I faced many cases regarding outbreak of LPAI, in cox'sbazar region of Bangladesh, morbidity, mortality rate, some flock recovered, some flock re-infected few days(varies) interval,even month, some farmers confused with ND, even we the veterinarian also. I think it is unpredictable. Any time the disease might be very very harmful for public health & also in the industry. In my area, may be the whole country, individual farmer made decision wonself, they try to prevent the disease by using vaccination but results varies from case to case. As the mortality rate is low, nobody did concentrate their mind towards the proper solution.I knew there are many highly qualified consultant in this forum. I want to know which way is better for preventing the disease, either vaccination or improving Bio-security level ?
Bio security is the back bone of modern poultry business. To control all diseases including AI you should concentrate on Bio Security and isolating your farm from the surroundings and other farms.you control the movement to and fro.workers should not intermix with neighbors.
after that you think in vaccination and other tools.The low pathogenic AI alone under normal healthy flock is not a big issue, but when complicated with other respiratory diseases it will be harmful.
I agree with colleagues that Biosecurity is very important. You have to know which subtype of LPAI circulating in your flocks (H5 and H7 could change to HPAI). Other LPAI may not create a big problem unless associated with other bacterial and viral diseases. We isolated velogenic NDV and H9N2 in the same samples. Moreover, H9N2 which is LPAI has a genetic sequence that in some parts similar to the deadly H5N1. Therefore what ever you have of AI infections, Biosecurity is must. Vaccination may interfere with serological screening unless you have the facilities to follow DIVA strategy.
1- LOW PATHO GENIC AVIAN INFLUENZA IS LOW PATHO GENIC ONLY IN SPF AND NOT IN COMMERCIAL
H9N2 IS APOTENTIAL PATHOGEN UNDER FIELD CONDITIONS.EXA CERBATION OF LPAI IS THE FIELD PROBLEM. VACCINATION AGAINST AI PROPHYLACTICALLY IS BANNED BY NATIONAL AND INTERNATIONAL NORMS SINCE PROPHYLACTIC VACCINATION AGAINST DOES NOT CAUSES STERILIZING IMMUNITY. DUE TO VACCINATION THE AI WILL BECOME ENDEMIC. THE SAME THING HAPPENED IN INDIA. NO POULTRY FARM IN INDIA IS FREE OF LPAI. SHANK HAEMORRHAGE AND CLOACAL HAEMORRHAGE /STREAKS OF HAEMORRHAGE RESEMBLING ZEBRA MARKINGS OF RINDERPEST IS SEEN IN ALL POULTRY FARMS. THE PROBLEM IS MORE SEVERE IN BROILER UNITS. STAPHYLOCOCCI [MRSA/VRSA] IS WIDELY PREVALENT IN ENVIORNMENT OF POULTRY UNITS.FURTHER COMPLICATION IS PREVALANCE OF NEPHRO PATHOGENIC IB. AS PER WORLD PUBLISH LITERATURE OF 2012 PREVALANCE OF VARIANT ND/VARIANT IB AND VARIANT AI IS THE CURENT PROBLEM FACING THE INDUSTRY. AS SUCH VACCINATION ALONE IS NOT THE SOLUTION FOR CONTROL OF POULTRY DISEASES. BIO SECURITY SHOULD COVER FEED/ WATER AND ENVIORNMENT. IN MOST OF THE FARMS NO FEED SANITATION. ALL THE FEED INGREDIENTS ARE POSITIVE FOR E.COLI/STAPHYLOCOCCI. AS SUCH USE FORMALIN OR CLO2 IS ESSENTIAL
FURTHER SANITARY STATUS OF WATER/ FEED AND ENVIORNMENT SHOULD BE EVALUATED. LPAI CAN BE CONTROLED BY PROPER SURVEILLANCE AND VACCINATION AS DONE IN MINISOTA. APPROVED FOOD GRADE CHEMO STERILANTS FOR POULTRY ARE CHLORINE DI OXIDE. ACIDIFIED SODIUM CHLORITE AND PER ACETIC ACID. IN ADDITION MMS IS VERY EFFECTIVE
It is not easy to prevent infection with LPAI (H9N2) if it is endemic in a country or region.
To control the disease, there are many things you can do:
- Be sure that the one day old chickens having good maternal antibodies for LPAI.
- Apply good biosecurity practices at all levels of your cycle.
- Vaccinate the chickens with well known and approoved vaccines.
- Apply very good management practices at farm level from day old until slaughtering, especialy the first week and very important the brooding in the first 24 hours.
- Avoid multi age at the same farm.
- You have to decrease all types of stressors as much as you can.
- Try to vaccinate against E-coli with Poulvac E-coli vaccine during the first week of age to decrease the infection with E-coli that alwyas complicate the infection with LPAI.
- Avoid fine spray vaccination during the first 4weeks of age. ( use coarse spray or eye drop vaccination).
I hope that these practices are helpful.
Many many thanx to all for joining with valuable information. But here one thing was remain omitted that is -in every outbreak there was ND(either it was mild or severe) then other secondary infections.It is my experienced.So in my area i used to suggest the farmers ,firstly you have to protect ND,if you are able to do it, then the risk of infection of LPAI will be remain minimum.Yes of course,Bio-security protocol must be increased or developed.