Bacte P1

• Bacteria live in a wide range of conditions and on the bodies of all animals, are more numerous than the cells of the body, and many are beneficial.
• Bacteria may harm the animal by feeding off the body cells or toxin secretion.
• Disease is defined as an alteration of the state of the body, or some of its organs, which interrupts or disturbs the proper performance of the bodily functions.
• Infection is when living agents enter an animal body and set up a disturbance of function in any part, infection is said to have occurred.
• Antibiotic resistance is common among the Enterobacteriaceae, Staphylococcus aureus, Pasteurella multocida, and Pseudomonas aeruginosa, but other pathogenic bacterial populations of veterinary importance appear to have been unaffected by antibiotic usage and are still sensitive to antibiotics.
• This increase in antibiotic resistance has led to resistant bacteria from animals contributing to the reservoir of antibiotic resistance in man's bacterial flora, potentially compromising the efficacy of antimicrobial therapy in man.
• Infectious disease is one caused by the presence in or on an animal body of a foreign living organisms, which creates a disturbance leading to the development of signs of illness.
• Some organisms are destroyed by the host tissue.
• Infections are not accomplished without resistance on the part of the host.
• Resistance is not sufficient to prevent growth and multiplication in the tissues, but the infections does not become extensive, and after a brief time the invading organisms are destroyed.
• The agent persists and makes slow headway against the resistance of the host.
• Resistance of the host is overwhelmed so quickly that the organisms multiplies in all parts and early death of the host ensues.
• Some organisms usually are eliminated in the secretions or excretions of the host.
• The diseased animal usually eliminates, in a manner that varies with the disease, the organism that causes it.
• In chronic infections, the host usually eliminates large numbers of the infecting agent.
• Contagious disease is one that may be transmitted from one individual to another by direct or indirect contact.
• The more chronic the disease becomes, the less likelihood there is that the host will continue to retain all the infecting organisms.
• Improper disposal of the dead bodies of animals may result in serious outbreaks of disease.
• These organisms are unable to cause serious damage to the host, and yet the host is unable to eliminate the organism.
• One who has had a recognized disease and who has not rid himself of the infecting agent is said to be a convalescent carrier.
• Individuals that eliminate virulent infection although they have no history of ever having suffered from the disease themselves, they are immune but are a source of great danger to others who lack the same amount of resistance are known as immune carriers or asymptomatic carriers.
• Individuals that harbor and eliminate a dangerous organism that they have picked up from close contact with another individual are known as contact carriers.
• In some instances, the organism and host reach an impasse.
• Sources of infection include direct or immediate contact with a diseased individual, contact through fomites, contact with disease carriers, and infection from soil.
• Sources of infection also include infections from food and water, air-borne infections, infections from bloodsucking arthropods, infections from organisms normally carried, and infections acquired in the laboratory.
• If the carcass is disposed of properly by incineration or deep burial, these organisms die.
• Individuals who discharge virulent organisms with their excretions, although apparently normal otherwise, are said to be carriers.
• If the disease proves fatal to the host, many of the infecting organisms are destroyed with the carcass.
• Systemic or General infection is a type of disease production by pathogenic organisms.
• Toxins are divided into three groups according to the type of organism that produces them: Phytotoxin, Zootoxins, and Bacterial toxins.
• Most toxins are thermolabile, heating to 58 to 60 C for 10 minutes will inactivate most toxins, a few are more resistant.
• All toxins deteriorate with age.
• Mutations are transferred from one bacteria to another through horizontal transmission.
• Neurotoxins are toxins that affect the nervous system, examples include tetanus and botulism.
• The feeding of low levels of antibiotics such as tetracyclines and penicillin to poultry, swine, and calves in order to promote growth has resulted in a great increase in the reservoir of bacteria that are resistant to antibiotics.
• There are four different types of horizontal transmission for the transfer of genetic information: Conjugation, Transformation, Transduction, and Transposition.
• Endotoxins are toxins that are mildly toxic to animal tissues and are contained in most bacteria.
• Exotoxins are toxins that are secreted or excreted by certain plants and animals and a few bacteria, these toxins are highly toxic to animals.
• Hemolytic toxins are toxins that affect red blood cells, examples include Streptococci spp and organisms of tetanus.
• Most toxins require a “period of incubation” before showing their poisonous effects.