Question

21.- Emerging infectious diseases. Examples. Factors to explain them.

22.- Epidemiology. Types of study: Descriptive – Analytical – Experimental.

23.- CDC-MMWR-Morbidity-Mortality-Notifiable infectious diseases.

24.- What is MRSA and VRSA?

25.- Leukocytosis vs Leukopenia. Plasma vs Serum.

26.- Immunity. Difference between Innate and Adaptive or Acquired.

27.- PAMPs and TLRs. Cytokines.

28.- First line of defense: Physical Factors and Chemical Factors.

29.- Second line of Defense: General Factors.

30.-Hematopoiesis.

Answer 1

21-) Emerging infectious disease are infection that have recently appeared within a population or those whose incidence or geographic range is rapidly increasing in the near future. Emerging infections can be caused by:-

• Previously unintended or unknown infectious agents
• Known agents that have spread to new geographic location or new population.
• Previously known agents whose role in specific disease has previously hone unrecoginized.
• Re-emergence of agents whose incidence of disease had significantly declined in the past, but whose incidence of disease has reappeary . This class of disease is known as re- emerging infectious disease.

Factors that have contributed to the changes are population growth, migration from rural areas to cities, international air travel, poverty , wars and destructive ecological changed due to economic development and land use.

For an emerging disease to become established at least two events have to occur-

• The infectious agent has to be introduced into a vulnerable populations and
• The agent has to have the ability to spread readily from one person person and cause disease.

22-) Epidemiology is defined as the study of the distribution and determinants of health related states or events in specified population and the application of this study to controtof health problems.

Types of Epidemiology study are:-

• Observational study
  • Descriptive study
  • Analytical study
• Experimental study
  • Randomized control trial
  • Field trials
  • Community trials

Descriptive studies

first phase of an epidemiological investigation.

Concerned with. distribution of disease or health related characteristics in human population and identifying the characteristics with which the disease in question seems to be associated.

Analytical study

• look at the entire population
• To test the hypothesis
• Used to determine whether or not a statistical association exist between a disease and a suspected factor and
• If one exist , the strength of the association

Experimental study

experimental study are of two types-

• Randomized control trial ( i.e , those involving a process of random allocation) and
• Non-randomized or Non experimental trials ( i.e., those departing from strict randomization for practical purposes , but in such a manner tha non- randomization does not seriously affect the theoretical basis of conclusion).

23-).

	morbidity	mortality
Meaning	The state of being unhealthy or diseased.	State of being mortal.
refers to	Count of ill health in a population.	Count of number of death in a population.
database	World health organisation (WHO)	The human Mortality database developed
morbidity/ mortality rate	Based on the type of disease, gender, age, etc.	Child moryrate, crude death rate, infant mortality rate, the maternal mortality rate, etc.
measured	ICU scoring system	Number of death for every thousand people.

24-) S.aureus is a leading cause of nosocomial infections, including bacteremia , surgical wound infection as well as pneumonia . Methicillin resistance was first detected in S . aureus in 1961, shortly after the agent was introduced clinically, and over the last four decades there has been a global epidemic of Methicillin resistance S .aurues ( MRSA). MARSA is usually acquired during exposure to hospital and other healthcare facilities and causes a variety of serious healthcare associated infection.

Vancomycin has been regarded as the first line drug for treatment of MRSA. Unfortunately there has been an increase in the use of this antibiotic for other infection such as pseudomembranous colitis due to clostridium difficlie and coagulase negative staphylococcal infection in hospitalized patients.

25-)

Leukocytosis	leukopenia
Leukocytosis is an elevation in the absolute WBC count( >10,000cells/micto liter	Leukopenia is a reduction in thr WBC count ( < 3500cells/ microlitre
An elevated WBC can be the normal BM response to an infectious or inflammatory process, corticosteroids , beta agonist or lithium therpy or splenectomy and is usually associated with an absolute neutrophilia.	Leukopenia can occur in response to infection ( i.e .HIV ) , inflammatory , primary BM disorders (i.e, malignancy) , autoimmune disorders, medication, environmental exposures and vitamin deficiencies
Occasionally , leukocytosis is due to a primary BM disorder with an increase in WBC production and / or delayed maturation. This may occur in the settings of hematogic malignancy	Many cases are medication induced ( i.e, chemotherapeutic or immunosuppressive drugs)
A " leukemoid reaction " is defined as an excessive WBC response usually reserved for neutrophiy ( > 50,000 / microlitre) due to a reactive cause.	Idiopathic chronic benign neutropenia may be caused by an antineutophil antibody or an inherted disorder.
Lymphocytosis is less commonly encountered and is typically associated with a atypical infection , medication use or leukemia/lymphoma.	Large granular lymphocytic leukaemia can be a cause of neutropenia , espy in patients with rheumatoid arthritis.

characteristics	serum	plasma
definition	The clear yellow fluid separated when blood is allowed to clot freely	yellowish slight alkaline fluid, in ehich blood cells float.
clotting factors	It is the watery fluid from blood without the clotting factors	It is the fluid that contains blood clotting factors
water content	The serum contains 90% water.	Plasma contains 92-95% of water
method of separation	Acquired from the process of spinning after clotting.	Acquired from the process of spinning before clotting.
density	The density of serum is 1.024g/ml	the density of plasma is 1.025g/ml.

26-) in biology , immunity is the capability of multicellular organisms to resist harmful microorganisms. Immunity invokes both specific and nonspecific.

Humans have three types of immunity - innate , adaptive and passive.

• Innate immunity:- every one is born with innate ( or natural) immunity, atype of general protection for example , the skin acts as a barrier to block germs from entering the body. And the immune system recognise when certain invaders are foreign and could be dangerous.
• Adaptive immunity:- Adaptive immunity ( or active) develops throughout our lives.we develop adaptive immunity whemn we ' re immunized against them with vaccines.
• Passive immunity:- passive immunity is " borrowed" from another source and it lasts for a short time. For example , antibodies in a monthers breast milk give a baby temporarily immunity to disease the mother has been exposed to.

27-) The innate immunity system employs germline - encoded pattern - recognition receptor (PRRs ) for the initial detection of microbes .PRRs recognize microbe - specific molecular signatures known as pathogen - associated molecular pattern ( PAMPs) and self derived molecules patterns (DAMPs)

Mammals have several distinct classes of PRRs including Toll- like receptors ( TLRs ), RIG i like receptors ( RLRs) , Nod like receptors (NLRs), and many more . Among these TLRs were first to identified, and are best characterized.

28-). First line defense ( or outside defense system) includes physical and chemical barrier thats are always ready and prepared yo defend the body from infection.These include your

• physical factors
  • Skin
  • Mucous membranes
  • Hair
  • Cilia
  • Urine
  • Defecation and vomiting
• Chemical factors
  • ​​​​​​lysosomes
  • Gastric juice
  • Saliva
  • Acidity
  • Sebum
  • Hyaluronic acid

29-) second line defense is nonspecific resistance that destroy invaders in a generalized way without targeting specific individual.

• Phagocytic cells
• Inflammation
• Fever

30-) Hematopoiesis is yhe formation of blood cellular components . All cellular blood components are derived from haematopoietic stem cells . In ahealthy adult person , approximately 10^11-12​​​​​​​ new blood cells are produced daily in order to maintain steady state level in the peripheral circulation.