of enteric Gram-negative meningitis in association with diarrhoeal disease in the present study adds a new dimension to one of the most prevalent health problems in developing countries and needs to be confirmed.

Adolescent↗
PubMed1977

Failure of bacterial growth inhibition by amniotic fluid.

The bactericidal properties of amniotic fluid normally protect fetuses from late gestational infections by bacteria. Recently, such infections were found responsible for nearly a third of the perinatal deaths in Addis Ababa, Ethiopia. This prompted an analysis of the antimicrobial activity of amniotic fluid in patients in that city. The antimicrobial activity of fluid from 53 women, collected at term, was measured by a semiquantitative plate-count technique. Only one of the fluid samples was bactericidal, 12 were bacteriostatic, and 40 were noninhibitory to bacterial growth.

Amniotic Fluid↗
PubMed1977

Amniotic fluid infections in an African city.

Amniotic fluid infections were the most common cause of perinatal death in Addis Ababa, Ethiopia (21.8/1,000 live births). Most such infections appear to originate in the fetal membranes near the cervical os. The high rate of spread of these local infections into the amniotic fluid in Addis Ababa appears related to a lack of antimicrobial activity in amniotic fluids. Factors that adversely affected nutrition in the gravid woman, lack of prenatal medical care, and low water usage were associated with the high rate of fatal infections.

Amniotic Fluid↗
PubMed1977

Epidemiological features of perinatal death due to obstructed labour in Addis Ababa.

Obstructed labour was the second most common cause of perinatal death in Addis Ababa, Ethiopia, being responsible for 9.1 perinatal deaths/1000 births. Most obstructed labours were due to cephalopelvic disporportion. There was a ninefold increase in the perinatal death rate when the patients were anaemic but most perinatal deaths were due to delays in seeking available obstetrical care. Formal education of the patients had little influence on the death rates but the informal education that comes with prolonged urban residence had a markedly favourable effect. Use of prenatal medical services and adequate income also had a favourable influence.

Anemia↗