Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela.

Tropical countries are thought to play an important role in the global behavior of respiratory infections such as influenza. The tropical country of Ecuador has almost no documentation of the causes of acute respiratory infections. The objectives of this study were to identify the viral agents associated with influenza like illness (ILI) in Ecuador, describe what strains of influenza were circulating in the region along with their epidemiologic characteristics, and perform molecular characterization of those strains.

Plasmodium blood-stage infections can be identified by assaying for protein products expressed by the parasites. While the binary result of an antigen test is sufficient for a clinical result, greater nuance can be gathered for malaria infection status based on quantitative and sensitive detection of Plasmodium antigens and machine learning analytical approaches.

Detection of histidine-rich protein 2 (HRP2) from the malaria parasite Plasmodium falciparum provides evidence for active or recent infection, and is utilized for both diagnostic and surveillance purposes, but current laboratory immunoassays for HRP2 are hindered by low sensitivities and high costs. Here we present a new HRP2 immunoassay based on antigen capture through a bead-based system capable of detecting HRP2 at sub-picogram levels. The assay is highly specific and cost-effective, allowing fast processing and screening of large numbers of samples. We utilized the assay to assess results of HRP2-based rapid diagnostic tests (RDTs) in different P. falciparum transmission settings, generating estimates for true performance in the field. Through this method of external validation, HRP2 RDTs were found to perform well in the high-endemic areas of Mozambique and Angola with 86.4% and 73.9% of persons with HRP2 in their blood testing positive by RDTs, respectively, and false-positive rates of 4.3% and 0.5%. However, in the low-endemic setting of Haiti, only 14.5% of persons found to be HRP2 positive by the bead assay were RDT positive. Additionally, 62.5% of Haitians showing a positive RDT test had no detectable HRP2 by the bead assay, likely indicating that these were false positive tests. In addition to RDT validation, HRP2 biomass was assessed for the populations in these different settings, and may provide an additional metric by which to estimate P. falciparum transmission intensity and measure the impact of interventions.

Group C orthobunyaviruses (GRCVs) are a complex of viruses in the genus Orthobunyavirus and are associated with human febrile disease in tropical and subtropical areas of South and Central America. While numerous GRCVs have been isolated from mosquitoes, animals, and humans, genetic analysis of these viruses is limited. In this study, we characterized 65 GRCV isolates from febrile patients identified through clinic-based surveillance in the northern and southern Peruvian Amazon. A 500 base pair region of the S segment and 750 base pair regions of the M and L segments were sequenced. Pairwise sequence analysis of the clinical isolates showed nucleotide identities ranging from 68% to 100% and deduced amino acid sequence identities ranging from 72% to 100%. Sequences were compared with reference strains of the following GRCVs: Caraparu virus (CARV), Murutucu virus (MURV), Oriboca virus (ORIV), Marituba virus (MTBV), Itaqui virus (ITQV), Apeu virus (APEUV), and Madrid virus (MADV). Sequence comparison of clinical isolates with the prototype strains based on the S and L segments identified two clades; clade I included isolates with high genetic association with CARV-MADV, and clade II included isolates with high genetic association with MURV, ORIV, APEUV, and MTBV. Genetic relationships based on the M segment were at time inconsistent with those based on the S and L segments. However, clade groupings based on the M segment were highly consistent with relationships based on microneutralization assays. These results advance our understanding of the genetic and serologic relationships of GRCVs circulating in the Peruvian Amazon.

Currently, there is a paucity of data regarding human adenovirus (HAdv) circulation in Andean regions of South America. To address this shortcoming, we report the clinical, phylogenetic, and epidemiologic characteristics of HAdv respiratory tract infection from a large sentinel surveillance study conducted among adults and children in Peru.

Group C orthobunyaviruses (family Bunyaviridae, genus Orthobunyavirus), discovered in the 1950s, are vector-borne human pathogens in the Americas. Currently there is a gap in genomic information for group C viruses. In this study, we obtained complete coding region sequences of reference strains of Caraparu (CARV), Oriboca (ORIV), Marituba (MTBV) and Madrid (MADV) viruses, and five clinical isolates from Peru and Bolivia, using an unbiased de novo approach consisting of random reverse transcription, random anchored PCR amplification, and high throughput pyrosequencing. The small, medium, and large segments encode for a 235 amino acid nucleocapsid protein, an approximately 1430 amino acid surface glycoprotein polyprotein precursor, and a 2248 amino acid RNA-dependent RNA polymerase, respectively. Additionally, the S segment encodes for an 83 amino acid non-structural protein, although this protein is truncated or silenced in some isolates. Phylogenetically, three clinical isolates clustered with CARV, one clustered with MTBV, and one isolate appeared to be a reassortant or a genetic drift resulted from the high variability of the medium segment which was also seen in a few other orthobunyaviruses. These data represent the first complete coding region sequences for this serocomplex of pathogenic orthobunyaviruses. The genome-wide phylogeny of reference strains is consistent with the antigenic properties of the viruses reported in the original serological studies conducted in the 1960s. Comparative analysis of conserved protein regions across group C virus strains and the other orthobunyavirus groups revealed that these group C viruses contain characteristic domains of potential structural and functional significance. Our results provide the basis for the developments of diagnostics, further genetic analyses, and future epidemiologic studies of group C viruses.

Early diagnosis of dengue virus (DENV) infection can improve clinical outcomes by ensuring close follow-up, initiating appropriate supportive therapies and raising awareness to the potential of hemorrhage or shock. Non-structural glycoprotein-1 (NS1) has proven to be a useful biomarker for early diagnosis of dengue. A number of rapid diagnostic tests (RDTs) and enzyme-linked immunosorbent assays (ELISAs) targeting NS1 antigen (Ag) are now commercially available. Here we evaluated these tests using a well-characterized panel of clinical samples to determine their effectiveness for early diagnosis.

Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2.