Lecture Exam 3 - Chapter 19

Second period of Infection - Prodromal Phase

2. Prodromal Phase - is the time of mild signs or symptoms. For the flu, the period is characterized by symptoms such as headaches and muscle aches. - Progression of the disease can be described by clinical or subclinical

Third Period of Infection - Acute Period

3. Acute Period/ Climax - This is the stage of the disease where signs and symptoms are super intense. Example, For the flu, patients suffer high fever and chills, dry skin and a pale complexion may result from the constriction of the skin's blood vessels to conceiver heat. A headache, cough, body and going aches, and loss of appetite are common. The length of this period depends on the body response to the pathogen and the virulence of the pathogen.

Fourth Period of Infection - Period of Decline

4. As the signs and symptoms begin to subside, the host enters a period of decline. Sweating may be common as the body release excessive heat and the normal skin color soon returns as the blood vessels dilate.

Fifth Period of Infection - Period of Convalescence

5. To conclude the body passes though the period of convalescence. During his time the body systems returns to normal

Explain the process of adhesion influencing pathogen colonization and entry into the host

- Many pathogens enter at a particular portal of entry due to the pathogens containing on their surface "sticky" factors called adhesions, that only bond to specific tissues Example A - pathogens contains pilli w/ specific adhesions to attach to the receptors of the host cell Example B - Pathogens attaches more firmly via receptors to the host cell Example C - Pathogen has formed a biofilm on the host cell and the immune response has generated an information, indicating there is an infection. * Many gram-negative bacterial species and some gram- positive species contain pilli that can adhere (bond) to a specific host cell or tissue based on the adhesions located on the pilli.

Explain the portal of entry

- A portal of entry - refers to the route by which an exogenous pathogen enters the host. Entry routes include: (1) respiratory portal (inhalation of pathogens in the air) (2) gastrointestinal portal - the fecal-oral route (ingestion of contaminated food or water) (3) a sexually transmitted portal (4) parenteral (refers to direct entry into an organism by a non-oral route) (e.g. piercing the skin or mucous membranes through cuts, animals/ insect bites, wounds, and injections)

Discuss the transmission methods for infectious disease

- Direct contact - person -to-person or horizontal transmission implies close or personal contact w/ someone who is infected or who has the disease. - Examples: handshaking kissing sexual activity respiratory droplets (sneeze & cough) animal bite or scratch vertical transmission - includes the spread of pathogens, such has HIV, from a pregnant mother to her unborn child

Define the concept of microbiota and symbiosis

- Indigenous Microbiota - resides on several body tissues including the skin, ears, eyes, upper respiratory tract, digestive system, oral - rectum cavity, urogenital orifices in both males & females - microbiota protects us from pathogen invasions creating physical barriers over epithelium of respiratory & digestive tracts - It also makes environment less hospital for pathogens by secreting anti-microbial compounds - symbiosis - is the relationship between body and microbiota

Discuss the transmission methods for indirect contact

- Indirect contact - is a result of contact w/ a non-living object or a vector - Examples: fomites - are inanimate object on or in which disease organism linger for some period of time (e.g., drinking glasses can be contaminated w/ flu and transmitted to a person when they touch the object) - vehicle transmission - spread of disease though contained food from water oral. (e.g. poultry are often reservoirs for salmonella) ex. touching a desk someone sneezed on it

Explain the essential difference between infection and disease

- Infection is the ability of the bacteria to multiply within the host. * A person can be infected without suffering a disease - Disease refers to any change from the general state of good health. * If infection leads to tissue or organ damage/ dysfunction disease will soon develop

Explain the reasons for nosocomial infections and the chains of transmission involved

- Like all infections, nosocomial infections involves 3 elements: a compromised host (the hospital patient), a source of hospital pathogens , and a chain of transmission - Compromised host : Hospital patients have some form of physical injury like as surgical wound, skin trauma or breakdown of a portal entry. Patients are also immunocompromised: that is their immune system is weakened or impaired. Should a pathogen enter the body then the patients immune system is unable to mount an attack and eliminate it. - The Hospital Pathogens: Hospital personnel attempt to maintain a sanitary and clean hospital environment. Still, the facility can be a reservoir for human pathogens. Pathogens can be spread from patients and/or from healthcare staff. Many nosocomial infections are caused by opportunistic agents, microbes that do not normally cause illness in healthy individuals, but given the "opportunity" can infect an immunocompromised patient - The chain of transmission: The key to nosocomial disease and its prevention stems from the way the agents are transmitted to the patient -- you must have PPE's ( gloves, mask, and eye protection) - paper robes -- hand washing entering and leaving the room -- double doors -- robes -- shingles is a big deal in hospitals / many people before 1980 no vaccination against chicken pox -- antibiotic resistance huge issues - use of copper bands/ has proven to be anti-bacterial and is reusable - handling and disposing of sharps (needles) properly - disposing of hazardous materials - cleaning spills w/ disinfectant and bleach solution

Explain how health care workers can stop the spread of nosocomial infections

- Nosocomial infections are serious health threats within the health care system - The key to decreasing nosocomial disease is to break the chain of transmission. Besides the use of standard precaution the CDC published methods for cleaning, disinfecting, and sterilizing medical devices. - teacher's def - infections that you get in the hospital

Compare pathogenicity and virulence, and show how microorganisms vary in their pathogenicity using the opportunistic infections as examples.

- Pathogenicity - refers to the ability of microorganisms to gain entry to the host's tissues and bring about a physiological and anatomical change. teacher's def - determines how sick an individual gets by the presence the pathogen - Determining whether or not a disease (pathogen) is mild or severe will depend on the pathogens ability to do harm to a host thus the degree of pathogenicity is called - virulence * Example - The common cold would be considered (moderately virulent) - because even though it attacks the immune system it is disease that is easier to heal but takes time. The immune system works extremely hard to bring the body back to homeostasis by giving fevers and using coughing to release; however, in the meantime opportunistic infections may occur due to the cold putting your immune system in a weakened state. Opportunistic infections occurs when your immune system is weak. This makes a person susceptible to a secondary infection a person with a cold may develop ear infections, bronchitis, pneumonia, and an asthma attack. *Aids - is another example that is highly susceptible to other opportunistic infections.

Define a reservoir, and describe the 3 types of reservoirs of disease

- The sources where the microbes live, multiply, and spread are called reservoirs of infection. - animals are one type of reservoir. A domestic dog that has rabies can transmit the virus to humans though a bite. Zoonosis is spread from animal to human. - Dead end host - can't pass on a disease. For example, the human can't be a reservoir because the individual cannot pass on the virus; there humans are dead end host - carrier- have recovered from the disease but yet continue to shed the disease of agents. teacher's def - post std's humans are the reservoirs

Explain infectious dose

- When the appropriate portal of entry has been breached, the ability of the pathogen to establish an infection and possible disease depends on the INFECTIOUS DOSE, the # of pathogens that need to be taken into the body to cause infection and possible disease

compare and contrast a clinical and subclinical disease

- a clinical disease is one in which the symptoms are accompanied by clearly recognized clinical symptoms. (influenza) - easily diagnosed - a subclinical disease is accompanied by a few obvious symptoms - overlapping symptoms of signs Example - A subclinical disease has no recognizable clinical findings. It is distinct from a clinical disease, which has signs and symptoms that can be recognized. Many diseases, including diabetes, hypothyroidism, and rheumatoid arthritis, are frequently subclinical before they surface as clinical diseases.

compare and contrast an acute and chronic disease.

- acute disease - (like the flu) develops rapidly, is usually accompanied by severe symptoms, comes to a climax, and fades quickly - quick onset and recovery - chronic disease - (like diabetes) often lingers for long periods of time. The symptoms are slower to develop, and acute period is rarely reached, and convalescence may continue for several months. - long manifestation

Describe the importance of vectors in disease transmission.

- arthropods - many pathogens hitch a ride on anthropoids such as fleas and mosquitos which act as vectors (living organisms acting as reservoirs and carrying disease agents from one host to another) - mechanical vectors - represent anthropoids passively transporting microbes on their legs and other body parts. (e.g., house flies can carry disease picked up on their feet) - anthropoids represent biological vectors - where the pathogens must multiply in the insect before it can infect another host. - teacher's def - vector is an organism that is use to transport that virus or bacteria (e.g. lyme disease)

Distinguish between endemic, epidemic, outbreak, and pandemic disease

- endemic - refers to a disease habitually present at a low level (plague) - epidemic - refers to a disease that occurs in excess of what is normally found within that population (influenza) - outbreak - a more contained epidemic - pandemic- is a worldwide epidemic

Distinguish between (a) an exogenous and an endogenous infection, (b), a primary and second infection, and (c) a local and systematic disease

- exogenous infection - is when a pathogen from the environment breaches the host external defenses and enters the host teacher's def - outside source (e.g., strept throat) - endogenous infection - is when a pathogen gains access to sterile tissue (sterile tissues can include blood, cerebrospinal fluid, going fluid, and internal organs, such as the kidneys, liver, muscles, bone, and brain are sterile) teacher's def -( e.g., e.coli invading another environment/ urinary infections in kids? - primary infection - occurs in an otherwise healthy body - secondary infection - develops with an individual that is already weakened by a primary infection * Example - During pandemic outbreak millions contracted influenza pandemic/ hundred contracted influenza as a primary infection and developed pneumonia as a secondary infection - local disease - are restricted to a single area of the body - systematic disease - are those where the focus of infectious have spread via the blood to deeper organs & systems - have to travel through circulatory system much more dangerous

Define mutualism, commensalism, and parasitism

- mutualism - is when symbiosis is beneficial to both the host and microbe * ex. lactobacillus in the vagina derive nutrients from the environment while it produces acid to prevent overgrowth of other organisms - teacher's def - relationship that we both benefit from - commensalism - a symbiosis that can also be beneficial only to microbe and the host remains unaffected - teacher's def - one benefits at no cost to the host - parasitism - is when the pathogen causes damage to the host and disease can results - teacher's def - organism compromises the host

Differentiate between signs and symptoms and how they are related to a syndrome.

- signs - is a recognizable pattern in the progress of the disease following the entry of the pathogen into the host. It represents evidence of a disease detected by an observer (physician) (e.g.,fever or bacterial cells) - symptoms- represents changed in body function sensed by the patient (e.g., sore throat and headaches) - Disease also may be characterized by a specific collection of signs and symptoms called a syndrome. (e.g., ADIS is an example where the individual exhibits over time a typical set of opportunistic infections)

Summarize the ways in which emerging and resurgent diseases are driven

- these are diseases that we haven't seen in the past, the part of why we are seeing these diseases is because we are moving into areas where humans were not present in the past - we have survival of the fittest going again because we are watching evolution and seeing adaption taking place because of the use of antibiotics Disease emergence and resurgence are driven (in decreasing rank of disease involvement) - 1. changes in land use or agriculture (deforestation and water projects) - 2. changes in human demographics (the migration of many people) - 3. poor population health ( e.g., malnutrition or poor public health infrastructure) - 4. Pathogen evolution ( pathogens developing resistance to antibiotic and anti-microbial drugs) -5. contamination of food sources and water supplies (lack of sanitation) -6. international travel (the # of people who travel can spread disease to other parts of the globe quickly) -7. failure of public health systems. ( failure of immunization programs) - 8. international trade ( global transport of produce) - 9. climate change ( global changes in weather patterns bring new disease to new latitudes and elevations)

Name and describe the activity of five enzymes that, as virulence factors, help pathogens overcome host defenses and contribute to the establishment of disease

1. Coagulase - (defensive enzyme) that coats the surface of the cells and the cluster of cells. Coagulase catalyses the conversion of plasma fibrinogen into fibrin, which then sticks to and forms a clot around the staphylococci cells. - This is done to form a blood clot that protects them from phagocytosis. Phagoctyosis (WBC'S) - engulfs pathogens 2. streptokinase (offensive fibrinolytic enzyme) - dissolves the fibrin clot and thus allows further tissue invasion by the pathogens. 3. Hyaluronidase - is sometimes called the "spreading factor" because it enhances penetration of a pathogen through the tissues. It digests hyaluronic acid, a polysaccharide that bind cells together in a tissue, into fragments. * The next two enzymes are part of cytotoxins which kills cells. 4. Leukocidins - that forms pores in and lyse those white blood cells (leukocytes) whose job it is to phagocytize and destroy the pathogens. It a white blood cell killer 5. Hemolysin - lyse red blood cells (erythrocytes) which gives the pathogens access to the iron in hemoglobin. It's a red blood cell killer

State and asses the significance of the five major period or phases that can be defined in the course of an infections disease First period of infection - incubation period

1. Incubation Period - the episode of the disease begins here and reflects the time between the entry of the microbe into the host and the appearance of first symptoms . * example - incubation period may be as short as 2-4 days for flu, 1- 2 weeks for measles, 3-6 years for leprosy

five major period or phases that can be defined in the course of an infections disease

1. Incubation period 2. Prodromal phase 3. Acute period/climax 4. Decline period 5. Period of Convalescence

Causes of Nosocoimal Infection

Causes of Nosocomial Infection: -streptoccous & staplyloccous are most common form of infection and are hugely resistant to antibiotic - gram (-) rods are e.coli and enteric bacteria that live in our gut and are increasing dramatically -pseudomonas is an opportunistic infection and were beginning to see a very high rate of antibiotic resistance - C.Diff is a big problem its also naturally our intestine its also opportunistic disease and its usually kept in check with e.coli when our system is compromised it grows in higher rate and it won't decrease and causes problems - increase in fugal infections, fungus are decomposers very few actually cause human disease but now we are becoming more susceptible now, most our secondary infections we don't have lot of things to fight off this infection

Summarize the relationship between a communicable and contagious disease.

Communicable disease - is a disease that is spread from one host to another. Certain communicable disease are described as being contagious because they are easily spread among hosts and are highly infectious. - communicable comes form individual to the next - contagious -is how easily communicable it is

Write a comparative summary of exotoxins and endotoxins, specifying the sources, chemical composition, effects, and examples of organisms producing them.

Exotoxins - are heat-sensitive protein molecules, manufactured during bacterial metabolism. They are produced by gram (+) and gram (-) bacterial cells. the extoxins are released into the host environment or, with some gram (-) bacteria injected directly into the host cell. The toxins act locally or diffuse to their site of activity and are categorized into one of the 3: the cytotoxins (kills cells), neurotoxins (interfere with nerve transmission), and enterotoxins (affect the intestinal tract by killing cells by altering membrane permeability of the epithelial cells) - gram - endotoxins - all have similar effects and are usually released upon disintegration of gram - negative cells. They are a structural component in the outer cell membrane of many gram -negative bacilli and are part of the lipopolysaccharide (LPS) complex. The lipid portion of the LPS is a toxic agent. Endotoxins do not stimulate a strong immune response in the body, nor can they be altered to prepare taxis. They function by activating a blood-clotting factor to initiate blood coagulation and by influencing the complement system. The toxins of plague bacilli are powerful. At high concentrations, they manifest their presence by certain signs sand symptoms. Usually an individual experiences and increase in body temperature, substantial body weakness and aches, and diarrhea.

Identify how portals of exit provide a way that a pathogen may use leave the host

The possible portal of exit are: -most common is coughing and sneezing, which easily spreads nasal secretions, saliva, and sputum (spit) as respiratory droplets or aerosols. - through removal of blood - by an insect bite - in the feces - in the urine - through an open lesion

-- Notes: Nosocomial infections are more common in what population?

much more common in the elderly population in individuals that are in the hospitals for long periods of time. They get secondary infections or infections because they are surrounded by too many ill people. It's a huge problem in health care today because our system is compromised and we become more susceptible to infections. Most infections are opportunistic. The # 1 opportunistic infection is urinary tract infection and its because of catheter of the elderly pop. that live in nursing home. -- there are lots of infections like MRSA -- IV & surgery -- respiratory infections