Abstract
Abstract
Background
Microscopy continues to be the mainstay for the evaluation of parasitaemia in malaria but requires laboratory support and microbiological experience. Other fast and simple methods are necessary.
Methods
A retrospective observational study of imported malaria treated from July-2007 to December-2020 was carried out to evaluate the association between the degree of parasitaemia and both rapid diagnostic tests (RDT) reactivity patterns and haematological parameters. Plasmodium falciparum monoinfections diagnosed by peripheral blood smear and/or polymerase chain reaction (PCR),which also had a positive RDT result in the same blood sample, were included in the study.
Results
A total of 273 patients were included. Most of them were male (n = 256; 93.8%) and visiting friends and relatives (VFR) travellers (n = 252; 92.3%). Patients with plasmodial lactate dehydrogenase (pLDH) or aldolase and histidine-rich protein 2 (HRP-2) co-reactivity (Pan/Pf pattern) had a parasitaemia range between 0 and 37% while those with just HRP-2 reactivity (P. falciparum pattern) had ranges between 0 and 1%. Not a single case of P. falciparum pattern was found for parasitaemia ranges greater than 1%, showing a negative predictive value of 100% for high parasitaemia. All the correlations between haematological parameters and parasitaemia resulted to be weak, with a maximum rho coefficient of -0.35 for lymphocytes and platelets, and of 0.40 for neutrophils-to-lymphocytes count ratio. Multivariate predictive models were constructed reflecting a poor predictive capacity.
Conclusions
The reactivity pattern of RDT allows a rapid semi-quantitative assessment of P. falciparum parasitaemia in travellers with imported malaria, discriminating patients with lower parasite loads. Haematological parameters were not able to estimate parasitaemia with sufficient precision.
Funder
Instituto de Salud Carlos III
Red de Investigación Cooperativa en Enfermedades Tropicales
Publisher
Springer Science and Business Media LLC
Subject
Infectious Diseases,Parasitology
Reference47 articles.
1. WHO. World malaria report 2022. Geneva, World Health Organization; 2022. Available from: https://apps.who.int/iris/handle/10665/365169.
2. Angelo KM, Libman M, Caumes E, Hamer DH, Kain KC, et al. Malaria after international travel: a GeoSentinel analysis, 2003–2016. Malar J. 2017;16:293.
3. Grobusch MP, Weld L, Goorhuis A, Hamer DH, Schunk M, Jordan S, et al. Travel-related infections presenting in Europe: A 20-year analysis of EuroTravNet surveillance data. Lancet Reg Health Eur. 2020;1: 100001.
4. Pousibet-Puerto J, Lozano-Serrano AB, Soriano-Pérez MJ, Vázquez-Villegas J, Giménez-López MJ, Cabeza-Barrera MI, et al. Migration-associated malaria from Africa in southern Spain. Parasit Vectors. 2021;14:240.
5. European Centre for Disease Prevention and Control. Malaria. In: ECDC Annual epidemiological report for 2019. Stockholm: ECDC; 2021. https://www.ecdc.europa.eu/en/publications-data/malaria-annual-epidemiological-report-2019.