What Are Arenaviruses (Arenaviridae)?

Medically Reviewed by Dany Paul Baby, MD on October 04, 2022
Written by Sarah Vallie
4 min read

Many types of viruses can be spread by animals. These viruses can often make us very sick and even lead to death. Arenaviruses are one example. While some types of arenaviruses are mild, others can have long-lasting effects or be fatal.

Arenaviruses are viruses from the family Arenaviridae. They’re typically spread by rodents. Arenaviruses are zoonotic diseases, meaning they can be transmitted between people and animals.

Arenavirus transmission. Transmission of arenavirus often occurs when humans come into contact with the waste of an infected rodent. This can happen if someone eats food contaminated with rodent urine or feces or if broken skin comes into contact with rodent urine or feces. You can also get infected if you inhale particles contaminated with rodent excretions — for example, if you’re cleaning up rodent feces and inhale particles that are released into the air.

Some types of arenavirus diseases can be transmitted from person to person, but that's rare. One type of arenavirus disease called lymphocytic choriomeningitis (LCM) can be passed from mother to fetus. 

There are several diseases that can the arenavirus family can cause. Rodents all over the world can carry arenaviruses. To differentiate, arenaviruses are divided into “Old World” and “New World” viruses depending on where they are most often found. Old World viruses are typically found in the Eastern Hemisphere, while New World viruses are typically found in the Western Hemisphere.

Lymphocytic choriomeningitis. LCM is the only arenavirus disease that's found in both the Eastern and Western Hemispheres, though it's classified as an Old World virus. LCM was discovered in 1933 and was the first identified arenavirus. LCM is carried by the common house mouse. 

Other Old World viruses. Old World viruses typically occur in Africa, Europe, and Asia. These may include:

  • Lassa virus (LASV). Lassa virus is usually found in Southern Africa. It's spread by multimammate mice, a family group of mice endemic to Africa. Lassa virus causes Lassa fever.
  • Lujo virus. Lujo hemorrhagic fever is usually found in southern Africa. There's limited information on this virus, and the primary source of infection is currently unknown. Lujo virus causes Lujo hemorrhagic fever. 

New World viruses. New World viruses are found in North America and South America. They include:

  • Chapare virus. The Chapere virus has thus far only been found in Bolivia. There have only been two outbreaks of this virus. Chapare virus causes Chapare hemorrhagic fever.
  • Guanarito virus. Guanarito virus is endemic to Venezuela. It may be carried by Alston’s cotton rat (Sigmodon alstoni) or the short-tailed cane mouse (Zygodontomys brevicauda). Guanarito virus causes Venezuelan hemorrhagic fever.
  • Junin virus. Junin virus is mainly found in Argentina. It’s spread by the drylands vesper mouse (Calomis musculinus). Junin virus can cause Argentine hemorrhagic fever.
  • Machupo virus. Machupo virus is another type of arenavirus found in Bolivia. It’s carried by the large vesper mouse (Calomys callosus). Machupo virus can lead to Bolivian hemorrhagic fever.
  • Sabia virus. Sabia virus was discovered in Brazil. The host rodent is unknown. It can lead to Brazilian hemorrhagic fever.
  • Whitewater Arroyo virus. The Whitewater Arroyo virus has been found in the U.S. in New Mexico and California. It’s spread by the white-throated woodrat (Neotoma albigula). It can cause hemorrhagic fever.

Scientists discover new arenaviruses every few years. There are some arenaviruses that have been found in rodents but have not yet been found in humans.

The type of symptoms you experience from an arenavirus will depend on which arenavirus you become sick with.

Viral hemorrhagic fever. Many types of arenaviruses lead to hemorrhagic fever. Viral hemorrhagic fever can affect multiple organ systems. General symptoms of hemorrhagic fever include:

  • Fever
  • Achiness in the bones, joints, and muscles
  • Diarrhea
  • Dizziness
  • Fatigue
  • Nausea
  • Vomiting
  • Weakness

Hemorrhagic fever can also lead to:

  • Coma
  • Delirium
  • Internal bleeding and bleeding from the ears, eyes, or mouth
  • Kidney failure
  • Liver failure
  • Nervous system malfunction
  • Respiratory failure
  • Death

Different types of hemorrhagic fevers may have different or additional symptoms:

  • Argentine hemorrhagic fever may cause low platelets in the blood (thrombocytopenia), neurological disorders, and bleeding.
  • Brazilian hemorrhagic fever may cause hepatic necrosis, a condition in which hepatocytes, epithelial cells found in the liver, die.
  • Whitewater Arroyo virus may cause liver failure.

Lassa fever. About 80% of Lassa fever infections are mild. Mild symptoms may include:

  • Fever
  • General malaise
  • Headache
  • Weakness

More severe symptoms of Lassa fever may include: 

  • Hemorrhaging
  • Neurological problems
  • Pain in the abdomen, chest, and back
  • Respiratory distress
  • Shock
  • Vomiting
  • Death

Approximately one-third of Lassa fever infections lead to deafness.

Lymphocytic choriomeningitis. Lymphocytic choriomeningitis often causes neurological disease. Common symptoms include:

  • Fever
  • Headache
  • Loss of appetite
  • Malaise
  • Muscle aches
  • Nausea
  • Vomiting

In some cases, LHC can lead to meningitis, encephalitis, hydrocephalus, and myelitis. A baby who is infected while still in the womb may be born with birth defects. A miscarriage may occur if a pregnant person is infected in the first trimester. 

Most arenaviruses are detected via lab testing. 

The treatment used will depend on the type of arenavirus you have. Many arenaviruses can be treated with the antiviral drug Ribavirin.

Ribavirin doesn't work on lymphocytic choriomeningitis. The typical treatment for LCM is supportive treatment and, in some cases, anti-inflammatory drugs.

The key to preventing arenavirus infection is pest control. Avoid contact with wild mice and rodents. While it’s rare for pet rodents to contract arenavirus, you should still be careful when handling them. 

To avoid contracting arenaviruses, consider the following steps:

  • Seal up any rodent entry holes.
  • Trap and get rid of mice or rats.
  • Keep food in sealed and closed containers.
  • Use gloves and, if possible, a mask, when cleaning rodent-infested areas.
  • Don't vacuum or sweep up rodent-infested areas, as this may stir up infected dust. Instead, wet the contaminated area with bleach or a similar disinfectant and then use a damp towel to lift the contaminated material. Use a mop or sponge along with bleach or disinfectant to thoroughly clean the area.