How deadly is hantavirus? We answer questions from USA TODAY readers

In a post-COVID-19 world, headlines about a spreading respiratory virus can be jarring, to say the least.

Hantavirus, an illness-causing virus carried and spread by rodents, has reignited pandemic-era anxieties for some as passengers aboard a luxury cruise ship, the MV Hondius, contend with an outbreak. The Spain-bound ship and its roughly 150 passengers have been quarantined off the coast of Cape Verde for days, with eight identified infections and three deaths aboard so far.

To help make sense of the headlines, we invited readers to send in their questions and asked USA TODAY journalists to break down the answers. Still have a question that wasn't answered? Submit yours here.

Here are some of the questions you asked USA TODAY: 

What is hantavirus?

Hantavirus is a family of viruses naturally carried by rodents. While more than 50 species have been identified, a limited number of these species are known to infect humans, according to the World Health Organization. Hantavirus is most commonly spread by exposure to rat droppings, urine or saliva.

Person-to-person transmission is rare but can cause serious illness when it does occur. Some of the infected passengers aboard the MV Hondius cruise ship are believed to have caught the infection from each other.

The WHO has identified the outbreak strain aboard the ship as the Andes virus, which is believed to spread person-to-person.

Is the hantavirus the one that caused the deaths of Gene Hackman and his wife, Betsy Arakawa-Hackman?

Yes, Betsy Arakawa's cause of death was hantavirus pulmonary syndrome, one of the two conditions caused by the virus. (The other being hemorrhagic fever with renal syndrome). Gene Hackman died from natural causes after battling heart disease and complications from Alzheimer's disease, not hantavirus.

"Hantavirus" refers to a family of viruses with over 50 species, according to the Centers for Disease Control and Prevention, and the biggest difference between Arakawa's infection and that of sick cruise passengers is the mode of transmission. While authorities determined that Arakawa likely contracted it from rat droppings found around her home, at least some passengers of the MV Hondius are believed to have caught it from each other.

How deadly is it? What are the symptoms?

Several types of hantaviruses can impact humans and animals differently. In the case of humans, hantavirus infections can cause two serious syndromes: Hantavirus pulmonary syndrome (HPS), which affects the lungs, and hemorrhagic fever with renal syndrome (HFRS), which affects the kidneys.

About 38% of those who develop HPS with respiratory symptoms may die without treatment, according to the CDC, while HFRS has a 1%-15% fatality rate, depending on the type of virus causing it and treatment.

Symptoms can vary based on the type of infection and resulting illness, as per the CDC, but may include:

• Fatigue
• Fever
• Muscle aches
• Chills
• Headache
• Dizziness
• Nausea, vomiting, diarrhea and abdominal pain
• Respiratory symptoms, including coughing, chest tightness and shortness of breath

Hantavirus isn't new. Why are we worried now? Could it become a pandemic?

Hantavirus is not new, but people are concerned given the recent COVID-19 pandemic. However, the WHO has assessed the risk to the global population as low, according to a news release published on its website.

“This is not the start of an epidemic. This is not the start of a pandemic,” Dr. Maria Van Kerkhove, acting director of epidemic and pandemic management at the WHO, said in a May 7 press briefing.

The two also don't spread the same way. COVID-19 is an airborne virus that is transmitted when an infected person breathes out particles of the virus that enter the air, making it easier for the virus to spread across communities.

Hantavirus is primarily spread when people come in contact with urine, droppings and saliva from rats, according to the CDC.

One particular species of the virus, known as the Andes virus, is the only known type of hantavirus that has been found to spread from person to person, and its spread is usually contained to people who have close contact with someone who is infected. The WHO has confirmed that the Andes virus is the strain aboard the MV Hondius.

Where do US residents who traveled on the MV Hondius live?

Travelers from five U.S. states were on board the MV Hondius cruise ship. The passengers have since returned to their homes in the following states:

• Georgia
• Arizona
• California
• Texas
• Virginia

Two Georgia residents were reported to have been on the ship, according to the Georgia Department of Public Health. Both are in "good health and show no signs of infection."

In Texas, the CDC notified the Texas Department of State Health Services that two residents were passengers on the ship. DSHS agents contacted the passengers, who reported that they did not have any symptoms and were not in contact with a sick person on board the ship.

The Arizona Department of Health Services was notified of one resident who was on the cruise ship, and reportedly, an undisclosed number of residents returned to their homes in California. The Virginia Department of Health told USA TODAY that it is tracking one traveler who returned to the state.

Is there a cure for hantavirus?

There is no specific treatment or cure for hantavirus, according to the CDC. Instead, patients receive supportive care to help manage their symptoms. These generally include rest and hydration, but can escalate to interventions like intubation for respiratory distress or, in more severe cases, dialysis.

Those who develop hemorrhagic fever with renal syndrome may need hospitalization and dialysis to help their body remove toxins if their kidneys become affected or damaged. The condition, caused by hantavirus infection, can cause fever, bleeding and kidney failure. It is associated with four types of hantaviruses (Hantaan virus, Seoul virus, Puumala virus, and Dobrava-Belgrade virus), none of which is the Andes strain found on MV Hondius.

Where is the boat docking and what are the quarantine measures?

In a statement shared by the Netherlands-based cruise operator Oceanwide Expeditions on Thursday, May 7, the company said it is "continuing to monitor progress" and is sailing toward the Canary Islands, specifically the port of Granadilla (Tenerife). The boat is expected to arrive at the port in 3-4 days, but the statement did not say if it would dock once it arrived.

"Oceanwide Expeditions remains in close and continual discussion with relevant authorities regarding our exact point of arrival, quarantine and screening procedures for all guests, and a precise timeline," it said.

Is it safe to get on a plane because of hantavirus?

You are highly unlikely to catch hantavirus on an airplane, experts say.

Robert Cross, an associate professor at the University of Texas Medical Branch, told USA TODAY on Thursday that there is "virtually no risk of transmission on airplanes within the United States," though those traveling to certain parts of South America where the Andes virus strain is endemic are at slightly more risk.

Airplanes are already equipped with air filtration systems to minimize the general risk of disease spread onboard. While the risk of transmission remains very low, experts said wearing an N95 respirator and maintaining good hand hygiene by washing often are the best preventative measures.

Have a question that wasn't answered? Submit yours here.

This story has been updated to add new information.

Contributing: Natalie Neysa Alund, Eve Chen, Melina Khan, Sara Moniuszko, Zach Wichter, USA TODAY