Stem Cell Science and Global Pandemic Alert Levels

Understanding Stem Cells and Pandemic Phases

Post-Pandemic Period Assessment

Following the pandemic, flu cases have become comparable to the usual seasonal flu patterns.

Stem Cells: Definition, Function, and Application

What Are Stem Cells?

Stem cells are progenitor cells that are self-renewing.

How Do Stem Cells Work?

Within the bone marrow, stem cells are found that reproduce identical cells through mitosis.

Where Are Stem Cells Located?

1. Cells in the blastocyst embryo state.
2. Organ-specific cells (e.g., bone marrow).

Stem Cell Capabilities

They are able to generate any cell type of the body.

Therapeutic Effect of Stem Cells

They function as restorative medicine for damaged tissues.

When Are Stem Cells Applied?

They are used in treatments, often alongside chemotherapy, to cure cancer.

Glossary of Biological and Medical Terms

State

Each of the phases through which a process passes to completion or reaches its end.

Morula

A massive sphere formed by the resulting cells of the zygote's divisions.

Zygote

A cell resulting from the union of a male sex cell with a female sex cell.

Disorders

A condition that endangers or is just under the skin.

Lines

Race (or lineage).

Pandemics: Definition and Phases

Defining a Pandemic

A pandemic is an infectious disease affecting humans over a wide geographical area.

To be designated a pandemic, the disease must show a high degree of transmission from one geographical sector to another.

The Origin of New Influenza Viruses

The new influenza virus often appears as a result of a process called antigenic variation (or antigenic shift), which causes a sudden and significant change in the Influenza A virus type.

Phases of Pandemic Alert (WHO Classification)

1. Phase 1: No virus circulating among animals that has caused human infections.
2. Phase 2: Movement among domestic or wild animals of a flu virus that has caused human infections, considered a potential pandemic threat.
3. Phase 3: Existence of an animal flu virus or a human-animal reassortant virus that has caused sporadic cases or small clusters of human cases.
4. Phase 4: Tested person-to-person transmission of an animal virus or a human-animal reassortant virus capable of causing community-wide outbreaks.
5. Phase 5: Spread of the virus from person to person in at least two countries in one WHO region.
6. Phase 6: Accompanied by the emergence of community outbreaks in at least a third country from a different region.

Post-Peak Period

The intensity of the epidemic in most countries with adequate surveillance has decreased below the level seen at the peak.