Cytomegalovirus (CMV): Common and Confusing
Saturday, September 23, 2006
Kenneth F. Trofatter, Jr., MD, PhD
CMV is the MOST common congenitally (fetal) and perinatally (newborn) acquired virus disease in humans and the single most important infectious cause of mental retardation and congenital deafness in the U.S. and other industrialized nations. CMV is a member of the herpes family and human CMV is restricted to humans with no known animal reservoir. At least 80-90% of individuals are infected with CMV during their lives, but infection may occur in the absence of overt disease or the recognition that an illness is the result of CMV. As with other herpes viruses, once an individual is infected with CMV, periodic 'recurrences' can result from reactivation of virus replication at various sites in which the virus is latently harbored in the body. Although probably not that common, secondary infections can also occur with other strains of CMV. No cross-reactive immunity is afforded by previous infections with other herpes viruses such as herpes simplex, varicella-zoster (chickenpox), or Epstein-Barr (mononucleosis) viruses.
Transmission of the virus can occur from exposure to just about any body fluid, most commonly via saliva, respiratory, and venereal routes or by contact with infected urine or breast milk. Exposure tends to occur at earlier ages in lower socioeconomic groups, promiscuous individuals, and children at day care centers. Serologic evidence (seropositivity) of infection in women during the common childbearing years (18-35) is about 50% for those in middle and upper, and 90% in lower, socioeconomic groups. Among seronegative women, the chance of infection (seroconversion) is about 1-3% per year, however, this is as high 10-20% in women who work in day care settings and 50% in women with infected children under two years of age!
Congenital infections with CMV occur in 1-2% of ALL pregnancies meaning the virus can cross the placenta with relative ease compared to other herpes and most other common virus infections. But, as we shall see later on, congenital infection rarely results in the poor outcome noted above unless the congenital infection is the result of a primary (first time) infection in the mother during the pregnancy. Neonatal infections are commonly acquired by exposure to an infected genitourinary tract during delivery, breast milk, and saliva of family members. Infection of the newborn rarely has the serious consequences that are seen with congenital infections resulting from primary maternal disease during the pregnancy. Serious but, generally not life-threatening, neonatal infections can result under the rare situation in which primary maternal infection occurs late in the pregnancy and delivery occurs before the mother has developed immunity to the virus that could be passed along to the fetus in utero.
As a baseline, a relatively constant percentage (10-15%) of seropositive women is found to be excreting CMV from the urinary tract at any given time. The incidence of excretion tends to increase throughout pregnancy with cervical rates in the third trimester as high as 35-40%! Overall, among seronegative women, there is about a 0.5-1% risk of a primary CMV infection in each pregnancy, although this is much higher in 'at risk' groups such as day care workers, health care providers, and women with young children. Pregnancy does not appear to increase the risk of contracting CMV, nor does it place the woman at greater risk for more severe primary infections. There is some evidence though that women who do develop more severe infections (CMV mononucleosis) and those women with asymptomatic infections who are at greatest risk for transmitting the virus to their babies have qualitatively different antibody responses to CMV than women who do not.
In the next post we will look at the spectrum of maternal and fetal disease caused by CMV...
26 Comments:
At Fri Oct 19, 02:27:00 PM 2007,
cassidy mcfarland said…
I am a mother who has recently suffered the loss of a child who suffered severely from problem due to congential cmv. I was infected with the virus during my pregnancy but was unaware of it. The virus is so terrible that it caused my son to have a CVA during utero and my son suffered from being deaf, blind and he also had torticolis. I am very interested in this nasty virus, any more information that you put up here is deffinately well needed and well appreciated. Do you know any good sites to do more research on the virus?
At Mon Oct 22, 04:35:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
Hi Cassidy: I am so sorry for your son's problems. It is truly a devastating virus when you catch it for the first time during pregnancy. Many folks do not even know they have gotten the infection. The Center for Disease Control has a very informative site on CMV. You can get to it by following this link: http://www.cdc.gov/cmv/
Fortunately, it is VERY unlikely another child of yours will be affected in this way, so best of luck and thank you for reading. Dr T
At Thu Nov 15, 05:59:00 PM 2007,
Anonymous said…
I have had reoccurring miscarriages and my OB did a TORCH? blood test which showed my CMV levels were slightly elevated. I’m supposed to go back in two weeks for another test to recheck the levels. Could this virus have caused my miscarriages? Is there a period of time I should wait before trying to conceive again? If I do become pregnant again am I at risk of having a baby affected by CMV?
At Sun Nov 18, 07:30:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Nov 15: I devoted a full reprise post to CMV because of your interest today, November 18,2007. Your questions are answered there! Thanks for reading and for the incentive to revisit this important subject! Dr T
At Fri Nov 23, 12:20:00 PM 2007,
Anonymous said…
I want to say thank you for your response. You provided me with some much needed answers.
Thanks again,
Anonymous Nov 15th
At Thu Nov 29, 04:52:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Nov 23: You are welcome. Glad I could help. Thanks again for reading! Dr T
At Mon Mar 10, 10:45:00 PM 2008,
Anonymous said…
I gave birth to three children. My middle child was born in 1985. I contracted CMV during my pregnancy with her and she was born profoundly retarded with calcifications of the brain, etc. She passed away at 9 months old and only after that, did the doctors tell me she probably wouldn't have lived to reach the age of five. The horror that I wen't through due to her death, you don't want to know. But I can tell you that the baby girl I gave birth to 2 years later is perfectly fine. Pregnant women should not touch litter boxes, change babies without washing your hands(even if it's your own) or listen to doctors when your telling them your sick and they do nothing. You are in control and if you have experienced a tragedy like I have, don't worry. You should be immune now should you get pregnant again. If you lost a child from this wicked disease, don't worry. I think they all are together with whatever God you believe in. Thanks, keep the faith, it isn't you!
At Fri Mar 14, 03:11:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Mar 10: Thank you so much for sharing your story with us. It is heart-breaking, but you have given justifiable hope to other women who are in similar circumstances. Thank you for reading and best wishes. Dr T
At Sun Mar 16, 02:44:00 AM 2008,
Anonymous said…
Hi,
I am an pediatric ICU RN and before becoming pregnant (approx. 3+ months) was assured that I was seropositive for CMV. I am now 26 weeks pregnant and just found out that one of my patients that I cared for last week (approx. 25 weeks pregnant) tested positive for CMV (he is immunocomprimised and is on Cytovene). What are the chances of my baby becoming reinfected with the disease? Should I be concerned?
Thank you!
At Fri Mar 21, 07:06:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Mar 16: Sorry it has taken so long to write. Since you are CMV positive, you are more liekely to be a source of infection of your baby (about 1-2% chance) than any CMV infected children to which you are exposed. However, since your exposure to CMV occurred prior to the pregnancy, the overwhelming odds are that your baby will be protected from the more severe manifestations of congenital CMV. You can have your baby's urine tested shortly after birth for CMV and if it is positive, then your pediatrician will usually simply follow with periodic assessment of growth, development, hearing and vision - things they follow anyway! Good luck to you and let us know how things turn out. Dr T
At Thu Apr 17, 06:46:00 PM 2008,
Anonymous said…
My daughter is a special education teacher with the severely disabled. She is 7 weeks pregnant and just learned that one of her students is CMV positive. This student contracted CMV during his mother's pregnancy and is severely mentally retarded. My daughter just received results on her CMV testing and it shows she has the antibodies or has been exposed. She goes back in 3 weeks for another blood test. Her OB/GYN has recommended she have no contact with the student or the classroom due to the fact the student drools and my daughter often has open wounds due to bites, scratches, etc. from the students. The school district is somewhat hesitant to "reassign" her to another classroom. We understand that good sanitary precautions help but are very fearful of her contracting a recurring CMV infection. Can you offer advice please???? You can email me at jslone9628@aol.com thanks so much for your blog and time.
At Sun Apr 20, 06:49:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Apr 17: Your daughter probably has PRIOR immunity from her years of working in special ed and this will probably protect her baby. Many nbabies in special ed are chronic excreters of CMV. Regardless, she needs to use good handwashing techniques and should probably wear gloves when she has to handle this child. There are other strains of CMV and there is variable cross-reactive immunity. She and her baby will probably do just fine. See my comment above yours for some insight into her risks from reactivation of her own CMV. These too are small. Please let us know how things turn out. Dr T
At Wed Jul 09, 06:40:00 PM 2008,
Anonymous said…
I have been around kids a vast majority of my life. My mom ran a daycare many years ago. I then chose to be a nanny, Applied behavioral analysis provider for children 0-3, and am now a service coordinator for children with disabilities from 0-3. A coworker of mine said that she contracted CMV for the first time in her first trimester and suggests that any of us get tested to ensure that we've already had CMV. Our company makes us sign a policy stating that we're aware that we may be exposed to CMV and are not responsible for our exposure. I am a little paranoid given that I miscarried last year (for reasons I'm sure are not from CMV). I read that the tests to see if one has CMV can be inaccurate. Should I and can I assume that at some point I've already been exposed to CMV?
At Sat Jul 12, 07:57:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous July 9: I think you should have the test done. They are not inaccurate. They can tell you if you have been exposed to and therefore have CMV. Sometimes they are difficult to interpret, but if you have CMV-specific IgG, you will at least know you are immune and a baby should be protected as much as possible. Dr T
At Thu Aug 28, 04:47:00 PM 2008,
brooke said…
I am 23 weeks pregnant. I am a teacher for the Deaf. I have just found out that I have a student that contract CMV through the mom at birth. I have been tested for CMV and both tests came back negative. Is is safe for me to work with this student? Or should I have her moved? What are my chances of contracting CMV from her?
At Wed Sep 03, 05:04:00 AM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To brooke: These are such difficult questions to answer. If you use good handwashing techniques and don't exchange "body fluids" your risk is probably low, but it is NOT zero. Probably most of the children with whom you work (and at least 50% of all individuals with whom you come in contact on a regular, excrete CMV periodically and put you at risk for contracting it during a pregnancy. CMV-negative women who work in day care centers have at least a 25% chance of contracting the virus on an annual basis. So, like I said, there is no easy answer. Just wish we had a good CMV vaccine to help prevent having so many women in your situation. Good luck! Dr T
At Mon Sep 08, 11:26:00 AM 2008,
Anonymous said…
Well. I didnt know it at the time, but I used a CMV positive sperm donor. Im negative. I dont yet know if Im pregnant. Is there a chance at all that I will not get infected even though Im exposed? In other words is there a possibility I will not become infected or pass it on?
At Tue Sep 23, 08:33:00 AM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Sept 8: Take this one step at a time. I would suggest monthly screens for CMV-specific IgG and IgM. If those turn positive, then we can discuss your other concerns. If you do not conceive this cycle, I would wait at least 2-3 months before trying again to see what your CMV status is. Best of luck to you! Dr T
At Fri Oct 17, 10:31:00 AM 2008,
Unknown said…
Hi, I am a mother of a 7 1/2 yr old son. Two years ago we found out he had CMV. It has recurred twice since. We don't know if it was congenital or where he aquired it. He also has ideopathic short stature at 44 inches tall and 37 lbs. He is on a well balanced diet and centrum vitamins daily. I have two questions. Is Hgh safe for him with CMV? and what are the chances of him developing complications such as deafness or vision loss (he complains of fuzzy vision during acute attacks of CMV)? Thank you for any info.
At Sat Oct 25, 06:51:00 AM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To unknown Oct 17: I have more questions for you than answers at this point. What led to the original diagnosis of CMV in your son? Does he have any developmental delays mentally? Has his hearing and vision been checked - for the latter, I would recommend an ophthalmologist if you are concerned that CMV could be causing vison problems. Could his small stature have been related to a congenital CMV infection? Does he have any other medical conditions? The reason I ask these questions is that his long-term prognosis depends to a large extent on whether this is though to be a congenital infection or an infection he caught in early childhood. If the latter is the case, then he, like almost everyone who contracts CMV after they are born, will probably continue to harbor the virus in his body and even have recurrences, but usually this does not seem to predictably cause long-term impairment. Best wishes and if you have answers to any of my questions, please get back in touch. Dr T
At Tue Oct 28, 10:08:00 AM 2008,
Anonymous said…
my 3 year old was recently diagnosed with mono, and my ob ordered a test for me for CMV (i am 22 weeks pregnant). the test was negative, though showed i do not have immunity. Given the long incubation time on the virus, i am wondering if i should get re-tested, but my ob says its not necessary. i would appreciate a second opinion, thanks!
At Tue Oct 28, 07:20:00 PM 2008,
Unknown said…
Dr. T, (mother of 7 1/2 yr old son)
He originally became ill in spring 2007,age 6 w 103-104 temp uncontrolled w Tylenol/Motrin for several days, body/joint aches, decreased appetite, extreme fatigue. Thru bloodwork was diagnosed with CMV. Spring 08, same s/s but with a PA in the office who prescribed amoxicillan twice before ordering tests and questioned Kawasaki (but he did not have red strawberry tongue or peeling hands/feet). Cmv was the diagnosis again. During preg, I was 95% effaced at 6 mo,confined to bed,group strep B pos.,and delivered via c sect at 37 wks. He had low blood sugar which has been borderline since. No one ever told me if it was congenital. Has had routine eye exams but not yet this year. Hearing tests at school, nothing extensive,w normal results. He is currently under evaluation for HGH but has not been ordered yet, just watching his growth pattern. He is in the top of his class and no mental delays. Has a rib hump (tilted sternum). Otherwise no further problems. Thanks again for any insight. I just want to be on top of things.
At Wed Nov 19, 02:51:00 PM 2008,
Anonymous said…
hi i am currently pregant and i have contracted cmv and dont know how or when i got it but i know i have herpes simplex virus 1 are they the same or totally different infections???i am really worried about the outcome of this pregantice but i am having faith that all will go well i am 15 weeks today and just hoping and praying that havein these 2 infections wont affect my unborn baby.can you give me some insite of both if they are the same or not?
thanks
At Wed Dec 17, 06:39:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Oct 28: Pardon my delayed response but the 'blogger' has had 'technical difficulties' and I just received your question this week. Personally, I do not see a need to be retested at this time. The simpler thing to do would be to have the baby's urine screened for CMV after delivery if you are worried about it. If the baby is positive, you will know that you had to have seroconverted (gotten the virus yourself) during the pregnancy and there will be a reason to follow the baby more closely for complications related to congenital infection. Hopefully things will be just fine! Best wishes. Dr T
At Wed Dec 17, 06:45:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Unknown Oct 28: I am curious as to why your doctors think the recurrent symptoms your child has are the result of recurrent CMV infections. That would be somewhat unusual - not the recurrences (they occur all the time), but the symptoms. Do they think he is small because of a congenital CMV infection? Did he have low blood sugar at birth because he had sepsis related to GBS? If his problems continue, I would take him to a pediatric specialist at a university medical center or a comparable facility to be more thoroughly evaluated. Best wishes! Dr T
At Wed Dec 17, 06:48:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Nov 19: They are both members of the herpesvirus family, but they are COMPLETELY different viruses. I would worry much more about a first-time CMV infection in early pregnancy than a herpes simplex virus infection. I hope you actually contracted the CMV BEFORE pregnancy and not for the first time during the pregnancy. Best wishes and let us know how things turn out! Dr T
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