A Yasuda et al in the June 2003 issue of Pediatrics (1) concluded
that infants less than 34 weeks in their institutions did not seem to be
affected by the presence of CMV in breast milk. They wrote that their
results might be associated with the method of breast milk preservation.
They are correct in thinking that the method of breast milk
preservation did influence the validity and conclusions of their study.
Other authors have published results reflecting on the problems of CMV
transmission through breast milk. (2,3,4,5,6,)
Stagno et al wrote on the ability of a minus 20 degrees Celsius
environment to inactivate CMV while documenting serious neonatal CMV
infection from expressed untreated breast milk (5). Vochem et al described
that the excretion of CMV in breast milk appears as early as the end of
the first week following delivery in CMV positive mothers. (6)
In the study by A Yasuda et al, they documented that the breast milk
was positive for CMV DNA by two weeks after delivery. This slow initial
start up phase of CMV excretion protected their infants while the
preservation at minus 20 degrees Celsius following maternal discharge
afforded subsequent protection. However, even the freezing regimen may be
suspect as Dworsky et al found infectivity after a seven-day storage at
minus 20 degrees Celsius while concluding that heat treatment at 62
degrees Celsius for 30 minutes was completely protective. (2)
There are multiple factors involved in the onset of CMV infection in
the premature infant of a CMV positive mother. Gestational age, viral
load, presence of antibodies in the breast milk, etc: may be important
variables. We have seen apparent discrepancies in logic where only one of
a premature twin set developed the infection. However, we need to consider
this additional morbidity when feeding expressed breast milk to very
premature infants.
Breast milk banks per HMBANA guidelines do heat treatment on donor
breast milk as mentioned by Dworsky (2). However, there are no guidelines
or recommendations from professional societies for other sites using
mother’s own expressed breast milk. The study conditions by A Yasuda et al
include variables that protected their infants. Neonatal CMV infection in
the small premature infant can be a fatal or debilitating disease.
1. Ayako Yasuda, Hiroshi Kimura, Masahiro Hayakawa, Makoto Ohshiro,
Yuichi Kato, Onrai Matsuura, Chizuko Suzuki, and Tsuneo Morishima.
Evaluation of Cytomegalovirus Infections Transmitted via Breast Milk in
Preterm Infants With a Real-Time Polymerase Chain Reaction Assay.
Pediatrics 2003; 111: 1333-1336
2. Dworsky M, Stagno S, Pass R, Cassady G, Alford C. Persistence of
cytomegalovirus in human milk after storage. J Pediatr. 1982;101:440-43
3. Dworsky M, Yow M, Stagno S, Pass R, Alford C. Cytomegalovirus
infection of breast milk and transmission in infancy. Pediatrics.
1983;72:295-99
4. Jun W, Ze-yuan T, Yan-xing W, Wei-ru L. Acquired cytomegalovirus
infection of breast milk in infancy. Chin Med J. l 1989;102:124-28
5. Stagno S, Reynolds D, Pass R, Alford C. Breast milk and the risk
of cytomegalovirus infection. NEJM 1980;302:1073-76
6. Vochem M, Hamprecht K, Jahn G, Speer C. Transmission of
cytomegalovirus to preterm infants through breast milk. Pediatr Infect Dis
J 1998;17:53-8
HMBANA Human Milk Banking Association of North America
Other Interests: Vice President, Mother's Milk Bank at Austin
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