"Diamond Princesses" also cry: why the coronavirus infected every sixth on board a cruise ship

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"Diamond Princesses" also cry: why the coronavirus infected every sixth on board a cruise ship
"Diamond Princesses" also cry: why the coronavirus infected every sixth on board a cruise ship

On board the Diamond Princess cruise ship in February 2020, there was a real rampant Covid-19 epidemic. The ship was quarantined, during which, in theory, passengers were supposed to sit out in their cabins. Despite this, every sixth person there fell ill. Outside of China, nowhere else is there such a number of infected people - in no other country. They began to say that this ship is the prototype of the future coronavirus epidemic around the planet. They say that since quarantine did not help here, it means that it will not contain the disease on a global scale. In fact, long before the coronavirus, cruise ship travel came to be known as "sailing towards illness." The supposedly luxurious pastime often turned into infection even before the coronavirus. It should come as no surprise that cruise liners are the preferred virus for the new virus. Why so - we will tell below.


Ships are an ancient spread of epidemics around the world. The word "quarantine" itself means "40 days", it was first used in Italy during the "black death" epidemic in the XIV century, and it was for ships that came to the port from plagued areas. In those days, insects and rats were the main carriers of epidemics, but the current outbreak of Covid-19 is a completely different matter. On modern cruise ships, everything is different: the Diamond Princess is a huge colossus with a displacement of 116 thousand tons, more than any super-battleship of the past or an aircraft carrier of the present. There are few rats and insects, but the coronavirus can be transmitted from person to person.

A month ago, on January 20, a retiree from Hong Kong who was in Japan stepped aboard the Diamond Princess and decided to return home on a cruise ship. On the twenty-fifth, he went ashore, and on February 4, ten coronavirus cases were identified on the ship. Whether the first passenger is associated with ten sick nine days later is difficult to understand. On the one hand, the coronavirus capsid normally cannot exist outside the body for more than 72 hours. On the other hand, so far Covid-19 has not been sufficiently studied to understand for sure whether someone from the crew of the liner could have had it by February 4, simultaneously infecting a dozen passengers.


On the same day, February 4, the ship was quarantined for two weeks, and passengers were asked to stay in their cabins and not leave them. Despite this, on the 19th the number of patients became 621, ten times more. At least two have already died. How did it happen?

"Swimming to sickness": why cruise ships are so vulnerable to viruses

This is not the first time that Diamond Princess has found itself at the center of a viral outbreak. Exactly four years ago, there was an outbreak of norovirus on the same ship, which affected 158 people. One of the passengers then called his voyage the cruise of the damned. As he disembarked in Sydney, he told the press: “I'm going to kiss the ground now. Not that I love Sydney asphalt that much, but as soon as I leave customs, I'll kiss him. " In December 2015, 182 cases of the same disease affected another cruise ship staying in Sydney, Explorer of the Seas.

The reason for such outbreaks is that the very nature of the sea vessel facilitates the transfer of virus capsids. There are a lot of metal door handles, namely smooth metal, as we already wrote, is the best environment for the survival of virus capsids (the flu lives on it for up to 48 hours).By touching them, a person then touches the lips, nose, face in general and brings the infection into the respiratory tract, from where it can reach the stomach (as with norovirus in 2015-2016) and lungs (as with coronavirus in 2020).


A separate big problem: people on a cruise eat in large public areas, no one cooks in their cabins. That is, the same places accumulate a lot of people touching food, which could get drops exhaled by neighbors. Because of all this, the outbreak of a viral infection on the Diamond Princess was already sorted out in the pages of Nature several years ago.

Finally, a rather specific path of spread has been recorded for the coronavirus - with waste. In Hong Kong, there was a case when a patient through a sewer riser infected a woman living several floors away. In fact, this is the same airborne pathway: when washed off in the air, a suspension of droplets is formed, which may contain molecules from feces and urine. Among them, capsids of viruses and bacterial spores are also capable of "creeping in". Of course, you can close the lid before draining the water, but, to put it mildly, not everyone does this.

Coronavirus capsids are capable of entering not only the respiratory tract, but in some cases, excreted in feces. The restrooms on a cruise ship are often crowded with low-latency passengers. In this case, a suspension of drops can be inhaled by more than one person.

Is Japan's quarantine the most ineffective in the world?

Infectious diseases specialist Kentaro Iwata from Kobe University (Japan) was so shocked by what he saw aboard the Diamond Princess that he published a video on YouTube in which he criticized the way they tried to contain the infection:

He called the situation on board the ship "completely inadequate in terms of controlling the spread of infection." Firstly, in the case of quarantine in such a place, “green zones”, where the probability of infection is low, and “red zones”, where it is high, should be distinguished. People moved around the ship virtually without restrictions. The paramedics there walked around without masks and allowed others to walk. Moreover, the local doctor stated that she could not defend herself, that she was already infected and therefore did not consider it necessary to further defend herself.

Kentaro Iwata has been researching and controlling the spread of infections for 20 years. He has traveled to various epidemics, including Ebola in Africa and SARS in China, but has never contracted local infections. This is because, as a specialist in infections, he knows how to protect against them, he says. He believes: if there was not a "general doctor" on the ship, but a person who knows what to do with such diseases, then there would be no such disorder and the spread of coronavirus.


As the Japanese notes, when the group with his participation finally got on board the liner - first having overcome many bureaucratic slingshots - then after three hours of their attempts to actively fight the disease, he was asked to leave the ship.

Anthony Fauci, head of the US National Institutes of Health, generally shares the opinion of the Japanese expert:

“The quarantine has failed. I'd love to sweeten the pill and try to be diplomatic, but he failed."

The Japanese authorities are still trying to put a good face on a bad game. At a press conference this week, introducing them to Schiegeru Omi tried to make it appear as if most of the passengers on the ship were infected even before the quarantine began, just that only four had time to show symptoms. He believes that the spread could have taken place only among those who did not live in a separate cabin, but together with another passenger, or among the crew members who were forced to contact the rest.

However, even in the data provided by him, the situation was mentioned for only 168 patients, although there were more than 600 cases on board the liner.Coming up a plausible explanation for such a number of infected (despite the fact that at the beginning of quarantine only four were able to find the virus) is such a difficult task that it is hardly possible to cope with it at all.

Lessons learned

The worst thing about the ostrich tactics of the Japanese authorities is that, trying to present the case as if there were already hundreds of patients on the liner before quarantine, they ignore not only the scale of what happened, but also its causes.

As is clear from Kentaru Iwata's statement, the ship was staffed by regular medical personnel, not infection control specialists, although it is clear that Tokyo could have identified several people with such experience at the beginning of the quarantine. This would effectively prevent many hundreds of cases of the disease. And then two of the dead - citizens of Japan, both over 80 years old, became infected on board and were taken to the coastal hospital on February 11-12 - today they could be alive.


Perhaps it was the unwillingness to admit their mistakes that led the Japanese authorities to even more dangerous decisions. The fact is that the lifting of quarantine is justified only when such an isolated object no longer poses a threat: the disease is over on it. The medieval Italian "quarantine" means 40 days because during this time the plague patients either died or recovered. But on board the Diamond Princess there were hundreds of patients - 14 infected with the new coronavirus flew to the United States alone.

It seems that the nerves of official Tokyo simply could not stand it: they could not tolerate the constantly growing number of patients and decided to send them to ground hospitals in order to avoid increased mortality on the ship, where, as we have already found out, there can be serious problems with the quality of the medical staff. The decision is logical: since the passengers of the liner began to die, it is better to complete their treatment in hospitals, where there are more opportunities. But why send knowingly sick people to the United States and other distant countries? Why not treat them at the same military hospital in Japan where the local citizens were sent? Why multiply the chances of an epidemic in other parts of the world?

The story with the Diamond Princess is indicative: the main threat during the coronavirus epidemic is not so much himself (a common infectious disease, there are many), but the inadequate response of people to him. The failure of the Japanese authorities in an attempt to organize quarantine on a cruise ship does not mean that the coronavirus is doomed to spread throughout the world. It follows from this that the medical authorities can be bad, good, or - as in the case of the Japanese - withdrawn from dealing with the problem of non-proliferation of the epidemic. And in the latter case, things really go very far.

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