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What was the estimated cost of the Cryptosporidium outbreak in Milwaukee, Wisconsin?
What was the estimated cost of the Cryptosporidium outbreak in Milwaukee, Wisconsin?
Which Cryptosporidium species is associated with human reservoirs and was first detected in 1976?
Which Cryptosporidium species is associated with human reservoirs and was first detected in 1976?
What percentage of individuals infected with Cryptosporidium sought outpatient medical care during the outbreak?
What percentage of individuals infected with Cryptosporidium sought outpatient medical care during the outbreak?
What was the average hospital stay for individuals hospitalized due to the Cryptosporidium outbreak?
What was the average hospital stay for individuals hospitalized due to the Cryptosporidium outbreak?
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In the two-year follow-up study, what percentage of death records indicated Cryptosporidium as a contributing cause was associated with AIDS?
In the two-year follow-up study, what percentage of death records indicated Cryptosporidium as a contributing cause was associated with AIDS?
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Which group of animals is NOT mentioned as a host for the protozoan?
Which group of animals is NOT mentioned as a host for the protozoan?
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What is the average incubation period for cryptosporidiosis in individuals?
What is the average incubation period for cryptosporidiosis in individuals?
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What transmission route is primarily associated with this protozoan infection?
What transmission route is primarily associated with this protozoan infection?
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What kind of food source is NOT implicated in transmission of this protozoan?
What kind of food source is NOT implicated in transmission of this protozoan?
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What percentage of drinking water samples tested showed contamination with oocysts?
What percentage of drinking water samples tested showed contamination with oocysts?
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Which group of individuals is more susceptible to severe disease due to this protozoan?
Which group of individuals is more susceptible to severe disease due to this protozoan?
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What is the diameter range of the thick-walled oocyst of the protozoan?
What is the diameter range of the thick-walled oocyst of the protozoan?
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How many oocysts are approximately needed to cause an infection?
How many oocysts are approximately needed to cause an infection?
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What was the significant issue observed at the South water treatment plant during the outbreak?
What was the significant issue observed at the South water treatment plant during the outbreak?
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Which variant of Cryptosporidium is associated with bovine and human reservoirs?
Which variant of Cryptosporidium is associated with bovine and human reservoirs?
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What was the primary cause attributed to the economic impact of the cryptosporidiosis outbreak?
What was the primary cause attributed to the economic impact of the cryptosporidiosis outbreak?
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What percentage of individuals infected with cryptosporidiosis did not seek medical care during the outbreak?
What percentage of individuals infected with cryptosporidiosis did not seek medical care during the outbreak?
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Which of the following species of Cryptosporidium is considered an uncommon cause of human infection, especially in HIV infected patients?
Which of the following species of Cryptosporidium is considered an uncommon cause of human infection, especially in HIV infected patients?
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Which of the following animals is NOT identified as a host for the protozoan?
Which of the following animals is NOT identified as a host for the protozoan?
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What is the likely average incubation period for cryptosporidiosis in adults?
What is the likely average incubation period for cryptosporidiosis in adults?
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Which method of transmission is NOT associated with this protozoan?
Which method of transmission is NOT associated with this protozoan?
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Which food item is explicitly mentioned as an implicated source of infection?
Which food item is explicitly mentioned as an implicated source of infection?
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What characteristic of the thick-walled oocyst aids in the protozoan's infection process?
What characteristic of the thick-walled oocyst aids in the protozoan's infection process?
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What percentage of individuals who were infected with this protozoan were reported to have developed severe disease symptoms?
What percentage of individuals who were infected with this protozoan were reported to have developed severe disease symptoms?
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What is a specific characteristic of the oocysts that contributes to re-infection in hosts?
What is a specific characteristic of the oocysts that contributes to re-infection in hosts?
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Which of the following groups is particularly at risk for severe disease caused by cryptosporidiosis?
Which of the following groups is particularly at risk for severe disease caused by cryptosporidiosis?
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What is the primary route through which the protozoan is transmitted?
What is the primary route through which the protozoan is transmitted?
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Which of the following food sources is recognized as a potential vehicle for transmission?
Which of the following food sources is recognized as a potential vehicle for transmission?
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Which characteristic of the protozoan's oocysts aids in re-infection?
Which characteristic of the protozoan's oocysts aids in re-infection?
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What average incubation period does cryptosporidiosis typically exhibit in children and the elderly?
What average incubation period does cryptosporidiosis typically exhibit in children and the elderly?
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Which of the following environmental sources was reported to show contamination with oocysts?
Which of the following environmental sources was reported to show contamination with oocysts?
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What is the average infectious dose of oocysts known to cause infection?
What is the average infectious dose of oocysts known to cause infection?
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What is the primary challenge in treating infections in immunocompromised individuals?
What is the primary challenge in treating infections in immunocompromised individuals?
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Which of the following is a typical diameter range for the thick-walled oocysts?
Which of the following is a typical diameter range for the thick-walled oocysts?
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How do sporozoites in the intestine contribute to the infection process after excystation?
How do sporozoites in the intestine contribute to the infection process after excystation?
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Which group of animals is most likely a host for the protozoan based on the information provided?
Which group of animals is most likely a host for the protozoan based on the information provided?
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What was a prominent factor indicated by the audits regarding individuals who contracted cryptosporidiosis?
What was a prominent factor indicated by the audits regarding individuals who contracted cryptosporidiosis?
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Which factors contributed significantly to the economic cost of the cryptosporidiosis outbreak?
Which factors contributed significantly to the economic cost of the cryptosporidiosis outbreak?
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What was the timeline of water treatment plant issues during the outbreak?
What was the timeline of water treatment plant issues during the outbreak?
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Which developmental history is correct regarding the identification of Cryptosporidium?
Which developmental history is correct regarding the identification of Cryptosporidium?
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Which species of Cryptosporidium is primarily linked with bovine reservoirs?
Which species of Cryptosporidium is primarily linked with bovine reservoirs?
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What was the duration of hospitalization for infected individuals experiencing severe symptoms?
What was the duration of hospitalization for infected individuals experiencing severe symptoms?
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In the two-year follow-up study, what percentage of death records cited cryptosporidiosis as a contributing cause?
In the two-year follow-up study, what percentage of death records cited cryptosporidiosis as a contributing cause?
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Which group of Cryptosporidium is recognized as uncommon but notable in HIV infected patients?
Which group of Cryptosporidium is recognized as uncommon but notable in HIV infected patients?
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What percentage of the population affected by the cryptosporidiosis outbreak lived outside of Milwaukee?
What percentage of the population affected by the cryptosporidiosis outbreak lived outside of Milwaukee?
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Which factor was a significant public health response during the outbreak?
Which factor was a significant public health response during the outbreak?
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Study Notes
Cryptosporidium
- Cryptosporidium was first isolated in 1907, but the first human cases were reported in 1976.
- Cryptosporidium parvum type 1 is now referred to as Cryptosporidium hominis and is associated with human reservoirs.
- Cryptosporidium parvum type 2 is now referred to as Cryptosporidium parvum and is associated with bovine and human reservoirs.
- Cryptosporidium felis, C. meleagridis, and a new cervine (deer) genotype are uncommon causes of human infection, but are seen more commonly in HIV-infected patients.
- The protozoan is found in fish, amphibians, reptiles (snakes, lizards, tortoises), wild and domesticated birds (chickens, turkeys, ducks, canaries, cockatiels), and mammals (rodents, cats, dogs, sheep, goats, pigs, deer, cows, and humans).
Cryptosporidium Outbreak (Milwaukee, 1993)
- Between March and April 1993, 403,000 people in Milwaukee, Wisconsin, contracted cryptosporidiosis.
- Two water treatment plants serving 800,000 residents and 10 other municipalities were involved.
- The South plant showed increased turbidity starting March 21st, with significantly higher levels from March 23rd to April 5th.
- A boil water order was issued on April 7th.
- The plant was temporarily shut down on April 9th.
Cryptosporidium Outbreak: Impact
- A medical record audit from the 4-month period before and after the outbreak showed 88% of infected individuals did not seek medical care.
- 11% sought out patient medical care.
- 1% were hospitalized (average stay was 8 days).
- The estimated cost of the outbreak was approximately 96.2 million, with 67% attributed to lost productivity.
- A 2-year follow-up study identified 54 death records where cryptosporidiosis was a contributing or underlying cause of death. 85% were associated with AIDS.
Transmission
- Transmission is primarily via the fecal-oral route, including contaminated drinking or recreational water, and food.
- Close contact with infected humans or other species (e.g., petting zoos) can also transmit the infection.
- Environmental contamination is common worldwide. A study showed oocysts in 27% of drinking water samples from 66 inspected treatment plants.
- Implicated food sources include raw vegetables, basil, cilantro, fresh-pressed apple cider, chicken salad, and shellfish. A 1996 CDC report linked an infected caterer changing a diaper and preparing chicken salad to an outbreak involving 50 infected people.
Infection Process
- The incubation period (IP) ranges from 2 to 14 days, with an average of 7 days.
- Children and the elderly experience a shorter IP of about 5 days.
- Cryptosporidiosis affects all ages, but the most severe cases are in immunocompromised individuals.
- Immunocompromised individuals are more susceptible to infection, harder to treat, and more likely to experience severe sequelae.
- The round, thick-walled oocyst is 4-6 µm in diameter.
- After ingestion, enzymes and bile salts trigger excystation, releasing 4 sporozoites that enter intestinal cells.
- Sporozoites mature and asexually divide, producing merozoites. Merozoites either reinvade intestinal cells or begin sexual maturation into a zygote and sporulated oocyst.
- Approximately 1 in 5 oocysts have a thin wall and help re-infect the host.
- The remaining thick-walled oocysts exit via feces into the environment.
- The mechanism of disease is unknown. As few as 30 oocysts can cause infection, with an average infectious dose of about 130 oocysts.
- Oocysts are immediately infectious after excretion.
Symptoms
- Immunologically competent individuals typically experience illness for 2–14 days, with a median duration of 1–53 days.
- The major symptom is diarrhea, with an average of 12 stools per day (less than 25 L/day).
- Oocyst excretion can continue for several months after diarrhea stops.
- Other symptoms may include nausea, fever, vomiting, and cramping.
- C. hominis infections can also cause joint pain, eye pain, recurrent headaches, dizziness, and fatigue.
Pathology
- In immunocompetent hosts, the organism is limited to the intestine and appendix.
- In immunocompromised individuals, the organism can be found in the GI tract, hepato-biliary system, and respiratory tract.
- Illness is typically self-limiting in healthy individuals, managed by oral rehydration and antidiarrheals.
- Immunocompromised hosts with CD4+ cell counts greater than 200 /mm³ usually experience an acute illness that resolves.
- CD4+ cell counts less than 100 /mm³ may experience chronic, potentially lifelong illness.
- Extra-intestinal forms are also common.
- CD4+ cell counts less than 50 /mm³ might have a life-threatening, fulminating form of cryptosporidiosis.
- In the acute phase, up to 109 oocysts may be released per day. This excretion may last for months after symptoms resolve. Three independent stool samples are recommended for diagnosis due to intermittent excretion.
Control
- Environmental control methods include improved filtration, ozonation, and ultraviolet (UV) light.
- Current chemotherapy is suboptimal. Paramomycin for a week may be used in severe cases. HAART is a better strategy for AIDS patients.
- Oocysts are resistant to chlorine, cidex, and lysol. Water treatment facilities may not protect immunocompromised people, who should utilize reverse osmosis, boiling water for a minute, or submicron filters.
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Description
Test your knowledge on the Cryptosporidium outbreak in Milwaukee, Wisconsin. This quiz covers important details such as costs, species associated with humans, and statistics on infection rates and health implications. Dive into the specifics of transmission routes and the effects on various populations.
