Leiden University Medical Centre in the Netherlands said in a statement Thursday that it has admitted a patient with the hantavirus.

The patient arrived at the hospital Wednesday, according to LUMC.

"The department where the patient is admitted is prepared to care for patients with severe infectious diseases. During the treatment of a patient with a suspected serious contagious disease at LUMC, all precautionary measures are taken to prevent spread," the hospital said.

There are now six confirmed hantavirus cases and five suspected.

-ABC News' Zoe Magee

World Health Organization epidemiologist Maria Van Kerkhove said Thursday that the current hantavirus outbreak onboard the MV Hondius is not the same as the COVID-19 pandemic.

"I want to be unequivocal here. This is not SARS-CoV-2. This is not the start of a COVID pandemic," Van Kerkhove said. "This is an outbreak that we see on a ship."

Van Kerkhove further noted that hantavirus doesn't spread in the same way coronaviruses do, but rather requires "close, intimate contact."

Anais Legand with the WHO said that a ship makes “a very specific environment” for transmission, but that there was no indication that there is something unusual about the virus.

-ABC News' Joseph Simonetti and Zoe Magee

The World Health Organization is not considering declaring an international health emergency because the organization still believes the hantavirus outbreak is contained and the overall public risk remains low, WHO official Maria Van Kerkhove said on Friday.

The WHO said there's no evidence that the virus changed to become more transmissible or more severe.

An international study involving around 20 countries is being launched to better understand how long people stay infectious and how long the virus can stay detectable in the body, according to the WHO.

The WHO is also working with colleagues "in Argentina, in Chile, in Uruguay and around the world" to understand the origin of the hantavirus outbreak, Kerkhove said.

Kerkhove said the teams in Argentina are looking at the movements of the first cases and past hantavirus outbreaks in South America, including where the virus was found in humans and rodents.

She said this is "pure field epidemiology" and that WHO hopes to report more “very, very soon.”

WHO is also tracing people and possible exposures connected to Saint Helena, Chile, Uruguay and South Africa as the organization tries to piece together the route of the outbreak.

-ABC News’ Dada Jovanovic