Influenza-Like Illness Sentinel Surveillance in Peru

Abstract

BackgroundAcute respiratory illnesses and influenza-like illnesses (ILI) are a significant source of morbidity and mortality worldwide. Despite the public health importance, little is known about the etiology of these acute respiratory illnesses in many regions of South America. In 2006, the Peruvian Ministry of Health (MoH) and the US Naval Medical Research Center Detachment (NMRCD) initiated a collaboration to characterize the viral agents associated with ILI and to describe the clinical and epidemiological presentation of the affected population.Methodology/Principal FindingsPatients with ILI (fever ≥38°C and cough or sore throat) were evaluated in clinics and hospitals in 13 Peruvian cities representative of the four main regions of the country. Nasal and oropharyngeal swabs, as well as epidemiological and demographic data, were collected from each patient. During the two years of this study (June 2006 through May 2008), a total of 6,835 patients, with a median age of 13 years, were recruited from 31 clinics and hospitals; 6,308 were enrolled by regular passive surveillance and 527 were enrolled as part of outbreak investigations. At least one respiratory virus was isolated from the specimens of 2,688 (42.6%) patients, with etiologies varying by age and geographical region. Overall the most common viral agents isolated were influenza A virus (25.1%), influenza B virus (9.7%), parainfluenza viruses 1, 2, and 3, (HPIV-1,-2,-3; 3.2%), herpes simplex virus (HSV; 2.6%), and adenoviruses (1.8%). Genetic analyses of influenza virus isolates demonstrated that three lineages of influenza A H1N1, one lineage of influenza A H3N2, and two lineages of influenza B were circulating in Peru during the course of this study.ConclusionsTo our knowledge this is the most comprehensive study to date of the etiologic agents associated with ILI in Peru. These results demonstrate that a wide range of respiratory pathogens are circulating in Peru and this fact needs to be considered by clinicians when treating patients reporting with ILI. Furthermore, these data have implications for influenza vaccine design and implementation in South America.

Rapid Detection of Respiratory Tract Viral Infections and Coinfections in Patients with Influenza-Like Illnesses by Use of Reverse Transcription-PCR DNA Microarray Systems

“…Our levels of positive detection appeared to be in accordance with those obtained in these two studies. However, our incidence data appeared to be higher than those obtained in the Peruvian study (68.4% versus 43%; P Ͻ 0.001) (22); this could be explained by the larger number of common and newly discovered respiratory pathogens potentially detectable by the RT-PCR DNA microarray detection systems as well as by the high sensitivity of this detection technology, allowing limits of detection ranging from 10 to 100 copies of viral genomes per amplification tube. Interestingly, in the present study, influenza A/H1N1v virus was detected in only 30 (31%) of the 95 tested patients, and influenza A/H3N2 virus was detected in only 2 (2.1%) of the 95 tested patients (Fig.…”

“…Numerous previous studies detected the presence of influenza viruses in the respiratory tracts of ILI patients by use of real-time RT-PCR systems during 2007 to 2008 (18,30,41,42). These studies reported levels of positive influenza A virus seasonal strain detection ranging from 25% in Peru to 40% in Greece (18,22). Our level of influenza A virus detection (33.1%) appears to be in agreement with previous published worldwide studies (17,22,30,41,42 Interestingly, the combination of two RT-PCR DNA microarray systems allowed us to detect not only influenza A virus strains but also 17 other common or newly discovered respiratory viruses in the same sample.…”

“…Influenza-like illnesses (ILI) can be attributed to a wide range of respiratory viruses, including seasonal A and B influenza viruses, the new pandemic A/H1N1v influenza virus strain, adenoviruses, respiratory syncytial virus (RSV), enteroviruses (EVs), human rhinoviruses (HRVs), human metapneumovirus (HMPV), human bocaviruses (HBoVs), coronaviruses (CoVs), and parainfluenza viruses (PIVs) (19,22,27,28,29,34,37,40,43). Patients infected by these diverse viral pathogens develop widely overlapping symptoms which render clinical diagnosis unreliable and severely limit etio-epidemiological studies (22).…”

“…Patients infected by these diverse viral pathogens develop widely overlapping symptoms which render clinical diagnosis unreliable and severely limit etio-epidemiological studies (22). The predominant pathogens of ILI are typically the influenza viruses, which cause annual recurrent epidemics affecting an estimated 5 to 15% of the population presenting with upper respiratory tract infections worldwide (29,40).…”

Viajeros a América del Sur

“…América del Sur presenta diversos tipos de circulación de los virus gripales, en los países templados, la circulación es estacional y limitada a la estación invernal mientras que en los países con clima tropical, los virus circulan durante todo el año, pero con uno o dos picos de actividad que coinciden con las épocas de lluvia. En algunos países existen diferencias en la estacionalidad de la infl uenza [41][42][43][44] . La incidencia anual de tuberculosis es muy variable entre los países de la región 45 .…”