Jump to content

1993 Milwaukee cryptosporidiosis outbreak: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous edit
Content deleted Content added
VisualWikitext
MollyMeta (talk | contribs)
15 edits
Added link to Milwaukee Water Quality website
Tags: Mobile edit Mobile web edit Advanced mobile edit
 
(26 intermediate revisions by 15 users not shown)
Line 1: Line 1:
{{Short description|1993 cryptosporidium protozoan outbreak in Milwaukee, Wisconsin}}
{{Short description|1993 cryptosporidium protozoan outbreak in Milwaukee, Wisconsin}}
{{Infobox outbreak
{{expert needed|Health|reason=the article previously contained several paragraphs of unsourced content|date=February 2021}}
| disease = [[Cryptosporidiosis]]
| parasite_strain = ''[[Cryptosporidium]]''
| location = [[Milwaukee, Wisconsin]]
| first_reported = April 4, 1993
| source = Contaminated water filtration plant
| confirmed_cases = 403,000
| deaths = 69
}}
The '''1993 Milwaukee cryptosporidiosis outbreak''' was a significant distribution of the ''[[Cryptosporidium]]'' [[protozoan]] in [[Milwaukee, Wisconsin]], and the largest waterborne disease outbreak in documented [[United States history]]. It is suspected that The Howard Avenue Water Purification Plant, one of two water treatment plants in Milwaukee at the time, was contaminated. It is believed that the contamination was due to an ineffective filtration process.<ref name=Corso>{{cite journal | vauthors = Corso PS, Kramer MH, Blair KA, Addiss DG, Davis JP, Haddix AC | title = Cost of illness in the 1993 waterborne Cryptosporidium outbreak, Milwaukee, Wisconsin | journal = Emerging Infectious Diseases | volume = 9 | issue = 4 | pages = 426–431 | date = April 2003 | pmid = 12702221 | pmc = 2957981 | doi = 10.3201/eid0904.020417 }}</ref> Approximately 403,000 residents were affected resulting in illness and hospitalization. Immediate repairs were made to the treatment facilities along with continued infrastructure upgrades during the 25 years since the outbreak. The total cost of the outbreak, in productivity loss and medical expenses, was $96 million.<ref name=Corso/> At least 69 people died as a result of the outbreak.<ref name=Corso/>
The '''1993 Milwaukee cryptosporidiosis outbreak''' was a significant distribution of the ''[[Cryptosporidium]]'' [[protozoan]] in [[Milwaukee, Wisconsin]], and the largest waterborne disease outbreak in documented [[United States history]]. It is suspected that The Howard Avenue Water Purification Plant, one of two water treatment plants in Milwaukee at the time, was contaminated. It is believed that the contamination was due to an ineffective filtration process.<ref name=Corso>{{cite journal | vauthors = Corso PS, Kramer MH, Blair KA, Addiss DG, Davis JP, Haddix AC | title = Cost of illness in the 1993 waterborne Cryptosporidium outbreak, Milwaukee, Wisconsin | journal = Emerging Infectious Diseases | volume = 9 | issue = 4 | pages = 426–431 | date = April 2003 | pmid = 12702221 | pmc = 2957981 | doi = 10.3201/eid0904.020417 }}</ref> Approximately 403,000 residents were affected resulting in illness and hospitalization. Immediate repairs were made to the treatment facilities along with continued infrastructure upgrades during the 25 years since the outbreak. The total cost of the outbreak, in productivity loss and medical expenses, was $96 million.<ref name=Corso/> At least 69 people died as a result of the outbreak.<ref name=Corso/>
The city of Milwaukee has spent upwards to $510 million in repairs, upgrades, and outreach to citizens.
The city of Milwaukee has spent upwards to $510 million in repairs, upgrades, and outreach to citizens.


== Epidemiology ==
== Epidemiology ==
''[[Cryptosporidium]]'' is a [[chlorine]]-resistant [[gut microbiota|enteric pathogen]] that causes a gastrointestinal illness ([[cryptosporidiosis]]) with symptoms such as [[diarrhea]]. Enteric pathogens are bacteria that humans ingest, typically through contaminated food or water.<ref>Division of Foodborne, Waterborne, and Environmental Diseases (DFWED) Home. (2023). ''Enteric Diseases Epidemiology Branch.'' Washington, D.C.: Centers for Disease Control and Prevention.</ref> Since ''Cryptosporidium'' is a coccidian parasite, it has oocysts.<ref name=":0">Centers for Disease Control and Prevention. (2023). ''Cryptosporidiosis''. Retrieved from DPDx - Laboratory Identification of Parasites of Public Health Concern: <nowiki>https://www.cdc.gov/dpdx/cryptosporidiosis/index.html</nowiki></ref> An [[oocyst]] is a period in the life cycle of a coccidian parasite. The oocysts in ''[[Cryptosporidium]]'' are the transmissible stage for cryptosporidiosis.<ref name=":0" /><ref>Centers for Disease Control and Prevention. (2023). ''Parasites Glossary''. Retrieved from Parasites: <nowiki>https://www.cdc.gov/parasites/glossary.html#oocyst</nowiki></ref>
''[[Cryptosporidium]]'' are a [[chlorine]]-resistant [[gut microbiota|enteric pathogen]]s that cause gastrointestinal illness ([[cryptosporidiosis]]) with symptoms such as [[diarrhea]]. Other symptoms include stomach cramps, dehydration, nausea, vomiting, fever, or weight loss.<ref name=":3" /> Symptoms can be more severe for people who are immunocompromised, for whom diarrhea can lead to death.<ref name=":0" /> [[Enteric pathogen]]s are microorganisms that humans ingest, typically through contaminated food or water.<ref>Division of Foodborne, Waterborne, and Environmental Diseases (DFWED) Home. (2023). ''Enteric Diseases Epidemiology Branch.'' Washington, D.C.: Centers for Disease Control and Prevention.</ref> Since ''Cryptosporidium'' is a coccidian [[Parasitic plant|parasite]], it has oocysts.<ref name=":0">Centers for Disease Control and Prevention. (2023). ''Cryptosporidiosis''. Retrieved from DPDx – Laboratory Identification of Parasites of Public Health Concern: https://www.cdc.gov/dpdx/cryptosporidiosis/index.html {{Webarchive|url=https://web.archive.org/web/20191107194205/https://www.cdc.gov/dpdx/cryptosporidiosis/index.html |date=2019-11-07 }}</ref> An [[oocyst]] is a period in the life cycle of a coccidian parasite. The oocysts in ''[[Cryptosporidium]]'' are the transmissible stage for cryptosporidiosis.<ref name=":0" /><ref name=":3">Centers for Disease Control and Prevention. (2023). ''Parasites Glossary''. Retrieved from Parasites: https://www.cdc.gov/parasites/glossary.html#oocyst {{Webarchive|url=https://web.archive.org/web/20231005064925/https://www.cdc.gov/parasites/glossary.html#oocyst |date=2023-10-05 }}</ref>


Most reports do not specify the species of ''Cryptosporidium'' involved in the outbreak. Several species cause cryptosporidiosis in humans, with most caused by ''[[Cryptosporidium parvum]]'' and ''[[Cryptosporidium hominis]]''.<ref name="MORGAN-RYAN">{{cite journal |last1=MORGAN-RYAN |first1=UNA M. |last2=FALL |first2=ABBIE |last3=WARD |first3=LUCY A. |last4=HIJJAWI |first4=NAWAL |last5=SULAIMAN |first5=IRSHAD |last6=PAYER |first6=RONALD |last7=THOMPSON |first7=R. C. ANDREW |last8=OLSON |first8=M. |last9=LAL |first9=ALTAF |last10=LIHUA |first10=XIAO |title=Cryptosporidium hominis n. sp. (Apicomplexa: Cryptosporidiidae) from Homo sapiens |journal=Journal of Eukaryotic Microbiology |date=November–December 2002 |volume=49 |issue=6 |pages=433–440 |doi=10.1111/j.1550-7408.2002.tb00224.x |pmid=12503676 |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1550-7408.2002.tb00224.x |access-date=25 June 2024 |language=en |issn=1550-7408 |oclc=4630522305 |archive-date=25 June 2024 |archive-url=https://web.archive.org/web/20240625153537/https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1550-7408.2002.tb00224.x |url-status=live }}</ref> However adding to the confusion, these two species were only split from each other in 2002.<ref name="MORGAN-RYAN" /> In 2003, [[Phaedra S. Corso]] ''et al.'' imply without evidence that it was ''C. parvum''.<ref name=Corso/> In 2001, [[Alicia C. McDonald]] ''et al.'' clearly state that ''C. parvum'' is the cause,<ref name="McDonald">{{cite journal |last1=McDonald |first1=Alicia C. |last2=Mac Kenzie |first2=William R. |last3=Addiss |first3=David G. |last4=Gradus |first4=M. Stephen |last5=Linke |first5=George |last6=Zembrowski |first6=Elizabeth |last7=Hurd |first7=Margaret R. |last8=Arrowood |first8=Michael J. |last9=Lammie |first9=Patrick J. |last10=Priest |first10=Jeffrey W. |title=Cryptosporidium parvum–Specific Antibody Responses among Children Residing in Milwaukee during the 1993 Waterborne Outbreak |journal=The Journal of Infectious Diseases |date=1 May 2001 |volume=183 |issue=9 |pages=1373–1379 |doi=10.1086/319862 |pmid=11294669 |url=https://academic.oup.com/jid/article/183/9/1373/931377 |access-date=25 June 2024 |language=en |issn=1537-6613 |oclc=118846463 |archive-date=20 January 2022 |archive-url=https://web.archive.org/web/20220120045545/https://academic.oup.com/jid/article/183/9/1373/931377 |url-status=live }}</ref> but the 1994 source they cite does not specify the species.<ref name=":1"/> McDonald ''et al.'' do find positive results testing blood samples with [[antigen]]s derived from ''C. parvum'',<ref name="McDonald" /> but a 2018 paper from Sumeeta Khurana and Preeti Chaudhary indicate that antigen tests are not species-specific and that [[molecular methods]] are needed to differentiate other species.<ref name="Khurana">{{cite journal |last1=Khurana |first1=Sumeeta |last2=Chaudhary |first2=Preeti |title=Laboratory diagnosis of cryptosporidiosis |journal=Tropical Parasitology |date=January–June 2018 |volume=8 |issue=1 |pages=2–7 |doi=10.4103/tp.TP_34_17 |doi-access=free |pmid=29930899 |language=en |issn=2229-5070 |pmc=5991046 |oclc=7704802362 }}</ref> A 2003 study by [[Ling Zhou]] ''et al.'' specifically addresses these issues and clearly identifies the pathogen in this outbreak as ''C. hominis''.<ref name="Zhou">{{cite journal |last1=Zhou |first1=Ling |last2=Singh |first2=Ajaib |last3=Jiang |first3=Jianlin |last4=Xiao |first4=Lihua |title=Molecular Surveillance of Cryptosporidium spp. in Raw Wastewater in Milwaukee: Implications for Understanding Outbreak Occurrence and Transmission Dynamics |journal=Journal of Clinical Microbiology |date=1 November 2003 |volume=41 |issue=11 |pages=5254–5257 |doi=10.1128/jcm.41.11.5254-5257.2003 |pmid=14605176 |pmc=262506 |language=en |issn=0095-1137 |oclc=9173124979 }}</ref>
⚫
== History ==
⚫
On April 4, 1993 Pharmacist Jeff Langer contacted a local television station after the Milwaukee Health Department didn’t respond to his calls regarding substantial increase in gastrointestinal complaints. Sunday evening, April 4, the station came out to interview Jeff Langer regarding the substantial increase in requests for anti-diarrhea medications. Following that television interview, April 5, 1993, Milwaukee Health Department received additional reports of [[Gastrointestinal disease|gastrointestinal illness]] at their local hospitals and calls of complaints related to reduced water-quality aesthetic. Water aesthetics include taste, color, odor, hardness/softness, and turbidity. They are considered a secondary standard under the EPA National Primary Drinking Water Regulations (NPDWR). Although these drinking aesthetics are under the EPA NPDWR, they are not federally enforced but are standard regulations that states may choose to adopt and enforce themselves. In the spring of 1993, turbidity was the main complaint. This was corroborated by Milwaukee Water Works records of Maximal Turbidity for both water treatment plants from March through April 1993.<ref name=":1" />


⚫
== History ==
Public health officials suspected recent illness to be due to water consumption. To verify suspicions, both the water treatment plants complied with data 30 days prior to the incident. The only findings were that turbidity was slightly increased but still below federally recommended levels. At the same time, hospitals did not routinely screen for ''Cryptosporidium,'' but because patients were all experiencing similar symptoms, hospitals were asked to test for ''Cryptosporidium''.{{citation needed|date=June 2021}}
⚫
On April 4, 1993, pharmacist Jeff Langer contacted a local television station after the Milwaukee Health Department did not respond to his calls regarding substantial increase in gastrointestinal complaints. Sunday evening, April 4, the station came out to interview Jeff Langer regarding the substantial increase in requests for anti-diarrhea medications. Following that television interview, April 5, 1993, Milwaukee Health Department received additional reports of [[Gastrointestinal disease|gastrointestinal illness]] at their local hospitals and calls of complaints related to reduced water-quality aesthetic. Water aesthetics include taste, color, odor, hardness/softness, and turbidity. They are considered a secondary standard under the EPA [[National Primary Drinking Water Regulations]] (NPDWR). Although these drinking aesthetics are under the [[EPA]] NPDWR, they are not federally enforced but are standard regulations that states may choose to adopt and enforce themselves. In the spring of 1993, [[turbidity]] was the main complaint. This was corroborated by Milwaukee Water Works records of Maximal Turbidity for both water treatment plants from March through April 1993.<ref name=":1" />

Independent tests were run through the Milwaukee Public Health Laboratory, to test stool samples for ''Cryptosporidium.'' On April 7, two days after initial reports, [[Mayor of Milwaukee|Mayor]] [[John Norquist]] issued a ten-day [[Boil-water advisory|boil order]] for resident to [[Boiling|boil]] their drinking water, though it still left residents vulnerable to ''Cryptosporidium'' through bathing, showering, and washing hands or clothes. The Milwaukee Health Department developed a method to survey local pharmacies and hospitals regularly on purchases of anti-diarrheal products.


== Causes ==
== Causes ==
The root cause of epidemic was never officially identified; however, it was most likely the result of human error at the Howard Avenue Water Treatment Plant. Initially it was suspected to be caused by the cattle genotype due to runoff from pastures.<ref name=":1">{{cite journal | vauthors = Mac Kenzie WR, Hoxie NJ, Proctor ME, Gradus MS, Blair KA, Peterson DE, Kazmierczak JJ, Addiss DG, Fox KR, Rose JB | display-authors = 6 | title = A massive outbreak in Milwaukee of cryptosporidium infection transmitted through the public water supply | journal = The New England Journal of Medicine | volume = 331 | issue = 3 | pages = 161–167 | date = July 1994 | pmid = 7818640 | doi = 10.1056/nejm199407213310304 | doi-access = free }}</ref> It was also thought that melting ice and snowmelt carrying ''Cryptosporidium'' may have entered the water treatment plants through [[Lake Michigan]].<ref>{{cite book| vauthors = Botkin DB, Keller EA |title=Environmental Science: Earth as a Living Planet|year=2005|isbn=978-0-471-48816-3|edition=5th|pages=441 }}</ref> MacKenzie et al. and the CDC showed that this outbreak was caused by ''Cryptosporidium'' [[oocysts]] that passed through the filtration system of one of the city's water-treatment plants, arising from a sewage treatment plant's outlet two miles upstream in Lake Michigan. This ultimately led to the death of Rich Evans. This abnormal condition at the water purification plant lasted from March 23 through April 8, after which, the plant was shut down. Over the span of approximately two weeks, 403,000<ref name="Hoxie">{{cite journal | vauthors = Hoxie NJ, Davis JP, Vergeront JM, Nashold RD, Blair KA | title = Cryptosporidiosis-associated mortality following a massive waterborne outbreak in Milwaukee, Wisconsin | journal = American Journal of Public Health | volume = 87 | issue = 12 | pages = 2032–2035 | date = December 1997 | pmid = 9431298 | pmc = 1381251 | doi = 10.2105/ajph.87.12.2032 }}</ref> of an estimated 1.61 million residents in the [[Milwaukee metropolitan area|Milwaukee area]] (of which 880,000 were served by the malfunctioning treatment plant) became ill with the stomach [[cramps]], [[fever]], [[diarrhea]] and [[dehydration]] caused by the pathogen.<ref name="Hoxie" /> After the outbreak, cryptosporidiosis antibody rates among Milwaukee children reached 80%, compared to only 10% prior to the outbreak.<ref>{{cite news |title=Cryptosporidium in Milwaukee's water supply caused widespread illness |url=https://www.healio.com/news/infectious-disease/20120225/i-cryptosporidium-i-in-milwaukee-s-water-supply-caused-widespread-illness |access-date=22 February 2021 |work=Infectious Disease News |issue=September 2007 |publisher=Healio |date=September 2007}}</ref> Deaths have been attributed to this outbreak, mostly among the elderly and [[Immunosuppression|immunocompromised]] people, such as people with [[AIDS]].<ref name="Corso" />
The root cause of the [[epidemic]] was never officially identified; however, it was most likely the result of human error at the Howard Avenue Water Treatment Plant. Initially it was suspected to be caused by runoff from upstream cattle pastures.<ref name=":1">{{Cite journal|url=http://www.nejm.org/doi/abs/10.1056/NEJM199407213310304|title=A Massive Outbreak in Milwaukee of Cryptosporidium Infection Transmitted through the Public Water Supply|first1=William R.|last1=Mac Kenzie|first2=Neil J.|last2=Hoxie|first3=Mary E.|last3=Proctor|first4=M. Stephen|last4=Gradus|first5=Kathleen A.|last5=Blair|first6=Dan E.|last6=Peterson|first7=James J.|last7=Kazmierczak|first8=David G.|last8=Addiss|first9=Kim R.|last9=Fox|first10=Joan B.|last10=Rose|first11=Jeffrey P.|last11=Davis|date=July 21, 1994|journal=New England Journal of Medicine|volume=331|issue=3|pages=161–167|via=CrossRef|doi=10.1056/NEJM199407213310304|pmid=7818640 }}</ref> It was also thought that melting ice and snowmelt carrying ''Cryptosporidium'' may have entered the water treatment plants through [[Lake Michigan]].<ref>{{cite book| vauthors = Botkin DB, Keller EA |title=Environmental Science: Earth as a Living Planet|year=2005|isbn=978-0-471-48816-3|edition=5th|pages=441 |publisher=Wiley }}</ref>


MacKenzie et al. and the CDC showed that this outbreak was caused by ''Cryptosporidium'' [[oocysts]] that passed through the filtration system of one of the city's water-treatment plants, arising from a sewage treatment plant's outlet two miles upstream in Lake Michigan. This abnormal condition at the water purification plant lasted from March 23 through April 8, after which, the plant was shut down. Over the span of approximately two weeks, 403,000<ref name="Hoxie">{{cite journal | vauthors = Hoxie NJ, Davis JP, Vergeront JM, Nashold RD, Blair KA | title = Cryptosporidiosis-associated mortality following a massive waterborne outbreak in Milwaukee, Wisconsin | journal = American Journal of Public Health | volume = 87 | issue = 12 | pages = 2032–2035 | date = December 1997 | pmid = 9431298 | pmc = 1381251 | doi = 10.2105/ajph.87.12.2032 }}</ref> of an estimated 1.61 million residents in the [[Milwaukee metropolitan area|Milwaukee area]] (of which 880,000 were served by the malfunctioning treatment plant) became ill with the stomach [[cramps]], [[fever]], [[diarrhea]] and [[dehydration]] caused by the pathogen.<ref name="Hoxie" /> After the outbreak, cryptosporidiosis antibody rates among Milwaukee children reached 80%, compared to only 10% prior to the outbreak.<ref>{{cite news |title=Cryptosporidium in Milwaukee's water supply caused widespread illness |url=https://www.healio.com/news/infectious-disease/20120225/i-cryptosporidium-i-in-milwaukee-s-water-supply-caused-widespread-illness |access-date=22 February 2021 |work=Infectious Disease News |issue=September 2007 |publisher=Healio |date=September 2007 |archive-date=21 February 2021 |archive-url=https://web.archive.org/web/20210221093625/https://www.healio.com/news/infectious-disease/20120225/i-cryptosporidium-i-in-milwaukee-s-water-supply-caused-widespread-illness |url-status=live }}</ref> Deaths have been attributed to this outbreak, mostly among the elderly and [[Immunosuppression|immunocompromised]] people, such as people with [[AIDS]].<ref name="Corso" />
⚫
== Social Impact ==
⚫
Reports of gastrointestinal illness began in April of 1993, however, studies occurring after the outbreak confirmed that there were echoes of the epidemic beyond initial contamination as the population contracted the illness through secondary transmission.<ref>{{Cite journal |last=Osewe, P.; Addiss, D.G.; Blair, K.A.; Hightower, A.; Kamb, M. L.; Davis, J.P. |first= |date=1996 |title=Cryptosporidiosis in Wisconsin: A case-control study of post-outbreak transmission |journal=Cambridge University Press |pages=297-304}}</ref><ref>{{Cite journal |last=Kenzie, Mac; Schell, L.; Blair; Addiss; Peterson; Hoxie; Kazmierczak; Davis |date=1995 |title=Massive Outbreak of Waterborne Cryptosporidium Infection in Milwaukee, Wisconsin: Recurrence of Illness and Risk of Secondary Transmission |journal=Infectious Diseases Society of America |pages=57-62}}</ref> This resulted in negative public sentiment toward Milwaukee Water Works. Carrie Lewis, superintendent of Milwaukee water works in 2015, explained that "people had been hurt, they felt let down by their drinking water and it took a  long time for them to believe that we knew what we were doing again,’<ref name=":2">Lewis, C. (2015, January 9). Superintendent of Milwaukee Water Works. (M. Gonzalez, & B. Gonzalez, Interviewers)</ref> It took ten years for Milwaukee citizens to begin to trust the public water supply again with the help of frequent community outreach by the utility.<ref name=":2" />


⚫
== Social impact ==
⚫
== Current Treatment in Milwaukee ==
⚫
Reports of gastrointestinal illness began in April 1993; however, studies occurring after the outbreak confirmed that there were echoes of the epidemic beyond initial contamination as the population contracted the illness through secondary transmission.<ref name=":1"/> This resulted in negative public sentiment toward Milwaukee Water Works. Carrie Lewis, superintendent of Milwaukee water works in 2015, explained that "people had been hurt, they felt let down by their drinking water and it took a long time for them to believe that we knew what we were doing again,"<ref name=":2">Lewis, C. (2015, January 9). Superintendent of Milwaukee Water Works. (M. Gonzalez, & B. Gonzalez, Interviewers)</ref> It took ten years for Milwaukee citizens to begin to trust the public water supply again with the help of frequent community outreach by the utility.<ref name=":2" />
Currently, Milwaukee consistently scores as one of the highest drinking water qualities in the state. This is due to over $417 million invested in water treatment and monitoring improvements since the outbreak.<ref>Ceraso, M. (2013). ''20 years after fatal outbreak, Milwaukee leads on water testing.'' Wisconsin Water Watch.</ref> Improvements in treatment include:<ref>Milwaukee Public Water Works. (2023). ''FAQs - Water Quality and Public Health - Water Treatment Process''. Retrieved from City of Milwaukee: <nowiki>https://city.milwaukee.gov/water/customer/FAQs/qualityandhealth/Water-treatment-process.htm</nowiki></ref>


⚫
== Current treatment in Milwaukee ==
* Activated charcoal filtration (Actiflo Carb) removes certain drugs, disinfectants, antibiotics
Currently, Milwaukee consistently scores as one of the highest drinking water qualities in the state.<ref name=":4">City of Milwaukee. (2022). ''Water Quality''. Retrieved from Milwaukee Water Works: https://city.milwaukee.gov/water/WaterQuality {{Webarchive|url=https://web.archive.org/web/20231204101901/https://city.milwaukee.gov/water/WaterQuality |date=2023-12-04 }}</ref> This is due to $508 million invested in water treatment and monitoring improvements since the outbreak.<ref name=":4" /><ref>Ceraso, M. (2013). ''20 years after fatal outbreak, Milwaukee leads on water testing.'' Wisconsin Water Watch.</ref> Improvements in treatment include:
⚫
* Monitoring on each stream of flow (8 streams) – previously, streams were only monitored before and after branching off (no way to monitor individual streams)

⚫
* Collection pipe for water was moved further out in the lake
* Activated charcoal filtration (Actiflo Carb) removes certain drugs, disinfectants, antibiotics<ref name=":5">Milwaukee Public Water Works. (2023). ''FAQs – Water Quality and Public Health – Water Treatment Process''. Retrieved from City of Milwaukee: https://city.milwaukee.gov/water/customer/FAQs/qualityandhealth/Water-treatment-process.htm {{Webarchive|url=https://web.archive.org/web/20230413075617/https://city.milwaukee.gov/water/customer/FAQs/qualityandhealth/Water-treatment-process.htm |date=2023-04-13 }}</ref>
* Ozone treatment
⚫
* Monitoring on each stream of flow (8 streams) – previously, streams were only monitored before and after branching off (no way to monitor individual streams)<ref name=":5" />
** Effective at treating chlorine-resistant bacteria, such as ''Cryptosporidium''
⚫
* Collection pipe for water was moved further out in the lake to draw higher quality water<ref name=":5" />
⚫
* Online monitoring/automation
* Ozone treatment<ref name=":5" /> (Effective at treating chlorine-resistant microorganisms, such as ''Cryptosporidium''<ref>USEPA. (1999, September). ''Wastewater Technology Fact Sheet – Ozone Disinfection.'' Retrieved from Wastewater Technology Fact Sheet: https://www3.epa.gov/npdes/pubs/ozon.pdf {{Webarchive|url=https://web.archive.org/web/20240125022604/https://www3.epa.gov/npdes/pubs/ozon.pdf |date=2024-01-25 }}</ref>)
⚫
* Online monitoring/automation<ref name=":5" />


== See also ==
== See also ==
Line 41: Line 48:
== Further reading ==
== Further reading ==
{{refbegin}}
{{refbegin}}
* {{cite journal | vauthors = Osewe P, Addiss DG, Blair KA, Hightower A, Kamb ML, Davis JP | title = Cryptosporidiosis in Wisconsin: a case-control study of post-outbreak transmission | journal = Epidemiology and Infection | volume = 117 | issue = 2 | pages = 297–304 | date = October 1996 | pmid = 8870627 | pmc = 2271709 | doi = 10.1017/s0950268800001473 | url = }}
* {{cite journal | vauthors = Osewe P, Addiss DG, Blair KA, Hightower A, Kamb ML, Davis JP | title = Cryptosporidiosis in Wisconsin: a case-control study of post-outbreak transmission | journal = Epidemiology and Infection | volume = 117 | issue = 2 | pages = 297–304 | date = October 1996 | pmid = 8870627 | pmc = 2271709 | doi = 10.1017/s0950268800001473 |url=}}
* {{cite web | vauthors = Gradus S | date = 10 January 2014 | title = Milwaukee, 1993: The Largest Documented Waterborne Disease Outbreak in US History. | work = Water Quality and Health Council | url = https://waterandhealth.org/safe-drinking-water/drinking-water/milwaukee-1993-largest-documented-waterborne-disease-outbreak-history/ }}
* {{cite web | vauthors = Gradus S | date = 10 January 2014 | title = Milwaukee, 1993: The Largest Documented Waterborne Disease Outbreak in US History. | work = Water Quality and Health Council |url=https://waterandhealth.org/safe-drinking-water/drinking-water/milwaukee-1993-largest-documented-waterborne-disease-outbreak-history/ | access-date = 3 December 2020 | archive-date = 11 November 2022 | archive-url=https://web.archive.org/web/20221111173619/https://waterandhealth.org/safe-drinking-water/drinking-water/milwaukee-1993-largest-documented-waterborne-disease-outbreak-history/ | url-status = dead }}
{{refend}}
{{refend}}


== External links ==
== External links ==
* [https://www.cdc.gov/parasites/crypto/index.html CDC Cryptosporidium]
* {{Cite web |url=https://www.cdc.gov/parasites/crypto/index.html |title= CDC Cryptosporidium |access-date=2020-12-03 |archive-date=2022-09-01 |archive-url=https://web.archive.org/web/20220901054447/https://www.cdc.gov/parasites/crypto/index.html |url-status=live }}
* [https://city.milwaukee.gov/water/WaterQuality Milwaukee Water Quality Website]
* {{Cite web|url=https://city.milwaukee.gov/water/WaterQuality|title=Water Quality}} Milwaukee Water Quality Website]
* [https://www.epa.gov/dwreginfo/surface-water-treatment-rules EPA Surface Water Drinking Rules]
* {{Cite web|url=https://www.epa.gov/dwreginfo/surface-water-treatment-rules|title=Surface Water Treatment Rules|first=OW|last=US EPA|date=October 13, 2015|website=www.epa.gov}}
* [https://www.epa.gov/dwreginfo/interim-enhanced-surface-water-treatment-rule-documents Drinking Water Requirements for States and Public Water Systems]
* {{Cite web|url=https://www.epa.gov/dwreginfo/interim-enhanced-surface-water-treatment-rule-documents|title=Interim Enhanced Surface Water Treatment Rule Documents|first=OW|last=US EPA|date=October 15, 2015|website=www.epa.gov}}
* [https://city.milwaukee.gov/Health/Services-and-Programs/healthlab Milwaukee Health Department Lab]
* {{Cite web|url=https://city.milwaukee.gov/Health/Services-and-Programs/healthlab|title=Laboratory}} Milwaukee Health Department Lab
* [http://waterandhealth.org/newsletter/old/03-01-1995.html Cryptosporidium and public health (Drinking Water and Health Newsletter)]
* {{Cite web |url=http://waterandhealth.org/newsletter/old/03-01-1995.html |title= Cryptosporidium and public health (Drinking Water and Health Newsletter) |access-date=2006-04-10 |archive-date=2022-03-03 |archive-url=https://web.archive.org/web/20220303172026/http://www.waterandhealth.org/newsletter/old/03-01-1995.html |url-status=dead }}
* {{cite journal | last1=Corso | first1=Phaedra S. | last2=Kramer | first2=Michael H. | last3=Blair | first3=Kathleen A. | last4=Addiss | first4=David G. | last5=Davis | first5=Jeffrey P. | last6=Haddix | first6=Anne C. | title=Costs of Illness in the 1993 Waterborne''Cryptosporidium''Outbreak, Milwaukee, Wisconsin | journal=Emerging Infectious Diseases | publisher=Centers for Disease Control and Prevention (CDC) | volume=9 | issue=4 | year=2003 | issn=1080-6040 | doi=10.3201/eid0904.020417 | pages=426–431 | pmid=12702221 | pmc=2957981 | url=https://wwwnc.cdc.gov/eid/article/9/4/02-0417_article | ref=none}}
* [https://wwwnc.cdc.gov/eid/article/9/4/02-0417_article Cost of Illness in the 1993 Waterborne Cryptosporidium Outbreak, Milwaukee, Wisconsin (CDC)]

* [http://content.nejm.org/cgi/content/abstract/331/3/161] [https://www.nejm.org/doi/full/10.1056/NEJM199407213310304 A Massive Outbreak in Milwaukee of Cryptosporidium Infection Transmitted through the Public Water Supply]
{{Milwaukee}}
{{Milwaukee}}


Latest revision as of 04:22, 23 September 2024

1993 Milwaukee cryptosporidiosis outbreak
DiseaseCryptosporidiosis
Parasite strainCryptosporidium
SourceContaminated water filtration plant
LocationMilwaukee, Wisconsin
First reportedApril 4, 1993
Confirmed cases403,000
Deaths
69

The 1993 Milwaukee cryptosporidiosis outbreak was a significant distribution of the Cryptosporidium protozoan in Milwaukee, Wisconsin, and the largest waterborne disease outbreak in documented United States history. It is suspected that The Howard Avenue Water Purification Plant, one of two water treatment plants in Milwaukee at the time, was contaminated. It is believed that the contamination was due to an ineffective filtration process.[1] Approximately 403,000 residents were affected resulting in illness and hospitalization. Immediate repairs were made to the treatment facilities along with continued infrastructure upgrades during the 25 years since the outbreak. The total cost of the outbreak, in productivity loss and medical expenses, was $96 million.[1] At least 69 people died as a result of the outbreak.[1] The city of Milwaukee has spent upwards to $510 million in repairs, upgrades, and outreach to citizens.

Epidemiology

[edit]

Cryptosporidium are a chlorine-resistant enteric pathogens that cause gastrointestinal illness (cryptosporidiosis) with symptoms such as diarrhea. Other symptoms include stomach cramps, dehydration, nausea, vomiting, fever, or weight loss.[2] Symptoms can be more severe for people who are immunocompromised, for whom diarrhea can lead to death.[3] Enteric pathogens are microorganisms that humans ingest, typically through contaminated food or water.[4] Since Cryptosporidium is a coccidian parasite, it has oocysts.[3] An oocyst is a period in the life cycle of a coccidian parasite. The oocysts in Cryptosporidium are the transmissible stage for cryptosporidiosis.[3][2]

Most reports do not specify the species of Cryptosporidium involved in the outbreak. Several species cause cryptosporidiosis in humans, with most caused by Cryptosporidium parvum and Cryptosporidium hominis.[5] However adding to the confusion, these two species were only split from each other in 2002.[5] In 2003, Phaedra S. Corso et al. imply without evidence that it was C. parvum.[1] In 2001, Alicia C. McDonald et al. clearly state that C. parvum is the cause,[6] but the 1994 source they cite does not specify the species.[7] McDonald et al. do find positive results testing blood samples with antigens derived from C. parvum,[6] but a 2018 paper from Sumeeta Khurana and Preeti Chaudhary indicate that antigen tests are not species-specific and that molecular methods are needed to differentiate other species.[8] A 2003 study by Ling Zhou et al. specifically addresses these issues and clearly identifies the pathogen in this outbreak as C. hominis.[9]

History

[edit]

On April 4, 1993, pharmacist Jeff Langer contacted a local television station after the Milwaukee Health Department did not respond to his calls regarding substantial increase in gastrointestinal complaints. Sunday evening, April 4, the station came out to interview Jeff Langer regarding the substantial increase in requests for anti-diarrhea medications. Following that television interview, April 5, 1993, Milwaukee Health Department received additional reports of gastrointestinal illness at their local hospitals and calls of complaints related to reduced water-quality aesthetic. Water aesthetics include taste, color, odor, hardness/softness, and turbidity. They are considered a secondary standard under the EPA National Primary Drinking Water Regulations (NPDWR). Although these drinking aesthetics are under the EPA NPDWR, they are not federally enforced but are standard regulations that states may choose to adopt and enforce themselves. In the spring of 1993, turbidity was the main complaint. This was corroborated by Milwaukee Water Works records of Maximal Turbidity for both water treatment plants from March through April 1993.[7]

Causes

[edit]

The root cause of the epidemic was never officially identified; however, it was most likely the result of human error at the Howard Avenue Water Treatment Plant. Initially it was suspected to be caused by runoff from upstream cattle pastures.[7] It was also thought that melting ice and snowmelt carrying Cryptosporidium may have entered the water treatment plants through Lake Michigan.[10]

MacKenzie et al. and the CDC showed that this outbreak was caused by Cryptosporidium oocysts that passed through the filtration system of one of the city's water-treatment plants, arising from a sewage treatment plant's outlet two miles upstream in Lake Michigan. This abnormal condition at the water purification plant lasted from March 23 through April 8, after which, the plant was shut down. Over the span of approximately two weeks, 403,000[11] of an estimated 1.61 million residents in the Milwaukee area (of which 880,000 were served by the malfunctioning treatment plant) became ill with the stomach cramps, fever, diarrhea and dehydration caused by the pathogen.[11] After the outbreak, cryptosporidiosis antibody rates among Milwaukee children reached 80%, compared to only 10% prior to the outbreak.[12] Deaths have been attributed to this outbreak, mostly among the elderly and immunocompromised people, such as people with AIDS.[1]

Social impact

[edit]

Reports of gastrointestinal illness began in April 1993; however, studies occurring after the outbreak confirmed that there were echoes of the epidemic beyond initial contamination as the population contracted the illness through secondary transmission.[7] This resulted in negative public sentiment toward Milwaukee Water Works. Carrie Lewis, superintendent of Milwaukee water works in 2015, explained that "people had been hurt, they felt let down by their drinking water and it took a long time for them to believe that we knew what we were doing again,"[13] It took ten years for Milwaukee citizens to begin to trust the public water supply again with the help of frequent community outreach by the utility.[13]

Current treatment in Milwaukee

[edit]

Currently, Milwaukee consistently scores as one of the highest drinking water qualities in the state.[14] This is due to $508 million invested in water treatment and monitoring improvements since the outbreak.[14][15] Improvements in treatment include:

  • Activated charcoal filtration (Actiflo Carb) removes certain drugs, disinfectants, antibiotics[16]
  • Monitoring on each stream of flow (8 streams) – previously, streams were only monitored before and after branching off (no way to monitor individual streams)[16]
  • Collection pipe for water was moved further out in the lake to draw higher quality water[16]
  • Ozone treatment[16] (Effective at treating chlorine-resistant microorganisms, such as Cryptosporidium[17])
  • Online monitoring/automation[16]

See also

[edit]

References

[edit]
  1. ^ a b c d e Corso PS, Kramer MH, Blair KA, Addiss DG, Davis JP, Haddix AC (April 2003). "Cost of illness in the 1993 waterborne Cryptosporidium outbreak, Milwaukee, Wisconsin". Emerging Infectious Diseases. 9 (4): 426–431. doi:10.3201/eid0904.020417. PMC 2957981. PMID 12702221.
  2. ^ a b Centers for Disease Control and Prevention. (2023). Parasites Glossary. Retrieved from Parasites: https://www.cdc.gov/parasites/glossary.html#oocyst Archived 2023-10-05 at the Wayback Machine
  3. ^ a b c Centers for Disease Control and Prevention. (2023). Cryptosporidiosis. Retrieved from DPDx – Laboratory Identification of Parasites of Public Health Concern: https://www.cdc.gov/dpdx/cryptosporidiosis/index.html Archived 2019-11-07 at the Wayback Machine
  4. ^ Division of Foodborne, Waterborne, and Environmental Diseases (DFWED) Home. (2023). Enteric Diseases Epidemiology Branch. Washington, D.C.: Centers for Disease Control and Prevention.
  5. ^ a b MORGAN-RYAN, UNA M.; FALL, ABBIE; WARD, LUCY A.; HIJJAWI, NAWAL; SULAIMAN, IRSHAD; PAYER, RONALD; THOMPSON, R. C. ANDREW; OLSON, M.; LAL, ALTAF; LIHUA, XIAO (November–December 2002). "Cryptosporidium hominis n. sp. (Apicomplexa: Cryptosporidiidae) from Homo sapiens". Journal of Eukaryotic Microbiology. 49 (6): 433–440. doi:10.1111/j.1550-7408.2002.tb00224.x. ISSN 1550-7408. OCLC 4630522305. PMID 12503676. Archived from the original on 25 June 2024. Retrieved 25 June 2024.
  6. ^ a b McDonald, Alicia C.; Mac Kenzie, William R.; Addiss, David G.; Gradus, M. Stephen; Linke, George; Zembrowski, Elizabeth; Hurd, Margaret R.; Arrowood, Michael J.; Lammie, Patrick J.; Priest, Jeffrey W. (1 May 2001). "Cryptosporidium parvum–Specific Antibody Responses among Children Residing in Milwaukee during the 1993 Waterborne Outbreak". The Journal of Infectious Diseases. 183 (9): 1373–1379. doi:10.1086/319862. ISSN 1537-6613. OCLC 118846463. PMID 11294669. Archived from the original on 20 January 2022. Retrieved 25 June 2024.
  7. ^ a b c d Mac Kenzie, William R.; Hoxie, Neil J.; Proctor, Mary E.; Gradus, M. Stephen; Blair, Kathleen A.; Peterson, Dan E.; Kazmierczak, James J.; Addiss, David G.; Fox, Kim R.; Rose, Joan B.; Davis, Jeffrey P. (July 21, 1994). "A Massive Outbreak in Milwaukee of Cryptosporidium Infection Transmitted through the Public Water Supply". New England Journal of Medicine. 331 (3): 161–167. doi:10.1056/NEJM199407213310304. PMID 7818640 – via CrossRef.
  8. ^ Khurana, Sumeeta; Chaudhary, Preeti (January–June 2018). "Laboratory diagnosis of cryptosporidiosis". Tropical Parasitology. 8 (1): 2–7. doi:10.4103/tp.TP_34_17. ISSN 2229-5070. OCLC 7704802362. PMC 5991046. PMID 29930899.
  9. ^ Zhou, Ling; Singh, Ajaib; Jiang, Jianlin; Xiao, Lihua (1 November 2003). "Molecular Surveillance of Cryptosporidium spp. in Raw Wastewater in Milwaukee: Implications for Understanding Outbreak Occurrence and Transmission Dynamics". Journal of Clinical Microbiology. 41 (11): 5254–5257. doi:10.1128/jcm.41.11.5254-5257.2003. ISSN 0095-1137. OCLC 9173124979. PMC 262506. PMID 14605176.
  10. ^ Botkin DB, Keller EA (2005). Environmental Science: Earth as a Living Planet (5th ed.). Wiley. p. 441. ISBN 978-0-471-48816-3.
  11. ^ a b Hoxie NJ, Davis JP, Vergeront JM, Nashold RD, Blair KA (December 1997). "Cryptosporidiosis-associated mortality following a massive waterborne outbreak in Milwaukee, Wisconsin". American Journal of Public Health. 87 (12): 2032–2035. doi:10.2105/ajph.87.12.2032. PMC 1381251. PMID 9431298.
  12. ^ "Cryptosporidium in Milwaukee's water supply caused widespread illness". Infectious Disease News. No. September 2007. Healio. September 2007. Archived from the original on 21 February 2021. Retrieved 22 February 2021.
  13. ^ a b Lewis, C. (2015, January 9). Superintendent of Milwaukee Water Works. (M. Gonzalez, & B. Gonzalez, Interviewers)
  14. ^ a b City of Milwaukee. (2022). Water Quality. Retrieved from Milwaukee Water Works: https://city.milwaukee.gov/water/WaterQuality Archived 2023-12-04 at the Wayback Machine
  15. ^ Ceraso, M. (2013). 20 years after fatal outbreak, Milwaukee leads on water testing. Wisconsin Water Watch.
  16. ^ a b c d e Milwaukee Public Water Works. (2023). FAQs – Water Quality and Public Health – Water Treatment Process. Retrieved from City of Milwaukee: https://city.milwaukee.gov/water/customer/FAQs/qualityandhealth/Water-treatment-process.htm Archived 2023-04-13 at the Wayback Machine
  17. ^ USEPA. (1999, September). Wastewater Technology Fact Sheet – Ozone Disinfection. Retrieved from Wastewater Technology Fact Sheet: https://www3.epa.gov/npdes/pubs/ozon.pdf Archived 2024-01-25 at the Wayback Machine

Further reading

[edit]
[edit]
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=1993_Milwaukee_cryptosporidiosis_outbreak&oldid=1247171960"