food insects water human-contact (direct and indirect) airborne sexually transmitted blood or...
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Spreading of Disease
Food Insects Water Human-Contact (Direct and Indirect)
AirborneSexually TransmittedBlood or Bodily FluidsSneezing/Coughing
Food
~48million/yr 250 known diseases Caused by: bacteria, viruses or
parasites Bodies reaction to manufactured
chemicals Uncooked meat products Usually transmitted through
ingestion Foods exposed to warmer
temperature = increased growth rate of micro-organisms
Insects
Not caused by the INSECT ( but the organisms passing through their
system when they feed or bite)
Caused by many different micro-organisms
BacteriaVirusesProtozoan
Micro-organism = PathogenInsect = VectorMosquito bites a bird, bird feeds
young....
Water
Waterborne Diseases-water containing infectious viruses or bacteria (human/animal waste)
Water Washed Diseases – skin/eye infections caused by lack of clean water for washing
Water Based Diseases – spread by organisms that develop in water and become human parasites. Insufficiently cooked fish
Introduced to these micro-organisms through dirty drinking water, polluted rain water etc..
Urbanization/dam construction – create new environments for disease to spread.
Climate Change – spreading range of vectors such as mosquitoes
Direct Human Contact
Spread through direct bodily contact with an infected person.
Sexually Transmitted Diseases (S.T.Ds) ▪ Parasites – nourished from the people they
infect (medications can treat these)▪ Bacteria – 1 cell, feed from their host (anti-
biotics)▪ Viruses – complex molecules multiple once
they invade a host (some cannot be cured, but can be controlled with vaccines)
Indirect Human Contact
Open wounds or body discharges infect environment and personal belongings
AIRBORNE- pathogenic microbes small enough to be discharges from an infected person (coughing, laughing)▪ Suspended in air on dust particles
Can be inhaled or contacts the mucus membrane to infect someone
Harmful Bacteria
Can survive in the body, but outside individual cells.
Treated with antibiotics Commonly caused by: pneumococci,
staphylococci and streptococci▪ Commensals (live harmlessly on their host but
can become virulent) Give off toxins that damage tissues
▪ Aerobes – require oxygen▪ Anaerobes – grow only in absence of oxygen
(small intestine)
Bacterial Disease Streptococcal bacteria, Neisseria meningitidis,
E.coli Pathogenic bacteria reproduce and crowd out
healthy bacteria, or grow in normally sterile tissue.
Salmonella bacteria- leading cause of food poisoning▪ 2000 types of bacteria that make up salmonella that cause
illness by reproducing in the digestive tract▪ Direct contact or ingestion of something with bacteria on it
( not fully cooked chicken)▪ Reptiles and Amphibians (snakes) carry salmonella on their
skin▪ SYMPTOMS – headache, diarrhea, fever, nausea
Viruses
Not living things, but require “machinery” of living organisms to replicate (human body)
Vaccination is most common treatment for viral infections
Mostly airborne Typically a nucleic acid in a protein
coat
Viral Disease
Chickenpox, herpes and shingles Influenza (flu)– inhalation of virus
(airborne) Attacks cells in the upper respiratory
tract Spread through droplets (caugh, laugh
or talking) Symptoms – cough, fatigue, sore throat
Parasitic Organims
3 main types: Protozoa, Helminths and Ectoparasites
PROTOZOA – One-Celled Transmission through arthropod vector
(blood or tissue)▪ Mosquito bite
Transmission through fecal-oral route (living in intestine)▪ Contaminated food
Organism that lives on or in a host organism▪ Gets its food from the host
Protozoan Disease
Giardia Lamblia – flagellated parasite – colonizes and reproduces in small intestine▪ Remains confined to lumen of S.I and absorbs nutrients
from lumen▪ Transmission – ingestion of contaminated water▪ Symptoms – anorexia, nausea and bloating
Characterized by mode of transportation Flagellates Amebas Spore-Forming Ciliates
Vaccines
It is a biological preparation that improves immunity to a particular disease.
It stimulates the body’s IMMUNE SYSTEM to recognize the foreign agent, destroy it and keep record of it.
Immune System
Made up of: cells, glands, organs, and fluids located throughout the body.
Recognizes germs (antigens) and produces a protein substance called antibodies to fight antigens.
Memory Cells
Remember the original antigen and then automatically defend against the specific antigen if re-infected.
Are responsible for immunity to diseases.
Uses for Vaccines to Prevent Disease
Stimulate the production of Antibodies
Stimulate the production of Memory Cells
Resulting in Immunity to specific diseases
Passive Immunity
Is the transfer of active immunity in the form of readymade antibodies.
Provides immediate protection against an antigen.
Natural Passive Immunity
Refers to antibody-mediated conveyed to a fetus from its mother during pregnancy.
Also provided through the transfer of IgA antibodies found in breast milk.
Artificial Passive Immunity
Short-term immunization induced by the transfer of antibodies.
Used to treat acute infection and poisoning.
Active Immunity
The body’s ability to prepare itself for future infections by creating antibodies and memory cells.
Innate immune system protects an individual from pathogens regardless of experience.
Natural Active Immunity
Occurs when a person is exposed to a live pathogen and the body produces a primary immune response.
It is “natural” as it is not induced by a deliberate exposure.
Artificial Active Immunity
Is induced by a vaccine that contains an antigen.
There are 4 types of vaccinations:1. Inactivated Vaccines 2. Live attenuated Vaccines3. Toxoids 4. Subunit Vaccines