Human rhinoviruses and enteroviruses in influenza-like illness in Latin America.

BACKGROUND: Human rhinoviruses (HRVs) belong to the Picornaviridae family with high similarity to human enteroviruses (HEVs). Limited data is available from Latin America regarding the clinical presentation and strains of these viruses in respiratory disease. METHODS: We collected nasopharyngeal swabs at clinics located in eight Latin American countries from 3,375 subjects aged 25 years or younger who presented with influenza-like illness. RESULTS: Our subjects had a median age of 3 years and a 1.2:1.0 male:female ratio. HRV was identified in 16% and HEV was identified in 3%. HRVs accounted for a higher frequency of isolates in those of younger age, in particular children < 1 years old. HRV-C accounted for 38% of all HRVs detected. Phylogenetic analysis revealed a high proportion of recombinant strains between HRV-A/HRV-C and between HEV-A/HEV-B. In addition, both EV-D68 and EV-A71 were identified. CONCLUSIONS: In Latin America as in other regions, HRVs and HEVs account for a substantial proportion of respiratory viruses identified in young people with ILI, a finding that provides additional support for the development of pharmaceuticals and vaccines targeting these pathogens.

Sentinel surveillance of influenza-like illness in two hospitals in Maracay, Venezuela: 2006-2010.

BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month--86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second--higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. CONCLUSIONS/SIGNIFICANCE: Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza virus in the post-pandemic phase.

Human metapneumovirus strains circulating in Latin America.

The human metapneumovirus (HMPV) is responsible for acute respiratory tract infections in young children, elderly patients, and immunocompromised hosts. In this study, we genetically analyzed the circulating HMPV in Central and South America from July 2008 to June 2009 and characterized the strains present in this region. Samples were collected during an international collaborative influenza like illness surveillance study and then sequenced with specific primers for the HMPV G gene. Our results show that two distinct clusters of HMPV circulated in Central and South America, subtypes A2 and B2 being the predominant strains.

Sentinel surveillance of influenza-like-illness in two cities of the tropical country of Ecuador: 2006-2010.

BACKGROUND: 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. METHODOLOGY/FINDINGS: This is a prospective surveillance study of the causes of ILI based on viral culture of oropharyngeal specimens and case report forms obtained in hospitals from two cities of Ecuador over 4 years. Out of 1,702 cases of ILI, nine viral agents were detected in 597 patients. During the time of the study, seven genetic variants of influenza circulated in Ecuador, causing six periods of increased activity. There appeared to be more heterogeneity in the cause of ILI in the tropical city of Guayaquil when compared with the Andean city of Quito. CONCLUSIONS/SIGNIFICANCE: This was the most extensive documentation of the viral causes of ILI in Ecuador to date. Influenza was a common cause of ILI in Ecuador, causing more than one outbreak per year. There was no well defined influenza season although there were periods of time when no influenza was detected alternating with epidemics of different variant strains.

Circulating strains of human respiratory syncytial virus in central and south America.

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.

Isolation of low-pathogenic H7N3 avian influenza from wild birds in Peru.

Wild birds serve as natural reservoirs and sometimes harbor low-pathogenic avian influenza viruses. However, mutation of the virus can result in highly pathogenic strains, often more common among H5 and H7 genotypes. We report the isolation of a low-pathogenic H7N3 avian influenza in a Peruvian wetland.

Influenza and other respiratory viruses in three Central American countries.

BACKGROUND: Despite the disease burden imposed by respiratory diseases on children in Central America, there is a paucity of data describing the etiologic agents of the disease. AIMS: To analyze viral etiologic agents associated with influenza-like illness (ILI) in participants reporting to one outpatient health center, one pediatric hospital, and three general hospitals in El Salvador, Honduras, and Nicaragua Material & METHODS: Between August 2006 and April 2009, pharyngeal swabs were collected from outpatients and inpatients. Patient specimens were inoculated onto cultured cell monolayers, and viral antigens were detected by indirect and direct immunofluorescence staining. RESULTS: A total of 1,756 patients were enrolled, of whom 1,195 (68.3%) were under the age of 5; and 183 (10.4%) required hospitalization. One or more viral agents were identified in 434 (24.7%) cases, of which 17 (3.9%) were dual infections. The most common viruses isolated were influenza A virus (130; 7.4% of cases), respiratory syncytial virus (122; 6.9%), adenoviruses (63; 3.6%), parainfluenza viruses (57; 3.2%), influenza B virus (47; 2.7% of cases), and herpes simplex virus 1 (22; 1.3%). In addition, human metapneumovirus and enteroviruses (coxsackie and echovirus) were isolated from patient specimens. DISCUSSION: When compared to the rest of the population, viruses were isolated from a significantly higher percentage of patients age 5 or younger. The prevalence of influenza A virus or influenza B virus infections was similar between the younger and older age groups. RSV was the most commonly detected pathogen in infants age 5 and younger and was significantly associated with pneumonia (p < 0.0001) and hospitalization (p < 0.0001). CONCLUSION: Genetic analysis of influenza isolates identified A (H3N2), A (H1N1), and B viruses. It also showed that the mutation H274Y conferring resistance to oseltamivir was first detected in Honduran influenza A/H1N1 strains at the beginning of 2008. These data demonstrate that a diverse range of respiratory pathogens are associated with ILI in Honduras, El Salvador, and Nicaragua. RSV infection in particular appears to be associated with severe disease in infants in the region.

Frequency of human bocavirus (HBoV) infection among children with febrile respiratory symptoms in Argentina, Nicaragua and Peru.

BACKGROUND: Globally, respiratory infections are the primary cause of illness in developing countries, specifically among children; however, an etiological agent for many of these illnesses is rarely identified. OBJECTIVES: Our study aimed to estimate the frequency of human bocavirus (HBoV) infection among pediatric populations in Argentina, Nicaragua and Peru. METHODS: We conducted a cross-sectional study using stored samples of an influenza-like illness surveillance program. Irrespective of previous diagnosis, nasopharyngeal or nasal swab specimens were randomly selected and tested using real-time PCR from three sites during 2007 from patients younger than 6 years old. RESULTS: A total of 568 specimens from Argentina (185), Nicaragua (192) and Peru (191) were tested. The prevalence of HBoV was 10·8% (95% CI: 6·3; 15·3) in Argentina, 33·3% in Nicaragua (95% CI: 26·6; 40·1) and 25·1% in Peru (95% CI: 18·9; 31·3). CONCLUSIONS: These findings demonstrate circulation of HBoV in Argentina, Nicaragua and Peru among children with influenza-like symptoms enrolled in a sentinel surveillance program.

[Clinical and epidemiological characteristics of an influenza outbreak in military personnel-Trujillo, Peru, 2008]. / Características clínico-epidemiológicas de un brote de influenza A en personal militar de Trujillo, Perú 2008.

We describe an acute febrile respiratory infection outbreak in a military unit in Trujillo, Peru. Cases were identified using the influenza like illness (ILI) definition of the Ministry of Health. Nasal swab samples used for a rapid influenza test (RIT) and pharyngeal swab samples for viral isolation were taken. For influenza A, genotyping of a partial sequence of the hemagglutinin region was performed. The rate attack was 82.9%. Fifty-nine cases appeared between April 1 and 8, 2008; 58 came from the military unit (MU) #1 and one from the MU #2. The RIT identified 40 cases of influenza A and 43 cases were confirmed through cell culture. Isolations were genetically similar to the A H1N1 Brisbane strain. Early detection of outbreaks in confined locations such as military bases permits immediate action in preventing disease propagation.

Genetic analysis of influenza A/H1N1 of swine origin virus (SOIV) circulating in Central and South America.

Since the first detection of swine origin virus (SOIV) on March 28, 2009, the virus has spread worldwide and oseltamivir-resistant strains have already been identified in the past months. Here, we show the phylogenetic analysis of 63 SOIV isolates from eight countries in Central and South America, and their sensitivity to oseltamivir.

Características clínico-epidemiológicas de un brote de influenza A en personal militar de Trujillo, Perú 2008 / Clinical and epidemiological characteristics of an influenza outbreak in military personnel - Trujillo, Peru 2008

Se describe un brote de infección respiratoria febril aguda en una unidad militar de Trujillo, Perú. Se usó la definición de caso de síndrome gripal del Ministerio de Salud, se tomo hisopado nasal para prueba rápida de influenza (PRI) e hisopado faríngeo para aislamiento viral en cultivo celular. La genotipificación de influenza A fue por secuenciamiento genético de una región del gen de hemaglutinina teniendo como base vacunal de 2008. Se presentaron 59 casos entre el 01 y 08 de abril de 2008, la tasa de ataque fue de 82,9 por ciento. La PRI identificó a 40 casos positivos de influenza A y 43 casos fueron confirmados mediante cultivo celular. Los aislamiento fueron genéticamente similares con la cepa A H1N1 Brisbane. La detección precoz de un brote en lugares cerrados como las bases militares permite actuar de manera inmediata para prevenir su diseminación.

We describe an acute febrile respiratory infection outbreak in a military unit in Trujillo, Peru. Cases were identified using the influenza like illness (ILI) definition of the Ministry of Health. Nasal swab samples used for a rapid influenza test (RIT) and pharyngeal swab samples for viral isolation were taken. For influenza A, genotyping of a partial sequence of the hemagglutinin region was performed. The rate attack was 82.9 percent. Fifty-nine cases appeared between April 1 and 8, 2008; 58 came from the military unit (MU) number1 and one from the MU number2. The RIT identified 40 cases of influenza A and 43 cases were confirmed through cell culture. Isolations were genetically similar to the A H1N1 Brisbane strain. Early detection of outbreaks in confined locations such as military bases permits immediate action in preventing disease propagation.

Molecular characterization of adenovirus circulating in Central and South America during the 2006-2008 period.

BACKGROUND: Human Adenoviruses are recognized pathogens, causing a broad spectrum of diseases. Serotype identification is critical for epidemiological surveillance, detection of new strains and understanding of HAdvs pathogenesis. Little data is available about HAdvs subtypes in Latin America. METHODS: In this study, we have molecularly characterized 213 adenoviruses collected from ILI presenting patients, during 2006-08, in Central and South America. RESULTS: Our results indicate that 161(76%) adenoviruses belong to subgroup C, 45 (21%) to subgroup B and 7 (3%) to subtype E4.

Antiviral resistance in influenza viruses circulating in Central and South America based on the detection of established genetic markers.

BACKGROUND: Recent influenza antiviral resistance studies reveal an alarming increase in both adamantanes and neuraminidase inhibitors (NAIs) resistant viral strains worldwide, particularly in Asia, Europe and the United States. OBJECTIVES: In this study, we have evaluated influenza virus resistance in Central and South America. METHODS: Influenza viruses, isolated from symptomatic patients throughout Central and South America in 2005-2008 were analyzed for inhibitor resistance. The M2 and NA genes of influenza viruses were sequenced and resistance was inferred by comparison with published sequences and known resistant mutations. RESULTS: Our results indicate that: (i) resistance to adamantanes was seen in the majority (95.5%) of the influenza A/H3N2 isolates but only in one isolate of the influenza A/H1N1 viruses; (ii) resistance to NAIs began to be detected in A/H1N1 isolates from Central America in 2008; and (iii) none of the influenza B viruses analyzed were resistant to NAIs. CONCLUSIONS: These findings suggest a limited effectiveness of influenza inhibitors due to the detection of resistance among A/H1 and A/H3 viruses.

Avian influenza in wild birds, central coast of Peru.

To determine genotypes of avian influenza virus circulating among wild birds in South America, we collected and tested environmental fecal samples from birds along the coast of Peru, June 2006-December 2007. The 9 isolates recovered represented 4 low-pathogenicity avian influenza strains: subtypes H3N8, H4N5, H10N9, and H13N2.

Características clínicas y moleculares de un brote de influenza en dos bases militares, Tumbes-Perú, 2007 / Clinical and molecular characteristics of influenza outbreak in two miliotarybases in Tumbes, Perú 2007

Objetivo. Describir un brote de Influenza en dos bases militares en Tumbes, Perú. Material y métodos. Se utilizó la definición de caso de síndrome gripal del Ministerio de Salud en casos con menos de cinco días de inicio de síntomas. Se tomó hisopado nasal para la prueba rápida de Influenza (PRI) e hisopado faríngeo para aislamiento viral en tres líneas celulares (MDCK, VERO, LLCMK2). Para la genotipificación de Influenza B se usó un secuenciamiento parcial de la región de hemaglutinina de 898 pares de bases teniendo como base la cepa de la vacuna del 2007 (B/Florida/4/2006) y para el tipo A se analizó 958 pares de bases teniendo como referencia la cepa vacunal del 2007 (A/Brisbane/10/2007 (H3N2). Resultados. Se tomó 124 hisopados, 20 de la base militar (BM) número 1 y 104 de la BM número 2. La PRI identificó a 41 casos positivos: Flu B: 27, Flu A: 02, Flu: 12, con 62% de sensibilidad y 100% de especificidad. Finalmente, 66 casos fueron confirmados por cultivo celular, 54 Flu B y 12 Flu A. Los aislamientos de Tumbes fueron genéticamente similares con la cepa B/Texas/4/ 2006 (n=34) y A/Texas/91/2007 (H3N2)/ (n=7). Los síntomas más comunes fueron fiebre, cefalea, malestar general, tos, dolor de garganta, mialgias y rinorrea. Las medidas de control consistieron en el aislamiento de los casos identificados y el uso de mascarillas. Conclusiones. Se confirmó 66 casos de Influenza por cultivo celular. Los aislamientos tuvieron la mayor similitud genética con las cepas denominadas B/Texas/4/2006 y A/Texas/91/2007(H3N2).

Objective. To describe an Influenza outbreak in two military bases in Tumbes, department located in northern Peru. Material and methods. In patients within 5 days of symptoms the Ministry of Health case definition of Influenza-likeillness was used. Nasal swabs were taken for Rapid Influenza Test (RIT) and throat swab for viral isolation, three cell lines (MDCK, VERO, LLCMK2) were used. For Influenza B genotypification we made a partial sequencing of hemaglutinine region of 898 pair bases, having 2007 vaccine strain B/Florida/4/2006 as a model. For Influenza A genotypification we analysed 958 pair bases, having 2007 vaccine strain A/Brisbane/10/2007 (H3N2) as a model. Results. We took 124 samples, 20 from military base (MB) número 1 and 104 from MB número 2. RIT promptly identified 41 positive cases: Flu B: 27, Flu A: 02, Flu: 12, with 62% of sensibility and specificity 100%. Finally, 66 cases were confirmed by virus isolation, 54 Flu B and 12 Flu A. Genotypification showed that isolates were genetically similar to Influenza B/Texas/4/2006 (n=34) and A/Texas/91/2007 (H3N2) (n=7). Most common symptoms found were fever, headache, malaise, cough, sore throat, myalgias and rinorrheae. Control strategies consisted to identify probable cases and to isolate them in a special room and to wear facemasks. Conclusions. We confirmed 66 cases by cellular culture. Isolates were genetically similar to Influenza B/Texas/4/2006 and A/Texas/91/2007 (H3N2).

Distribución de los subtipos del VIH-1 en nueve países de América del Sur, 1995-2002 / Distribution on HIV-1 subtypes in nine countries of South America, 1995-2002

Objetivo: Determinar la distribución de los subtipos del virus de la inmunodeficiencia humana (VIH-1) y la presencia de cepas recombinantes en Argentina, Bolivia, Colombia, Chile, Ecuador, Paraguay, Perú, Uruguay y Venezuela a través de estudios epidemiológicos y de genotipificación. Materiales y Métodos: Se incluyeron a los participantes de los protocolos realizados en los nueve paises, incluyendo poblaciones de trabajadoras sexuales (TS), hombres que tienen sexo con hombres (HSH), individuos VIH positivos, gestantes y pacientes con tuberculosis (TB). Se utilizó la prueba de movilidad heteroduplex de envoltura (env HMA), ProRT, secuenciamiento completo o ambas para determinar los subtipos de VIH 1. Resultados: Se identificaron 3081 individuos positivos al VIH (de un total de 42 290voluntarios), las prevalencias oscilaban entre menos de 1 por ciento a 29 por ciento según población estudiada, siendo mayor en los HSH. Un total de 1654 muestras (54 por ciento) fueron genotipificadas. Se encontró el subtipo B en 1380 (83 por ciento) muestras, el subtipo F en 218 (13 por ciento), así como los subtipos A y C en 0,1 por ciento y 0,4 por ciento respectivamente. Se hallaron subtipos recombinantes BF en 39 muestras (2 por ciento) y formas recombinantes CRF01_AE(0,1 por ciento), CRF17_BF(0,4 por ciento) y CRF02_AG(0,1 por ciento). En Venezuela, Colombia, Ecuador, Perú, Bolivia y Chile (paises andinos) predominó el subtipo B, mientras en Argentina, Uruguay y Paraguay hubo un alto porcentaje del subtipo F. Conclusiones: En la mayoría de países andinos la epidemia de VIH-1 se concentró en los HSH con un predominio del subtipo B. El subtipo F es másfrecuente en las TS en Argentina y Uruguay. Esta información es útil para implementar planes de prevención y futuros ensayos de vacunas en esta región.

Objectives: To determine human immunodeficiency virus type 1 (HIV-1) subtype distribution, and the presence of recombinant strains in Argentina, Bolivia, Colombia, Chile, Ecuador, Paraguay, Peru, Uruguay, and Venezuela using epidemiological and genotyping studies. Materials and Methods: Participants in the studies performed in nine countries were included, amongst them female sex workers, men who have sex with men (MSM), HIV-positive individuals, pregnant women, and patients with tuberculosis (TB) were included. Envelope-base heteroduplex mobility assay (env HMA) testing was used, as well as ProRT, complete sequencing, or both for determining HIV-1 subtypes. Results: 3081 HIV positive individuals were identified (out of 42 290 volunteers), prevalences from less than 1% to 29% in the different populations studied, and it was higher among MSM. 1654 samples (54%) underwent genotyping. B subtype was found in 1380 (83%) samples, F subtype was found in 218 (13%) samples, and A and C subtypes were found in 0,1% and 0,4%, respectively. BF recombinant serotypes were found in 39 samples (2%), and CRF01_AE (0,1%), CRF17_BF (0,4%), and CRF02_AG (0,1%) were also found. In Venezuela, Colombia, Ecuador, Peru, Bolivia, and Chile (Andean countries) subtype B predominated, while in Argentina, Uruguay, and Paraguay there was a high frequency of F subtype. Conclusions: In most Andean countries, HIV-1 epidemic concentrated among MSM, who are predominantly infected with B subtype. F subtype is more frequent among female sex workers in Argentina and Uruguay. This is useful information in order to implement prevention plans and future vaccine tests in this region.