Infectious Diseases

1. Respiratory Infections:
➢ Common Cold:
- Cause: Various viruses, primarily rhinoviruses.
- Symptoms: Runny nose, sore throat, cough, congestion.
➢ Influenza (Flu):
- Cause: Influenza viruses.
- Symptoms: Fever, chills, muscle aches, cough, fatigue.
➢ Pneumonia:
- Cause: Bacteria (e.g., Streptococcus pneumoniae), viruses, or fungi.
- Symptoms: Cough, fever, chest pain, difficulty breathing.
➢ Bronchitis:
- Cause: Often viral; can be bacterial.
- Symptoms: Persistent cough, mucus production, wheezing.

2. Gastrointestinal Infections:
➢ Gastroenteritis (Stomach Flu):
- Cause: Viruses (e.g., norovirus, rotavirus), bacteria (e.g., Salmonella, E. coli).
- Symptoms: Diarrhea, vomiting, abdominal pain.
➢ Food Poisoning:
- Cause: Bacteria (e.g., Campylobacter, Listeria), viruses, or toxins.
- Symptoms: Nausea, vomiting, diarrhea, abdominal cramps.
➢ Hepatitis A:
- Cause: Hepatitis A virus.
- Symptoms: Jaundice, abdominal pain, nausea, fever.

3. Skin Infections:
➢ Impetigo:
- Cause: Bacteria (e.g., Staphylococcus aureus, Streptococcus pyogenes).
- Symptoms: Red sores or blisters, which can rupture and form a honey-colored crust.
➢ Cellulitis:
- Cause: Bacteria (e.g., Streptococcus, Staphylococcus).
- Symptoms: Redness, swelling, warmth, and pain in the affected area.
➢ Herpes Simplex Virus (HSV):
- Cause: HSV-1 (oral herpes) or HSV-2 (genital herpes).
- Symptoms: Painful sores or blisters on the skin or mucous membranes.

4. Vector-Borne Diseases:
➢ Malaria:
- Cause: Plasmodium parasites transmitted by Anopheles mosquitoes.
- Symptoms: Fever, chills, headache, and flu-like symptoms.
➢ West Nile Virus:
- Cause: West Nile virus transmitted by mosquitoes, primarily *Culex* species.
- Symptoms: Fever, headache, body aches, rash, and occasionally severe neurological symptoms such as encephalitis or meningitis.
➢ Zika Virus:
- Cause: Zika virus transmitted by *Aedes* mosquitoes, particularly *Aedes aegypti* and *Aedes albopictus*.
- Symptoms: Mild fever, rash, joint pain, conjunctivitis, and muscle pain. Pregnant women may pass the virus to their babies, leading to birth defects such as microcephaly.
➢ Dengue Fever:
- Cause: Dengue virus transmitted by Aedes mosquitoes.
- Symptoms: High fever, severe headache, retro-orbital pain, joint and muscle pain.
➢ Lyme Disease:
- Cause: Borrelia burgdorferi bacteria transmitted by Ixodes ticks.
- Symptoms: Rash (erythema migrans), fever, headache, fatigue.

5. Sexually Transmitted Infections (STIs):
➢ Chlamydia:
- Cause: Chlamydia trachomatis bacteria.
- Symptoms: Often asymptomatic; may cause discharge, burning sensation during urination.
➢ Gonorrhea:
- Cause: Neisseria gonorrhoeae bacteria.
- Symptoms: Discharge, pain during urination, pelvic pain.
➢ Syphilis:
- Cause: Treponema pallidum bacteria.
- Symptoms: Chancre sores, rashes, and systemic symptoms in later stages.

6. Viral Infections:
➢ HIV/AIDS:
- Cause: Human Immunodeficiency Virus (HIV).
- Symptoms: Flu-like symptoms initially, followed by immune system deterioration.
➢ Hepatitis B and C:
- Cause: Hepatitis B and C viruses.
- Symptoms: Jaundice, abdominal pain, chronic liver damage.
➢ Chickenpox (Varicella):
- Cause: Varicella-zoster virus.
- Symptoms: Itchy rash, fever, and fatigue.

7. Chronic Infectious Diseases:
➢ Tuberculosis (TB):
- Cause: Mycobacterium tuberculosis bacteria.
- Symptoms: Persistent cough, weight loss, night sweats, fever.
➢ Chronic Hepatitis B and C:
- Cause: Hepatitis B and C viruses.
- Symptoms: Chronic liver inflammation leading to liver damage.

8. Parasitic Infections:
➢ Giardiasis:
- Cause: Giardia lamblia parasite.
- Symptoms: Diarrhea, abdominal cramps, nausea.
➢ Toxoplasmosis:
- Cause: Toxoplasma gondii parasite.
- Symptoms: Flu-like symptoms; severe in immunocompromised individuals.

Preventive measures such as vaccination, good hygiene, safe food handling, and using insect repellent can help reduce the risk of these infections.