Diagnosis of primary human herpesvirus 6 and 7 infections in febrile infants by polymerase chain reaction

Primary human herpesvirus 6 (HHV-6) and 7 (HHV-7) infections were identified in febrile children by qualitative and quantitative polymerase chain reaction (PCR) assays. Diagnosis was based on the differential detection of viral DNA in peripheral blood mononuclear cells (PBMC), but not in saliva. Six of 41 febrile infants, but none of seven non-febrile controls, were identified with primary infections (three HHV-6, three HHV-7). These children had significantly higher viral loads in PBMC (HHV-6, median 24213 genomes/10(6) PBMC; HHV-7, median 6,040,000 genomes/10(6) PBMC) than DNA-aemic, saliva PCR positive children (HHV-6, median 1606 genomes/10(6) PBMC, p < 0.01; HHV-7, median 7089 genomes/ 10(6) PBMC, p < 0.05). Viral DNA was detected in serum by PCR in only 50% of primary infections. All three children with primary HHV-7 infection had febrile convulsions. Thus PCR, including quantitative assays, may identify primary HHV-6 and HHV-7 infections when an appropriate combination of clinical specimens is used.     

Diagnosis of tuberculosis by polymerase chain reaction

For the diagnosis of extrapulmonary tuberculosis in adults and all forms of tubercular infections in children, microscopic and cultural techniques have (seen shown to be inadequate. Many serological techniques have been employed for non culture diagnosis of tuberculosis. Early promising results have repeatedly given way to subsequent findings of non-specificity. Major mycobacterial antigens have been shown to be heat shock proteins which are highly conserved in nature. DNA probes for tuberculosis are specific but have a sensitivity equivalent to AFB smear examination. Polymerase Chain Reaction (PCR) with its ability to selectively amplify DNA fragments of interest offers a potentially powerful technique for the rapid, specific and sensitive diagnosis of tuberculosis. Samples from partially treated patients could be culture negative but can be detected by PCR.     

Diagnosis of typhoid fever by polymerase chain reaction

Objective To determine the efficacy of nested polymerase chain reaction (PCR) in detecting Salmonella typhi gene sequences in blood and urine specimens and to determine the cut-off titer of Widal test using PCR as gold standard test for diagnosis of typhoid fever. Methods Study included 71 children between the ages of 8 months and 14 years; 52 of them were suspected cases of typhoid fever, 11 were febrile non-typhoid controls, and 8 were apparently healthy children. Nested PCR in Blood and Urine, Blood culture, Widal test and Urine culture were done and their results analyzed. Results Among suspected typhoid cases, PCR in blood and urine had positivity of 82.7% each. Blood culture, Widal test (at cut off titer TO and / or TH ≥ 1:160) and urine culture had positivity of 26.9%, 50% and 3.8% respectively. In one case, urine PCR was positive and blood PCR was negative. Similarly, in another case, PCR in blood was positive however urine tested negative. Considering PCR as gold standard, the antibody cut off titer was evaluated. A cut-off titer of TO ≥ 1:80 and/or TH ≥ 1:160 had sensitivity and specificity of 72.7% and 84.2%, while the respective figures were 50% and 89.5% when the cut-off titer was TO and/or TH ≥ 1:160. Conclusion The sensitivity, specificity, positive and negative predictive values, likelihood ratios were same for PCR based detection of S. typhi in blood and urine samples. Nested PCR had higher efficacy in detecting typhoid fever than Widal test, blood and urine cultures. A cut off titer of TO ≥ 1:80 and/or TH ≥ 1:160 was found to have better diagnostic value in this region.     

Human herpesvirus 6 infection in febrile infants ninety days of age and younger

BACKGROUND: The importance of human herpesvirus 6 (HHV-6) as a pathogen in febrile infants 相似文献   

Absence of associations between influenza-associated encephalopathy and human herpesvirus 6 or human herpesvirus 7

BACKGROUND: Influenza-associated encephalopathy is a severe complication of influenza virus infection, but its pathogenesis is unknown. It was recently suggested that the neurologic complications of influenza, including encephalopathy, are associated with human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7).AIM To confirm or refute the association between influenza-associated encephalopathy and HHV-6 or HHV-7. METHODS: Cerebrospinal fluid and serum from 25 patients with central nervous system complications of influenza (18 patients with encephalopathy and 7 patients with febrile convulsions) were investigated. The specimens were examined by real time polymerase chain reaction (PCR) and nested PCR for HHV-6 and HHV-7 DNA. RESULTS: In the cerebrospinal fluid samples neither HHV-6 DNA nor HHV-7 DNA was detected by real time PCR or nested PCR. HHV-6 DNA was detected in a single serum sample from a patient with febrile convulsions. CONCLUSION: In our study there was no association with HHV-6 or HHV-7 in most patients with central nervous system complications of influenza.     

Diagnosis of group A coxsackieviral infection using polymerase chain reaction

Aims: To examine the relation between enteroviral infection, especially group A coxsackieviral infection, and acute febrile illness over two summers using tissue culture and polymerase chain reaction (PCR). Methods: Throat swabs were collected from 246 children from June to August 1997 and 1998. Results: Enteroviruses were isolated from 33/246 samples and 35 other viruses were isolated. Enteroviral genomes were detected in 54/178 samples from which no virus was isolated. Of 41 enteroviral genotypes identified by sequence analysis of PCR products, 38 were group A coxsackieviruses, which are usually difficult to isolate using tissue culture. Conclusion: Results indicate that viral detection and identification based on PCR is useful in the diagnosis of group A coxsackieviral infection.     

Five cases of thrombocytopenia induced by primary human herpesvirus 6 infection

Abstract Five patients suffering from exanthem subitum with thrombocytopenia were confirmed as primary human herpesvirus 6 (HHV-6) infection by serological test. All cases had thrombocytopenia during the acute phase of exanthem subitum. The clinical features of these cases were benign, and all recovered without any specific treatment. Moreover. 4 of the 5 cases showed a mild elevation of hepatic transaminase during the same period, and other viral infections including cytomegalovirus, Epstein-Barr virus, and human herpesvirus 7 were ruled out in these patients. It was speculated that direct inhibition of platelet production by the virus or cytokine induced by the virus-infected cells was the mechanism of the thrombocytopenia induced by primary HHV-6 infection.     

Quantitation of human parvovirus B19 DNA by real-time polymerase chain reaction

BACKGROUND: There have been no reports on either the serial quantification of genomic copies in the various parvovirus B19 infections or the comparison of the viral amount in erythema infectiosum, unlike with that in other parvovirus B19 infections. METHODS: A total of 19 children with parvovirus B19 infection were classified into a group of seven (group A) with erythema infectiosum and a group of 12 (group B) without erythema infectiosum, and their serum levels of parvovirus B19 DNA were quantified by real-time polymerase chain reaction. A total of 30 boys and girls with some symptoms but no parvovirus B19 infection served as a control group (group C). RESULTS: The amount of parvovirus B19 DNA differed significantly between groups A and C (P < 0.01) and between groups B and C (P < 0.01). The amount of viral DNA was significantly higher in group B than in group A (P < 0.01). Sequential determination showed that the amount of viral DNA in group B rapidly decreased over several days. Erythema infectiosum developed in two patients of group B on the 6th and 29th days after onset when the amount of viral DNA was similar to that in group A. CONCLUSIONS: The amount of parvovirus B19 DNA correlated well with the stage of infection, and its quantitation was useful for determining disease status and prognosis. In parvovirus B19 infection, the viremia is associated with rare but varied pathological states different from erythema infectiosum, such as transient aplastic crisis, hemophagocytic syndrome, lupus-like syndrome, and papular-purpuric gloves and socks syndrome.     

Diagnosis of group A coxsackieviral infection using polymerase chain reaction.

AIMS: To examine the relation between enteroviral infection, especially group A coxsackieviral infection, and acute febrile illness over two summers using tissue culture and polymerase chain reaction (PCR). METHODS: Throat swabs were collected from 246 children from June to August 1997 and 1998. RESULTS: Enteroviruses were isolated from 33/246 samples and 35 other viruses were isolated. Enteroviral genomes were detected in 54/178 samples from which no virus was isolated. Of 41 enteroviral genotypes identified by sequence analysis of PCR products, 38 were group A coxsackieviruses, which are usually difficult to isolate using tissue culture. CONCLUSION: Results indicate that viral detection and identification based on PCR is useful in the diagnosis of group A coxsackieviral infection.     

Invasion by human herpesvirus 6 and human herpesvirus 7 of the central nervous system in patients with neurological signs and symptoms

METHODS—A total of 43 children with neurological signs and symptoms were enrolled in the study. All children were suspected of having meningitis, and lumbar punctures were performed. Human herpesvirus 6 (HHV-6) and HHV-7 DNA was detected in cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) by nested polymerase chain reaction.
RESULTS—Most patients had detectable serum antibody to both HHV6 and 7. HHV6 DNA was detected in PBMC of 15 patients and in CSF cell pellet of seven. Corresponding figures for HHV7 were 28 and 6.2/7, and 5/6 with CSF viral DNA also had it in PBMC, respectively. No viral DNA was detected in CSF supernatants. The seven HHV6 CSF viruses were all variant B.
CONCLUSION—These data suggest that HHV-7 may invade the CNS.

     

Congenital cardiac anomalies with vein of Galen malformations in infants

Published reports and personal experience are reviewed relating to patients under 1 year of age diagnosed with a vein of Galen malformation and congenital heart disease. Including five patients from this institution, a total of 23 patients (12 neonates) with congenital heart disease and a vein of Galen malformation have been reported. Six of these had sinus venosus atrial septal defect and nine had aortic coarctation.

     

Invasion by human herpesvirus 6 and human herpesvirus 7 of the central nervous system in patients with neurological signs and symptoms.

METHODS: A total of 43 children with neurological signs and symptoms were enrolled in the study. All children were suspected of having meningitis, and lumbar punctures were performed. Human herpesvirus 6 (HHV-6) and HHV-7 DNA was detected in cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) by nested polymerase chain reaction. RESULTS: Most patients had detectable serum antibody to both HHV6 and 7. HHV6 DNA was detected in PBMC of 15 patients and in CSF cell pellet of seven. Corresponding figures for HHV7 were 28 and 6.2/7, and 5/6 with CSF viral DNA also had it in PBMC, respectively. No viral DNA was detected in CSF supernatants. The seven HHV6 CSF viruses were all variant B. CONCLUSION: These data suggest that HHV-7 may invade the CNS.     

Detection of congenital cytomegalovirus infection in Chinese newborn infants using polymerase chain reaction

Polymerase chain reaction (PCR) amplification was used to detect cytomegalovirus (CMV) in 1000 urine specimens from Chinese newborns for defining the incidence of congenital CMV infection in the Chinese population. The major immediate-early and the late antigen genes of CMV were amplified and detected by gel electrophoresis. There were 18 congenitally infected infants found when tests were performed with one or both primer pairs. Comparing with tissue culture, PCR of both primer sets provided a sensitivity of 94%, a specificity of 100% and a predictive value of positive result of 100%.     

Randomised controlled trial of cisapride in feed intolerance in preterm infants

AIM—To assess the efficacy of cisapride in reducing the time required to establish enteral feeds in preterm infants.
METHODS—A randomised, double blind, placebo controlled trial was conducted of 34 infants of ⩽ 32 weeks of gestation, assigned to receive either cisapride 0.2 mg/kg/dose four times daily (n=18) or placebo (n=16).
RESULTS—The time taken by the babies to tolerate full enteral feeds was not significantly different between the groups (median 9.5days vs 10 days). There was a significantly lower incidence of large gastric residuals and regurgitation in the treated group compared with the placebo group. The number of episodes of large gastric residuals per infant was also significantly less. No adverse effects were noted.
CONCLUSION—The routine use of cisapride in preterm infants cannot be recommended to decrease the time to establish enteral feeds. Its use may be justified for clincally significant gastric stasis or regurgitation.

     

Antioxidant activity,packed cell transfusions,and outcome in premature infants

AIM—To evaluate the relative importance of biochemical markers of antioxidant status, gestational age, and parameters of neonatal care in the clinical outcome of premature infants.
METHOD—A prospective, observational, longitudinal study of the association between these factors was conducted. Blood was collected from an in situ arterial line within two hours of birth and at intervals thereafter, when blood was drawn for routine clinical purposes. Outcome was assessed as death, or survival with or without bronchopulmonary dysplasia (BPD). One hundred and forty four babies of 22 to 39 weeks of gestation, who required intensive care at the Jessop Hospital for Women, between January 1993 and April 1994, were recruited.
RESULTS—Low gestational age at birth was the most important predictor of mortality and the development of BPD. Having corrected for gestational age, low plasma antioxidant activity at birth was an independent risk factor for mortality. Plasma vitamin C at birth was significantly higher in the babies who died compared with those with a good outcome, but this effect was not sustained after correcting for gestational age. Repeated measures of Analysis of Variance revealed a postnatal increase in antioxidant activity, caeruloplasmin, retinol, cholesterol corrected α tocopherol, and red blood cell superoxide dismutase (SOD) activity. Vitamin C, on the other hand, declined in all groups after birth. Logistic regression analysis revealed that the greater the number of packed cell transfusions received during intensive care, and the higher the concentration of vitamin C on the second day of life, the greater the risk of developing BPD.
CONCLUSIONS—After correcting for the effect of gestational age, low plasma antioxidant activity at birth was an independent risk factor for mortality. Frequent blood cell transfusions over the first week of life are associated with an increased risk of developing BPD. This association may be causal.