Malaria is a disease caused by the intracellular protozoan parasite Plasmodium. The female of Anopheles mosquito bites the human and spreads the parasite, however, it is possible to transmit malaria with blood transfusion. The goal of this case report is to describe an asymptomatic infected malaria blood donor in a non-endemic area in South Brazil.

This study was approved by the Nossa Senhora da Conceição ethics and research committee, number 7.243.233. Data analyzed from the period of May 2023 util November 2024 for blood donors tested for malaria (NAT PLUS HIV/HBV/HCV/Malaria Bio-Manguinhos kit). The implementation of NAT malaria began in May 2023 at the Hospital Nossa Senhora da Conceição in Porto Alegre, Brazil. Until now 27,204 donors tested for malaria by 2024 November. On March 12, 2024, a blood male donor, a 43-year-old, driver, performed a blood donation at the Blood Bank at Nossa Senhora da Conceição Hospital, Porto Alegre/ Rio Grande do Sul, Brazil. Nucleic acid amplification testing (NAT) was negative for HIV, HBV, and HCV, however, malaria was detected with a result of 29.23 (cut off 40.00). The blood donor did not present a previous history of transfusion and did not mention any travel to malaria-endemic zones. To confirm the result of the NAT Malaria test, the blood donor was called to collect a new blood sample to perform a Malaria test in a reference center to confirm the result of NAT Malaria. Malaria is an endemic public health problem, besides mosquito-human transmission, which is the most malaria-related, the transfusion-transmitted malaria (TTM) is an alert to blood bank services. Considering a previous study that showed the presence of Plasmodium spp. was observed on red blood cell components at 4 °C with a long time of storage (more than 28 days), NAT Malaria is important to transfusion security concern to TTM. Epidemiological studies have shown the importance of malaria in endemic and non-endemic regions. Malaria screening using molecular tests is an important tool in preventing the transmission of the pathogen via transfusion, impacting directly on increasing transfusion safety.

NAT-based assay for Malaria improves the surveillance system and prevents transfusion- transmitted malaria in blood banks in endemic and non-endemic areas. The NAT assay for malaria was effective in detecting infected donor candidates and has good prospects for application in routine screening, complementing the donor interview in clinical screening.