"The 3-week quarantine period for the six passengers returning to Australia is one of the most stringent being used by any country. However, the passengers will continue to be monitored for at least another four weeks after that, because 42 days is considered the upper bound of the hantavirus incubation period. That timeframe should really be front and centre. It is relevant not just for the returning passengers, but also for their families and for GPs who may see them after they leave Bullsbrook. Feeling well at three weeks does not necessarily mean someone is out of the woods.

It is also important to be precise about transmission. Hantaviruses generally do not spread from person to person and are usually acquired through contact with rodent excreta. However, the Andes strain is the notable exception. That nuance matters. While the overall risk to the Australian public remains very low, it would be misleading to rely on general statements about hantaviruses when describing what appears to have happened in this specific outbreak.

This situation also highlights the challenges of managing infectious diseases on cruise ships. We saw similar issues with norovirus and during COVID-19. The Hondius outbreak appears to be the first documented instance of hantavirus linked to a cruise. Close quarters, shared indoor environments, older passenger demographics, and the international nature of cruise travel can all make containment more difficult once an infection is introduced.

Finally, the availability of facilities like the Bullsbrook quarantine centre is a less visible but important legacy of the COVID-19 response, allowing structured monitoring of returning passengers when situations like this arise."

Four Australians, one permanent resident and one New Zealander – all passengers on the cruise ship MV Hondius, are due to arrive in Western Australia in the next few hours. They have all tested negative for Hantavirus, but will be in isolation at the Bullsbrook Centre for National Resilience and will quarantine for the next 21 days. Over the last several weeks, the world has seen the evolving situation on the cruise ship with eleven passengers having confirmed cases of the Hantavirus including three deaths and one passenger currently in a serious condition. The virus is predominantly found in rodents and only in some parts of the world. The current outbreak is from the Andres strain of the ‘Hantavirus’ and was contracted when the ship docked in Argentina. The virus has a long incubation period of five to six weeks. Human infection is usually rare and occurs through exposure to environments contaminated with infected rodents. Like all viral infections the symptoms are very similar to other viral infections – feeling unwell, possible fever, some pain, aches, and lungs can be infected causing breathing difficulties. It is not a common virus and human to human infection is very rare. At this stage, the risk to WA remains extremely low and we are being vigilant, and monitoring the situation with our strong prevention, biosecurity, and surveillance measures.

"Five Australians and one New Zealand citizen from the MV Hondius cruise ship are set to arrive in Perth. While there is currently a very low risk of hantavirus transmission to the community, the situation should continue to be closely monitored. Treating staff and close contacts should use N95 or P2 respirators in line with WHO recommendations.

So far, all these people have tested negative and remain symptom free. Given that the incubation period can extend up to six weeks, the passengers will stay in a quarantine facility in Perth for at least three weeks as a precautionary measure. Once they return home, they may be asked to monitor for symptoms for a further three weeks.

The United States is following a broadly similar approach. Eighteen passengers linked to the outbreak are currently being monitored for hantavirus, with most remaining asymptomatic and in quarantine primarily at the National Quarantine Unit in Nebraska, while two others are being monitored at Emory University Hospital in Atlanta. The one passenger who tested positive is being treated in a biocontainment unit in Nebraska. The decisions will be made later on whether the asymptomatic passengers should complete quarantine in a medical facility or at home."

“The proposed quarantine plan is a sensible and proportionate public health response that errs on the side of caution. The plan should be more than sufficient given what is currently known about Andes virus transmission. Andes virus can be severe, and person-to-person transmission has been documented, but the available evidence suggests this requires very close or prolonged contact.

Given the time since possible exposure, what is known about the passengers’ movements on the ship, and the long incubation period, Australia should be able to monitor and test the returned passengers carefully and detect whether infection has occurred. I also have full confidence in colleagues at the Doherty Institute conducting sensitive diagnostic testing. By the time these passengers leave quarantine, Australians should be very confident that there is no realistic risk of onward transmission. This is exactly the kind of situation quarantine is designed for: a small, defined group of people, a known exposure window, expert testing, and time to monitor carefully. From a public health perspective, I will be sleeping easy tonight."

"The hantavirus outbreak linked to the cruise ship highlights the importance of a One Health approach to outbreak preparedness and response, as the evidence so far suggests initial spillover of Andes virus from animals to humans followed by limited human-to-human transmission. Previous Andes virus outbreaks in South America have shown incubation periods ranging from 9 to 40 days, which means additional cases could still emerge among exposed passengers and close contacts during the monitoring period. Importantly, Andes virus transmission between humans generally requires prolonged close contact, which lowers the risk of widespread community transmission.

The rapid identification of the outbreak, confirmation of the virus, and implementation of infection prevention measures are all important steps that likely reduce the chance of further transmission. However, precautionary measures should continue throughout the incubation period, including isolation, monitoring for symptoms, and careful infection control practices among caregivers. Particular attention should be paid to handling bodily fluids such as vomit and respiratory secretions. As this virus strain is not present in Australia, preventing environmental contamination and ensuring appropriate biosecurity management of waste generated from potentially exposed individuals are also important components of the public health response."

"If you’re concerned about hantavirus, especially if you’re travelling overseas soon, the best way to protect yourself and your loved ones is to wear a P2/N95 or KN95 (or higher) respirator in places where there’s poor ventilation, and you’ll be in contact with other people. Wearing a respirator will also protect you from catching other infectious respiratory pathogens like influenza virus, RSV, adenovirus, human metapneumovirus, human parainfluenza virus, SARS-CoV-2 and other coronaviruses, and rhinovirus.

These respirators are widely available in Australia through pharmacies, major supermarkets, hardware stores and online retailers. Unlike a standard surgical (baggy blue) or cloth mask, which loosely covers the nose and mouth, a P2 respirator forms a tight seal against the face and filters out 94 percent of airborne particles, including tiny droplets that can carry infectious diseases.

Because infection can also occur through contact with contaminated fluids, it’s also important to wash your hands regularly or use hand sanitiser, avoid touching your face, and take care with shared or frequently used surfaces. Hantavirus, like other microorganisms, could survive from a few hours to a few days on surfaces, so simple precautions like wiping down areas such as aeroplane tray tables and washing your clothes and hair after long journeys can provide an added layer of protection."
More at Q+A From cruise to quarantine: is Australia at risk of hantavirus?

"As we learned during COVID, Australia’s geographically isolated location means we are currently at very low risk of hantavirus outbreaks in our community. We do not have the rodent species that would lead to Andes virus becoming endemic in Australia, so our only risk is through imported cases from travellers.

The Federal Government’s announcement that it will enforce a three-week quarantine for the repatriated Australian and New Zealand residents and flight crew is good news, although it will likely be extended given the latency period between hantavirus exposure and symptom onset, which can be as long as eight weeks.

The bigger risk to Australians is from travellers who were aboard the MV Hondius, but who have not yet been quarantined, along with their secondary contacts. Reports of cruise passengers travelling onward to multiple overseas locations, including one who attended a large international conference and who is still in the community, are concerning. The window of infectious risk is about 4 days, and individuals can be infectious up to 48 hours before symptom onset. The high mortality rate and long latency period mean that there will be a heightened risk of localised Andes virus outbreaks in the coming weeks and months."

More at Q+A From cruise to quarantine: is Australia at risk of hantavirus? "

"While the risk to the wider Australian community appears to be low, this is exactly the kind of event that reminds us why pandemic preparedness matters.

Most outbreaks will not become pandemics. But each situation gives us a chance to test whether the right systems are in place. This includes surveillance, quarantine, contact tracing, communication with the public, and coordination across borders.

The response to the cruise ship passengers may look cautious, but that is appropriate when dealing with an infectious disease where there are still uncertainties and where people may have had a shared exposure. Acting early and carefully is far better than trying to catch up later.

The Andes strain of hantavirus is unusual because it can spread between people through close and prolonged contact, and may also spread through particles in the air. Understanding the science and biology of how a virus spreads is critical to getting the public health response right. Where there is evidence or concern about possible airborne spread, authorities need to act promptly with proportionate measures, including ventilation and air cleaning, masks, and appropriate isolation and quarantine.

For Australia, this should be seen as a practical test run for our protocols. Whether different agencies work together quickly and whether we are communicating risk in a way that is accurate, calm and useful.

The broader lesson is not that the public should be alarmed, but that preparedness is an ongoing responsibility. We need to keep investing in the systems, people and partnerships that allow us to respond well before a threat escalates."

"The Andes strain of the Hanta virus causing the MV Hondius outbreak has been found to spread person to person, but not very efficiently, requiring close contact over an extended period. It usually takes 2 to 6 weeks for someone to develop symptoms, and the infectious period is believed to start with symptom onset, or in the immediate lead-up.

People live in close quarters on a ship, some sharing a cabin, and all sharing dining room, lounge facilities, shuttles to shore excursions. This is why we see higher infection rates on cruises.

The first case likely contracted his infection before boarding and developed symptoms on 6th April. Between 18 and 24 days later, a further 5 people on board had become unwell, including the wife of the first case and the ship’s doctor. Two others who disembarked earlier in  April also developed symptoms around the same time. 
After a positive Hanta test was reported from a medically evacuated case on May 2nd, passengers were confined to their cabins.

Since then, 3 more cases have been reported: a woman who developed symptoms after being evacuated on May 10th, and two others have tested positive or possible on repatriation, who either had longer incubation periods, or picked up an infection from the cluster on board before the ship lockdown.

While currently well and having tested negative, the passengers returning to Australia may still be incubating the virus, and so it is wise to isolate them from each other, and those bringing them home. If they test positive or develop symptoms, they can then be cared for and won't pose a risk to others.

An initial 3 weeks in quarantine provides enough time for authorities to learn more from the WHO outbreak investigation and who was at most risk on board, and from ongoing screening following evacuation. The risk that the returnees in Australia will become unwell or infectious eases a little with every day that the remaining 125 passengers and crew test negative for Hanta."

"Most of what we know about Andes virus is from a large outbreak that occurred in Epuyén, Argentina, in late 2018 and early 2019. This outbreak resulted in 34 confirmed infections, three superspreader events, and 11 deaths. This outbreak was the first time that epidemiologists confirmed that Andes virus infection could occur after only a fleeting interaction with an infected person.

The cruise ship situation is evolving quickly, with nine confirmed and two probable cases to date, and more likely to follow. So far, all infections are in cruise ship passengers or crew. This outbreak is following a similar pattern of person-to-person transmission seen in prior Andes virus outbreaks, with people most at risk of infecting others when symptomatic.

However, there is emerging evidence that, in certain cases, the virus can be transmitted up to 48 hours before someone becomes symptomatic, and then up to 48 hours after they develop symptoms.

Two repatriated cruise ship passengers from Spain and the US who were asymptomatic tested positive for the Andes virus via PCR, which is worrisome, as it adds more evidence that people may be infectious to others without knowing that they’re carrying this potentially deadly virus."

More at Q+A From cruise to quarantine: is Australia at risk of hantavirus?"

"Hantaviruses are very rare and typically cannot spread between people. The Andes hantavirus is unique as it is the only known hantavirus capable of person-to-person transmission, with person-to-person transmission first reported in 1996 in southern Argentina. Since then, small clusters of cases have occasionally been reported where person-to-person transmission has occurred. These small clusters have primarily occurred in Argentina and Chile, where the Andes strain is endemic, and the cases have been close contacts, such as people living in the same household. Research has shown that the risk of transmission between unwell people and the healthcare workers looking after them is low, especially when appropriate infection control processes are followed.

As international experts, such as the World Health Organisation, have already stated, the risk of a large-scale outbreak because of the cruise ship cases is incredibly unlikely, and the Australian cruise ship passengers returning to Australia today pose a very low risk to the community. They are currently symptom-free, have been repatriated to Australia under supervision, and will spend time in quarantine once they arrive in the country. Given that symptoms of the Andes hantavirus typically appear 2 to 6 weeks after exposure, the passengers will be quarantined and monitored for a lengthy period. However, in Australia we have excellent infection control protocols, and it seems the government are taking appropriate steps to protect the community from any risk of transmission, as well as to care for the cruise ship passengers."

"The three-week quarantine period comes from an abundance of caution. Countries such as Chile and Argentina, where the Andes virus is endemic, often permit home quarantine for contacts for the entire incubation period if the home conditions are suitable."