Steven Myint

Human Coronavirus Infections

The first report of a human coronavirus was in 1965 when Tyrrell and Bynoe (1965) isolated a virus from the nasal washings of a male child. The child had typical symptoms and signs of a common cold and the washing was found to be able to induce common colds in volunteers challenged intranasally. The virus, termed B814 (after the number of the nasal washing), could be cultivated in human embryo tracheal organ tissue but not in cell lines used at that time for growing other known etiologic agents of the common cold. At the same time, Hamre and Procknow (1966) were characterizing five “new” agents isolated from the respiratory tract of medical students with colds. One of these agents, strain 229E, was adapted to grow in WI-38 cells. Subsequently, Almeida and Tyrrell (1967) showed that these isolates were morphologically identical to the viruses of avian bronchitis and mouse hepatitis. Mcintosh and colleagues (1967a), working at the National Institutes of Health in Bethesda, then isolated six morphologically related viruses that could not be adapted to cell monolayer culture but would grow in organ cultures. Two of these isolates, OC (for organ culture) 38 and 43 were then adapted to grow in suckling mice brain. The term “Coronavirus,” which described the characteristic morphology of these agents, was accepted in 1968 (Tyrrell et al., 1968a).

Viral contamination of environmental surfaces on a general paediatric ward and playroom in a major referral centre in Riyadh

In order to determine the incidence of viral contamination of environmental surfaces in a hospital in Saudi Arabia. A 6-month prospective study was carried out on a general paediatric ward in which both enteric and respiratory viruses were screened. Weekly samples were taken between August 1993–February 1994. A total of 155 samples were taken in which 11 (7%) tested positive for rotavirus. No other viruses were detected. Internal and external temperatures were monitored and an increase in rotavirus incidence was noted with decrease in temperature. Rotavirus was detected on surfaces involving human activity (toilet handles, televisions, toys and vital signs chart). One patient had rotavirus on his hands but no staff were found to carry rotavirus. Further contamination of environmental surfaces (9%) was detected during an increased incidence of rotavirus infection. A proper programme of disinfection and handwashing is essential in order to eliminate this mode of transmission.

Experimental common cold increases mucosal output of eotaxin in atopic individuals

Background: In view of recent observations demonstrating that rhinovirus infections are associated with increased local activity of eosinophils, we hypothesized that eotaxin, a selective eosinophil chemoattractant, may be involved in eosinophil recruitment/activation in common cold infections.

AETIOLOGY OF GASTROENTERITIS AT A MAJOR REFERRAL CENTRE IN SAUDI ARABIA

To determine the causes of gastroenteritis at a major referral centre in Saudi Arabia, retrospective study was carried out on 58,110 fresh stools from 42,035 patients. Examination of stool specimens for pathogens was based on the clinical judgement of the physician responsible, so that all specimens were not tested for the presence of all pathogen groups. Bacterial enteropathogens were found in 7.7% of patients; Salmonella species (51.7%) were found to be the most frequent pathogens followed by Campylobacter jejuni (28%) and Shigella species (14.9%). Protozoan or metazoan parasites were detected in 27.8% of patients examined, the most common being Giardia lamblia and Hymenolepsis nana. Of the patients tested for viruses in stool, 14.1% had rotavirus, 5.3% adenovirus, 1.2% small round viruses and 0.3% coronavirus. Clostridium difficile toxin was also found in 9.5% of patients examined.

Recent advances in the rapid diagnosis of respiratory tract infection.

Abstract Molecular techniques have enabled major advances in the speed and sensitivity of the laboratory diagnosis of respiratory infections. Although the polymerase chain reaction is the most commonly used, there are several other methods available, which have applicability across the range of microbial pathogens.

The incidence and detection of HPV in the upper aerodigestive tract using brush and biopsy techniques.

The association between human papillomavirus (HPV) and squamous carcinoma is well established. In the polymerase chain reaction (PCR) we have an effective technique for detecting small quantities of viral DNA, but the assay requires tissue taken at endoscopy to reveal the presence or absence of HPV. Brushings have been used effectively elsewhere in the body to obtain cytological material. This study set out to ascertain if sufficient viral DNA could be obtained, using a laryngeal brushing and the PCR, to detect the presence or absence of HPV. Six patients with squamous carcinoma of the larynx and seven controls who were having laryngoscopy for other reasons underwent laryngeal biopsy. In addition, in the patients with carcinoma, biopsies were taken at the tumour margins and brushings from both sites. The samples were tested for the presence of HPV types 6, 11, 16, 18 and 31 by means of the PCR. The distribution of HPV types was as expected in the biopsy specimens, but only one brushing detected any HPV type at all. We conclude that laryngeal brushing is an inadequate technique for assessing the presence of HPV in the larynx.

Diagnosis of astrovirus by reverse transcriptase PCR in stools from patients in the UK and Saudi Arabia.

BACKGROUND Astroviruses are becoming increasingly recognised as a cause of diarrhoea in children, and to a lesser extent, adults. Electron microscopy is the recognised standard for diagnosis but is not available in many centres. OBJECTIVES This study set out to evaluate a RT-PCR method for the diagnosis of astrovirus in faecal specimens. STUDY DESIGN 130 diarrhoeal stools were collected prospectively both from Saudi Arabia and Leicester, UK. The patients from each centre were age-matched. Twenty control isolates from food service staff without clinical illness were also collected. Both electron microscopy (EM) and RT-PCR (for astrovirus serotype 1) were used to diagnose astrovirus infection. RESULTS Of 23 PCR-positive specimens, only 17 were detected by EM. The prevalence of astrovirus serotype 1 was determined by PCR as 1.5% in Saudi Arabia and 4.6% in the UK. CONCLUSION RT-PCR is a more sensitive alternative to EM for astrovirus serotype 1.

Common Colds, Asthma and Indoor Air Quality

Most common colds are caused by rhinoviruses and coronaviruses. These viruses are now thought to provoke the majority of asthmatic attacks in children. This article summarises the role that these viruses play in inducing asthma and discusses the interaction between air pollution and virus-induced asthma.

Preventing severe infection after splenectomy: Authors' reply

EDITOR—Sciberras asks an important question, as many asplenic patients had surgery at a time when the risks of postoperative infection were even less appreciated than at present. Although most infections do occur in the first two years after surgery, most studies will …

The presence of Epstein-Barr virus in multiple organs in a fatal case of virus-associated haemophagocytic syndrome

We describe a case report of a 21-year-old male with fatal Epstein-Barr virus-associated haemophagocytic syndrome. Virus is detected in multiple organs by polymerase chain reaction and in the tissue-specific cells of those organs by in situ hybridisation. It is suggested that organ failure may be a direct response to infection.