A Cluster of Pneumonia Patients in a Family related to Probable Highly Pathogenic Avian Influenza Outbreak in Poultry, Tak Province, Thailand, August 2010

Abstract

Background: On 6^th August 2010, the Bureau of Epidemiology was notified of a cluster of 5 probable human avian influenza (AI) cases following the abnormal death of their poultries. An investigation was initiated to verify diagnosis and confirmed outbreak, and find out linkage between animal-human.
Methods: We conducted a survey to identify all cases in affected villages, a probable case had Influenza Like Illness (ILI) and exposed to suspect-AI poultry (death >5% of flock); or had pneumonia or respiratory failure during 25^th July–23^th August 2010. Serum, nasal and nasopharyngeal swab from index cluster and symptomatic ILI patients were collected and sent to National Institute of Health. We collected animal samples from suspect AI poultries and patient’s house, and tested for HPAI (H5 and H7) and Newcastle disease. We interviewed patients, their families, health workers and poultry-farmers. Medical charts, laboratory records review and an environmental survey were carried out.
Results: From 300 households, 11 probable cases were found (attack rate=0.29%). In the index cluster, 60% were hospitalized and had infiltration both lungs, 60% were <5 years, 80% attended Buddhist Lent Day at a village temple, and one had positive Mycoplasma pneumoniae. All human samples were negative for influenza. All 15 animal samples were negative for HPAI. Dead poultries were eaten by farmers. The indexcluster house had poor sanitation/ventilation and close contact with low-biosecurity poultry.
Conclusions: A cluster of pneumonia patients occurred in one family. Although we could not find linkage with HPAI poultry, in order to protect public health, we suggest farmers to bury or cremate all sick poultrycarcasses as well as practice prompt notification. Community-wide education regarding biosecurity, sanitation and ventilation is needed.