As mankind and civilizations flourished, so did numerous infectious diseases. With increase in population, living in close proximity, poor sanitations, malnutrition, poverty have all been the reasons why humans have faced lots of challenges through all these several hundreds of years. Although past pandemics have wiped out parts of the population, medical and public health initiatives were able to halt the spread of other diseases. Have a look into 5 worst pandemics that world has faced.
The Black Death – Plague pandemics
Plague, has been documented in the pages of history as one of the worst pandemics disease around the world. Even India has faced Plague. It had several episodes at different places and time. Plague pandemics has been described to be the greatest challenges of olden times. The Black Death, which hit Europe had claimed nearly 200 million lives. Historians say that, Black Death was the time when ‘Quarantine’ was discovered.
Key facts on Plague:
- Plague is caused by the bacteria Yersinia pestis, a zoonotic bacteria usually found in small mammals and their fleas.
- Incubation period of one to seven days.
- There are two main clinical forms of plague infection: bubonic and pneumonic. Bubonic plague is the most common form and is characterized by painful swollen lymph nodes or ‘buboes’.
- Plague is transmitted between animals and humans by the bite of infected fleas, direct contact with infected tissues, and inhalation of infected respiratory droplets.
- Antibiotic treatment is effective against plague bacteria, so early diagnosis and early treatment can save lives.
Smallpox was one of the devastating pandemics. On average, 3 out of every 10 people who got it died. Those who survived were usually left with scars, which were sometimes severe. Origin of small pox remains unclear, however it has been documented since 4th century BC in the Egyptian empire. Due to the increased trade exchanges and invasions in various parts of the world, small pox was spread like wild fire.
Key Facts on Small Pox:
- Caused by the variola virus.
- Early symptoms include high fever and fatigue.
- Contagious and spreads through person-to- person contact and saliva droplets in an infected person’s breath.
- Incubation period of between 7 and 17 days.
- The virus then produces a characteristic rash, particularly on the face, arms and legs. The resulting spots become filled with clear fluid and later, pus, and then form a crust, which eventually dries up and falls off.
- There is no cure for smallpox, but vaccination can be used very effectively to prevent infection from developing if given during a period of up to four days after a person has been exposed to the virus.
- Recently, in July 2018, the FDA approved Tecovirimat (TPOXX) for treatment of smallpox.
- In laboratory tests, Cidofovir and Brincidofovir have been shown to be effective against the virus that causes smallpox.
The Spanish Flu pandemics
Three influenza pandemics occurred at intervals of several decades during the 20th century, the most severe of which was the so-called “Spanish Flu” (caused by an A(H1N1) virus), estimated to have caused 20–50 million deaths in 1918–1919.
Key facts on Spanish Flu:
- Caused by an H1N1 virus, with an avian (bird) origin; Attacks the respiratory system.
- The flu virus is highly contagious: When an infected person coughs, sneezes or talks, respiratory droplets are generated and transmitted into the air, and can then can be inhaled by anyone nearby.
- When the Spanish flu hit, doctors and scientists were not clear what caused it or how to treat it. Unlike today, there were no effective vaccines or antivirals, drugs that treat the flu.
- Quarantines were imposed; social gatherings like church, schools were shut. People were asked to stay indoors, use mask and regulations to ban spitting was imposed.
- After showing its disastrous phase, Spanish flu ended in 1919.
- In the later years H1N1 (Swine Flu) disease has reoccurred in several countries, however has not caused disastrous affects like the olden days.
HIV/ AIDS pandemic
Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) were first discovered in the early 1980s. HIV infection in India was first detected in 1986 among female sex workers in Chennai. With its prevalence across the world, HIV/ AIDS have been categorized under pandemics by WHO. However, with increasing access to effective HIV prevention, diagnosis, treatment and care, including for opportunistic infections, HIV infection has become a manageable chronic health condition. Medical advancements have enabled people living with HIV to lead long and healthy lives.
Key facts on HIV/ AIDS:
- HIV continues to be a major global public health issue, having claimed more than 32 million lives so far.
- The virus destroys and impairs the function of immune cells, infected individuals gradually become immunodeficient. Immune function is typically measured by CD4 cell count.
- The most advanced stage of HIV infection is acquired immunodeficiency syndrome (AIDS).
- HIV transmission is only possible if body fluids come in contact with a mucous membrane or damaged tissue or are directly injected into the bloodstream (from a needle or syringe). Mucous membranes are found inside the rectum, the vagina, the opening of the penis, and the mouth.
- HIV can be diagnosed through rapid diagnostic tests that can provide same-day results. This greatly facilitates diagnosis and linkage with treatment and care.
- There is no cure for HIV infection. However, effective antiretroviral drugs (ARVs) can control the virus and help prevent onward transmission to other people.
- Safer sexual practices, avoiding drug injections and abuse, Pre and post exposure prophylaxis are important for prevention of transmission of the disease.
The Coronavirus – COVID19 pandemic
The year 2020 was projected to be a year of great accomplishments in terms of development. However, the early months of 2020 has proved to be disappointing and disheartening due to the Coronavirus pandemic around the globe. Claiming several lives around the world, COVID19 has disrupted the life in several ways.
With the coronavirus pandemic, people all over the world have become more aware of the best practices during a pandemic, from careful hand-washing to social distancing. Countries across the world declared lockdown measures, closing schools, businesses, and public places. Several pharmaceutical companies and national health organisations like ICMR, CDC and many more independent researchers began working on tests, treatments, and vaccines.
With each pandemic, researchers, public health experts and international organizations have gained a better understanding of the complexity and dynamics of pandemics. With the improvement of surveillance and reporting systems, more data and characteristics of viruses can be documented than was possible a decade ago. Let us hope for brighter days and be prepared in much better ways to tackle any pandemic situations ahead.