Asymptomatic infections in blood donors harbouring Plasmodium: an invisible risk detected by molecular and serological tools

Transfusion-transmitted malaria due to asymptomatic Plasmodium infections is a challenge for blood banks. There is a lack of data on the prevalence of asymptomatic infected blood donors and the incidence of transfusion-transmitted malaria in low endemicity areas worldwide. We estimated the frequency of blood donors harbouring Plasmodium in an area in which asymptomatic infections have been reported. Material and methods. To estimate the frequency of blood donors harbouring Plasmodium weused microscopy and molecular tools. Serological tests were applied to measure the exposure of candidates to Plasmodium antigens. Venous blood was collected from 91 candidates attending the"Pró-Sangue" Blood Centre Foundation in São Paulo, who lived in the municipality of Juquitiba, São Paulo, Brazil, where sporadic autochthonous cases of malaria have been described. Blood samples were used for parasitological, molecular and serological studies...

PCR-RFLP assay as an option for primary HPV test

Persistent human papillomavirus (HPV) infection is an essential factor of cervical cancer. This study evaluated the analytical performance of restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) assay compared to PapilloCheck® microarray to identify human papilloma virus (HPV) in cervical cells. Three hundred and twenty-five women were analyzed. One sample was used for conventional cytology and another sample was collected using BD SurePath™ kit for HPV tests. Eighty samples (24.6%) were positive for HPV gene by PCR-Multiplex and were then submitted to PCR-RFLP and PapilloCheck® microarray. There was a genotyping agreement in 71.25% (57/80) on at least one HPV type between PCR-RFLP and PapilloCheck® microarray. In 22 samples (27.5%), the results were discordant and those samples were additionally analyzed by DNA sequencing. HPV 16 was the most prevalent HPV type found in both methods, followed by HPVs 53, 68, 18, 39, and 66 using PCR-RFLP analysis, and HPVs 39, 53, 68, 56, 31, and 66 using PapilloCheck® microarray. In the present study, a perfect agreement using Cohen's kappa (κ) was found in HPV 33 and 58 (κ=1), very good for HPV 51, and good for types 16, 18, 53, 59, 66, 68, 70, and 73. PCR-RFLP analysis identified only 25% (20/80) HPV coinfection, and PapilloCheck® microarray found 62.5% (50/80). Our Cohen's kappa results indicate that our in-house HPV genotyping testing (PCR-RFLP analysis) could be applied as a primary HPV test screening, especially in low income countries. If multiple HPV types are found in this primary test, a more descriptive test, such as PapilloCheck® microarray, could be performed.

Unexpected detection of Plasmodium vivax and Plasmodium falciparum DNA in asymptomatic blood donors: fact or artifact?

A study searching for Plasmodium vivax and Plasmodium falciparum DNA among blood donors from the non-endemic area in Brazil reported a rate of 7.41%. This number is at least three times higher than what has been observed in blood donors from the Amazon, an endemic area concentrating >99% of all malaria cases in Brazil. Moreover, the majority of the donors were supposedly infected by P. falciparum, a rare finding both in men and anophelines from the Atlantic forest. These findings shall be taken with caution since they disagree with several publications in the literature and possibly overestimate the actual risk of malaria transmission by blood transfusion in São Paulo city...