Tag Archives: public health

Root Cause

Measles Vaccine Provides Multiple Protections

By ThinkReliability Staff

For previously unknown reasons, children who received the measles vaccine were less likely to die from infectious diseases other than measles.   According to Michael Mina, a postdoc in biology at Princeton University and a medical student at Emory University, the difference is significant.  “In some developing countries, where infectious diseases are very high, the reduction in mortality has been up to 80 percent.  So it’s really been a mystery – why do children stop dying at such high rates from all these different infections following introduction of the measles vaccine?”

Based on epidemiological data from countries before and after the measles vaccine was introduced, scientists believe they may have an explanation for this mystery that is part correlation and part causation.  So what’s the difference (and why do we care)?

Correlation means that two or more events tend to occur about the same time and might be associated with each other, but aren’t necessarily connected by a cause-and-effect relationship.  Causation means that a specific action causes a second event to happen.  A cause-and-effect relationship results from causation.   Sometimes it’s very difficult to distinguish between the two.  This is where the importance of evidence comes in.

In this case, part of the decrease in death due to infectious diseases can be considered due to correlation.  In this case, children who received the measles vaccine must have had access to healthcare, including the measles vaccine.  If they received the measles vaccine, they were also likely to receive other vaccines and treatment for other infectious diseases, meaning their death rates from other diseases were also lower.  The measles vaccine did not cause the reduction in deaths from infectious diseases, the access to healthcare did.  Getting the measles vaccine also resulted from the same cause, access to healthcare.

In addition to this correlation, epidemiological data from several countries from prior to the introduction of the measles vaccine shows that the number of measles cases predicted the number of deaths from other infectious diseases two to three years later.  Their hypothesis, supported by studies in monkeys, suggest that the measles virus actually erases immune protection to other diseases.  So, if a child gets measles, he or she loses some of the immune system’s “memory” of how to fight diseases can also be wiped out.  Preventing a child from getting the measles (by getting a measles vaccine) is believed to prevent deaths from other infectious diseases as well.

Although more testing is needed to verify the causation, scientists hope it will provide more evidence for parents to vaccinate their children.  Epidemiologist William Moss, who studies the vaccine at John Hopkins University, says “The reduction in overall child mortality that follows measles vaccination is much greater than previously believed.  I think this paper will provide additional evidence – if it’s needed – of the public health benefits of measles vaccine.  That’s an important message in the U.S. right now and in countries continuing to see measles outbreaks.”

To view the cause-and-effect relationships (both correlation and causation) between the measles vaccine and decreased mortality from childhood infectious diseases, please click on “Download PDF” above.  To learn more about the epidemiological study, click here.

Root Cause

The Disneyland Measles Outbreak: What you Need to Know

By ThinkReliability Staff

About 100 people, including 5 Disney theme park employees, have been infected with measles after an outbreak centering around the Disney theme parks in California. According to Disney, those 5 employees have returned to work, along with other exposed employees who have proved immunity against the disease. Because the Disney theme parts are so popular with people all over the world, measles has now been found in at least 10 other counties and 5 other states in the U.S. Says Dr. James Cherry, pediatric infectious diseases expert at UCLA, “Disneyland – this is the ideal scenario. This is sort of the perfect storm. People go to Disneyland, and they went from all different counties and all different states.”

Why measles, and why now?

According to Dr. Anthony Fauci, the Director of the National Institute of Allergy and Infectious Diseases, there were an average of 88 cases a year of measles between 2001 and 2013. (Measles was declared eliminated in the US in 2000.) In 2014, there were 644 cases in 23 separate outbreaks.   Although measles is eliminated in the US, “Travelers to areas where measles is endemic can bring measles back to the US, resulting in limited domestic transmission of measles,” according to a California Department of Public Health statement.

Once measles has entered an area, it can spread quickly. Says Matt Zahn, Orange County Health Care Agency medical director, “Measles spreads very easily by air and by direct contact. Simply being in the same room with someone who has measles is sufficient to become infected.” The Centers for Disease Control and Prevention (CDC) says “Measles is so contagious, that if one person has it, 90% of the people close to that person who are not immune will also become infected.” Additionally, the measles virus can remain “active and contagious on infected surfaces for up to 2 hours,” says the CDC. That 90% makes measles “one of the most infectious or transmissible viruses that we’re aware of,” says a Cody Meissner, a professor of pediatrics at Tufts University School of Medicine.

Decreasing vaccination levels in Orange County, where the outbreak is centered, are fueling the spread of the disease. In 2006, 95% of California kindergartners were fully vaccinated for measles. Now, only 92.6% are. Local officials say the outbreak involves a significant number of people who were not immunized, either by choice or because they are too young (measles vaccines are administered starting at 12 months old) or who have other health issues precluding vaccination.

Vaccination rates of the MMR vaccine (which includes immunization against measles) have been dropping, due to increasing concerns about side effects from vaccines and decreasing concerns about the disease itself. (Click here to read our previous blog about this issue.) Says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, “The development of the measles vaccination and the elimination of measles from this country several years ago, until it bounced back no with these outbreaks, was really a triumph in medical public health endeavor. Good vaccinations, in some respects paradoxically, are victims of their own success. Now that we don’t see a lot of measles, the scare of the difficulty and the seriousness of it is not on people’s radar screen. It gets back on their radar screen when you see what is going on right now throughout the country, which could be completely avoidable if people had vaccinated their children.”

Who is at risk?

According to Orange County Health Agency Spokesperson Deanne Thompson, “It is at large in the community now, and particularly infants too young to be immunized, people with other health conditions and, of course, people who aren’t immunized need to be very concerned. [They] really should rethink that and consider getting vaccinated.”

Anyone who has not been vaccinated for measles is particularly at risk, and California state officials have warned those who have not been vaccinated or are otherwise immune to measles to stay away from the theme parks. It is possible that those who have received the vaccine can also get the disease, though it is far less likely.

What should you do?

“The best way to prevent measles and its spread is to get vaccinated,” says Dr. Ron Chapman, director of California Department of Public Health. If that isn’t possible, at this point, it is recommended to stay away from the Disney theme parks in California until the outbreak is over. If you are taking your baby out of the country, the CDC recommends vaccination at 6 months for measles. If your child does get the measles, keep in mind that’s it not something that doctors today have seen frequently, or possibly at all. The CDC is making an effort to educate physicians. Says Jane Seward, the deputy director of the Division of Viral Diseases for the CDC, “We’ve really tried to hammer home the message that if you see somebody with a febrile rash illness, ask them if they’ve gone overseas, ask them about measles in their community, and ask them about their vaccination status. Think of measles.”

To view a Cause Map, a visual root cause analysis, of this outbreak, click on “Download PDF” above.  To learn more about this issue, click here.

Root Cause

Patient zero believed to have gotten Ebola from bats

By Kim Smiley

Scientists believe they have identified the origin of the ongoing Ebola outbreak.  The first person believed to have contracted Ebola was a two-year-old boy named Emile Ouamouno from a village called Meliandou in Guinea.  The fact that patient zero was a small child is unusual since he is too young to have been a hunter or travel far from the village alone.  His exposure to bushmeat, which has been identified as a likely culprit for transmission to humans in previous Ebola outbreaks, was also limited.

So how did a young boy contract Ebola?  A Cause Map, a form of visual root cause analysis, can be built to help analyze this issue.  A Cause Map intuitively lays out the causes that contributed to a problem to show the cause-and-effect relationships.  (Click on “Download PDF” above to view a high level Cause Map.)  As the Cause Map shows, researchers believe the boy was exposed to bats that carried Ebola.

Children from the village liked to play in a nearby hollow tree filled with Angolan free-tailed bats. Researchers believe that the boy may have come into contact with either bats infected with Ebola or their feces.   Unfortunately, the tree burned in the time since the Ebola epidemic started and researchers were unable to take samples from it, so it cannot be confirmed conclusively that the bats in the tree spread Ebola.  This information would have been particularly useful because this species of bats has not been previously linked to Ebola and Angolan free-tailed bats commonly live near people.  The scientists were able to rule out larger mammals such as chimpanzees and antelopes as the source of the current outbreak.

Tracking the origins of Ebola has proved difficult, in part because Ebola is a zoonotic disease, meaning that it can be transmitted between species.  Bats have long been suspected of being carriers of Ebola, but scientists have never been able to conclusively prove which animals are responsible for human Ebola outbreaks.  Ebola outbreaks tend to occur in remote areas where it’s difficult to gather data in a timely manner, especially in the midst of an Ebola outbreak.  Cultural differences can also make research difficult because local populations are often suspicious of the researchers, many of who are foreigners.

The current Ebola outbreak has killed nearly 8,000 people and is still spreading.  As populations grow and people are exposed to more animals, outbreaks like this may become more common.  If the species responsible for spreading Ebola could be identified, researchers would be better able to prevent future Ebola cases and possibly prevent outbreaks from occurring.

If you are curious, here are some interesting articles on lessons learned during the Ebola Outbreak –

Malaria killing thousands more than Ebola in West Africa

Ebola’s lessons, painfully learned at great cost in dollars and human lives

Root Cause

Deaths and Arrests Leave Many Questioning Mass Sterilizations

By ThinkReliability Staff

The deaths of 13 women after they underwent tubal ligation (female sterilization surgery) at a government- run clinic in India have resulted in outrage and arrests, but few answers. It is known that shortly after one of these mass sterilizations on November 8th at a mobile clinic, the women became ill and died.  The doctor was arrested for performing 83 sterilizations in 6 hours when government regulations permit only 30 in a day.  (The doctor says that pressure and incentives from the government encourage more sterilization surgeries despite guidelines.)  The cleanliness of the tools used for the surgeries as well as of the clinic itself are believed to have caused infections that led to severe septic shock that resulted in these deaths.

However, patients from different clinics who had taken antibiotics from the same batch used at the sterilization clinic also became ill, raising the question of contaminated – or outright counterfeit – drugs.  The owner and son of the manufacturing clinic that provided the antibiotics were also arrested.  It’s now believe that the women exhibited signs of potential poisoning and that trace amounts of a chemical used in rat poison were found in tests of the batch of antibiotics.  The signs of poisoning and septic shock can be similar, so additional testing is needed.

Either way, it’s clear that the care these women received was substandard.  Not only is the condition of the clinics and medication in question, but also the use of these surgeries as a form of family planning, which is common in the area.  In a survey, 34% of households indicated that female sterilization was their main method of family planning. Availability of less permanent birth control and medical care are limited, and population is booming.  The government has encouraged female sterilization, not only by running the mobile clinics but also paying the women who are sterilized.  The women who died from the procedure were given 1,400 rupees, or about $23 US.

Although there is currently limited information on what exactly lead to the death of these women, an analysis of those things that went wrong can still be useful to look for solutions.  (Click “Download PDF” above to view the one-page overview of a Cause Map, or visual root cause analysis, of what is known so far.)  Each possible cause (which indicates that more evidence is needed) can be developed with additional detail when more information is available.

Post-mortem inspection of the women who were killed indicated that their deaths were due to septic shock from severe infections.  The infections were believed to have been obtained during the surgery due to dirty tools or poor conditions.  (It’s not surprising that a clinic with limited resources known for having substandard cleanliness would struggle to ensure clean equipment for 83 surgeries in 6 hours.)  If the antibiotic they were given in order to fight potential infection was adulterated (and not providing the desired active ingredients, or too little of them to be effective), it would decrease the women’s ability to fight off the infection.

The potential poisoning (supported by sickness of others who received medication from the same batch) is believed to be due to counterfeit or adulterated medication.  Preliminary testing showed the presence of a chemical used in rat poison within the medication.  Counterfeit and adulterated drugs are both a problem in India; the World Health Organization (WHO) estimates that as many of 1 in 5 drugs made in India are fake.  The US FDA prevents the importation of the antibiotic used at the clinic from India.  Drug inspectors in the area indicate that about 25% are of substandard quality due to poor manufacturing practices.  Enforcement of drug quality is limited in the area, and issues with medication are seen frequently.

As mentioned above, both the surgeon and the owners of the pharmaceutical manufacturing facility have been arrested.  Both sterilizations and the use of certain drugs have been limited in the area until the causes resulting in the women’s deaths have been determined.  What hasn’t happened (yet) is a serious look at the country’s method of family planning in hopes that these types of tragedies never happen again.

Root Cause

The Race to Develop an Ebola Vaccine

By Kim Smiley

Traditional public health methods have not been able to stop the Ebola epidemic raging in West Africa and some experts are speculating that a vaccine may be necessary to quash the outbreak.  The only problem is an approved vaccine against Ebola doesn’t exist.

A Cause Map, a visual root cause analysis, can be built to analyze this issue by intuitively laying out the causes that contribute to the problem.  A Cause Map is built by asking “why” questions and documenting the answers on the Cause Map to show the cause-and-effect relationships.

So why isn’t there an approved Ebola vaccine?  There are several promising vaccines in development, but some of them are newer efforts that haven’t had time to go through the lengthy approval process.  A few potential vaccines have been around for years, but development stalled prior to the necessary human trials.  Prior to this year, there was limited potential revenue from an Ebola vaccine because of the limited demand so it has never been a high-priority product. Demand for, and interest in, producing an Ebola vaccine, has of course skyrocketed as a result of the ongoing epidemic in West Africa and Ebola cases popping up in other countries.

Now that companies are putting significant resources in the race to produce an Ebola vaccine there are still huge logistical obstacles that must be overcome.  At least two different vaccines should be ready for large-scale human trials early next year, but actually distributing the vaccine and tracking volunteers will require significant resources.  The vaccine must be kept at a constant temperature which can be difficult in regions of West Africa without reliability electricity.  Keeping track of thousands of volunteers is always a massive undertaking, but will be even more challenging in the middle of an epidemic in a region where the medical systems are overtaxed.  There is also a chance for significant political fallout if the vaccine created by Western countries and given to poor African nations turns out to have harmful side effects.

This topic raises some really difficult ethical issues.  How much do you fast-track a vaccine?  People are dying and an effective vaccine would save lives, but distributing a vaccine prior to the normally required testing could also result in significant human suffering if there is an unexpected side effect.  When has a vaccine been tested “enough” to justify giving it to people in a high-risk environment?  Even designing the human trials requires some hard decisions.  Do you conduct a blind study with a control group, knowing that some of that group is statistically likely to be infected with a deadly disease? There is a lot of gray area and it’s difficult to know what the right answer is.  Thousands of lives may hang in the balance and there isn’t a lot precedence in how best to respond to the challenge of this Ebola outbreak.

If you’d like to learn more about this epidemic, you can read our previous blogs:

Patient With Ebola Sent Home From ER

Ebola Outbreak Claiming Lives of Medical Staff

Hundreds Affected in ‘Unprecedented’ Ebola Outbreak

 

Root Cause

The Hand is Quicker Than the Sneeze

By Kim Smiley

A new study, simply titled “How Quickly Viruses Can Contaminate Buildings and How to Stop Them”, found that a single source of contamination can spread to 40 to 60 percent of people and commonly touched objects within 2 to 4 hours.  As stated by Charles Gerba, a researcher at University of Arizona who worked on the study, “what we really learned was the hand is quicker than the sneeze in the spread of disease.”

To study the spread of viruses within a building, researchers contaminated a variety of surfaces in several different buildings with a benign virus that lives and multiplies within bacteria to use as a tracer.  The particular virus used was bacteriophage MS-2, which is similar to noroviruses which are a common cause of the stomach flu.

After some time had passed, researchers sampled surfaces that can harbor infectious organisms, such a light switches and faucet handles, to see how far the planted virus had spread. What they found was that the virus had spread to a majority of commonly touched surfaces after just two to four hours.  They also found that the bathroom wasn’t the worst offender; the break room was the most contaminated location.  (Just think how many people touch the coffee pot handle!)

The study also included an intervention phase where cleaning personal and employees were provided with quaternary ammonium compounds (QUATS) disinfectant containing wipes and instructed on proper use (at least once daily). After the use of the wipes, researchers retested the surfaces and found that the number of places where the virus was detected was reduced by 80% and the concentration of the virus was drastically reduced.

The recommended solutions that can be used to limit the spread of disease are relatively cheap and easy.  Washing hands with soap and water or using alcohol-based hand sanitizer is still the best way to reduce the spread of infectious organisms.  This study also showed that the use of wipes containing QUATS just once a day can prevent the spread of illness.  For most circumstances, neither of these practices should be cost nor time prohibitive.

This study didn’t exactly reach shocking conclusions –  all of us know we should be washing our hands after using the bathroom and before preparing food or eating – but it’s still a good reminder.  Flu and cold season is coming soon and some simple precautions can keep everybody healthier.

To view the Cause Map, a visual root cause analysis, of the results of this study – click on “Download PDF” above.

Root Cause

Ebola Outbreak Claiming Lives of Medical Staff

By ThinkReliability Staff

On July 29, 2014, the ongoing Ebola epidemic in west Africa was hit a hard blow when Dr. Sheik Humarr Khan, a leading doctor who treated Ebola patients and  national hero in Sierra Leone, died from the deadly virus.  The outbreak, which began this spring, has now infected thousands and killed nearly 900 people across Sierra Leone, Liberia, Guinea and Nigeria, including more than 90 healthcare workers who were treating victims.  It’s the most widespread and deadliest yet, due to the relative ease of travel and an apparently new strain of the disease.  (Read our previous blog about the outbreak.)

Because of the deadly and quick-spreading nature of the Ebola virus, many precautions are taken to protect healthcare workers from the disease.  Says Marie-Christine Ferir, the Emergency Coordinator of Médecins Sans Frontières/ Doctors Without Borders, “As well as the personal protective equipment that our staff wears, we have a series of strict procedures and protocols.  Our treatment centers are designed to ensure the safest possible working environment for our staff.”  Adds Dr. Tom Frieden, the Director of The Centers for Disease Control and Prevention (CDC), “We work actively to educate American health-care workers on how to isolate patients and how to protect themselves against infection.”

Yet workers are still getting sick – and dying.  In an interview with Armand Sprecher, the medical advisor to Doctors Without Borders, he noted that, though the suits worn by healthcare workers when dealing with infected patients are impervious to fluid, procedures and protocols still have to be followed.  For example, wearing or taking off the suit improperly can cause fluid transfer to the face, or hands, which then may touch the face.  An accidental needle stick can also result in a transfer of fluids that can lead to infection.

Now people in other countries are concerned Ebola may spread further.   In order to give stricken healthcare workers the best shot possible, they are generally returned to their home countries for treatment, raising concerns that their presence will allow the virus to take root there.  An American doctor and nurse were returned to the United States for treatment on August 2nd and August 4th, respectively.  Officials note that every precaution is being taken to isolate the patients and that Ebola can be spread only by bodily fluids, which requires very close contact.

Though there are no vaccines or currently approved treatment for Ebola, the infected American personnel received experimental treatment while still in Liberia. The treatment attempts to use antibodies produced by animals exposed to Ebola to help the immune system fight off the virus.  Dr. Brantly received a blood transfusion from a boy who survived Ebola under his care (surviving Ebola appears to provide immunity against re-infection).  Both vaccines and treatments are in development, but funding is difficult given the relative rarity of Ebola.

In the ongoing attempt to contain the spread of the virus, Sierra Leone has quarantined neighborhoods, cancelled public meetings and overseas trips, while Liberia has closed schools, most borders, and put state employees on leave.  The CDC has issued a Level 3 Travel Warning to Guinea, Liberia and Sierra Leone.  The World Health Organization has launched a $100 million campaign with the aim of bringing the epidemic under control, partially by providing new doctors.

To view the impacts this disease is having on the public as well as healthcare professionals, the causes of these impacts and what is being done to reduce the risk of these impacts, please click on “Download PDF” above.  Or read our previous blog to learn more about the outbreak.

 

Root Cause

Study Finds Bacteria Can Live on Airplane Surfaces for Days

By Kim Smiley

With many bodies packed into a tight space and seemingly stale air, airplanes tend to bring out the inner germaphobe in many of us.  And the latest research, especially if you just read the headlines, isn’t going to help. Researchers at the University of Auburn found that Methicillin-resistant Staphylococcus aureus (commonly known as MRSA) and E. Coli can live for days on airplane surfaces.

The experiment involved sterilizing six surfaces found on airplanes (seat pocket, arm rest, leather seat, window shade, tray table and toilet handle), introducing MRSA and E. Coli bacteria to them and then measuring how long the bacteria survived.  Typical conditions inside an airplane were stimulated and the bacteria were suspended in three different solutions (saline, simulated seat and simulated saliva) to replicated the environment inside an airplane. The survival times ranged from 8 to 2 days.  This is a little scary, especially since an estimated 1-2 percent of people in the US may be carriers of these dangerous bacteria.

The good news, and there is good news, is that the surfaces where the bacteria lived the longest, the more porous surfaces such as the seat pocket, are the least likely surfaces to actually spread the contamination.  The study also didn’t look into how much bacteria remained after the typical cleaning  by airlines between flights, but the researchers plan to look into this in the future.

So what can you do to reduce the risk of illness if you have plans to travel on an airplane soon?  The simplest thing you can do to protect yourself is to frequently wash your hands with soap or use hand sanitizer as well as avoid touching your face as much as possible.  If you feel the need to take additional precautions, you can clean the areas around your seat with a disinfectant when you board the plane.

Airline cleaning procedures can also significantly impact the spread of illness.  So the question is, how much do you trust the thoroughness of the cleaning performed by the airline?  I think I may invest in a travel-size hand sanitizer before my next flight.

To see a high level Cause Map of this issue, click on “Download PDF” above.

Root Cause

Lack of Available Treatment Leads to Fatal Heroin Overdose

By ThinkReliability Staff

The death of a young man in New Jersey on September 23, 2010 from a heroin overdose was tragic, but part of a trend becoming more and more common.  His death mirrors many of the other fatal heroin overdoses and by examining the issues that led to this fatality, solutions that could reduce the death rates from heroin overdoses across the country (and perhaps beyond) can be developed.

We will examine this particular case in depth by using a Cause Map, or visual root cause analysis. First we capture the particulars of the issue – what, when and where – as well as the impact to the goals.  The fatality is an impact to the patient safety goal, while insufficient help being available is captured as an important difference, and is also an impact to the patient services goal.

Beginning with an impacted goal (in this case, the patient safety goal), we ask why questions to determine the cause-and-effect relationships that led to the impact.  In this case, the death resulted from a heroin overdose.  Overdoses typically result from use of this specific drug, with which overdoses are not uncommon.  Though it is not clear if this played a role in this particular death, heroin overdoses can occur after a user attempts to get clean and relapses.  If the user goes back to the dose from before ending use of the drug, the body (if it has been drug free for some period of time) is unable to handle it, resulting in the overdose.

In order to overdose, heroin use has to begin.  The use of heroin is rapidly increasing, with an estimated 669,000 users by 2012.  First-time users increased from 90,000 in 2006 to 156,000 in 2012.  The reason for the increase is believed to be the comparatively inexpensive cost compared to prescription opiates.  While a gram of heroin might sell for $100, crackdowns against prescription drug “pill mills” have increased the cost of prescription opiates (like OxyContin) to $1,000 a gram.

Once heroin use has begun, quitting is extremely difficult.  While withdrawal symptoms are not life-threatening, they are extremely unpleasant (to use a massive understatement).  Because they are not life-threatening, emergency care is limited (the victim in this case was unable to be admitted to the hospital) and many insurance companies won’t cover treatment, which can be extremely expensive.  In 2012, only 2.5 million of the 23.1 million Americans who needed drug or alcohol treatment received aid at a special facility.

Hope for overdose victims is available in the form of naloxone.  Since 2001, the use of naloxone by emergency responders resulted in reversal of over 10,000 overdoses.  The Affordable Care Act should improve insurance coverage for treatment, though it may take years for this to be in effect and, with the treatment availability shortage, likely means that not everyone will get the help they need.

However, solutions that address the problem of heroin use itself are being developed.  According to Attorney General Eric Holder, “Confronting this crisis will require a combination of enforcement and treatment.  The Justice Department is committed to both.   Since 2011, the DEA has opened more than 4,500 investigations related to heroin.  And as a result of these aggressive enforcement efforts, the amount of heroin seized along America’s southwest border increased by more than 320 percent between 2008 and 2013.   Of course, enforcement alone won’t solve the problem.  That’s why we are enlisting a variety of partners – including doctors, educators, community leaders, and police officials – to increase our support for education, prevention, and treatment.”  With the help of the federal and local governments, as well as dedicated families of users, it is hoped that the tide of heroin use will be turned.  This will be the most effective way to stop overdose deaths.

To view the Outline and Cause Map, please click “Download PDF” above.  Or click here to read more.

Root Cause

Norovirus Outbreak on Cruise Ship Sickens Over 600

By Kim Smiley 

A cruise ship has once again made national headlines for a negative reason.  A norovirus outbreak on Royal Caribbean’s Explorer of the Seas sickened nearly 700 hundred people during a cruise that ended on January 29, 2014.  Noroviruses are extremely unpleasant and cause extreme stomach cramps, vomiting and diarrhea, not exactly the stuff fantastic vacation memories are made of.  According to the Centers for Disease Control and Prevention (CDC) there have been 56 gastrointestinal outbreaks on cruise ships in the past five years, but this outbreak is notable because it was one of the largest in 20 years.

This incident can be analyzed by building a Cause Map, a visual format for performing a root cause analysis that intuitively shows the cause-and-effect relationships between the causes that contribute to an issue.  A Cause Map is built by asking “why” questions and documenting the answers. ( To view a high level Cause Map of this example, click on “Download PDF”.)

In this example, the initial source of the norovirus is not known and may not be able to be determined, but a Cause Map can still be helpful in understanding how the outbreak spread and how the outbreak impacts the goals of the company.  The CDC did investigate the outbreak, but it can be difficult to determine how the norovirus was brought onboard.   Noroviruses are common, especially during the January through April peak season for norovirus infections, and cruise ships need to have a plan to deal with sick passengers because simply preventing a norovirus from coming onboard isn’t realistic.

Once a person infected with a norovirus is onboard a cruise ship, the illness can spread quickly because is highly contagious.  Noroviruses can be transmitted by contact with an infected person, consuming contaminated food and even touching contaminated surfaces such as stair handrails.  Cruise ships, along with other confined spaces such as nursing homes, are particularly susceptible to fast spreading outbreaks of norovirus because there is a large number of people in a small space and it can be a challenge to isolate sick people.  Many cruise ships also serve meals buffet style which can pass the virus quickly to a large number of people.

The cruise ship did have a plan in place to help mitigate any outbreaks and the number of ill passengers was decreasing by the time the ship returned to port.  Sick passengers were isolated to their cabins and crew increased cleaning and sanitation of the ship during the cruise.  The ship was also given an especially thorough cleaning and extra sanitizing prior to departure of the next cruise.  In order to track and help cruise ships prevent outbreaks the CDC also runs a Vessel Sanitation Program, which monitors illness at sea and provides information about disease prevention.  If plan to take a cruise, the best way you can protect yourself is by frequently and thoroughly washing your hands with soap and water.

Visit our previous blogs if you are interested in learning more about other cruise ship examples:

Engine Room Fire Results in Cruise Ship Nightmare

Cruise Ship Loses Power

The Salvage Process of Costa Concordia