HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.

BackgroundThe city of Medellin in Colombia has almost no documentation of the causes of acute respiratory infections (ARIs). As part of an ongoing collaboration, we conducted an epidemiologic surveillance for influenza and other respiratory viruses. It described the influenza strains that were circulating in the region along with their distribution over time, and performing molecular characterization to some of those strains. This will contribute to the knowledge of local and national epidemiology.ObjectivesTo analyze viral etiologic agents associated with influenza like illness (ILI) in participants reporting to one General hospital in Medelllin, Colombia.ResultsFrom January 2007 to December 2012, a total of 2039 participants were enrolled. Among them, 1120 (54·9%) were male and 1364 (69%) were under the age of five. Only 124 (6%) were older than the age of 15. From all 2039 participants, 1040 samples were diagnosed by either isolation or RT-PCR. One or more respiratory viruses were found in 737 (36%) participants. Of those, 426 (57·8%) got influenza A or B. Adenoviral and parainfluenza infections represented 19·1% and 14·9% of viral infections, respectively. Influenza A was detected almost throughout the whole year except for the first quarter of 2010, right after the 2009 influenza A pandemic. Influenza B was detected in 2008, 2010, and 2012 with no pattern detected. During 2008 and 2010, both types circulated in about the same proportion. Unusually, in many months of 2012, the proportion of influenza B infections was higher than influenza A (ranging between 30% and 42%). The higher proportion of adenovirus was mainly detected in the last quarter of years 2007 and 2010. Adenoviral cases are more frequent in participants under the age of four.ConclusionsThe phylogenetic analysis of influenza viruses shows that only in the case of influenza A/H1N1, the circulating strains totally coincide with the vaccine strains each year.

Dengue fever is the world's most important arboviral disease, presenting a wide clinical spectrum. We report for the first time in Peru, a case caused by dengue virus serotype 4 with significant gastrointestinal involvement (acute acalculous cholecystitis and acute hepatitis). In addition we carried out a review of the literature atypical presentation illustrating the importance of the characteristics of abdominal pain (right upper quadrant); presence of Murphy's sign, ultrasound, and liver enzymes levels, for appropriate diagnosis and clinical management.