“Revisioning smallpox in Mexico City-Tenochtitlán, 1520-1950:
What difference did charity, quarantine, inoculation and vaccination make?”
Robert McCaa, University of Minnesota
Large bumps spread on people, some were entirely covered.
They spread everywhere, on the face, the head, the chest, etc.
[The disease] brought great desolation; a great many died of it.1
1.1. Smallpox first erupted in Mexico Tenochtitlán, the ancient capital of the Mexica, in 1520. While the siege and conquest of the City by Hernán Cortés’s army and his native allies took less than four months (April 28-August 13, 1521), conquering smallpox took more than four centuries. In 1950, the City’s last smallpox deaths were recorded, four years before the virus was permanently eradicated from the Republic of Mexico, and almost three decades prior to its extinction from the planet. If mortality from any single smallpox epidemic in the City was never as great as Cortés’s murderous siege of 1521, over the centuries periodic eruptions of the disease killed thousands, even tens of thousands, often in a matter of weeks. Total smallpox deaths over the intervening 430 years probably exceeded those caused by the many invasions, wars, rebellions, and revolutions which afflicted the City.
1.2. Almost every Mexican school child can recite the dates of the nation’s major wars, but the chronology of smallpox in the City is not well known, even by historians. Likewise much of the history of the numerous, heroic efforts by City authorities to contain, prevent, and, finally, eradicate the disease remains to be written. The story of the virus in the City reveals much about the evolution of notions of charity, the nature of charitable initiatives, the class and character of the beneficiaries, and ideologies concerning public health.
2.1. Chronology. The first smallpox epidemic to strike the City is precisely known because in ancient times the disease was completely alien to the Americas, until introduced, inadvertently by Christians or their vassals, to the Caribbean in 1518. Almost two years passed before the disease spread to the Aztec capital, Tenochtitlan. Indian auxiliaries from Cuba accompanying an expedition to capture the rebellious Cortes provided the reservoir. Spanish chroniclers, aware of the foreboding omen for the native populations of the appearance of the pestilence on tierra firme, precisely identify the disease’s leap ashore in May 1520. The agent of transmission was one Francisco Eguia, a Black slave.2 The desultory spread of this virgin soil epidemic from the coast to the Mexica capital is surprising. Some four months were required to traverse a distance of 400 kilometers—over what must have been frequently traveled routes. Finally in late September or early October 1520, the smallpox plague erupted in Tenochtitlan. Transmission of the virus was, once again, by natives because the outbreak began at least two, but more likely three, months after the deadly flight of the Spanish invaders from the City on “noche triste,” June 30, 1520. In that battle, all captured Christians were sacrificed without delay. Therefore, months later when the epidemic erupted in the City itself, none were still alive to aid in containing the disease or caring for its victims, should any have been inclined to do so.3
2.2. A native chronicle written in Nahuatl provides the best description of this first smallpox outbreak in the City:
It began in Tepeilhuitl [at the end of September according to the contemporary Spanish gloss]. Large bumps spread on people, some were entirely covered. They spread everywhere, on the face, the head, the chest, etc. [The disease] brought great desolation; a great many died of it. ...
The disease of the pustules lasted a full sixty days; after sixty days it abated and ended. ...
It broke out in Teotl eco, and it abated in Panquetzaliztli. The Mexica warriors were greatly weakened by it.4
2.3. For most historians, a crude Darwinism explains the greater devastation of native peoples attacked by virgin soil epidemics, such as that of 1520.5 The conventional argument made by many historians of the early Americas is that natives lacked genetic immunity against the disease. Yet among geneticists and immunologists the notion that Europeans enjoyed genetic immunity against the smallpox virus remains an unproven, even unproveable, hypothesis.6
2.4. Was the greater destruction a matter of genes or care? Epidemiology may offer a means of resolving this conundrum. Since dehydration often leads to death in poorly-treated fever-causing viral infections such as smallpox, virgin soil mortality is heightened by the fact that adults, who might provide fluids, care and comfort for what is normally a childhood affliction, are themselves often deathly ill. Upon first exposure to smallpox, all adults—including Mexica warriors, according to the Nahuatl texts—as well as children succumbed to the disease. Mortality was unusually high due to a lack of healthy adult caregivers to provide water, food, or even a comforting word.
2.5. Chroniclers, native and Spanish alike, lament that the first epidemic was so great that there was no one to provide care, or even prepare tortillas, the staple of every Mexica meal. Unfortunately tortillas must be prepared fresh, otherwise they toughen and sour quickly if not consumed soon after preparation. Europeans enjoyed advantages, indeed, but they were above all epidemiological, rather than genetic. In Europe, the disease occurred with sufficient regularity so that most were afflicted in childhood. The immune systems of the overwhelming majority of survivors were tuned to successfully repel further infection from the virus. If genetic adaptation occurred, it was more likely in the DNA of the extremely short-lived, although highly stable, orthopox-virus than in much longer-lived humans.7
2.6. In 1538, a second smallpox outbreak occurred in Mexico Tenochtitlán. The authoritative pictorial year signs for the City, the Codex “Telleriano-Remensis,” depicts a male and female adult pair with “spotted bodies”, their “closed eyes” signifying death. The accompanying Spanish gloss explains that in that year “many people” died of smallpox,8 as opposed to “a great many” in the epidemic of 1520. That many adults were also victims of the outbreak of 1538 suggests that the virgin soil epidemic of 1520 was not universal, even in densely settled Tenochtitlán.
2.7. Curiously, for the entire sixteenth century, there is only one additional reference to the disease in or near the City and that for an earlier episode in 1531/32. The native chronicler Chimalpahin, writing in Nahuatl almost a century after the fact, stated: “Also in this year the epidemic of smallpox [çahuatl] proliferated and they were small pustules from which died [many] children.” For 1532, he continues, “In this year there was a great die-off in Chalco because of the smallpox; many elderly died in Tlalmanalco and in all of Mexico.” Other contemporary sources, texts and native pictographs attribute the cause of this second, less devastating, pestilence introduced by the Christians to measles.9
2.8. Throughout the sixteenth century great epidemics abound in the former Aztec capital, now renamed Mexico City, reconstructed, and increasingly Hispanized. Attributed variously to measles (zahuatl tepiton), mumps, cocoliztli (great pestilence), typhus (matlazahuatl), or multiple symptoms, which cannot be identified as specific diseases, smallpox is wholly absent from the list.10 Spaniards knew the smallpox scourge first-hand, from centuries of experience with epidemic outbreaks. Natives rapidly became familiar with the disease, coining, at first contact, the words “totomonalliztli” (pustules) and “huey zahuatl” (the great spots or leprosy) to identify it. Thus, there was little confusion among Spaniards or natives in recognizing an outbreak of smallpox. Then too, had there been further deadly eruptions of the disease it is unlikely that both chroniclers and authorities would have failed to seize the opportunity to attribute another massive die-off to the hand of god, rather than the hand of man.
3.1. Epidemic smallpox. Historians of smallpox in Mexico see the disease recurring with great regularity, endorsing the interpretation of the distinguished eighteenth century German scientist baron Alexander von Humboldt. Humboldt wrote that after 1520 smallpox seemed to strike the capital every seventeen or eighteen years.11 In fact, after 1538, a prolonged respite of almost eight decades ensued, with the next great smallpox epidemic striking the City in 1615. The succeeding bout erupted in 1653, a lapse of almost four decades. Then, the baron’s rule seems to have taken hold. Over the next century and a half smallpox culled 5-10% of the City’s population every decade or two. Significant epidemics are recorded for 1663, 1673, and 1696, totaling five for the seventeenth century. Six outbreaks occurred in the eighteenth: 1711, 1733/34, 1748, 1761/62, 1779/80 and 1797/98.12
3.2. Then, in 1804, Jenner’s vaccine became available in Mexico, thanks to a worldwide philanthropic expedition sponsored by the Spanish king Charles IV and led by a Spanish naval officer, Dr. Francisco Javier de Balmis.13 Popular acceptance of the new procedure was widespread, yet, after the first campaigns, vaccination was practiced intermittently, until a new epidemic threatened. From 1811 to 1825, City officials recorded only 33,736 vaccinations. To reward parents who cooperated with this increasingly desultory campaign small coins and even pastries were offered to obtain serum from the arms of their children.14
3.3. Following the epidemic of 1797 in which widespread inoculation was resorted to for the first time, smallpox deaths were halved by means of, first, inoculation, then from 1804, arm-to-arm vaccination. The three greatest smallpox outbreaks of the nineteenth century (1804, 1829/1830, and 1840) struck down a few thousand children each, a minor fraction of the norm for the eighteenth century—notwithstanding the City’s continued demographic growth. From the late eighteenth century, each succeeding epidemic claimed fewer victims than the last, falling from over 14,785 deaths in 1779 to 7,147 in 1797 and 2,878 in 1840. City authorities understood the success of their efforts, explaining that in 1840 “the number of victims was much less than in prior invasions by the same illness.” Aid was organized block-by-block. Mass vaccinations were conducted with as many as 7,000 in a single week, as in 1839.15
4.1. Endemic smallpox and vaccination. But deaths were not reduced to zero, and in the 1860s, a concerted arm-to-arm vaccination campaign funded by the municipality was begun to contain the disease. The policy of providing vaccinations free of charge was now made general. Vaccinations were to be conducted by trained city health employees. Since in Mexico the vaccine was maintained by arm-to-arm vaccination, the human reservoir had to be replenished every ten days or so. Beginning in 1864 Luis Muñoz, chief vaccinator of the City, instituted a program of paying one peso to as many as twenty-five mothers per month for the privilege of vaccinating and subsequently harvesting “good vaccine granules” from their babies.16 Dr. Muñoz’s report for 1864 reveals that the authorities knew exactly what they were about and what the benfits of the campaign would be:
The vaccine, more widely extended than inoculation had ever been, diminished in a considerable way the number of people at risk (“aptas”), and at the same time removed the reservoir (“focos”) of contagion which was necessary for the disease to thrive.
4.2 Thus, in the words for Dr. Muñoz, “in these parts the great epidemics of smallpox were seen to recede or disappear, and only small epidemics remained”.17
4.3. This assessment was true only as long as vaccination did not languish, as Dr. Muñoz recognized. Unfortunately, in 1870, only 2,457 vaccinations were performed, and the number did not rise substantially in 1871. A killing epidemic got underway in January 1872 with 552 deaths in a single month attributed to the disease. The authorities immediately redoubled their efforts, vaccinating over 4,000 children in a few weeks.18 Vigilance continued with over 19,000 vaccinations in the following year, but the total for the entire decade still fell short of 100,000. In 1882, a municipal ordinance requiring mandatory vaccination of new-bornes by six months of age was enacted. The policy was instituted without public outcry or opposition—or full compliance, one must add.
4.4. Compliance was substantial, nonetheless, with over 30,000 vaccinations performed in the capital annually from 1894 to 1903.19 By the 1890s smallpox mortality in the City was pushed to insignificant levels. From 1892 through 1901 of 176,332 deaths recorded, only 0.9% (1,522) were due to smallpox.20 In 1903, compulsory vaccination was extended to the entire republic, and the following year deaths attributed to smallpox fell to 102 in the City.21 Thus, over the course of the nineteenth century, the disease was slowly transformed from epidemic to endemic, thereby greatly reducing smallpox mortality.
4.5. Smallpox remained in check as long as vaccination was nearly universal. In 1910, as revolution erupted on the northern border of the Republic, annual smallpox mortality in the City fell to a half-century low of 90. Then the figure began to rise, to 390 in 1911 and 429 in 1912. As warring and banditry worsened, migration increased and the instinct for survival overpowered charitable inclinations of both parents and public officials. In 1915, the last great smallpox epidemic in the City’s history erupted. Yet, it was a faint shadow of former bouts. From a weekly average of 10 cases (not deaths) over much of 1914, 18 cases were recorded in the first week of 1915, rising to 50 per week in March and 70 in April. Total deaths for the year surged by nearly one-third to 25,000, but smallpox accounted for only a tiny fraction of the increase. Hunger and typhus were the big killers in 1915.22 Three years later, when annual cause of death statistics for the City become available again, smallpox mortality had fallen to a mere 140 cases.23
5.1. Eradication. In the 1920s, the battleground against smallpox became the states and territories, because migrants now accounted for most deaths from the disease in the Capital. Justification for a centralized final assault against smallpox was inscribed in the Constitution of 1917, which provided for a National Public Health Department charged with improving conditions throughout the Republic. This provision finally lay to rest the helter-skelter vaccination policies of state and local health authorities, which prevailed throughout the nineteenth century. The effort was aided by a shift from the dangerous human to safer animal vaccines. A laboratory to produce animal-cultured smallpox vaccine had already been established in 1915, following a half-century campaign to replace the dangerous arm-to-arm method introduced by Balmis in 1804. Arm-to-arm vaccination—tenaciously supported by the Muñozes throughout their careers, and defended until 1907 by the Mexico City medical establishment—was finally abandoned in 1919. Note that this was a mere two decades after the use of human vaccine was made illegal in England.24
5.2. In 1931, there occurred a deadly surge in smallpox, with 15,003 fatalities reported for the entire republic. With this tripling of the annual average during the late 1920s, a new strategy was instituted. Mobile vaccination brigades were formed to be on constant alert to encircle and suffocate outbreaks before a more generalized eruption could spread. The goal became to eradicate smallpox from the entire nation, not by attempting the impossible task of vaccinating everyone, but rather focussing efforts on every instance of the disease, encircling all cases by means of quarantine and vaccinating all those who may have come into contact with the infected. Dr. Miguel E. Bustamante, who developed the strategy, commanded a bold troop of young doctors and nurses to respond to the first signs of an outbreak. Over the first ten years of the program, total deaths due to the disease declined by 90%, to 1,341 in 1940 for the entire Republic.25
5.3. If the national effort was to succeed, an effective quarantine along the nation’s borders was also required. With the disruption of World War II, millions of Mexican guest workers migrated to labor-short factories and fields in the United States. Annual smallpox fatalities in Mexico doubled and then tripled, reaching 4,115 in 1942. In the capital, deaths rose from single digits to 64 in 1943—indirect casualties of war. Nevertheless, by war’s end, Bustamante’s mobile brigades had regained their effectiveness, and fatalities for the entire nation plunged to 54 in 1951. From that year, no further smallpox deaths have ever been recorded in Mexico City. In 1954, the last smallpox fatality in the entire republic was reported, two decades before it was extinguished from the planet.26 Meanwhile the Mexican national public health bureaucracy had grown enormously and its mission expanded to battle yellow fever, typhus, malaria, and similar threats to the general welfare.
6.1. Charity. Over the centuries the battle against smallpox led to new, more charitable attitudes toward public health and a shift from programs to alleviate suffering to prevention, and ultimately eradication, of the disease. The struggle was prolonged not for a lack of charitable impulses—on the contrary enormous efforts were made from the first years of Spanish rule—, but for a lack of effective means. Five phases may be discerned in this struggle: 1520, native methods; 1538-1779, curative; 1797, preventive by quarantine and inoculation; 1804-1882, reactive vaccination; 1882-1931, proactive vaccination; and 1931-1954, eradication.
6.2. The idea that ancient Mexico was exempt from severe epidemics, and thus had no notions of care against disease, is no longer sustainable. Pre-columbian Mexico was no paradise, as attested by the panoply of gods, remedies, incantations, and expressions for sickness, including pestilence, in the ancient Nahuatl language, iconography, pictographs and written records. Pestilence is recorded in year signs of the codices, such as the Telleriano-Remensis, but annals, narrative texts written down from oral accounts, provide a great many more details. The Annals of Cuauhtitlan are particularly informative on these matters because they report on a region, rather than a single town (altepetl), and are rich in apocalyptic events. “Depopulated because of pestilence” read the annals for five places (variously, towns, districts, or provinces) in the half-century prior to the Spanish conquest.27 Typhus, diphtheria and influenza have been suggested as possible causes.28
7.1. Nahua treatments. The first phase of the battle against smallpox was limited to the outbreak of 1520, when the Nahua sought to fight the disease with conventional indigenous treatments for fevers and pustules. Only native remedies were available in Tenochtitlán because Spaniards, who might have provided aid in the same way that captured Christian crossbow-men were used to shoot arrows at their comrades, had already fled or were dead. For the Nahua, quarantine was a completely alien notion, but treatment or care for skin diseases was not. There are no sources to tell us exactly which remedies were attempted, but the exceedingly thorough historian of the conquest, Hugh Thomas, portrays a plausible scenario:
A special fortune-teller, a tlaolchayauhqui, was asked, as usual, to determine the cause of the new disease by observing the pattern of grains of maize or beans on a white cotton cloak. On this occasion he must have been baffled. The old remedies must have been tried: “The core [of the sore] is removed with a pine resin and squashed black beetles are spread there”.29
7.2. What astonished the Nahua was not the failure of conventional remedies but the absence of care, not for lack of a caring impulse, but for a lack of caregivers. The testimony is direct, descriptive, and despairing:
Before the Spaniards appeared to us [again], first an epidemic broke out, a sickness of pustules. They could no longer walk about, but lay in their dwellings and sleeping places, no longer able to move or stir. They were unable to change position, to stretch out on their sides or face down, or raise their heads. And when they made a motion, they called out loudly. The pustules that covered people caused great desolation; very many people died of them, and many just starved to death; starvation reigned, and no one took care of others any longer.30
7.3. The accompanying pictures, drawn by native artists a half century after the event, seemingly contradict the text. They show a native woman caring for five prostrate, pockmarked adults. The ill show great pain, despair, or resignation as they lie on petates of plaited rushes and pillows of folded cotton mantas, wrapped in large cotton blankets. Portions of upper torsos and faces are visible. One is crying out, attempting to pull herself from the mat. A second, seemingly near death, is tightly wrapped from neck to feet, but the ominous signs of the pocks are visible on her toes. The caregiver, with grave assurance, tenderly succors a third with her bare hands and soothing voice. Unfortunately her speech goes unrecorded.31
7.4. Perhaps the written testimony that “no one took care” should not be taken literally. Or perhaps the pictures reflect care giving as practiced in a subsequent bout with the disease, such as in 1538. What is certain is that care changed as natives quickly adopted Spanish cultural techniques, honed by centuries of experience with the pox. Natives were taught to prepare themselves for the eruption of the pustules. Once erupted, they were comforted, given water, food, and blankets, and cautioned not to bath or scratch until the scabs had fallen away.32
8.1. Christian charity. Practices of Christian charity were also introduced from earliest times, providing not only the sacraments, but also water, food, care and solace. Sahagún observed that, since an entire household would often fall ill at a stroke, “there was no one who could give even a jar of water . . .and knowing this the religious walk house to house providing confession and consolation.” In the matlazahuatl epidemic of 1576, Viceroy Martin Enriquez encouraged Spaniards to distribute food, also by going house to house with no suggestion of distinction by race or reputation, class or color.33 Acts of charity are confirmed by annals, authored by anonymous native intellectuals. The most prolific is for Tlatelolco, twin city of Tenochtitlán, with four references over the sixteenth century of aid campaigns by religious and secular officials, two where food was given “in our homes,” including the provisioning of meat on one occasion.34
8.2. These annals also reveal the beginnings of grand religious processions and public prayer. The procession of the Virgin of Remedios, first recorded in 1575, became favored for smallpox epidemics in Mexico City.35 Her intercession was sought throughout the seventeenth and eighteenth centuries. In the last great outbreak of the colonial era, 1797-98, three processions were organized: la Virgen de los Remedios (week 10 of the epidemic), Santísimo Christo Renovado de Santa Teresa (week 11) and finally, la Virgen de Guadalupe (week 13), for which the Viceroy ordered an eight day holiday.36 The processions in 1797 came as the disease peaked and then declined as shown in Figure 1.