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Filoviral Infections - Clinical Manifestations, Causes, Transmission, Diagnosis, and Management

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Filoviruses can cause serious illness that has a high morbidity and fatality rate. Read the article to learn more about filoviral infections.

Written by

Dr. Vennela. T

Medically reviewed by

Dr. Kaushal Bhavsar

Published At August 14, 2023
Reviewed AtAugust 17, 2023


Filoviruses can bring on hemorrhagic fever members of the viral family Filoviridae. Cuevavirus, Marburgvirus, and Ebolavirus are the three genera of filoviruses that are currently recognized. The six species that result from this additional subdivision are Zaire, Sudan, Tai Forest, Bundibugyo, Reston, and Bombali. The Reston and Bombali strains have not been linked to human illnesses. The name ‘filovirus’ comes from the Latin word ‘filum,’ which means ‘thread,’ and refers to viruses that are structurally filamentous and frequently have a stringlike or torus-like appearance. They possess enclosed particles with a linearly organized negative-sense single-stranded RNA genome.

Additionally, they have four structural proteins, including the virus-encoded polymerase, and a single glycoprotein spike on their surface. Human-to-human interaction facilitates the rapid spread of the highly dangerous filovirus. They are considered level 4 biosafety agents and have incredibly high death rates.

What Are the Clinical Manifestations of Filovirus Infections?

Both humans and non-human primates can contract a severe hemorrhagic fever from a filovirus. The symptoms often start 2 to 21 days after contact (on average 8 to 10) and are frequently confused with the flu or malaria. Between 30 and 50 percent of patients experience hemorrhagic symptoms, which often involve mucosal bleeding, especially in the gastrointestinal and genitourinary tracts. The symptoms of filovirus infections are

  • Anorexia.

  • Fever.

  • Chills.

  • Headache.

  • Myalgia.

  • Abdominal pain.

  • A sore throat.

  • Nausea.

  • Vomiting.

  • Coughing.

  • Arthralgia.

  • Diarrhea.

  • Pharyngeal and conjunctival vasodilation.

  • The patients are dehydrated, uninterested, and confused. A distinctive, nonpruritic, maculopapular centripetal rash with variable degrees of erythema may appear on them; by day five or seven of the sickness, this rash usually desquamates. At the worst of the illness, hemorrhagic signs appear and have prognostic significance. The most common type of bleeding, aside from petechia and hemorrhages from puncture wounds and mucosal membranes, is bleeding into the gastrointestinal tract.

What Happens in Filovirus Infection?

The virus affects cells like macrophages and dendritic cells after entering the body through mucosal membranes. Following their necrosis and the consequent release of thousands of fresh viral particles into the body, the filovirus replicates within. Through the inhibition of the Type-I interferon response, the virus then quickly spreads throughout the body. The virus spreads through systemic transmission to the lymph nodes, spleen, liver, thymus, and other immunologic tissue. The necrosis of tissues in organs like the liver and spleen is a common symptom of the deadly disease. As a result of a systemic inflammatory reaction brought on by the filovirus infection, the body can experience shock, nausea, vomiting, vascular leak, coagulation issues, and volume depletion symptoms.

How Does Filoviral Infection Spread?

Filoviruses are zoonotic, which means they can spread from people to animals. The African fruit bat is the host of the Marburg virus reservoir, but additional research is required to establish whether other species could also act as hosts. Even though bats are indeed implicated and could serve as the reservoir, scientists have not yet identified the Ebola virus' host. Filoviruses may enter human populations due to various factors, including population increase, the encroachment of forested regions, and direct contact with wildlife (such as eating bushmeat). Once a person has become infected, filoviruses can be transferred from one person to another by contacting their bodily fluids. Caretakers and medical professionals who do not wear the proper personal protective equipment (PPE) are most at risk of contracting an infection.

What Are the Laboratory Findings of Filoviral Infections?

Leukopenia (as low as 1000/l), left shift with atypical lymphocytes, thrombocytopenia (50,000–100,000/l), markedly elevated serum transaminase levels (typically AST [aspartate transaminase] exceeding ALT [alanine transaminase]), hyperproteinemia, and proteinuria are associated with the disease even though laboratory parameters are less distinctive. In addition, there are noticeable fibrin split products and delayed prothrombin and partial thromboplastin times. A subsequent bacterial infection may cause increased white blood counts at a later stage. Patients who eventually recover have a fever for five to nine days.

How Is the Filoviral Infection Diagnosed?

General lab tests will often show evidence of intravascular volume depletion from gastrointestinal fluid losses combined with significant liver and renal lab abnormalities in addition to the history and physical examination. For the diagnosis of filovirus infection, indirect identification of viral particles, proteins, or RNA (ribonucleic acid) from blood, serum, or plasma is performed, with RNA nucleic acid amplification testing being the preferred technique. These tests carry a high risk of lab-acquired illnesses, and patient samples provide a very high biohazard risk, necessitating particular laboratory techniques. Only virus isolation can provide definite proof of infection. IgM (immunoglobulin-M) testing can be diagnostic during the recovery stage of disease, although IgG is typically just tracked for epidemiologic surveillance.

How Is Filoviral Infection Managed?

While new management options are beginning to emerge, managing filovirus disease typically centers on prevention or detection and supportive care. Supportive care, including hydration and electrolyte supplementation, respiratory support, and antibiotic medication, is the mainstay of treatment for filoviral infection.

  • Sanitary Prophylaxis

    • When handling infected tissues or contaminated objects or cleaning polluted locations, always wear personal protective equipment (PPE).

      • Gloves (+/- puncture-resistant), a face shield, goggles, and a gown that can withstand water.

    • Use proper handwashing techniques to get dirt, blood, and other substances off the skin. Use hand sanitizers with alcohol as a second step or a 0.05 percent chlorine solution.

    • As much as possible, limit any contaminated garbage to the area surrounding the source.

    • Necropsies of dead bodies are considered high-risk procedures that call for the employment of a variety of protective equipment, such as face shields, impermeable gear, and personal air filtration devices. Make use of disposable tools.

      • It is strongly advised that those doing this job receive the necessary instruction in safe working practices and good technique.

    • Where filoviruses are prevalent, use the appropriate PPE before handling bats or their excrement.

  • Medical Prophylaxis

    • Humans use experimental Ebola virus vaccines under ‘compassionate use’ or ‘extended access’ conditions.

    • A vesicular stomatitis virus vector is used to create a recombinant MARV vaccine.

    • There is no medical prophylactic for LLOV (Lloviu virus) at the moment.

    • After a clinical illness has subsided, milk and semen may still contain viruses; therefore, secretions should be examined before applying relevant swine or NHP husbandry techniques.

What Are the Complications of Filovirus Infection?

When the disease is severe, death usually happens 6 to 16 days after the first symptoms appear. Usually, shock and multiorgan failure, especially hepatic and renal failure, as well as thrombocytopenia and coagulopathy, are the causes of death.


In conclusion, filoviral infections are a class of extremely virulent and frequently fatal diseases brought on by filoviruses like the Marburg and Ebola viruses. These viruses have sometimes created outbreaks, mostly in Africa, which have posed serious public health issues. The fact that they can cause severe hemorrhagic fever with high fatality rates highlights the critical need for strong containment measures, comprehensive surveillance, early detection, and continued research into therapies and vaccines. While there has been progress in the understanding of the biology of filoviruses and the creation of certain experimental therapies, it is still crucial that governments, researchers, and global health organizations continue to work together to protect the public's health and lessen the effects of upcoming outbreaks.

Dr. Kaushal Bhavsar
Dr. Kaushal Bhavsar

Pulmonology (Asthma Doctors)


viral infectionfiloviral infections
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