Life-threatening viruses and what we should know about them

By Rinshi Ansari, February 25, 2023

Most deadliest viruses in the world are viruses that can cause severe illness and even death in humans. They can be transmitted through various means, such as contact with infected bodily fluids, inhalation of respiratory droplets, or exposure to contaminated surfaces.

Understanding life-threatening viruses are important because they can have significant impacts on public health, causing epidemics and pandemics that can affect millions of people worldwide. By understanding the nature of these viruses, we can take steps to prevent their spread, develop effective treatments and vaccines, and improve our ability to respond to outbreaks.

There are many different types of life-threatening viruses, each with its unique characteristics, modes of transmission, and clinical manifestations. Some viruses, like Ebola and Marburg viruses, can cause hemorrhagic fever, which can lead to internal bleeding and organ failure. Other viruses, like HIV and hepatitis B and C viruses, can cause chronic infections that can lead to long-term health complications like liver damage and cancer.

Influenza viruses can cause respiratory illness ranging from mild to severe, and SARS-CoV-2, the virus responsible for COVID-19, can cause a range of symptoms, from mild cold-like symptoms to severe respiratory illness and death.

To protect ourselves and others from life-threatening viruses, it’s important to practice good hygiene, such as frequent handwashing, wearing masks, and avoiding close contact with sick people. Vaccines and antiviral medications can also be effective in preventing and treating viral infections. Public health officials and researchers are constantly working to improve our understanding of these viruses and develop new treatments and prevention strategies to minimise their impact on global health.

Ebola virus

The Ebola virus is a highly infectious virus that can cause severe and often fatal illnesses in humans and non-human primates. The virus is named after the Ebola River in the Democratic Republic of the Congo, where the first outbreak of the disease occurred in 1976. Since then, there have been several outbreaks of the Ebola virus in various parts of Africa, with the most recent one occurring in the Democratic Republic of the Congo in 2021.

The Ebola virus belongs to the Filoviridae family and has five species, four of which can cause disease in humans: Zaire, Sudan, Bundibugyo, and Tai Forest. The Zaire species, which caused the first outbreak in 1976 and has since caused several others, is the most deadly, with a case fatality rate of up to 90%. The virus is transmitted to humans through contact with infected bodily fluids such as blood, sweat, saliva, vomit, urine, and faeces. It can also be transmitted through contact with objects contaminated with infected bodily fluids, such as needles and syringes.

The incubation period of the virus ranges from 2 to 21 days, with an average of 8-10 days. The initial symptoms of the disease are similar to those of the flu and include fever, headache, muscle pain, and fatigue. As the disease progresses, it can cause vomiting, diarrhoea, abdominal pain, and haemorrhaging (bleeding) from the mouth, nose, and eyes. In severe cases, the disease can lead to organ failure and death.

There is no specific treatment for the Ebola virus, and supportive care is the mainstay of treatment. This includes fluid and electrolyte replacement, oxygen therapy, and treatment of complications such as bacterial infections. Experimental treatments, such as monoclonal antibodies, are being tested but are not yet widely available. Vaccines have been developed and used during outbreaks, but they are not yet licensed for general use.

Prevention of Ebola virus infection involves avoiding contact with infected bodily fluids and practising good infection control practices, such as using protective equipment like gloves, masks, and goggles and disinfecting surfaces and equipment. Public health measures such as early detection, isolation of infected individuals, and contact tracing are also important in controlling outbreaks.

The Ebola virus is one of the most deadliest viruses in the world that can cause severe illness and death in humans. While there is no specific treatment, supportive care can be effective in managing symptoms, and preventative measures such as infection control practices and vaccination can help prevent the spread of the disease.


HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, which is responsible for protecting the body from infections and diseases. HIV can be transmitted through contact with infected bodily fluids such as blood, semen, vaginal fluids, and breast milk. This can occur through unprotected sex, sharing needles or syringes, or from mother to child during pregnancy, childbirth, or breastfeeding.

Once the virus enters the body, it attacks and destroys a specific type of white blood cell called CD4+ T cells. These cells play a critical role in the immune system by fighting off infections and diseases. As the virus replicates and destroys more CD4+ T cells, the immune system becomes weakened and less able to fight off infections and diseases. This can lead to a condition known as acquired immunodeficiency syndrome (AIDS), which is the most advanced stage of HIV infection.

The symptoms of HIV can vary depending on the stage of the infection. In the early stages, a person may experience flu-like symptoms such as fever, headache, fatigue, and swollen lymph nodes. However, some people may not experience any symptoms at all. In the later stages, as the immune system becomes more damaged, a person may experience a range of infections and diseases, such as pneumonia, tuberculosis, and certain types of cancer.

While there is no cure for HIV, antiretroviral therapy (ART) can be highly effective in slowing down the progression of the disease and improving the quality of life for people living with HIV. ART involves taking a combination of medications that target different stages of the virus’s life cycle. These medications can reduce the amount of virus in the body, prevent the virus from replicating, and help to restore the immune system.

Prevention of HIV involves a range of strategies, including practising safe sex by using condoms and limiting the number of sexual partners, avoiding sharing needles or other injection equipment, and getting tested and treated for other sexually transmitted infections. Pre-exposure prophylaxis (PrEP) is a medication that can be taken by people at high risk of HIV infection to prevent them from becoming infected. Additionally, post-exposure prophylaxis (PEP) is a medication that can be taken after potential exposure to HIV to reduce the risk of infection.

In conclusion, HIV is one of the most deadliest viruses in the world that attacks the immune system and can lead to AIDS if left untreated. While there is no cure, antiretroviral therapy can be highly effective in managing the disease. Prevention strategies such as safe sex practices, PrEP, and PEP can help reduce the risk of infection. It is important for anyone who may be at risk of HIV to get tested and seek treatment if necessary.

Influenza virus

The influenza virus, commonly known as the flu, is a highly contagious virus that infects the respiratory system, including the nose, throat, and lungs. The virus can cause mild to severe illness, and in some cases, it can be life-threatening. Influenza is a seasonal virus that typically circulates during the fall and winter months in temperate climates.

Influenza viruses belong to the Orthomyxoviridae family. There are three main types of influenza viruses: A, B, and C. Influenza A viruses are responsible for most seasonal flu outbreaks and are also responsible for pandemics. Influenza B viruses are less common than influenza A viruses and are responsible for smaller outbreaks. Influenza C viruses cause mild respiratory illness but are not typically associated with outbreaks or epidemics.

The symptoms of influenza can vary but typically include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. In severe cases, influenza can lead to complications such as pneumonia, respiratory failure, and death. Certain groups of people are at higher risk of developing severe illness from influenza, including young children, older adults, pregnant women, and people with certain underlying medical conditions.

The flu is spread from person to person through respiratory droplets that are produced when an infected person talks, coughs, or sneezes. The virus can also be spread by touching a surface contaminated with the virus and then touching one’s mouth, nose, or eyes. The virus can be prevented through vaccination, which is recommended for everyone six months and older.

Antiviral medications can be effective in treating influenza if started early in the course of the illness. These medications work by blocking the replication of the virus in the body, and they can help reduce the severity and duration of symptoms, as well as the risk of complications. Other treatments for influenza include rest, hydration, and over-the-counter medications to manage symptoms.

In addition to vaccination, other preventive measures for influenza include frequent hand washing, avoiding close contact with sick people, covering one’s mouth and nose when coughing or sneezing, and staying home when sick to avoid spreading the virus to others.

To sum it up, the influenza virus is a highly contagious and most deadliest viruses in the world that infects the respiratory system and can cause mild to severe illness, particularly in high-risk groups. Vaccination, antiviral medications, and preventive measures such as frequent hand washing and staying home when sick can help reduce the spread of the virus and prevent severe illness.


SARS-CoV-2 is a novel coronavirus that belongs to the family Coronaviridae, a group of enveloped, positive-sense single-stranded RNA viruses. The virus is the causative agent of the ongoing COVID-19 pandemic, which started in late 2019 and has spread rapidly worldwide. The virus has a spherical or pleomorphic shape with an average diameter of 125 nm.

SARS-CoV-2 is composed of four main structural proteins: the spike (S) protein, the envelope (E) protein, the membrane (M) protein, and the nucleocapsid (N) protein. The S protein is responsible for mediating the virus’s entry into host cells and is the primary target for many COVID-19 vaccines. The E protein plays a role in virus assembly and release, while the M protein provides the structural framework for the virus. The N protein binds to the viral RNA and is involved in virus replication and transcription.

The virus has a lipid envelope derived from the host cell membrane, which contains viral proteins and glycoproteins. The envelope is studded with spike-like projections that give the virus its characteristic crown-like appearance, hence the name “coronavirus.” These spikes are made up of S proteins that bind to the host cell’s ACE2 receptor to facilitate entry into the cell.

SARS-CoV-2 has a relatively long incubation period of up to 14 days and can be transmitted through respiratory droplets or close contact with an infected person. The virus primarily targets the respiratory system, causing symptoms that range from mild, flu-like symptoms to severe respiratory illness, such as pneumonia and acute respiratory distress syndrome (ARDS). Other symptoms may include fever, cough, fatigue, loss of smell or taste, and gastrointestinal symptoms.

The virus’s genome is approximately 30 kilobases in length and encodes for a range of non-structural proteins and accessory proteins that contribute to the virus’s replication and immune evasion strategies. The virus also undergoes mutations, which can lead to the emergence of new variants with different transmission and virulence characteristics.

Overall, SARS-CoV-2 is one of the most deadliest viruses in the world that has caused a significant global health crisis. Extensive research is ongoing to understand better the virus’s pathogenesis, transmission, and immunity and to develop effective treatments and vaccines.

Hepatitis B and C viruses

Hepatitis B Virus (HBV):

Hepatitis B virus (HBV) is a double-stranded DNA virus that is transmitted through exposure to infected blood or body fluids, such as semen and vaginal fluids. HBV can cause acute or chronic liver disease, with chronic infection leading to liver cirrhosis, liver failure, and liver cancer. The virus can survive outside the body for up to seven days, making it highly infectious.

The HBV genome is approximately 3.2 kilobases in length and encodes for four overlapping open reading frames that produce seven viral proteins. The S protein is the surface antigen that mediates viral entry into host cells, and antibodies to this protein are used in diagnosing HBV infection. The core antigen (HBcAg) encapsidates the viral genome, and antibodies to this protein are used to diagnose acute infection. The virus also produces HBeAg, a soluble protein that is an indicator of active viral replication and is associated with an increased risk of liver disease progression.

Chronic HBV infection can be managed with antiviral therapy, such as nucleoside analogues, which suppress viral replication and reduce the risk of liver disease progression. A highly effective HBV vaccine is available and is recommended for all infants and individuals at high risk of infection.

Hepatitis C Virus (HCV):

Hepatitis C virus (HCV) is a single-stranded RNA virus that is transmitted through exposure to infected blood, typically through sharing of needles or injection drug use, blood transfusions (prior to 1992), or in rare cases, sexual contact. HCV is a leading cause of chronic liver disease worldwide and is a major public health concern.

The HCV genome is approximately 9.6 kilobases in length and encodes for a single polyprotein that is cleaved into structural and non-structural proteins. The viral envelope contains two major glycoproteins, E1 and E2, which mediate viral entry into host cells. HCV has a high degree of genetic diversity, with at least six distinct genotypes and multiple subtypes, which can affect disease progression and response to treatment.

Acute HCV infection is often asymptomatic, and up to 80% of individuals will develop chronic infection, which can lead to liver cirrhosis, liver failure, and liver cancer. Antiviral therapy with direct-acting antivirals (DAAs) can cure HCV infection in over 95% of cases, but access to treatment remains a major barrier, particularly in low- and middle-income countries.

In summary, HBV and HCV are both major causes of chronic liver disease and are transmitted through exposure to infected blood or body fluids. While a highly effective HBV vaccine is available, there is no vaccine for HCV, and access to antiviral therapy remains a major challenge for both viruses. Hence, they are considered one of the most deadliest viruses in the world.


Most deadliest viruses in the world pose a significant threat to global health and understanding their pathogenesis, transmission, and treatment is critical in mitigating their impact. As we have seen with viruses such as SARS-CoV-2, hepatitis B, and hepatitis C, these viruses can cause a range of acute and chronic illnesses, from respiratory disease to liver disease and cancer, leading to significant morbidity and mortality.

However, advances in scientific research, including the development of effective vaccines and antiviral therapies, have shown that it is possible to prevent and treat these infections. Additionally, public health measures such as widespread testing, contact tracing, and social distancing have proven effective in controlling the spread of viral infections.

It is essential that we continue to invest in research and public health initiatives to combat these viruses and prevent future pandemics. We must also remain vigilant and prepared for emerging viral threats by promoting global cooperation and collaboration among researchers, public health officials, and governments.

Ultimately, by increasing our knowledge and understanding of life-threatening viruses, we can better protect ourselves and our communities and work towards a healthier and safer world for all.

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