Seroepidemiological study of Helicobacter pylori infection in asymptomatic people in South Korea.

BACKGROUND: Helicobacter pylori infection occurs throughout the world and causes gastroduodenal diseases in all age groups. The prevalence of H. pylori infection varies between countries and races. The aim of this study was to evaluate the seroprevalence of H. pylori infection in asymptomatic healthy people in South Korea. METHODS: From March 1998 to October 1998, 5732 asymptomatic subjects who responded to the self-assessment questionnaires from 54 hospitals in South Korea were enrolled in this study. The serum levels of antibodies for H. pylori immunoglobulinG were measured by using an ELISA test. RESULTS: The overall seroprevalence of H. pylori infection was 46.6% and there was no statistical difference between males (47.2%) and females (45.9%). In adults, a significant difference was observed between genders. According to the geographic areas, the high prevalent provinces were Kangwon (53.4%), Cheju (52.9%) and Cholla province (50.6%); Seoul (41.9%) was the lowest prevalent area. The seroprevalence increased with age and was highest when patients were aged in their 40s (78.5%). The characteristic feature of our study was that the infection rate was steeply increased in three age groups (10-12 year olds, 16-19 year olds and those aged in their 20s). In Seoul, there was no difference in the prevalence rate among the districts studied. CONCLUSIONS: This nation-wide seroprevalence of H. pylori infection in South Korea was 46.6%, which showed the transition from a developing country to a developed country. More studies on the epidemiological factors and the route of transmission of H. pylori infection should be warranted.

Overview of rotavirus infections in Korea.

Rotavirus is the most common cause of acute watery diarrhea in young Korean children. Rotavirus vaccine will soon be available, and information is urgently required about the serotype distribution of recent epidemics and clinical characteristics of rotavirus infection in Korean children before the implementation of a vaccination program against rotavirus. We reviewed published studies of the past 20 years, carried out on Korean children with rotavirus gastroenteritis. Rotavirus was estimated to be responsible for 46% of 4668 hospitalized Korean children with acute gastroenteritis. Rotavirus gastroenteritis was most prevalent among children aged 6-24 months, which accounted for 84% of all cases. Asymptomatic rotavirus infection was common. Rotavirus was one of the most commonly identified enteric pathogens in nosocomial diarrhea. Vomiting, respiratory symptoms and fever were prominent symptoms in rotavirus gastroenteritis. Transient elevation of liver enzymes, pulmonic infiltration and rarely afebrile convulsion were also observed. The epidemic peak, which occurred in November of the last 15 years, has been moving toward late winter and early spring in recent years. No apparent cause has been found to explain this alteration of peak seasonality. All serotyping studies in Korea for the past 10 years until 1997 revealed that G1 was most prevalent (45-81%). Interestingly, the predominant G serotype of the recent outbreaks in 1998 and 1999 was not G1 but G4. Approximately 95% of rotavirus isolates in recent outbreaks belonged to serotype G1, 2, 3 or 4.

Relationships within and between genotypes of hepatitis B virus at points across the genome: footprints of recombination in certain isolates.

Hepatitis B virus (HBV) was partitioned into type, subtype and isolate categories and the average evolutionary distances within and between categories was plotted at each of 54 points along the genome. The graphs showed alternating variable and conserved domains within and between HBV subtypes and revealed that some specimens assigned to different groups are more similar across several contiguous intervals than specimens belonging to the same group. Isolates were screened individually to determine their conformation to type and mosaic structure was identified in 14/65 specimens. Two entire clades (six specimens) of genotype B had a B/C sequence switch in the core gene region, whereas six genotype D specimens showed D/A switching in one or more regions of the genome. Genotype E was not separate from genotype D in the X and C subgenomic regions. The nature and distribution of polymorphic sites in mosaic regions was mapped at both the nucleotide and protein levels and the position of the variant fragments was related to mutational hot spots and linear epitopes of HBV. Mosaic structure was demonstrated statistically in 11 isolates using bootstrap resampling and recombination, rather than random change, appeared to be the mechanism responsible. The sequence between and including the two DR regions was represented in all putative recombinants. The distribution of genetic distances over subgenomic regions showed that substitution rates are not constant among the lineages of HBV in the preS regions. Genotype F is the most diverse group. Only genotypes A, C and F partition consistently into subtypes.

A unique segment of the hepatitis B virus group A genotype identified in isolates from South Africa.

The preS2/S genes of hepatitis B virus isolated from 29 acutely or chronically infected individuals in the Gauteng province of South Africa were sequenced. Phylogenetic analysis of these sequences in comparison with global isolates from the GenBank database showed that 24 sequences clustered with genotypic group A, three with genotypic group D and one each with genotypic groups B and C. Group A isolates had greater identity with groups D (variation of 6.6%) and E (6.8%) than with the Eastern groups B (7.4%) and C (8.1%) and were most different from group F (11.0%). Of the South African group A specimens, 59.1% clustered with two global sequences to form a discrete segment which we have called subgroup A. The amino acid differences that set these isolates apart from the rest of group A tended to cluster in the preS2 region (amino acids 7, 10, 32, 35, 47, 48, 53 and 54), with a few changes occurring in the major surface antigen (amino acid sites 207 and 209). Analysis of isolates showed that there was a 9-fold higher prevalence of the ay determinant in South Africa than previously reported.

Acute HIV seroconversion illness presenting as African viral haemorrhagic fever.

BACKGROUND: Both human immunodeficiency virus type 1 (HIV-1) and African viral haemorrhagic fever (VHF) viruses cause similar symptoms in acutely infected individuals and must be included in the differential diagnosis in areas where HIV-1 and VHF viruses both occur. OBJECTIVES: To determine the cause of an acute illness in a patient at risk of exposure to both HIV-1 and African VHF viruses. RESULTS: Serological examination revealed the presence of high levels of the p24 core antigen of HIV-1 in the absence of antibodies to HIV-1 in a specimen collected during the acute stage of the infection. On follow-up, the antigen enzyme-linked immunosorbent assay (ELISA) became negative while the antibody ELISA and confirmatory Western blot for HIV-1 became positive. CONCLUSIONS: Acute HIV seroconversion illness may have protean manifestations and, in the more severe forms, may cause diagnostic dilemmas, particularly in regions where African VHFs occur.

The value of Helicobacter pylori IgG antibody in estimating the severity of gastritis in children.

A serologic test for antibodies is useful for diagnosis of Helicobacter pylori(H.pylori) infection in children. We evaluated the reliability of H.pylori IgG antibody titer in grading the severity of infection in children. We surveyed the sero-prevalence of H.pylori infection in 300 healthy school children (13 to 15 years old). Thirty-four percent(102 of 300 children) were sero-positive for H.pylori. Of the 102 sero-positive children, 70 underwent gastroscopic examination. Ninety percent of sero-positive children(63 of 70 children) were proven to be H.pylori infected. All children with H.pylori infection had histologically proven gastritis, and its severity did not correlate with the IgG antibody titer. Although a serologic test is useful to identify H.pylori infection in children, it can not predict the severity of H.pylori associated gastritis.

The role of serology in the diagnosis of Helicobacter pylori infection in children.

The aim of this study was to evaluate the diagnostic accuracy of serologic tests and to verify whether specific IgG antibody can be used in the diagnosis of Helicobacter pylori infection in children without endoscopy. Serologic and endoscopic examinations were performed in 310 children (1 month-15 years) with gastrointestinal symptoms. Serologic outcomes were compared with the results of rapid urease test, histologic examination, and culture. The prevalence of H. pylori infection was 21.0% and the seropositivity of H. pylori was 24.2% in these symptomatic children. Serologic examination for diagnosis of H. pylori showed a sensitivity of 94.9% and a specificity of 92.4%, diagnostic reliability equal to the rapid urease test and histologic examination in children. The serum IgG test is a useful tool for the diagnosis of H. pylori infection, especially in children.

CD4+ lymphocyte count in African patients co-infected with HIV and tuberculosis.

The objectives of this study were (a) to compare the CD4+ lymphocyte profiles over time of two groups of patients hospitalized for tuberculosis (TB) treatment [a group of patients with TB only (TB group) and a group dually infected by HIV and TB (HIV/TB group)] and (b) to assess the usefulness of the total lymphocyte count (TLC) as a surrogate of the CD4+ lymphocyte count in the HIV/TB group. A total of 345 patients were enrolled in the study of whom 104 (29.8%) were HIV seropositive (HIV/TB). On admission, the CD4+ lymphocyte counts of the HIV/TB cohort were significantly lower than the TB group with medians of 230 (interquartile range, 90-475) and 630 (500-865), respectively (p < 0.0001). The CD4+ lymphocyte count increased significantly in both cohorts on routine TB treatment. A TLC of 1,300-1,500 cells/mm3 was found to be predictive of a CD4+ lymphocyte count of < or = 200 cells/mm3 both on admission and after 1 month of TB therapy. We conclude from this study that the positive influence of TB therapy on the CD4+ lymphocyte count strongly suggests an additional avenue of influence on the course of HIV infection, whereas the usefulness of the TLC as a surrogate estimation of CD4+ lymphocyte count in HIV/TB patients has important implications for the developing world.

The Johannesburg cardiac rehabilitation programme.

Cardiac rehabilitation has become a generally accepted mode of treatment for patients suffering from coronary artery disease. The Johannesburg cardiac rehabilitation programme was started in 1982 and has rapidly grown to become one of the largest programmes in southern Africa. This paper describes the 387 patients admitted to the unit between June 1986 and July 1988 and evaluates the effects of a combined exercise training and lifestyle modification programme. The mean age on admission was 55 years for males and 58 years for females. Most patients were from social classes I and II. Myocardial infarction, coronary artery bypass graft and a combination of both were the most common reasons for admission (35.4%, 23% and 21.2% respectively). On admission 72.9% of patients were smokers, 26.3% had hypertension and 34.3% had hypercholesterolaemia. A 50% drop-out rate within 12 months of starting the programme was noted. An increase in peak oxygen uptake, weight and skinfold thickness reduction, and improvement in the lipogram were seen after 6 months in patients who complied well with the programme. Cardiac rehabilitation is a secondary preventive strategy that can complement traditional medical and surgical therapies.

Exercise-related cardiac arrest in cardiac rehabilitation. The Johannesburg experience.

Prescribed physical activity plays a major role in the rehabilitation of patients with coronary artery disease, and as with any other form of treatment its benefits must be weighed against its possible risks. This study attempted to establish the safety of cardiac rehabilitation as a medical intervention at the Johannesburg Cardiac Rehabilitation Centre from its inception in September 1982 to July 1988, and analyses the medical status of patients who suffered a cardiac arrest (CA) in order to determine possible factors predictive of sudden death. Between September 1982 and July 1988, 1,574 patients were admitted to the unit; 480,000 man-hours of exercises were accumulated with 4 episodes of CA, giving an incidence of CA of 1/120,000 patient-hours. Three of the 4 episodes were fatal, giving an incidence of fatal CA of 1/160,000 patient-hours. This incidence is acceptably low and comparable with other cardiac rehabilitation programmes, making exercise as prescribed at the Johannesburg Cardiac Rehabilitation Centre a safe form of medical intervention. Patients at risk of CA during exercise were essentially not identifiable, since they did not come from a group currently recognised as at particularly high risk. A combination of inferior infarction with occluded dominant right coronary artery, good collateralisation and asymptomatic ischaemia was present in all CA patients. The likelihood of these pathological features being predictors of exercise-related sudden death requires further investigation.

AIDS and tuberculosis.

The diagnostic and therapeutic implications of human immunodeficiency virus (HIV) infection and tuberculosis in South Africa, where tuberculosis remains a major health problem, are reviewed. Mycobacterium tuberculosis is a high-grade pathogen and is able to establish infection early in immunodeficiency. With HIV infection showing significant entry into the heterosexual population in the RSA, an increasing number of cases with both infections can be expected to occur. The radiological appearance in combined infection is variable, ranging from a formal cavitatory picture to the more common finding of diffuse pulmonary infiltration. Intrathoracic adenopathy is a more specific sign of tuberculosis in HIV infection, since it is not associated with persistent generalised lymphadenopathy and pulmonary opportunistic infections, such as Pneumocystis carinii pneumonia. Intercurrent pneumonic infections and other pulmonary manifestations of HIV disease render the interpretation of new infiltrates on chest radiography problematical. Tuberculin skin testing remains useful in HIV infection and should be performed in all HIV-infected patients. The value of tuberculosis serology still remains questionable. Standard antituberculosis drug regimens are effective, but maintenance treatment must be continued for life and should include isoniazid and rifampicin. BCG vaccination is recommended routinely at birth in infants with HIV infection and for asymptomatic HIV-infected individuals who have not previously been immunised.