CMV on surfaces in homes with young children: results of PCR and viral culture testing

Abstract

Background: Caring for young children is a known risk factor for cytomegalovirus (CMV) infection mainly through exposure to their saliva and urine. In a previous study, 36 CMV-seropositive children 2 mo. to 4 years old were categorized as CMV shedders (n = 23) or non-shedders (n = 13) based on detection of CMV DNA in their saliva and urine. The current study evaluated the presence of CMV on surfaces in homes of the children.

Methods: Study staff made 4 visits to homes of the 36 enrolled children over 100 days. Saliva was collected by swabbing the mouth and urine was collected on filter paper inserted into diapers. In addition, five surface specimens were collected: three in contact with children's saliva (spoon, child's cheek, washcloth) and two in contact with children's urine (diaper changing table, mother's hand). Samples were tested by PCR and viral culture to quantify the presence of CMV DNA and viable virus.

Results: A total of 654 surface samples from 36 homes were tested; 136 were CMV DNA positive, 122 of which (90%) were in homes of the children shedding CMV (p < 0.001). Saliva-associated samples were more often CMV positive with higher viral loads than urine-associated samples. The higher the CMV viral load of the child in the home, the more home surfaces that were PCR positive (p = 0.01) and viral culture positive (p = 0.05).

Conclusions: The main source for CMV on surfaces in homes was saliva from the child in the home. Higher CMV viral loads shed by children correlated with more viable virus on surfaces which could potentially contribute to viral transmission.

Keywords: Cytomegalovirus; Infectious virus; Transmission; Viral shedding.

Fig. 1

CMV PCR results on specimens collected in homes of children shedding CMV. Various specimens were collected at four follow-up visits to homes over 100 days. Children living in the homes were shedding CMV when tested at the screening visit which was prior to the first follow-up and is not shown on the graph. Colored circles signify a positive result, open circles a negative result. Blue color is for saliva and its contact surfaces, yellow is for urine and its contact surfaces. At each visit, up to seven specimens were collected, as shown to the left of the chart

Fig. 2

CMV PCR results on specimens collected in homes of children not shedding CMV. Various specimens were collected at four follow-up visits to homes over 100 days. Children living in the homes were not shedding CMV when tested at the screening visit which was prior to the first follow-up and is not shown on the graph. Colored circles signify a positive result, open circles a negative result. Blue color is for saliva and its contact surfaces, yellow is for urine and its contact surfaces. At each visit, up to seven specimens were collected, as shown to the left of the chart

Fig. 3

Viral load range for each sample type, horizontal lines represent median viral load values. Blue color is for saliva and its contact surfaces, yellow is for urine and its contact surfaces

Fig. 4

CMV PCR-positivity (%) of the six specimen types that are categorized according to the CMV viral load (low, medium, high) of the saliva from the child living in the home from which the specimens were collected. N = the total number of saliva specimens collected per category