Magaly Martínez

Whole-genome analyses reveals the animal origin of a rotavirus G4P[6] detected in a child with severe diarrhea

Group A rotaviruses are a major cause of severe gastroenteritis in children worldwide. Currently, two rotavirus vaccines are being used in vaccination programs, and one of the factors involved in lower vaccine efficacy is the mismatch among the circulating strains and the vaccine strains. Thus, the emergence of animal strains in the human population could affect the efficacy of vaccination programs. Here we report the presence of a G4P[6] strain in a Paraguayan child presenting acute gastroenteritis in 2009. Genomic analyses revealed that the strain presents a porcine-like genome (G4-P[6]-I1-R1-C1-M1-A8-N1-T7-E1-H1), suggesting a direct animal-to-human transmission. Continuous surveillance of rotaviruses in humans and animals will help us to better understand rotavirus epidemiology and evolution.

Molecular epidemiology of norovirus strains in Paraguayan children during 2004-2005: description of a possible new GII.4 cluster.

BACKGROUND Noroviruses (NoV) have been shown to be an important cause of morbidity and mortality in children worldwide, only second after Group A rotaviruses (RVA). In Paraguay, acute gastroenteritis (AGE) is the third cause of mortality in children ≤5 years old. OBJECTIVES To analyze the presence and diversity of NoV in Paraguayan children ≤5 years old presenting AGE. STUDY DESIGN Three hundred seventy eight fecal samples, negative for pathogenic bacteria and RVA, were collected from children admitted as ambulatory and hospitalized patients in a large private hospital from Asuncion, Paraguay from 2004 to 2005. The presence and diversity of NoV was determined by two different RT-PCR strategies and nucleotide sequencing. RESULTS One hundred and sixty one samples were positive for NoV by partial amplification of the viral polymerase gene (RdRp). No seasonality or differences in the viral prevalence for the different age-groups were detected. GII and GI NoVs were associated to 58% and 42% of the infections, respectively. The genotype was determined in 18% (29/161) NoV-positive samples. The genotypes detected were: GII.4 (18%), GII.17 (18%), GII.6 (14%), GII.7 (14%), GII.3 (10%), GII.5 (3%), GII.8 (3%), GII.16 (3%), GI.3 (14%) and GI.8 (3%). Amplification of the ORF2 from the GII.4 strains showed the presence of a new GII.4 variant. CONCLUSIONS The results showed a continuous circulation of NoV in children throughout the two years of study and an extensive diversity of genotypes co-circulating, highlighting the need for better surveillance of NoV in Paraguayan children.

Viral load of human bocavirus-1 in stools from children with viral diarrhoea in Paraguay

Since their discovery, four species of human bocavirus (HBoV) have been described in patients with respiratory and gastrointestinal diseases. However, a clear causal association between HBoV-1 and gastroenteritis has not been demonstrated. In this study, we describe the detection and quantification of HBoV-1 in stools from children with acute non-bacterial gastroenteritis using quantitative polymerase chain reaction. HBoV-1 genome was detected in 10.6% of stools with frequent association with rotavirus and norovirus. The median of HBoV-1 viral load was 1.88 × 104 genome/ml, lower than previously shown in secretions of patients with respiratory infections, without any obvious association between high viral load and presence of HBoV as single agent. Thus, although HBoV-1 was frequently detected in these patients, there is no clear causal association of this agent with diarrhoea. Indeed, HBoV-1 DNA in stools of patients with gastroenteritis without respiratory symptoms may be a remnant of previous infections or associated with prolonged shedding of virus in the respiratory or digestive tracts.

Genomic characterization of a rotavirus G8P[1] detected in a child with diarrhea reveal direct animal-to-human transmission.

Group A rotavirus is a major cause of severe gastroenteritis in children and young animals. During a retrospective analysis of samples collected from Paraguayan children under 5 years old with diarrhea, and previously negative for rotavirus and norovirus, we detected the presence of bovine rotavirus sequences by viral metagenomics. Nucleic acid was extracted direct from stool sample and determined to be G8P[1]. The genomic analyzes revealed that the strain presents an Artiodactyl-like genome (G8-P[1]-I2-R2-C2-M1-Ax-N2-T6-E12-H3) suggesting a direct animal-to-human transmission.

Influenza A H1N1pdm 2009 Virus in Paraguay: Nucleotide Point Mutations in Hemagglutinin and Neuraminidase Genes are not Associated with Drug Resistance.

Influenza virus is associated with upper respiratory tract infections. The fourth influenza pandemic was declared in 2009. The aim of this study was to determine the genetic variability of the 2009 H1N1 pandemic virus circulating in Paraguay. Nasal swabs were collected from 181 patients with flu symptoms managed at the Hospital of the Medical School in Asunción, Paraguay, between August and October 2009. Virus detection was carried out by real-time reverse transcription-polymerase chain reaction, followed by sequencing of the hemagglutinin and neuraminidase genes, and phylogenetic analysis. H1N1pdm09 was detected in 14.9% (27/181) of the suspected cases. Analysis of 13 samples showed that these viruses the clustered in a single genetic group. Neither the mutation related to exacerbation of disease (D239G in hemagglutinin) nor that related to antiviral resistance (H275Y in neuraminidase), both detected in neighboring countries, were found. This genetic analysis of H1N1pdm09 will help to understand the spread of the disease.

Chagas disease: national survey of seroprevalence in children under five years of age conducted in 2008

BACKGROUND Since the early 1990s, programs to control Chagas disease in South America have focused on eradicating domiciliary Triatoma infestans, the main vector. Seroprevalence studies of the chagasic infection are included as part of the vector control programs; they are essential to assess the impact of vector control measures and to monitor the prevention of vector transmission. OBJECTIVE To assess the interruption of domiciliary vector transmission of Chagas disease by T. infestans in Paraguay by evaluating the current state of transmission in rural areas. METHODS A survey of seroprevalence of Chagas disease was carried out in a representative sample group of Paraguayans aged one to five years living in rural areas of Paraguay in 2008. Blood samples collected on filter paper from 12,776 children were tested using an enzyme-linked immunosorbent assay. Children whose serology was positive or undetermined (n = 41) were recalled to donate a whole blood sample for retesting. Their homes were inspected for current triatomine infestation. Blood samples from their respective mothers were also collected and tested to check possible transmission of the disease by a congenital route. FINDINGS A seroprevalence rate of 0.24% for Trypanosoma cruzi infection was detected in children under five years of age among the country’s rural population. Our findings indicate that T. cruzi was transmitted to these children vertically. The total number of infected children, aged one to five years living in these departments, was estimated at 1,691 cases with an annual incidence of congenital transmission of 338 cases per year. MAIN CONCLUSION We determined the impact of vector control in the transmission of T. cruzi, following uninterrupted vector control measures employed since 1999 in contiguous T. infestans-endemic areas of Paraguay, and this allowed us to estimate the degree of risk of congenital transmission in the country.