Influenza A virus subtype H5N1 in the context of "Emergent virus"

A cytokine storm, also called hypercytokinemia, is a pathological reaction in humans and other animals in which the innate immune system causes an uncontrolled and excessive release of pro-inflammatory signaling molecules called cytokines. Cytokines are a normal part of the body's immune response to infection, but their sudden release in large quantities may cause multisystem organ failure and death.

Cytokine storms may be caused by infectious or non-infectious etiologies, especially viral respiratory infections such as H1N1 influenza, H5N1 influenza, SARS-CoV-1, SARS-CoV-2, Influenza B, and parainfluenza virus. Other causative agents include the Epstein-Barr virus, cytomegalovirus, group A streptococcus, and non-infectious conditions such as graft-versus-host disease. The viruses can invade lung epithelial cells and alveolar macrophages to produce viral nucleic acid, which stimulates the infected cells to release cytokines and chemokines, activating macrophages, dendritic cells, and others.

A wet market (also called a public market or a traditional market) is a marketplace selling fresh foods, such as meat, fish, and produce, and other consumption-oriented perishable goods in a non-supermarket setting, as distinguished from "dry markets" that sell durable goods, such as fabrics, kitchenwares and electronics. These include a wide variety of markets, such as farmers' markets, fish markets, and wildlife markets. Not all wet markets sell live animals, but the term wet market is sometimes used to signify a live animal market in which vendors slaughter animals upon customer purchase, such as is done with poultry in Hong Kong. Wet markets are common in many parts of the world, notably in China, Southeast Asia, and South Asia. They often play critical roles in urban food security due to factors of pricing, freshness of food, social interaction, and local cultures. Despite their importance in local food systems and livelihoods, wet markets often lack essential food safety infrastructure, such as cold chains, standardized hygiene practices, regular inspection, and product traceability.

Most wet markets do not trade in wild or exotic animals, but some that do have been linked to outbreaks of zoonotic diseases including COVID-19, H5N1 avian flu, severe acute respiratory syndrome (SARS), and monkeypox. Several countries have banned wet markets from holding wildlife. Media reports that fail to distinguish between all wet markets and those with live animals or wildlife, as well as insinuations of fostering wildlife smuggling, have been blamed for fueling Sinophobia related to the COVID-19 pandemic.