Finals Flashcards
If cholera not promptly treated leads to
Dehydration, acidosis, hypokalemia, shock and death
Cholera characterised by
Voluminous watery stool, vomiting, hypovolemic shock and acidosis
Mode of transmission of cholera
Fecal-oral route
Source of infection of cholera
Human (primarily) and marine shellfish
Potent cholera enterotoxin is
Choleragen
Cholera is :
- Pandemic
- Epidemic
- Endemic
Epidemic
Important risk factor for gastric carcinoma and lymphoma
H.pylori ( helicobacter pylori )
Mode of transmission of h.pylori
Oral-oral or faecal-oral route
Source and reservoir of H.pylori
Human only
The ammonia produced also neutralizes gastric acidity allowing the organism to
survive causing persistent colonization which may lead to
Chronic gastritis, gastric atrophy and gastric carcinoma.
Gram -ve bacilli related to intestinal tract
Vibrio and helicobacter
Gram -ve bacilli related to respiratory tract
Heamophilus
Bordetella and
Legionella
Members of this genus is gram -ve coccobacilli
Heamophilus
1- ……. Major pathogen in haemophilus
2-……. Normal flora of the mouth and upper respiratory tract causes pneumonia or endocarditis
3-………. Causes chanroid (soft sore) —-> sexually transmitted disease manifested as an ulcer on the external genitalia
1- H.influenza
2- H.parainfluenza
3- H.ducreyi
The most virulent organism in H.influenza?
Type b
Mode of transmission of capsulated (typable) H.influenza
Droplet infection
Non-capsulated H.influenza causes non-invasive diseases such as
Otitis media, sinusitis and bronchitis
Most common cause of meningitis in children (less than 5y)
H.influenza type b
H.influenza type b cause invasive infection which are usually bacteraemic such as:
Meningitis, pneumonia & empyema (mainly in adult), acute epiglottis ( mainly in children), cellulitis, infective arthritis.
Carboxyphilic ( facultative anaerobic & required 5-10 co2)
H.influenza
G.r / H.influenza grows on chocolate agar but not on blood agar
Because is Heamophilic, requires both factors x&v
Most important member of the genus Bordetella
Bordetella pertussis
The media can be used for isolation of B.pertussis
Bordet-Gengou medium
And charcoal-blood agar
Mode of transmission for pertussis
Droplet infection
Whooping cough (pertussis) characterised by
Paroxysms (attack) of severe, spasmodic cough may be followed by vomiting, cyanosis and convulsions.
Dangerous complications of pertussis
Bronchopneumonia and acute encephalopathy
In addition to the endotoxin, B.pertussis produces an exotoxin called…….
Pertussis toxin
the most important pathogenic species in the genus Legionella.
Legionella pneumophila
The best culture medium for L. pneumophila
buffered charcoal yeast extract agar (BCYE agar)
Mode of transmission for legionella&source
Mainly environmental water sources, NO person to person transmission.
Diseases caused by L. pneumophila
1- Atypical pneumonia (Legionnaires disease j
2- Pontiac fever
Enumerate/ 4 causes of atypical pneumonia :
Legionella pneumophila
Mycoplasma pneumoniae
Viral pneumonia such as influenza
Q fever
The genus …….. (acid fast bacilli) difficult to stain with ordinary stains
Mycobacterium
….. & ……. Are the cause of TB in human
M. tuberculosis & M. bovis
G.r / M.tuberculosis can’t be stained by simple stains
Due to the high lipid content (mycolic acids) of the cell wall.
Enumerate / high conc. of lipids (mycolic acids) leads to:
- acid fast bacilli
- resistance to many antibiotics
- resistance to killing by acidic and alkaline compounds
- resistance to phagocytosis and interacellular destruction.
Mode of infection of M.tuberculosis
-droplet infection
Ingestion of milk contaminated with …….. may cause intestinal infection
M. bovis
The site of initial (primary) infection is the
Lung after inhalation of bacilli
Drug treatment for latent infection
Isoniazid (INH) or Rifampin for 6months to prevent progress of TB infection to TB disease
*** first line drugs for treatment of tuberculosis ( ٢ عددي والباقي ممكن MCQs )
***Isoniazid (INH), rifampin
Pyrazinamide and ethambutol.
*** second line drugs for treatment of tuberculosis ( ٢ عددي والباقي ممكن MCQs )
*** ciprofloxacin and ofloxacin
Paraaminosalicylic acid (PAS), ethionamide, amikacin, capreomycin, kanamycin.
Mode of transmission of M. leprae
Not known but infection requires prolonged and close contact of patients
………… is a chronic infectious disease that primarily affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes.
Leprosy
The drugs used in M. leprosy diseases
Rifampicin, clofazimine and dapsone
Hepatitis can occur in the course of several viral infections:
Cytomegalovirus (CMV), yellow fever virus, Epstein-Barr virus & rubella virus.
It is the causative agent of infectious (epidemic) hepatitis.
HAV
Hepatitis viruses manifestations (symptoms)
Fever, abdominal pain, anorexia and jaundice
It is the causative agent of serum hepatitis.
HBV
Enumerate/ (4) Population at high risk for HBV infection
- health care workers, i.v. drug users, sexual partners, infants born to HBeAg +ve mom.
- haemophiliacs, renal dialysis patients, individuals with multiple sexual partners (homo&hetero)
Symptoms in HBV tend to be
More severe & life threatening
A high rate of hepatocellular carcinoma occurs in …. …. Carriers.
Chronic HBV
??.??????? G.r / Why there is a high rate of hepatocellular carcinoma in chronic HBV/HCV
carriers…..?
-Because HBV/HCV has no encogene.
-it’s appears to be the result of persistent cellular regeneration that attempts to replace the dead hepatocytes.
- malignant transformation could be the result of insertional
mutagenesis, which could occur when the HBV genome integrates into the
hepatocyte DNA —— activation of a cellular oncogene, leading loss of growth control.
The most important laboratory test for detection of early HBV infection.
- HBsAg
- HBcAg
- HBeAg
HBsAg
It does not appear in the blood, but detectable only in nuclei of liver cells.
HBsAg
- HBcAg
- HBeAg
HBcAg
Appears in the I.P., shortly after appearance of HBsAg & is present in the prodroma and early acute disease & in certain chronic carriers.
HBsAg
-HBcAg
-HBeAg
HBeAg
presence of …….. indicates high transmissibility.
HBeAg
There is a period of several weeks when HBsAg disappeared & anti-HBs is not yet detectable and anti-HBc IgM is always positive & is used to make diagnosis.
This is the window phase
The antigen in the vaccine is…
HBsAg
Types of vaccine (HBsAg)
- plasma derived vaccine (still used)
- Recombinant vaccine (replaced ^
Persons exposed to a needle-stick injury from a patient with HBsAg positive blood. Or Newborns whose mothers are HBsAg positive. Should receive immediately:
Hepatitis B immunoglobulin (HBIG) & hepatitis B vaccine simultaneously at different sites
…… is the most prevalent blood-borne pathogen.
HCV
Mode of transmission of HCV
Mainly parenteral and via needles-stick injury (lower risk than HBV)
the most common indication for liver transplantation.
Cirrhosis resulting from chronic HCV infection
is a defective virus that replicates only in cells also infected by HBV
HDV, because is use the surface antigen of HBV (HBsAg) as its envelope.
Mode of transmission of HDV
( As HBV )Parenteral, sexual and perinatal.
Mode of transmission of HEV
Faeco-oral route
HEV it’s resembles HAV except……
It cause mortality rate in pregnant women.
It’s The causative agent of acquired immunedeficiency syndrome (AIDS)
Human immunodeficiency virus (HIV)
Mode of transmission of HIV
Parenteral, sexual and perinatal
Having HIV, does that mean having AIDS ?
No, both terms refer to the same disease, but HIV refers to the virus itself and AIDS refers to late stage of HIV infection.
Middle stage of HIV infection is
Latent stage (clinical latency)
Early stage of HIV infection is
Acute stage (acute phase viraemia)
Late stage of HIV infection is
Clinical disease (AIDS)
AIDS-related complex ( ARC) characterized by
Persistent fever
Lymphadenopathy
Fatigue,chronic diarrhea,weight loss.
Late stage HIV (AIDS), the most characteristic
Pneumocystis jiroveci pneumonia ——– Kaposi’ sarcoma.
(Complete) Late stage (AIDS), other characters are *one for each *
-viral infection Fungal infection Bacterial infection Protozoal infection Cancers
1CMV 2 cryptococcal meningitis 3 M.tuberculosis 4 toxoplasmosis 5 Non- Hodjikin lymphoma
is the most common neurologic syndrome, it occurs as a late manifestation of AIDS patients
AIDS dementia complex
AIDS dementia complex characterized by
Poor memory, inability to concentrate,apathy, psychomotor retardation and behavioral changes.
(Complete) HIV chemotherapy
1-reverse transcriptase (RT) inhibitors
2- protease inhibitors
3- Fusion inhibitors
1- nucleoside : stavudine (d4T)
Non-nucleoside : nevirapine
2 - lopinavir
3- enfovirtide (fuzeon)
(Complete) Measures to reduce transmission of HIV to fetus or newborn
- screening of pregnant mother’s from HIV
- receive AZT or nevirapine to infected mother during pregnancy
- neonates should receive the same drugs
- delivery by cesarean and no breastfeeding.
General measures ( from HIV)
Controls of blood and blood products, control of drug addiction, education of health workers, counseling HIV-infected persons,  sex education, education of the public, measures to prevent materno-fetal transmission.
-for HIV-
Vaccine production is faced with many difficulties of which:
Rapid mutation of the virus, absence of an appropriate animal model, unclear understanding of which host immune response are protective.
First common cause of common cold
Rhinoviruses
atypical pneumonia called SARS ( severe acute respiratory distress syndrome) caused by
Coronavirus
HCoV-229E :
HCoV-NL63 :
HCoV-OC43 :
HCoV-HKU1 :
SARS-CoV :
MERS-CoV :
SARS-CoV2 :
Alpha Alpha Beta Beta Beta Beta Beta
Transmission of common human coronaviruses:
Droplet infection, close personal contact
………… caused by SARS coronavirus is characterized by diffuse edema resulting in hypoxia & progressive respiratory failure.
Pneumonia
SARS is a severe atypical pneumonia characterized by
Fever, non-productive cough, dyspnea, chills, rigors, malaise &headache
Does MERS-CoV spread from person to person?
Yes, but it does not appear to spread easily from person to person; a large number of virions are likely needed to be inhaled to cause infection.
