Anopheles freeborni Courtesy
Plasmodia seen with the microscope M. Lontie, MCH, Leuven, 2012
Diagnosis of malaria Thin film (better for species identification). Thick film (more sensitive). QBC (quantitative buffy coat, BD). Antigen-detection. Molecular methods (New Microbiol. 2001. 24:69.). Serology. (Platelet count: low in case of severe P. falciparum infection).
Thick film Blood (finger, tube), no anticoagulants. Immediately after sampling. Defibrination (at least during one minute). Not too thick. Allow drying. Quality of the water (ph). Also for Babesia, Borrelia, Trypanosoma, filaria (last pictures). U.S. Department of Health, Education, and Welfare.
Courtesy Peters W. & Gilles H.M.
Thick film Only with disposable fingerstick devices (Acta Clinica Belgica. 2005. 60:63-69.). Can also be made with blood with anticoagulants (EDTA). Allow then much longer drying.
Thick film made with EDTA blood
Diagnosis of malaria 1 parasite / 100 000 rbc = fever (nonimmune person). 100 000 rbc in a thin film = 30 min. Thick film = concentration technique. Thick film = 10 to 30 times more sensitive than thin film. Thick film = 3 to 5 (10) min. U.S. Department of Health, Education, and Welfare.
Diagnosis of malaria 1 parasite / 100 000 rbc = fever (non-immune person) = 25-50 parasites / μl. Tolerance in immune persons = 5 000-10 000 (100 000) parasites / μl. Cerebral malaria in children (P. falciparum): 1 000 000 parasites / μl associated with fatal issue. (Wéry, 1995).
Thick - thin film, objective 100 x 10 000 wbc, 5 000 000 rbc Giemsa 100 fields 0.25 μl / 10 min 2500 wbc 1 250 000 rbc one = 4 parasites / μl 50 / μl = fever in nonimmune = 12.5 / film May-Grünwald-Giemsa 100 fields 0.01 μl / 10 min 100 wbc 50 000 rbc one = 100 parasites / μl 50 / μl = fever in nonimmune = 0.5 / film Wéry M. 1995. Protozoologie Médicale.
Diagnosis of malaria Geographical distribution of different species should be taken into account. Plasmodium falciparum limited to (sub-) tropical areas (summer isotherm of 20 C, altitude < 2000 m). Mixed infections are not uncommon (eg P. falciparum + P. ovale in West Africa).
Duffy blood group system = receptor P. vivax West & Central Africa Duffy bg: absent Plasmodium ovale East Africa Duffy bg: present Plasmodium vivax Wéry M. 1995. Protozoologie Médicale.
MALARIA (falciparum) (vivax) falciparum vivax malariae (vivax) (malariae) vivax falciparum malariae vivax ovale falciparum malariae ovale According to M. Wéry, 1995
Malaria: antigens HRP-2: watersoluble histidine-rich protein from axesual stages and young gametocytes of P. falciparum (related to knob-associated HRP-1 and HRP-3). Pan-malarial antigen: pldh or aldolase, present in all four Plasmodium spp. A. Moody. 2002. CMR, 15:66-78.
Malaria antigen (HRP2) detection Sensitivity: 50-100 (and less) parasites / µl. False negatives due to very high parasitemias.
Diagnosis of malaria antigendetection Persistent positivity with gametocytes (JCM, 2001, 1025). PMA is expressed by P. malariae (JCM, 2001, 2035). Moody A. 2002. CMR, 15:66-78. Rapid diagnostic tests for malaria parasites (review).
Lee N. et al. 2006. JCM., 44:2773-2778. Effect of sequence variation in Plasmodium falciparum histidine-rich protein 2 on binding of specific monoclonal antibodies: implications for rapid diagnostic tests for malaria. Sequence variation can help to explain the variations in the performance of HRP-based RDTs and point toward possible solutions.
Prozone in 16 of 17 HRP-2 based RDTs P. Gillet. 2011. Dissertation at the Maastricht University.
Malaria antigen detection Prozone: how to avoid? Always have a look at the thick film Perform always HRP2 & LDH or aldolase If low platelets look a second time at the thick film
Species-specific PCR diagnosis of malaria (CDC) 1. P. vivax 2. P. malariae 3. P. falciparum 4. P. ovale Two step nested PCR using the primers of Snounou et al. CDC, 2001.
Detection of four Plasmodium species in blood from humans by 18S rrna gene subunit-based and species-specific real time PCR assays Rougemont M. et al. 2004. JCM, 42:5636-5643.
Malaria serology Only P. falciparum cultivated in vitro. To exclude malaria e.g. among travellers. Blood donation from travellers. For epidemiological reasons. Wéry M., 1995.
Malaria: staining procedures used Thick film: Giemsa staining. Thin film: May-Grünwald staining.
Inexpensive method of diluting Giemsa stain Petithory J.C. et al. 2005. JCM, 43:528. 29 bottles of Evian water. ph: 7.36 Ready to use and stable for weeks.
ph 7.2 = optimal ph 6.4 6.8: less coloured parasites and stippling ph 7.6: stronger coloured parasites and stippling
UK NEQAS Parasitology on the web Why is malariology so difficult? I firmly believe that knowledge and experience arises from constant practice and exposure to a wide variety of different forms of the parasites. The other problem is that no two strains of the same parasite are identical; intra-species variation is a characteristic of the malarial parasite.
Diagnosis of malaria Percentage of infected red blood cells. Ring stage. Trophozoite (growing ring stage). Schizont: number of merozoites: 2 (young) -24. Gametocytes: shape (crescentic ot rounded). Dots: James, Schüffner, Maurer. Pigment: P. malariae, P. ovale... Atypical elements. U.S. Department of Health, Education, and Welfare.
Parasitized RBC All: Plasmodium falciparum. Young (reticulocytes, larger rbc): Plasmodium ovale and Plasmodium vivax. Old (smaller rbc): Plasmodium malariae. Gentilini & Duflo. 1986.
Plasmodium falciparum vivax ovale malariae RBC + > 40 % 2 % 2 % 1 % RBC Ring Trofozoite Schizont normal Maurer s spots 1, 2 / rbc with two nuclei not in peripheral blood not in peripheral blood enlarged Schüffner s dots enlarged Schüffner s dots, oval fimbriated smaller 1 / rbc 1 (2) / rbc 1 / rbc ameboid (2), 16-24 merozoites ameboid pigment (2), 8-10 merozoites band shape pigment (2), 6-8 merozoites Gametocyte crescentic rounded rounded rounded
Courtesy Tulane
Sharing Plasmodium knowlesi? White N. 2004. Sharing malarias. Lancet:1006. Singh B. et al. 2004. Lancet: 1017-1024. Monkey malaria in 120 humans in 2000-2002 in Malaysian Borneo by PCR (by microscopy P. malariae).
Plasmodium knowlesi: the fifth human malaria parasite. N. J. White. 2008. CID 46:172-173. Island of Borneo, Malaysia.
Plasmodium falciparum in thick film Courtesy U.S. Department of Health, Education and Welfare. 1960.
Plasmodium falciparum: thick film with numerous small rings.
Plasmodium falciparum: thick film with numerous rings.
Plasmodium falciparum: ring in a thick film.
Plasmodium falciparum: ring and crescentic gametocyte in a thick film.
Plasmodium falciparum: two crescentic gametocytes in a thick film.
Plasmodium falciparum in thin film Courtesy U.S. Department of Health, Education and Welfare. 1960.
Courtesy Lamy L.H.
Plasmodium falciparum: two rings and Maurer s spots in a thin film.
Plasmodium falciparum: four rings in a thin film.
Plasmodium falciparum: small young ring in a thin film.
Plasmodium falciparum: two «accolé» forms in one cell in a thin film.
Plasmodium falciparum: several rings, two in one red blood cell in a thin film.
Plasmodium falciparum: three rings in one red blood cell, ring with two nuclei, «accolé» form, two red blood cells with small rings in a thin film.
Plasmodium falciparum: numerous rings, three in one red blood cell in a thin film.
Plasmodium falciparum: numerous rings, four in one red blood cell in a thin film.
Plasmodium falciparum: numerous rings in a thin film.
Plasmodium falciparum: two small, and one «accolé-like» rings in a thin film.
Plasmodium falciparum: with very dark pigment collected in one small, dense block in a thin film.
Plasmodium falciparum: with very dark pigment collected in one small, dense block and in the process of initial chromatin division in a thin film.
Plasmodium falciparum: schizont in cord blood in a thin film.
Plasmodium falciparum: schizont with clumped pigment in peripheral blood. This is seen only in heavy infections (thin film).
Plasmodium falciparum: two rings and one gametocyte (thin film).
Plasmodium falciparum: one crescentic gametocyte, about 1.5 times diameter of erythrocyte in length (thin film).
Plasmodium falciparum: two crescentic gametocytes (thin film).
Plasmodium vivax in thin film Courtesy U.S. Department of Health, Education and Welfare. 1960.
Courtesy Lamy L.H.
Plasmodium vivax: ring with Schüffner s stippling (thick film).
Plasmodium vivax: trophozoite with Schüffner s stippling (thick film).
Plasmodium vivax: young schizont, ameboid trophozoites and rings (thin film).
Plasmodium vivax: older ring and ameboid trophozoite (thin film).
Plasmodium vivax: older ring and ameboid trophozoite both with Schüffner s stippling (thin film).
Plasmodium vivax: three ameboid trophozoites in a thin film.
Plasmodium vivax: ameboid (vivax) trophozoite (thin film).
Plasmodium vivax: ameboid trophozoite, gametocyte and Schüffner s dots (thin film).
Plasmodium vivax: gametocyte (thin film).
Plasmodium vivax: three gametocytes (thin film).
Plasmodium vivax: schizont with many merozoites in an enlarged red blood cell (thin film).
Plasmodium vivax: schizont with many merozoites (thin film).
Plasmodium vivax: schizont with many merozoites (thin film).
Plasmodium vivax: mature schizont with many (19) merozoites (thin film).
Plasmodium vivax: disrupted schizont with many merozoites (thin film).
Plasmodium vivax: disrupted schizont (thin film).
Plasmodium ovale in thin film Courtesy U.S. Department of Health, Education and Welfare. 1960.
Courtesy Lamy L.H.
Plasmodium ovale: ring with Schüffner s stippling (thick film).
Plasmodium ovale: young schizont with Schüffner s stippling (thick film).
Plasmodium ovale: ring (thin film).
Plasmodium ovale: ring in a rocket shaped cell (thin film).
Plasmodium ovale: enlarged oval red cell with one ring (thin film).
Plasmodium ovale: fimbriated red cell with one ring (thin film).
Plasmodium ovale: fimbriated oval red cell with one ring (thin film).
Plasmodium ovale: two rings in one cell (thin film).
Plasmodium ovale: fimbriated and enlarged oval red cell with one young trophozoite (thin film).
Plasmodium ovale: trophozoite (thin film).
Plasmodium ovale: trophozoite in a fimbriated red blood cell (thin film).
Plasmodium ovale: two ameboid trophozoites in fimbriated cells (thin film).
Plasmodium ovale: trophozoite in a fimbriated red blood cell (thin film).
Plasmodium ovale: gametocyte (thin film).
Plasmodium ovale: gametocyte (thin film).
Plasmodium ovale: one gametocyte and two trophozoites (thin film).
Plasmodium ovale: young schizont with two nuclei (thin film).
Plasmodium ovale: young schizont with three nuclei (thin film).
Plasmodium ovale: enlarged cell with schizont with seven merozoites and black pigment (thin film).
Plasmodium malariae in thin film Courtesy U.S. Department of Health, Education and Welfare. 1960.
Courtesy Lamy L.H.
Plasmodium malariae: ring (thin film).
Plasmodium malariae: upper compact ring with black pigment and lower small ring (thin film).
Plasmodium malariae: young trophozoites with black pigment (thin film).
Plasmodium malariae: trophozoite with black pigment (thin film).
Plasmodium malariae: band shaped trophozoites (thin film).
Plasmodium malariae: band shaped trophozoite (thin film).
Plasmodium malariae: gametocyte (thin film).
Plasmodium malariae: gametocyte (thin film).
Plasmodium malariae: mature schizont in «marguerite form» with central black pigment (thin film).
Plasmodium malariae: mature schizont in «marguerite form» (thin film).
Malaria pigment (thin film). With heavy infections malaria pigment can be phagocytized by the leukocytes. Lawrence C. The Lancet, 1999, 353, 1852.
Plasmodium falciparum: in older blood exflagellation can sometimes be observed (thin film).
Babesia divergens (thin film). In the US ticks transmit Borrelia spp., Ehrlichia spp., and Babesia spp., and... Immunocompromised patients (asplenic). Generally low parasitemia. Microscopy (tetrad, Maltese cross), serology, molecular methods.
Babesia divergens (thin film). Over 100 Babesia spp. Babesia microti (NE and MW US). WA1 (Washington) related to canine B. gibsoni. Bovine Babesia divergens (Europe) and related MO1 (Missouri).
Babesia microti: the trophozoites are variable in size (thin film, PCR confirmed).
Babesia microti: multiply infected erythrocyte (thin film, PCR confirmed).
Babesia microti: extracellular trophozoites are common (thin film, PCR confirmed).
Borrelia duttoni (thin film).
Borrelia duttoni: are sometimes very slender (thick film).
Leishmania sp. Ovoid small (2-6 μm) parasites in a bone marrow aspirate. The typical rod shaped kinetoplast is seen beside the nucleus (May-Grünwald-Giemsa stain).
Trypanosoma brucei gambiense: kinetoplast, nucleus, and flagellum (thin film).
Trypanosoma cruzi: prominent kinetoplast, nucleus and flagellum (thin film).
Microfilariae that can be seen in peripheral blood in Congo-Kinshasa, according to J. Sonnet and J. Vandepitte. Mansonella perstans Loa loa Wuchereria bancrofti Periodicity day/night day night Vector flies (Culicoides spp.) flies (Chrysops spp.) mosquitoes (Culex, Anopheles, ) Size < 200 µm > 250 (230) µm > 250 µm Tail terminal nuclei terminal nuclei no terminal nuclei Sheath no yes (not stained by Giemsa) yes (slightly stained by Giemsa)
Mansonella perstans and Loa loa. Loa loa is distinctly longer and thicker than M. perstans. In the thick film the microfilaria of Loa loa show irregular coiling. The sheath does not stain with Giemsa (thick film stained with Giemsa).
2 Plasmodium? 3 Plasmodium? 4 Plasmodium? 5 Plasmodium? Courtesy Gentilini M. & Duflo B.
2 Plasmodium vivax 3 Plasmodium falciparum 4 Plasmodium malariae 5 Plasmodium ovale Courtesy Gentilini M. & Duflo B.
Comments mainly based on the Manual for the Microscopical Diagnosis of Malaria in Man 1960 Edition U.S. Department of Health, Education, and Welfare Public Health Service