ABSTRACT
On the Thai-Myanmar border, where multidrug resistance to anti-malaria medications is a major problem, a quality control program for diagnostic laboratories has been set up. This study examines the "passive" screening performed in 10 laboratories. Monthly evaluation of the quality of thick and thin smear practice, Giemsa staining and microscopy took place during the year 1994. Considering the general context and the methodology applied, the evaluation of performance and strategy of the malaria diagnostic test showed satisfactory results for all 10 laboratories. Performance of technics = 64% (62-66) to 96% (95-97); Sensitivity = 92.6 (91.5-95.5) to 96.6% (95.8-99.0); Specificity = 93.5% (91.4-95.5) to 98.3% (97.6-99.0); Predictive Positive Value = 92.0% (90.9-93.1) to 98.3% (97.6-99.0); Predictive Negative Value = 94.3% (93.0-95.6) to 98.5% (98.0-99.0). The study underlines the importance of a reliable quality control method for microscopy diagnosis of malaria in hyperendemic areas, with Plasmodium falciparum as the main species. A high level of input from the international laboratory technician, performing training, follow-up and evaluation was required. The need for adequate training of national technicians and supervisors, especially regarding long-term sustainability, is stressed. The type of program presented can be used as a model for similar projects in developing countries.
Subject(s)
Humans , Laboratories/standards , Clinical Laboratory Techniques/standards , Malaria/diagnosis , Microscopy/standards , Myanmar , Predictive Value of Tests , Quality Control , ThailandABSTRACT
Des foyers d'onchocercose a Onchocerca volvulus sont decrits pour la premiere fois au Gabon. Au cours des memes enquetes on note de fortes prevalences de porteurs de M. streptocerca et la premiere description chez l'homme de M. Rodhaini. 4922 sujets au cours de 10 enquetes portant sur l'ensemble du territoire gabonais ont subi une biopsie cutanee exsangue; un prelevement sanguin; un examen clinique. La prevalence globale des porteurs de O. volvulus est de 19;4 pour cent. Les regions les plus touchees sont : Makokou; Lebamba; Fougamou; Lastourville. Les hommes sont plus atteints que les femmes. L'infestation debute tot : 1;9 pour cent des enfants de 0-4 ans sont porteurs de microfilaires. La charge microfilarienne moyenne est de 30;7 microfilaires d'O. volvulus par biopsie. Les manifestations cliniques sont pauvres comparees a l'Afrique de l'Ouest : 36;3 pour cent des onchocerquiens sont porteurs de nodules. Les etudes des lesions oculaires n'ont porte que sur le segment anterieur de l'oeil; le pour centage de keratites ponctuees est moins important qu'en Afrique Sahelien