Key facts

• Sin Nombre virus (SNV) is an emerging virus that leads to a disease called hantavirus pulmonary syndrome (HPS)
• The virus was first identified in 1993 in the south western United States.
• It is primarily transmitted to humans through contact with infected rodents
• HPS is characterised by an early phase of mild and moderate symptoms including fever, headache, and fatigue, followed by sudden respiratory failure
• The case fatality rate from infection is high, at 30 to 50 per cent.

Overview

Sin Nombre virus (SNV) is a member of the hantavirus family, a group of viruses carried by rodents that can cause severe disease. Sin nombre means ‘no name’ in Spanish. The virus is primarily transmitted through contact with infected deer mice. The virus can be spread through inhalation of tiny particles of the rodent’s urine, faeces or saliva being. It is not thought to be spread from person to person.

SNV is the most common cause of HPS in North America, with about 850 cases since 1993. This disease can be very dangerous and, in some cases, fatal. The virus infects endothelial cells in the blood vessels of the lungs, heart, kidney, liver and spleen.

Signs and symptoms

Initial symptoms of a Sin Nombre virus infection are similar to the flu and can be hard to differentiate from other illnesses.

• Fever
• Body aches
• Sometimes vomiting
• Headaches
• Dizziness

Dangers and complications

Sin Nombre Virus is one of the most dangerous hantaviruses. The most significant danger associated with Sin Nombre virus is when the lungs fill with fluid, leading to respiratory failure. Around 38 per cent of those who develop respiratory symptoms will die.

Transmission

Sin Nombre virus is mainly transmitted to humans through contact with the droppings, urine, or saliva of infected deer mice. It can also be transmitted through a bite or scratch from a rodent, although this is less common. There is currently no evidence of person to person transmission of SNV, although there have been reports of human-human spread of a similar hantavirus in Argentina.

The disease affects people of any age but those most at risk are those who work in occupations such as forestry and farming – areas where the rodent is most likely to be found

Treatment

There is no specific antiviral treatment for Sin Nombre virus infections. Treatment focuses on supportive care to manage symptoms and complications.

Prevention

Preventing Sin Nombre virus infection primarily involves avoiding contact with rodents and their droppings. The risk of exposure can be reduced by taking precautions such as:

• Avoiding areas with rodent infestations.
• Keeping food and water stored in rodent-proof containers.
• Using disinfectants to clean areas where rodents may have been present.

There is no vaccine available for SNV and HPS although a vaccine against a hantavirus prevalent in China and South Korea has been developed.

History

The Sin Nombre Virus was first identified in the Four Corners region of the United States – Arizona, Colorado, New Mexico and Utah – in 1993, when a 19-year-old Native American man from the Navajo tribe died suddenly with fluid in his lungs. The virus was initially called Four Corners virus before it was officially named Sin Nombre virus.

It is one of a family of similar viruses that are found all over the world and are in two distinct groups: old world and new world hantaviruses. The old world hantaviruses are found in Africa, Asia and Europe while the new world type is found in the Americas. The new world viruses cause HPS, while the old world group causes a disease known as haemorrhagic fever with renal syndrome, and mainly affects the kidneys. Both groups are spread by rodents.

Useful links

cdc.gov/hantavirus

gavi.org/viral-most-wanted-hantaviruses

who.int/hantavirus-outbreak-toolbox

travelhealthpro.org.uk

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