Postmortem Brain Smear Assessment of Fatal Malaria

    Wellcome TrustMahidol UniversityOxford Tropical Medicine Research Programme, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand

    The advantages of brain smears over standard histological sections in preserving long sections of capillaries and venules and, thus, allowing quantitative assessment of parasite sequestration in fatal falciparum malaria were first reported by Raja in 1922 [1]. For the past 24 years, we have used a combination of light microscopy, immunofluorescence microscopy, and electron microscopy on postmortem perorbital brain samples and have reported results from >50 fatal cases of malaria [24]. We concur with Milner et al. [5] that the procedure is useful but disagree on the subject of quantitation. When light microscopy is used, the brain smear preparation allows a better assessment of the intensity, stage distribution, and intervessel variance of sequestration than do conventional histological sections, which are at a random plane compared with the axis of the vessel being assessed.

    References

    1.  Raja RN. Post-mortem examination in cerebral malaria: a new simple method of demonstrating parasites in the capillaries of the brain. Ind Med Gaz 1922; 57:29899. First citation in article

    2.  MacPherson GG, Warrell MJ, White NJ, Looareesuwan S, Warrell DA. Human cerebral malaria: a quantitative ultrastructural analysis of parasitized erythrocyte sequestration. Am J Pathol 1985; 119:385401. First citation in article

    3.  Silamut K, Phu NH, Whitty C, et al. A quantitative analysis of the microvascular sequestration of malaria parasites in the human brain. Am J Path 1999; 155:395410. First citation in article

    4.  Pongponratn E, Turner GDH, Day NPJ, et al. An ultrastructural study of the brain in fatal falciparum malaria. Am J Trop Med Hyg 2003; 69:34559. First citation in article

    5.  Milner DA Jr, Dzamalala CP, Liomba NG, Molyneux ME, Taylor TE. Sampling of supraorbital brain tissue after death: improving on the clinical diagnosis of cerebral malaria. J Infect Dis 2005; 191:8058. First citation in article