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NURS 2550 FINAL EXAM
questions and answers 2025-
2026(latest update with
verified solutions)
epidemiology - answer study of disease and how it spreads incidence - answer number of new cases over a certain period of time -often expressed as rate (# new cases/population at risk) prevalence - answer number of cases within a population point prevalence - answer number of cases within a population at a given point in time period prevalence - answer number of cases within a population over a given time period (e.g., one year) endemic - answer constant presence in a population epidemic - answer increase number of cases in geographic clusters pandemic - answer more than one continent or worldwide morbidity - answer cases of illness in a given time
mortality - answer total number of deaths in a population case fatality rate - answer number of deaths among cases mixed (polymicrobial) infection - answer several pathogens at infection site secondary/opportunistic infection - answer caused by a second pathogen endogenous infection - answer patient's own flora exogenous infection - answer source outside the body local pattern of infection - answer pathogen remains confined to specific place focal pattern of infection - answer breaks loose and spreads from localized site to other tissues systemic pattern of infection - answer spreads to several sites and different body fluids patterns of disease - answer -incubation period -prodromal period -illness -period of decline -period of convalescence incubation period - answer no signs or symptoms
human types of carriers - answer -asymptomatic/subclinical (covid, gonorrhea) -incubation carriers (measles) -convalescent carriers (passing it on near end of recovery) -chronic (passing it on for a year or longer) -passive carriers (inanimate object) typhoid mary - answer A historical example (early 1900's) of a woman who was a chronic carrier of Salmonella typhi. Over the course of her infection, she was responsible for at least 10 outbreaks in New York. nosocromial infections - answer infectious diseases acquired in a health-care facility -1 in 12 develop it (1 in 8 in ICU) -proportion of HAI caused by antimicrobial-resistant organisms increasing -9% of infections -MRSA most common HAI example - answer Methicillin-resistant staphylococcus aureus (MRSA) reservoir of MRSA - answer humans (often colonizes skin and nose) transmission of MRSA - answer in hospitals via direct contact and fomites symptoms and complications of MRSA - answer -infections in wounds, insertion sites of tubing (IV, catheter)
-may spread to blood (septicemia), joints (septic arthritis), lungs (pneumonia), bones (osteomyelitis), heart (endocarditis), etc. community acquired infection (CAI) - answer infection acquired in the community/outside of the healthcare facilities example of CAI - answer measles pathogen of measles - answer virus reservoir of measles - answer humans transmission of measles - answer airborne and droplet beginning 1 day before prodromal period symptoms of measles - answer rash, fever, cough, running nose complications of measles - answer otitis media, pneumonia, encephalitis, preterm birth or low birth weight vulnerable population of measles - answer unimmunized, infants, pregnant, chronically ill herd immunity - answer The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune pathogenicity - answer disease causing virulence - answer severity of disease/ ability to damage host
-destroy parts of host cells or inhibit metabolic functions (e.g., botulism, tetanus) endotoxins - answer -lipid portion (lipopolysaccharide) of cell wall of gram neg bacteria -released when cell wall undergoes lysis -produce fever, inflammation, hemorrhage, diarrhea endotoxins and the pyrogenic response - answer 1.macrophage ingests a gram-neg bacterium
- bacterium is degraded in a vacuole, releasing endotoxins that induce the macrophage to produce cytokines IL-1 and TNF-a
- cytokines are release into bloodstream by macrophages through which they travel to the hypothalamus of the brain
- cytokines induce hypothalamus to produce prostaglandins, resetting the body's thermostat to higher temp, producing fever Factors about the host that influence disease development - answer -health status -invasive procedures and medications -nutritional status -lifestyle, occupation, hygiene, travel -decreased compliance with vaxs -medications that suppress immune function microbiome - answer -varies from person to person and body part -acquired from birth, breastmilk, food, environment -functions: microbial antagonism physical factors about the environment that increase disease - answer -climate, heat, cold, humidity, and season of the year
changing ecosystems (factors about the environment that increase disease) - answer -altered reservoirs and vectors -climate change- droughts, floods, extreme weather factors about the environment that increase disease - answer - physical -changing ecosystems -sanitary and housing conditions -food and water supplies with waste disposal -industrial land use and economic development -public health and health care infrastructure -political will to meet population needs social determinants of health - answer stronger predictors of health than behaviours such as diet, physical activity, smoking, and alcohol use organism of tuberculosis - answer mycobacterium tuberculosis -cell wall contains Ig. amt mycolic acids (lipids) and waxes, decreasing ability of macrophages to destroy (can survive inside) -eventually macrophages burst and release bacilli, immune cells contribute to formation of caseous centre and calcification of tubercle -very slow to replicate importance of tuberculosis - answer -resistant to dehydration and cell lysis -resists disinfectants, many antimicrobial drugs reservoir of tuberculosis - answer humans
mantoux skin test: five results - answer 1. active tb- person showing s/s
- had tb but now recovered following treatment
- infected but destroyed by person's immune system (given 6- month course of isoniazid to ensure death of tb bacilli)
- infected with tb, has live bacteria but not active, given 6-month course of isoniazid to ensure death of tb
- is from a country that gives tb vax BCG 50% effective multi-drug resistant tb (MDR-TB) - answer -resistant to 2 most powerful tb drugs (isoniazid and rifampicin) -3.5% of new and 18% of previously treated cases extensively drug-resistant tb (XDR-TB) - answer -8.5% of cases MDR-TB also resistant to 2 other classes of drugs ebola virus reservoir - answer fruit bat ebola fatality rate - answer 25-90% candida auris pathogen - answer first fungal infection considered threat to humans candida auris transmission - answer person-person or fomite (hard to disinfect and can live for lengthy periods) candida auris complications - answer blood stream infections candida auris fatality rates - answer 30-60%
candida auris and climate change - answer -raising temp, selects fungal clades that can reproduce at avian and mammalian basal temps -gained thermotolerance and salinity tolerance as a result on climate change on wetland ecosystem -may have been transplanted by birds across globe to humans -farming, for ex, provide interspecies transmission -eventually led to health care environments impact of climate change on pathogens and reservoirs - answer - pathogen survival -arthropod vector survival and reproduction -contamination of water -abundance of reservoir hosts impact of climate change on transmission and vulnerable hosts - answer -risk to economy (especially low and middle-income countries) -increases frequency of conflicts and food insecurity, reduces disease control + public health systems, contributes to increasing densities of infectious agents -drives economic or refugee migration examples of impact of climate change on disease - answer -tics and mosquitos survive better in warmer temps -cholera: poor access to clean water=locals infected from sewage in drinking water primary prevention of disease - answer preventing disease from occurring
zika virus (social determinants of health) - answer -more common in low income households (no screens on windows, etc.) -disability, social safety net, gender, early life, social exclusion, unemployment and job security (characteristic look and head shape) dengue fever reservoir - answer humans, monkeys -4 serotypes: DENV1 - DENV dengue fever portal of exit, transmission and portal of entry - answer -vector, mosquito, bites infected human and transmits for life -no human to human dengue fever - answer milder viral disease -rarely fatal and will get lifetime immunity from the specific serotype dengue hemorrhagic fever symptoms - answer -3-7 days after onset of dengue fever -temp decrease, irritability, persistent vomiting, sever abdominal pain, bleeding, respiratory disease, organ failure dengue hemorrhagic fever fatality - answer > 20% without treatment, 1% with medical care dengue hemorrhagic fever treatment - answer none dengue hemorrhagic fever risk factors/vulnerable hosts - answer - antibodies from previous infection -children <12 yrs
zoonotic diseases - answer exogenous disease from animal source climate change and zoonotic diseases - answer -changing habitats of vectors and reservoirs, ideal conditions for survival and breeding -animals driven closer to humans (fire) -majority of emerging diseases are from animals rabies reservoir - answer animals (raccoons, foxes, skunks, bats) rabies portal of exit - answer saliva rabies portal of entry - answer vis skin break during bite (parenteral) or contact with mucous membranes rabies pathogenesis - answer -incubation: 1-2 months. may be up to 7 yrs -multiplies locally in skin and skeletal muscle tissue -human immune system not triggered at low levels -enters peripheral nerves though neuromuscular junction to CNS -viral multiplication within brain- diverse sites throughout body inducing salivary glands prodromal symptoms of rabies - answer -fever, vomiting, fatigue furious rabies - answer -agitation, hydrophobia, delirium, hyperactivity, seizures -death within few days paralytic rabies - answer -20% of cases -paralysis from the site outward
-contact with infected feces, animals, fomites -high number of organisms (infectious dose) to cause disease salmonellosis incubation - answer 12-72 hrs -invade intestinal mucosa, multiply, occasionally spread to blood, lymph, and other organs salmonellosis symptoms - answer -moderate fever, nausea, abdominal pain, diarrhea -lasts 5-7 days -shed bacteria in stool for up to 6 mos. botulism - answer -clostridium botulinum: gram positive, anaerobic, rod shaped bacteria -spores enhance survival in soil -neurotoxin produced in an anaerobic environment -adults have competitive flora however infants at risk -one of most potent microbial toxins known salmonella is has gram - answer negative rods, over 2000 serotypes botulism food sources - answer present of veggies or meat -pressure cooking does not reach sufficient pressure or temp to kill -low-acid canning removes oxygen, ideal conditions for growth -room temp storage favours spore germination and growth -can be on improperly prepared smoked meat, cheeses, fish -produces neurotoxin in these environments
botulism incubation - answer 12-36 hrs -toxin prevents uptake of ACh at neuromuscular junction- blocks excitatory impulses- no muscle innervation botulism symptoms - answer -begins with double vision, difficulty speaking, swallowing, weakness -descending muscular paralysis and respiratory compromise -death from resp failure botulism treatment - answer give antitoxin E coli - answer Escherichia coli -gram neg, rod shaped bacteria -many harmless to normal biota most virulent E coli - answer -enterohemorrhagic E coli (EHEC) aka shiga toxin-producing E coli (STEC): most commonly 0157:H -produces shiga toxin responsible for bloody diarrhea E coli reservoir - answer -guts of ruminant animals (cattle, goats, sheep, deer, and elk) E coli incubation - answer 1-10 days E coli transmission - answer -fecal-oral, contaminated food, milk, water E coli symptoms - answer -some show minimal or no illness (carriers)
neonatal tetanus - answer -infected umbilical stump or circumcision -use of mud, ashes, cow or rat feces Mortality in neonatal Tetanus - answer >90% tetanus incubation - answer 3-21 days tetanus symptoms - answer -toxin interferes with release of neurotransmitters, blocks inhibitory impulses- unopposed muscle contraction -convulsive spasms of skeletal muscles, "lockjaw", arched back, bones may break from spasms -spasm of resp muscles tetanus fatality - answer 10%, 50-60% in developing world tetanus treatment - answer human tetanus immune globulin, muscle relaxants, sedatives, wound debridement, mechanical ventilation human causes of water contamination - answer -incorrect use of fertilizers and pesticides -leaking septic systems -improper waste disposal/landfills -chemical spills natural sources of water contamination - answer -animal fecal contaminants -excess iron, manganese, arsenic
most common pathogens in groundwater - answer -shigella -hep a -norovirus -giardia intestinalis -campylobacter -salmonella -E. coli shigella dysenteriae - answer one of 4 genus shigella -gram neg rods, nonmotile, nonencapsulated -cause dysentery (shigellosis) -few as 10 bacilli to cause disease (resistant to stomach acid) -produces exotoxin (shiga toxin) shigella dysenteriae reservoir - answer intestinal tract of humans, apes shigella dysenteriae transmission - answer -direct or indirect fecal- oral transmission (contaminated hands, chronic carrier status for > weeks) -fecally contaminated food and water -flies shigella dysenteriae risk factors - answer -malnutrition -immunocompromised -men who have sex w/ men -children -crowded conditions, poor sanitation, unsafe water supply
