Outbreak investigation of influenza a virus H9N2 among commercial poultry flocks in Islamabad, Pakistan during 2017

Abstract

Purpose: On October 09th 2017 few suspected cases of AIV H9N2 were reported to provincial reference laboratory for poultry diseases, Poultry Research Institute (PRI), Rawalpindi from Badhana Kalan, Islamabad. The cases were pressented with complaint of respiratory distress, loss of production and unusually high mortality. The objectives of this investigation were to know the magnitude, reasons of the outbreak and to control it through targeted interventions. Methods & Materials: The team from PRI visited the affected village and adjoining areas on October 13th, 2017. Active cases finding was done in the area using a standard case definition. Meeting sessions were conducted with poultry farmers, live bird market professionals and local administration. Socio-demographic information, clinical features, risk factor information, immunization status and biosecurity practices were recorded on a pre tested questionnaire. Rates and frequencies were calculated using Epi Info™ 7 Software. Results: During active case finding 28 farms qualified as suspected for Avian Influenza H9N2 infection as per case definition, having a total poultry population of 273,100 and mortality of 16000 birds (5.86%). The mean age was 25 weeks ± 10.25 SD with a range of 47. Only 7% (2/28) of the flocks had complete vaccination. Only 39% (11/28) had the farm boundary wall and 14% (4/28) had mortality disposal pits. Similarly 32% (9/28) of the farms had restricted visitor's movements. Approximately 4% (1/28) of the farms had wheel dip at the farm entrance while 50% (14/28) had foot dip. Conclusion: AI H9N2 outbreak occurred in the area with very low vaccine coverage, regular vaccination of the flocks was recommended. Standard biosecurity measures were recommended. Farmers of the surrounding area of 3 km radius were provided with one time free vaccine to avoid spread of the disease. Immediate safe disposal of mortality was ensured. Active surveillance for detection of sero-conversion in unvaccinated flocks and flock monitoring in vaccinated flocks was started in the affected area. A seasonal alert letter on Avian Influenza was issued by PRI to sensitize the relevant stakeholders.