This is a case of probable transmission of ZIKV through blood transfusion. The patient had been transfused with the blood product from an infected donor, most likely in the incubation period after ZIKV infection but prior to clinical disease onset. This report emphasizes the importance of postdonation information and recipient investigations during outbreaks of potentially blood-borne infections.

The deformability of erythrocytes is a critical determinant of blood flow in microcirculation. By capturing red blood cells (RBC) with optical tweezers and dragging them through a viscous fluid we were able to measure their overall elasticity. We measured, and compared, the RBC deformability of 15 homozygous patients (HbSS) including five patients taking hydroxyurea (HU) for at least 6 months (HbSS/HU), 10 subjects with sickle cell trait (HbAS) and 35 normal controls. Our results showed that the RBC deformability was significantly lower in haemoglobin S (HbS) subjects (HbSS and HbAS), except for HbSS/HU cells, whose deformability was similar to the normal controls. Our data showed that the laser optical tweezers technique is able to detect differences in HbS RBC from subjects taking HU, and to differentiate RBC from normal controls and HbAS, indicating that this is a very sensitive method and can be applied for detection of drug-response in sickle cell disease.

Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%). Sixteen donors (3.2%) were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.

No abstract

Red blood cell (RBC) aggregation in the blood stream is prevented by the zeta potential created by its negatively charged membrane. There are techniques, however, to decrease the zeta potential and allow cell agglutination, which are the basis of most of antigen-antibody tests used in immunohematology. We propose the use of optical tweezers to measure membrane viscosity, adhesion, zeta potential, and the double layer thickness of charges (DLT) formed around the cell in an electrolytic solution. For the membrane viscosity experiment, we trap a bead attached to RBCs and measure the force to slide one RBC over the other as a function of the velocity. Adhesion is quantified by displacing two RBCs apart until disagglutination. The DLT is measured using the force on the bead attached to a single RBC in response to an applied voltage. The zeta potential is obtained by measuring the terminal velocity after releasing the RBC from the trap at the last applied voltage. We believe that the methodology proposed here can provide information about agglutination, help to improve the tests usually performed in transfusion services, and be applied for zeta potential measurements in other samples.