not medical workers to act as instructed. the living environment of their communal living also increased the risk. there was no bias or regularity in the distribution of infected sites on the cruise ship. after searching for traces of the virus's genes, the most common place was modular bathroom floors. according to the self-defense forces central hospital, which accepted some of the patients of the cruise ship, the average age of the patients was 68 years, and the number of men and women was about half. cruise ship crews were mainly in their 30s and 50s, and passengers were mainly in their 70s. 48% of the patients had underlying disease. cardiovascular diseases such as hypertension are the most common, followed by endocrine disorder such as thyroid diseases, diabetes, respiratory diseases, and cancer in that order. the condition of patients during hospitalization was mild (41.3%) and severe (26.9%), but 31.7% had no clinical findings during the entire period. those infected got ct scans even asymptomatic and mild symptoms at the sdf central hospital, and half of them were found to be abnormalities. their ct images showed a frosted glass-like shadow, a feature of the new coronavirus pneumonia. about one-third of patients with abnormal shadows in the lungs subsequently had worsening symptoms. they often started to get worse on the 7th to 10th day of their first symptoms, which progressed relatively slowly. captain tamura, a medical officer at the sdf central hospital, believes that the progression of inflammation in the patient's lungs in the absence of subjective symptoms is one of the reasons why the infections, which were thought to be mild, seemed to worsen rapidly. they called it "silent pneumonia" in the sense of pneumonia that develops without any symptoms. it was found that the deterioration of the patient's condition can be sensed by detecting decreased spo2 (blood oxygen saturation) in the elderly and tachypnea in the young. the risk factors for mortality were mainly age (elderly people) and basic diseases, but there were a few cases in which the disease became severe even though they were neither. however, the cause was not able to be grasped. pcr test on board was widely carried out. however, there were several cases in which pcr tests showed that they were negative despite having close contact with infected patients who got ct scans and had "frosted glass-like shadows" in their lungs. the patients were supposed to have two pcr tests at intervals to leave the hospital, but in many cases the second was positive, even though the first was negative. tamura said that he felt the sensitivity of pcr test was about 70%. the percentage of "about 70%" was also stated by the doctor at the national center for global health and medicine who treated coronavirus infections. sensitivity is an index to measure the proportion of positives, in the case of 70%, 30% of actual positives may be judged as false negatives and released. in fact, there were a series of people in japan and abroad who tested positive after disembarking, even though they tested negative on board. virus transmission and evolution, novel mutations and rna recombination airborne transmission likely accounted for >50% of disease transmission on the diamond princess cruise ship, which includes inhalation of aerosols during close contact as well as longer range. with the application of the overall model (an ordinary differential equation-based susceptible-exposed-infected-recovery (seir) model with bayesian), basic reproduction number (r0) was estimated as high as 5.70 (95% credible interval: 4.23–7.79). the sars-cov-2 outbreak in this cruise most likely originated from either a single person infected with a virus variant identical to the wuhan wiv04 isolates, or simultaneously with another primary case infected with a virus containing the 11083g > t mutation. a total of 24 new viral mutations across 64.2% (18/28) of samples based on gisaid record, and the virus had evolved into at least five subgroups within 3 weeks. rooted phylogenetic tree of sars-cov-2 genomes from samples taken from people on shipboard quarantine, february 10 to february 25, 2020 increased positive selection of sars-cov-2 were statistically significant during the quarantine. linkage disequilibrium analysis confirmed that rna recombination with the 11083g > t mutation also contributed to the increase of mutations among the viral progeny. the findings indicate that the 11083g > t mutation of sars-cov-2 spread during shipboard quarantine and arose through de novo rna recombination under positive selection pressure. in three patients in diamond princess cruise, two mutations, 29736g > t and 29751g > t (g13 and g28) were located in coronavirus 3′ stem-loop ii-like motif (s2m) of sars-cov-2. although s2m is considered an rna motif highly conserved in 3' untranslated region among many coronavirus species, this result also suggests that s2m of sars-cov-2 is rna recombination/mutation hotspot.schematic representation of the s2m rna secondary structure, with tertiary structural interactions indicated as long range contacts. demographics of the 3,711 people aboard diamond princess on the 20 january cruise, 1,045 were crew and 2,666 were passengers. the median age of the crew was 36 while the median age of the passengers was 69. the passengers were 55% female and the crew was 81% male. of the 712 infections, 145 occurred in crew and 567 occurred in passengers. deaths reports of total deaths vary, reflecting difficulties in establishing causation, differing national approaches, and changes in total mortality as time went on. the london school of hygiene and tropical medicine put the figure at 9. between february and april 2020, japanese government officials declared 13 fatalities from the ship, while one other person was evacuated from the vessel and died in australia. in april 2020, the world health organization said there had been 13 deaths. all the dead were older passengers; none were from the crew. after quarantine, the remaining passengers began to disembark in late february. by the beginning of march - when there had been 7 reported deaths - all passengers and crew had gone ashore. # date age gnd. from notes ref. 1 2020.02.20 87 m japan (kanagawa) hospitalized on 2020.02.11 2 2020.02.20 84 f japan (tokyo) hospitalized on 2020.02.12 3 2020.02.23 80s m japan hospitalized on 2020.02.05 4 2020.02.25 80s m japan (tokyo) hospitalized on 2020.02.09 5 2020.02.28 70s f japan (tokyo) hospitalized on 2020.02.07 6 2020.02.28 — m united kingdom earliest report of the death of a uk citizen from covid-19. male died in japan. 7 2020.03.01 78 m australia evacuated to a hospital in perth, australia. first australian covid-19 death. male died in australia. 8 2020.03.06 — m hong kong 9 2020.03.19 70s m canada 10 2020.03.22 70s m japan 11 2020.03.22 70s m japan 12 2020.03.28 60s f hong kong 13 2020.04.09 — — japan 14 2020.04.14 70s m japan (chiba) hospitalized on 2020.02.07 two passengers died on 20 february and a third on 23 february, all three of whom were japanese citizens in their 80s. a fourth passenger, an elderly japanese man, was reported on 25 february to have died. the fifth fatality, a japanese woman in her 70s, and the sixth fatality, a british national in his 70s, both died on 28 february. a 78-year-old australian national, who was evacuated from the ship, died on 1 march in australia, making him the seventh. a hong kong national from the ship died on 6 march, making him the eighth. a canadian man in his 70s died on 19 march, making him the ninth death. two japanese male passengers in their 70s died on 22 march making them the 10th and 11th deaths. a hong kong woman in her 60s died on 28 march, making her the twelfth death. the thirteenth fatality is a japanese passenger who died on 9 april. the details concerning the passenger's age and gender were not disclosed according to their family's wishes. another japanese man in his 70s died on 14 april, making him the fourteenth fatality. itinerary itinerary datearrivedepartport80 y/o index case 20 january17:00yokohama, japanembarked 22 january7:0021:00kagoshima, japan 25 january7:0023:59hong kong, chinadisembarked 27 january7:0016:00chân mây, vietnam 28 january8:0018:00hạ long bay, vietnam 31 january7:0017:00keelung, taiwan 1 february12:0023:00okinawa, japantested positive 4 februaryyokohama, japan number of confirmed cases confirmed cases on diamond princess () date(jst)tested(cumulative)confirmed(cumulative)notes and ref(s) 3 februaryberthed at the port of yokohama 5 february3110 6 february10220calculated from reports 7 february27361 8 february27964 9 february33670 10 february439135 12 february492174calculated from reports 13 february713218 15 february930285includes 73 asymptomatic cases 16 february1,219355includes 111 asymptomatic cases 17 february1,723454includes 189 asymptomatic cases 18 february2,404542includes 254 asymptomatic cases 19 february3,011621includes 322 asymptomatic cases 20 february3,063634includes 328 asymptomatic cases 26 february4,061705includes 392 asymptomatic cases 5 march3,618*1696*2includes 410 asymptomatic cases *1: actual number of individuals tested. *2: excluding cases found after disembarkation. title=cumulative number of people infected by coronavirus on diamond princess legacy canadian documentarian mike downie's film the covid cruise, about the diamond princess outbreak, aired in november 2020 as an episode of cbc television's science documentary series the nature of things. the last cruise, an hbo documentary film about the diamond princess outbreak, was released in march 2021. american novelist and writer gay courter wrote a book in 2020, chronicling her experience aboard the ship during the crisis.