Pathogens!! What are Pathogens? 12/7/14. Infectious Diseases are Caused by Pathogens

Transcription

1 Pathogens!! Copyright PEER.tamu.edu Infectious Diseases are Caused by Pathogens What are Pathogens? Pathogens are microbes (microscopic living organisms) or other agents that cause diseases. Ex: Foot and mouth disease is a highly contagious disease of cattle, swine, and other cloven-hoofed animals. 1

2 Not all microbes are pathogens!!! There are many types of microbes that are actually beneficial! Ex: Symbiotic bacteria found in our digestive systems Ex: Normal Flora on our skin Common Types of Pathogens Bacteria Fungi Viruses 1. BACTERIA Single-celled organisms that are prokaryotic. Less than 1% of the world s millions of bacteria are pathogenic. Bacteria reproduce rapidly and many give off toxins which damage body tissue. Bacteria are shaped like cocci (spheres), bacilli (rods), or spirilla (spirals). 2

3 Common Bacterial Diseases Disease Body System Symptoms Examples Dermatitis Skin Inflammation, pruritus (itching) skin lesions (bumps, blisters, scales, crusts) Keratocunjunctivitis Eye Inflammation in eye, pain, sensitivity to sunlight, tears, Otitis Externa Ear Inflammation of external ear canal with reddening, drainage and itching Rhinitis and Sinusitis Respiratory Inflammation of the membranes of the nasal passages and sinuses. Mucus nasal discharge, openmouth breathing, sneezing. Pneumonia Respiratory Deep cough and difficulty breathing Gastroenteritis Digestive Inflammation of stomach and intestines, excessive salivation, vomiting, diarrhea, straining, abdominal pain. Staphylococcus aureus Pinkeye is common name Staphylococcus aureus Staphylococcus Common Cold Staphylococcus aureus, including methicillinresistant S. aureus (MRSA), Streptococcus species Salmonella Anthrax Skin, Digestive, Respiratory Sudden death in cattle Varied in humans depending on exposure method Bacillus anthracis Food Poisoning Digestive Diarrhea, Nausea, vomiting Certain E.Coli strain Bacteria: A broad spectrum antibiotic A positive culture for Streptococcus bacteria 2. VIRUSES Flu Virus Rabies Virus Consists of a piece of genetic material (RNA) housed within a protective coat. Viruses are not cells!!! Is it living??? The virus reproduces by hijacking the cell of another organism (host). Most viruses cause disease and are specific as to which type of cell they will attack. Commonly associated with internal infections. 3

4 Common Viral Diseases Disease Body System Symptoms Examples Hepatitis General-many organs involved Vary from slight fever to death Hepatitis A, B, C Warts Skin Fibrous tumors of the skin an mucous membranes Pox Skin Skin lesions-bumps, blisters, pustules, and crusts Pneumonia Respiratory Labored or flank breathing, hard deep cough, fever, leukocytosis Human papilloma virus Small pox Chicken pox Bovine Respiratory Disease (BRD)- Mannheimia haemolytica There are MANY viruses that cause Pneumonia Meningitis and encephalitis Nervous Invfammation of the brain covering causing blindness, paralysis, wobbling, seizures, coma and delirium Encephalomyelitis, distemper, parvovirus, swine pseudorabies Rabies Nervous Throat paralysis, behavior change, aggression in later stages, lack of fear Rabies virus Viruses: Blood tests can also indicate a viral infection. Antiviral medications are being developed, but many are cost prohibitive. Vaccinations can prevent viral infections. Human Papilloma Virus (HPV) 3. FUNGI A single or multicellular microbe (eukaryotic). Most fungi are harmless (~300 species) Infects various external and internal tissues, but more common in external tissues. Microsporum-the fungus that causes ringworm. 4

5 Fungal Diseases Disease System Symptom Examples Ringworm, Jock itch Skin/Genital Circular skin lesions with hair loss, itching, bumps or blisters Microsporum Athlete s foot Skin Scaly rash, itching, burning Tinea pedis Dandruff Skin Dry, itchy scalp Flakes of dry skin appear Malassezia Yeast Infection Genital Itching, irritation, thick discharge Candida albicans Candida Overgrowth Digestive Diarrhea, dehydration, hemorrhaging Various Candida species Viruses: Anti-fungal drugs Topical medications Medicated shampoos or soaps 5