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Questions and Answers
What is the primary vector for transmitting plague from rodents to humans?
What is the primary vector for transmitting plague from rodents to humans?
Which mechanism is crucial in preventing bacterial colonization in the alimentary tract?
Which mechanism is crucial in preventing bacterial colonization in the alimentary tract?
Which of the following is NOT a typical route of entry for microorganisms into the body?
Which of the following is NOT a typical route of entry for microorganisms into the body?
What is the most likely outcome if plague is left untreated?
What is the most likely outcome if plague is left untreated?
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Which characteristic is most descriptive of Yersinia pestis?
Which characteristic is most descriptive of Yersinia pestis?
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Which of the following factors primarily determines a host's susceptibility to infectious diseases?
Which of the following factors primarily determines a host's susceptibility to infectious diseases?
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What is the term for infections transmitted directly from animals humans?
What is the term for infections transmitted directly from animals humans?
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Which of the following processes is not directly described as a stage in the 'chain of transmission' for infectious diseases?
Which of the following processes is not directly described as a stage in the 'chain of transmission' for infectious diseases?
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Which of the following bacteria is most associated with causing bacterial pneumonias?
Which of the following bacteria is most associated with causing bacterial pneumonias?
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Under what conditions do Clostridia undergo vegetative division?
Under what conditions do Clostridia undergo vegetative division?
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Mycetomas caused by actinomyces are characterized as what type of infection?
Mycetomas caused by actinomyces are characterized as what type of infection?
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Which of the following is least likely to predispose an individual to candidiasis?
Which of the following is least likely to predispose an individual to candidiasis?
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Which of these diseases is caused by Clostridium perfringens?
Which of these diseases is caused by Clostridium perfringens?
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What characteristic defines viruses, irrespective of their nucleic acid composition?
What characteristic defines viruses, irrespective of their nucleic acid composition?
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Which geographical regions is Yellow Fever typically restricted to?
Which geographical regions is Yellow Fever typically restricted to?
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The grains discharged from the sinuses of a mycetoma infection contain what?
The grains discharged from the sinuses of a mycetoma infection contain what?
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Which of the following clinical features is most indicative of Dengue Hemorrhagic Fever (DHF) rather than uncomplicated Dengue Fever?
Which of the following clinical features is most indicative of Dengue Hemorrhagic Fever (DHF) rather than uncomplicated Dengue Fever?
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The term 'denga,' from which 'dengue' is derived, originally referred to what characteristic of the illness?
The term 'denga,' from which 'dengue' is derived, originally referred to what characteristic of the illness?
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What is the primary mechanism by which dengue virus leads to thrombocytopenia in DHF?
What is the primary mechanism by which dengue virus leads to thrombocytopenia in DHF?
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Which of the following is the most critical factor in determining the outcome of a DHF case?
Which of the following is the most critical factor in determining the outcome of a DHF case?
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What is the underlying cause of herpes zoster (shingles)?
What is the underlying cause of herpes zoster (shingles)?
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Which population is at greatest risk for severe complications from HSV-1 infections?
Which population is at greatest risk for severe complications from HSV-1 infections?
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What is the primary mode of transmission for Herpes Simplex Virus (HSV)?
What is the primary mode of transmission for Herpes Simplex Virus (HSV)?
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Which of these patient presentations would lead a physician to suspect DHF over uncomplicated Dengue Fever?
Which of these patient presentations would lead a physician to suspect DHF over uncomplicated Dengue Fever?
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Which of the following is the most accurate description of the incubation period for the rabies virus?
Which of the following is the most accurate description of the incubation period for the rabies virus?
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Which of these clinical features is most directly associated with the localization of the rabies virus in the brainstem?
Which of these clinical features is most directly associated with the localization of the rabies virus in the brainstem?
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What is the primary mechanism by which Entamoeba histolytica causes disease in humans?
What is the primary mechanism by which Entamoeba histolytica causes disease in humans?
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Which statement accurately differentiates the roles of trophozoites and cysts in the life cycle of Entamoeba histolytica?
Which statement accurately differentiates the roles of trophozoites and cysts in the life cycle of Entamoeba histolytica?
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Which of the following Plasmodium species is typically associated with the most severe and potentially fatal form of malaria?
Which of the following Plasmodium species is typically associated with the most severe and potentially fatal form of malaria?
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What is the primary vector responsible for the transmission of malaria parasites to humans?
What is the primary vector responsible for the transmission of malaria parasites to humans?
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In severe falciparum malaria, which complication directly results from the parasite's sequestration in cerebral blood vessels?
In severe falciparum malaria, which complication directly results from the parasite's sequestration in cerebral blood vessels?
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Which of the following is NOT typically associated with severe malaria caused by Plasmodium falciparum?
Which of the following is NOT typically associated with severe malaria caused by Plasmodium falciparum?
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Which form of anthrax is also known as 'wool sorters’ disease' and carries the highest fatality rate?
Which form of anthrax is also known as 'wool sorters’ disease' and carries the highest fatality rate?
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What specific characteristic of Bordetella pertussis allows it to stimulate abundant mucus production in the bronchial epithelium?
What specific characteristic of Bordetella pertussis allows it to stimulate abundant mucus production in the bronchial epithelium?
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Which of the following distinguishes streptococci from staphylococci, besides their arrangement?
Which of the following distinguishes streptococci from staphylococci, besides their arrangement?
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Which bacterial species is most frequently implicated in hospital-acquired surgical wound infections due to its antibiotic resistance?
Which bacterial species is most frequently implicated in hospital-acquired surgical wound infections due to its antibiotic resistance?
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Which of the following diseases is NOT typically associated with Staphylococcus aureus infections?
Which of the following diseases is NOT typically associated with Staphylococcus aureus infections?
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Which streptococcal group is most commonly associated with causing infections in newborns?
Which streptococcal group is most commonly associated with causing infections in newborns?
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What is a key characteristic symptom that definitively indicates a paroxysm of coughing associated with pertussis?
What is a key characteristic symptom that definitively indicates a paroxysm of coughing associated with pertussis?
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Which of the following infections is most likely to be caused by Group D streptococci (enterococci)?
Which of the following infections is most likely to be caused by Group D streptococci (enterococci)?
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Flashcards
Microorganisms
Microorganisms
Bacteria, viruses, fungi, and parasites present everywhere.
Chain of Transmission
Chain of Transmission
Process includes reservoir, route, mode, and host.
Modes of Entry
Modes of Entry
Ways pathogens enter the body (ingestion, inhalation, etc.).
Physical Barrier
Physical Barrier
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Chemical Barrier
Chemical Barrier
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Plague
Plague
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Anthrax
Anthrax
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Immune Defense Mechanisms
Immune Defense Mechanisms
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Anthrax types
Anthrax types
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Cutaneous anthrax
Cutaneous anthrax
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Pulmonary anthrax
Pulmonary anthrax
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Gastrointestinal anthrax
Gastrointestinal anthrax
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Whooping cough
Whooping cough
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Staphylococci
Staphylococci
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Staphylococcus aureus
Staphylococcus aureus
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Streptococci
Streptococci
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Streptococcus viridans
Streptococcus viridans
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Pneumococcus
Pneumococcus
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Clostridia
Clostridia
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Gas gangrene
Gas gangrene
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Mycetoma
Mycetoma
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Candidiasis
Candidiasis
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Yellow fever
Yellow fever
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Fungal infections types
Fungal infections types
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Dengue Fever Symptoms
Dengue Fever Symptoms
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Dengue Transmission
Dengue Transmission
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Dengue Hemorrhagic Fever (DHF)
Dengue Hemorrhagic Fever (DHF)
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Dengue vs. DHF
Dengue vs. DHF
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Varicella Zoster Virus
Varicella Zoster Virus
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Chickenpox Symptoms
Chickenpox Symptoms
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Herpes Simplex Virus (HSV)
Herpes Simplex Virus (HSV)
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Reactivation of VZV
Reactivation of VZV
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Rabies virus
Rabies virus
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Hydrophobia
Hydrophobia
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Amoebiasis
Amoebiasis
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Trophozoite
Trophozoite
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Cystic form
Cystic form
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Malaria
Malaria
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Plasmodium falciparum
Plasmodium falciparum
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Cerebral malaria
Cerebral malaria
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Study Notes
Infectious and Parasitic Diseases
- Microorganisms (bacteria, viruses, fungi, and parasites) are ubiquitous in soil, water, air, and on surfaces and cause many infectious diseases in humans.
Chain in Transmission of Infectious Diseases
- Reservoir of pathogen
- Route of infection
- Mode of transmission
- Susceptible host
Mode of Entry
- Microorganisms enter the body through ingestion, inoculation (parenteral), inhalation, perinatally, direct contact, or from contaminated sources (water, food, soil, or animals).
Factors Relating to Host
- Physical barriers: intact skin and mucosa prevent entry.
- Chemical barriers: mucus and stomach acid.
- Effective drainage: respiratory and gastrointestinal tracts.
- Immune defenses: phagocytic leukocytes and the immune system.
Diseases Caused by Bacteria, Spirochaetes, and Mycobacteria
- Plague is caused by Yersinia (Pasteurella) pestis.
- It's a zoonotic disease, primarily spread by rats via rat fleas or inhalation.
- Characterized by rapid progression, chills, fever, myalgia, nausea, vomiting, marked prostration, disseminated intravascular coagulation (DIC), widespread petechiae and ecchymoses, and potential gangrene (black death).
- Anthrax is caused by Bacillus anthracis.
- It's a zoonotic disease that is common in animals (cattle and sheep) but rare in humans.
- Usually an exogenous infection, contracted through contact with soil or animal products contaminated with spores.
- Three forms: cutaneous, pulmonary, and gastrointestinal. Pulmonary anthrax is most dangerous.
- Whooping cough (Pertussis) is caused by Bordetella pertussis.
- Highly communicable disease.
- Causes low-grade fever, rhinorrhoea, conjunctivitis, excess tear production.
- Characterized by paroxysms of coughing with a whooping sound; may be fatal in infants due to asphyxia.
Staphylococcal Infections
- Staphylococci are gram-positive cocci found in skin, umbilicus, nasal passages, and stool.
- Staph. aureus is the most common pathogen in staphylococcal infections.
- Staphylococcal infections include skin infections, burn infections, respiratory tract infections, bone infections (osteomyelitis), bacterial endocarditis, bacterial meningitis, sepsis, and toxic shock syndrome.
Streptococcal Infections
- Streptococci are gram-positive cocci that are more frequently associated with non-suppurative complications and autoimmune reactions..
- Group A streptococci (Streptococcus pyogenes), responsible for upper respiratory tract infections and skin infections.
- Group B streptococci (Streptococcus agalactiae), a major cause of neonatal infections.
- Group C and G, responsible for respiratory infections.
- Group D streptococci (Streptococcus faecalis, also called enterococci), can cause urinary tract infections, bacterial endocarditis, and sepsis.
- Less common streptococci, such as Streptococcus viridans and Streptococcus pneumoniae, can lead to bacterial endocarditis and pneumonia respectively.
Clostridial Diseases
- Clostridia are gram-positive, spore-forming, anaerobic microorganisms.
- Common diseases: gas gangrene (caused by C. perfringens), tetanus (caused by C. tetani), botulism (caused by C. botulinum), clostridial food poisoning (caused by C. perfringens), and necrotizing enterocolitis (caused by C. perfringens).
Diseases Caused by Fungi
- Mycetoma is a chronic, suppurative infection characterized by draining sinuses with grains (fungal or bacterial colonies).
- Two types: actinomycotic (higher bacteria) and eumycetomas (true fungi).
- Candidiasis is an opportunistic fungal infection caused most commonly by Candida albicans.
- Present as normal flora in the skin, mucous membranes, intestines, and vagina.
- Pathogenic when the host-organism balance is disturbed.
Diseases Caused by Viruses
- Viral diseases are a common cause of human illness.
- Viruses are intracellular parasites with single- or double-stranded RNA or DNA genomes.
Yellow Fever
- The oldest known viral hemorrhagic fever, restricted to Africa and South America.
- Characterized by: high fever, chills, myalgia, headache, jaundice, hepatic failure, renal failure, bleeding disorders, and hypotension.
Dengue Hemorrhagic Fever (DHF)
- Caused by virus transmitted by the mosquito Aedes aegypti.
- Two forms:
- Dengue fever ("break-bone fever")—a self-limited febrile illness affecting muscles/joints with severe back pain.
- Dengue hemorrhagic fever (DHF)—more severe and life-threatening. Characterized by vascular permeability, thrombocytopenia, plasma leakage, and potentially fatal shock.
Varicella-Zoster Virus
- Causes chickenpox (varicella) and shingles (herpes zoster).
- Chickenpox is an acute vesicular exanthem (skin rash).
- Shingles is a reactivation of dormant varicella zoster virus.
Herpes Simplex Virus
- Two types: HSV-1 (oral herpes) and HSV-2 (genital herpes).
- Characterized by vesicular lesions on skin, mouth, and genitals.
Rabies
- Fatal encephalitis caused by rabies virus.
- Transmitted through the bite of infected mammals.
- Characterized by a long incubation period, followed by progressive neurological symptoms (difficulty swallowing, painful spasms (hydrophobia), and delirium) that lead to death within weeks of infection.
Amoebiasis
- Caused by Entamoeba histolytica.
- Exists in two forms: trophozoite (active form in tissues and stool) and cyst (resistant form that survives outside the body)
Malaria
- Caused by Plasmodium species (e.g., P. falciparum, P. vivax).
- Transmitted through the bite of infected female Anopheles mosquitoes.
- Can cause severe complications including cerebral malaria, a major cause of death.
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Description
Test your knowledge on key concepts related to infectious diseases, including transmission mechanisms, host susceptibility, and specific pathogens. This quiz covers various aspects of microbiology and the factors influencing disease processes in humans.