ABSTRACT
Maternal height is one of the risk parameters for dystocia that is often used in antenatal clinics which are organized by health centers and dispensaries in developing countries. In this paper, the results of an analysis on the reliability of height measurements in four African countries: Benin, the Congo, Senegal and Zaire are presented. Different causes appear to reduce this reliability: attraction to round numbers, assignment of some standard size, and in one situation an overrecording (probably intentional) of an at-risk woman. Different solutions are being suggested, and the importance of assessing the quality of risk factor measurement in improving the efficacy of the risk approach strategy is stressed.
Subject(s)
Body Height , Dystocia/etiology , Africa , Anthropometry , Dystocia/epidemiology , Female , Humans , Pregnancy , Prenatal Care , Reproducibility of Results , Risk FactorsABSTRACT
This paper reports on some of the findings of a longitudinal multi-round investigation into the predictive power of early signs and symptoms of human African trypanosomiasis caused by T.b. gambiense, in the Rural Health Zone of Kasongo (Maniema, Zaire). It assesses the importance of the effect of age and a history of previously treated sleeping sickness on serological positivity as measured by the Indirect Fluorescent Antibody Test (IFAT), used as a screening test. The impact of including age and a history of previous sleeping sickness as part of the screening process is discussed in terms of sensitivity and positive predictive value. Including weak serological positivity among the screening criteria does not appear to improve the sensitivity of the IFAT test in this setting.
Subject(s)
Antibodies, Protozoan/isolation & purification , Fluorescent Antibody Technique , Trypanosoma brucei gambiense/immunology , Adolescent , Adult , Age Factors , Animals , Child , Child, Preschool , False Negative Reactions , False Positive Reactions , Humans , Infant , Longitudinal Studies , Middle Aged , Predictive Value of Tests , Prospective Studies , Sensitivity and Specificity , Seroepidemiologic Studies , Trypanosomiasis, African/drug therapy , Trypanosomiasis, African/immunologyABSTRACT
A causal model links together, in an hierarchical manner, a set of hypotheses about the causes of, and mechanisms leading to, a phenomenon under study. Initially used in nutrition studies for identifying the variables to be observed, such models have proven useful in the choice and evaluation of interventions, as well as in the selection of relevant special studies to be carried out inside a broader research programme. The authors describe a technique of model building used by nutritionists, and argue that this approach could be of benefit in the study and control of african trypanosomiasis. Their hypothesis is that although causal models do not substitute for mathematical models, the latter ones, and epidemiological models in general, would be (1) more correct logically; (2) fitting reality more closely; and (3) more useful for the analyst, the decision maker and the field worker, if they were built from an preceding causal model.
