Frankie Wai Tsoi Cheng

HUMAN METAPNEUMOVIRUS DETECTION IN PATIENTS WITH SEVERE ACUTE RESPIRATORY SYNDROME

We used a combination approach of conventional virus isolation and molecular techniques to detect human metapneumovirus (HMPV) in patients with severe acute respiratory syndrome (SARS). Of the 48 study patients, 25 (52.1%) were infected with HMPV; 6 of these 25 patients were also infected with coronavirus, and another 5 patients (10.4%) were infected with coronavirus alone. Using this combination approach, we found that human laryngeal carcinoma (HEp-2) cells were superior to rhesus monkey kidney (LLC-MK2) cells commonly used in previous studies for isolation of HMPV. These widely available HEp-2 cells should be included in conjunction with a molecular method for cell culture followup to detect HMPV, particularly in patients with SARS.

Immunofluorescence Assay for Serologic Diagnosis of SARS

We evaluated a virus-infected cell-based indirect immunofluorescence assay for detecting anti–severe acute respiratory syndrome-associated coronavirus (SARS-CoV) immunoglobulin (Ig) G antibody. All confirmed SARS cases demonstrated seroconversion or fourfold rise in IgG antibody titer; no control was positive. Sensitivity and specificity of this assay were both 100%. Immunofluorescence assay can ascertain the status of SARS-CoV infection.

Infection control for SARS in a tertiary paediatric centre in Hong Kong

Abstract Severe acute respiratory syndrome (SARS) is an emerging infectious disease. After the appearance of an index patient in Hong Kong in February 2003, SARS outbreaks occurred rapidly in hospitals and spread to the community. The aim of this retrospective study is to evaluate the effectiveness of a triage policy and risk-stratified infection control measures in preventing nosocomial SARS infection among paediatric healthcare workers (HCWs) at the Prince of Wales Hospital, a general hospital to which children with SARS are referred in Hong Kong. The acute paediatric wards were stratified into three areas: (1) ultra high-risk area, (2) high-risk area and (3) moderate-risk area according to different risk levels of nosocomial SARS transmission. The implementation of different levels of infection control precautions was guided by this risk stratification strategy. Between 13 March and 23 June, 38 patients with probable and suspected SARS, 90 patients with non-SARS pneumonia, and 510 patients without pneumonia were admitted into our unit. All probable SARS cases were isolated in negative-pressure rooms. Twenty-six HCWs worked in the ultra high-risk area caring for SARS patients and 88 HCWs managed non-SARS patients in other ward areas. None of the HCWs developed clinical features suggestive of SARS. In addition, there was no nosocomial spread of SARS-associated coronavirus to other patients or visitors during this period. In conclusion, stringent infection control precautions, appropriate triage and prompt isolation of potential SARS patients may have contributed to a lack of nosocomial spread and HCW acquisition of SARS in our unit.

Pulmonary metastases in children with osteosarcoma: characteristics and impact on patient survival

BackgroundApproximately 15–20% of patients with osteosarcoma present with detectable metastatic disease and the majority of whom (85%) have pulmonary lesions as the sole site of metastasis. Previous studies have shown that the overall survival rate among patients with localized osteosarcoma without metastatic disease is approximately 60–70% whereas survival rate reduces to 10–30% in patients with metastatic disease.ObjectiveTo determine the incidence and characteristic features of pulmonary metastases in a group of osteosarcoma patients and correlate the findings with the prognostic outcome/survival.Materials and methodsSeventy-seven cases of histologically confirmed osteosarcoma were reviewed (47 male, 30 female, mean age 10.9). The site and size of the primary tumour and degrees of chemonecrosis were recorded. Lung metastases were analyzed according to their size, number, distribution and interval from diagnosis. The Kaplan-Meier method was used to analyze the survival probability curve. Significant differences (P < 0.05) were evaluated with the log-rank test for univariate analyses.ResultsSeventeen patients had synchronous and 11 had metachronous lung metastases. Sixteen (57%) underwent pulmonary metastasectomy. Nine of sixteen (56%) patients with metastasectomy and 10/12 (83%) patients without metastasectomy died. Poor chemonecrosis was associated with a worse outcome. Number, distribution and timing of lung metastases, but not the size of lung metastases, were of prognostic value for survival.ConclusionRadiological detection of lung metastases is clinically important as it indicates a worse prognosis.

Probable Intrafamilial Transmission of Coxsackievirus B3 With Vertical Transmission, Severe Early-Onset Neonatal Hepatitis, and Prolonged Viral RNA Shedding

Here we report a familial cluster of 3 cases of coxsackievirus B3 infection: a recent history of illness in a womans 3-year-old son with a coxsackievirus B3–positive stool culture indicated that he probably infected his mother at home during her last week of pregnancy. Consequently, she delivered an infected neonate who developed severe hepatitis, disseminated intravascular coagulation, and bilateral intracranial hemorrhage. The neonate remained well for the first 2 days of life. On the third day, he developed fever (39°C) and poor peripheral circulation. On the fourth day, he developed petechiae and bruises over his chest wall and extremities, and prolonged bleeding was observed over venipuncture sites. Investigations revealed severe thrombocytopenia (platelets: 41 × 109/L) and a markedly deranged coagulation profile (prothrombin time: 19 seconds [reference: <10 seconds]; activated partial thromboplastin time: >120 seconds [reference: 24.2–37.0 seconds], serum D-dimers: 6722 ng/mL [reference: <500 ng/mL]), suggestive of disseminated intravascular coagulopathy. Clinical examination revealed yellow sclera, hepatomegaly (5 cm), and splenomegaly (2 cm), consistent with hepatitis. Serial chest radiographs showed bilateral pleural effusions, and an ultrasound of the abdomen demonstrated ascites. An echocardiogram showed normal cardiac structure and good contractility of both ventricles. However, a cranial ultrasound revealed bilateral grade 2 intraventricular hemorrhages. Serum C-reactive protein increased to 33.9 mg/L. Liver-function tests were also markedly deranged at this time, with maximum values for serum alanine transferase, bilirubin, alkaline phosphatase, and ammonia concentration of 1354 IU/L, 258 μmol/L, 189 IU/L, and 147 μmol/L, respectively. Serum glucose levels were normal. Over the next 3 days, his fever subsided, and his liver function and clotting profile normalized by day 13 after onset of illness. A stool sample from the older brother, collected 14 days after his onset of illness at home, was positive for coxsackievirus B3 by both virus culture and enterovirus reverse-transcription polymerase chain reaction. He had neutralizing coxsackievirus B3 antibody titers of 1:2560 and 1:1280 on days 14 and 28 after his onset of illness, respectively. No virus was cultured from the mothers stool sample, collected 5 days after her onset of illness, but the enterovirus polymerase chain reaction was positive and maternal sera neutralized the coxsackievirus B3 isolated from the neonate. The maternal sera also showed a more than fourfold rise in antibody titer from 1:80 to 1:640 on days 5 and 16 after her onset of illness, respectively. Neonatal antibody titers also showed a more than fourfold rise from <1:80 to 1:2560 on days 1 and 21 after his onset of illness, respectively. This demonstrates that both the mother and the neonate had had recent coxsackievirus B3 infections. Serially collected neonatal throat swab and stool samples were culture negative for enterovirus by 4 and 8 days after his onset of illness, respectively. However, enterovirus RNA remained detectable by reverse-transcription polymerase chain reaction in these samples for considerably longer, only becoming undetectable by 16, 23, and 41 days after his onset of illness. We show that even mild household infections may have potentially serious consequences for pregnant women and their infants.

A pilot randomized study to assess immunogenicity, reactogenicity, safety and tolerability of two human papillomavirus vaccines administered intramuscularly and intradermally to females aged 18-26 years.

Intradermal administration of human papillomavirus (HPV) vaccines could be dose-sparing and cost-saving. This pilot randomized study assessed Cervarix(®) and Gardasil(®) administered either intramuscularly or intradermally, in different doses (full-dose or reduced to 20%) by different methods (needle and syringe or PharmaJet needle-free jet injection device). Following an initial reactogenicity study of 10 male subjects, sexually naïve women aged 18-26 years were randomized to the eight study groups to receive vaccine at 0, 2 and 6 months. 42 female subjects were enrolled and complete data were available for 40 subjects. Intradermal administration of either vaccine raised no safety concerns but was more reactogenic than intramuscular administration, although still tolerable. All subjects demonstrated a seroconversion (titre≥1:320) by Day 95. Further evaluation of intradermal HPV vaccination and its potential for cost reduction in resource poor settings is warranted.

Atypical location of germinoma in basal ganglia in adolescents: radiological features and treatment outcomes

The objective of this work is to describe the imaging findings, clinical profile and treatment response in four Chinese adolescent patients presenting with ectopic germinoma arising from basal ganglia. The clinical presentation, treatment regimens and the imaging findings at presentation and after treatment were described upon retrospective review of four Chinese adolescent patients. CT of the brain showed mixed solid cystic mass lesions in three patients. In one patient, only ill-defined hyperdensity was noted in the affected basal ganglia. Correlative MRI brain studies showed similar findings of large solid cystic masses in three patients, whereas the fourth patient showed small hyperintensities on T2 weighted and fluid-attenuated inversion-recovery sequences. All lesions were confirmed to be germinomas on biopsy. Chemotherapy followed by radiotherapy was given to three patients. There was a dramatic response, with complete resolution of tumour bulk in two patients and >80% reduction in tumour bulk in one patient. Debulking surgery was performed in one subject who had received cranial radiotherapy; the last follow-up MRI showed no evidence of residual disease.

Infection control for SARS in a tertiary neonatal centre.

The Severe Acute Respiratory Syndrome (SARS) is a newly discovered infectious disease caused by a novel coronavirus, which can readily spread in the healthcare setting. A recent community outbreak in Hong Kong infected a significant number of pregnant women who subsequently required emergency caesarean section for deteriorating maternal condition and respiratory failure. As no neonatal clinician has any experience in looking after these high risk infants, stringent infection control measures for prevention of cross infection between patients and staff are important to safeguard the wellbeing of the work force and to avoid nosocomial spread of SARS within the neonatal unit. This article describes the infection control and patient triage policy of the neonatal unit at the Prince of Wales Hospital, Hong Kong. We hope this information is useful in helping other units to formulate their own infection control plans according to their own unit configuration and clinical needs.

HHV‐6 encephalitis in pediatric unrelated umbilical cord transplantation: A role for ganciclovir prophylaxis?

Cheng FWT, Lee V, Leung WK, Chan PKS, Leung TF, Shing MK, Li CK. HHV‐6 encephalitis in pediatric unrelated umbilical cord transplantation: A role for ganciclovir prophylaxis? 
Pediatr Transplantation 2010: 14:483–487.

Rapid control of norovirus gastroenteritis outbreak in an acute paediatric ward

AIM To provide a practical action plan for effective infection control of norovirus outbreak in acute paediatric wards. METHODS We report the infection control measures that were implemented to terminate and to prevent nosocomial spread of norovirus gastroenteritis in an open-designed paediatric ward. RESULTS Nine children, one visitor, and one medical student were affected in a norovirus gastroenteritis outbreak in an acute paediatric ward. Vomiting was the main presenting symptom. The outbreak was rapidly terminated three days after implementation of stringent infection control measures and there was no second wave of attack. These measures included strict contact precautions, prompt isolation and cohorting of symptomatic patients, vigorous environmental cleansing with concentrated disinfectant (hypochlorite solution 1000 ppm), meticulous handling of waste products, and efficient contact tracing of exposed patients, family members, and medical students. CONCLUSION Prompt implementation of stringent infection control measures and contact tracing can rapidly terminate the norovirus outbreak and prevent a second wave of infection. Children with unexplained vomiting and those with contact history of gastroenteritis should be properly triaged, isolated, and investigated for possible infective causes, including norovirus-induced gastroenteritis.