human health and disease
Our 21st century world has many problems. Nonetheless it is much a safer world then the 19th century world of our ancestors, or even the 20th century world of our parents. We often forget that in the 19th century 4 out of every 10 infants born died before their 5th birthday, that many tens of millions have died of famine or from major pandemics since 1800.
Chronically Malnourished
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Yes even in 1960 some 1 billion people or about 33% of the world's population were chronically malnourished. Recent decades have seen a significant lowering in both numbers and percent of chronically malnourished, yet it is sobering some 800 million remain starving. Worse, the number of chronically malnourished has begun to creep upwards since 2016.
Please don't read too much into the % chart -- the decrease is largely from rapid increase in total population.
Summary: It appears that worldwide we have some 800 million people chronically malnourished. Why? Reportedly the primary reason is human conflicts (e.g. Yemen) , second is climate (e.g. drought in Ethiopia).
2019 Update: Slight increase again in 2018; chart extended forecast to 2200.
Oct 2020 Update: We continue to run some 800 million people chronically malnourished. Since forecast shows roughly flat number malnourished whie the total world population is forecast to increase, the % Malnourished chart misleadingly shows an improving %.
Please don't read too much into the % chart -- the decrease is largely from rapid increase in total population.
Summary: It appears that worldwide we have some 800 million people chronically malnourished. Why? Reportedly the primary reason is human conflicts (e.g. Yemen) , second is climate (e.g. drought in Ethiopia).
2019 Update: Slight increase again in 2018; chart extended forecast to 2200.
Oct 2020 Update: We continue to run some 800 million people chronically malnourished. Since forecast shows roughly flat number malnourished whie the total world population is forecast to increase, the % Malnourished chart misleadingly shows an improving %.
World Infant Mortlity
Our 21st century world has many problems. Nonetheless it is much a safer world then the 19th century world of our ancestors, or even the 20th century world of our parents. We often forget that in the 19th century 4 out of every 10 infants born died before their 5th birthday. It is sobering to realize that our present mproved world still has many thousand of children die die every single day!
May 2018: Preliminary 2017 data right on forecast.
May 2018: Preliminary 2017 data right on forecast.
Deaths from Major famines
Deaths due to famine has been all too common through history. Causes range from droughts, locusts infestations, war, politics, and just generally too many people for agricultural capacity of an area to feed, often a combination of these causes. Wikipedia includes a detailed list of famine events since 441 BC.
My chart shows estimates for the major famines that have occurred since 1800, where I defined major as likely to have exceeded a minimum of 1 million deaths. I was shocked to learn the largest famine mortality since 1800 was mid-20th century. My forecast suggests major famines remain possible. Mind you sub-1 million death famines certainly do continue -- every year!
May2018 Update: Oops -- contrary to my previous report there have been 21st century mega-famines.
My chart shows estimates for the major famines that have occurred since 1800, where I defined major as likely to have exceeded a minimum of 1 million deaths. I was shocked to learn the largest famine mortality since 1800 was mid-20th century. My forecast suggests major famines remain possible. Mind you sub-1 million death famines certainly do continue -- every year!
May2018 Update: Oops -- contrary to my previous report there have been 21st century mega-famines.
deaths from mega-Pandemics
Even eliminating all pre-1800 pandemics, there is an over-whelming amount of information regarding disease pandemics. So devastating as pandemics that killed thousands, tens of thousands or hundreds of thousands of people, nonetheless, I have charted just the mega-pandemics that killed millions of people to obtain a simplified initial survey. Reviewing material towards preparing these charts has been very eye-opening!
Bubonic Plague PANDEMICS
The bubonic plaque is an infectious caused by the bacterium Yersinia pestis, thought usually to infect people via fleas from rats. When the infection primarily occurs in the lymph nodes this is is referred to as bubonic plaque, when it primarily occurs in lungs it is referred to as pneumonic plague, and when it primarily occurs in the blood it is refereed to as septicemic plague.. When unclear which, then often people refer just to bubonic plaque. The most notorious of these plagues must be the Black Death that killed an estimated 50 million or more people in the 14th century. Frankly I have yet to see a convincing argument why the Black Death came to and end. Was it just strict quarantines and improved hygiene?
My chart only covers the period post 1800. There has just been one major pandemic due to bubonic plague post 1800. As indicated, this flared up mid-nineteenth century. However I should emphasize that some literature suggests this pandemic sort of trailed off, continuing to about 1950.
My chart only covers the period post 1800. There has just been one major pandemic due to bubonic plague post 1800. As indicated, this flared up mid-nineteenth century. However I should emphasize that some literature suggests this pandemic sort of trailed off, continuing to about 1950.
Cholera Pandemics
Cholera is an acute diarrhoeal disease due to poor sanitation and infection by the bacteria Vibrio cholerae. Cholera usually has sudden onset and can be rapidly fatal without treatment. Fortunately cholera is preventable by good sanitation, and is treatable with re-hydration and antibiotics. It remains a serious threat in third world countries but not in developed countries.
There have been 8 major cholera pandemics since 1800, including 1 mid-20th century with deaths to many 100 thousands. Modern sanitation and medicine have greatly reduced cases and mortality, but we still are dealing with 100 thousands of cases per year.
My chart just shows just 4 modern mega pandemics. This arbitrary cutoff at i million hides from sight numerous cholera pandemics of tens and hundreds of thousand deaths.
There have been 8 major cholera pandemics since 1800, including 1 mid-20th century with deaths to many 100 thousands. Modern sanitation and medicine have greatly reduced cases and mortality, but we still are dealing with 100 thousands of cases per year.
My chart just shows just 4 modern mega pandemics. This arbitrary cutoff at i million hides from sight numerous cholera pandemics of tens and hundreds of thousand deaths.
HIV/AIDS PANDEMIC
HIV/AIDS is thought to have originated in Africa late 19th or early 20th century. It is a viral infection usually transmitted via unprotected sex, and by transfer of blood (etc.) such as by blood transfusions and reuse of injection needles. The disease was not characterized until 1980s. By then the mortality rate was sky-rocketing -- just look at the rising leg in my chart. Finally medical science was better able to control if not cure this disease -- see falling leg on chart. The forecast is for continuing slow decline in mortalities.
May2018 Update: on forecast.
May2018 Update: on forecast.
influenza PANDEMICS
Influenza is a readily spreadable viral infection. It is a serious health problem in that it can cause death in high risk populations. Fortunately, vaccination and antiviral drugs can lessen impacts. The influenza virus is worldwide. There are 3 types (A, B & C) and numerous sub-types. Since 1800 there have been 4 major influenza pandemics, the most serious by far being the 1918 so called Spanish flu, which pre-dated modern treatments.
As indicated to the right of the chart, future influenza lethal pandemics likely might occur in future decades, but likely modern treatments will reduce death rate, touch wood.
As indicated to the right of the chart, future influenza lethal pandemics likely might occur in future decades, but likely modern treatments will reduce death rate, touch wood.
Malaria Pandemic - Model
Malaria is an infectious disease caused by several species of single-celled parasitic protozoans and spread by certain species of mosquitos. This disease is widespread in tropical and subtropical areas. Risk of disease can be reduced by use mosquito netting, insect repellents, spraying of insecticides and draining of standing water. A number of anti-malaria medications have been developed though there is reported evidence of growing resistance. As far as I'm aware, there is not yet an effective vaccine. Much of the effort to control this disease necessarily is focused on controlling the mosquito population. However many third world countries find it difficult to cope with the necessary costs and effort. All the more so with negative pressure on DDT plus reported growing resistance to chloroquine.
I should emphasize that my chart just shows my model of malaria deaths. My chart shows 3 important points, all which are true I believe: malaria is an ongoing pandemic killing many hundred thousands of people per year, there was an unfortunate surge in mortality in the late 20th & early 21st century, and recent remedial measures are having a significant impact towards lessening malaria deaths.
May 2018 Update: Forecast significantly lowered since previous forecast twice stats published by WHO.
I should emphasize that my chart just shows my model of malaria deaths. My chart shows 3 important points, all which are true I believe: malaria is an ongoing pandemic killing many hundred thousands of people per year, there was an unfortunate surge in mortality in the late 20th & early 21st century, and recent remedial measures are having a significant impact towards lessening malaria deaths.
May 2018 Update: Forecast significantly lowered since previous forecast twice stats published by WHO.
smallpox Pandemic - Model
Smallpox is a deadly highly contagious viral infection that has killed many hundreds of millions of people throughout history. WHO reported some 200-500 million people died from smallpox in the 20th century, and that some 2 million people died from smallpox as recently as 1967. Successful vaccination programs have now eradicated smallpox worldwide as 1979.
My reading suggests high levels of deaths from smallpox somewhere most years since 1800, though of course some years much worse than other years. Best I could come up with was a simple model. The success of vaccination programs through 19th and 20th centuries is clearly visible.
My reading suggests high levels of deaths from smallpox somewhere most years since 1800, though of course some years much worse than other years. Best I could come up with was a simple model. The success of vaccination programs through 19th and 20th centuries is clearly visible.
typhus PANDEMICS
Typhus refers to epidemic typhus caused by a bacteria spread by body lice, but sometimes this term is used to refer to a group of similar diseases caused different insects and bacteria. I use the former definition. Typhus generally occurs where large numbers of people are grouped together under stressful conditions, especially during war conditions. Since 1800 there have been numerous reports of epidemic typhus but usually deaths number in thousands, tens of thousands or hundreds of thousands. Typhus killed many of Napoleon’s troops during his retreat from Moscow, killed many Irish during the Potato Famine including many Irish emigrants, and killed numerous people at Nazi concentration camps. As far as I can see it took the terrible conditions of World War 1 and the following war between White & Red Russian armies to push the typhus death rate into the multi-millions. While modern treatment practices have greatly reduced the rate of death, the best preventive measure has been modern insecticides.
As indicated to the right of the chart, future major lethal epidemic typhus pandemics might occur in future decades, but likely modern treatments will reduce death rate, touch wood.
As indicated to the right of the chart, future major lethal epidemic typhus pandemics might occur in future decades, but likely modern treatments will reduce death rate, touch wood.
Mega Episodic Pandemics
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Human folk have suffered many thousands of epidemics or pandemics. To cope with this huge topic I decided only to chart those pandemics that are estimated to have killed over 1 million people per pandemic episode. As usual my charts go from 1800 to present, and also include some future forecast. Each episode lasted years to decades.
Looking at this chart, the avian influenza (or Spanish flu) pandemic of 1919 stands out as by far the most devastating killer. And all 3 most recent mega episodic pandemics were influenza. But who would have thought the second worst killer since 1800 was bubonic plague -- I initially had thought that was from medieval times. The other mega episodic pandemics were cholera and typhus. And good news -- no mega episodic pandemic in past 50 years.
Looking at the forecasts influenza seems most likely disease to cause a future mega episodic pandemic.
Looking at this chart, the avian influenza (or Spanish flu) pandemic of 1919 stands out as by far the most devastating killer. And all 3 most recent mega episodic pandemics were influenza. But who would have thought the second worst killer since 1800 was bubonic plague -- I initially had thought that was from medieval times. The other mega episodic pandemics were cholera and typhus. And good news -- no mega episodic pandemic in past 50 years.
Looking at the forecasts influenza seems most likely disease to cause a future mega episodic pandemic.
MEGA Non-EPISODIC PANDEMICS
Some pandemics essentially are continuously ongoing year to year, i.e. are not episodic. Since 1800 thee have been three mega non-episodic pandemics that killed over 1 million people per year. Historically the big killer was smallpox, which medical science has now eliminated. The second mega non-episodic pandemic is malaria and the third HIV/AIDS. It appears medical science is bringing both malaria and HIV/AIDS under sufficient control that they will fall below the million deaths per year, but nonetheless both seem likely to continue to kill hundred thousands of people per year in future decades.
Note my charts are just model estimates not real data.
Note my charts are just model estimates not real data.
MEGA Episodic and NON-EPISODIC PANDEMICS
This chart shows both episodic pandemics (symbols) and non-episodic pandemics (lines to right). As usual forecasts are to left. Note that number if deaths are per episode for episodic pandemics and this might stretch over years or decades for each event. For non-episodic pandemics the lines indicate my models of annual deaths. For both episodic and non-episodic pandemics, results below 1 million are not charted.
The avian flu of 1919 remains as the most devastating by far of the modern episodic pandemics. The forecast suggests a future mega pandemic most likely would be influenza. Nonetheless it is important to realize non-episodic pandemics show deaths per year so must be multiplied by years of occurrence -- thus smallpox was the most deadly mega pandemic since 1800, followed by malaria. Thus malaria and HIV/AIDS must be watched carefully that we not lose control.
The avian flu of 1919 remains as the most devastating by far of the modern episodic pandemics. The forecast suggests a future mega pandemic most likely would be influenza. Nonetheless it is important to realize non-episodic pandemics show deaths per year so must be multiplied by years of occurrence -- thus smallpox was the most deadly mega pandemic since 1800, followed by malaria. Thus malaria and HIV/AIDS must be watched carefully that we not lose control.
MEGA PANDEMICS & mega Famines
I found it educational to chart mega famines alongside mega pandemics. It was an awfully scary world our ancestors survived. Both disease and famine have been greatly reduced by modern science, but both remain lurking in our future.