Influenza is a highly contagious, acute illness in humans. Influenza viruses have negative-sense RNA genomes and are placed in the Orthomyxoviridae family grouped into three types A, B and C on the basis of the internal nucleocapsid or the matrix protein. Droplet and airborne are the most common modes of transmission. In Humans infection appears to be direct or indirect exposure to infected live or dead poultry or contaminated environments, such as live bird markets. The outbreak can be subsided by applying biosecurity measures, controlling poultry movement, using inactivated vaccines and initiating an Avian Influenza surveillance network throughout the country.
Avian influenza virus is prevalent in live birds markets of poultry in district Rawalpindi.A survey was conducted for a period of 6 months in order to determine prevalence and trends of Avian Influenza H9 in the live birds markets of district Rawalpindi. A total of 355 samples were required to estimate retail shop level prevalence of avian influenza. Using systematic sampling method 14 butchers will be enrolled from 2 sentinel live bird market and they were visited weekly to collect samples for a period of 6 months. In each week 14 pooled samples from 70 birds (a pool of 5 swab samples and 2 serum samples from each shop was collected) was collected from both sentinel sites. Tracheal/oropharyngeal swabs will be collected from live and apparently healthy poultry birds then stored properly at 4°C (24-48hours) until processed. Data was collected from the shopkeeper in a face to face interview. A detail predesigned questionnaires were filled after taking written consent from the owner. The sample collected during the survey live birds markets of Rawalpindi district were processed for laboratory analysis. Real time RT-PCR and HA and HI tests for avian Influenza virus were conducted to diagnose sample for AIV.
The proportion estimate with 95% C.I (confidence intervals) of the overall prevalence was computed by using R software. Pattern of influenza infection in live bird markets were estimated with reference to space and time. Descriptive analysis was conducted (i.e. mean, proportion) to answer four epidemiological W’s i.e. what, who, when and where.
In present study, sero-positivity against H9 AIV was determined in district Rawalpindi. Haemagglutination (HA) assay was performed and HA titer of 1:256 was calculated, the dilutions of 8HAU was 1:32.Serum samples (n=784) were tested by HI. Out of these 784, 306 sera samples were positive (HI titer>1:8) from 2 preselected sentinel markets and 14 poultry shops, while 478 were negative (HI titer <1:8) for AI. The highest antibody titer was 1:64.
The period sero-prevalence was 39.03% (95% CI: 35.41- 42.44).Results showed thatnumber of positive was high in the month ofOctober and November then slight decreased in the month of December, January and February after that it again increased in the month of March, April and May.During the study a week with one positive result was considered positive and a week was declared negative when all samples were negative. Results showed that minimum 4 and maximum 22 weeks remained positive sample results.Fourteen shops were followed up for 28 weeks and from each shop the study 56 sera samples were collected throughout the study. In 14 shops, highest prevalence was 48.21% and lowest was 28. 57%
It is concluded that avian influenza is circulating in Live Bird Markets in district Rawalpindi. This process shared that this market could perpetuate and transmit avian Influenza to Human. So these markets are the hot spot of avian influenza infection.