Diseases directly impact health and demographic indicators such as mortality rates, life expectancy, and sex and age distributions. The impact of diseases is a challenge to all sectors alike. Besides health issues, diseases also pose a development concern, affecting education and knowledge acquisition, income, social status, productivity and economic growth.
Let us look at some of the most deadly diseases that plagued mankind:
6. Smallpox (430 BC – 1979):
Smallpox, that also goes by the Latin names Variola or Variola vera, is one of the deadliest diseases in history to have ever plagued human life. During the 20th century, the disease claimed 300 to 500 million lives before it was eradicated as a result of worldwide vaccination campaign by WHO in 1980.
A contagious disease unique to humans, it was caused by either of the two virus variants: Variola major and Variola minor. Long-term side-effects were the distinctive skin scars while rare side effects were infertility in male survivors and blindness.
Smallpox killed around 60 million Europeans in the 18th century. Even five reigning European monarchs lost their lives to this disease. Up to 30% of those affected, including 80% of the children under 5 years of age, died from the disease while another one third turned blind. It is suspected that smallpox was responsible for killing majority of the native inhabitants of the Americas. It had also killed most of the Aztec army, the emperor, and one fourth of the overall population.
It is believed to be the only human communicable disease to have been completely eradicated.
5. Spanish Flu (1918 – 1919):
Spanish Flu is one of the deadliest flu pandemics in history. Having infected about one third of the world’s population at the end of World War I, the disease claimed 50 to 100 million lives in less than 2 years.
Believed to be caused by H1N1 influenza virus, this was a more severe version of the typical flu, with the usual symptoms of sore throat, headaches and fever. In many cases, the disease quickly progressed to a stage with extreme chills and fatigue, often accompanied by fluid in the lungs.
It came as a surprise for the Americans to realize that a quarter of their population, and a billion people worldwide had been infected with the deadly disease. More than half a million lost their lives in the U.S. alone.
Till date, there is no cure for the influenza virus.
4. Bubonic Plague (1340 – 1771):
Bubonic plague is another of the most deadly pandemics in history of human life. With a death count of 75 million people worldwide, this was the biggest reason for the Black Death. Since the invention of antibiotics, successful treatments are possible for this presently extremely rare but occasional disease.
Caused by the bacterium Yersinia pestis that is transmitted to humans through bites of flea that have fed on an infected rodent, this disease is marked by painful lymph node swellings (buboes) usually around base of the neck, in armpits and groin that oozed pus and bled. A high fever along with headaches, painful aching joints, nausea and vomiting, and a general feeling of malaise was characteristic of this disease. There was damage to the skin and underlying tissue before the victims’ skins were covered with dark blotches. Most victims succumbed within four to seven days after infection.
It began in South-western and Central Asia and spread to Europe by the late 1340s killing about one third of the population in medieval Europe and another 38,000 Londoners in the second wave.
With a mortality rate of thirty to seventy-five percent this plague had a drastic effect on Europe’s population, irrevocably changing Europe’s social structure.
3. Malaria (1600 – today):
Malaria, known to kill around 2 million people every year, is one of the most common infectious diseases and an enormous public-health problem. It causes at least one death in every 30 seconds approximately.
The disease is caused by a parasite from the genus Plasmodium and transmitted through the bite of an infected female Anopheles mosquito. The parasites multiply within red blood cells, causing light headedness, shortness of breath, tachycardia, fever, chills, nausea, flu-like illness, and in severe cases, coma and death. Young children and pregnant women are the most vulnerable to malaria.
The disease is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa. Most of the cases occur in rural areas where affordable health care is a distant possibility, and therefore the exact statistics of related fatalities remain unclear.
With no vaccine been developed so far, treatments are not always effective. It is feared that with the current upward rate of malaria cases, the death rate could double in another twenty years.
2. AIDS (1981 – today):
AIDS (Acquired Immunodeficiency Syndrome) has claimed the lives of more than 39 million people making it one of the most destructive epidemics recorded in history. Despite strenuous prevention strategies, the number of people infected with this remains high.
The systemic autoimmune disease caused by the human immunodeficiency virus (HIV) cannot be cured but new revolutions in medicines have dramatically brought down the death rate in the developed countries. Safe sex and the use of sterile needles remain the only HIV preventive measures.
The Sub-Saharan Africa remains the worst-affected with South & South East Asia second in line.
1. Cholera (1817 – today):
Cholera, one of the deadliest and most feared diseases of the century, kills more about 100,000 people every year. It is claimed to have hit in 8 pandemics, starting from 1817, with the last one from 1991 till present date. In the 19th century, it has become one of the first global diseases in a series of epidemics that has the highest mortality rate.
Being a bacterial disease that spreads through contaminated water, it can easily be treated by re-hydration, intravenous fluids and antibiotics only if attended to immediately. Prompt medical help is crucial because death from cholera can occur in a matter of hours.
It is thought to be virtually eliminated in the developed nations but is still relatively common in poor countries mostly due to unhygienic conditions.
Even with vaccines and modern medicines in place, report of 570 cases of cholera already in the last 3 weeks in Yemen gives us an idea of the possible threats of cholera. Despite all this, cholera isn’t even on the agenda of global health officials. The end to cholera’s long history is only possible when clean water becomes easily accessible for everyone.