Poultry infected with avian influenza or Tembusu virus? Identification and prevention and control methods
In early 2018, Taiwan, China reported an outbreak of a novel avian influenza, and for a time the breeding community was abuzz with discussion: was this the common highly pathogenic avian influenza, or was a relatively unfamiliar flavivirus, Tembusu virus, at work? For farmers, figuring out the pathogen is the first step in prevention and control, so today let's talk about these two easily confused poultry diseases.
What is the origin of Tembusu virus
Tembusu virus belongs to the Flaviviridae family, genus Flavivirus, and is a "distant relative" of Japanese encephalitis virus. It was first discovered in duck flocks in eastern China and mainly harms laying ducks and breeder ducks. The most typical manifestation in infected duck flocks is a sharp drop in the laying rate, smaller eggs, and thinner and softer eggshells, with feed intake also declining accordingly; some ducklings may also show neurological symptoms, such as head tilt, circling, and unsteady standing. The good news is that the mortality rate of Tembusu virus is generally not high, and most duck flocks can gradually recover egg production after enhanced care, but the impact on breeding profitability is still considerable.
How to distinguish it from avian influenza
The threat of avian influenza to poultry is clearly more ferocious, especially highly pathogenic strains, which often cause rapid onset and fast spread. Sick birds often show respiratory symptoms, head swelling, and bleeding of the foot scales, and the mortality rate rises significantly. Tembusu virus, by contrast, is mainly characterized by a drop in egg production, with hemorrhagic lesions and mortality proportions relatively milder. However, judging from external appearance and necropsy changes, the two have both overlaps and differences, and it is very easy to misjudge based on experience alone. For example, a sudden drop in egg production in a duck flock may be caused by Tembusu, or by mild avian influenza or other factors, and a final diagnosis must rely on laboratory pathogen testing and antibody monitoring. This also reminds us: when abnormalities occur, collect samples and send them for testing immediately, and do not rush to draw conclusions.
What should farms do
Regardless of which pathogen it ultimately is, the approach to prevention and control is actually similar. First, adhere to closed management and all-in-all-out, strictly prevent vehicles, personnel and wild birds from bringing the virus onto the farm, and do a good job of quarantine and isolation in the introduction and transport links. Second, Tembusu virus is somewhat associated with mosquito transmission, so in summer and autumn, focus on mosquito elimination in the farm area, clearing standing water and other environmental sanitation work. Third, vaccines are currently available for both avian influenza and Tembusu disease, but the specific immunization program should be formulated according to local epidemic conditions and veterinary guidance, and cannot simply copy someone else's plan. Last and most important: if a suspected outbreak is found, be sure to report it promptly to the local animal husbandry and veterinary department in accordance with regulations, and do not conceal it or handle dead birds privately. This is both being responsible for yourself and being responsible for the entire industry. Epidemic updates should be based on official releases, do not spread rumors and do not believe rumors, and scientific prevention and control is the real key.