Darwin’s Disease

Experimentally, Darwin allowed vinchucas to draw blood from his finger and marveled at the dexterity of their proboscises. Some scholars have interpreted this to suggest that he became infected with T. cruzi, which would explain his semidebilitated state five years after the Beagle landed.[6]Several weeks after being bitten, Darwin wrote in his diary for April 9, 1835: “From this day till I reached Valparaiso, I was not very well & saw nothing & admired nothing” (Keynes 1988:323). Darwin reached Valparaiso on April 17. The incubation period corresponds to the lead time for acute Chagas’ disease, but nine days is relatively short for its duration.

A second indication is that several years after the vinchuca bite Darwin began suffering a complex of symptoms from an undiagnosed chronic illness. Chagas’ disease gradually develops into a chronic phase, what has been called an intricate lifelong minuet that is danced by the parasite and the host’s immune system (Goldstein 1989). This could explain Darwin’s illness: nonspecific symptoms of increased parasitemia such as malaise, fever, fatigue, and decreased energy when the immune system was down. Advancing age, periodic illnesses, psychological stress, and exhaustion could certainly have weakened Darwin’s immune system, which was necessary to keep T. cruzi at bay.

At the age of thirty‑three, Darwin’s period of great physical activity was over. Darwin logs continual, nagging complaints in his diaries from 1839 until his death in 1882 that indicate a persistent and not readily diagnosed problem:

the smallest exertion is most irksome… periodic vomiting… I was almost quite broken down, head swimmy, hands trembling and never a week without violent vomiting… very weak… only able to tolerate short walks… headaches… fatigued… oppressed.. .flatulence… prolonged spells of daily vomiting of “acid & slime,” fright… sinking sensation… trembling… shivering… and fatigue. (Darwin, in Goldstein 1989)

These symptoms waxed and waned throughout Darwin’s life and greatly curtailed his professional activities, travels, and social life. In 1882 Darwin developed myocardial degeneration which progressed to angina pectoris; he died that year.

Some facts, however, work against the idea that Darwin died from Chagas’ disease. Darwin’s illness in many ways is not characteristic of Chagas’ disease. Darwin never mentioned the first signs of the acute phase, development of a chagoma, a rash consisting of tiny red spots, fever, and spleen and heart problems. However, the majority of afflicted adults (60 to 70 percent) do not suffer symptoms of the acute phase. Ignorance of this factor remains a problem because many infected individuals with chronic Chagas’ disease claim they are not infected since they did not suffer symptoms of the acute phase. Chagas’ disease is frequently asymptomatic until years after the initial infection. The observation that Darwin reported no high fever is not sufficient in itself to rule out Chagas’ disease.

Exhibiting limited knowledge, Browne (1995:280) refers to Chagas’ disease as a South American sleeping sickness, with the implication that because Darwin did not suffer a fever typical of African sleeping sickness he did not have Chagas’ disease. American trypanosomiasis (Chagas’ disease) and African trypanosomiasis (African sleeping sickness) are both caused by trypanosome parasites: one by Salivaria, which lives in the saliva of its vector insect, and the other by Sterecoria, which lives in the feces of its vector insect. The difference between these parasites is that African trypanosomes remain in the blood and cause recurring fevers that exhaust the immune system; in contrast, American trypanosomes enter the neuron cells and frequently do not trigger immediate action of the immune system. American trypanosomes also reenter the blood.

Although Darwin’s symptoms did not indicate heart disease until he was seventy‑one, a relatively long life for the nineteenth century, he could have suffered subtler degrees of myocardial dysfunction, associated with T. cruzi, causing many of the complaints listed in his correspondence (see Adler 1959; Medawar 1964; Goldstein 1989). This debate has brought attention to Chagas’ disease, sometimes referred to as Darwin’s disease, and its diffuse nature and complex symptoms. Some hope that Darwin’s body will be exhumed and its tissues examined for T. cruzi.