The diagnostic efficacy of thick blood film depends on well-trained technicians with experience in reading the slides. Parasites had already been present in the smears of peripheral blood collected on admission, but had not been noticed. Microscopy technicians frequently have difficulties in recognizing malaria etiologic agent of disease outside the endemic areas. Errors in parasitological diagnosis like false negative and positive are reported. False negative results may lead to the absence of treatment and thus to the remaining of the source of infection for the vector.
Malaria diagnosis in the case here reported was firstly made in bone marrow aspirate instead of in blood. reported patients with Plasmodium gametocytes identified in bone marrow and/or splenic aspirates of patients with visceral leishmaniasis in Sudan. This shows that skilled technicians are able to recognize malaria parasites when they are trained to. Training microscopy technicians is one of the key measures for controlling malaria. Besides professional training and competence, deficiency in microscopy skills has been admitted as a result of multiple factors, including technique in preparing the slides, conditions of the microscope and quality of laboratory supplies.
However, even with similar training and equipment, the difference in individual skills between the microscopy technicians is significant and even in developed countries technicians skilled in diagnosing malaria are scarce. The thick blood smear permits the differentiation of Plasmodium species and the identification of the developmental stage of the circulating parasite. A proficient microscopy technician should also be able to properly recognize the species of Plasmodium. The identification is critical for the therapy since treatment should be determined on the basis of the infecting Plasmodium species. Malaria is often a debilitating illness, and when caused by P. falciparum a delay in treatment may have fatal consequences, especially for in infants and young children, P.vivax malaria is worrying too, with severe cases emerging and causing an increased number and rate of hospital admissions
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