Saturday, February 18, 2017

The WAGD disease of the Day: Bill Gates is worried.

ll Gates hyperventillates and worries an epidemic might kill 30 million people. He cites Ebola as an example.

well, duh. Simple influenza kills half a million each year, (and the Spanish Flu in 1918 probably killed 30 million people),  but there are other ordinary germs that kill a lot of people but don't get a lot of publicity.

From Live Science: dangerous viruses that kill a lot of people include HIV, Rabies, Influenza, Dengue Fever, and Rotavirus (which causes diarrhea),

I would put Measles into that statistic, but thanks to vaccines, (and partly thanks to Bill Gate's money to fund the vaccine) the number of measles deaths has dropped 70+%, and now only killed 134 thousand people in 2015.

CDC has statistics on diseases prevented by vaccines, 1900 to 1990...

For example, in 1900, 21,064 smallpox cases were reported, and 894 patients died (1). In 1920, 469,924 measles cases were reported, and 7575 patients died; 147,991 diphtheria cases were reported, and 13,170 patients died. In 1922, 107,473 pertussis cases were reported, and 5099 patients died (2,3).

TABLE 2. Baseline 20th century annual morbidity and 1998 provisional morbidity from
nine diseases with vaccines recommended before 1990 for universal use in children
-- United States
                             Baseline 20th century     1998 Provisional       %
Disease                        annual morbidity           morbidity       Decrease
Smallpox                            48,164*                    0            100%
Diphtheria                         175,885+                    1            100%&
Pertussis                          147,271                6,279           95.7%
Tetanus                              1,314                  34             97.4%
Poliomyelitis (paralytic)           16,316                 0              100%
Measles                            503,282                89              100%&
Mumps                              152,209                606             99.6%
Rubella                             47,745               345             99.3%
 Congenital rubella                    823                 5             99.4%
Haemophilus                         20,000                54****         99.7%
 influenzae  type b

but of course the Hollywood anti vaxer type prefer fake news to actual numbers.

some of theses diseases I have seen, either in the US (I graduated before MMR vaccine existed) or overseas; others like diphtheria and small pox, our older collegues had seen them and told us stories. I remember one telling us that the Infectious disease hospital in our city had a bell, to alert doctors that a diphtheria patient had arrrived and needed an emergency tracheostomy to keep him from choking to death.

and not that about congenital rubella? worse than Zika...

Related item: A huge epidemic killed off most of native Mexicans years after the Spanish conquest. i.e. conquest was 1520, so the smallpox etc they brought would have killed then. But there was a larger epidemic of unknown cause from 1545 to 1550.

There are articles written about it's strange epidemiology, and some historians note that previous epidemics had occurred before the Spanish arrived.

The rise and fall of civilizations in the Americas occurred on and off in the 2000 years before Colombus arrived; how much of this was from climate change and how much from disease, or from both is unclear, since these things are related.

some demographic surveys suggest there were a lot of health problems and malnutrition in the area before the Spanish came. They also analyze the demographic collapse numbers that are published.

ah but did the Europeans bring the "pest" that essentially depopulated Mexico in the 1500's?

well, Archeology Magazine now says some scientists say the 1545 epidemic might have been a varient Salmonella, and yes probably came over from Europe.

The scientists sequenced bacterial DNA obtained from the teeth of 29 people who had been buried in southern Mexico, and compared the samples to a database of more than 2,700 modern bacterial genomes. The DNA recovered from several of the individuals matched that of Salmonella. Further testing suggests the strain is a rare one that today causes enteric fever and can be fatal without treatment. Evidence for the presence of the same strain of bacteria has been found in a woman who was buried in Trondheim, Norway, around the year A.D. 1200. The study suggests that the bacteria may have been carried by Spanish explorers to the New World. To read in-depth about the study of ancient DNA, go to “Worlds Within Us.”
Salmonella strains include dysentary (bloody diarrhea) but also typhoid fever; it is spread via water contaminated by feces, and direct contact.

there were several epidemics that caused the population collapse: NIH article here.  suspected rat bourne illnesses, e.g. Hanta virus etc.

like the recent hantavirus outbreak among the Navajo, drought and rodent infestation could have been behind  the 1545 and 1576 epidemics.

 In 1545 the epidemic affected the northern and central high valleys of Mexico and ended in Chiapas and Guatemala . In both the 1545 and 1576 epidemics, the infections were largely absent from the warm, low-lying coastal plains on the Gulf of Mexico and Pacific coasts . This geography of disease is not consistent with the introduction of an Old World virus to Mexico, which should have effected both coastal and highland populations.

but if it was due to salmonella (i.e. water borne or contact spread), drought could also explain this, especially if feces contaminated the water supply.

So the really really scary part of all of this is this chart:

Acuna-Soto R1, Stahle DW, Cleaveland MK, Therrell MD. - Emerging Infectious Diseases, April 2002; vol 8 (number 4), pages 360-2

on the other hand:
I'll repost the first  chart  that puts the population fluctuations into perspective. BP means before present:

 The graph shows the population of the Valley of Mexico expanding from fewer than 5,000 inhabitants 3,500 years ago to some 1-1.2 million in 1519. Three long cycles of growth stand out—3500-2100 BP, 1850-1250 BP, and 850-500 BP—, punctuated by two periods of decay—2100-1850 BP and 1250-850 BP. Region-wide decline is explained sometimes by exogenous factors—a cooling climate or severe seismic activity—and at others by endogenous developments or lack thereof, such as population pressure, economic decay, or political disintegration.
if this was indeed Salmonella, then one would have to figure out if the drought and water supply was to blame for it's spread... one of the articles discusses this.

I'll have to read up, but it does make one wonder if the next epidemic could be better stopped by clean water and isolation techniques than with fancy methods.

Indeed this  how Ebola (and SARS) was stopped: Isolating cases, and cleaning hands.

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