The incidence and severity of Clostridium difficile infections (CDI) have increased in Western countries. However, there are limited data regarding the epidemiology of CDI in Eastern countries. This nationwide study was conducted in 17 hospitals to determine temporal trends in CDI incidence (from 2004 to 2008) in South Korea. The total incidence of CDI in Korea was 1·7 cases/1000 adult admissions in 2004, and 2·7/1000 cases in 2008 (P = 0·028). When analysing the clinical features of 1367 CDI patients diagnosed in 2008, oral metronidazole was effective as a first-line treatment for CDI (61·9%). Relapse rate was 8·9% and complicated CDI was only observed in 3·6%. The incidence of CDI increased significantly in Korea from 2004 to 2008. Although the clinical features were milder than in Western countries, the increasing burden of CDI needs ongoing surveillance systems.

The phylogenetic and epidemic relationships of 104 clinical isolates of Clostridium difficile from three hospitals of different geographical and population sources in China were investigated by multilocus sequence typing. Twenty-two sequence types (STs) were identified, four of which, ST117, ST118, ST119 and ST129, were novel. No geographically specific and host population-specific phylogenetic lineages were found and there was no correlation between geographical origin or host population and strain genotype. ST37 was the dominant type in our survey but the four novel STs underline the high genetic diversity and unique polymorphisms in C. difficile from China.

This study aimed to examine trends in incidence, geographical distribution, and survival of classic and AIDS-related Kaposi's sarcoma (KS) in the general US population using Surveillance, Epidemiology, and End Results (SEER) tumour registries with 12 066 patients diagnosed with KS between 1975 and 2005. Although the age-adjusted standardized incidence ratio (SIR) of AIDS-related KS (1·9) during 1980–2005 was not significantly higher than that of classic KS (1·4) during 1975–2005 (P = 0·78), the trends in annual SIR rates revealed distinct patterns. While the SIR for AIDS-related KS declined across all registries from the early 1990s (4·6) to late-1990s (0·3) (P = 0·05), the SIR of classic KS remained relatively steady (1·7). In both forms the SIR of KS was highest in metropolitan areas. The 5-year survival rates for patients with AIDS-related KS improved from 12·1% (1980–1995) to 54% (1996–2005) (P = 0·05). Survival rates for patients with classic KS remained stable, ranging from 75·7% to 88·6% during the 30-year period. These results may reflect improved HIV treatment.

This study included all patients, with known HIV-1 status, admitted to hospital over a 5-year period with serum ferritin values exceeding 1500 μg/l. Markedly elevated serum ferritin levels are associated with a host of causes which poses a diagnostic dilemma, as the aetiology is often highly dependent on local epidemiology. We evaluated patients' records retrospectively to determine underlying causes of possible hyperferritinaemia. Aetiologies associated with hyperferritinaemia varied significantly depending on HIV-1 status. In patients infected with the HIV-1 virus, infectious causes predominated with Mycobacterium tuberculosis accounting for more than 50% of the patient population with an odds ratio of 17·98 (95% confidence interval 8·31–38·88) in HIV-positive compared to HIV-negative patients. Of the HIV-1-negative patients, hereditary haemochromatosis accounted for less than 2% of patients and chronic renal failure was the most common diagnosis. The finding of hyperferritinaemia should prompt determination of HIV-1 status, as this impacts significantly on aetiological epidemiology. In HIV-1-positive patients, aggressive investigation for mycobacterial infection should be undertaken in cases of combined hyperferritinaemia and positive HIV-1 serology.

Influenza causes severe illness and deaths, and global surveillance systems use different clinical case definitions to identify patients for diagnostic testing. We used data collected during January 2007–July 2010 at hospital-based influenza surveillance sites in western Kenya to calculate sensitivity, specificity, positive predictive value, and negative predictive value for eight clinical sign/symptom combinations in hospitalized patients with acute respiratory illnesses, including severe acute respiratory illness (SARI) (persons aged 2–59 months: cough or difficulty breathing with an elevated respiratory rate or a danger sign; persons aged ⩾5 years: temperature ⩾38 °C, difficulty breathing, and cough or sore throat) and influenza-like illness (ILI) (all ages: temperature ⩾38 °C and cough or sore throat). Overall, 4800 persons aged ⩾2 months were tested for influenza; 416 (9%) had laboratory-confirmed influenza infections. The symptom combination of cough with fever (subjective or measured ⩾38 °C) had high sensitivity [87·0%, 95% confidence interval (CI) 83·3–88·9], and ILI had high specificity (70·0%, 95% CI 68·6–71·3). The case definition combining cough and any fever is a simple, sensitive case definition for influenza in hospitalized persons of all age groups, whereas the ILI case definition is the most specific. The SARI case definition did not maximize sensitivity or specificity.