Park-Infectious Disease Flashcards
Commensalism
-the colonizing bacteria acquire nutrition and the host gets neither benefit nor harm
-commensal bacteria in a human body (normal flora) are 10x more than human cells
Mutualism
-both the microorganism and the host derive benefits from the interaction
Infectious disease
the host sustains injury or pathologic damage
infectious agents
prions, viruses, bacteria, fungi, and parasites
Viruses
obligate intracellular pathogens
What are the components of. a virus
capsid (protein coats) and genome (RNA or DNA)
How does a virus develop an envelope?
they become enclosed in a envelope that is derived from the cytoplasmic membrane of the host cell
What can viruses cause
Lysis and death of the host cell during replication
Can a virus remain in the cell without causing disease?
Yes, a virus can remain in a latent, non replicating stage, for long periods without causing disease
-ex: varicella zoster virus (chicken pox at first and shingles later)
Can viruses cause cancer?
yes, an example is human papilomavirus (HPV) which can cause cervical cancer
Bacteria are___
prokaryotic
What are shapes of bacteria?
-spherical (diplococci, staphylococci, streptococci)
-elongated (bacilli)
-helical (sprilla [spirochetes])
Spirochetes
-anaerobic (bacteria)
-borrelia burgdorferi (Lyme disease)
-treponema pallidum (syphilis)
Mycoplasma
-bacteria that is much smaller than other bacteria
-have no cell wall which makes them resistant to cell-wall inhibiting antibiotics (such as penicillins)
-mycoplasma pneumoniae (pneumonia)
Rickettsiaceae
-obligate intracellular pathogen (bacteria)
-transmitted via arthropod vectors (mites, fleas, ticks, lice)
-rickettsia rickettsii (rocky mountain spotted fever)
chlamydiaceae
-obligate intracellular pathogen (bacteria)
-transmitted via person-to-person contact
-chlamydia trachomatous (sexually transmitted and can cause conjunctivitis in newborns)
Superficial mycoses (dermatophytosis)
-fungi
-ringworm, athletes foot (tinea pedia), and jock itch (tinea cruris)
-caused by dermatophytes whose infection is limited to the cooler cutaneous surfaces
Systemic mycoses
-serious fungal infections of deep tissue (rare)
-candidiasis (yeast infection)..opportunistic infection of candida albican, which is commensal flora in the skin, mucous membranes, and gastrointestinal tract
-aspergillosis…a lethal form of pneumonia caused by aspergillus, a common mold in people with lung diseases or immunocompromised patients
What helps protect the body from systemic mycoses
-intact immune mechanisms and competition for nutrients provided by the bacterial floral normally keep colonizing fungi in check
what can lead to opportunistic infections?
a disease or an antibiotic therapy can upset the balance and allow opportunistic infections to arise
Protozoa
-unicellular animals (parasite)
-plasmodium (malaria)…vector born (mosquito)
-entamoeba histolytica (amebic dysentery, or amoebiasis)…contaminated water and food
-giardia duodenalis (giardiasis)…contaminated water and food
Helminths
-wormlike parasites
-roundworms, tapeworms, flukes
-mainly in GI
-transmission primarily occurs through the ingestion of fertilized eggs (ova) or the penetration of infectious larval stages through the skin
Parasitic arthropods
-ectoparasites…mites (scabies), chiggers, lice (head, body, pubic), and fleas
-these may serve as vectors of other infectious diseases such as the bubonic plague which was spread by fleas
prions
-misfolded protein found in infectious material
-creutzfeld-jakob disease (associated with other neurodegenerative conditions) is human version of mad cow disease
epidemiology
the study of the patterns and determinants of health with the goal of controlling disease and health problems
incidence
the number of new cases of an infectious disease that occur within a defined population (such as per 100,000 people) over an established period of time (such as monthly, yearly, etc)