Antiviral activity of some Nigerian medicinal plant extracts.

Plants from Northern Nigeria with a history of use in both human and veterinary traditional medicine have been investigated for their antiviral activity and their cytotoxicity determined. Extracts were tested against poliovirus, astrovirus, herpes simplex viruses and parvovirus, using the microtitre plate inhibition tests. Most of the extracts have activity against more than one virus at a dose rate of between 100 and 400 microg/100 microl.

PCR sequencing of the spike genes of geographically and chronologically distinct human coronaviruses 229E.

A reverse transcription nested PCR (RT-PCR) sequencing methodology was developed and used to generate sequence data from the spike genes of three geographically and chronologically distinct human coronaviruses 229E. These three coronaviruses were isolated originally from the USA in the 1960s (human coronavirus 229E strain ATCC VR-74), the UK in the 1990s (human coronavirus 229E LRI 281) and Ghana (human coronavirus 229E A162). Upon translation and alignment with the published spike protein sequence of human coronavirus 229E 'LP' (isolated in the UK in the 1970s), it was found that variation within the translated protein sequences was rather limited. In particular, minimal variation was observed between the translated spike protein sequence of human coronaviruses 229E LP and ATCC VR-74 (1/1012 amino acid differences), whilst most variation was observed between the translated spike protein sequence of human coronaviruses 229E LP and A162 (47/1012 amino acid changes). Further, the translated spike protein sequence of human coronavirus 229E A162 showed three clusters of amino acid changes, situated within the 5' half of the translated spike protein sequence.

The relationship between upper respiratory infections and hospital admissions for asthma: a time-trend analysis.

We have shown that viruses are associated with 80 to 85% of asthma exacerbations in school-age children in the community. We hypothesize that viral infections are also associated with severe attacks of asthma precipitating hospital admissions. To investigate this, we conducted a time-trend analysis, comparing the seasonal patterns of respiratory infections and hospital admissions for asthma in adults and children. During a 1-yr study in the Southampton area of the United Kingdom, 108 school-age children monitored upper and lower respiratory symptoms and took peak expiratory flow rate (PEFR) recordings. From children reporting a symptomatic episode or a decrease in PEFR, samples were taken for detection of viruses and atypical bacteria. A total of 232 respiratory viruses and four atypical bacteria were detected. The half-monthly rates of upper respiratory infection were compared with the half-monthly rates for hospital admissions for asthma (International Classification of Diseases [ICD] code 493) for the same time period for the hospitals serving the areas from which the cohort of schoolchildren was drawn. The relationships of upper respiratory infections and hospital admissions for asthma with school attendance were studied. Strong correlations were found between the seasonal patterns of upper respiratory infections and hospital admissions for asthma (r = 0.72; p < 0.0001). This relationship was stronger for pediatric (r = 0.68; p < 0.0001) than for adult admissions (r = 0.53; p < 0.01). Upper respiratory infections and admissions for asthma were more frequent during periods of school attendance (87% of pediatric and 84% of total admissions), than during school holiday periods (p < 0.001). These relationships remained significant when allowance was made for linear trend and seasonal variation using multiple regression analysis (p < 0.01). Not surprisingly, school attendance, because it is a major factor in respiratory virus transmission, was found to be a major confounding variable in children. This study demonstrates that upper respiratory viral infections are strongly associated in time with hospital admissions for asthma in children and adults. Rhinoviruses were the major pathogen implicated, and the majority of viral infections and asthma admissions occurred during school attendance.

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.

Detection of human papillomavirus types in balanitis xerotica obliterans and other penile conditions.

OBJECTIVES: To determine the prevalence of human papillomavirus (HPV) types 6, 11, 16 and 18 in foreskin biopsies from patients with balanitis xerotica obliterans (BXO) and other penile conditions. MATERIALS AND METHODS: Foreskin biopsy specimens from 24 patients with penile lesions and 5 control patients were analysed by type-specific polymerase chain reaction (PCR). RESULTS: HPV6 or HPV16 were not detected in patients with BXO. HPV6 was detected in 2 controls. CONCLUSIONS: Genital papillomaviruses do not have a strong association with BXO.

Gastrointestinal adenovirus infections in a tertiary referral centre in Saudi Arabia.

To determine the prevalence of adenovirus and its serotypes in diarrhoeal stools in Saudi Arabia, 3,000 stool specimens were collected prospectively from subjects of all ages over a 28-month period. A total of 220 positive isolates were obtained. Fifteen serotypes were found, serotypes 40 and 41 being the most prevalent. Underlying disorders were found in the majority of patients, leukaemia being the most common single underlying condition. This investigation represents the first detailed study of the epidemiology of gastrointestinal adenovirus infections in Saudi Arabia.

Community study of role of viral infections in exacerbations of asthma in 9-11 year old children.

OBJECTIVE: To study the association between upper and lower respiratory viral infections and acute exacerbations of asthma in schoolchildren in the community. DESIGN: Community based 13 month longitudinal study using diary card respiratory symptom and peak expiratory flow monitoring to allow early sampling for viruses. SUBJECTS: 108 Children aged 9-11 years who had reported wheeze or cough, or both, in a questionnaire. SETTING: Southampton and surrounding community. MAIN OUTCOME MEASURES: Upper and lower respiratory viral infections detected by polymerase chain reaction or conventional methods, reported exacerbations of asthma, computer identified episodes of respiratory tract symptoms or peak flow reductions. RESULTS: Viruses were detected in 80% of reported episodes of reduced peak expiratory flow, 80% of reported episodes of wheeze, and in 85% of reported episodes of upper respiratory symptoms, cough, wheeze, and a fall in peak expiratory flow. The median duration of reported falls in peak expiratory flow was 14 days, and the median maximum fall in peak expiratory flow was 81 l/min. The most commonly identified virus type was rhinovirus. CONCLUSIONS: This study supports the hypothesis that upper respiratory viral infections are associated with 80-85% of asthma exacerbations in school age children.

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.

Use of a nested PCR method for the detection of astrovirus serotype 1 in human faecal material.

In this paper we describe a reverse-transcription nested polymerase chain reaction method for detecting human astrovirus serotype 1. It has been evaluated on 56 UK diarrhoeal stool specimens and six non-UK specimens. The method has greater sensitivity than electron microscopy and may be a useful test in areas such as the UK where this serotype predominates.

Comparison of paediatric viral gastroenteritis at large medical centres in Saudi Arabia and the United Kingdom.

A comparison of the prevalence of viral diarrhoeas in children was made between the United Kingdom and Saudi Arabia over a three-year period. Laboratory data from Saudi Arabia were compared with those of a large medical centre in the UK. The prevalence ratios of virus-associated diarrhoea as a fraction of all diarrhoeal cases over three years were found to be 23% in the UK and 14% in Saudi Arabia. The relative proportion due to rotavirus and adenovirus was higher in the UK than in Saudi Arabia, but small round viruses were comparable at the two centres.

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.

Antiparasitic activity of Annona muricata and Annona cherimolia seeds.

Methanolic extracts of Annona muricata and A. cherimolia (Annonaceae) seeds were tested for antiparasitic activity against E. histolytica, N. brasiliensis, M. dessetae and A. salina. The acetogenins isolated from these extracts are found to be responsible for the important activity on infective larvae of Molinema desetae.

[Isolation and synthesis of espintanol, a new antiparasitic monoterpene]. / Isolement et synthese de l'espintanol, nouveau monoterpene antiparasitaire.

The in vitro leishmanicidal and trypanocidal activities of a petroleum ether extract of Oxandra espintana have been investigated. Four aromatic monoterpenes were isolated, of which two are novel: espintanol [3a], responsible for the antiparasite activity, and O-methylespintanol [4]. Espintanol was tested in vitro on 20 strains of Trypanosoma cruzi and 12 strains of Leishmania spp. Its structure was determined by spectroscopic methods and confirmed by its preparation starting from carvacrol.