Hantavirus has returned to global attention following an outbreak on a cruise ship sailing from Argentina to Europe. The disease, caused by the Andes strain of hantavirus, has drawn concern due to its limited capacity for human-to-human transmission. The World Health Organization (WHO) has stated that the risk of a global pandemic from this outbreak remains low because transmission requires prolonged close contact.
In response to these developments, the Center for Tropical Medicine at the Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada (FK-KMK UGM) organized an online talk show titled “Hantavirus: Ancaman Lama yang Kembali Mencuri Perhatian Dunia” (Hantavirus: An Old Threat Regaining Global Attention).
During the session, Dr. Riris Andono Ahmad, MPH, PhD, a lecturer in the Department of Biostatistics, Epidemiology, and Population Health at FK-KMK UGM, presented updates on the outbreak, the characteristics of the Andes virus strain, and its potential for global spread.
Riris explained that the Andes strain of hantavirus predominantly circulates in the Andes Mountains region of South America. This virus causes Hantavirus Pulmonary Syndrome (HPS), a potentially fatal respiratory condition. Unlike most other hantavirus strains, the Andes strain can be transmitted between humans, with an incubation period ranging from 4 to 42 days.
“The cause of this hantavirus outbreak is the Andes strain originating from the Andes Mountains in South America. It can cause pulmonary syndrome and be transmitted between humans,” he said on Wednesday (May. 13).
Riris noted that the cruise ship outbreak involved eight cases, six confirmed and two suspected. Three fatalities were reported among the total of 147 passengers and crew members. The affected countries include the Netherlands, South Africa, the United Kingdom, Germany, Switzerland, and Argentina.
He explained that hantavirus transmission occurs through two pathways: primary and secondary. Primary transmission occurs through human contact with rodents, including exposure to rodent feces, urine, or bites. In the Andes strain, secondary transmission may occur among humans via droplets or splashes of body fluids. However, he emphasized that the transmission mechanism is not as straightforward as COVID-19 because it requires prolonged, close contact with an infected individual.
“In the Andes strain, the pathogen can be transmitted through droplets, but it is not as easily spread as COVID because it requires close and prolonged contact,” he explained.
According to Riris, preventive measures include using personal protective equipment (PPE), maintaining hand hygiene, and avoiding close contact with infected individuals. These measures are particularly important for healthcare workers and individuals in areas with high rodent exposure.
He further explained that the WHO has assessed the situation and concluded that the risk of a global pandemic remains low. This is because transmission so far has been limited to cruise ship passengers and can be controlled through rapid isolation and contact tracing.
“WHO’s assessment shows that the pandemic risk is low because contact with infected individuals must be close and prolonged. Transmission can also be immediately contained on the ship,” he said.
In addition to the limited transmission pattern, the rapid international response has helped keep the outbreak under control. Various international health agencies have coordinated efforts for patient isolation, quarantine, and cross-border contact tracing.
Riris emphasized that hantavirus is generally classified as a zoonotic disease with primary transmission from rodents. However, specific reports on the Andes strain indicate the possibility of human-to-human transmission.
“In general, it remains a zoonosis. The Andes strain can be transmitted from person to person because it causes pulmonary disease. Since the lungs are part of our respiratory system, they can spread through droplets. However, this is not the primary mode because it requires prolonged close contact,” he added.
Alindina Anjani, an internal medicine specialist from Dr. Sardjito Hospital, presented various aspects of hantavirus, including epidemiology, transmission mechanisms, pathogenesis, and clinical manifestations. Alindina explained that hantavirus is an RNA virus classified as zoonotic and primarily transmitted through rodents such as rats and mice. Transmission to humans occurs through contact with urine, feces, saliva, or aerosolized particles from infected rodent excretions. Therefore, the presence of rodents is a critical factor in the transmission chain.
“Without rodents, transmission to humans in this way would be unlikely. Those at risk are individuals who frequently interact with rodents,” he explained.
Alindina noted that vulnerable groups include warehouse workers, farmers, forestry workers, and individuals frequently engaged in outdoor activities such as camping. The risk also increases in environments with poor sanitation or rodent infestations. In general, there are two main syndromes caused by hantavirus infection: Hantavirus Pulmonary Syndrome (HPS) or Hantavirus Cardiopulmonary Syndrome (HCPS), and Hemorrhagic Fever with Renal Syndrome (HFRS). HPS is more commonly found in North and South America, while HFRS predominates in Asia and Europe.
According to Alindina, these two syndromes have different reservoirs and viral characteristics. In HPS, the primary reservoir is wild rodents in the Americas, such as the deer mouse, whereas HFRS is more commonly transmitted through house rats, field rats, and voles found in Asia and Europe.
“The case on the cruise ship was HPS, while the more common type in Asia is HFRS. Because they differ, the reservoirs and rodent species also differ, although the transmission methods are almost similar,” she said.
She added that hantavirus transmission generally occurs through inhalation of aerosols containing viral particles from rodent urine, feces, or saliva. Human-to-human transmission is considered very rare, especially in HFRS, which has not shown significant human transmission to date.
In explaining pathogenesis, Alindina stated that HPS primarily attacks the lungs and cardiovascular system. This condition triggers progressive shortness of breath, hypoxia, severe respiratory failure, and shock.
She explained that the course of HPS consists of several phases, beginning with a prodromal phase characterized by fever, malaise, myalgia, nausea, and vomiting, followed by a cardiopulmonary phase marked by severe respiratory distress. Laboratory findings typically include thrombocytopenia, hemoconcentration, and leukocytosis.
In contrast, in HFRS, the primary target organs are the kidneys and vascular endothelium. Vascular damage due to infection leads to capillary leakage and impaired kidney function, resulting in manifestations such as high fever, hypotension, oliguria, proteinuria, hematuria, and bleeding.
Beyond clinical symptoms, she also described differences between the two syndromes. HPS tends to have a higher mortality rate, reaching approximately 30-40 percent due to respiratory failure and shock. Meanwhile, the severity of HFRS varies depending on the causative virus type, such as Hantaan, Seoul, Puumala, or Dobrava virus.
Alindina emphasized that HFRS manifestations often resemble those of other tropical infectious diseases, requiring special attention in the differential diagnosis. Diseases to consider include dengue hemorrhagic fever, leptospirosis, malaria, disseminated intravascular coagulation (DIC), hemolytic uremic syndrome, sepsis, and scrub typhus. She noted that symptom overlap can delay diagnosis if healthcare workers are not alert to the possibility of hantavirus infection, particularly in patients with a history of rodent exposure or in high-risk environments.
Alindina urged the public to recognize, report, and jointly prevent transmission to maintain environmental health and break the hantavirus transmission chain.
Through this activity, the Center for Tropical Medicine FK-KMK UGM aims to increase awareness among the public and healthcare workers regarding zoonotic disease threats that may re-emerge. Understanding risk factors, transmission mechanisms, and early symptom recognition is expected to support faster and more accurate prevention and case management.
Writer: Zabrina Kumara
Editor: Gusti Grehenson
Post-editor: Rajendra Arya
Photo: Adobe Stock