What is Viral Hemorrhagic Fevers?
Viral hemorrhagic fevers, or VHFs, are severe illnesses that cause fevers and are caused by four types of viruses: Arenaviridae, Bunyaviridae, Filoviridae, and Flaviviridae. These viruses, which are known for triggering a wide variety of symptoms—including blood clotting disorders, unstable blood pressure, changes in mental state, and potentially, death. The severity of illnesses caused by these viruses can vary greatly, with some causing mild sickness while others can be fatal.
Most of the viruses that cause these diseases are transmitted to humans through vectors, typically bugs or rodents. Due to the nature of transmission, these diseases are usually confined to regions where the carriers thrive. But, with the rise in global movement and growing connectivity, these diseases have started to emerge outside of their original areas. So, this piece aims to shed light on viral hemorrhagic fevers, placing special emphasis on the strains that carry the highest death rates.
What Causes Viral Hemorrhagic Fevers?
Various viruses are known to cause diseases known as viral hemorrhagic fevers. These viruses belong to different families:
Arenaviridae family:
* Chapare virus causes Chapare hemorrhagic fever.
* Guanarito virus leads to Venezuelan hemorrhagic fever.
* Junin virus causes Argentine hemorrhagic fever.
* Lassa virus results in Lassa fever.
* Lujo virus leads to Lujo hemorrhagic fever.
* Lymphocytic choriomeningitis virus causes a disease called Lymphocytic choriomeningitis.
* Machupo virus results in Bolivian hemorrhagic fever.
* Sabia virus causes Brazilian hemorrhagic fever.
Bunyaviridae family:
* Crimean-Congo hemorrhagic virus is responsible for Crimean-Congo hemorrhagic fever.
* Dobrava-Belgrade virus leads to Hemorrhagic fever with renal syndrome.
* Hantaan virus also causes Hemorrhagic fever with renal syndrome.
* Puumalavirus is another virus that results in Hemorrhagic fever with renal syndrome.
* Rift Valley fever virus causes Rift Valley fever.
* Saaremaa virus leads to Hemorrhagic fever with renal syndrome.
* Seoul virus causes Hemorrhagic fever with renal syndrome.
* Sin Nombre virus results in Hantavirus pulmonary syndrome.
* Severe fever and thrombocytopenia syndrome virus causes Severe fever and thrombocytopenia syndrome.
* Tula virus also leads to Hemorrhagic fever with renal syndrome.
Filoviridae family:
* Bundibugyo ebolavirus is responsible for Ebola virus disease.
* Marburg virus leads to Marburg hemorrhagic fever.
* Sudan ebolavirus also causes Ebola virus disease.
* Taï Forest ebolavirus causes Ebola virus disease, too.
* Zaire ebolavirus, just like the three above, also results in Ebola virus disease.
Flaviviridae family:
* Dengue virus is responsible for Dengue fever.
* Kyasanur forest disease virus causes Kyasanur forest disease.
* Omsk hemorrhagic fever virus leads to Omsk hemorrhagic fever.
* Yellow fever virus results in Yellow fever.
Risk Factors and Frequency for Viral Hemorrhagic Fevers
Viruses from the Arenaviridae family are connected to diseases found in rodents and are divided into two groups: New World and Old World. These viruses are linked to rodents found in Africa, America, Asia, and Europe. People can get infected through contact with rodent urine or droppings. Also, when rodent droppings get disturbed and airborne, people can breathe in these virus-laden particles. Some of these viruses can also spread from person to person or in healthcare settings. The Lassa virus, a type of arenavirus, has resulted in massive outbreaks in West Africa, with up to half of those affected dying from the disease. This virus spreads mainly through direct contact with multimammate rats, but can also be caught when these rodents are captured to be eaten.
Bunyaviruses, usually spread via insects and rodents, can cause a range of illnesses from mild to severe. These diseases include Crimean-Congo hemorrhagic fever, hantavirus infections, and Rift Valley fever. The Crimean-Congo hemorrhagic fever is especially important to know about because it’s the most common tick-induced illness in humans. A certain type of bunyavirus, the Nairovirus, causes this disease. People can get infected either from ticks or through exposure to blood or body fluids. This disease leads to serious infection with a high risk of death.
Filoviruses cause diseases such as Ebola and Marburg hemorrhagic fever, and have been found in bats in Africa. Once a human gets infected, the disease can spread to other people, especially those who are taking care of the infected patient. There have been many Ebola outbreaks in the Democratic Republic of Congo, with a very high death rate of 80 to 90%. Marburg hemorrhagic fever also has a very high death rate of up to 82% in low-income countries.
Flaviviruses can cause various diseases and are usually spread via insects. The Dengue virus, which is a type of flavivirus, is spread by Aedes aegypti or Aedes albopictus mosquitoes. Depending on the severity, the resulting disease is categorized into three types: dengue without warning signs, dengue with warning signs, and severe dengue. Dengue is found in over 100 countries across Africa, the Americas, Asia, Australia, Europe, and the Pacific Islands. Dengue fever’s death rate ranges from 0.8% to 2.5%, but the risk of severe illness and death increases with dengue hemorrhagic fever and dengue shock syndrome.
Signs and Symptoms of Viral Hemorrhagic Fevers
Patients suffering from Viral Hemorrhagic Fevers (VHFs) can exhibit general signs like feeling unwell, headaches, and fevers. They may also experience more specific symptoms such as pain behind the eyes, joint pains, red eyes, stomach ache, vomiting, and diarrhea. Some individuals may also encounter issues like bleeding gums or nosebleeds. On physical examination, small red or purple spots caused by bleeding into the skin, known as petechiae, may be noticed.
- General unease
- Headaches
- Fever
- Pain behind the eyes
- Joint pains
- Red eyes
- Stomach ache
- Vomiting
- Diarrhea
- Bleeding gums or nosebleeds
- Petechiae (small red or purple spots caused by bleeding into the skin)
Testing for Viral Hemorrhagic Fevers
If your doctor suspects you have viral hemorrhagic fever, a serious condition that causes bleeding and other symptoms, they’ll run several tests. This includes a complete blood count to check the number and types of cells in your blood, a comprehensive metabolic panel to assess your overall health and organ function, and a type and cross test to match your blood type in case you need a transfusion. They’ll also look at how your blood clots and how well your liver is working.
The doctor will also want to rule out a bacterial infection, so you might have tests on your urine, including a urinalysis and a urine culture. They may take a sample of your blood to grow in a lab to see if bacteria are present, and you’ll probably have a chest X-ray to check for infection in your lungs.
Another test that can be done is serological testing. This checks for specific antibodies, substances your immune system makes in response to the virus, in your blood. This test can be helpful, but it is not the most reliable as some people may not produce enough antibodies to be detected, or it may detect the wrong kind of antibodies.
Two more accurate methods are reverse transcriptase-polymerase chain reaction (RT-PCR) and virus isolation via cell culture. The RT-PCR test detects the genetic material of the virus in your body which can confirm the presence of the virus. Virus isolation, on the other hand, is done by taking a sample from you and trying to grow the virus in a lab. If the virus grows, it confirms you have the infection.
Treatment Options for Viral Hemorrhagic Fevers
When someone is suspected to have viral hemorrhagic fever, proper management is vital to increase survival chances and prevent possible infections from spreading to others. Viral hemorrhagic fever family of diseases have severe symptoms and can be contracted via travel. People showing symptoms should be separated from others, and the staff looking after them should wear protective gear for their safety. Current treatment options focus primarily on supportive care, meaning the goal of treatment is to help the body recover on its own. There is ongoing research to find more effective treatments for such illnesses.
For example, if a patient is suspected to have Lassa virus, the drug Ribavirin could likely improve their condition if given early in the disease’s course. However, experimental trials are limited. New medical treatments like Favipiravir and LASV-specific monoclonal antibodies are being investigated. Unfortunately, no successful vaccine for Lassa fever has been discovered yet.
Crimean-Congo hemorrhagic fever is another disease requiring attention. The main treatment options for this are support and care. The drug Ribavirin has shown some potential effects against this virus in the laboratory environment though it’s not an established treatment option. As of now, no effective vaccine for humans exists. It’s advised that people who work with animals or are in agriculture should use bug spray and avoid making direct contact with the blood or other body fluids of potentially infected animals or humans.
Regarding Ebola virus disease and Marburg hemorrhagic fever, these also demand attentive care. There aren’t any vaccines available for the Marburg virus at the moment. For the Ebola virus, one vaccine has been approved by the Food and Drug Administration, but it only protects against one specific type of ebolavirus, known as the Zaire ebolavirus.
As for Dengue fever, at present, there are no effective antiviral treatments available. So management involves supportive care. At least one Dengue fever vaccine exists, but it is only available in Latin America and Southeast Asia. Furthermore, the World Health Organization advises that this vaccine should only be given to individuals who have had dengue infection before.
What else can Viral Hemorrhagic Fevers be?
The following medical conditions can share similar symptoms and should be considered when diagnosing a patient:
- Acute Human Immunodeficiency Virus (HIV) infection
- Chikungunya virus
- Leptospirosis
- Malaria
- Malignancy
- Systemic Lupus Erythematosus
- Typhoid fever
What to expect with Viral Hemorrhagic Fevers
Viral hemorrhagic fevers include a broad range of illnesses, and because of this, how they progress can greatly differ. Many of these diseases can lead to widespread outbreaks and are often linked with high rates of sickness and death, primarily because we currently don’t have any specified treatments available. The death rate among diagnosed cases can reach up to 80%-90% in developing countries.
Possible Complications When Diagnosed with Viral Hemorrhagic Fevers
One of the most extreme outcomes of viral hemorrhagic fevers is the breakdown of multiple body systems, which can lead to death. The main approach to dealing with this illness is supportive care. Since there’s a danger of hospital-acquired infections and additional outbreaks, it’s crucial that isolation precautions for viral hemorrhagic fever be enforced promptly if this illness is suspected.
Common Severe Outcomes:
- Failure of multiple body systems
- Death
Management and Precautions:
- Supportive care
- Quick institution of isolation precautions if viral hemorrhagic fever is suspected
- Avoidance of hospital-acquired infections
- Prevention of additional outbreaks
Preventing Viral Hemorrhagic Fevers
Patients need to be aware of where these viruses are most common and take steps to prevent infection when travelling to areas where these diseases are common. The Centers for Disease Control, the World Health Organization, and the United States Department of State all offer helpful resources. These include up-to-date lists of areas currently experiencing outbreaks, as well as any travel alerts or restrictions.
