Feasible alternatives to DBS in the retrospective diagnosis of congenital cytomegalovirus infection

BACKGROUND

Retrospective diagnosis of congenital cytomegalovirus (cCMV) infection may be challenging mainly because of the high variable sensitivity of PCR on dried blood spots (DBS) samples.

OBJECTIVES

To compare cytomegalovirus (CMV) viral load (VL) values in different samples obtained at birth from infants with cCMV infection. To evaluate dried umbilical cord (DUC) samples as an alternative to DBS.

STUDY DESIGN

Saliva and/or urine, peripheral blood (PB), and DBS from 16 infants with confirmed cCMV infection were collected at birth. CMV VL were determined by DNA extraction and real-time polymerase chain reaction (rt-PCR). In two cases, VL was determined from DUC samples.

RESULTS

Six (37.5 %) of the 16 infants were symptomatic, and 10 (62.5 %) were asymptomatic. The CMV VL found in saliva (median: 1,958,525 [IQR: 597,683-3,483,843] IU/mL) and in urine (median: 691,865 [IQR: 188,489.5-3,175,696] UI/mL) were both higher than those found in PB (median: 1115 [IQR: 364-4,002] IU/mL), p: 0.0001). Symptomatic infants presented 100 % of detectable VL in PB and 50 % in DBS. Asymptomatic infants showed 75 % of detectable VL in PB and 30 % in DBS. The VL in DUC were 22,341, 9754 IU/mL and 994 IU/mL.

CONCLUSIONS

When VL was detectable in PB, the values were lower than in saliva or urine, in both symptomatic and asymptomatic cases of cCMV. The low sensitivity in DBS samples could be due to low blood volume content, making CMV VL undetectable even when using optimised extraction and PCR protocols. In our limited experience, DUC could play a complementary diagnostic role when DBS VL is undetectable.

Enterovirus D68-associated respiratory and neurological illness in Spain, 2014-2018

During 2014, enterovirus D68 (EV-D68) outbreaks were described globally, causing severe respiratory diseases in children and, in some cases, subsequent paralysis. In this study, the type characterization of enterovirus (EV) detected in respiratory illnesses and the epidemiology and clinical association of EV-D68 infections in Spain over a five-year period were described. A total of 546 EV-positive samples from hospitalized patients with respiratory infections were included. EV-D68 was the most frequently detected type (46.6%, 191/410 typed EV). Other EV from species A (25.1%), B (27.8%) and C (0.5%) were also identified. EV-D68 infections were more associated with bronchitis while EV-A/B types were more frequent in upper respiratory illness (p < 0.01). EV-D68 was also detected in patients with neurological symptoms (nine meningitis/meningoencephalitis and eight acute flaccid paralysis cases). Phylogenetic analysis of 3′-VP1 region showed most Spanish EV-D68 sequences from 2014 to 2016 belonged to subclades B2/B3, as other American and European strains circulating during the same period. However, those detected in 2017 and 2018 clustered to the emerged subclade D1. In summary, different EV can cause respiratory infections but EV-D68 was the most prevalent, with several strains circulating in Spain at least since 2014. Association between EV-D68 infection and neurological disease was also described.