The Brazilian NAT HIV, HCV, and HBV kit is an automated NAT system suitable for routine blood donor screening in a completely traceable process. The analytical sensitivity as well as the diagnostic sensitivity fulfilled all requirements set by the health ministry for blood donor screening. A significant number of transmission cases were prevented by the implementation of this important program.
Background
Malaria can be transmitted by blood transfusion through donations collected from asymptomatic donors. Transfusion-transmitted malaria (TTM) poses a great risk to blood services worldwide. A good screening tool for Plasmodium spp. detection in blood banks must have a high sensitivity for prevention of TTM. However, in Brazilian blood banks, screening for malaria still relies on microscopy.
Methods
In Brazil, screening for human immunodeficiency virus type 1 (HIV), RNA/DNA for hepatitis C (HCV) and hepatitis B (HBV) viruses is mandatory for every blood donation and uses nucleic acid amplification testing (NAT). The aim of this study was to evaluate the inclusion of an assay for malaria to identify Plasmodium sp. from total nucleic acid (TNA; DNA/RNA) by targeting the 18S rRNA gene of the parasite.
Results
Considering the limitations of microscopy and the wide availability of the Brazilian NAT platform in the screening of blood units for HIV, HCV, and HBV, a molecular diagnostic tool was validated for detection of Plasmodium sp. in blood banks; a pilot study showed that using this novel NAT assay could reduce the risk of TTM.
Conclusion
The prototype HIV/HCV/HBV/malaria NAT assay was effective in detecting infected candidate donors and has good prospects to be applied in routine screening for preventing TTM.
Although the predilection for Toxoplasma gondii to form cysts in the nervous system and skeletal and heart muscles has been described for more than fifty years, skeletal muscle cells (SkMCs) have not been explored as a host cell type to study the Toxoplasma-host cell interaction and investigate the intracellular development of the parasite. Morphological aspects of the initial events in the Toxoplasma-SkMC interaction were analysed and suggest that there are different processes of protozoan adhesion and invasion and of the subsequent fate of the parasite inside the parasitophorous vacuole (PV). Using scanning electron microscopy,Toxoplasma tachyzoites from the mouse-virulent RH strain were found to be attached to SkMCs by the anterior or posterior region of the body, with or without expansion of the SkMC membrane. This suggests that different types of parasite internalization occurred. Asynchronous multiplication and differentiation of T. gondii were observed. Importantly, intracellular parasites were seen to display high amounts of amylopectin granules in their cytoplasm, indicating that tachyzoites of the RH strain were able to differentiate spontaneously into bradyzoites in SkMCs. This stage conversion occurred in approximately 3% of the PVs. This is particularly intriguing as tachyzoites of virulent Toxoplasma strains are not thought to be prone to cyst formation. We discuss whether biological differences in host cells are crucial to Toxoplasma stage conversion and suggest that important questions concerning the host cell type and its relevance in Toxoplasma differentiation are still unanswered.
The potential for transfusion transmission of dengue virus (DENV), chikungunya virus (CHIKV), and Zika virus (ZIKV) has raised concerns about the safety of the blood supply in endemic areas. In this study, nucleic acid testing (NAT) for ZIKV, DENV, and CHIKV RNA was performed in asymptomatic blood donor samples in the city of Campinas, located in the southeast region of Brazil (1962Brazil ( in 2015Brazil ( and 1775Brazil ( in 2016. The prevalence of reactive NAT was 0.15% in 2015 and 0.62% in 2016 for dengue, 0.05% in 2015 and 0.17% in 2016 for Zika, and 0% in both years for chikungunya. These results demonstrate the weakness of the clinical interview in screening these blood donors. Furthermore, positivity for ZIKV was detected in March 2015, 1 year before the first reported cases in the region. These data attest the feasibility of using donor samples held in library as a tool for retrospective epidemiological evaluation, which is particularly interesting considering emerging pathogens, for which data on their spread and penetrance are initially scarce.
This test performance study (TPS) was carried out on DNA samples from grapevine, clematis, fungi and bacteria to compare and validate loop‐mediated isothermal amplification (LAMP) tests for detection of Grapevine flavescence dorée phytoplasma and ‘Candidatus Phytoplasma solani’ (Grapevine Bois noir phytoplasma). Two LAMP tests, for Grapevine flavescence dorée phytoplasma and ‘Candidatus Phytoplasma solani’ (as developed by Kogovšek and colleagues), with proven applicability for rapid laboratory or on‐site detection were included in this study. They were performed in 10 laboratories. In addition, the commercial Qualiplante/Hyris isothermal amplification test for Grapevine flavescence dorée phytoplasma was performed in three laboratories. The accuracy of the three tests was shown to be over 98%. Moreover, the high accuracy of these tests, which used different devices across different laboratories, confirmed their reproducibility.
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