The world has witnessed the emergence of numerous deadly diseases that transcend borders, impacting lives and shaping the landscape of public health. Over the years, many dangerous diseases have been discovered, and they have wreaked havoc in different parts of the world. From smallpox to Ebola, diseases have caused significant suffering and loss of lives.
In this article, we will discuss the deadliest diseases in the world, their impact, causes, and symptoms. Also, know the significance of a health insurance policy and the financial support they provide for quality treatment of these diseases.
World's deadliest diseases that impacted human history
Throughout history, several deadly diseases have left an indelible mark on humanity, shaping populations and societies. The bubonic plague, known as the Black Death, decimated Europe in the 14th century, killing an estimated one-third of the population. Smallpox, a relentless killer, wiped out millions before being eradicated in the late 20th century. Influenza pandemics, particularly the 1918 Spanish flu, claimed millions of lives globally. Each of these diseases not only caused immense suffering but also spurred advancements in medicine and public health practices.
Here is the list of the most deadliest and dangerous diseases in the world
Ebola virus
Ebola virus disease is caused by viruses belonging to the Filoviridae family. There are five distinct species of the Ebola virus, each named after the region where it was initially discovered. Among them, Zaire ebolavirus is considered the most lethal, with a mortality rate reaching up to 90%.
Causes
The Ebola virus is transmitted to humans from wild animals and spreads through human-to-human transmission via direct contact with the blood, secretions, organs, or other bodily fluids of infected people. The virus has a high fatality rate and can lead to severe internal bleeding.
Symptoms
Early symptoms include fever, fatigue, muscle pain, and headache, progressing to vomiting, diarrhoea, impaired kidney and liver function, and, in some cases, internal and external bleeding.
Risk factors
Close contact with infected animals or individuals, inadequate healthcare infrastructure, and cultural practices such as burial ceremonies involving direct contact with the deceased contribute to the risk of Ebola transmission.
Bubonic plague
The Bubonic Plague, known as the "Black Death," is a highly infectious disease that swept through Europe and Asia in the 14th century, causing millions of deaths. It's caused by the bacterium Yersinia pestis, which lives in rodents and is spread by fleas.
Causes
The primary cause is Yersinia pestis, transmitted to humans via flea bites from infected rodents, especially rats. Direct contact with infected tissues or inhaling respiratory droplets can also spread the bacteria.
Symptoms
Common symptoms include fever, chills, headache, and swollen, tender lymph nodes (called buboes), typically near the bite site. Other signs may include fatigue and muscle pain, worsening quickly if untreated.
Risk factors
People living in unsanitary conditions, in close contact with rodents, or working in environments with wild animals are at greater risk. Poor hygiene, overcrowding, and lack of medical care increase susceptibility.
Smallpox
Smallpox, historically known as the "Speckled Monster," was a highly contagious and deadly disease that affected people worldwide for centuries. Caused by the Variola virus, it primarily spread through direct contact with infected individuals or contaminated objects. The disease was marked by a high mortality rate before its eradication in 1980, following a successful global vaccination campaign.
Causes
Smallpox is caused by the Variola virus, which spreads via respiratory droplets, direct contact with an infected person, or contaminated materials like bedding or clothing.
Symptoms
Symptoms start with high fever, fatigue, and severe headache, followed by a rash that develops into fluid-filled sores. These sores spread across the body and leave scars after healing.
Risk factors
Close contact with infected individuals, crowded living conditions, and lack of vaccination were major risk factors. Smallpox was especially dangerous for infants, pregnant women, and those with compromised immune systems.
Cholera
Cholera is a severe diarrheal illness caused by the bacterium Vibrio cholerae. It is commonly contracted by consuming contaminated water or food and can lead to rapid dehydration and death if untreated. Cholera outbreaks are frequent in regions with limited access to clean water and sanitation facilities. Timely rehydration and antibiotics are critical for recovery, and preventive measures include improving water quality and sanitation.
Causes
Cholera is caused by ingesting Vibrio cholerae-contaminated water or food. Poor sanitation, inadequate sewage systems, and lack of clean drinking water increase the likelihood of contamination.
Symptoms
Symptoms include severe, watery diarrhea, vomiting, and leg cramps, leading to rapid fluid loss. This can result in dehydration, shock, and, if untreated, death within hours.
Risk factors
People in areas with poor sanitation, limited access to clean water, and crowded conditions are at higher risk. Cholera outbreaks often occur during natural disasters or in refugee camps where infrastructure is compromised.
Ischemic Heart Disease (Coronary Artery Disease)
Ischemic Heart Disease (Coronary Artery Disease) is a condition where the coronary arteries narrow, reducing blood flow to the heart muscle. This can lead to chest pain, heart attacks, and other cardiovascular complications.
Causes
Ischemic Heart Disease is primarily caused by the buildup of plaque in the coronary arteries, leading to reduced blood flow to the heart muscle. This can result from high cholesterol, hypertension, and smoking.
Symptoms
Common symptoms include chest pain (angina), shortness of breath, and fatigue. Severe cases may lead to heart attacks, presenting with intense chest pain, nausea, and sweating.
Risk factors
Risk factors include high blood pressure, high cholesterol levels, smoking, diabetes, and a sedentary lifestyle. Family history and obesity also increase the likelihood of developing the condition.
Stroke
A stroke is a medical emergency where blood flow to the brain is disrupted, either by a blockage or bleeding. This interruption can cause brain cell damage, leading to sudden symptoms like weakness, confusion, and difficulty speaking or understanding.
Causes
Strokes occur when blood flow to a part of the brain is interrupted, either due to a blockage (ischemic stroke) or bleeding (hemorrhagic stroke). Risk factors include high blood pressure and atherosclerosis.
Symptoms
Symptoms of a stroke include sudden numbness or weakness on one side of the body, difficulty speaking, confusion, and severe headache. Immediate medical attention is crucial to minimize damage.
Risk factors
Risk factors include high blood pressure, smoking, diabetes, high cholesterol, and a history of heart disease. Age, gender, and genetics also play a role in stroke risk.
Chronic Obstructive Pulmonary Disease (COPD)
Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung condition caused by long-term exposure to irritants like cigarette smoke. Symptoms include chronic cough, shortness of breath, and wheezing. Major risk factors are smoking, air pollution, and genetic predispositions.
Causes
COPD is mainly caused by long-term exposure to irritants that damage the lungs, such as cigarette smoke and pollutants. Chronic bronchitis and emphysema are common forms of COPD.
Symptoms
Symptoms include persistent cough, shortness of breath, wheezing, and increased mucus production. These symptoms gradually worsen over time, affecting daily activities and quality of life.
Risk factors
Key risk factors include smoking, exposure to air pollutants, and a history of respiratory infections. Genetic factors and occupational exposures also contribute to the development of COPD.
Avian Influenza
Avian influenza, or "bird flu," is an infectious disease caused by influenza A viruses that typically affect birds but can sometimes spread to humans. Human infection often occurs through direct or indirect contact with infected birds or contaminated environments. Certain strains, like H5N1 and H7N9, have been known to cause severe respiratory illness in people, raising concerns about potential outbreaks and pandemics.
Causes
Avian influenza is caused by influenza A viruses found primarily in birds. Humans can contract the virus through contact with infected birds, contaminated surfaces, or inhaling droplets in infected areas.
Symptoms
Symptoms in humans can range from mild respiratory issues like cough and fever to severe pneumonia, muscle pain, and even multi-organ failure. In some cases, the disease can be fatal if not treated promptly.
Risk factors
People working with poultry, those in close proximity to infected birds, and those traveling to areas with outbreaks are at higher risk. Weak immune systems and lack of preventive measures can increase susceptibility to severe infection.
HIV/AIDS
HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, weakening the body's defences. If untreated, it can progress to AIDS (Acquired Immunodeficiency Syndrome). AIDS is the final stage of HIV infection, characterised by severe immune system damage and increased susceptibility to opportunistic infections and certain cancers.
Causes:
HIV is primarily transmitted through unprotected sexual intercourse, sharing of contaminated needles, and mother-to-child transmission during childbirth or breastfeeding. Blood transfusions with infected blood and organ transplants can also transmit the virus.
Symptoms:
Early stages may present with flu-like symptoms, while advanced stages can lead to opportunistic infections, cancers, and a compromised immune system.
Risk factors:
High-risk factors for HIV/AIDS include unprotected sexual intercourse, sharing needles or syringes, having multiple sexual partners, lack of male circumcision, and receiving contaminated blood or organ transplants.
Tuberculosis (TB)
Tuberculosis (TB) is a bacterial infection. It primarily affects the lungs but can affect other organs. TB spreads through airborne droplets and is a major global health concern, but it is treatable with antibiotics.
Causes:
Mycobacterium tuberculosis bacteria primarily cause TB, usually affecting the lungs but can also target other parts of the body.
Symptoms:
Persistent cough, weight loss, night sweats, and fatigue are common TB symptoms.
Risk factors:
Close contact with an infected person, weakened immune system, malnutrition, and conditions like diabetes increase the risk of contracting TB.
Leprosy
Leprosy, also known as Hansen’s disease, is a chronic infectious disease caused by the bacterium Mycobacterium leprae. Mentioned in historical texts, including the Old Testament, leprosy has long been feared for its disfiguring symptoms. However, modern medicine has made it curable through antibiotics, and early treatment can prevent disability and further spread.
Causes
Leprosy is caused by Mycobacterium leprae, which spreads through prolonged, close contact with an untreated infected person. It primarily affects the skin, nerves, and upper respiratory tract.
Symptoms
Symptoms include skin lesions, numbness in affected areas, and muscle weakness. In advanced stages, it can cause deformities and disabilities if left untreated.
Risk factors
People in areas with endemic leprosy, close contact with untreated individuals, and those with weak immune systems face higher risk. Living in crowded or unsanitary conditions also increases susceptibility.
Malaria
Malaria is a life-threatening mosquito-borne disease. It is a major global health concern, particularly in tropical regions.
Causes:
Malaria is caused by Plasmodium parasites transmitted through the bites of infected mosquitoes. Plasmodium falciparum is the deadliest species, causing the most severe form of the disease.
Symptoms:
Fever, chills, and flu-like symptoms are common, progressing to severe complications such as organ failure in some cases.
Risk factors:
Mosquito-infested areas, lack of proper preventive measures, and weak healthcare systems contribute to the spread of malaria.
Also, read: Health insurance plans for vector-borne diseases
Influenza
Influenza, commonly known as the flu, is a contagious respiratory illness. It can lead to severe complications, and annual vaccination is recommended for prevention.
Causes:
Influenza viruses, specifically influenza A and B, are responsible for seasonal flu outbreaks. These viruses can mutate, leading to new strains that may cause pandemics.
Symptoms:
Fever, cough, sore throat, muscle aches, and fatigue are typical symptoms. In severe cases, pneumonia and respiratory failure can occur.
Risk factors:
Crowded living conditions, lack of vaccination, and close contact with infected individuals increase the risk of influenza.
Coronavirus
Coronavirus refers to a family of viruses that can cause respiratory illnesses in humans. The novel coronavirus, SARS-CoV-2, led to the COVID-19 pandemic.
Causes:
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is responsible for COVID-19. The virus primarily spreads through respiratory droplets.
Symptoms:
Common symptoms include fever, cough, and difficulty breathing. In severe cases, COVID-19 can lead to pneumonia and acute respiratory distress syndrome (ARDS).
Risk factors:
Close contact with infected individuals, crowded settings, and certain underlying health conditions increase the risk of severe illness.
Read more: CoWIN Vaccine Certificate
Cancer
Cancer is a group of diseases characterised by the uncontrolled growth and spread of abnormal cells. It can occur in any tissue or organ and may form tumours.
Causes:
Various factors, including genetic mutations, environmental exposures, and lifestyle choices, contribute to the development of cancer.
Symptoms:
Symptoms vary depending on the type and stage of cancer but may include unexplained weight loss, persistent pain, changes in bowel or bladder habits, and unusual lumps.
Check out: Chemotherapy cost in India
Risk factors:
Tobacco use, exposure to carcinogens, genetic predisposition, and unhealthy lifestyle choices such as poor diet and lack of physical activity increase the risk of cancer.
Also, read: Health insurance for breast cancer
