Types of Invaders The pathogens

Types of Invaders Antigens Microorganisms Viruses Bacteria Fungi

Viruses Not considered “living” They have no cytoplasm or organelles and therefore no cellular metabolism Needs a living host cell to survive Will take over host cell to replicate by inserting its DNA/RNA into host’s - they do not reproduce They can hide host cell beneath cell membrane, body will recognize cell as “self”

Viruses can mutate and evolve because they are made up of DNA/RNA They can only get inside of cells that they have same or similar proteins on surface (capsid) to match “self cell” by stealing pieces from previous hosts. This is why we have human viruses, dog viruses, bird viruses, etc. And why some viruses affect only certain types of cells (nerve cells, skin cells, etc.) Viral infections cannot be treated with antibiotics but some can treated with anti-viral medication (which acts to slow replication of Viral DNA/RNA) Some can be prevented with vaccines

Viruses Rhinovirus-Common Cold- over 200 strains Varicella - Chicken Pox – rarely fatal Variola – Smallpox – often fatal – but now eliminated thanks to vaccinations! Influenza – MANY different strains (Three main genera Influenza A, B, C) Human Papillomavirus – HPV – can lead to warts, cervical cancer, and some other genital cancers Rotavirus – leading cause of diarrhea among infants and young children

Smallpox Chicken Pox

Viruses Mumps – swelling of salivary glands, and testicular swelling Measles – begins as upper respiratory infection and later skin rash- can lead to diarrhea, pneumonia, encephalitis, and eye infections Rubella – rash, swollen glands Poliomyelitis – usually asymptomatic, sometimes flu-like symptoms, in less than 1% of polio cases, virus enters the CNS, destroying motor neurons, leading to muscle weakness and paralysis; highly contagious Rabies – causes encephalitis; violent movements, fear of water, can be fatal HIV-

MMR Vaccination protects against all three! Measles Mumps Rubella MMR Vaccination protects against all three!

Vaccination Administration of antigenic material to produce immunity to a disease Can be live but weakened, dead, or inactivated form of pathogen (virus or bacteria) Pathogens are grown in culture and killed/weakened, but surface proteins are intact enough to be recognized When injected, immune system will evoke a response

Bacteria Are considered a “living” prokaryotic cell Does not need a living host cell to survive Most (99%) are good (beneficial) few are harmful (pathogenic) Beneficial bacteria help us with digestion, releasing vitamins, eliminating body toxins, preventing fungal growth

Bacteria Harmful (pathogenic) bacterial infections can be treated with antibiotics Some can live harmlessly, but develop into an infection if immune system has had its resistance lowered (ex: AIDS) A few infections can be prevented with vaccines

Pathogenic Bacteria Tuberculosis – affects lungs, difficult to treat Streptococcus – affects throat (pharynx, larynx, tonsils) Botulism – weakens muscles, prevents breathing Bubonic Plague – spread by fleas that live on rats; inflames and damages lymph nodes, can kill a human in 4 days Cholera – affects small intestine, causes diarrhea, vomiting, and rapid dehydration

Pathogenic Bacteria Salmonella – can cause typhoid fever and food poisoning Escherichia Coli – aka E.Coli – some strains are beneficial, but the pathogens cause lower digestive issues (food poisoning) or UTIs Syphilis – STD that causes lesions; if left untreated, it can cause issues with the heart and brain Impetigo – skin infection

Pathogenic Bacteria Diphtheria – causes upper respiratory issues Pertussis – whooping cough Tetanus – causes muscle spasms These last three can be quite harmful (even deadly) that is why we receive the DPT vaccination

Antibiotics A substance or compound that kills or inhibits growth of bacteria Can either be made synthetically from chemicals or produced by fermenting different fungus molds Unfortunately, bacteria can mutate to become resistant to antibiotics EX: penicillin, amoxicillin, tetracycline, sulfa drugs, cefzil

Fungus Are considered a “living” eukaryotic cell Includes molds and yeasts Some are beneficial, such as fungi used to make antibiotics (penicillin) or baker’s yeast Infections can spread quickly and easily!

Pathogenic Fungi Candida – Yeast Infection, can be in the mouth (candidiasis) Tinea Pedis – Athlete’s Foot Tinea Cruris – Jock Itch Tinea Unguium – Nail Fungus