HANTAVIRUS INFECTION: TRANSMISSION, SYMPTOMS, AND TREATMENT

Why In News?

The World Health Organization (WHO) identified cases of hantavirus linked to the cruise ship MV Hondius. 

About HANTAVIRUS 

Hantaviruses are rare but deadly zoonotic viruses that spread to humans through contact with infected rodents (deer mice, cotton rats, rice rats, house mice). 

Recently, the WHO identified a rare Hantavirus outbreak on the MV Hondius cruise ship traveling from Argentina to Cape Verde, marking the first known occurrence in a confined maritime environment.

Pathogen Characteristics

• Taxonomy: Hantaviruses belong to the genus Orthohantavirus (or Hantavirus), within the family Hantaviridae (or Bunyaviridae), and the order Bunyavirales.
• Structure: Single-stranded RNA genome.
• Unique Feature: Unlike other viruses in the Bunyaviridae family, hantaviruses do not have an arthropod vector (such as mosquitoes or ticks).

Reservoirs & Transmission

Rodent Hosts: Each hantavirus species is generally tied to a specific rodent host species. 

• For example, the Deer mouse is the primary host for the Sin Nombre virus in North America, while the Long-tailed mouse carries the Andes virus in South America. 
• Infected rodents carry the virus without showing visible signs of illness.

Primary Transmission: The virus spreads horizontally among rodents through aggressive behaviors like biting. 

• Humans are infected by inhaling aerosolized viral particles from disturbed rodent urine, droppings, or saliva. 

Human-to-Human Transmission: While person-to-person spread is non-existent for most hantaviruses, the Andes virus (found in South America) is a notable exception. 

• Limited human-to-human transmission of the Andes virus has been documented. 

Clinical Syndromes

Hantaviruses cause two distinct, severe clinical syndromes depending on the geographic region and viral strain:

• Hantavirus Pulmonary Syndrome (HPS): Primarily found in the Americas (New World viruses like Sin Nombre and Andes).
• Symptoms: It starts with flu-like symptoms (fever, aches, fatigue, vomiting), then rapidly evolves into severe respiratory distress, fluid-filled lungs, and potentially fatal shock.
• Fatality: Highly lethal, with a Case Fatality Rate (CFR) ranging from 30% to 50%.
• Hemorrhagic Fever with Renal Syndrome (HFRS): Primarily found in Europe and Asia (Old World viruses like Hantaan, Dobrava, Seoul, and Puumala).
• Symptoms: These strains predominantly attack the kidneys rather than the lungs.
• Fatality: The CFR is generally much lower, ranging from <1% to 15%.

Treatment: There is no specific antiviral treatment, cure, or approved vaccine for HPS. Ribavirin, though effective for HFRS, is not effective for HPS.

Source: NDTV