Argentina Broadens Hantavirus Probe: CDC Biologists Join Mission to Trap and Test Rodents in Mendoza Following Deadly Cruise Ship Outbreak

Health News Journalist

BUENOS AIRES — Argentina announced on Friday, June 5, 2026, that it is expanding its investigation into the origins of a rare hantavirus outbreak that struck the MV Hondius, an Atlantic cruise ship, last month. The Argentine Health Ministry is deploying biologists from the U.S. Centers for Disease Control and Prevention (CDC) to join local specialists in trapping and testing rodents in the western province of Mendoza from June 8–12. Simultaneously, public health officials are awaiting laboratory results from Ushuaia, the southernmost city from which the cruise departed. The outbreak, which has logged between 11 and 13 confirmed or probable cases—including three deaths—was caused by the Andes hantavirus. This specific rodent-borne pathogen is endemic to parts of Argentina and Chile and is unique globally as the only hantavirus strain capable of person-to-person transmission in certain circumstances.

The Cruise Ship Outbreak and Trace-Back Challenges

The unusual cluster of infections tied to the MV Hondius has mobilized international public health agencies. According to the World Health Organization (WHO), 13 confirmed or probable cases have been linked to the cruise ship incident.

The epidemiological timeline presents a complex puzzle for investigators. The initial victims were a Dutch couple who died in April before the cruise vessel had even set sail. Epidemiologists established that the couple contracted the virus during a monthslong overland journey across Argentina and Chile prior to boarding the ship in Ushuaia.

Reconstructing their exact movements remains exceptionally challenging. Passengers from more than 20 nations have since disembarked and entered specialized quarantine facilities worldwide. Meanwhile, international tracking teams are scrutinizing detailed travel itineraries, hotel logs, and transport schedules to fully map out transmission dynamics.

The Andes Hantavirus: A Unique Pathogen

While hantaviruses exist globally—typically spreading when humans inhale airborne particles of infected rodent excreta—the Andes strain behaves differently. It remains the only documented hantavirus that can spread directly between humans, usually via close contact or respiratory droplets in household or clinical settings.

Historically, the virus carries a formidable mortality rate ranging from 30% to 50%. However, public health data indicates that prompt hospital admission and intensive supportive care can lower that figure to approximately 30%.

The outbreak arrives during a marked surge in viral activity across the region. Argentina has recorded 101 hantavirus infections since June 2025, a figure that roughly doubles the case count from the previous year. Concurrently, the mortality rate has spiked significantly, claiming the lives of nearly one-third of those infected during this period.

Deploying to Mendoza: Trapping and Testing

The upcoming field operation in Mendoza represents a critical phase of the investigation. The Dutch couple spent a portion of their vacation visiting Malargüe, a municipality located within the province, raising concerns that they may have encountered infected reservoirs there.

Claudia Perandones, head of the National Administration of Laboratories and Health Institutes (Malbrán Institute)—Argentina’s primary government medical research body—recently met with CDC investigators to finalize the logistics of the Mendoza mission. Perandones confirmed that field teams, outfitted in specialized personal protective equipment (PPE) and respiratory gear, will trap local rodents, safely harvest blood and tissue samples, and transfer the biological material to central reference laboratories in Buenos Aires for definitive genetic sequencing.

Independent public health experts stress that finding the virus in Mendoza would rewrite local epidemiological maps.

“Mendoza province currently has no confirmed history of local Andes virus circulation,” notes Dr. Helen Chu, an infectious disease epidemiologist not involved in the current field investigation. “According to academic data from the University of Mendoza, while the specific reservoir rodents are known to inhabit the region, the virus itself has never been isolated there. Uncovering an active viral reservoir would alter our understanding of the geographic boundaries of this pathogen.”

Geographic Distribution and Regional Controversy

The investigation has sparked significant tension in southern Argentina. Last month, the Health Ministry identified Ushuaia—the tourism-dependent capital of Tierra del Fuego, widely marketed as “the end of the world”—as a potential site of exposure. In response, Malbrán Institute teams sampled wild rodents in the densely wooded areas surrounding the city.

Local authorities and tourism boards in Ushuaia have strongly rejected claims that the virus originated in their jurisdiction. The Andes hantavirus typically infects a few dozen individuals annually within specific Patagonian provinces—namely Chubut, Río Negro, and Neuquén—as well as southern Chile. It has never historically been detected in the Tierra del Fuego archipelago. Results from the Ushuaia rodent screenings remain pending.

Primary Transmission Routes of Hantavirus

The typical incubation period for the virus is approximately three weeks, though symptoms can surface anywhere from 4 to 42 days following exposure.

Public Health Implications and Prevention

Despite international concern regarding the cruise ship cluster, the WHO has explicitly clarified that the Andes hantavirus does not pose a global pandemic threat, citing its historically low and self-limiting human-to-human transmission efficiency outside of close-knit clusters.

Nonetheless, the current 2025–2026 epidemiological season in Argentina has logged 73 confirmed cases, pushing the nation past its standard outbreak threshold. By comparison, the 2024–2025 cycle registered 64 cases with 14 fatalities, while the 2023–2024 period saw 82 cases and 13 deaths.

Because there is no approved vaccine or specific antiviral therapy available for the Andes strain, clinical management relies entirely on early symptom mitigation, intensive care admission, and mechanical ventilation.

Early Symptoms (Days 1–5):
[Fever & Fatigue] ➔ [Severe Muscle Aches] ➔ [Dizziness & Chills] ➔ [Abdominal Distress]

Late Symptoms (Days 2–7 of illness):
[Coughing & Congestion] ➔ [Progressive Shortness of Breath] ➔ [Acute Respiratory Failure]

Essential Field and Home Prevention Measures:

• Ventilate Prior to Entry: Open doors and windows of enclosed, unused spaces (sheds, cabins, storage units) for at least 30 minutes before entering.

• Avoid Dry Sweeping: Do not sweep or vacuum rodent droppings, as this aerosolizes viral particles. Instead, spray affected areas thoroughly with a 10% bleach solution or disinfectant and wipe utilizing protective gloves.

• Seal Entry Points: Block openings greater than one-quarter of an inch in dwellings to prevent rodent ingress.

• Secure Food Supplies: Store all food, pet provisions, and waste in rigid, tightly sealed containers.

Investigation Limitations and Outlook

Public health officials emphasize that the Mendoza field study faces notable limitations. Processing the genetic data from the trapped rodents could take up to a month, and given the extensive timeline of the travelers’ itinerary, a definitive point of origin may never be conclusively established. Furthermore, medical historians note that the frequently cited 50% mortality ceiling reflects data compiled nearly three decades ago; modern supportive protocols in intensive care units have significantly improved survival outcomes.

Ultimately, for international travelers exploring rural Patagonia or western Argentina, the outbreak serves as a reminder to practice strict rodent avoidance and seek immediate emergency care if fever and respiratory distress develop within several weeks of travel. For the global medical community, the MV Hondius incident reinforces the critical need for vigilant syndromic surveillance of returning international travelers.

Medical Disclaimer

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.

References

• https://health.economictimes.indiatimes.com/news/industry/argentina-expands-hantavirus-probe-sends-teams-to-test-rats-in-mendoza/131543064?utm_source=latest_news&utm_medium=homepage