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Clinical Examination for H5N1 Avian Influenza Virus Infection in Poultry |
Recently, the National Steering Committee for Avian Influenza Control issued a guideline stating: Poultry farms in outbreak regions are not required to cull their flocks if they implement effective biosecurity measures and test negative for avian influenza virus.
Similarly, concentrated farms located away from residential areas are not required to cull their flocks if they test negative for H5.
Culling All Poultry in Villages with 50% of Households Affected
According to Directive 3083 dated November 25 from the Department of Animal Health (Ministry of Agriculture and Rural Development), in cases where poultry show symptoms of illness or die under suspicious circumstances, the local veterinary unit must collect samples and send them to the district veterinary station for immediate testing, while also proceeding to cull all poultry at the outbreak site.
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Containment of the Outbreak Local authorities with outbreak sites must conduct thorough cleaning and disinfection of the entire outbreak area and within a radius of 3 km from the outbreak perimeter; disinfect all means of transportation entering and exiting the outbreak area; vaccinate all poultry in the buffer zone within a 5 km radius from the outbreak perimeter (if that area has not been vaccinated); Simultaneously, the transportation of poultry and poultry products into and out of the outbreak site and the 3 km quarantine zone is prohibited, and checkpoints must be established on main roads leading to the outbreak area, with a dedicated surveillance team on duty 24/7; warning signs must be posted in the outbreak area. |
In the case of villages, hamlets, or neighborhoods, if the outbreak occurs in one household, all poultry in that household must be culled; poultry in surrounding households must also be culled if they are free-ranging; if outbreaks occur in two or more households but are scattered within the village, all poultry in that village must be culled.
If over 50% of villages, hamlets, or neighborhoods in a commune are affected (defined as having one or more outbreak sites), then all poultry in that commune must be culled.
For farms and concentrated breeding establishments experiencing outbreaks, all poultry in those facilities must be completely culled.
In the case of natural bird sanctuaries, bird owners must promptly identify sick or dead birds for disposal by burial or incineration; samples must also be sent to the testing laboratories of the Central Veterinary Diagnostic Center, the Southern Veterinary Center in Ho Chi Minh City, and the Veterinary Institute.
Bird owners must carry out disinfection using lime and chemicals such as 2-5% formalin once a week; visitors are strictly prohibited from entering the bird sanctuary, and poultry should not be allowed to roam near these areas. Reports must be submitted to the Animal Health Department for coordinated disease monitoring.
The directors of zoos and parks must isolate poultry and ornamental birds from other animals; disinfect animal housing with lime and chemicals such as Benkozid, Virkon, etc., and promptly identify any sick or dead poultry while temporarily restricting tourist access to areas where poultry and ornamental birds are kept.
Two Methods of Culling
The Department of Animal Health (Ministry of Agriculture and Rural Development) has proposed two methods for culling poultry and ornamental birds:
– Burial of Poultry:
Use large plastic bags or jute sacks to place the poultry, securely tie the bag, and spray disinfectant before transporting to the disposal site.
Dig a burial pit 2.5-3 meters deep, with length and width depending on the number of poultry to be culled; lay a layer of plastic over the entire bottom surface and sides of the pit, and place the poultry carcasses inside. Before placing them, cut the bags to aid in decomposition. Spray disinfectant or sprinkle lime powder over the surface of the poultry layer and on the ground; the distance from the top of the poultry layer to the ground must be at least 1-1.5 meters, then compact the soil firmly over the surface.
– Incineration of Poultry:
Burn the poultry carcasses in the pit using firewood, charcoal, gasoline, or oil, then cover with soil and compact as in the burial method. Incineration can also be done using specialized incinerators.
The burial site must be located far from residential areas, schools, hospitals, markets, main roads, and drinking water sources.
Additionally, it is necessary to burn or bury waste (manure, garbage, etc.). For inexpensive materials that are contaminated, incineration is recommended. Other farming equipment that cannot be burned should be sprayed with disinfectants such as 5% Cresyl, 2-3% sodium hydroxide, or 3% formalin on all surfaces of the animal housing, floors, yards, walls, feeding troughs, drinking troughs, and ceilings. The disinfectant must be sprayed thoroughly over the surfaces being disinfected, approximately 80-120 ml/m² of area, spraying from top to bottom.
After 24 hours, clean the surfaces and equipment with water, allow to dry, and disinfect a second time. Before the outbreak is officially declared over, the entire farming area must undergo a final disinfection process. Wastewater from cleaning must be collected and disinfected before being discharged by adding lime to achieve a concentration of 10%.
The area surrounding the poultry housing must be cleared, and tools, materials, and waste must be collected for disposal, followed by spraying disinfectant as described above.
Ha Yen
