Hantavirus, especially hantavirus pulmonary syndrome (HPS), is a zoonotic disease primarily transmitted through contact with infected rodents, posing significant public health risks in Latin America and the Caribbean (LAC) where biodiversity is high.[1] Notably, rodent species like those in the Cricetidae family serve as reservoirs for various hantavirus strains, including the Andes virus (ANDV), which uniquely transmits between humans.[2] Climate change, with its effects on rainfall, temperature, and extreme weather patterns, is increasingly altering environmental conditions in these regions, amplifying rodent population dynamics and thus the potential for hantavirus outbreaks.[3]
Hantavirus dynamics in Latin America and the Caribbean: ecology, hosts, and climate change
In Latin America and the Caribbean (LAC), where biodiversity is high, rodent species like those from the Cricetidae family act as major reservoirs for hantaviruses. These regions also face the challenge of distinguishing hantavirus infections from other endemic diseases with similar symptoms, such as dengue and Zika. Notable hantavirus strains in LAC include the Andes virus (ANDV), which is capable of human-to-human transmission, and Laguna Negra virus (LANV). The diversity of hantavirus species in South America is among the highest globally, influenced by the distribution of various rodent species that thrive in disturbed ecosystems, such as agricultural lands.
All hantaviruses are closely linked to specific mammalian hosts with which they've co-evolved, initially thought to be limited to rodents like rats, mice, and voles. Recently, insectivores such as shrews and moles have also been identified as hosts.[4]
Hantavirus transmission varies significantly among species. Unlike other members of the Bunyaviridae family, hantaviruses do not have arthropod vectors. Some, like the Sin Nombre virus (SNV), spread only through direct contact with infected body fluids, often during aggressive behavior or grooming. Others, such as Puumala, Seoul, and Hantaan viruses, can also spread indirectly through inhalation of contaminated rodent excreta.[4]
Climate and environmental changes significantly impact hantavirus transmission by altering rodent population dynamics. In LAC, intense hydrometeorological events linked to climate change are predicted to further exacerbate these risks, especially as rodent habitats expand into human environments. Consequently, understanding the relationship between climate factors and hantavirus transmission is crucial for preparing public health responses in these regions.[1]
Excess moisture creates favorable conditions for rodents in human areas by, flooding their natural habitats, driving them to seek shelter in urban spaces.[5] On the flip side, droughts can also force rodents out of arid environments in search of water and food in human settlements. Cities experience higher temperatures due to urban heat island effects, making them more hospitable to rodents seeking warmer conditions. All of the above encourages their migration into human environments.
Rodent population and migration changes during El Niño years affect hantavirus transmission.
Ecosystem distributions
Climate change disrupts the ecosystem especially concerning hantavirus epidemiology. The impacts of climate change are shown in events such as altered precipitation patterns and shifts in water cycles. In warmer water climates the rodent populations tend to increase along with food and shelter becoming accessible.[3] These rodents are the primary hosts of hantavirus and can then spread the virus more quickly. Climatic factors such as rainfall and temperature impact rodent population density, with milder winters and increased food sources contributing to population booms that can elevate the risk of hantavirus transmission to humans.
Climate change can lead to increased agricultural activities and deforestation. These events directly affects the habitats of rodents which results in them being forced to move to areas closer to human settlements. For example as forests are cleared for agriculture, rodents that lived there are forced to move into human homes and structures.[6] This leads to a higher risk of Hantavirus transmission as people are more likely to come into contact with infected rodent dropping, urine, or saliva.
Increased frequency of extreme weather events, such as floods and droughts, also alters the availability of resources for rodents. These disturbances further push rodents toward urban and peri-urban areas, increasing the chances of contact with humans. Essentially, the disruption of natural ecosystems by climate change creates a more favorable environment for rodent populations and their diseases, like Hantavirus, to thrive.[6]
Climate change does not just affect the climate in a direct sense; it transforms entire ecosystems, altering the habitats of disease vectors like rodents, changing patterns of disease transmission, and raising the risk of zoonotic infections like Hantavirus. Addressing climate change, deforestation, and unsustainable agricultural practices is crucial for controlling the spread of such diseases.[1]
Zoonotic spillover events
Zoonotic spillover
Human-Rodent Interactions: Changes in land use, such as deforestation, agricultural expansion, and urbanization, increase human contact with rodent habitats, amplifying exposure risk. Occupational and recreational activities in rural areas also heighten exposure risks.
Climate change leads to an altered precipitation of warmer temperature patterns, this results in a boost in vegetation growth and availability of food sources for rodents.[1] An example of this is that higher perception can support more robust crop and grass growth which causes an increase in food supply and supports larger rodent populations.[7] Studies have shown that an increase in food availability leads to higher rodent reproduction rates and population. This particularly happens in periods of increased rainfall and warmer winters as well as breeding seasons, rodents having higher survival in the winter and warmer temperatures contributes to the longer breeding seasons as well as improved survival rates among these rodents.[1] Evidently this increases the numbers of hantavirus carrying rodents and a greater risk of human exposure through contact with droppings, saliva and nesting materials.
Climate zones shifting due to the rapid warming temperatures are causing rodents to migrate into previously inhospitable areas, often closer to human settlements. For example increased temperatures at higher altitudes allow rodents to expand into regions where they were previously rare to be spotting but now have turned into a hotspot for potential zoonotic transmission of hantavirus.[8]
Seasonality: Hantavirus outbreaks often exhibit seasonal patterns, aligning with periods when rodent activity peaks. For example, spring and summer typically see increased cases in temperate regions as rodent populations and human outdoor activities both surge.
Climate change increase the likelihood of zoonotic spillover infection of Hantavirus from rodents to humans by causing droughts, floods, and wildfires have resulted in the displacement of both rodents and humans from their natural habitat. Rodents often relocate to human occupied areas in search of shelter and food, resulting in the increase of hantavirus spillover into human populations.[5] Rodents enter homes, farms, schools, and any areas humans typically reside, causing the risk of hantavirus transmission to be amplified.[1]
Climate change has generated shifts in land use, including agricultural expansion into areas which were previously unused, overlapping with rodent habitats. Farmland expansions into the natural habitats of rodents increase the transmission of hantavirus. Studies in Brazil and Argentina indicate that increased agricultural activity in rodent habitat correlates with higher hantavirus infection rates among nearby human populations.[1] Rodents are increasingly drawn to cities where food and shelter are more accessible, this means an influx of rodents are approaching urban areas, all rodents migrating to urban areas allows rodents to thrive in close proximity to humans thus raising spillover risks.
Extreme weather events such as prolonged droughts, intense storms, and temperature rising drives not only rodents but also humans to abundant resources. Both rodents and humans drawn to the same resources amplifies the likelihood of hantavirus transmission in these regions. During droughts rodents may congregate and scare water sources also used by humans, this creates a high contact area, likely to transmit hantavirus through water.[5] Temperature and humidity levels rising can make hantavirus survive longer outside of the host. Rodent droppings and nesting materials are warm, if the temperature is warm and keeps rising the resting materials will be able to stay long therefore allowing the virus to stay alive longer.[7] Moist environments also allow the virus to remain infectious longer. All of these factors increase the risk of exposure for humans in affected areas. Particularly following extreme weather events that disturb natural rodent habitats forcing relocation.
Population focus
Climate change is expected to influence hantavirus outbreaks by impacting the populations of rodent hosts that carry the virus. Changes in temperature, rainfall, and food availability can cause fluctuations in rodent population densities, affecting the frequency and geographic spread of hantaviruses. For example, elevated temperatures in West-Central Europe have been linked to increased outbreaks of Puumala hantavirus, driven by higher seed production and bank vole population growth.[1] Similarly, the 1993 hantavirus outbreak in the U.S. Four Corners region followed a 20-fold increase in rodent populations due to increased rainfall from the 1992–1993 El Niño, illustrating how climate-related factors can amplify hantavirus risks.[6]
El Niño's effect on carrier populations
ENSO, a climate phenomenon that alternates between warmer El Niño and cooler La Niña phases, disrupts global weather patterns, influencing rainfall, drought, and temperature fluctuations. During El Niño events, warmer sea surface temperatures shift weather patterns, increasing rainfall in some regions like South America and East Africa while causing droughts in areas such as Southeast Asia and Australia. Global warming is expected to further intensify these climate anomalies, potentially increasing the frequency and severity of ENSO events.
In the southwestern United States, the 1993 hantavirus outbreak serves as a prime example of how ENSO can exacerbate disease risks.[3] Unusual rains followed by drought led to a surge in the deer mouse population, which transmits hantavirus through excretions that humans can inhale, resulting in the often fatal hantavirus pulmonary syndrome (HPS). ENSO-driven rainfall increases food sources for rodents, indirectly raising the risk of human exposure to hantavirus.[8]
Rodents exhibit seasonal breeding patterns, sensitive to prolonged breeding seasons caused by warmer temperatures during ENSO. Rodent numbers tend to peak in winter after heavy ENSO precipitation, with increased hantavirus prevalence in the year following the event. Hantavirus-positive rodents increased in the year after ENSO events, with higher infection rates in areas with dense vegetation. Human Cases of Hantavirus increase the year after an ENSO event, coinciding with elevated rodent populations.[6] Studies link ENSO events with a rise in human hantavirus cases, especially in the year following the event.[9]
Related Research Articles
A zoonosis or zoonotic disease is an infectious disease of humans caused by a pathogen that can jump from a non-human vertebrate to a human. When humans infect non-humans, it is called reverse zoonosis or anthroponosis.
Orthohantavirus is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family Hantaviridae within the order Bunyavirales. Members of this genus may be called orthohantaviruses or simply hantaviruses.
Sin Nombre orthohantavirus (SNV), a member of the genus Orthohantavirus, is the prototypical etiologic agent of hantavirus cardiopulmonary syndrome (HCPS).
An emergent virus is a virus that is either newly appeared, notably increasing in incidence/geographic range or has the potential to increase in the near future. Emergent viruses are a leading cause of emerging infectious diseases and raise public health challenges globally, given their potential to cause outbreaks of disease which can lead to epidemics and pandemics. As well as causing disease, emergent viruses can also have severe economic implications. Recent examples include the SARS-related coronaviruses, which have caused the 2002–2004 outbreak of SARS (SARS-CoV-1) and the 2019–2023 pandemic of COVID-19 (SARS-CoV-2). Other examples include the human immunodeficiency virus, which causes HIV/AIDS; the viruses responsible for Ebola; the H5N1 influenza virus responsible for avian influenza; and H1N1/09, which caused the 2009 swine flu pandemic. Viral emergence in humans is often a consequence of zoonosis, which involves a cross-species jump of a viral disease into humans from other animals. As zoonotic viruses exist in animal reservoirs, they are much more difficult to eradicate and can therefore establish persistent infections in human populations.
Seoul orthohantavirus (SEOV) is a member of the genus Orthohantavirus of rodent-borne viruses, and is one of the four hantaviruses that are known to cause Hantavirus hemorrhagic fever with renal syndrome (HFRS). It is an Old World hantavirus; a negative sense, single-stranded, tri-segmented RNA virus.
Andes orthohantavirus (ANDV), a species of Orthohantavirus, is a major causative agent of hantavirus cardiopulmonary syndrome (HCPS) and hantavirus pulmonary syndrome (HPS) in South America. It is named for the Andes mountains of Chile and Argentina, where it was first discovered. Originating in the reservoir of rodents, Andes orthohantavirus is easily transmitted to humans who come into contact with infected rodents or their fecal droppings. However, infected rodents do not appear ill, so there is no readily apparent indicator to determine whether the rodent is infected or not. Additionally, Andes orthohantavirus, specifically, is the only hantavirus that can be spread by human to human contact via bodily fluids or long-term contact from one infected individual to a healthy person.
A robovirus is a zoonotic virus that is transmitted by a rodent vector.
Caño Delgadito orthohantavirus (CADV) is a hantavirus present in Venezuela. Its natural reservoir is Alston's cotton rat. Transmission among cotton rats appears to be horizontal. While human disease caused by CADV has not yet been identified, it has been isolated from oropharyngeal swabs and urine of infected cotton rats, indicating that it may be infectious to humans in the same manner as other hantaviruses, via inhalation of aerosolized droplets of saliva, respiratory secretions, or urine. CADV was discovered in the 1990s from rodent species in the Llanos in Venezuela.
Hantavirus hemorrhagic fever with renal syndrome (HFRS) is a group of clinically similar illnesses caused by species of hantaviruses. It is also known as Korean hemorrhagic fever and epidemic hemorrhagic fever. It is found in Europe, Asia, and Africa. The species that cause HFRS include Hantaan orthohantavirus, Dobrava-Belgrade orthohantavirus, Saaremaa virus, Seoul orthohantavirus, Puumala orthohantavirus and other orthohantaviruses. Of these species, Hantaan River virus and Dobrava-Belgrade virus cause the most severe form of the syndrome and have the highest morbidity rates. When caused by the Puumala virus, it is also called nephropathia epidemica. This infection is known as sorkfeber in Swedish, myyräkuume in Finnish, and musepest in Norwegian.
Hantavirus pulmonary syndrome (HPS) is one of two potentially fatal syndromes of zoonotic origin caused by species of hantavirus. These include Black Creek Canal virus (BCCV), New York orthohantavirus (NYV), Monongahela virus (MGLV), Sin Nombre orthohantavirus (SNV), and certain other members of hantavirus genera that are native to the United States and Canada.
Soochong virus (SOOV) is a zoonotic negative sense single-stranded RNA virus. It may be a member of the genus Orthohantavirus, but it has not be definitively classified as a species and may only be a strain. It is one of four rodent-borne Hantaviruses found in the Republic of Korea. It is the etiologic agent for Hantavirus hemorrhagic fever with renal syndrome (HFRS). The other species responsible for HFRS in Korea are Seoul virus, Haantan virus, and Muju virus.
Prospect Hill orthohantavirus is a single-stranded, negative-sense Hantaan-like zoonotic RNA virus isolated from meadow voles and microtine and other cricetid rodents in the United States. It has a widespread distribution in Pennsylvania, Maryland, West Virginia, Minnesota and California. The overall risk of infection in humans is low. It was first isolated from a meadow vole found in Prospect Hill, Maryland for which it is named.
Monongahela virus (MGLV) is a single-stranded, negative-sense Orthohantavirus virus of zoonotic origin that causes hantavirus pulmonary syndrome.
Choclo orthohantavirus (CHOV) is a single-stranded, negative-sense RNA zoonotic New World hantavirus. It was first isolated in 1999 in western Panama. The finding marked the first time Hantavirus pulmonary syndrome (HPS) was found in Central America.
Nova virus is a single-stranded, negative-sense, enveloped RNA virus with a trisegmented genome. It belongs to one of the most divergent lineages of the hantavirus group, which consists of zoonotic viruses belonging to the family Bunyaviridae. As of now, no human cases of infection have been reported.
Bloodland Lake virus (BLLV) is a single-stranded, negative-sense RNA virus of New World Orthohantavirus first isolated in a Prairie vole near Bloodland Lake, Fort Leonard Wood, Pulaski County, Missouri in 1994. BLLV has also been isolated in Prairie voles in St. Louis County, Missouri.
Climate change in the United States Virgin Islands encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. territory of the United States Virgin Islands. The United States Environmental Protection Agency (EPA) has noted a variety of expected consequences of this phenomenon.
Disease ecology is a sub-discipline of ecology concerned with the mechanisms, patterns, and effects of host-pathogen interactions, particularly those of infectious diseases. For example, it examines how parasites spread through and influence wildlife populations and communities. By studying the flow of diseases within the natural environment, scientists seek to better understand how changes within our environment can shape how pathogens, and other diseases, travel. Therefore, diseases ecology seeks to understand the links between ecological interactions and disease evolution. New emerging and re-emerging infectious diseases are increasing at unprecedented rates which can have lasting impacts on public health, ecosystem health, and biodiversity.
Global climate change has increased the occurrence of some infectious diseases. Infectious diseases whose transmission is impacted by climate change include, for example, vector-borne diseases like dengue fever, malaria, tick-borne diseases, leishmaniasis, zika fever, chikungunya and Ebola. One mechanism contributing to increased disease transmission is that climate change is altering the geographic range and seasonality of the insects that can carry the diseases. Scientists stated a clear observation in 2022: "The occurrence of climate-related food-borne and waterborne diseases has increased ."
1 2 3 Janet (2014-01-04). "Rats & Mice After Storms - PEST UK". PEST UK - We provide pest control services to both domestic & commercial premises. Retrieved 2024-11-19.
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