Disease-causing microorganisms (viruses, bacteria, fungi).

Illnesses caused by pathogens.

Bacteria evolve resistance to antibiotics due to overuse/misuse, making infections harder to treat.

An epidemic that has spread worldwide.

A widespread occurrence of an infectious disease in a community at a particular time.

TB infection where the bacteria is present but not causing symptoms and is not infectious.

TB infection that causes symptoms and is infectious.

A birth defect where a baby's head is smaller than expected, often linked to Zika virus.

Methicillin-resistant Staphylococcus aureus; a type of bacteria resistant to many antibiotics.

A disease transmitted by an arthropod vector, such as a mosquito or tick.

1. Infected mosquito bites human. 2. Plasmodium parasite enters bloodstream. 3. Parasite multiplies in liver and red blood cells. 4. Infected human is bitten by another mosquito. 5. Mosquito becomes infected and transmits parasite to another human.

1. Bacteria are exposed to antibiotics. 2. Some bacteria develop resistance through mutation or gene transfer. 3. Resistant bacteria survive and multiply. 4. Over time, resistant bacteria become dominant.

1. Person with active TB coughs or sneezes, releasing droplets. 2. Another person inhales the droplets. 3. Bacteria infect the lungs. 4. Infection can become latent or active.

1. Mosquito bites infected bird. 2. Virus multiplies in mosquito. 3. Infected mosquito bites human or animal. 4. Virus is transmitted, potentially causing illness.

1. Pathogens contaminate water sources (e.g., sewage). 2. People drink or use contaminated water. 3. Pathogens enter the body. 4. Illness develops (e.g., diarrhea, vomiting).

1. Mosquito bites infected person. 2. Virus multiplies in mosquito. 3. Infected mosquito bites another person. 4. Virus is transmitted, potentially causing illness or birth defects.

Swollen lymph nodes, fever, chills, bloodstream infection, organ failure, lung infection, and airborne transmission.

Fever, chills, headache, muscle pain, fatigue, anemia, and organ failure.

Persistent cough, chest pain, weakness, fatigue, weight loss, and fever.

Fever, headache, nausea, muscle weakness, meningitis/encephalitis (rare).

Mild fever, rash, joint pain, conjunctivitis, and microcephaly in newborns.

Diarrhea, dysentery, typhoid fever, dehydration, and vomiting.

Harder-to-treat infections, increased illness/death.

Poor sanitation leads to contamination of water sources, increasing the risk of waterborne disease outbreaks.

Deforestation can alter habitats, bringing humans into closer contact with disease vectors and increasing the risk of vector-borne diseases.

Climate change can expand the geographic range and breeding season of mosquitoes, potentially increasing the spread of diseases like malaria and Zika virus.