A case report of transfusion-transmitted Plasmodium malariae from an asymptomatic non-immune traveller.

BACKGROUND: The incidence of transfusion-transmitted malaria is very low in non-endemic countries due to strict donor selection. The optimal strategy to mitigate the risk of transfusion-transmitted malaria in non-endemic countries without unnecessary exclusion of blood donations is, however, still debated and asymptomatic carriers of Plasmodium species may still be qualified to donate blood for transfusion purposes. CASE DESCRIPTION: In April 2011, a 59-year-old Dutch woman with spiking fevers for four days was diagnosed with a Plasmodium malariae infection. The patient had never been abroad, but nine weeks before, she had received red blood cell transfusion for anaemia. The presumptive diagnosis of transfusion-transmitted quartan malaria was made and subsequently confirmed by retrospective PCR analysis of donor blood samples. The donor was a 36-year-old Dutch male who started donating blood in May 2006. His travel history outside Europe included a trip to Kenya, Tanzania and Zanzibar in 2005, to Thailand in 2006 and to Costa Rica in 2007. He only used malaria prophylaxis during his travel to Africa. The donor did not show any abnormalities upon physical examination in 2011, while laboratory examination demonstrated a thrombocytopenia of 126 × 109/L as the sole abnormal finding since 2007. Thick blood smear analysis and the Plasmodium PCR confirmed an ongoing subclinical P. malariae infection. Chloroquine therapy was started, after which the infection cleared and thrombocyte count normalized. Fourteen other recipients who received red blood cells from the involved donor were traced. None of them developed malaria symptoms. DISCUSSION: This case demonstrates that P. malariae infections in non-immune travellers may occur without symptoms and persist subclinically for years. In addition, this case shows that these infections pose a threat to transfusion safety when subclinically infected persons donate blood after their return in a non-endemic malaria region.Since thrombocytopenia was the only abnormality associated with the subclinical malaria infection in the donor, this case illustrates that an unexplained low platelet count after a visit to malaria-endemic countries may be an indicator for asymptomatic malaria even when caused by non-falciparum Plasmodium species.

Value of routine chest radiography in the diagnostic work-up of ill returned travelers.

BACKGROUND: Respiratory tract infections frequently occur in ill returned travelers, a minority of whom present with pneumonia. The most accurate and cost-effective diagnostic work-up remains an area of uncertainty. In this retrospective cohort study, the utility of routine chest radiography was evaluated. METHODS: This study was performed at the Institute for Tropical Diseases in Rotterdam and included all returned travelers in the period between 2007 and 2009 that were ill with symptoms lasting less than 1 month and had chest radiography on admission. Travelers' demographic (including travel history), clinical, and laboratory data were collected on admission and evaluated for their diagnostic power to predict radiographic evidence of a pulmonary infiltrate. RESULTS: Fifty-three (7%) of 750 ill returned travelers had radiographic evidence of a pulmonary infiltrate. Presentation with cough (odds ratio [OR] 2.80, 95% confidence interval [CI] 1.46-5.38), or elevated C-reactive protein values (OR 1.13, 95% CI 1.09-1.17), and white blood cell count (OR 1.08, 95% CI 1.05-1.17) strongly correlated with the presence of a pulmonary infiltrate. Recursive partitioning analysis identified a subset of 384 patients presenting with both cough and fever, or C-reactive protein values in excess of 23 mg/L that would optimally benefit from chest radiography. CONCLUSION: The results of this study indicate that a more judicious use of chest radiography in the routine work-up of ill returned travelers is warranted.