EXPLAINER: Where did the hantavirus come from?

Cruise ship MV Hondius departed from Ushuaia on April 1, carrying more than 170 passengers and crew members. What was supposed to be a voyage across the South Atlantic was later disrupted by the spread of a rare and deadly disease.

Where did the hantavirus outbreak on MV Hondius begin?

According to Oceanwide Expeditions, which operates the MV Hondius, passengers on board came from 28 countries, with Filipinos making up the largest group at 38 individuals.

Information from the World Health Organization (WHO) showed the vessel’s itinerary included Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena, and Ascension Island.

These destinations are ecologically diverse areas known for rich wildlife and relatively undisturbed environments, according to a report by GMA News’ JP Soriano.

Timeline of the outbreak

April 6
Ten days into the voyage, a male passenger developed fever, headache, and mild diarrhea, which later progressed to respiratory distress.

April 11
The passenger died while the ship was sailing between South Georgia and Saint Helena, according to the Marine Traffic vessel tracking website.

April 24
Two weeks after his death, the passenger’s remains were disembarked in Saint Helena along with 30 other passengers, including his wife and a Swiss national.

April 25
The wife of the deceased passenger developed gastrointestinal symptoms, which worsened during her flight to Johannesburg, South Africa.

April 26
She was admitted to a hospital in Johannesburg but later died.

On the same period, another male passenger began experiencing fever, breathing difficulty, and pneumonia-like symptoms, which worsened days later.

April 27
The second male patient was evacuated from the cruise ship and admitted to an intensive care unit in South Africa.

April 28
A female passenger also developed fever and pneumonia-like symptoms.

May 2
The second female passenger later died. On the same day, the WHO was alerted to a cluster of severe acute respiratory illness cases on the vessel.

Polymerase chain reaction (PCR) testing of the second male patient in South Africa confirmed hantavirus infection.

May 4
Authorities confirmed that the same illness was also detected in another patient, including a Swiss national hospitalized in Switzerland.

May 6
Three additional passengers were admitted to hospitals in the Netherlands; two tested positive for hantavirus.

Who are the patients?

According to the WHO, the first two patients were a Dutch couple, aged 70 (male) and 69 (female), who had traveled to Argentina, Chile, and Uruguay for birdwatching before boarding the cruise ship.

They also visited areas where rodent species known to carry hantavirus are found. It is possible they were already infected before boarding, although they had not yet shown symptoms.

The third patient is a 69-year-old British national admitted to intensive care in South Africa. He was later reported to be in stable condition as of May 8.

The fourth case is a German national, while the fifth is a Swiss national currently confined at the Zurich University Hospital in Switzerland.

As of May 8, no definitive link between all cases has been established. Several other passengers are still being monitored for possible exposure.

Transmission and risk assessment

Hantavirus is typically transmitted from rodents to humans. However, the WHO noted there were no reported sightings of rats aboard the ship, raising the possibility of rare human-to-human transmission.

Health experts say such transmission may occur through close and prolonged contact, particularly involving the Andes strain of hantavirus, which is found in parts of Latin America.

This region includes areas visited by the cruise ship and the Dutch couple before boarding.

The Department of Migrant Workers said all Filipino crew members aboard MV Hondius tested negative for hantavirus but remain under monitoring along with other passengers.

The WHO stressed that the situation does not indicate the start of a pandemic and that there is currently no cause for public alarm.—with research and information from GMA News, GMA News DigiLab, and GMA News Research/MCG, GMA News