Hantavirus: what the numbers say and why attention remains high until early June
The good news is that so far all eleven infected are passengers on the outbreak ship Hondius, which would confirm the low contagiousness
Key points
First of all the numbers: a total of eleven cases of hantavirus infection have so far been notified to the European Centre for Disease Prevention and Control (ECDC), of which eight are confirmed, two probable and one inconclusive. No new cases or deaths have been reported since the last update. Numbers, these, which also include the three people killed by the virus. The risk for the European population remains - the Ecdc reiterate - 'very low'.
The good news is that so far all eleven infected are passengers on the Hondius outbreak ship, which would confirm the low contagiousness of the virus that has been known for years and only occurs with prolonged contact as was the case with the passengers on the cruise that lasted over a month. So what to expect and until when should the alert be kept high?
The dates to remember and incubation times
To understand the postulated scenario, one must start with the dates of the outbreak cruise. Calendar in hand, here are the main dates:on 6 April patient zero, a 70-year-old Dutch citizen, falls ill on board the ship: he presents fever, headache and slight diarrhoea. On 11 April the Dutch man experienced breathing difficulties and died on board. The cause of death was not immediately determined. On 24 April the man's body was disembarked on the island of St Helena, together with his wife and about 20 other passengers, while on 25 April the Dutch woman, who was displaying symptoms of illness, took a scheduled flight from St Helena to South Africa with 88 passengers and crew members. On 26 April the Dutch woman dies in South Africa by collapsing at the airport after attempting to board a KLM flight from Johannesburg to Amsterdam to return home. These dates should be cross-referenced with the incubation time of the virus, which is up to six weeks (42 days)
Quarantines and dates to be circled
The WHO has been explaining since the very first days of the alert that despite the low contagiousness, it is likely that there will be more cases, particularly among the 180 passengers on the cruise or among their contacts, particularly the woman who flew from St Helena to Johannesburg. But how many could there be and when could they appear? It is difficult to make precise estimates, but the dates to be circled, based on incubation times, are the end of May and early June. The British tourist who had travelled on the same flight as the Dutch woman who died in Johannesburg will, for example, remain in isolation in Milan - based on the 42-day quarantine - until 6 June.
Confirming the fact that the alertness must be kept high for at least the next 20-25 days is also epidemiologist Gianni Rezza: 'If indeed the cases that are occurring were all acquired on the cruise ship, the contagion is easily explained: on a ship one practically lives together. Then one cannot exclude some further contagion, above all there may be some concern about what happened on the plane that flew from St Helena to Johannesburg, in the one from Johannesburg to Amsterdam the infected lady was only on it for a short time. If we do things right we will have to wait a few days, until the end of May, the incubation time is unfortunately long for this virus'
