Cytomegalovirus (CMV)

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Record number: 
Adverse Occurrence type: 
MPHO Type: 
Estimated frequency: 
CMV seropositive women shed viable virus in breast milk and this is a well recognised route of post-natal vertical CMV transmission. Transmission rates vary widely.
Time to detection: 
Symptoms within 9 days, lab confirmation within 23 days. Of note, breastfeeding started on day 3 of life and symptoms that may have been associated with CMV were described too close from the first day of exposure to breast milk. This raises the possibility of peripartum CMV infection.
Alerting signals, symptoms, evidence of occurrence: 
Day of life 9, jaundice, decreased platelets and increased C reactive protein. Day of life 23, CMV antigen test positive.
Demonstration of imputability or root cause: 
Cord blood from baby was CMV DNA negative. Mom was CMV IgG positive, IgM negative at delivery. The baby received numerous units of leukoreduced red blood cells; one of these units, which was not screened for CMV antibodies, was transfused on day 7 and retrospectively found to be CMV IgG and DNA positive. Baby became CMV IgG, IgM and DNA positive; there was response to gancyclovir treatment. CMV DNA was amplified across two variable genes, UL139 and UL146, from maternal breast milk, baby’s blood, and the repository blood sample corresponding to the transfused leukoreduced red blood cells (LR-RBC), in which CMV DNA was detected, nested PCR for the CMV UL139 gene. Homology between blood donor and baby's CMV DNA was <70% whereas baby's and mum's CMV strain sequences were 100% identical. Deep sequencing for CMV genome did not identify baby's strain in the blood donor's archive sample. This supports vertical transmission and excludes transmission through blood.
Imputability grade: 
3 Definite/Certain/Proven
Suggest new keywords: 
CMV, human breast milk, premature infant
Reference attachment: 
Suggest references: 
Sequence analysis of two variable cytomegalovirus genes for distinction between transfusion- and breast milk-transmitted infections in a very-low-birthweight infant. Yamagishi N et al. Transfusion. 2016 Jun;56(6):1305-1310
I need to do the second review, Please hold in editing status. (Ines) Carl-Ludwig: second Review on 23.09.19: I recommend to upload the reference, no changes according to review. If you want to add something: “for future consideration we should be aware that breast feeding may be associated to the risk of vertical transmission of CMV. The close contact (and/or milk) of the mother to the child may be associated to disease transmission. As the close mother-child-contact is of benefit to the premature child for other reasons it should not be recommended a risk avoiding behavior – instead CMV monitoring and awareness about this route of transmission must be trained.”; “deep sequencing for CMV genome identified 100% match to mother’s CMV genome and 66% to blood donor’s genome”
Expert comments for publication: 
Infection caused by the maternal CMV strain was demonstrated but some doubts remain as to the exact route of infection; this could have happened in utero, close to the delivery or peripartum, for example, as the symptoms linked to CMV infection were present by day 9, with breastfeeding starting on day 3 (low platelets and jaundice could also have been related to prematurity). It is also worth reminding that the value of routinely feeding fresh human milk from CMV seropositive mothers to pre-term infants outweighs the risks of transmission and clinical disease in pre-term infants; in healthy term babies, this is not an issue as babies acquire infection asymptomatically.