Emily T. Martin

Clinical Disease in Children Associated With Newly Described Coronavirus Subtypes

OBJECTIVES. Coronaviruses cause upper respiratory illness and occasionally lower tract disease in susceptible populations. In this study we examined the prevalence of 4 human coronaviruses, including subtypes OC43, 229E, and the recently described NL63 and HKU1 in a pediatric population presenting to a childrens hospital. PATIENTS AND METHODS. Specimens collected over a 1-year period from pediatric patients presenting with acute respiratory illness were analyzed for the presence of 4 coronavirus subtypes using consensus and subtype-specific real-time reverse-transcription polymerase chain reaction assays. The demographic and clinical characteristics associated with coronavirus infection were examined retrospectively. RESULTS. Coronaviruses were detected in 66 of 1043 children. Eight, 11, 19, and 28 specimens were positive for subtypes 229E, NL63, OC43, and HKU1, respectively. Coronaviruses were detected throughout the study period; all 4 of the subtypes were present simultaneously in December. The acute clinical features were similar across subtypes. Of 32 children infected with a coronavirus as the sole respiratory pathogen, 13 had lower respiratory tract disease. Children whose only detectable respiratory virus was a coronavirus were more likely to have underlying chronic disease than were children coinfected with another respiratory virus. CONCLUSIONS. Although 4 subtypes of coronavirus were detected, the recently discovered coronavirus subtypes NL63 and HKU1 accounted for the majority of coronaviruses detected in our cohort of mostly hospitalized children with respiratory symptoms. New subtypes likely represent a substantial portion of previously unexplained respiratory illnesses.

Multiple viral respiratory pathogens in children with bronchiolitis.

Aim: The aim of the study was to describe the frequency of viral pathogens and relative frequency of co‐infections in nasal specimens obtained from young children with bronchiolitis receiving care at a childrens hospital.

A pooled analysis of the effect of condoms in preventing HSV-2 acquisition.

BACKGROUNDnThe degree of effectiveness of condom use in preventing the transmission of herpes simplex virus 2 (HSV-2) is uncertain. To address this issue, we performed a large pooled analysis.nnnMETHODSnWe identified prospective studies with individual-level condom use data and laboratory-defined HSV-2 acquisition. Six studies were identified through a review of publications through 2007: 3 candidate HSV-2 vaccine studies, an HSV-2 drug study, an observational sexually transmitted infection (STI) incidence study, and a behavioral STI intervention study. Study investigators provided us individual-level data to perform a pooled analysis. Effect of condom use was modeled using a continuous percentage of sex acts during which a condom was used and, alternatively, using absolute numbers of unprotected sex acts.nnnRESULTSnA total of 5384 HSV-2-negative people at baseline contributed 2 040 894 follow-up days; 415 persons acquired laboratory-documented HSV-2 during follow-up. Consistent condom users (used 100% of the time) had a 30% lower risk of HSV-2 acquisition compared with those who never used condoms (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.40-0.94) (P = .01). Risk for HSV-2 acquisition increased steadily and significantly with each unprotected sex act (HR, 1.16; 95% CI, 1.08-1.25) (P < .001). Condom effectiveness did not vary by gender.nnnCONCLUSIONSnTo our knowledge, this is the largest analysis using prospective data to assess the effect of condom use in preventing HSV-2 acquisition. Although the magnitude of protection was not as large as has been observed with other STIs, we found that condoms offer moderate protection against HSV-2 acquisition in men and women.

Epidemiology of viral respiratory tract infections in a prospective cohort of infants and toddlers attending daycare.

n Abstractn n Backgroundn The epidemiology of respiratory tract infections (RTIs) in a daycare cohort has not been explored using molecular techniques.n n n Objectivesn (1) Determine the overall incidence of RTIs in a daycare cohort using real-time reverse transcriptase polymerase chain reaction (RT-PCR). (2) Determine the relative incidence and impact of specific respiratory viruses, and characterize and compare clinical features associated with these pathogens.n n n Study designn In this prospective cohort study conducted from February 2006 to April 2008, nasal swabs were obtained from symptomatic children ages 0–30 months enrolled in fulltime daycare.n RT-PCR was performed to detect respiratory syncytial virus (RSV), human metapneumovirus (MPV), influenza (Flu) viruses A and B, parainfluenza (PIV), adenovirus (AdV), human coronaviruses (CoV) and rhinovirus (RhV). Symptom diaries were completed for each illness.n n n Resultsn We followed 119 children (mean age 10 months; range 2–24 months) for 115 child years. The mean annual incidence of RTI per child was 4.2 the first year and 1.2 the second year of the study. At least 1 virus was identified in 67% RTIs. Co-infections were common (27% RTIs), with RhV, CoV, and AdV the most common co-pathogens. PIV was identified in 12% of RTIs with a high incidence of PIV4. The viruses with the greatest impact on our population were RSV, RhV and AdV.n n n Conclusionsn Using molecular techniques, viruses were identified in approximately twice as many RTIs as previously reported in a daycare cohort. Infections with newly identified viruses, such as HMPV and CoV subtypes were less frequent and severe than infections with RSV, AdV and RhV.n n

Clinical disease and viral load in children infected with respiratory syncytial virus or human metapneumovirus

n Abstractn n The relationship between respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) quantity in respiratory secretions and severity of illness in children remains unclear. We assessed the effect of hMPV and RSV viral load as determined by reverse transcriptase polymerase chain reaction on disease characteristics. Data were abstracted from medical records of 418 children with RSV and 81 children with hMPV; associations were evaluated in multivariate analyses, both continuously and comparing lower versus higher viral loads. Increasing viral load in hMPV-infected children was associated with increases in presence of fever, bronchodilator use, obtaining chest radiograph, and length of hospital stay. Increasing viral load in RSV-infected children was associated with decreases in inpatient admissions, use of antibiotics, and respiratory rate. Our study has described a significant relationship between viral load and markers of disease severity for both RSV and hMPV in a large population of children evaluated for respiratory disease.n n

Influenza-Associated Morbidity in Children With Cancer

The clinical impact of influenza in children undergoing therapy for cancer is not well‐described in the literature.

Multitarget PCR for Diagnosis of Pertussis and Its Clinical Implications

ABSTRACT PCR has greatly facilitated pertussis diagnosis due to the speed, sensitivity, and specificity of this assay compared to other detection methods. Various single-target PCR assays are currently utilized, but none is universally considered to be the “gold standard.” Our aim was to assess the use of multitarget versus single-target PCR for the diagnosis of pertussis in clinical samples. PCR assays targeting insertion sequence IS481 (IS), pertussis toxin ptxA promoter region (PT), and outer membrane porin (PO), or recA (RA) were evaluated in respiratory specimens collected from 4,442 patients with suspected pertussis. The diagnosis of pertussis was confirmed in 309 (6.96%) patients by the 3-target IS-PT-PO/RA PCR versus 247 (5.56%) by the conventional single-target IS (P = 0.007). Compared to single-target IS, the three-target combination increased the proportion of positive specimens by 1.25-fold, and two-target combinations increased the proportion of positive specimens by 1.10- to 1.24-fold. In addition, nine cases of B. parapertussis infection were also confirmed by using the discriminative features of this multitarget PCR. Of the 89 culture-proven pertussis cases, 17 (19.1%) and 5 of the 16 patients (31.3%) admitted to intensive care unit would have been missed had only the single-target IS PCR been applied. Patients with mild disease (P = 0.004) and shorter hospitalization (P = 0.006) were less likely to have positive cultures. This consensus generating real-time PCR approach permits a sensitive detection, as well as an accurate species identification of the causative Bordetella pathogens for the timely management of patients.

Detection of Bocavirus in Saliva of Children with and without Respiratory Illness

ABSTRACT We evaluated saliva samples from 149 children 2 to 11 years old for human bocavirus (hBoV) DNA. hBoV was detected in saliva samples at asymptomatic enrollment in 3% (5/149) and during respiratory illness in 2% (2/106) of the cases. hBoV was detected in only 1/149 asymptomatic and 0/106 illness nasal samples.

A prospective study of parainfluenza virus type 4 infections in children attending daycare.

Studies of parainfluenza virus type 4 (PIV-4) have been limited by difficulty in culturing. We prospectively studied a cohort of 225 young children attending daycare followed for 165 child-years, using polymerase chain reaction to detect 12 viruses, including PIV-4. PIV-4 was second only to PIV-3, occurring in 9 of 87 (10%) PIV+ illnesses. PIV-4 illnesses were not more severe and not associated with a specific clinical syndrome.

Sequence-Based Methods for Identifying Epidemiologically Linked Herpes Simplex Virus Type 2 Strains

ABSTRACT Traditional methods for confirming the identity of herpes simplex virus (HSV) isolates use restriction fragment length polymorphism (RFLP). However, RFLP is less amenable to high-throughput analyses of many samples, and the extent to which small differences in RFLP patterns distinguish between different viral strains remains unclear. Viral HSV type 2 (HSV-2) DNA isolates from 14 persons experiencing a primary HSV-2 infection and from their sexual partners were analyzed by RFLP and heteroduplex mobility assays. We also compared the HSV-2 sequences from seven regions, including noncoding regions between UL19 and UL20, UL24 and UL25, UL37 and UL38, and UL41 and UL42 and coding segments of the gC, gB, and gG genes. Although the resulting RFLP patterns of the couples were almost identical, minor banding differences existed between the source and susceptible partners in five couples. Heteroduplex mobility assays were unable to distinguish between unrelated strains. Overall, 22 sites of sequence variation were found in 1,482 bp of analyzed sequence. The DNA sequences differentiated between all unrelated infections, and epidemiologically related isolates had identical sequences in all but two pairs. Our results suggest that a multilocus assay based on several DNA sequences has the potential to be an informative tool for identifying epidemiologically related HSV-2 strains.