Arenaviral haemorrhagic fever

Arenaviral haemorrhagic fevers are acute viral illnesses caused by arenaviruses, which are bi- or trisegmented ambisense RNA viruses belonging to the family Arenaviridae. The name derives from the Latin 'arena' meaning sand, referring to the characteristic grainy appearance of virions under electron microscopy caused by host ribosomes incorporated into the viral particle. These viruses maintain persistent infections in rodent reservoirs and occasionally spill over to humans, causing disease syndromes that range from mild febrile illness to severe haemorrhagic fever with high mortality in some cases.

Clinical presentation of arenaviral haemorrhagic fevers typically begins with nonspecific febrile symptoms including fever, malaise, headache, and myalgia, which may progress to more severe manifestations involving multiple organ systems. Haemorrhagic features can include mucosal bleeding, petechiae, and evidence of vascular permeability. Some arenaviruses, such as lymphocytic choriomeningitis virus, can cause aseptic meningitis characterized by inflammation of the brain and spinal cord membranes. The severity spectrum varies considerably among the different arenavirus species, with some causing relatively mild disease while others are associated with case fatality rates exceeding 30 percent in untreated cases.

Arenaviruses exhibit a distinct geographic distribution pattern, with New World species primarily found in the Latin America-Caribbean region and Old World species concentrated in parts of Africa, particularly where Lassa fever is endemic. Phylogenetic analyses suggest that New World arenaviruses evolved between 41,400 and 3,300 years ago, while Old World species diverged approximately 23,100 to 1,880 years ago, most likely in southern Africa. The epidemiological association with rodents has led to the designation of some arenaviruses as roboviruses, reflecting their rodent-borne nature. At least eight arenaviruses are confirmed human pathogens, with additional novel viruses likely remaining undiscovered in rodent populations worldwide.

Human infection primarily occurs through direct contact with infected rodent reservoirs or exposure to their excreta, including urine, saliva, and droppings. Transmission routes may include inhalation of aerosolized viral particles, percutaneous inoculation through contaminated objects, or direct contact with broken skin and mucous membranes. Person-to-person transmission can occur, particularly in healthcare settings through contact with infectious body fluids, necessitating strict barrier precautions. The zoonotic nature of these infections means that human cases typically occur in individuals with occupational or residential exposure to rodent-infested environments.

Individuals with frequent or intensive exposure to rodent reservoirs face elevated risk of infection, including agricultural workers, pest control personnel, and residents of dwellings with significant rodent infestations in endemic areas. Laboratory workers handling arenavirus specimens or conducting research with these pathogens are at occupational risk and require appropriate biosafety measures. Healthcare workers providing care to infected patients without adequate protective measures may acquire infection through contact with infectious body fluids. Persons residing in or traveling to regions where known human-pathogenic arenaviruses are endemic, particularly without precautions to minimize rodent contact, constitute the primary at-risk population for spillover infection.

Prevention strategies focus on rodent control measures to reduce contact with reservoir species, including sealing dwellings, proper food storage, and safe cleanup of rodent infestations to minimize exposure to contaminated materials. Healthcare workers should implement standard and transmission-based precautions when caring for suspected or confirmed cases, including appropriate personal protective equipment and safe injection practices. No widely available human vaccine exists for most arenaviruses, though experimental vaccine approaches have shown promise for certain high-risk pathogens. Public health education in endemic areas should emphasize avoidance of rodent contact and safe handling practices for potentially contaminated materials.

Surveillance for arenaviral haemorrhagic fevers requires integration of human case reporting with rodent reservoir monitoring, as animal population dynamics often predict human outbreak risk. Laboratory confirmation typically relies on molecular detection of viral RNA, virus isolation in appropriate biosafety containment, or serological identification of virus-specific antibodies. The nonspecific early clinical presentation poses diagnostic challenges, making epidemiological context including geographic exposure and rodent contact history essential for case identification. Reporting requirements vary by jurisdiction, but suspected cases of viral haemorrhagic fever generally warrant immediate notification to public health authorities given the potential for severe outcomes and healthcare-associated transmission.

1. 1 Wikidata. Arenaviral haemorrhagic fevers.
2. 2 Wikipedia. Arenavirus - Wikipedia.

ICD-10

A96

ICD-11

Total cases

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