Hantavirus Outbreak on Cruise Ship Raises Questions About Incubation Period
As more information continues to unfold surrounding the outbreak of hantavirus aboard a cruise ship, questions about the rare virus continue to arise, including curiosity around how long it takes for symptoms to show up if someone has contracted the illness.
Three passengers aboard the MV Hondius cruise ship have died, and several others were sickened amid the outbreak of the rare family of viruses, most commonly contracted by exposure to rodent urine, droppings or saliva.
The World Health Organization said on Wednesday that there were a total of eight either confirmed or suspected cases of hantavirus. Officials have also confirmed that patients tested positive for the Andes strain of the virus.
“There are over 20 different types of hantaviruses, which are typically spread to humans after inhalation of contaminated rodent droppings,” said Kari Moore Debbink, a teaching professor in the department of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health in Baltimore.
“Andes is the only type of hantavirus that has been documented to transmit human-to-human with close contact and exposure to bodily fluids,” she told HuffPost.
Debbink explained that health officials are still doing contact tracing to determine what the possible transmission methods were on the cruise ship, but that she believes it was “likely through respiratory secretions, droplets, and/or saliva.”
Incubation Period for Andes Virus
Debbink explained that there are several different types of hantavirus, and that they each have different incubation periods. “However, in this case it’s Andes, which has an incubation period of around one to six weeks,” she said, before noting that one study showed a median time to develop symptoms after exposure was around 18 days, while another study with a smaller sample size showed an incubation period from human-to-human transmission of 12 to 27 days.
It is unclear if, and for how long, passengers and those exposed to the outbreak will be advised to quarantine. Ann Lindstrand, a WHO representative for Cape Verde, acknowledged to CBS News in an interview that the virus’s incubation period can take several weeks. Pablo Vial, an infectious disease physician at Clinica Alemana at the University of Development in Santiago, told the Science journal in an article published Tuesday that “we don’t really have an established protocol for people who have been exposed to the virus.”
Symptoms of Hantavirus
Debbink said that symptoms of the Andes virus typically begin as flu-like symptoms, such as “high fever, headaches, muscle aches and chills.” “Then a few days after the initial symptoms, respiratory symptoms including coughing, shortness of breath, shock and fluid filling the lungs can occur,” she said. “It’s fatal in 30-40% of cases that progress to respiratory symptoms.”
Hantaviruses can cause two syndromes: the hantavirus pulmonary syndrome (HPS) or the hemorrhagic fever with renal syndrome (HFRS), according to the Centers for Disease Control and Prevention. HPS is a deadly disease that affects the lungs with symptoms showing up between one to eight weeks after contact with an infected rodent. HFRS is a deadly disease that affects the kidneys with symptoms typically developing one to two weeks after exposure, the website states. The CDC explains that the severity of the disease caused by hantavirus depends on the type of hantavirus causing the syndrome.
Risk Factors and Geographic Distribution
Debbink said, generally speaking, “exposure to hantaviruses is not very common, and Andes virus is only found in South America.” “Usually the rodents that carry them tend to live in more rural areas,” she added, noting that people who are in contact with rodents or rodent droppings through their work are more at risk, but other people, like a tourist hiking in a rural area, for example, can also be at risk.
As for the U.S., the Sin Nombre virus is the most common hantavirus in the country and it is mostly in the Southwest, Debbink explained. “So people can be more or less at risk based on where they live,” she said.
While the outbreak from the MV Hondius is certainly a devastating situation, experts in public health and preventative medicine told HuffPost in an article published earlier on Wednesday that they do not believe there is a current risk to the general public. Dr. William Schaffner, a professor of preventive medicine in the department of health policy at Vanderbilt University Medical Center in Nashville, said that the outbreak was a “confined, localized problem” at the moment. “And, of course, we all have our fingers crossed that that’s how it will remain,” he said.
