Cytomegalovirus Acquisition Research Articles

Cytomegalovirus Is Not an Occupational Risk for Nurses in Renal Transplant and Neonatal Units

The risk of inpatient-to-nurse transmission of cytomegalovirus (CMV) was assessed in a five-year prospective seroepidemiologic study. We enrolled 263 renal transplant/hemodialysis nurses, 204 neonatal intensive care nurses, 225 student nurses, and 251 blood donor controls. Prevalence of CMV antibody in these 943 subjects was 33.7% and did not differ significantly among the four study groups. Sixteen subjects experienced primary CMV infections. The yearly seroconversion rate, calculated from age-related seroprevalence data, was 1.9%. The rate of seroconversion during the study, established by observing 519 seronegative subjects for 10 420 person-months, was 1.84% per year and did not differ significantly among the study groups. The proportions of patients with CMV infection (1.1% to 11.9%) and disease (0.5% to 3.4%) on study wards were not related to seroconversion in the nurses. The slow rate of acquisition of CMV in susceptible adults suggests that transmission requires prolonged, intimate contact. Nurses and nursing students who practice good personal hygiene are no more likely to acquire CMV than their peers in the community.

Increased rate of cytomegalovirus infection among parents of children attending day-care centers.

We screened parents of children from three previously studied day-care centers where children have maintained high rates of cytomegalovirus (CMV) excretion, as well as parents of children not in day-care centers (controls), for antibody to CMV. Longitudinal serologic follow-up of seronegative parents revealed that 14 of 67 with children in the day-care centers acquired CMV, as compared with none of 31 controls (P less than 0.003). All 14 parents who seroconverted had a child who was shedding CMV in saliva or urine. Among the day-care group, acquisition of CMV occurred in 14 of 46 parents of children who shed CMV, as compared with none of 21 whose children did not excrete the virus (P less than 0.0001). There was no correlation between parental seroconversion and sex, race, age, number of years of education, marital status, occupation, or number of children in the home. CMV infection occurred in 9 of 20 parents (45 percent) with a child shedding CMV who was 18 months of age or less at enrollment. We conclude that children often transmit CMV to parents and could be an important source of maternal CMV infection during pregnancy.

The epidemiology of cytomegaloviral infection in women attending a sexually transmitted disease clinic.

To test the hypothesis that cytomegalovirus (CMV) is sexually transmitted, we examined the association of CMV infection with indices of sexual activity in 347 women attending a sexually transmitted disease (STD) clinic. Stepwise multivariate logistic regression analysis showed that seropositivity to CMV (complement-fixation antibody titer, greater than or equal to 1:8) was most closely associated with number of sex partners in the subjects' lifetime (P less than .0001), young age at first sexual intercourse (P = .0002), and nonwhite race (P = .0007). Among seropositive women, cervical shedding of CMV was most strongly associated with younger age (P = .0001) and the presence of cervical chlamydial infection (P = .016). Among 84 seronegative women followed up for a mean of 18.4 weeks, 11 (13%) developed primary CMV infections, an annual incidence of 37%. Sexual contact seems to be an important mode of acquisition of CMV in some young women.

Epidemiology of cytomegaloviral infections: recommendations for prevention and control.

Cytomegalovirus (CMV) causes serious illness in immunocompromised patients and congenitally infected neonates. Knowledge of the epidemiologic characteristics of CMV remains limited, but specific and practical measures can help prevent the transmission of infection to persons in high-risk groups. Good personal hygiene, especially hand washing, is the most effective means of preventing the acquisition of CMV by pregnant women and by individuals who care for children and immunocompromised patients. Screening programs for the identification of seronegative pregnant women and female hospital employees or of asymptomatic children who are excreting CMV are not practical or beneficial; educational programs are recommended instead. Since CMV infection is endemic in the community, exclusion of known CMV excretors from schools is not indicated. Exposure of premature infants or of organ transplant recipients and other severely immunocompromised patients to exogenous sources of CMV, such as blood transfusions, should be minimized. These recommendations may need to be revised in the future as more specific knowledge of the epidemiology of CMV is gained.

Acquisition of cytomegaloviral infections in families with young children: a serological study.

Acquisition of cytomegalovirus (CMV) infection in families with young children was investigated with serial serological tests for antibody to CMV by using ELISA and anti-complement immunoflourescence. Members of 68 Houston families were studied for a mean of 3.5 years. Seroconversion occurred in one or more members of 37 (53%) of 68 families studied. The mean annual seroconversion rate was 10% for fathers, 10.6% for mothers, and 10.3% for children. The attack rate for susceptible family members (including the index case) was 54%. The index case was the child in 10 instances, the father in 2, and the mother in 2. The index case could not be identified in 23 families. This Houston study indicates that the family with young children is a high-risk setting for CMV infection. This is an important concern regarding risks for mothers in their childbearing and child-rearing years.

1045 TRANSMISSION OF CYTOMEGALOVIRUS WITHIN A LARGE NEONATAL INTENSIVE CARE NURSERY

Acquired cytomegalovirus (CMV) infections are associated with significant morbidity and mortality for very low birthweight (LEW) infants, <1300gm, and infant-to-infant transmission has apparently occurred. Therefore, CMV acquisition by all infants hospitalized over 30 days was prospectively studied in a 60-bed neonatal intensive care nursery for 24 months. All newborn urines were cultured for CMV at birth and weekly until discharge. Sera from all LEW infants were assayed for IgG against CMV(EIA). All LEW infants lacking IgG against CMV (seronegative) received blood products from seronegative donors. Of 87 LEW infants born with IgG against CMV (seropositive), 7 acquired CMV while hospitalized. Of 71 LEW seronegative infants none acquired CMV (p<0.01 compared to seropositive infants). Infants with CMV viruria received no special isolation proceedures. No infant acquiring CMV received breast milk. EcoRI digestion of the DMAs of 13 CMV isolates from infants (acquired and congenital) during the last year showed no identical isolates. These results prove that transmission of CMV from infant to infant within a large neonatal intensive care unit occurs without significant frequency.

Cytomegalovirus vaccine: persistence of humoral immunity following immunization of renal transplant candidates

A randomized, placebo-controlled, double-blind trial of Towne live, attenuated cytomegalovirus (CMV) vaccine in renal transplant candidates underway since January 1979 has enabled us to assess the durability of humoral immunity after immunization. Among 53 seronegative subjects, Towne vaccine elicited a geometric mean indirect immunofluorescent (IF) antibody titre of 72.3, but titres in patients either not transplanted or given kidneys from seronegative donors declined substantially by one year postimmunization. Vaccine boosted the geometric mean IF antibody titre in 21 seropositive untransplanted subjects from 66.5 pre-immunization to 91.0 approximately three months later. Seventeen seronegative subjects given a seropositive kidney and 27 subjects seropositive before immunization experienced a sharp boost in geometric mean antibody titre post-transplant signifying reactivation of their own CMV strain or acquisition of virus from the donor kidney. These data indicate that Towne vaccine is immunogenic in renal transplant candidates but does not completely prevent posttransplant infections.

Increased Frequency of Cytomegalovirus Infection in Children in Group Day Care

The prevalence of cytomegalovirus (CMV) infection in 103 children attending a single day care center was compared with that of 62 children kept at home. Demographic features of the day care group were similar to those of the home care group; in both groups, most of the children were white, were from middle-income families with two or fewer children, and had parents with 15 or more years of education. Ten of 57 (18%) children in home care had serum antibody to cytomegalovirus (CMV) and 2/25 (8%) had viruria. In contrast, 59/103 (57%) of children from the day care center were shedding CMV in urine or saliva. Although less than 10% of infants aged less than 1 year were excreting CMV, 78% of infants studied between 12 and 18 months of age had CMV isolated from a saliva or urine specimen. Group day care appears likely to result in early acquisition of CMV. Excretion of CMV by children in day care centers could result in transmission of the virus to susceptible day care workers or mothers, with the potential risk of fetal infection.

The Prevalence of Cytomegalovirus Viruria among Hospitalized Children and the Risk of Cytomegalovirus Acquisition by Nurses

The Prevalence of Cytomegalovirus Viruria among Hospitalized Children and the Risk of Cytomegalovirus Acquisition by Nurses

Transfusion-associated cytomegalovirus infections.

The role of blood and blood products in the acquisition of cytomegalovirus (CMV) infections following transfusion is reviewed. Considerable circumstantial data strongly suggest that primary infection and reactivation or reinfection with CMV occur frequently after transfusion. The incidence of these infections appears related both to the number of donors and to the volume of blood received by a patient. CMV infection following transfusion is most likely secondary to reactivation of latent virus either in donor white blood cells or host tissues. Recent studies of neonatal CMV infections acquired following transfusion proved that blood donors with antibodies to CMV (seropositive) are the source of CMV infection for patients lacking antibodies to CMV (seronegative). These primary CMV infections can be prevented by using only blood products from seronegative donors. Most CMV infections acquired after transfusion are either asymptomatic or characterized by a self-limited infectious mononucleosis syndrome. There are, however, specific groups of patients for whom a primary CMV infection after transfusion may cause significant morbidity and/or mortality. The patients at risk are seronegative and include pregnant women, premature infants, recipients of organ transplants from seronegative donors, and limited groups of severely immunosuppressed oncology patients. Current data suggest that for these seronegative patients the use of blood products from seronegative donors is both appropriate and likely to prevent posttransfusion CMV infection.

Cytomegalovirus infections in neonates acquired by blood transfusions.

One hundred seventy-eight newborns were cultured for cytomegalovirus (CMV) on admission and weekly after 4 weeks of age until discharge. Eight (all with birth weights of 1050 g or less) acquired CMV while hospitalized. At least seven of the infected infants were born to CMV-seronegative mothers. The risk for seronegative infants weighing less than 1250 g of acquiring CMV was 24%. There was no correlation between duration of hospitalization and birth weight for infants hospitalized over 30 days. There was a significant correlation (P less than 0.0001) between the number of blood donors for an infant and the acquisition of CMV. Infected infants received blood from eight or more donors prior to CMV shedding. Infected low birth weight infants received blood from an average of 6.5 CMV antibody-positive donors, while uninfected low birth weight infants received blood from an average of 3.1 CMV antibody-positive donors. No infant received nonmaternal breast milk. After acquiring CMV, three infants died (only one was autopsied and had proved disseminated CMV disease), two developed hepatitis and one developed hepatosplenomegaly. These results suggest that acquired CMV infection is a significant risk to seronegative low birth weight infants who receive blood from seropositive blood donors.

1073 MOLECULAR ANALYSIS OF CYTOMEGALOVIRUS INFECTIONS IN HOSPITALIZED INFANTS

Recent studies show that 14-30% of newborn infants with prolonged hospitalizations in intensive care nurseries (ICNs) develop infections with cytomegalovirus (CMV). These infections can be associated with fever, hepatitis and pneumonia. Maternal-infant transmission at the time of birth, and acquisition of CMV through blood products appear to be the major routes of viral transmission. Although most cases of CMV infections occur sporadically in ICNs, our surveillance program has identified several clusters of 2 to 4 infants excreting CMV at the same time in one ICN. These multiple groups of infants with temporally related nosocomial CMV infections suggest that infant-infant transmission of CMV may occur. Using restriction endonuclease analyses, I have compared the DNA fragment migration patterns of the CMV isolates of infants with epidemiologically related infections. In addition, the viruses of a nosocomially infected baby and his mother who developed a primary CMV infection after the discharge home of her infant were compared. At present the analyses indicate that no 2 infants excreting CMV were infected with the same strain virus. However, the DNA digestion pattern of the mother's isolate is identical to her infant's CMV strain. These findings suggest that although nosocomially infected infants are capable of transmitting CMV to other individuals that the risk of infant-infant CMV transmission in ICNs is low with routine methods of handwashing and isolation.