Todayโs path rounds are on ๐๐ฏ๐ข๐๐ง ๐๐ฅ๐ฎ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฏ๐ข๐๐ง ๐๐ฅ๐ฎ, or avian influenza, is a viral infection that affects many different bird species. Recently, there have been outbreaks of the strain ๐๐๐๐ across the world, which has been devastating for poultry production and wildlife species.
๐๐ก๐๐ญ ๐๐ซ๐ ๐ญ๐ก๐๐ฌ๐ ๐๐ฌ ๐๐ง๐ ๐๐ฌ?
Whenever there is a new strain of influenza out there, you will often here it referred to as H_N_, with different numbers in the blanks. This is referring to the two main ๐ฏ๐ข๐ซ๐ฎ๐ฅ๐๐ง๐๐ ๐๐๐๐ญ๐จ๐ซ๐ฌ, or factors that allow spread of the disease, that influenza has. These factors are called ๐ก๐๐ฆ๐๐ ๐ ๐ฅ๐ฎ๐ญ๐ข๐ง๐ข๐ง (hence the H) and ๐ง๐๐ฎ๐ซ๐๐ฆ๐ข๐ง๐ข๐๐๐ฌ๐ (hence the N). The number refers to the particular variant of these two virulence factors that viral strain has. Strains with hemagglutinin 5 and 7 are considered to be ๐ก๐ข๐ ๐ก๐ฅ๐ฒ ๐ฉ๐๐ญ๐ก๐จ๐ ๐๐ง๐ข๐, or very very bad viruses!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Avian influenza can affect pretty much any bird species, including wild populations. Some strains can also infect humans!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
As mentioned, this disease is caused by an influenza virus, which is transmitted between birds by ingesting contaminated material or inhaling the virus. The virus is also incredibly โstickyโ, meaning it can attach itself to surfaces like shoes, clothing, or vehicles, allowing spread to distant farms. Once a bird is infected, it can take up to 2 weeks before the bird develops clinical signs that indicate infection.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
The highly pathogenic strains of avian influenza have an extremely high ๐ฆ๐จ๐ซ๐ญ๐๐ฅ๐ข๐ญ๐ฒ (death rate) in chickens and turkeys, which can approach 100% of infected birds in some cases. One of the main cell types that the virus infects is ๐๐ง๐๐จ๐ญ๐ก๐๐ฅ๐ข๐ฎ๐ฆ, the cells lining blood vessels. This can cause hemorrhage, ๐๐๐๐ฆ๐ (leaking of fluid into tissue) and ๐ญ๐ก๐ซ๐จ๐ฆ๐๐จ๐ฌ๐ข๐ฌ (blood clots in a vessel preventing flow). Ultimately, this disrupted blood flow is what causes death in these poor birds.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
To confirm the presence of the virus, swabs can be taken of the mouth or ๐๐ฅ๐จ๐๐๐ (combined urinary, reproductive and gastrointestinal opening in birds) to detect the virusโ ๐๐๐ (kinda like DNA). The virus can also be cultured from these swabs to confirm the diagnosis.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
Unfortunately, the high mortality rate of this disease makes treatment impractical in many situations. Therefore, prevention is key! Extensive biosecurity measures are needed to keep this โstickyโ virus off of farms, including thorough cleaning of all objects (including humans!) moving between properties with birds on them. There are also some vaccines available, however they have to be specifically matched to the influenza strain.
๐๐ก๐จ๐ญ๐จ๐ฌ
1) A chicken with ๐๐ฒ๐๐ง๐จ๐ฌ๐ข๐ฌ (blue discoloration of the tissue) due to difficulty breathing.
2) An example of why cyanosis might occur! This photo shows froth and fluid accumulating in the ๐๐ข๐ซ ๐ฌ๐๐๐ฌ of a turkey, which are part of the respiratory system of birds.
3-4) Hemorrhage on the legs and ๐ข๐ง๐๐๐ซ๐๐ญ๐ฌ (dead tissue caused by thrombosis) on the comb and wattles of chickens. These are pretty classic signs of avian influenza!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Swayne DE. Avian influenza. Merck Veterinary Manual 2021.
Photos 1-4 ยฉ Noahโs Arkive contributors Williams, Jakowski licensed under CC BY-SA 4.0.
