Thursday, 2 January 2020

HUMAN INFECTIOUS DISEASE AND DIAGNOSTICS-ANSWER KEY



HUMAN INFECTIOUS DISEASE AND DIAGNOSTICS-ANSWER KEY
INTERNAL EXAMINATION-II (SET A&B)
SECTION-A
1. a) Hackel
2. c) monocytes  
3. d)Ehrlich
4. b)Immunogens
5. c) VR  
6. a) positive anaerobes    
7. a) Gram-negative
8. b) Pathogenicity
9. c) attenuation
10. b) bacteraemia   
11. c) entero 
12 a) V. cholerae 
13.a) falciparum 
14. c) S. dysentriae  
15. a) Bordetella 

SECTION-B
16. How can you describe the normal flora?  
A. Beneficial role: Infection resistance, Nutrient source, Stimulation of immune system and epithelial turnover: B. Disease production
Anatomical location of normal flora: Skin, Conjunctival sac, Oral cavity and Respiratory tract (Oral cavity, upper respiratory tract), Gastrointestinal tract, Urogenital tract, External auditory meatus
                       
17/22. AIDS
HIV-Retrovirus – are RNA viruses containing reverse transcriptase (a RNA directed DNA polymerase) enzyme. They are enveloped viruses with icosahedral symmetry. The genome consists of 2 copies of ss RNA with RT enzyme. They include 3 genus – Onco viruses, Lenti viruses and Spuma viruses.
AIDS; This is the end stage of the disease. There is irreversible breakdown of the immune system making the patient susceptible for any common opportunistic infections and malignancies. Respiratory infections – symptoms include – dry cough, dysponea, fever.
Ø    Gastro – intestinal tract – ginigivitis, oral thrush, dysphagia, diarrhea, abdominal pain and chronic colitis (gay bowel syndrome in homo – sexuals).
Ø    Central nervous system – lymphoma. Toxoplasmosis, Mtb, Candida, Aspergilus
Ø    Cutaneous –dermatitis, impetigo, folliculitis, Kaposi’s sarcoma. Candida and Herpes.
Ø    Paediatric AIDS
           
12. Typhoid
1. Enteric fever:
·                                 This is caused by Salmonella typhi or Sallmonella paratyphi A, B, C.
·                                 The symptoms of Salmonalla typhi are higher than Salmonella paratyphi A, B, C.
·                                 The onset is gradual with headache, malaise, loss of appetite, abdominal discomfort
·                                 Complications-bronchitis, brocho pneumonia, arthritis, abcesses, nephritis, anemia.
·                                 The Salmonella A,B and C also produces enteric fever but it is generally milder.
·                                 The infection of Salmonella paratyphi C produces septicemia.
2.Gastro Enteritis and Food Poisoning:
v    The gastroenteritis- dysentery and diarrhoea accompanied abdominal pain and fever.
v    Symptoms-headache, malaise, nausea, shivering, dehydration, hypotension, cramps 3.Bacterimia:
v    bacteria enters into the bloodstream it is dissimilated to other parts of the body
v    Complications- osteomylitis, meaningitis, abcess formation, hepatomegaly, UTI, bone marrow and kidney disorders.


13. Whooping cough.
Ø    Whooping cough (pertussis) is an infection of the respiratory systemcaused by the bacterium Bordetella pertussis (or B. pertussis).
Ø    It mainly affects babies younger than 6 months old who aren't yet protected by immunizations, and kids 11 to 18 years old whose immunity has started to fade.
Ø    Whooping cough causes severe coughing spells, which can sometimes end in a "whooping" sound when the child breathes in.

Signs & Symptoms: runny nose, sneezing, mild cough, low-grade fever


14. Dysentery.
Dysentery is an intestinal infection that causes severe diarrhea with blood. In some cases, mucus may be found in the stool. This usually lasts for 3 to 7 days.
Symptoms may include:
Ø    abdominal cramps or pain, nausea, vomiting, fever of 100.4°F (38°C) or higher, dehydration
v    Dysentery is usually spread as a result of poor hygiene.
Types of dysentery
There are two major types: Bacillary dysentery and Amebic dysentery, caused respectively by Bacteria and by Amoebas.

15. Small pox.
Etiology :Smallpox results from infection by variola virus (genus Orthopoxvirus, family Poxviridae).
https://nptel.ac.in/courses/102103039/module6/lec39/images/nm4.JPG

SECTION-C
16. Lymphoid organs and types of immunity

Primary Lymphoid Organs:

 (a) Bone marrow   (b) Thymus

Secondary Lymphoid Organs:

 (a) Spleen, (b) Lymph nodes, (c) Mucosal associated Lymphoid Tissue (MALT)

Types Of Immunity:

There are two major types of immunity: innate or natural or nonspecific and acquired or adaptive.

(A) Innate or Natural or Nonspecific Immunity (L. innatus = inborn):

Components of Acquired Immunity:

Acquired immunity has two components: humeral immunity or Antibody mediated immune system (AMIS) and cellular immunity or cell mediated immune system (CMIS).
                                               
17. Classification of microorganism
Microbial taxonomy
            Taxonomy [Greek taxis, arrangement, and nomos, law, or nemein, to distribute] is defined as the science of biological classification. In simple term, taxonomy is orderly arranging organisms under study into groups of larger units. It consists of three interrelated parts namely
1. Classification is the arrangement of organisms into groups or taxa (s., taxon) based on mutual similarity or evolutionary relatedness.
2. Nomenclature is concerned with the assignment of names to taxonomic groups in agreement with published rules.
3. Identification is the practical side of taxonomy, the process of determining that a particular isolate belongs to a recognized taxon. (So in short Identify-Naming them and classify them)

           
18. How could you explain maximum about collection & transport of clinical sample?
General instructions
Request Slips
            The request slip clearly fill in the following information.
1) Patients Name, Age, Sex, Hospital number, Date and time of collection.
2) Source of specimen.
3) Clinical details.
Blood sample collection, Urine sample collection, Ear, Nose and Eye swabs:
Biopsies, tissue scrapings etc., Sputum sample collection: Pus aspirated:
CSF sample collection:Collected sample is separated in 3 portions.
            1st portion of CSF is used for chemical analysis.
            2nd portion of CSF is used for smear analysis.
            3rd portion is used for cultural analysis.
Stool sample collection
Serological specimens

19. Can you describe in detail about staining Host pathogen interaction?       
Virulence factor
Pathogenicity-Pathogenicity denotes the ability of microorganisms to cause disease.
·                     infect a host and produce as disease is a pathogen.
Virulence-capacity of a given strain-produce disease. Attenuated - low virulence of a strain.
Virulence factors-Infectivity, Invasiveness, Toxigenicity
Infectivity: ability to overcoming, the defensive barriers of the host
Invasiveness
Toxigenicity-exotoxins (2 subunits.-Fragment B,A), endotoxins (cell wall-gram-negative bacteria).
Enzymes: virulence factor enhanced [Ex.] Hyaluronidase, Streptokinase, DNase, Coagulase.
Infecting dose: The minimum infection dose (MID) or minimum lethal dose (MLD)
Route of infection: eg. Vibrio cholerae is effective orally.
           

20. How could you explain detail about tuberculosis?
General characters: They are acid-fast, slender, rod, aerobic, non-motile, non-capsulated and non-sporing. Growth is generally slow.
Morphology: M. tuberculosis is  straight  or slightly  curved rod 1 to 4 µ long and 0.2 to 0.8 µ
·                     It may be arranged singly or in groups. It is non-motile, non-sporing and noncapsulated.
Culture Characters:It is aerobic. It grows slowly (generation time 14 to 15 hours).
·                     Colonies appear in 2 to 6 weeks. Optimum temperature is 37°C and pH is 6.4 to 7.
Pathogenesis: The basis of virulence of bacillus is unknown. It does not produce toxin. May be the various components of bacillus possess different biological activities influencing pathogenesis, allergy and immunity in disease.
Symptoms: Vague and non specific malaise, anorexia, weight loss, fever, sweats, cough. But many cases are symptomless.
·                     Site of primary infection: local lesion with enlargement of lymph nodes.
·                     Tuberculous bronchopneumonia: infection throughout the lung with discharge
·                     Caseation: Production of thick cheesy material consisting of pus cells and necrotic tissue
·                     Miliary Tuberculosis: Small tubercles found widely throughout the body
·                     Tuberculous Meningitis: Blood borne spread of infection which affects the brain
·                     Bone and Joint Tuberculosis: common form is spinal tuberculosis.

21. Describe in detail about the Nosocomial infection and malaria.
Hospital acquired infections are defined as infections developing in patients after admission to the hospital, which were neither present nor in incubation at the time of hospitalization
Source of hospital infection:
«    Endogenous origin
«    Inanimate objects
«    Exogenous origin
«    Hospital air
«    Surfaces
Mode of transmission
1. Contact route g Direct contact, Indirect contact
2. Air borne route
3. Oral route
4. Parenteral route

Malaria-Inc period – 10 – 14 days (P.falciparum, P.vivax, P.ovale); P.malariae
Prevention: Reduction in transmission, Control of mosquitoes, Prevent mosquito bite





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