Many people think that the outbreak of Hantavirus is a rural phenomenon, but in recent years, urban outbreaks have become increasingly concerning. If you're living in an urban area, it’s important to know how and why hantavirus is becoming a growing concern and how to stay protected.

Hantavirus outbreaks in urban areas are often triggered by various natural as well as man-made conditions. Understanding the conditions behind hantavirus outbreaks can help you avoid exposure and advocate for better public health practices. Preventive measures and public awareness are critical in tackling the outbreak of this disease.

Dive in to learn the key risk factors and what can be done to prevent infection. In this article we will cover more about how urban dwellings are encountering hantavirus outbreaks and factors triggering its spread.

Introduction

What is hantavirus?

Hantaviruses are a cluster of viruses which can cause severe health complications and even death.¹ These viruses can cause a number of diseases, such as hantavirus pulmonary syndrome (HPS) and heamorrhagic fever with renal syndrome (HFRS). HPS, although a rare disease, has symptoms that resemble those of the flu, rapidly progressing into life-threatening conditions of the heart and lungs.² The disease is also called Hantavirus Cardiopulmonary Syndrome because of its attack on the respiratory system, specifically the lungs.² HFRS is a severe and sometimes deadly disease that affects the kidneys.^2,1

The disease is mainly propagated by different types of rodents like rats and mice, especially when exposed to their urine, droppings, and saliva.³ Rarely it can also spread through a bite or scratch by a rodent carrying the virus. As urban areas become increasingly crowded, understanding the conditions that facilitate the spread of hantavirus in cities is essential to improving public health responses.

Let's now explore some of the factors that contribute to the spread of the hantavirus in metropolitan areas.

Common transmission sources² 

• Contact with rodent droppings.
• Sweeping or disturbing rodent waste, which releases viral particles into the air.
• Holes and gaps in buildings which allow rodents easy access.
• The rodents are attracted to campgrounds, overflowing rubbish cans, littering, and other areas around houses and buildings where food is abandoned.

Transmission methods³

• Inhalation of infectious, aerosolised saliva or excreta of rodents.
• Eating food which is either contaminated with saliva or other faecal matter of the rodents carrying the disease.
• Touching contaminated surfaces and then touching eyes, mouth, or nose.
• Scratches or bites from infected rodents.

Key environmental factors in urban settings

Urbanisation

Urbanisation causes the disruption of the natural habitat of the rodents, pushing them into urban areas, ultimately increasing human proximity. Urbanisation, geographic expansion, habitat disruption and other such migrant movements are of grave concern, potentially leading to extended pandemics.⁴

Land cover, land-use changes 

Land cover changes can increase contact between humans, wildlife, and domestic animals, raising the risk of disease spread. These changes may lead to species loss or shifts in animal populations, such as the elimination of predator species or an increase in rodent population, which can affect how diseases like hantavirus are transmitted.⁵

Influence of climatic factors

Hantaviruses are found worldwide, causing various diseases. Warmer temperatures and changing rainfall patterns can impact rodent food availability and reproduction, indirectly influencing virus transmission. Among the different studies conducted, data shows rainfall as the strongest positive link to human hantavirus cases (10 out of 13 studies, or 76.9%), followed by temperature (4 out of 13, or 30.8%). Interestingly, temperature also showed the highest rate of negative association in some cases (3 out of 13, or 23.1%), with fewer studies reporting a negative link for rainfall (15.4%) and humidity (7.7%).⁶ 

The tropical climate is favourable for the proliferation of these viruses. Tropical regions such as Latin America and the Caribbean (LAC) are favourable for the outbreak of infectious diseases. These regions are naturally exposed to climate change impacts, infectious disease outbreaks and natural disasters. Hantaviruses, causing diseases that can pass from animals to humans (zoonotic viruses), are found in various rodent species that inhabit the tropical ecosystems of Latin America and the Caribbean, where they play a significant role in virus transmission.⁶

ENSO / El Niño events

El Niño-related rainfall caused the increase in deer mice populations (the species responsible for the spread of hantavirus in the US). Southwest, preceding major hantavirus outbreaks in the Four Corners region.⁷ Changes in temperature, rainfall and vegetation significantly caused by either drought or flood result in El Niño effects. These changes are favourable for the viruses and pathogens to propagate diseases actively in the regions. Studies show that in regions affected by El Niño, disease activity can increase by about 2.5% to 28% during El Niño years compared to normal years.⁸ Although ENSO is a tropical phenomenon centred in the Pacific Ocean, its effects are far-reaching, impacting regions as far as North America and influencing global weather patterns.⁸

Poor sanitation & waste management

Overflowing garbage bins, poor waste management, and habitual littering in densely populated areas foster ideal conditions for rodent nesting and reproduction. This, in turn, increases human exposure to hantavirus through their faeces.⁹

Poor housing and overcrowding

Overpopulated areas are at higher risk of disease infestation. Many cities where there is a population control problem or where people live in poorly managed and overcrowded settings come in contact with these viruses easily, often due to gaps in the structures or due to poor sanitation.¹⁰

Lack of awareness & preventive infrastructure

Limited public awareness about hantavirus and the absence of rodent control programmes or preventive infrastructure, such as pest control, pest monitoring, and safe waste management programmes, facilitate unchecked rodent populations in urban settings. This makes human exposure more likely.

How to control the spread of hantavirus

Maintain proper sanitation

• Ensure homes, basements, surroundings, campsites and storage sites are kept clutter-free and clean
• Dispose of garbage regularly and securely to avoid attracting rodents
  

Seal entry points

• Make sure to close any gaps and holes in walls, doors, and windows to prevent rodent or any pest entry
• Install safe screens on vents and chimneys¹¹
  

Avoid direct contact with rodent waste

• Do not sweep or vacuum rodent droppings, as this may disperse the virus into the air. Instead, spray droppings with disinfectant, let it sit for some time and then clean with gloves
• Never touch the droppings with bare hands¹¹
  

Store food properly

• Store food in properly sealed containers, especially in pantries and outdoor spaces
• Avoid leaving pet food or birdseed outdoors overnight
  

Use safe cleaning practices¹¹

• Shield yourself by wearing gloves and masks when cleaning areas where rodents may have been
• Disinfect surfaces and dispose of the waste in sealed plastic bags
  

Report infestations early

• Inform local authorities or pest control services if there’s a rodent infestation in your area or building
• Encourage community awareness and participation
  

Support urban pest control programmes

• Advocate for city-level initiatives that address sanitation, rodent control, and public education
  

Summary

Hantavirus, though traditionally associated with rural areas, is becoming an emerging threat in urban environments. The increase in human-rodent interaction due to various factors such as rapid urbanisation, poor sanitation, overcrowded housing, and climate change influences like El Niño, have all contributed to its spread. 

By understanding these environmental triggers and strengthening public awareness, sanitation practices, and rodent control measures, we can reduce the risk of outbreaks in cities. Proactive prevention approaches such as early detection, enhanced urban planning, climate-resilient sustainable health responses and community-level efforts are key to staying protected.

FAQ’s

Can a person contract hantavirus from another person?

No, in most situations, hantavirus is not passed from human to human. Instead, people catch the infection after coming into contact with urine, faeces, or saliva from infected rodents.

Do all mice and rats carry the hantavirus?

Among rodents in North America, hantavirus is carried only by select species, primarily deer mice, cotton rats, rice rats, and white-footed mice. Beware, you cannot confirm if these rodents are carrying any hantavirus viruses by just looking at them. The best practice is to avoid coming in contact with any of these wild rodents, especially their droppings, urine or saliva.³ 

What symptoms signify a hantavirus infection?

HPS is a deadly lung disease. Initial symptoms usually develop between one and eight weeks following contact with an infected rodent. Common early signs may include tiredness, fever, and muscle pain, particularly in larger muscle areas such as the thighs, hips, lower back, and occasionally the shoulders. In rare instances, individuals might develop symptoms including headaches, dizziness, chills, and gastrointestinal disturbances such as nausea, vomiting, diarrhoea, or abdominal pain. Severe symptoms, including difficulty breathing and chest discomfort or pain, can develop four to ten days following the appearance of initial symptoms. In some instances, HPS can lead to death. As per the CDC, around 38% of those who show respiratory symptoms from hantavirus could die from the illness.¹

Hemorrhagic Fever with Renal Syndrome (HFRS) is a severe illness that targets the kidneys and may result in death. Symptoms generally begin within one to two weeks of exposure, although in some cases they might not appear for up to eight days. People often experience chills, nausea, and trouble seeing clearly in the initial stages. Skin rashes, eye redness or discomfort, and face flushing are probable further symptoms reported in some cases. Low blood pressure, decreased circulation (acute shock), internal bleeding from vascular leaks, and kidney failure that could result in severe fluid accumulation are potential manifestations of the latter stages of the illness.The virus that causes the infection determines the intensity of the symptoms and the illness itself.¹

Does the hantavirus have a vaccine or treatment?

Unfortunately there is no specific cure or vaccine for hantavirus. Early diagnosis, preventive care and hospitalisation for respiratory-related symptoms significantly improve health and thereby survival rate.^12,1