Viral etiologies of influenza‐like illness and severe acute respiratory infections in Thailand

Abstract

BackgroundInformation on the burden, characteristics and seasonality of non‐influenza respiratory viruses is limited in tropical countries.ObjectivesDescribe the epidemiology of selected non‐influenza respiratory viruses in Thailand between June 2010 and May 2014 using a sentinel surveillance platform established for influenza.MethodsPatients with influenza‐like illness (ILI; history of fever or documented temperature ≥38°C, cough, not requiring hospitalization) or severe acute respiratory infection (SARI; history of fever or documented temperature ≥38°C, cough, onset <10 days, requiring hospitalization) were enrolled from 10 sites. Throat swabs were tested for influenza viruses, respiratory syncytial virus (RSV), metapneumovirus (MPV), parainfluenza viruses (PIV) 1‐3, and adenoviruses by polymerase chain reaction (PCR) or real‐time reverse transcriptase‐PCR.ResultsWe screened 15 369 persons with acute respiratory infections and enrolled 8106 cases of ILI (5069 cases <15 years old) and 1754 cases of SARI (1404 cases <15 years old). Among ILI cases <15 years old, influenza viruses (1173, 23%), RSV (447, 9%), and adenoviruses (430, 8%) were the most frequently identified respiratory viruses tested, while for SARI cases <15 years old, RSV (196, 14%) influenza (157, 11%) and adenoviruses (90, 6%) were the most common. The RSV season significantly overlapped the larger influenza season from July to November in Thailand.ConclusionsThe global expansion of influenza sentinel surveillance provides an opportunity to gather information on the characteristics of cases positive for non‐influenza respiratory viruses, particularly seasonality, although adjustments to case definitions may be required.

Respiratory viruses in individuals with a high frequency of animal exposure in southern and highland Vietnam

“…In terms of seasonal distribution of the predominant viruses as EVs, influenza A virus, HRV and ADV, our report supports previous findings. [39][40][41][42][43] Our overall RT-PCR yield of 17.7% of viral agents in respiratory samples of the cohort members with the majority age from 16 years or above is in agreement with the diagnostic yields of previous studies. [44][45][46][47][48][49] The results suggest that it is probably because adults have acquired substantial immunity during their life, leading to the rapid clearance of the infecting viruses from their respiratory tract, thereby shortening the duration of viral shedding.…”

Peer Review #2 of "Respiratory syncytial virus, human metapneumovirus, and influenza virus infection in Bangkok, 2016-2017 (v0.1)"

“…In the present study, the seasonal distribution of influenza virus infections resembled those of RSV and hMPV infections, which was similar to data from previous studies (Richter et al, 2016;Parsania et al, 2016;Chittaganpitch et al, 2018). Although Thailand is located geographically in the northern hemisphere, the seasonality of respiratory infection is similar to that of several nearby tropical settings such as Indonesia, Malaysia, the Philippines and the Southern hemisphere countries of Australia and New Zealand (Weber et al, 1998;Paynter et al, 2015).…”

The characteristics of influenza-like illness management in Japan

“…It is therefore difficult to estimate the total number of people with the disease. The concept of influenza-like illness (ILI) adds further complexity, with other respiratory viruses such as rhinovirus and respiratory syncytial virus having similar symptoms to influenza [6][7][8]. Physicians in most countries do not use virological tests for ILI patients because many of the symptoms are mild and test results will not affect disease management.…”