Juan Arbiza

Respiratory syncytial virus: Changes in prevalence of subgroups A and B among Argentinian children, 1990–1996

The frequency of respiratory syncytial virus (RSV) and the distribution of subgroups A and B strains during 7 consecutive years (1990–1996) were examined in two cities of Argentina. Nasopharyngeal aspirates from 1,304 children less than 2 years of age hospitalized with acute lower respiratory infection were studied by indirect immunofluorescence. RSV was detected in 352 cases (26.9%), and the peak activity was observed in midwinter. Subgroup characterization was performed with two monoclonal antibodies against the F protein on nasopharyngeal aspirate smears. Of 195 samples, 174 (89.2%) were identified as subgroup A strains and 21 (10.8%) as subgroup B. Both strains cocirculated during 5 of 7 years studied with subgroup A predominating. Subgroup A occurred at least 8 times as often in all years except for 1994–1995. Children infected by subgroup A were younger than those infected by subgroup B (P < 0.05). The association of subgroup A infection with bronchiolitis and subgroup B with pneumonia was statistically significant (P < 0.03). J. Med. Virol. 61:275–279, 2000.

Cytotoxic, Virucidal, and Antiviral Activity of South American Plant and Algae Extracts

Herpes simplex virus type 1 (HSV-1) infection has a prevalence of 70% in the human population. Treatment is based on acyclovir, valacyclovir, and foscarnet, three drugs that share the same mechanism of action and of which resistant strains have been isolated from patients. In this aspect, innovative drug therapies are required. Natural products offer unlimited opportunities for the discovery of antiviral compounds. In this study, 28 extracts corresponding to 24 plant species and 4 alga species were assayed in vitro to detect antiviral activity against HSV-1. Six of the methanolic extracts inactivated viral particles by direct interaction and 14 presented antiviral activity when incubated with cells already infected. Most interesting antiviral activity values obtained are those of Limonium brasiliense, Psidium guajava, and Phyllanthus niruri, which inhibit HSV-1 replication in vitro with 50% effective concentration (EC50) values of 185, 118, and 60 μg/mL, respectively. For these extracts toxicity values were calculated and therefore selectivity indexes (SI) obtained. Further characterization of the bioactive components of antiviral plants will pave the way for the discovery of new compounds against HSV-1.

Distribution of human papillomavirus genotypes in Paraguayan women according to the severity of the cervical lesion.

The incidence of cervical cancer in Paraguay is among the highest in the world. This study aimed to determine the distribution of human papillomavirus (HPV) genotypes in Paraguayan women, according to the severity of the cervical lesion. This cross‐sectional study included 207 women without a squamous intraepithelial lesion, 164 with low‐grade squamous intraepithelial lesions, 74 with high‐grade squamous intraepithelial lesions, and 41 with cervical cancer. Type‐specific HPV was determined by the polymerase chain reaction with MY9/11 L1 and GP5+/GP6+ L1 primers, followed by restriction fragment length polymorphism and reverse line blotting hybridization, respectively. In total, 12 high‐risk and 24 low‐risk HPVs types were detected. HPV 16 was the most prevalent, followed by HPV 18 in cervical cancer (14.6%), HPV 31 in high‐grade squamous intraepithelial lesions (14.9%), HPVs 58/42 in low‐grade squamous intraepithelial lesions (9.1% each), and HPVs 31/58 (2.4% each) in women without squamous intraepithelial lesions. Among 285 positive samples, 24.2% harbored multiple HPV types, being this more prevalent in women with squamous intraepithelial lesions (30.8% in low‐grade squamous intraepithelial lesions, 22.5% in high‐grade squamous intraepithelial lesions, and 22.0% in cervical cancer) than in women without lesions (9.3%). The higher prevalence of HPV 16 and other high‐risk HPVs in women both with and without cervical lesions may explain the high incidence of cervical cancer in Paraguay. This information may be of importance for local decision makers to improve prevention strategies. In addition, these results may be useful as baseline pre‐vaccination data for a future virological surveillance in Paraguay. J. Med. Virol. 83:1351–1357, 2011.

Molecular detection and genetic variability of human metapneumovirus in Uruguay.

Human metapneumovirus (hMPV) has been described as circulating among the Uruguayan population at least since 1998 based on serologic evidence. However, no isolation attempts, molecular detection, or genetic studies have been carried out so far in the country. In the present study, molecular detection of circulating hMPV in children hospitalized with acute respiratory tract infection in Montevideo–Uruguay was carried out by reverse transcription‐polymerase chain reaction (RT‐PCR) amplification of the hMPV nucleoprotein (N) gene from 217 nasopharyngeal aspirates. Genetic variability analysis of the positive samples was performed by amplification and sequencing of both N and attachment glycoprotein (G) genes. Eighteen of the 217 samples tested positive for hMPV, with tachypnea, chest indrawing, and wheezing being the main clinical symptoms recorded. Phylogenetic analysis of N and G genes showed that Uruguayan samples clustered in genotypes described previously as A2, B1, and B2, with bootstrap values ≥98%. Sublineages A2a and A2b could also be distinguished within the samples that belong to A2. This is the first molecular report on the circulation of hMPV in Uruguay. The pattern of circulation of this virus, analyzed for both N and G genes independently, resembles the complex evolutionary pattern of respiratory syncytial virus (RSV). J. Med. Virol. 82:861–865, 2010.

Distribution of HPV-16 variants among isolates from Paraguayan women with different grades of cervical lesion

To determine the distribution of HPV‐16 variants among Paraguayan women with different grades of cervical lesions.

Human papillomavirus genotypes distribution in cervical samples from Uruguayan women.

Persistent infection with high‐risk human papillomavirus (HPV) causes cervical preneoplasic lesions and invasive cervical cancer. This study evaluated the prevalence and distribution of HPV genotypes in cervical exfoliated cells from Uruguayan women. Five hundred sixty‐eight cervical specimens were examined by PCR using MY09/11 primer set, and were genotyped by restriction enzyme digestion (RFLP). Some of the samples which remained undetermined were reanalyzed by PGMY PCR combined with reverse line blot hybridization. Overall, about 42% of samples were positive for HPV; 96% in high‐grade squamous intraepithelial lesion, 66% in low‐grade squamous intraepithelial lesion, 15% in atypical squamous cells of undetermined significance, and 19% in samples negative for intraepithelial lesion or malignancy. HPV 16 was the most commonly found genotype, followed by HPV 68 and 58. Within low risk—HPV genotypes 6, 61, and 11 were the most frequent. This is the first cross‐sectional study, accounting for prevalence and genotype distribution of HPV in Uruguayan women. J. Med. Virol. 85:845–851, 2013.

Detection of Human Bocavirus type 1 infection in Panamanian children with respiratory illness

The human bocavirus (HBoV) was added as a new member of the Parvoviridae family in 2005 upon its discovery in nasopharyngeal aspirates from children with respiratory infection. Recently, there has been increasing evidence of worldwide circulation of HBoV; however, in Latin America few studies have been conducted. In order to detect the circulation of HBoV in Panama, based on the National Flu Surveillance System, we developed this retrospective, cross‐sectional study, from January 2011 to January 2012. Children younger than 6 years old who presented with respiratory disease were enrolled in this study. Nasopharyngeal swabs were taken in sentinel surveillance sites. Samples were tested to detect mRNA from HBoV, as well as viral RNA and DNA from others respiratory viruses. A total of 1078 patients were enrolled in this study. Overall, 44 (4.1%) of the patients presented HBoV. The most common symptoms were cough (84.6%), fever (82.1%), rhinorrhea (74.4%), and sore throat (38.5%). Less than half (45.5%) of HBoV infected patients presented with monoinfection while 54.5% of cases presented with coinfection with others respiratory viruses. Both, outpatients and inpatients were included in this study. Outpatients corresponded to 52.3% of the cases and 47.7% were inpatients. Coinfection was observed in the 50% of the inpatient cases. Phylogenetic analyses indicated that the circulating strains belonged to different clades of HBoV genotype 1. Taken together, our results support the pathogenic nature of this viral agent, especially in younger children. J. Med. Virol. 88:389–394, 2016.

Genetic variability of human respiratory syncytial virus group B in Panama reveals a novel genotype BA14

In Panama, human respiratory syncytial virus (HRSV) is responsible of 20‐40% of acute respiratory infections in children under 5 years old. Currently, little is known about the genetic variability of HRSV in Central America and the Caribbean. Recently, we reported the genetic variability of HRSV‐A, however; no studies on HRSV‐B in Panama have been described yet. In this study, 24 sequences of Panamanian HRSV‐B, from children (<5 years) with acute respiratory infections (ARI), collected from July 2008 to November 2012 were analyzed. All sequences share the characteristic 60‐nt duplication of the BA strains. Six Panamanian strains grouped with the BA10 genotype and 12 samples clustered together in a separate monophyletic clade with an aLRT support value of 0.92 and an intra‐group p‐distance less than 0.07. This fulfills the criteria to consider a new genotype in HRSV, which we named BA14 genotype. Another six strains remain unclassified, but closely related to BA9, BA11, or the new BA14 genotypes, according to their genetic p‐distance. Different amino acid substitutions in the Panamanian HRSV‐B strains were observed, some previously described and others found only on Panamanian strains. This study contributes to the knowledge of the genetic variability and evolution of HRSV in Central America.

Hepatitis E virus in South America: The current scenario

Hepatitis E virus (HEV) is one of the most frequent causes of acute viral hepatitis of enteric transmission worldwide. In South America the overall epidemiology has been little studied, and the burden of the disease remains largely unknown. A research of all scientific articles about HEV circulation in South America until November 2017 was carried out. Human seroprevalences of HEV varied according to the studied population: blood donors presented prevalence rates ranging from 1.8% to 9.8%, while reports from HIV‐infected individuals, transplant recipients and patients on hemodialysis showed higher prevalence rates. Only 2 cases of chronic hepatitis in solid‐organ transplant patients from Argentina and Brazil have been described. Detection of HEV in the swine population is widely prevalent in the region. Anti‐HEV antibodies have also been recently documented in wild boars from Uruguay. Although scarce, studies focused on environmental and food HEV detection have shown viral presence in these kind of samples, highlighting possible transmission sources of HEV in the continent. HEV genotype 3 was the most frequently detected in the region, with HEV genotype 1 detected only in Venezuela and Uruguay. HEV is widely distributed throughout South America, producing sporadic cases of acute hepatitis, but as a possible agent of chronic hepatitis. Finding the virus in humans, animals, environmental samples and food, show that it can be transmitted through many sources, alerting local governments and health systems to improve diagnosis and for the implementation of preventive measures.

Genotypes of Human Metapneumovirus circulating during 2010-2012 in children from Panama.

Human metapneumovirus (HMPV) is a common causative agent of severe respiratory tract infections in children under 5 years old, the elderly and immunocompromised patients, being responsible for 5‐15% of all viral respiratory infections requiring hospitalization. Though HMPV was included in the surveillance program for respiratory viruses in 2010, its genotype distribution remains unknown. Herein, 45 positive samples to HMPV from children ≤5 years old were characterized by phylogenetic analysis based on N gene sequence. Results showed the co‐circulation of four sub‐lineages: A2a (8.8%), A2b (55.5%), B1 (15.6%), and B2 (20%), demonstrating the genetic heterogeneity of HMPV circulating in Panamá.