Disease and the Settlement of the Americas

I ran across a report I had made to help the late Rick Holm, MD, with a presentation he was making – I don’t recall if he was president of South Dakota’s Medical Association at the time, or the specific group that made up his audience. As I looked at it, I realized that there was a lot of information in the answers to Rick’s questions.  When I wrote this, I was both teaching the class Indians of North America (senior level and graduate students) and South Dakota’s State Demographer – which probably explains enough.

The topic was the effects of disease on the Native American population following European contact and colonization. Another way to look at the topic is “why do we speak English instead of Swedish in North America? It may have been that the fighting abilities of the northeastern Indians and the Inuit were so discouraging to the Norse that European invasion was delayed by 500 years, but it may not.

The first question is why weren’t the Native Americans capable of resisting the post-Columbus European invasion?  It becomes more significant if we look at the failure of the Norse to successfully colonize North America – and I think we can make a pretty good argument that the old Swedes and Norwegians, traveling in open ships across northern waters, with stops in Iceland and Greenland, were pretty healthy people . . . and that their failure to make successful colonies (while the Spanish, French and English were so successful) was due to the fact that they did not introduce new diseases onto the North American continent.

The first major outbreak of an infectious disease recorded on the northeastern Atlantic coast was 1616-19. The Massachusetts and other Algonquin tribes in the area were reduced from an estimated thirty thousand to three hundred (Bray). When the Pilgrims landed a year later in 1620, there were few Indians left to greet them. Many observers believe this infectious disease was smallpox.  The Norse might have been just as aggressive as the later European settlers (but in my view) they lacked the advantage of contagious diseases.

The second question is why the diseases didn’t flow both ways – with North American diseases infecting and damaging Europe as severely as European diseases more than decimated the American population.

According to Jared Diamond – “The part of that question that’s easiest to answer concerns the reasons why Eurasia evolved the nastiest germs. It’s striking that Native Americans evolved no devastating epidemic diseases to give to Europeans, in return for the many devastating epidemic diseases that Indians received from the Old World. There are two straightforward reasons for this gross imbalance. First, most of our familiar epidemic diseases can sustain themselves only in large dense human populations concentrated into villages and cities, which arose much earlier in the Old World than in the New World. Second, recent studies of microbes, by molecular biologists, have shown that most human epidemic diseases evolved from similar epidemic diseases of the dense populations of Old World domestic animals with which we came into close contact. For example, measles and TB evolved from diseases of our cattle, influenza from a disease of pigs, and smallpox possibly from a disease of camels or rodents. The Americas had very few native domesticated animal species from which humans could acquire such diseases.”

Malaria and Yellow Fever came into the New World along with African slaves – the mosquitoes started spreading the diseases.

Question three — Measles seems to be a pretty mild disease to make a big difference.   Why is it on the list?

In Mann’s 1491, he describes the introduction of measles to the Yanomami Indians living near the Brazil-Venezuela border (missionaries in 1967).  James Neel and Napoleon Chagnon flew in with several thousand doses of vaccine, and tried to make an “epidemiological firebreak” by vaccinating ahead of the disease.  Despite the vaccine, the affected villages had a mean death rate of 8.8 percent.  The implication is that Indians were more vulnerable to European diseases than Europeans.  In 1824, King Kamehameha and Queen Kamamalu of Hawaii visited England, attended the theatre in the English King’s own box – Queen Kamamalu died of measles on July 8, Kamehameha on the 14th.  They were healthy young adults, in their mid-twenties, but their bodies couldn’t handle the relatively gentle European disease.

The age-adjusted mortality rates for the following causes were higher among American Indians than among all races in the US in 1983:

Tuberculosis–560% greater

Alcoholism–374% greater

Accidents–135% greater

Diabetes–107% greater

Homicide–91% greater

Pneumonia and influenza–39% greater

Question 4- How about bubonic plague – the Black Death – the European settlers must have brought it along?

Probably – but bubonic plague is present across the Western US, and probably has been for a long time.  The animal connection is there – it’s a disease found in wild rodents (ground squirrels) and passed from rodent to human by fleas.  Modern statistics show the Navajo as the people most likely to get the disease – but the demographic analysis shows that it is not a question of susceptibility to the disease – its that there are more Navajo where the disease is . . . Navajo cases are first, but Caucasians cases are in proportion their population.  Case fatality rates were actually a touch lower among the Navajo, but not significantly – and with the nation’s center for plague on the Navajo Reservation, this may be a situation where the local medical people are a little better at diagnosis.

It was a lot more serious in Europe because rats work harder at living close to people than prairie dogs and ground squirrels do.

Question 5 – How about flu?

TABLE 1. Comparison of the number and rate of deaths related to 2009 pandemic influenza A (H1N1) among American Indian/Alaska Natives (AI/ANs)* and persons in non-AI/AN populations, by age group — 12 states, April 15–November 13, 2009
Age group (yrs)Total deathsAI/AN deathsAll racial/ethnic populationsAI/ANNon-AI/AN populations§ Rate ratio AI/AN to non-AI/AN(95% CI)
≥658471. (2.3–10.8)
Total42642**1.0††3.7††0.9††4.0 (2.9–5.6)
* All AI/ANs were non-Hispanic. Per 100,000 population. § Includes 19 persons with unknown race/ethnicity. Confidence interval. ** Alabama (one death), Alaska (two), Arizona (16), Michigan (zero), New Mexico (eight), North Dakota (zero), Oklahoma (three), Oregon (one), South Dakota (four), Utah (two), Washington (four), and Wyoming (one). †† Age adjusted to the 2000 U.S. standard population.

Just in this last go-round, the H1N1 flu, mortality among American Indians and Alaska natives was four times higher than among the rest of our population (CDC, 12/11/09). The Spanish flu, back around 1918 – most of us know that researchers have recovered samples of that virus from bodies buried in permafrost in Alaska, where fatalities among Native populations reached 90 percent. On the other hand, some communities on South Dakota Reservations fared equally badly – and some of the reports from boarding schools on the Navajo Reservation showed the entire (white) teaching staff converted to nursing staff for schools and communities, moving when they heard of new outbreaks.

Question 6 – What does demography have to do with this?

The diseases that we recognize as particularly lethal to the American Indians – like smallpox, measles, tuberculosis, and influenza – tend to kill off a disproportionate part of the 15 to 45 population . . . the folks who take care of the young and the old. Basically it’s what demographers refer to as the dependency ratio. A culture that loses that 15 to 45 year-old group is going to lose more of the young and old too, as it loses the age group that provides most of the care. There was a second whammy, when the caretakers couldn’t help the most dependent through recovery.

Question 7 – what happened in the Dakotas?

If we look at the winter counts – records painted on leather – of our own Dakota, the Sioux, we see this:

            1780-1781       Smallpox

            1801-1802       Smallpox

            1810                Smallpox

            1813-1814       Whooping Cough

            1818-1819       Measles (“little smallpox winter”)

            1837                Smallpox

            1845-1846       “many sick winter”

            1849-1850       Cholera

            1850-1851       Smallpox

But compared to their neighbors the Sioux minimized the effects of these new diseases. With the tipi, they had the ability to move readily, and their social structure was based on the tiospaye – kind of a large family group – so it was natural for them to scatter across the country in relatively small, kind of isolated separate groups – the Sioux had a social structure that made a partial, seasonal quarantine a regular situation. On the other hand, the farming tribes, like the Mandan, had large permanent villages, permanent earth-walled buildings, and stayed in one place in a large group. After the smallpox epidemic of 1837, there were 125 or fewer Mandans left alive. Their population was estimated at 9,000 prior to white contact. And there are tribes that weren’t as successful in dealing with the diseases as the Mandan were.

Question 8: I’ve heard that smallpox was deliberately spread among the Indians by the army, by the government. What can you say about that?

It happened, but it wasn’t common. Historically, we know that during a parley at Fort Pitt on June 24, 1763, Captain Simeon Ecuyer gave representatives of the besieging Delawares two blankets and a handkerchief that had been exposed to smallpox, in hopes of spreading the disease to the Indians in order to end the siege. That’s the only documented case a military attempt at infection. It was enough to motivate Washington to vaccinate the entire Continental Army during the Revolution – apparently he figured that if the Brits would expose Native Americans, they’d also be willing to share with their white enemies. On the Plains, in the late 1830’s, Jim Bridger credited the Crow and Jim Beckwourth with sending smallpox exposed blankets to the Blackfeet in a case of opportunistic bio-warfare.

The interesting thing is that, in 1832, Congress had appropriated funds for the army to inoculate the Plains tribes against smallpox. It was only $1,200 dollars, and they expected Army doctors at forts so do the work . . . but it is a spot where history shows the US government trying to stop smallpox instead of trying to spread it.

I suspect that more items that had been exposed to smallpox went as trade items and loot than were intentionally used as bio-warfare agents. Even used blankets had value, and if you had already survived the disease, a village that had been annihilated or abandoned after smallpox would have been a cheap source of second-hand trade goods.

Question 9: What are the current health differences among American Indians?

            This is, in a way, the easiest question to answer – several of our counties have populations where American Indians make up well over 80 percent of the population, so we can readily get the data from state records. Diabetes comes to mind – raw numbers don’t show if the cause is genetic predisposition or diet – but it is definitely there. My guess is that both factors are at work – but there has been a tremendous change in the human diet over the past couple of centuries, and it’s even more extreme on our Reservations. Other health differences include more liver problems, higher infant

mortality rates, some higher cancer rates . . . but let’s stress that these aren’t the epidemics that occurred during white settlement. These chronic diseases aren’t the same as virgin field epidemics.

Question 10: Did the Native Americans have any nutrition-related health problems at the time of European contact?

At contact, North America had a lot of farming Indians. The main crops were corn, squash and beans, while animal protein came from hunting . . . where the farming was good, the archaeological record shows large towns . . . and the buried remains show that corn was the primary food. Among the Anasazi, we find teeth damaged by the small pieces of stone added in the grinding process, and a lot of bone loss along the jaws from abscesses. At Cahokia (down by St. Louis) the human remains suggest too much carbohydrates and too little protein.

On the other hand, a study by Franz Boas in 1890 showed that the average Plains Indian was taller than his or her White American peer at the time – but most of the folks in the study were raised in a buffalo hunting society. Whether in the New World or the Old World, farming provided a way for more people to make a living – but not a balanced diet.

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