Volume 100, Issue 2
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Malaria, arbovirus infection and travelers’ diarrhea are among the most common etiologies of fever after a stay in the tropics. Because the initial symptoms of these diseases often overlap, the differential diagnostic remains a challenge. The aim of this study was to establish the effectiveness of platelet and leukocyte counts in the differential diagnosis of fever in the returning traveler. Between 2013 and 2016, patients with a clinical suspicion of malaria, who had thick blood smears performed were retrospectively included. The microbiological etiology of each episode was established based on molecular detection in the case of arbovirus infection, the detection of pathogens in stool samples for diarrhea and other gastrointestinal symptoms and the thick and thin blood smear results for malaria. A total of 1,218 episodes were included. Malaria, arbovirus infection, and diarrhea and other gastrointestinal symptoms caused 102 (8.4%), 68 (5.6%), and 72 (5.9%) episodes, respectively. The median platelet counts in malaria episodes were 89 × 10/L and thrombocytopenia (< 150,000 × 10 platelets/L) yielded a 98% negative predictive value to predict malaria. The median leukocyte counts in arbovirus infection episodes were 3.19 × 10/L and leucopenia (< 4 × 10 leukocytes/L) yielded a 97.9% negative predictive value to predict arbovirus infections. Platelet and leukocyte counts were not significantly altered in episodes caused by diarrhea and other gastrointestinal symptoms. Initial platelet and leukocyte counts might be useful for the clinical differential diagnosis of fever in the returning traveler. Although these results are insufficient to establish a diagnosis, they should be considered in the initial clinical assessment.


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  1. Bottieau E, Clerinx J, Van Den Enden E, Van Esbroeck M, Colebunders R, Van Gompel A, Van Den Ende J, , 2007. Fever after a stay in the tropics: diagnostic predictors of the leading tropical conditions. Medicine (Baltimore) 86: 1825. [Google Scholar]
  2. Freedman DO, Weild LH, Kozarsky PE, Fisk T, Robins R, von Sonnenburg F, Keystone JS, Pandey P, Cetron MS, GeoSentinel Surveillance Network; , 2006. Spectrum of disease and relation to place of exposure among ill returned travellers. N Engl J Med 354: 119130. [Google Scholar]
  3. Kutsuna S, Hayakawa K, Kato Y, Fujiya Y, Mawatari M, Takeshita N, Kanagawa S, Ohmagari N, , 2015. Comparison of clinical characteristics and laboratory findings of malaria, dengue, and enteric fever in returning travelers : 8-year experience at a referral center in Tokyo, Japan. J Infect Chemother 21: 272276. [Google Scholar]
  4. Wickramasinghe SN, Abdalla SH, , 2000. Blood and bone marrow changes in malaria. Baillieres Best Pract Res Clin Haematol 13: 277299. [Google Scholar]
  5. Ladhani S, Lowe B, Cole AO, Kowuondo K, Newton CR, , 2002. Changes in white blood cells and platelets in children with falciparum malaria: relationship to disease outcome. Br J Haematol 119: 839847. [Google Scholar]
  6. Kelton JG, Keystone J, Moore J, Denomme G, Tozman E, Glynn M, Neame PB, Gauldie J, Jensen J, , 1983. Immune-mediated thrombocytopenia of malaria. J Clin Invest 71: 832836. [Google Scholar]
  7. Potts JA, Rothman AL, , 2009. Clinical and laboratory features that distinguish dengue from other febrile illnesses in endemic populations. Trop Med Int Health 13: 13281340. [Google Scholar]
  8. Daumas RP, Passos SR, Oliveira RV, Nogueira RM, Georg I, Marzochi KB, Brasil P, , 2013. Clinical and laboratory features that discriminate dengue from other febrile illnesses: a diagnostic accuracy study in Rio de Janeiro, Brazil. BMC Infect Dis 13: 77. [Google Scholar]
  9. Musso D, Gubler DJ, , 2016. Zika virus. Nature 11: 1020. [Google Scholar]
  10. Lee VJ, Chow A, Zheng X, Carrasco LR, Cook AR, Lye DC, Ng LC, Leo YS, , 2012. Simple clinical and laboratory predictors of chikungunya versus dengue infections in adults. PLoS Negl Trop Dis 6: e1786. [Google Scholar]
  11. Chraïbi S, Najioullah F, Bourdin C, Pegliasco J, Deligny C, Résière D, Meniane JC, , 2016. Two cases of thrombocytopenic purpura at onset of Zika virus infection. J Clin Virol 83: 6162. [Google Scholar]
  12. Steffen R, Hill DR, DuPont HL, , 2015. Traveler’s diarrhea: a clinical review. JAMA 313: 71. [Google Scholar]
  13. Okhuysen PC, , 2013. Traveler’s diarrhea due to intestinal protozoa. Clin Infect Dis 33: 110114. [Google Scholar]
  14. Azmatullah A, Qamar FN, Thaver D, Zaidi AK, Buhatta ZA, , 2015. Systematic review of the global epidemiology, clinical and laboratory profile of enteric fever. J Glob Health 5: 020407. [Google Scholar]
  15. Zboromyrska Y, Hurtado JC, Salvador P, Alvarez-Martínez MJ, Valls ME, Mas J, Marcos MA, Gascón J, Vila J, , 2014. Aetiology of traveller’s diarrhoea: evaluation of a multiplex PCR tool to detect different enteropathogens. Clin Microbiol Infect 20: O753O759. [Google Scholar]
  16. Johnson BW, Russell BJ, Lanciotti RS, , 2005. Serotype-specific detection of dengue viruses in a fourplex real-time reverse transcriptase PCR assay. J Clin Microbiol 43: 49774983. [Google Scholar]
  17. Aranda KR, Fagundes-Neto U, Scaletsky IC, , 2004. Evaluation of multiplex PCRs for diagnosis of infection with diarrheagenic Escherichia coli and Shigella spp. J Clin Microbiol 42: 58495853. [Google Scholar]
  18. Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM, Bloomfield CD, Cazzola M, Vardiman JW, , 2016. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood 127: 23912406. [Google Scholar]
  19. Thachil J, , 2017. Platelets and infections in the resource-limited countries with a focus on malaria and viral haemorrhagic fevers. Br J Haematol 177: 960970. [Google Scholar]
  20. Grynberg P, Fernandes Fontes CJ, Braga EM, , 2007. Association between particular polymorphic residues on apical membrane antigen 1 (AMA-1) and platelet levels in patients with vivax malaria. Clin Microbiol Infect 13: 10891094. [Google Scholar]
  21. Leal-Santos FA, Silva SB, Crepaldi NP, Nery AF, Martin TO, Alves-Junior ER, Fontes CJ, , 2013. Altered platelet indices as potential markers of severe and complicated malaria caused by Plasmodium vivax: a cross-sectional descriptive study. Malar J 12: 462. [Google Scholar]
  22. Gachot B, Ringwald P, , 1998. Severe malaria [article in French]. Rev Prat 48: 273278. [Google Scholar]
  23. Berens-Riha N, 2014. Evidence for significant influence of host immunity on changes in differential blood count during malaria. Malar J 13: 155. [Google Scholar]
  24. Lacerda MV, Mourão MP, Coelho HC, Santos JB, , 2011. Thrombocytopenia in malaria: who cares? Mem Inst Oswaldo Cruz 106 (Suppl 1): 5263. [Google Scholar]
  25. Lampah DA, 2015. Severe malarial thrombocytopenia: a risk factor for mortality in Papua, Indonesia. J Infect Dis 211: 623634. [Google Scholar]
  26. Khan SJ, Abbass Y, Marwat MA, , 2012. Thrombocytopenia as an indicator of malaria in adult population. Malar Res Treat 2012: 405981. [Google Scholar]
  27. Kochar DK, 2010. Thrombocytopenia in Plasmodium falciparum, Plasmodium vivax and mixed infection malaria: a study from Bikaner (northwestern India). Platelets 21: 623627. [Google Scholar]
  28. Snow RW, Guerra CA, Noor AM, Myint HY, Simon I, , 2005. The global distribution of clinical episodes of Plasmodium falciparum malaria. Nature 434: 214217. [Google Scholar]
  29. Jelinek T, 2002. Imported falciparum malaria in Europe: sentinel surveillance data from the European network on surveillance of imported infectious diseases. Clin Infect Dis 34: 572576. [Google Scholar]
  30. Pistone T, Diallo A, Mechain M, Receveur MC, Malvy D, , 2014. Epidemiology of imported malaria give support to the hypothesis of “long-term” semi-immunity to malaria in sub-Saharan African migrants living in France. Travel Med Infect Dis 12: 4853. [Google Scholar]
  31. Possas C, , 2016. Zika: what we do and do not know based on the experiences of Brazil. Epidemiol Health 38: e2016023. [Google Scholar]
  32. Duijster JW, Dutch ZIKV Study Team , 2016. Zika virus infection in 18 travellers returning from Surinam and the Dominican Republic, The Netherlands, November 2015–March 2016. Infection 44: 797802. [Google Scholar]
  33. Meltzer E, Leshem E, Lustig Y, Gottesman G, Schwartz E, , 2016. The clinical spectrum of Zika virus in returning travelers. Am J Med 129: 11261130. [Google Scholar]
  34. Leder K, GeoSentinel Surveillance Network , 2013. GeoSentinel surveillance of illness in returned travelers, 2007–2011. Ann Intern Med 158: 456468. [Google Scholar]
  35. Harvey K, Esposito DH, Han P, Kozarsky P, Freedman DO, Plier DA, Sotir MJ, Centers for Disease Control and Prevention (CDC); , 2013. Surveillance for travel-related disease—GeoSentinel Surveillance System, United States, 1997–2011. MMWR Surveill Summ 62: 123. [Google Scholar]

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  • Received : 06 Sep 2018
  • Accepted : 15 Oct 2018
  • Published online : 10 Dec 2018

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