Final Exam

Describe how a foodborne disease outbreak is tracked.

. A good example of effective foodborne disease tracking is the outbreak caused by E. coli O157:H7 in the United States in 2006. Through culturing and molecular studies, this outbreak was linked to the consumption of contaminated packaged spinach and was quickly traced to a food-processing facility in California.

What major advantage does an oral vaccine have over a parenteral (injected) vaccine for rabies control in wild animals?

. Trials with an oral rabies vaccine administered in food "baits" of wild animals have reduced the incidence and spread of rabies in limited geographic areas.

What are the arthropod vectors and animal hosts for typhus, spotted fever rickettsiosis and ehrlichiosis?

. Typhus: Rickettsia prowazekii, transmitted by the body or head louse bite that gets contaminated with louse feces b. Spotted Fever Rickettsiosis: Rickettsia rickettsia, transmitted by dog and wood ticks c. Ehrlichiosis: Ehrlichia chaffeensis, spread by tick bites

Describe the spread of hantaviruses to humans. What are some effective measures for preventing infection by hantaviruses?

. infects rodents that can spread it, transmitted by inhalation of virus contaminated rodent excreta b. prevention: limiting mouse habitats and contact with mice and their urine

What is the primary virulence factor for Streptococcus pneumoniae?

A capsule around the strain preventing phagocytosis

What are the virulence factors associated with Staphylococcus aureus and how do they relate to the various diseases that it causes?

A virulence factor produced by S. aureus is coagulase, an enzyme that converts fibrin to fibrinogen, forming a localized clot. Clotting induced by coagulase results in the accumulation of fibrin around the bacterial cells, making it difficult for host immune cells to contact the bacteria and initiate phagocytosis. Most S. aureus strains also produce leukocidin, a protein that destroys white blood cells. Production of leukocidin in skin lesions (boils and pimples) results in host cell destruction and is one of the factors responsible for pus. Some strains of S. aureus also produce other virulence proteins including hyaluronidase, fibrinolysis, lipase, ribonuclease, and deoxyribonuclease.

Describe the sequence of steps you would take if your child received a bite (provoked or unprovoked) from a stray dog with no collar and record of rabies immunization. Present one scenario in which you were able to capture and detain the dog and another for a dog that escaped. How would these procedures differ from a situation in which the child was bitten by a dog that had a collar and rabies tag with documented, up-to-date rabies immunizations?

A. If a domestic animal, generally a dog, cat, or ferret, bites a human, especially if the bite is unprovoked, the animal should be held in quarantine for 10 days to check for signs of rabies. B. If the animal exhibits rabies symptoms, or a definitive diagnosis of its illness cannot be made after 10 days, the human should be passively immunized with rabies immune globulin (purified human antibodies to rabies virus) injected at both the site of the bite and intramuscularly. The patient should also be actively immunized with a rabies virus vaccine. C. Because of the very slow progression of rabies in humans, this combination of passive and active immunotherapy is nearly 100% effective.

What is the purpose of tertiary wastewater treatment?

Additional removal of organic matter and suspended solids, reduces the levels of inorganic nutrients

Describe three common characteristics of pathogenic mycobacteria.

All mycobacteria are acid-fast because of the waxy mycolic acid content of their cell walls. Mycobacteria are gram positive bacteria. The waxy layer of Mycobacterium cell walls resists drying and promotes survival of pathogens.

What is biochemical oxygen demand (BOD) and why is its reduction important in wastewater treatment?

Amount of dissolved oxygen consumed by microbes to completely oxidize all organic and inorganic matter in a water sample, make sure the water no longer supports microbial growth and eliminate other potentially toxic materials

How does Streptococcus pyogenes infection cause rheumatic fever?

An untreated or insufficiently treated Streptococcus pyogenes causes molecular mimicry between the streptococcal M protein and host tissue

. Distinguish between antigenic drift and antigenic shift in influenza

Antigenic drift: minor change in influenza virus antigens due to gene mutation. Antigenic shift: major change in influenza virus antigens due to gene reassortment.

Compare and contrast bacterial, viral, and fungal diseases caused by protists in their transmission, pathogenic mechanism, and treatment.

Bacterial- contaminated food or water, most disturb the gastrointestinal tract viral- vectors (mosquitoes), enter the host then slowly build-up in the liver and then when ready enter the bloodstream destroying RBCs, both chloroquine and primaquine effectively cure malaria and a newer treatment, artemisinin fungal- allergies, mycotoxins, and mycoses (infections) treated with topical and oral meds, most common antifungal treatment amphotericin B.

Why will a disease such as human rabies likely never be eliminated?

Because it originates in animals, so you would have to eliminate or vaccinate all the animals to eradicate it

Define the cause and symptoms of common colds.

Caused by rhinovirus that is transmitted by airborne droplets. 15% are caused by coronaviruses, and 10% are caused by other viruses. Symptoms: rhinitis, nasal obstruction, watery nasal discharges, and malaise.

How are sleep patterns altered in cases of African trypanosomiasis?

Causes insomnia and sleepiness

Describe pertinent clinical features and treatment protocols for chlamydia, herpes, and human papillomavirus.

Chlamydia trachomatis causes a number of sexually transmitted diseases. nongonococcal urethritis (NGU) lymphogranuloma venereum (LGV) Human papillomavirus (HPV) causes several different infections that may be asymptomatic, but some progress to genital warts. can cause cervical neoplasia, and a few progress to cervical cancers. There is an effective HPV vaccine. Herpes simplex 2 virus (HSV-2) Infections are associated primarily with anogenital region. Causes painful blisters on penis of male and cervix, vulva, or vagina of females Typically transmitted through sexual contact and most easily transmitted when active blisters are present Genital herpes are currently incurable; however, a limited number of drugs are successful in controlling the infectious blister stage. Herpes simplex 1 virus (HSV-1) infects the epithelial cells around the mouth and lips causes cold sores (fever blisters) spread via direct contact or through saliva Lesions heal without treatment in two to three weeks.

What drugs are used to treat malaria?

Chloroquine and primaquine

Why does antibiotic treatment not affect the outcome or the severity of disease with staph food poisoning?

Classified as superantigens that produce large T cell and inflammatory response

Why are hantaviruses considered a major public health problem in the United States?

Death occurs very quickly (within several days normal), BSL-4, and there is no virus specific vaccine or treatment

Other than treated water, what are the final products of wastewater treatment?

Digested sludge and disinfection

How might these end products be used?

Digested sludge: drying, incineration ;used as fertilizer or burial Disinfection: treated effluent to discharge

Contrast the disease symptoms of diphtheria and pertussis.

Diphtheria: swelling visible in the throat. a severe respiratory disease that infects children caused by Corynebacterium diphtheriae that forms irregular rods during growth. Is preventable and treatable. Spreads by airborne droplets that lead to tissue death and a pseudomembrane in the patient's throat. Pertussis: an acute, highly infectious respiratory disease that is caused by infection with Bordetella pertussis. Characterized by a recurrent, violent cough.

What type of disease is associated with Ebola? How is it spread?

Ebola hemorrhagic fever is caused by a filovirus. Transmitted via direct contact with body fluids, the major reservoir is likely bats. Spread controlled by universal precautions and use of personal protective equipment (PPE).

What are the major virulence factors of Bacillus anthracis?

Endospores (soil is natural reservoir)

Describe a scenario for contracting a Naegleria infection.

Getting water up your nose from a hot spring

Explain at least one potential reason for the high incidence of gonorrhea as compared to syphilis.

Gonorrhea is prevalent and often asymptomatic in women. Syphilis has low prevalence and exhibits very obvious symptoms.

Describe the progression of untreated gonorrhea and untreated syphilis. Do treatments produce a cure for each disease?

Gonorrhea: symptoms in females characterized by a mild vaginitis that often goes unnoticed Untreated gonorrhea can lead to pelvic inflammatory disease. symptoms in males characterized by a painful infection of the urethral canal Complications from untreated gonorrhea include damage to heart valves and joint tissues due to inflammatory reactions from immune complexes that deposit in these areas. Syphilis: often transmitted at the same time as gonorrhea; T. pallidum can be transmitted from an infected woman to the fetus during pregnancy (congenital syphilis). three stages: primary, secondary, and tertiary Roughly half of untreated patients develop tertiary syphilis, with symptoms ranging from relatively mild infections of the skin and bone to serious and even fatal infections of the cardiovascular system or central nervous system. Penicillin highly effective for primary and secondary stages Strains resistant to penicillin and quinolones respond to alternative antibiotic therapy with a single dose of the β -lactam antibiotics cefixime or ceftriaxone.

What factors are important in the emergence or reemergence of potential pathogens, such as Clostridioides difficile

Gut dysbiosis due to long-term use of antibiotics

Describe infection by Helicobacter pylori and the resulting development of an ulcer.

H. pylori colonizes the surfaces of the gastric mucosa, where it is protected from the effects of stomach acids by the gastric mucus layer. After mucosal colonization, a combination of virulence factors and host responses cause inflammation, tissue destruction, and ulceration. Pathogen products such as the cytotoxin VacA (an exotoxin), urease, and an autoimmune response triggered by LPS all contribute to localized tissue destruction and ulceration. Individuals who get H. pylori tend to have chronic infections unless they are treated with antibiotics. Treatment is simple and important, as chronic inflammation of the gastroduodenum due to untreated H. pylori infection may lead to the development of gastric cancers.

What are the major risk factors for acquiring HIV infection in the U.S. How does these differ in males and females?

HIV infection: attacks the immune system, transferred through sexual contact or blood, very deadly, men who have sex with men, heterosexual contact, injection drug use, men who have sex with men and injection drug use, other Males have more risk factors: men who have sex with men, heterosexual contact, injection drug use, men who have sex with men and injection drug use, other For females: heterosexual contact, injection drug use, other

Which symptoms of HIV/AIDS are shared by all HIV/AIDS patients?

HIV/AIDS patients are susceptible to pneumonia caused by the fungus Pneumocystis jiroveci, but infections by various molds, yeasts, protists, and bacteria are also seen. Almost all of these opportunistic pathogens are difficult to treat.

What are the primary symptoms of Lyme disease?

Headache, backache, chills, and fatigue

Why are Zoogloea ramigera important?

Helps further reduce the possibility of biological contamination

What host organ do hepatitis viruses attack? How are hepatitis A, B, and C viruses transmitted?

Hepatitis is a liver inflammation commonly caused by an infectious agent. Hepatitis A (HAV), although occasionally transmitted person to person, are more commonly transmitted by food. Infection with hepatitis B (HBV) is often called serum hepatitis because it is transmitted in blood or body fluids in contact with blood. Hepatitis C (HCV) is also transmitted parenterally. HCV produces a mild or even asymptomatic disease at first, but later on up to 85% of those infected develop chronic hepatitis, with up to 20% proceeding to chronic liver disease and cirrhosis.

What is a reassortant influenza virus and why can such viruses be so dangerous?

Highly virulent, as they tend to produce antigens to which humans have no prior exposure and thus no immunity

How do we know where the most cases are and if the numbers are going down?

Hospital statistics

Indicate the steps you would take to identify and treat infections from the smallpox virus or anthrax in a bioterror attack.

Identify the symptoms, quarantine infected, administer vaccine

Which stages of the Plasmodium life cycle occur in humans, and which in the mosquito?

In mosquito: i. Transmission by bite of mosquito ii. Maturation of gametes within mosquito iii. Fertilization iv. Growth v. Development of sporozoites vi. Release of sporozoites b. In humans: i. Transmission by bite of mosquito. Sporozoites removed from blood by liver ii. Exoerythrocytic stage: formation of schizont and merozoites iii. Infection of red blood cell iv. Erythrocytic stage: merozoites infect and reproduce in red blood cells (symptoms of malaria) v. Production of gametocytes

Identify the effect of immunization on the incidence of measles, mumps, rubella, and chicken pox.

In the United States, the incidence of measles, mumps, and rubella has decreased significantly since the implementation of the MMR vaccine.

Describe potential prevention and treatment methods for hepatitis A, B, and C viruses.

Infection with HCV or HBV can be prevented with effective vaccines. No effective vaccines are available for HCV. For those unvaccinated, the practice of precautions that prescribe a high level of vigilance and aseptic handling and containment procedures to deal with patients, body fluids, and infected waste materials will prevent infection. Most treatment of hepatitis is supportive, providing rest and time for the immune system to attack the infection and allow liver damage to be repaired. In some cases, in particular for HBV infections, some antiviral drugs are available that offer effective treatment.

How are gonorrhea and syphilis diagnosed?

Infection with N. gonorrhoeae can be diagnosed by direct observation of Gram-stained smears of a patient sample such as urethral exudates from men. The presence of gram-negative diplococci in clumps and in inclusions in neutrophils is diagnostic for the disease. In women, however, cervical smears often do not reveal the presence of the infecting organism; cultures or molecular techniques are used to establish or confirm a diagnosis of gonorrhea. x Indirect EIAs are used to detect antibodies to pathogens in body fluids, specifically Treponema pallidum (syphilis).

Discuss the possibilities for effective immunization programs for influenza and compare them to the possibilities for immunization for colds.

Influenza epidemics can be controlled by immunization. Developing an effective vaccine is complicated by the large number of existing influenza viral strains resulting from antigenic drift and antigenic shift. Through worldwide surveillance, samples of the major emerging strains of influenza virus are obtained each year before the onset of seasonal epidemics and used to prepare that year's vaccine Cold cannot be immunized against.

What is used to disinfect drinking water?

Iron, manganese

Outline the steps taken to eradicate smallpox.

Isolation, quarantine, vaccination, and surveillance

Why is E. coli used as an indicator organism in microbial analysis of water?

It can be distinguished from total coliforms with defined substrates

Why is Zika virus disease considered dangerous even though it rarely kills?

It can be transmitted from mother to fetus, leading to severe neurological problems in the developing embryo (microcephaly or pathological small head)

Think about the Covid-19 pandemic. What causes it, how does it spread, how can we stop the pandemic?

It's caused by a virus, it spreads through bodily fluids like saliva and its also airborne, we could stop it by wearing masks, getting vaccinated, social distancing, quarantining, knowing the symptoms, getting tested just in case

By using epidemiological surveillance data, how can a common-source epidemic be recognized?

Look for an increase in prevalence

Contrast the modes of transmission of the following diseases: rabies, Lyme disease, yellow fever, West Nile disease, anthrax, and plague. Which of these diseases could be virtually eliminated in humans by control of the disease vector and which could not and why?

Lyme disease is caused by infection with a spirochete, Borrelia burgdorferi, transmitted by a tick bite. The ticks that carry B. burgdorferi feed on the blood of birds, domesticated animals, various wild animals, and humans. Following a bite from an infected mosquito, the yellow fever virus replicates in lymph nodes and certain immune system cells and eventually travels to the liver. West Nile virus causes West Nile fever, a human viral disease that is transmitted through the bite of a mosquito and thus is a seasonal disease. The virus can invade the nervous system of its warm-blooded hosts. Fleas ingest Y. pestis cells in a blood meal and the bacterium multiplies in the flea's intestine. The infected flea transmits the disease to rodents or humans in the next bite. The most common form of plague in humans is bubonic plague. Cells of Y. pestis travel to the lymph nodes, where they replicate and cause swelling. The pronounced swollen lymph nodes are called buboes. The buboes become filled with Y. pestis cells, and the bacterium's capsule prevent phagocytosis and destruction by cells of the immune system. Secondary buboes form in peripheral lymph nodes, and cells eventually enter the bloodstream, causing septicemia. From soil, cells or spores of B. anthracis can become embedded in animal hair, hides, or other animal materials, or can be ingested, and from here the disease can develop, allowing B. anthracis spores to be transmitted to humans. Anthrax is primarily seen in domesticated farm animals, particularly in cattle, sheep, and goats, and is transmitted from them to humans. The rabies virus enters the body from virus-contaminated saliva through a wound from a bite or through contamination of mucous membranes. Rabies virus multiplies at the site of inoculation and travels to the central nervous system

What is the likely outcome of Listeria monocytogenes exposure in normal healthy individuals?

May lead to bacteremia and meningitis

How do the genomes of the measles virus and the German measles virus differ?

Measles often affects susceptible children as an acute, highly infectious, often epidemic disease caused by a paramyxovirus negative-strand RNA virus Virus enters the nose and throat by airborne transmission. Rubella caused by a positive-strand RNA virus of the togavirus group Disease symptoms resemble measles but are generally milder and less contagious. Routine childhood immunization is practiced in the United States

Describe the potential serious outcomes of infection by measles, mumps, rubella, and VZV viruses.

Measles: can cause serious symptoms such as ear infection, pneumonia, seizures, permanent brain damage, or death. Mumps: hearing loss, and painful swelling of the testicles or ovaries, breathing problems or meningitis, which leads to death. Rubella: Becoming infected with rubella during pregnancy can result in a miscarriage or serious birth defects. Varicella: can lead to severe skin infection, breathing problems, brain damage, or death. One who has had chickenpox can develop herpes zoster (also called shingles) later in life, which causes severe nerve pain, and hearing or vision problems, which may last for months or years.

Discuss the possibilities for effective treatment and prevention of colds.

Most antiviral drugs are ineffective against the common cold. Each cold infection induces a specific, protective immunity, but the large number of viral cold pathogens precludes complete protective immunity or vaccines.

Why are these diseases more difficult to diagnose than gonorrhea or syphilis?

Most people have no symptoms.

In the United States, where is Lyme disease most prevalent?

Northeast and upper Midwest (common habitat for deer)

How could your household water system transmit disease?

Opportunistic pathogens are found in water distribution systems, they are enriched in showerheads

What is a dimorphic fungus?

Pathogenic fungi that can be either a mold or yeast

Which populations are most susceptible to serious disease from L. monocytogenes infections?

Pregnant women and fetuses

How do primary and secondary wastewater treatment methods differ?

Primary (physical) uses physical separation methods while secondary (biological) uses digestive reactions carried out by microbes under aerobic conditions to treat wastewater

Compared with all other foodborne or waterborne pathogens, what is unique about prions?

Proteins that adopt novel conformations that inhibit normal protein function and cause degeneration of neural tissue

What is the procedure for treating a human bitten by an animal if the animal cannot be found?

Rabies is diagnosed using tissue samples looking for Negri Bodies (cytoplasmic inclusions which contain rabies virus antigens). Victim can be passively immunized with rabies immune globulin. Rabies virus vaccine also provides immunization.

What does the enzyme reverse transcriptase do and why is it a good target for anti-HIV drugs?

Reverse transcriptase is the enzyme that converts the single-stranded RNA genome of HIV into cDNA and then double-stranded DNA and is essential for viral replication. Cells lack reverse transcriptase and thus reverse transcriptase inhibitors are viral-specific. Azidothymidine (AZT) closely resembles the nucleoside thymidine but lacks the correct attachment site for the next base in a replicating nucleotide chain, resulting in termination of the growing DNA chain. AZT is thus a nucleoside reverse transcriptase inhibitor. Non Nucleoside reverse transcriptase inhibitors , such as nevirapine, inhibit the activity of reverse transcriptase in a different way by interacting with the protein and altering the conformation of the catalytic site.

Trace the treatment of water through a drinking water treatment plant from inlet to the final distribution point (faucet).

Sedimentation, coagulation and flocculation, filtration, disinfection, chlorination, storage, distribution through municipal and then domestic pipes, household water tank, faucet

Why can it be said that respiratory pathogens have exploited an effective means of transmission?

Since respiratory pathogens can be spread through inhalation of droplets, it makes it very effective in terms of spreading the pathogen, as this allows it to be transferred in a short distance thus making it very easy for respiratory pathogens to spread from person to person. Also, these pathogens can cause mild symptoms so that the person will still be able to live normally. This allows the pathogens to travel and infect more hosts than if a person was debilitated with symptoms.

What is the normal habitat of Staphylococcus aureus? How does S. aureus spread from person to person?

Staphylococci commonly infect skin and wounds and may also cause pneumonia Most staphylococcal infections result from the transfer of staphylococci in the normal flora of an infected, asymptomatic individual, to a susceptible individual. Others result from toxemia following the ingestion of contaminated food.

Which room(s) in a private dwelling are potentially the most dangerous from a microbiology perspective, and why?

The bathroom, kitchen ; because they are the most universally used by not only the residing family but guests as well

How can gastric ulcers be diagnosed? How can they be cured?

The best evidence for a causal association between H. pylori and gastric ulcers comes from antibiotic treatments for the disease. Long-term treatment with antacids helps alleviate gastric ulcer symptoms temporarily, but most patients relapse within 1 year. H. pylori infection is typically treated with the antibacterial compound metronidazole, an antibiotic such as tetracycline or amoxicillin, and bismuth-containing antacid preparation.

What was the inexpensive carbon source used in the Microbiology NOW article?

The inexpensive carbon source used was molasses.

How can a microbial inventory reveal information about the presence or absence of household pets?

The microbiome found in each home varies based on the local geography and what's around. Example: rural and farmland households harbor a greater abundance of microorganisms associated with the guts of farm animals compared to urban dwellings. The same comparison can be made with pet owners to non-pet owners.

After reading the Microbiology Now which organism is an important risk for HAIs and how was it spread in the study discussed in the article? What characteristics make this organism a potential problem?

The organism is a fungal pathogen called Candida auris. It is spread through reusable thermometers that measure temperature by the armpit. C. auris occurs even when neutrophil numbers are normal, meaning/suggesting that our innate defenses do not properly contain the pathogen. This suggests this fungal pathogen uses an efficient mechanism of phagocyte evasion.

What public health conditions allow for outbreaks of typhoid fever?

The organism is transmitted in feces contaminated water, & thus typhoid fever, like cholera, is primarily restricted to areas where sewage treatment and general sanitation are either absent or ineffective.

What are the current prevention guidelines for HIV/AIDS infection? Are they effective?

There is no effective vaccine for HIV. Preventing the spread of HIV infection requires education and avoidance of high-risk

What is unusual about the oocysts of Cryptosporidium that facilitates it transmission by a water route?

They are very thick-walled and shed in feces

How does the pathogen causing schistosomiasis differ from all other pathogens considered in this chapter?

They burrow into the skin and leave surface lesions

How is Legionellosis transmitted?

Transmitted by aerosols, not person-to-person, common in cooling towers and evaporative condensers of large AC units

Why is Mycobacterium tuberculosis a widespread respiratory pathogen?

Transmitted by airborne droplets. The primary infection hyper sensitizes the patient to the bacteria and alters the individual's response to subsequent exposures, but the chronic post-primary infection results in a gradual spread of lung lesions, as the bacteria still remain latent within the lung tissue macrophages.

Identify pathogens more commonly found in the upper respiratory tract. Identify pathogens more commonly found in the lower respiratory tract.

Upper: Staph aureus, Neisseria meningitidis, Streptococcus pyogenes, Corynebacterium diphtheria, Haemophilus influenzae, common cold virus Both: Mycoplasma pneumoniae Lower: Influenza virus, M. tuberculosis, Coccidioides immitis, Bordetella pertussis, Streptococcus pneumoniae, Pneumonia viruses, Coxiella burnetii, Chlamydophila pneumoniae

What are the advantages of further treating activated sludge by anaerobic digestion?

Used as fertilizer and in landfills, most complete method of treating sewage

What measures can be taken to decrease the current incidence of pertussis in a population?

Vaccinate soon after birth

What organism causes cholera, and what are the symptoms of the disease?

Vibrio cholerae causes severe diarrhea via enterotoxin that can lead to dehydration and death

From what source are most cases of human trichinosis contracted?

Worm infected pigs (undercooked meat pork transmits larvae)

Describe the steps necessary to prevent tetanus in an individual who has sustained a puncture wound.

a. Any serious wound should be thoroughly cleaned and the damaged tissue removed. If the vaccination status of the individual is unclear or the last tetanus booster was more than 10 years ago, revaccination is recommended. If a deep wound is severe or heavily contaminated by soil, treatment might also include administration of a tetanus antitoxin preparation.

Compare and contrast toxin production and toxemia in botulism and perfringens food poisoning.

a. Botulinum: neuro-exotoxin b. Perfringens: large number of cells can be ingested, enterotoxin is produced in the intestinal tract 6-15 hours after consumption

How might Campylobacter contamination of food production animals be controlled?

a. Campylobacter is transmitted to humans via contaminated food, most commonly in undercooked poultry or pork, raw shellfish, or occasionally in fecally contaminated water from surface sources.

Describe salmonellosis food infection.

a. Caused by eating food contaminated with salmonella or handling salmonella-infected animals b. Onset occurs 8-48 hours after ingestion c. Normally resolves in 2-5 days d. Invades phagocytes and grows as an intracellular pathogen

Describe how cholera can be prevented and how it is treated.

a. Checking for bacterial presence in stools b. Treated by oral rehydration and electrolyte replacement therapy c. Prevention: Avoid ingesting water in Cholera-endemic regions, immunization not recommended

List some dairy, meat, beverage, and vegetable food produced by microbial fermentation. What is the preservation in each case?

a. Cheese, yogurt, buttermilk: Lactococcus b. Sausage: Pediococcus, Lactobacillus, Micrococcus, Staphylococcus c. Sauerkraut: Leuconostoc, Lactobacillus

What are the three forms of anthrax, and which is most dangerous?

a. Cutaneous (skin) b. Gastrointestinal c. Pulmonary (lungs)—most dangerous

Distinguish between direct and indirect transmission of disease. Cite at least one example of each.

a. Direct host-to-host: i. Infected individual transmits a disease directly to a susceptible host without the assistance of an intermediary Ii. Ex: flu, common cold, STDs, ringworm, chicken pox b. Indirect host-to-host: i. Occurs with a facilitator (either living or nonliving agent) 1. Living agent: vector 2. Nonliving agent: fomites ex: fleas, ticks, toys, cups

Contrast the major pathogens responsible for disease outbreaks in drinking water versus recreational waters?

a. Drinking water: bacterial pathogens are most common, most notably Legionella b. Recreational water: Frequently linked to parasitic pathogens. Often transmit gastrointestinal illnesses that are of either unknown microbial origin or due to chemicals or other toxic materials

Why are meats prime vehicles for pathogenic E. coli? How can contaminated meat be rendered safe to eat?

a. E. coli O157:H7 is normally present in the intestines of healthy cattle and enters the human food chain if meat is contaminated with the animal's intestinal contents during slaughter and processing. B. Ensure that meat, especially ground beef, is cooked thoroughly, which means that it should appear gray or brown with clear juices and have attained a temperature of greater than 70° C. In general, proper food handling, water purification, and appropriate hygiene also prevent the spread of pathogenic E. coli .

What is the difference between an emerging and a reemerging infectious disease?

a. Emerging: diseases that suddenly become prevalent b. Reemerging: becomes prevalent after having been under control

Distinguish between an endemic disease, an epidemic disease, and a pandemic disease.

a. Endemic: constantly present in a population b. Epidemic: occurs in a large number of people in a population at the same time c. Pandemic: worldwide

Contrast an Entamoeba and a Naegleria infection in terms of tissues infected and symptoms.

a. Entamoeba: pathogenic protist transmitted to humans primarily through contaminated water and sometimes food; infection can be asymptomatic or lead to diarrhea and/or dysentery; if untreated, invasive cells can invade the liver and occasionally the lungs and brain b. Naegleria: free-living amoeba found in soil and water runoff that can also cause amebiasis; infections usually result from swimming in warm, soil-contaminated natural water sources; enters the human body through the nose and burrows directly into the brain, causing extensive hemorrhage and brain damage

What symptoms of giardiasis would suggest that your gastroenteritis was not due to a bacterial pathogen?

a. Explosive, foul-smelling diarrhea, intestinal cramps, nausea, weight loss, and malaise b. May exhibit no symptoms and can act as carriers

What procedures are used to ensure the safety of potable water supplies?

a. Filtration and chlorination (treatment) b. Coliform testing by MPN procedure, MF procedure, and E. coli c. IDEXX Colilert test system (coliforms turn yellow, E. coli turn blue)

How might Salmonella contamination of food production animals be contained?

a. Foods containing Salmonella but heated to at least 70° C are generally safe if consumed immediately, held at 50° C or above, or quickly refrigerated. Any foods that become contaminated by an infected food handler can support the growth of Salmonella if the food is held for a long enough period, especially if it is not kept very warm or refrigerated.

In what two forms can Bacillus cereus food poisoning manifest itself?

a. Grows in food that is cooked and left to cool slowly b. rods and spores?

. Distinguish between food infection and food poisoning.

a. Infection: microbial infection resulting from the ingestion of pathogen-contaminated food followed by growth of pathogen in the host b. Poisoning: disease that results from ingestion of foods containing preformed microbial toxins (microorganisms producing the toxins do not have to grow in the host)

What are the stages of a disease?

a. Infection: the organism invades and colonizes the host b. Incubation period: the time between infection and onset of symptoms c. Acute period: disease at its height d. Decline period: disease symptoms are subsiding e. Convalescent period: patient regains strength and returns to normal

What are the insect vector, the natural host reservoir, and the treatment for plague?

a. Insect vector: fleas b. Host reservoir: domestic and wild rodents c. Treatment: gentamicin or streptomycin

Which is more severe, a disease with a high mortality or one with a high morbidity?

a. Mortality: incidence of death in a population (more severe) b. Morbidity: refers to the incidence of disease including fatal and nonfatal diseases

Describe microbial sampling procedures for solid foods such as meat.

a. Rapid detection using E. coli O157:H7 b. Tests are molecular and immunology based c. Isolation of pathogen: treatment of food to suspend microorganisms in a homogenous solution for identification

Identify physical and chemical methods used for food preservation. How does each method limit growth of microorganisms?

a. Refrigeration: slows microbial growth rate and delays spoilage b. Heating: reduce bacterial load of a product or to sterilize it; canning (not always effective) c. Drying and dehydration: lowers the moisture content, which is critical for microbial metabolic processes; adding of sugar and salt

. Identify the vector and reservoir for West Nile virus.

a. Reservoir: 130 species of birds b. Transmitted by mosquito bites

What is a zoonotic disease? What is a disease reservoir?

a. Reservoirs are sites in which infectious agents remain viable and from which individuals can become infected i. Ex. Soil is a reservoir of Clostridium tetani b. Zoonotic disease: any disease that primarily infected animals but is occasionally transmitted to humans

What are the natural reservoirs and vectors for Plasmodium species? How can malaria be prevented or eradicated?

a. Reservoirs: humans b. Vectors: mosquitos c. Malaria can be controlled by either draining swamps and other breeding areas or by eliminating the mosquito with insecticides. Several malaria vaccines are also in development, including synthetic peptide vaccines, recombinant particle vaccines, and DNA vaccines, but thus far no highly effective and reliable malaria vaccine has emerged for use in mass vaccination programs.

How does herd immunity prevent a nonimmune individual from acquiring a disease? Give an example.

a. Resistance of a group to infection due to immunity of high proportion of the group b. If a high proportion of individuals are immune to an infection, then the whole population will be protected c. Immunized people protect non immunized people because the pathogen cannot be passed on, so the cycle of infectivity is broken

How do STEC strains of Escherichia coli differ from other pathogenic E. coli?

a. STEC: Shiga toxin producing E. coli produces verotoxin, which causes bloody diarrhea and kidney failure (E. coli O157:H7)

Identify the symptoms and mechanism of staphylococcal food poisoning.

a. Staph. Aureus can grow on common foods and produce enterotoxins that lead to gastroenteritis within a few hours of consumption

What causes SARS and how can it successfully be contained?

a. Sudden Acute Respiratory Syndrome 1. Caused by the coronavirus being spread from person to person by sneezing, coughing or by contact with fomites or feces 2. Fever occurs which causes denaturation of proteins b. Infected patients are placed on strict isolation in negative pressure rooms and health care staff have to wear respirator when working with the patients to prevent spreading of infection c. The recognition of the virus outbreak can cause international response that places travel bans to and from the endemic area to isolate the disease

Give an example of a superficial, a subcutaneous, and a systemic mycosis.

a. Superficial: Trichophyton b. Subcutaneous: Sporothrix, Fonsecaea, Cladosporium c. Systemic: histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, cryptococcosis

Differentiate between superficial, subcutaneous, and systemic mycoses.

a. Superficial: caused by dermatophytes (fungi that live on the skin) b. Subcutaneous: situations where fungi colonize deeper layers of skin tend to be more serious than superficial fungal infections c. Systemic: infected through inhalation of spores; fungal growth in internal organs of the body

Distinguish among sylvatic, bubonic, septicemic and pneumonic plague.

a. Sylvatic: i. Enzootic among rodents ii. Most common form is the bubonic plague, buboes (swollen lymph nodes) develop in the infected individual b. Pneumonic: I. Occurs when Y. pestis reaches the lungs c. Septicemic: i. Rapid spread of Y. pestis throughout the body

Why are systemic fungal pathogens called opportunistic?

a. Systemic mycoses target those of any age whose immune systems have been impaired or destroyed, for example, by HIV/AIDS. Systemic mycoses are thus diseases of opportunistic pathogens, microorganisms that cause disease only in those whose immune defenses can no longer fight them off.

Describe infection by Clostridium tetani and the effects of tetanus toxin. How does the mode of action of tetanus toxin differ from that of alpha toxin produced by C. perfringens?

a. Tetanus: Exotoxin gains access to the body through soil-contaminated wound, leads to paralysis of muscles b. Gangrene: found in soil and intestinal tract of mammals, enters deep tissue through trauma, destroys tissues by proteolysis and gas-producing clostridia

Describe differences in the transmission of botulism in adults versus infants.

a. The majority of infant botulism cases occur from toxin produced following actual infection of the infant with C. botulinum. This occurs most commonly in newborns up to about 2 months of age because they lack a well-developed intestinal microflora that can outcompete C. botulinum. Ingested C. botulinum endospores germinate in the infant's intestine, triggering growth and toxin production. b. Wound botulism can also occur from infection presumably from endospores in contaminating material introduced via a parenteral route. Wound botulism is most commonly associated with illicit injectable drug use.

Outline methods for prevention of Borrelia burgdorferi infections.

a. Tickborne disease b. Wear bug spray, cover your body

Why does epidemiologist acquire population-based data about infectious diseases?

a. To trace the spread of a disease and identify its origin b. Treatment c. Monitor the incidence (number of the diseased new cases in a given period of time) and prevalence (total number of old and new cases in a population in a given time)

How are trypanosome disease similar to malaria and how do they differ?

a. Transmitted by insect (fly) b. Parasite multiplies in blood c. Infects central nervous system and multiplies in spinal fluid

Identify the vector and reservoir for yellow fever and dengue viruses.

a. Transmitted by mosquito bites B. yellow fever: humans, monkeys, mosquitos C. dengue fever: monkeys

Describe the pathology of Campylobacter food infection. What are the major vehicles for this pathogen?

a. Transmitted to humans via contaminated food i. Raw poultry, pork, shellfish, or in surface waters b. Causes high fever, headache, malaise, nausea, abdominal cramps, and bloody stools

What precautions can be taken to prevent rickettsial infections?

a. Treatment with antibiotics b. Avoiding hosts and using insect repellents

Identify specific measure for control for Legionella pneumophila.

a. Treatment with antibiotics b. Can be prevented by improving maintenance and design of water-dependent cooling and heating systems and water delivery systems

How does one contract a case of trichomoniasis? A case of toxoplasmosis?

a. Trichomonas vaginalis: STD b. Toxoplasmosis: come into contact with a cat or undercooked meat that was infected and transmit the oocysts

Contrast the causative agents of typhoid and noro gastrointestinal disease.

a. Typhoid: Salmonella enterica serovar (typhi), bacteria b. Noro: Norwalk Agent, virus

What is potable water?

a. Used for drinking and cooking b. Undergoes extensive treatment, including filtration and chlorination

What is the difference between a disease vehicle and a disease vector?

a. Vector: living agent (mosquito, human) b. Vehicle: non-living agent (food, water, air)

What are the major means of human infectious disease transmission and give examples of each.

a. Vehicles: food, water, air b. Fomites: cups, toys, money, or door knobs c. Vectors: mosquito d. Reservoirs: soil

What characteristics make a pathogen or its products particularly useful as a biological weapon?

a. easy to produce and deliver b. safe for use by the offensive soldiers c. able to incapacitate or kill individuals under attack in a consistent and reproducible manner

Describe some of the public health activities of the U.S. Centers for Disease Control and Prevention

a. food laws lowered incidence of foodborne pathogens b. water purification reduced incidence of typhoid fever c. live agents can be killed or treated

List the major food groups as categorized by their susceptibility to spoilage.

a. fresh meat, poultry, eggs, and seafood b. fruits and vegetables c. Milk d. High-sugar foods

Compare public measures for controlling infectious diseases caused by insect vectors and human carriers.

a. insects are killed b. humans are immunized, quarantined

Identify the most likely means of acquiring cholera. Why do cholera epidemics keep occurring?

a. occurs when sewage treatment is inadequate or absent b. travelers carry the pathogen to new locations c. can be controlled by application of water treatment d. transmitted through ingestion of contaminated water

What is bioremediation and why is it needed?

dry cleaning fluids and chemical feedstocks which have been improperly disposed of and contaminates groundwater, to clear water of harmful chemicals and contaminants

What is an index case?

first case reported

Describe the infection by Neisseria meningitides and the resulting development of meningococcemia.

gram-negative, non sporulating, obligately aerobic, oxidase-positive, encapsulated diplococcus causes one type of infectious bacterial meningitis and a related infection, meningococcemia

Identify the symptoms and causes of meningitis

inflammation of the meninges membranes that line the central nervous system, especially the spinal cord and brain can be caused by viral, bacterial, fungal, or protist infections that are spread via airborne routes.

What is MRSA, and why is it a health problem?

methicillin-resistant strains of S. aureus S. aureus infections have been treated with various penicillin and cephalosporin antibiotics. Extensive use of these antibiotics for many years has selected for resistant strains that now predominate, especially in the clinical environment. Surgical patients may acquire staphylococci from healthcare personnel who are asymptomatic carriers of drug-resistant strains. As a result, appropriate antimicrobial drug therapy for S. aureus infections is a major problem in healthcare environments.

How does the physiology of C. perfringens make it suitable for growing in puncture wounds?

perfringens alpha toxin is a phospholipase that hydrolyzes the membrane phospholipids of host cells, leading to cell lysis and the typical accumulation of gas and fluids that accompanies gas gangrene.