Background: The magnitude of chronic infection with hepatitis B virus (HBV) varies substantially between the countries. A better understanding of incidence and/ or prevalence of HBV infection and associated risk factors provides insight into the transmission of this infection in the community. The purpose of this investigation was to estimate the prevalence of and to identify the risk factors associated with chronic infection with HBV, as assessed by HBV surface antigen (HBsAg) positivity, in asymptomatic volunteer male blood donors in Karachi, Pakistan.

The objectives of this study were to assess the proportion of hepatitis C virus (HCV) reactors and to identify risk factors associated with HCV infection in volunteer blood donors in Karachi, Pakistan. Between 1 January 1998 and 31 December 2002, consecutive blood donations tested at two blood banks were used to assess the proportion of HCV sero-reactors donors. To evaluate the potential risk factors, a case-control study design was implemented to select cases and controls between 15 October 2001 and 15 March 2002. The overall seroprevalence of HCV in these blood donors was 1.8% (6349/35 1309). Trend analysis revealed a significant (P < 0.001) linear increase in proportions of HCV-seropositive donors from 1998 to 2002. Final multivariate logistic regression model showed that the cases were more likely than controls to have reported past hospitalization or to have received multiple injections. When a glass syringe was used to give therapeutic injections, it increased the adjusted odds of being HCV seropositive significantly more among cases than in controls and this relationship was stronger when injection was given by general medical practitioner than if the injection was given in hospital setting. Cases were more likely than controls to have reported sexual contact with multiple sexual partners. Primary prevention programmes focused on identified risk factors might help to curtail the spread of HCV infection in this community and in other similar settings in developing countries.

Isolated laryngeal histoplasmosis is a very rare entity. It has variable clinical presentations that might mimic both benign and malignant lesions, and is usually associated with pulmonary and other disseminated forms of histoplasmosis. Herein, we report a case of primary laryngeal histoplasmosis without the involvement of other systems in a 70-year-old Chinese man, who previously worked as a miner. He presented with a history of hoarseness for two months, with no other associated symptoms. Direct laryngoscopy revealed irregularity of the posterior onethird of both vocal folds. Histopathological examination revealed the presence of Histoplasma capsulatum on periodic acid-Schiff and Grocott's methenamine silver staining. The lesion resolved after one month of oral itraconazole treatment. However, the patient had to complete six months of antifungal treatment to prevent recurrence.

Goat pox virus was isolated during an outbreak of pox infection among goats in the Sersenk district, Iraq. The isolated virus grew on the chorioallantoic membranes of developing chick embryos and in primary lamb testis cell cultures. It was identified morphologically as a pox virus and serologically as a member of the Capripoxvirus group in the family Poxviridae. The isolated virus was designated the "Sersenk" strain.

Five types of pyocins were found in Pseudomonas aeruginosa strain 112. Production of these types was induced by UV irradiation. The pyocin activity was found to be resistant to trypsin treatment. Their molar mass was found to be 282, 251, 112, 89.1 and 54.9 kg/mol, respectively. The pyocins obtained were different from any known type (such as R, S, F) in their chemical and physical properties.