(d)++Pathogens+-+overview

(7) What is a pathogen? A pathogen is an organism or virus that causes a disease in any other organism (8) Draw up a table to show one example of a pathogen from each of the following group (virus, bacteria, fungi, protozoa, flat worms & round-worms).  - ** Viruses ** : HIV   o Targets T cells* of the immune system and can also attack cells of the brain, nervous system, digestive system, lymphatic system, and other parts of the body   o Immune system is made up of specialized cells in the bloodstream. T cells are the white blood cells that identify invaders and fight off various bacteria virus, cancers, fungi, and parasites  o This virus reproduces quickly once it moves into a T-Cell and overtime, can infect all of the T-cells. =T cell= //noun, plural: T cells// A type of [|white blood cell] that functions in [|cell-mediated immunity], and is distinguished from other types of [|lymphocytes] by the presence of special [|receptor] ([|T cell receptor]) on the [|cell surface]
 * __(d) Pathogens - overview __**
 * Note:
 * Definition**

 - ** Bacteria ** : Cholera   o It is an infectious disease caused by a bacterial toxin that affects the absorption of water in the small intestine   o In severe cases, it produces violent diarrhea within only a few days. The dangerous aspect of cholera is the vast loss of fluid that can occur in a short space of time  - ** Protozoa ** : Malaria   o Malaria can lay dormant in the liver or can start to rapidly multiply. Eventually, the parasites multiply so much that the liver cells they have invaded bursts, which gets released into the blood. They then attack the red blood cells, which causes the person to experience symptoms such as high fever and chills.  - ** Fungi ** : Ringworm   o A ringworm is a fungus infection of the scalp or skin. The fungal infection is caused by mold-like fungus called dermatophytes. They live on dead tissues on the skin and any structures that grow from the skin, such as hair or nails. A ringworm is not a “worm” infection. - **Flatworms: ** pork tapeworm  o They are large, flat worms that live in the intestine. If untreated human waste is released into the environment, the eggs may be ingested by intermediate host such as pigs. The eggs hatch into larvae in the intermediate host and invade the intestinal wall and are carried through the blood stream and other tissues. Humans acquire the parasite by eating this in raw or undercooked pork. <span style="display: block; line-height: normal; margin: 0in 0in 0pt 0.5in; mso-add-space: auto; mso-list: l0 level1 lfo1; text-indent: -0.25in; vertical-align: middle;"> - ** Roundworms ** : Hookworm  <span style="display: block; line-height: normal; margin: 0in 0in 0pt 1in; mso-add-space: auto; mso-list: l0 level2 lfo1; text-indent: -0.25in; vertical-align: middle;"> o Adult hookworm lives in the small intestine  <span style="display: block; line-height: normal; margin: 0in 0in 0pt 1in; mso-add-space: auto; mso-list: l0 level2 lfo1; text-indent: -0.25in; vertical-align: middle;"> o It latches onto the intestine using 6 sharp teeth where it feeds by sucking blood through the intestinal wall

(9) List the 6 key methods by which pathogens… (a) Are transmitted. Direct transmission -from host to host --tranmitted via blood,semen, saliva

Indirect transmission -via inanimate objects - fomites --living agents - insects, mites, fleas, rodents (b) Gain entry into the body <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">1. Airborne/inhalation <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">2. Direct contact <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">3. Cuts <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">4. Ingestion of contaminated food or water <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">5. Sexual intercourse <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">6. Insects <span style="display: block; margin: 0in 0in 0pt 1in; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto; tab-stops: list .5in; text-indent: -0.25in;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">7. Blood transfusions <span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;">(10) Antibiotics <span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;">(a) Where do antibiotics originate? They are produced by the B cells* of the immune system in reaction to foreign antigens or cells that are foreign to the body such as bacteria or viruses =B-cell= (Science: [|haematology], immunology) a [|type] of [|lymphocyte] normally [|involved] in the [|production] of [|antibodies] to combat [|infection]. It is a [|precursor] to a [|plasma cell]. During [|infections], [|individual] **b-cell** [|clones] [|multiply] and are transformed into [|plasma cells], which [|produce] [|large] [|amounts] of [|antibodies] against a [|particular] [|antigen] on a [|foreign] [|microbe]. This [|transformation] occurs through [|interaction] with the appropriate [|cd4] [|t] helper [|cells]. [|Lymphocytes] that are capable of producing [|antibodies] in [|response] to detecting the presence of a [|particular] [[antigen.
 * Note:
 * B-cell**

<span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;">(b) How do they work? <span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;"> An antibody kills the desired bacteria but not the cells in your body. Each different type of antibiotic affects different bacteria in different ways. E.g. an antibiotic might inhibit a bacterium’s ability to construct its cell wall. When this happens, the bacterium dies instead of reproducing. At the same time, the antibiotic acts only on the bacterium’s cell wall-building mechanism, not on a normal cell’s. <span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;">(c) Why are the “human patient” cells not affected? <span style="color: black; display: block; font-family: 'Calibri','sans-serif'; font-size: 10.5pt; line-height: 115%;">(d) Explain why virus cells are not affected, and bacteria cells are. Antibiotics are drugs which kill or slow the growth of bacteria. Antibiotics block metabolic pathways of bacteria, inhibiting cell wall formation and protein synthesis, resulting in the death of foreign bacteria. However, viruses are not alive and utilize the organisms host cells to replicate, which are not targeted by antibiotics. In order to kill a virus by antibiotics human cell has to be killed as well