One year of acute respiratory infection surveillance in migrant and refugee populations on the Thai-Burmese border
Session I – Turner, Paul – Poster Only
Title of Contribution:
One year of acute respiratory infection surveillance in migrant and refugee populations on the Thai-Burmese border
Author(s):
Paul Turner1,2,3, Wanitda Watthanaworawit1,2, Verena Carrara1,2, Francois Nosten1,2,3
Affiliation(s):
1Shoklo Malaria Research Unit (SMRU), Mae Sot, Thailand
2Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
3Centre for Clinical Vaccinology & Tropical Medicine (CCVTM), Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
Abstract:
Background
There are several hundred thousand migrant workers and one hundred and fifty thousand refugees living on the Thai-Burma border. Acute respiratory infections (ARI) are a significant cause of morbidity and mortality in these populations. SMRU and the US-CDC have developed the surveillance system presented here to define the burden and viral causes of ARI in the migrant and refugee populations, and to serve as an early warning system to identify ARI outbreaks.
Methods
Following a pilot study in 2007, a formal laboratory-enhanced surveillance system for cases of influenza-like illness (ILI) and pneumonia was established in January 2008 in two clinics in Tak province, Thailand: the out-patient clinic at the main hospital in Maela refugee camp and a migrant worker clinic in Wang Pha village. On two days per week at each clinic, all patients meeting case criteria for ILI or pneumonia were interviewed and a nasopharyngeal aspirate collected. All specimens were tested for the presence of human metapneumovirus (hMPV), influenza A, influenza B, and respiratory syncitial virus (RSV) by real-time RT-PCR assays.
Preliminary Result (data from 1st January to 31st December 2008 will be presented on the poster)
Two hundred and eighty five patients were reviewed and sampled, representing 5% of the total number of patients given a clinic diagnosis of ARI. One hundred and fifty four patients (54%) were seen in Maela refugee camp and the rest at Wang Pha clinic. The median age was 2 years (range 1 month to 66 years) and 56% were male. There were 73 single virus infections (6 hMPV, 22 fluA, 5 fluB, 40 RSV) and 11 dual virus infections (1 fluA+RSV, 4 fluB+RSV, 1 fluA+hMPV, 5 RSV+hMPV) detected. There were 77 cases of influenza-like illness diagnosed: a virus was detected in 23% of these cases (influenza A in 12/18 [67%]). Pneumonia was diagnosed in 208 patients and at least one virus was detected in 32% of cases (RSV in 46/66 [70%]). Influenza A virus was significantly more likely to be detected in patients aged 5 years or more (p<0.001) whereas RSV was found more often in those under 5 years (p=0.005). Treatment data was available in 221 cases (78%): nineteen patients were admitted for in-patient care (9% of cases where the outcome was known).
Conclusions/Discussion
Acute respiratory infections are common in rural SE Asia. All of the target viruses were detected, with hMPV and RSV predominating in young infants and influenza viruses being more commonly detected in older patients. Virus detection was highly season with a peak for all viruses occurring during the wet season. However, none of the tested viruses were detected in 71% of patients, suggesting other pathogens play a significant role in the aetiology of ILI and pneumonia in these populations.
