Infectious Diseases Overview

Infectious Diseases

• Flu (Influenza):

  • Cause: Influenza virus
  • Symptoms: Fever, muscle aches, lethargy, headache, sore throat, congestion, cough
  • Incubation period: 1-2 days
  • Pathogenesis: Infects respiratory epithelium, follows a lytic cycle
  • Constant mutation, glycoprotein spikes used for vaccines
  • Treatment: Tamiflu (Amantadine) within the first 24 hours

• Chickenpox (Varicella):

  • Cause: Varicella virus
  • Symptoms: Itchy bumps and blisters, fever; can lead to shingles later (latent infection)
  • Incubation period: 10-21 days
  • Pathogenesis: Enters via respiratory tract, then bloodstream, finally the skin
  • Highly contagious; spreads through weeping lesions and respiratory secretions
  • Prevention: Attenuated vaccine, passive immunity (immune globulin), antiviral (acyclovir)

• Measles (Rubeola):

  • Cause: Rubeola virus
  • Symptoms: Rash, fever, weepy eyes, cough, nasal discharge
  • Incubation period: 10-12 days
  • Pathogenesis: Begins in the respiratory tract, spreads to lymph nodes, then throughout the body
  • Prevention: Attenuated vaccine, administered in childhood (two doses)

• Black Death (Plague):

  • Cause: Bacteria
  • Symptoms: Sudden high fever, large lymph nodes (buboes), skin hemorrhages, bloody cough
  • Incubation period: 1-6 days
  • Pathogenesis: Transmitted via flea bites; rodents and other wild animals can be carriers
  • Prevention: Vaccine not widely used, not prevalent enough

• Infectious Mononucleosis (Mono):

  • Also known as "kissing disease"
  • Cause: Virus
  • Incubation period: 1-2 months
  • Symptoms: Fatigue, sore throat, fever, swollen lymph nodes, enlarged liver/spleen (avoid exertion), rash, aches
  • Transmission: Saliva; latent infection (asymptomatic for life)

• Tetanus (Lockjaw):

  • Cause: Clostridium Tetani bacteria
  • Symptoms: Restlessness, irritability, difficulty swallowing, muscle pain & spasms (jaw or entire body)
  • Incubation period: 3 days to 3 weeks (average 8 days)
  • Pathogenesis: Endotoxin from bacteria travels to the brain and spinal cord
  • Transmission: Soil; puncture wounds
  • Prevention: Childhood toxoid vaccine (acellular vaccine)

• Viral Meningitis:

  • Symptoms: Abrupt fever, headache, stiff neck, vomiting, rash, chest pain
  • Incubation period: 1-2 weeks (enterovirus), 2-4 weeks (mumps)
  • Cause: Primarily enteroviruses, mumps more common in unvaccinated areas
  • Transmission: Fecal-oral route
  • Prevention: Handwashing, avoiding pools, mumps vaccine

• Common Cold:

  • Cause: Rhinoviruses
  • Symptoms: Scratchy throat, nasal discharge, headache, cough
  • Incubation period: 1-2 days
  • Pathogenesis: Inhaled droplets, viruses attach to respiratory epithelium
  • Prevention: Handwashing, avoiding touching face, staying home when sick

• Hantavirus:

  • Symptoms: Fever, muscle aches, vomiting, diarrhea, cough, shortness of breath, shock
  • Incubation period: 8 days to 8 weeks
  • Cause: Zoonotic disease; field mice urine is a source
  • Symptoms: Fever, muscle aches, vomiting, diarrhea, cough, shortness of breath, shock

Foodborne Illness

• Foodborne Illness Groups at Risk: Pregnant women, older adults, young children, immunocompromised individuals

• Signs of Food Poisoning (Gastroenteritis): Diarrhea, vomiting, bloody diarrhea, fever, dehydration

• Food Intoxication: Ingesting toxins produced by existing microorganisms in food (canned food, anaerobic environments).

• Food Infection: Ingesting live microorganisms that grow in the intestines (improper cooking, cross-contamination).

• Food Poisoning Prevention:

  • Clean produce.
  • Store food properly
  • Inspect meat/seafood.
  • Prepare food properly (adequate cooking).
  • Practice sanitation (gloves, handwashing).
  • Restrict sick individuals from food handling.
  • Serve food promptly.
  • Use pure water.

Foodborne Illnesses and Pathogens

• Campylobacter jejuni: Raw/undercooked poultry, unpasteurized milk, contaminated water; causes diarrhea (bloody), abdominal cramps, vomiting, fever, tiredness.

• Clostridium botulinum (Botulism): Home-canned foods (low acidity), improperly canned commercial foods, herb oils; causes vomiting, diarrhea, blurred vision, drooping eyelids, slurred speech, dry mouth, weak muscles.

• Clostridium perfringens: Raw/undercooked meat, gravy, dried food; causes abdominal pain, watery diarrhea, vomiting, nausea.

• Escherichia coli O157:H7: Raw or undercooked meat, raw fruits/vegetables, unpasteurized milk/juice, contaminated water; causes nausea, bloody diarrhea, abdominal cramps.

• Listeria monocytogenes: Raw/inadequately pasteurized dairy, lunch meats, frankfurters; causes fever, muscle aches, nausea, diarrhea, premature delivery (pregnant women).

• Salmonella: Raw poultry, eggs, beef, fruit, alfalfa sprouts, unpasteurized milk; causes diarrhea, fever, abdominal cramps, severe headache.

• Shigella: Raw/undercooked food, flies; causes fever, tiredness, watery/bloody diarrhea, abdominal pain.

• Staphylococcus aureus: Improper refrigeration of meats, potato/egg salads, cream pastries; causes sudden nausea, vomiting, abdominal cramps.

• Vibrio cholerae (Cholera): Contaminated water, undercooked foods (floods); causes watery diarrhea, vomiting.

• Hepatitis A: Mollusks (oysters, clams, mussels, scallops, cockles), contaminated water, contaminated soda; causes jaundice, fatigue, abdominal pain, loss of appetite, nausea, diarrhea, fever.

• Norovirus: Raw/undercooked shellfish, contaminated water (cruise ship virus); causes nausea, vomiting, diarrhea, abdominal pain, headache, fever.

• Trichinella: Raw/undercooked pork, or carnivorous animals (bear meat); causes acute nausea, diarrhea, vomiting, fatigue, fever, abdominal pain.

• Giardia intestinalis (Beaver Fever): Contaminated water, uncooked foods (hikers); causes massive diarrhea, flatulence, stomach cramps.

• Aspergillus flavus: Mold (alpha-toxin); wheat, flour, peanuts, soybeans; causes liver damage and neurological issues.

Government Agencies Involved in Food Safety

• Food and Drug Administration (FDA): Ensures safety/wholesomeness of foods (processed/sold interstate, excluding meat, poultry and eggs).
• United States Department of Agriculture (USDA): Regulates meat, poultry, and eggs.
• Environmental Protection Agency (EPA): Regulates pesticides and establishes water quality standards.
• Centers for Disease Control and Prevention (CDC): Monitors foodborne illness. (more information needed)
• Federal Trade Commission (FTC): Regulates business practices, curbing false advertising, misleading pricing, and deceptive packaging/labeling.