Investigation into a school enterovirus outbreak using PCR detection and serotype identification based on the 5' non-coding region.

A summer camp was followed by an outbreak of illness involving around 90 children. Investigations included individual questionnaires, inspection of the camp facilities, and laboratory analysis of water and clinical samples. Contamination of drinking and swimming water was demonstrated. An enterovirus was detected by polymerase chain reaction (PCR) and/or culture in 4/4 cerebrospinal fluid samples, 9/15 (60%) stool samples from symptomatic children and 2/9 (22%) stool samples from asymptomatic children. The virus was identified as an echovirus 3 by sequencing and phylogenetic analysis of a short 5' non-coding region (NCR) PCR product. Viruses from the outbreak clustered closely and an echovirus 3 from a temporally associated non-outbreak case could be readily distinguished. Despite the lack of a standardized approach, direct molecular detection and identification of enteroviruses is an efficient epidemiological tool. Here the 5'-NCR was successfully used for both detection and 'serotyping', and the close genetic relatedness of isolates was proven.

Genotyping of hepatitis C virus in South Africa.

The six major hepatitis C virus genotypes were investigated by using samples from 79 seropositive and PCR-positive blood donors from three different regions of South Africa as well as 9 patients with chronic renal failure, 19 with liver disease, and 23 with hemophilia. PCR products of the genome were typed by restriction fragment length polymorphic analysis by RsaI-HaeIII and MvaI-HinfI double digestion. Type 5 occurred in 40% of this population group; type 1 occurred in 33%; and types 2, 3, and 4 were found in 13.8, 7.7, and 2.3%, respectively.

DNA single strand conformation polymorphism identifies five defined strains of hepatitis B virus (HBV) during an outbreak of HBV infection in an oncology unit.

An outbreak of hepatitis B virus (HBV) infection in a children's oncology unit was identified in which 61 children were shown to have been infected, 59 of them asymptomatically. In order to establish whether intra-unit cross infection had occurred, we used the single strand conformational polymorphism (SSCP) technique to analyse viral isolates from 57 of the infected children and 40 unrelated controls. HBV-specific primers were designed to amplify a 189 bp fragment of DNA encompassing part of the hypervariable pre-S1 region of the HBV genome. Denatured PCR products were compared after electrophoresis through polyacrylamide gels and staining with silver. By SSCP analysis, the unrelated infections each yielded a unique electrophoretic banding pattern, indicative of a variety of distinct virus strains. In contrast, most of the oncology patients had been infected with one of only five different strains. Three major groups comprising 19, 16, and 9 patients, respectively, and two minor groups of 5 and 3 patients were identified. Results indicate the occurrence of multiple episodes of cross infection, and demonstrate the sensitivity and value of SSCP as a technique to establish common sources of infection.

Two new genome types of adenovirus 7c.

Adenovirus type 7 is the type most frequently associated with serious disease. Eighteen different genome types of adenovirus type 7 had been reported up to October 1986. The genome type Ad7c, based on the restriction enzyme profiles of SmaI and BamHI, has been reported from Europe prior to 1969 and more recently from South Africa. Here, we report two new genome types of adenovirus 7 c that have not previously been identified and that have been isolated in South Africa between 1975 and 1986 from children with postmeasles pneumonia. The two new genome types differ from the prototype Ad7c virus in having two (Ad7c1) or one (Ad7c2) extra cleavage sites for the restriction endonuclease EcoRI. These sites have been located at 3.68kb and 5.32kb from the left terminus of the genome map published for the prototype Ad7c strain. A strain resembling the prototype Ad7c was also isolated in 1986 from a case of post measles pneumonia.

Safety and efficacy of interferon alpha-2b following prednisone withdrawal in the treatment of chronic viral hepatitis B. A case-controlled, randomised study.

The therapeutic effects of interferon alpha-2b (Intron A; Scherag) in patients with chronic active hepatitis caused by hepatitis B virus (HBV) were assessed in a randomised, case-controlled clinical trial conducted between January 1988 and June 1990. Treatment involved a short course of prednisone followed by interferon alpha-2b, initially 10 million U by subcutaneous injection, 3 times a week for 16 weeks. All patients were symptomatic, were known to have had hepatitis B surface antigen and hepatitis B e antigen (HBeAg) in their blood for at least 6 months, and had elevated serum aminotransferase activities with histological evidence of chronic active hepatitis. Patients with carcinoma, renal or haematological abnormalities or decompensated cirrhosis were excluded. In 6 of 10 patients randomised to receive interferon and 1 of 10 controls, HBeAg and HBV DNA were cleared from the blood during the 12-month study period (P < 0.05). An indeterminate response with clearance of HBV DNA but persistence of HBeAg was noted in 1 patient receiving interferon. Serum aminotransferase levels decreased only in those patients who had responded to treatment, but this did not reach statistical significance for the group as a whole. Histological studies, where available, showed decreased hepatic periportal necrosis in patients who underwent treatment. Two patients relapsed to HBeAg-positive status 2 months after their initial seroconversion; 1 became clear again during a repeat course of interferon. Side-effects of treatment were common and included fever, malaise, myalgias and myelosuppression. One patient developed hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Porphyria cutanea tarda: the etiological importance of mutations in the HFE gene and viral infection is population-dependent.

A number of factors, including increased iron stores and alcohol consumption, are known to be associated with the development of porphyria cutanea tarda (PCT) in susceptible individuals. Recent reports have described a significant association between inheritance of the C282Y and H63D mutations in the HFE gene, associated with genetic hemochromatosis (GH) and PCT. A strong association between hepatitis C virus infection and PCT has also been demonstrated, while case reports record a link between human immunodeficiency virus (HIV) and PCT. We have investigated the frequency of these factors in a racially-mixed population of patients with PCT in Cape Town, South Africa. 57 patients with PCT drawn from three ethnic groups were screened for the presence of the C282Y and H63D mutations linked to GH, and the prevalences were compared with corresponding healthy control populations. The seroprevalence of markers for HCV, hepatitis B (HBV) and HIV infection were examined in 28 of these. In the control populations, we found that both the C282Y and H63D mutations are highly prevalent in South Africans of European origin. In a population of mixed or Asian origin, the C282Y mutation is very rare whereas the H63D mutation is common. Neither mutation was encountered in any African subject. Both mutations are associated with PCT, but the association is dependent on the ethnic origins of the population to which the patient belongs. In contrast to other studies, HCV infection is numerically unimportant in PCT in our patients. HIV infection is increasingly encountered in our patients with PCT, but the strength of the association cannot be determined in view of the high background prevalence of HIV infection in some sectors of the South African population. The contribution of specific risk factors may be heavily dependent on the population from which patients are drawn, and care should be taken in extrapolating from observations in one racial or geographic population to any other.

Hepatitis E in South Africa: evidence for sporadic spread and increased seroprevalence in rural areas.

Hepatitis E virus (HEV) is a major cause of non-A, non-B hepatitis in developing countries. Factors influencing sporadic spread of hepatitis E are unclear. We examined anti-HEV seroprevalence and demographic data from 407 urban and 360 rural black South African adults living in formal housing, squatter camps, or mud huts. Anti-HEV sero-prevalence ranged from 5.8% to 19.1% (mean 10.7%) in the different regions. Mean urban and rural rates were 6.6% and 15.3%, respectively (P = 0.0001). Rural mud hut dwellers, using unchlorinated river water, were at greater risk (17.4%) than rural villagers (5.3%; P = 0.008). A linear relation was found between seroprevalence and age, suggesting sporadic spread. The high prevalence in mud hut dwellers suggests that contaminated water plays a major role in HEV spread in South Africa. Routine chlorination or boiling of river drinking water before consumption may reduce HEV infection.

Hepatitis C virus infection rate in volunteer blood donors from the Western Cape--comparison of screening tests and PCR.

INTRODUCTION: Hepatitis C virus (HCV) antibody seroprevalence studies overestimate the true infection rate. No data exist on the incidence of HCV or its clinical features in blood donors of sub-Saharan Africa. AIMS: To establish the true incidence of HCV infection in volunteer blood donors in the Western Cape, and compare risk factors and clinical and biochemical features of viraemic and non-viraemic subjects. METHODS: All donors attending the Western Province Blood Transfusion Service between December 1992 and August 1994 were screened prospectively for anti-HCV using the Abbott second-generation assay. Positive donors were evaluated clinically and biochemically. Their sera were examined for HCV-RNA by the polymerase chain reaction (PCR). RESULTS: Of 66314 donors screened, 275 (0.41%) were anti-HCV-positive. Of these 13.6% were PCR-positive (0.056% of all donors). PCR-positive patients had more risk factors for HCV acquisition (P < 0.01), symptoms of hepatitis (P = 0.02) and clinical signs of liver disease (P = 0.05) and higher alanine (P < 0.0001) and aspartate aminotransferase levels (P < 0.0001) than PCR-negative donors. However, clinical and biochemical features did not discriminate adequately between PCR-positive and negative donors. Liver biopsies performed in 9 of 13 PCR-positive cases showed mild inflammation, but no cirrhosis.