Hantavirus alert: Deer mice, rice rats, and other rodents linked to hantavirus outbreak worldwide

The latest hantavirus infections made the disease hit the headlines all over the globe. In particular, health authorities claim that they had monitored the infections related to travellers and isolated expedition paths that took place during the cruise trip across the South Atlantic Ocean, including territories close to Antarctica.The infection can be caused by a small amount of aerosolised urine or droppings of infected rats and mice, which often leads to pulmonary syndrome, renal failure, or other complications. Researchers claim that there are many natural rodent hosts to hantaviruses, where each hantavirus strain is associated with one particular rodent species. The list includes deer mice from North America, rice rats that occur in the wetlands of the Gulf Coast region, and other rodents.The deer mouse is considered the primary carrier responsible for most cases of hantavirus pulmonary syndrome (HPS) in the United States and Canada. This small rodent is widespread across western and central North America and is easily recognised by its brown or grey body with a white underside and feet, as reported by the Centers for Disease Control and Prevention (CDC).Scientists identified the connection between deer mice and hantavirus after the major 1993 outbreak in the Four Corners region of the United States. That outbreak revealed a previously unknown disease causing sudden respiratory collapse in otherwise healthy adults. The virus remains the dominant hantavirus strain in North America. Deer mice commonly inhabit rural cabins, sheds, woodpiles, barns, and storage areas, especially where food and shelter are available. Because these rodents often enter homes during colder months, human exposure risk increases significantly in autumn and winter.Another important carrier of hantaviruses in North America is the white-footed mouse, or the wood mouse. This rodent is found widely throughout the northeastern areas of the United States and certain areas of Canada. Its common name, white-footed mouse, is derived from the characteristic white feet that contrast sharply with its greyish or brown fur.These nocturnal mice are timid and avoid human contact. In their natural habitat, white-footed mice build nests under fallen logs, rocks, bushes, hollow trees, and abandoned burrows. However, they tend to find refuge indoors during cold periods, inhabiting attics, garages, crawl spaces, basements, and even wall cavities.According to Canadian government reports, their feces, urine, nesting material, and hair may become airborne when disturbed.Among the significant findings regarding hantaviruses, one of the most vital discoveries was associated with the marsh rice rat species, scientifically named Oryzomys palustris. The marsh rice rat is a semi-aquatic rodent species that resides in marshes, wetlands, and coastal habitats located in the southern United States, specifically on the Gulf Coast.As reported by the National Library of Medicine, in the article ‘Bayou Hantavirus Cardiopulmonary Syndrome, Louisiana, USA, 2022–2023’ and the Centers for Disease Control and Prevention (CDC), the scientists discovered rice rats to be the main hosts of the Bayou virus, which is a hantavirus strain that causes hantavirus pulmonary syndrome in both Texas and Louisiana.According to various reports and research, cotton rats are another rodent species associated with hantavirus infections in the United States. The species has been linked to the Black Creek Canal virus, identified in southern Florida.Although confirmed human infections involving cotton rat-associated hantaviruses are relatively rare compared to deer mouse infections, the discovery highlighted how multiple rodent species across different ecosystems can maintain distinct hantavirus strains.The Deer mouse is small, with a brown or grey back, a white belly, and distinct white feet. Its tail is usually two-toned, darker on top and lighter underneath. It also has large eyes and relatively big ears compared to its body size.It is commonly found in rural and natural environments such as forests, grasslands, cabins, barns, sheds, and woodpiles. It often enters human structures during colder months in search of food and shelter.The White-footed mouse has reddish-brown or grey-brown fur with bright white feet and a white underside. It has large ears and eyes, and a long tail that is slightly darker above and lighter below.It is commonly found in wooded areas, brushy regions, and forest edges. It may also move into homes, garages, attics, and basements during winter or cold weather conditions.The Marsh rice rat has coarse brown fur, smaller eyes, and partially webbed hind feet. Its body is adapted for wet environments, and it often appears more robust than typical mice.It is commonly found in marshes, wetlands, coastal grasslands, and swampy areas, especially in the southeastern United States and along the Gulf Coast.The Cotton rat is larger than most mice, with a stocky body, coarse grey-brown fur, small ears, and a relatively short tail. Its coat often looks rough or bristly.It is commonly found in overgrown fields, agricultural land, roadside vegetation, and grassy areas, mainly in the southern United States.Common house rats like the Norway rat and Black rat live in cities, sewers, and buildings, adapting closely to humans. Hantavirus-linked rodents such as deer mice and rice rats are wild species found in forests, fields, and wetlands, becoming risky mainly when humans enter their contaminated environments.Indirect transmission of hantaviruses occurs more frequently than does infection resulting from direct contact with rodents. Inhalation of airborne particles is the primary route of exposure to hantaviruses.Once dried urine or feces from rodents are disturbed, the disease-causing particles become airborne, increasing the risk of contamination significantly. Exposure to an indoor environment infested by rodents that has not been used for a prolonged period of time is highly dangerous.