Download Running Head: EMERGING INFECTIOUS DISEASE EMERGING

Running Head: EMERGING INFECTIOUS DISEASE
Emerging Infectious Disease
Sharon Herring
Ferris State University
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EMERGING INFECTIOUS DISEASE
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Abstract
Water is important to every living thing. We use water for many purposes in our daily lives.
Drinking water is necessary in order to maintain bodily functions. However, water can also
serve as a reservoir for germs to travel. Microbial contamination of water is a health risk in the
spread of infectious disease. Cryptosporidium is a parasite that can be found in water for
drinking, recreational water venues as well as human and animal feces. Cryptosporidium can
cause diarrhea and gastrointestinal problems. When Cryptosporidium levels rise significantly, it
can pose a public health concern. This paper looks at several reports and evidence-based studies
that relates to Cryptosporidium and the problems it causes, not only as individuals but also as an
infectious-disease concern to the public health system nationwide. In addition, this paper
suggests what can be done, and addresses steps to take in an initiative to reduce contamination
with Cryptosporidium.
Key words: Cryptosporidium, water, and public health
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Water serves many purposes in our everyday lives. It is important for healthy bodily
functions. Public water is widely used in recreational activities for swimming, boating, and
fishing. Water is also necessary to help plants grow.
We need our water supplies to be safe and nontoxic. Water serves as a reservoir for
germs, and we need to monitor the water we use in order to maintain public safety.
Cryptosporidium is a parasite that causes an infectious disease. If left undetected it can be a
public health concern. Despite the monitoring and filtration systems that have been set up,
Cryptosporidium continues to pass through in our water and continues to cause problems.
There is a lot of data related to Cryptosporidium and its effects on public health
nationwide. This paper evaluates various data and looks at primary sources in an effort to
educate the public about Cryptosporidium. Identifying sources and looking at what can be done
to lessen the spread of this parasite as an infectious disease is one way this paper seeks to
improve the public health.
What Is Cryptosporidium?
There are several species of Cryptosporidium. Of the various Cryptosporidium species,
there are two that are the most troublesome to humans. Cryptosporidium parvum (C-parvum) ,
and Cryptosporidium hominis (C-hominis). These species can be transmitted from animals to
humans, from humans to humans, or from humans to animals (Leitch, G. J., He, Q., 2011)
Outbreaks of Cryptosporidium have also been linked to contaminated water, and that makes this
parasite a huge public health problem.
These two species of Cryptosporidium are the least host-specific parasites and are found
in many hosts. The only stage that exists outside of the host is the oocyst. This is a tiny sporelike body surrounded by a tough protective wall that remains ineffective under cool, moist
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conditions for many months, especially where water temperatures remain low but above
freezing. It can be found in recreational and drinking water. These species of Cryptosporidium
have also been found in fish, soil, and the feces of many animals, mainly cows. The ability of
the oocysts to remain intact for so long explains why this could pose a major health concern
(Leitch, G. J., He, Q., 2011).
This one-celled organism, when ingested “then travel to the intestinal tract, where they
settle into the walls of the intestines. Eventually, more cells are produced and shed in massive
quantities into feces, where they are highly contagious” (Mayo Clinic Staff, 2011).
Cryptosporidium causes infection and irritation of the digestive track that leads to diarrhea and
watery stools. This can last for several days and up to two weeks.
In the young, the old, the immune-suppressed, and HIV-infected population, this parasite
can cause an additional burden. Infection with Cryptosporidium could turn into a chronic, longterm infection that leads to a mortality problem. It has been proven that infection with
Cryptosporidium does increase the mortality rate in HIV-infected patients when comparing
uninfected and HIV-infected patients with the same low cluster of differentiation four (CD4)
count (Leitch, G. J., He, Q., 2011).
Once ingested, oocysts settle in the digestive track of humans, and they soon begin to
multiply and the results lead to diarrhea and watery stools. In the immunosuppressed, it has been
indicated as a source of death (Mayo Clinic Staff, 2011).
A recent report from the Center for Disease Control and Prevention’s Morbidity and
Mortality Weekly Report (CDC-MMWR), indicated that Cryptosporidium has accounted for 43
cases in the United States alone, for the week ending April 6, 2013. For 2012, the reported cases
were 1,557. Thus far in 2013 the CDC reports 1,053 cases (CDC-MMWR, 2013).
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Reported Cases
In an article published by the CDC-MMWR published in 2008, Cryptosporidium was
indicated as an infectious pathogen transmitted commonly through food. Active populationbased surveillance for laboratory-confirmed cases of infections caused by Cryptosporidium was
documented. This study was conducted by the Foodborne Diseases Active Surveillance Network
(FoodNet) of CDC’s Emerging Infectious Disease Program, and was conducted throughout 10
states. This report shows that the highest incidence of Cryptosporidium infections were among
those less than 5 years old with 6.08 per 100,000 people. Those most often hospitalized were
greater than 55 years of age (CDC-MMWR, 2008). Overall, this report when compared to
earlier reports showed no significant decrease in incidence of infections for Cryptosporidium.
This indicates that despite preventative measures set in place to decrease Cryptosporidium,
infections are still a problem and increased measures are needed in order to reduce transmission.
There are multiple documented water-related events that list Cryptosporidium-related
infections among the public. In 2008 there was a dinner cruise on Lake Michigan in which 47
out of 72 passengers reported gastroenteritis. Stool specimens were collected within 13 days of
the cruise from many of the passengers who became ill. Cryptosporidium was indicated as a
cause of gastroenteritis among some of the passengers. A possible contributor to this outbreak
could have been that this cruise took place on a day when there had been heavy rainfall that
resulted in several billion liters of rainwater and storm runoff that contained sewage to be
released into the lake. Further investigation proved that lake water could have contaminated the
hose that was used to load portable water on the boat. These factors could have contributed to
the contamination of the water (Serdarevic, F., Jones, R., Weaver, K., Black, S., Ritger, K.,
Guichard, F., & Dombroski, P., 2012).
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In June 2011, firefighters from three Michigan fire departments and one fire department
from Indiana responded to a barn fire in Michigan, which was 15 miles from the Indiana border.
There were 240 one-week old calves in the burning barn. The water that was used to extinguish
the fire came from a nearby pond and a local water hydrant. The interesting point is that
“positive samples for Cryptosporidium were obtained from the stool specimens of 2 of the fire
fighters, 10 calf fecal samples and from the pond water” (CDC-MMWR, 2012). Among 34
firefighters who responded to this fire, 20 reported symptoms of gastroenteritis within 12 days of
being at this location. Out of the 20 reported cases, 9 sought medical care. Due to the fact that
only 6 submitted stool samples, the positive identification of Cryptosporidium was probably less
than the actual cases of Cryptosporidium (CDC-MMWR, 2012).
In July 2009 there was an investigation of a Cryptosporidium outbreak at a summer camp
in North Carolina. Due to an increase in campers and staff having diarrhea, the public health
department was notified. There were “46 cases identified with Cryptosporidium and 12
confirmed through lab-based evidence and 34 being probable” (CDC-MMWR 2011) due to the
fact they had been at the camp at this time and had gastrointestinal symptoms that included
diarrhea (CDC-MMWR 2011).
This report points out some interesting facts as it breaks down the possibilities of how
this could have been transmitted. The calves’ feces were an issue. Produce that had been grown
near the calves’ area that had been digested was proven as a source of exposure. In addition, the
pond, recreational water, and drinking water were considered a source of infection.
In Terrant County, Texas, in 2009, those who had attended a picnic at a man-made
chlorinated lake and recreational area complained of gastrointestinal illness. Cryptosporidium
was found in 12 stool samples of several of those who were tested. Cryptosporidium was also
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found in the sample taken from the lake. Even though the lake had been chlorinated the levels
were too low to inactivate pathogens, and those that tested positive had swallowed lake water
(Cantey, P. T., Kurian, A. K., Jefferson, D., Moerbe, M. M., Marshall, K., Blankenship, W. R., &
Hlavsa, M. C., 2012).
Analysis of Data
In the cases investigated, positive identification was made through stool samples in
humans. There was positive identification of animal feces as well as a probable source because
Cryptosporidium can be transmitted either from animal to human or human to human. Water
sources were laboratory tested and confirmed for levels of Cryptosporidium.
Probable causes of Cryptosporidium were those individuals that presented with
gastroenteritis, diarrhea, and watery stool and those that had been in an area of an outbreak at the
appropriate time. In the case in Texas, it also looked at those consuming produce from the garden
downhill from the animal barn and the water used from a pond on the same property.
Treatment of water with chlorine at high levels was proven helpful in eliminating
dangerous Cryptosporidium levels in public water venues such as water parks and public pools,
however, “it is resistant to many chlorine based disinfectants and can’t be effectively removed
by many filters” (Mayo Clinic Staff, 2011). In public lakes and waterways, the only way to
reduce risk is to be proactive. Public lakes and waterways are always going to be subject to
animal and human feces and are going to continue to be a source of Cryptosporidium.
There is no confirmed treatment for Crytosporidium once it is positively identified. For
the immunocompromised this poses an increased burden. In children, the drug nitazoxanide was
shown to reduce oocysts count but offered no hope for reduction of symptoms or how long
symptoms would last (Abubakar, I., Aliyu, S., Arumugam, C., Hunter, P., & Usman, N., 2007).
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Decreasing Cryptosporidium Exposure
What can be done to decrease exposure to Cryptosporidium? The good news is there are
some active steps everyone can take to reduce risks. At the top of the list people should wash
their hands with soap and water. This is the first way to help prevent transmission of infectious
diseases. It is also important to wash all raw fruits and vegetables and any food that is suspected
to be contaminated.
When being exposed to farm and domestic animals, especially newborns, it is important
for people to wash their hands with soap and water after handling them. It is also important to
avoid contact with the feces of animals. When cleaning up animal feces it is helpful to wear
gloves.
Due to lake water being contaminated by animal and human feces and the ability for
occocysts to survive in low temperatures, it continues to affect public health. Freezing and
boiling water does kill Cryptosporidium (Mayo Clinic Staff, 2011). Additional monitoring of
recreational water sites is necessary. People need to be careful when swimming in public areas
and lakes and be careful not to swallow any lake water. If a person has diarrhea avoid being in
the water (Michigan Department of Public Health, 2012).
Due to high tolerance, Cryptosporidium occocysts have the ability to survive in chlorine
treated pools with chlorine at 1-3 parts per million as recommended by the Center for Disease
Control (CDC) for up to 10.6 days. If occyst counts are still too high, there is a process called
hyper chlorination that is recommended to take care of contaminated water (Cantey, P. T.,
Kurian, A. K., et al, 2012). Pool codes are reviewed and approved by individual state or local
public health officials.
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The National Outbreak Reporting System (NORS) is a voluntary national surveillance
system that supports the reporting of all waterborne outbreaks and enteric disease outbreaks from
various sources including animal contact. In 2009-2010 they showed that Cryptosporidium was
indicated in a number of cases of gastroenteritis (Yoder, J. S., Wallace, R. M., et al., 2012).
Cryptosporidium poses an additional burden on the immunocompromised and can be lifethreatening. This includes individuals who are less than 5 years of age and greater than 55 years
of age and especially the HIV-infected individuals. In a review by the Cochrane library, it stated
that Cryptosporidiosis is a common problem in the HIV-infected population. Unfortunately, it
concluded that there is no real treatment for the HIV population. There was a reduced oocyst
clearance in children with the use of nitazoxanide. Overall, with the use of nitazoxanide there
was no reduction in the time or frequency of diarrhea (Abubakar, I., Aliyu S., 2007).
Summary
Cryptosporidium is a serious public health concern. Multiple cases of probable and
confirmed cases of Cryptosporidium have been studied. This parasite causes an increased
burden on the immunosuppressed, and additional treatment modalities need to be investigated.
There are some practical ways to avoid contamination of Cryptosporidium listed in this paper.
Though there are public agencies designated to help monitor our water it is important for
individuals to take initiative in protecting themselves. Awareness, education, and action will
help in reducing the incidence of Cryptosporidium outbreaks.
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References
Abubakar, I., Aliyu, S., Arumugam, C., Hunter, P., & Usman, N. (2007). Prevention and
treatment of cryptosporidiosis in immunocompromised patients. Cochrane Database of
Systematic Reviews, (1), (2012).
Cantey, P. T., Kurian, A. K., Jefferson, D., Moerbe, M. M., Marshall, K., Blankenship, W. R., &
Hlavsa, M. C. (2012). Outbreak of Cryptosporidiosis Associated With a Man-Made
Chlorinated Lake--Tarrant County, Texas, 2008. Journal of Environmental Health,
75(4), 14-19.
Cryptosporidiosis outbreak at a summer camp -- North Carolina, 2009. (2011). MMWR:
Morbidity & Mortality Weekly Report, 60(27), 918-922.
Leitch, G. J., He, Q. (2011, January). Cryptosporidiosis an overview. Journal of Biomedical
Research, 25(1), 1-16. doi:10,1016/S1674-8301911060001-8
Mayo Clinic Staff (2011, March 4). Cryptosporidium Infection-Causes. In Mayo Clinic.
Retrieved April 13, 2013, from
http://www.mayoclinic.com/health/cryptosporidium/DS00907/DSECTION=causes
MDSS. (2013, April 6). Weekly Disease Report For The Week Ending April 6th, 2013.
In Michigan Disease Surveillance System. Retrieved April 13, 2013, from
http://www.michigan.gov/documents/mdch/Current_WSR_272689_7.pdf
Michigan Department of Community Health . (2012, July). Cryptosporidiosis (“Crypto”) Fact
Sheet. Retrieved April 13, 2013, from
http://www.michigan.gov/documents/mdch/Crypto_Fact_Sheet_394815_7.pdf
Outbreak of cryptosporidiosis associated with a firefighting response -- Indiana and Michigan,
June 2011. (2012). MMWR: Morbidity & Mortality Weekly Report, 61 153-156.
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Preliminary FoodNet Data on the incidence of infection with pathogens transmitted commonly
through food -- 10 States, 2008. (2009). MMWR: Morbidity & Mortality Weekly Report,
58(13), 333-337.
Serdarevic, F., Jones, R., Weaver, K., Black, S., Ritger, K., Guichard, F., & Dombroski, P.
(2012, April). Multi-pathogen waterborne disease outbreak associated with a dinner
cruise on Lake Michigan. In NCBI (National Center for Biotechnology Information).
Retrieved April 16, 2013, from PubMed.gov.
Yoder, J. S., Wallace, R. M., Collier, S. A., Beach, M. J., & Hlavsa, M. C. (2012).
Cryptosporidiosis Surveillance -- United States, 2009-2010. MMWR Surveillance
Summaries, 61(5), 1-12.