An Interview with Manuel F. Varela and Ann F. Varela—Who “Cured” Leprosy?—Alice Ball!

Jan 2, 2022 by

Alice Ball

I work and work and still it seems that I have done nothing.”

—Alice Ball

Michael F. Shaughnessy

1) First of all, please enlighten us about leprosy. What is it? What does it do? Moreover, why is it so devastating?

The affliction of leprosy, also called Hansen’s disease, is a severe, debilitating infectious disease. The infection is caused by a slow-growing bacterium called Mycobacterium leprae. See Figure 1. The discoverer of the causative bacterial agent was Gerhard Hansen, who isolated the microbe in 1873. The bacterium has a Gram-positive cell wall with a high mycolic acid content, producing a thick waxy-like substance on its surface. The bacterium stains rather weakly with Gram stain. Thus, acid-fast staining is used to diagnose the illness by identifying the bacteria in clinical samples taken from skin lesions of patients. Because the mycolic acid takes an unusually long period to be produced for incorporation into the cell wall, the bacterium grows slowly. This slow growth is worth waiting for the microbe because the mycolic acid protects it from phagocytic destruction by macrophages. The Mycobacterium leprae microorganism grows while residing inside a phagocyte—the very immunity-based protective host cell whose purpose is to destroy invading bacteria. The infectious agent evades the immune system because the microbe survives and multiplies its cells inside a host cell macrophage. The leprosy ailment is generally manifested in two distinctive forms, depending on the magnitude and type of the immune response against the bacterial antigen.

Figure 1. Histology showing lepromatous leprosy. The epidermis is atrophied with flattening out of rete ridges, a clearly visible acellular area – grenz zone (prominent finding shown here) and below which show foamy macrophages filled with Mycobacterium leprae bacteria (seen in the inset as red bacilli, using Fite’s acid-fast stain).

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Lepromatous leprosy, also called multibacillary Hansen disease, is severe, characterized by a visible skin rash with abnormally red (erythematous) nodules, papules, and macules. The skin and other tissues are extensively damaged, frequently causing severe disfigurements, plaques, and abnormally thick skin layering. If untreated, the nodular tubercles on the face and fingers can destroy their features while causing permanent damage throughout other body areas. Often, disfigurement can be used for diagnosis. The disease can also be accompanied by nasal mucosal involvement, and neurological symptoms may arise, such as sensory loss. This lepromatous form of leprosy is caused by a robust humoral immunity (antibody production) but a weak T-cell immune response, thus permitting the invading bacteria to grow in the skin, neurons, and the mucous membranes about the eyes, throat, and nose. Gradually, these infected tissues are damaged as the bacteria grow and infiltrate further into a person’s tissues. This form of leprosy is the most infectious of the two. See Figure 2.

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Figure 2. Tuberculoid leprosy of the leg.

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In medical journals of the 19th century, the disfigurement caused by the lepromatous form was described as hideous and “the most terrible disease that afflicts the human race.” The devastation you speak of refers to the severe pathological effects on an individual patient and the public stigma implemented upon those afflicted. In a few notably historical cases, patients would be isolated or quarantined in so-called “leper colonies” segregated from the remainder of the healthy population. It was institutionalized ostracization on a widespread scale. Even the Bible mentions the separation of leprous individuals in isolated colonies.

In Medieval times, lepromatous patents were made to carry clappers (bells) to attract public attention and warn healthy populations that a “leper” was nearby. The pejorative term leper used to describe leprosy patients is no longer used clinically. Some even object to the term leprosy. However, we mention it here for continuing educational and historical purposes, but our readers should be aware that the term may be outdated in favor of Hansen’s disease.

The second type of disease is called tuberculoid leprosy. This form is also called paucibacillary Hansen disease. The ailment is characterized by a relatively vigorous T-cell immune response to the infecting bacteria. Activation of the T-cells by the bacterial antigens results in an induction of cytokines, which recruit macrophages, a type of white blood cell. This macrophage-mediated phagocytic process clears the leprosy-causing bacteria. The symptoms of tuberculoid leprosy include poorly pigmented skin lesions consisting of macules or plaques, which have flat centers with raised borders. Loss of sensation within the skin lesions is a diagnostic feature.

Epidemiologically speaking, leprosy has been a problem in regions of the world where effective therapies are unavailable. These areas have included Brazil, Indonesia, and India primarily. In the U.S., leprosy is endemic in southern states, like Texas and Louisiana, where armadillos are reservoirs and vectors to humans of severe lepromatous disease. Interestingly, the Mycobacterium leprae bacterium has never been cultured on Petri dishes in the laboratory with any known media. Instead, Armadillos have been used to maintain the bacteria.

The traditional modes of leprosy disease transmission include person-to-person contact, a respiratory route, and a combination of the two in which an individual’s skin makes contact with respiratory secretions from an afflicted individual. The fourth mode of transmission can involve contact of an individual’s skin with wound secretions from a leprosy patient.

Surprisingly, a leprosy infection is not easily transmitted between humans. Instead, prolonged interaction with an untreated infected individual is necessary to infect another healthy human host. It is likely that because of the causative agent’s inability to proliferate quickly, the prolonged interaction with a leprosy patient is required for infection to take hold of another human.

Historically, leprosy has been a scourge in various human populations. Ancient Chinese, Indian, and Egyptian literature as far back as 600 BC have described the ailment. As recently as the 1980s, leprosy has been a worldwide prevalence, with cases numbering in the millions.

As mentioned earlier, this infectious disease is uncommon in places where adequate treatment is available. The lepromatous form of leprosy can be treated with an antibiotic called clofazimine, which inhibits bacterial DNA replication, preventing the growth of the microbe. See Figure 3. Incidentally, clofazimine has recently been found to help patients with multiple sclerosis, psoriasis, and diabetes (type 1). Clofazimine blocks a calcium update system that is needed to mount an autoimmune response. Lastly, a vaccine, BCG (Bacillus of Calmette and Guérin), is available but not recommended for the general population.

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Figure 3. Molecular model, ball-and-stick, of clofazimine.

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The antimicrobials rifampicin and dapsone have been used to treat tuberculoid leprosy. Rifampicin is an inhibitor of RNA synthesis, which prevents the bacterium from using any RNA to undergo protein synthesis and, thus, the bacteria cannot grow. Dapsone is an antimetabolite that inhibits the enzyme dihydropteroate synthase, thus preventing folic acid production, inhibiting metabolite production, like nucleic acids and amino acids. Antimicrobial treatment can last two years minimum and may last a lifetime in some Hansen disease patients.

2) Kalaupapa is an island in Hawaii—which for years housed those afflicted with leprosy. What are any historical facts about this place?

In 1866, King Kamehameha V of the Hawaiian Kingdom inaugurated an Act to “Prevent the Spread of Leprosy,” establishing a prison-like colony for patients who had Hansen disease. In the years before, much fear of acquiring the contagion was paramount, and many wondered whether exposure to the afflicted would result in worldwide disease incidence. An increasing number of people feared a leprosy pandemic. Those who contracted the affliction were considered dangerous spreaders of leprosy, and without an available treatment, the sufferers were believed to be incurable and, thus, a lost cause. Consequently, all over the world, patients with leprosy were increasingly segregated into isolated locales, like offshore islands.

The new “leper colony” that was legislated by King Kamehameha V at Hawaii was, thus, meant to isolate lepromatous patients from the rest of the healthy populations. Individuals who had the disease were rounded up and forced to reside in the leper colony on a piece of land called Kalaupapa, also called Kalawao or mai ho’okawale, for “the separating sickness,” on the Island of Molokai, in Hawaii. See Figure 4. In many cases, inhabitants of the colony were driven from their homes, leaving behind family and all belongings, and sent to Kalaupapa or Kalawao, another colony of leprosy “prisoners.” The Kalaupapa locale was a geographical prison, with the Pacific Ocean facing three sides of the area and a 2,000-foot cliff facing the fourth side of the colony. Kalaupapa was a place that was difficult to reach and, notably, difficult to leave.

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Figure 4. The Kalaupapa leper colony in 1905. 

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In over 80 years of its operation, an estimated 8,000 lepromatous occupants lived in horrible conditions. The colony was once called the “pit of hell, the most cursed place on Earth,” by the famous author Jack London. The lepromatous inhabitants called it the “living death.” It seemed a grave situation for the afflicted colony members, a hopeless secluded place to die from leprosy. Various clergy who ministered at the colony would recall how heartbreaking the whole situation was at Kalaupapa. In one story, a priest and missionary Jozef De Veuster, known colloquially as Father Damien, ministered heroically at a nearby leper colony at Kalawao and would succumb to the illness himself and die from it at age 49 in 1889.

In the early 20th century, Harry T. Hollmann, a physician working at Kalihi Hospital in Honolulu, encountered several Hansen disease patients from Kalaupapa. Hollman had become aware of the Chaulmoogra oil, which had mixed results in treating leprosy. Namely, Hollmann needed a scientist with a background in chemistry and pharmacology. Alice Ball had the expertise and the educational credentials. Hollmann actively recruited her to take up the task of finding a suitable means for using chaulmoogra oil to treat leprosy cases, like those housed at Kalaupapa.

3) Now, Alice Ball, the first African American to earn a graduate degree at the College of Hawaii, enters the picture—when was she born, and what do we know about her early life?

James P. Ball, Jr., and Laura Louise (Howard) Ball welcomed their first daughter, Alice Augusta Ball, into their Seattle, Washington home on July 24, 1892. Ball’s mother was a photographer, and her father was employed as a lawyer and also as a photographer. Alice had two older brothers, Robert and William, and a younger sister, Addie. Her grandfather, James Ball Sr., was a famous photographer and one of the first African Americans in the United States to learn the art of daguerreotype. The family enjoyed a comfortable existence as far as income was concerned. In 1903, they relocated to Honolulu, hoping that James Ball Sr. ’s arthritis pains would be eased by the balmy weather. Regrettably, James Ball Sr. died before long, and the family returned to Seattle.

Ball was a standout student in the graduating class of 1910 at Seattle High School and obtained a few graduate degrees from the University of Washington and the College of Hawaii. Ball also co-authored a 10-page paper on benzoylations in ether solution that was published in the Journal of the American Chemical Society, which was extraordinary for an African American woman at this time.

After earning undergraduate degrees in pharmaceutical chemistry in 1912 and pharmacy from the University of Washington in 1914, Alice Ball transferred to the College of Hawaii (now the University of Hawaii) and turned out to be the first African American and the very first woman there to graduate with a master’s degree in chemistry in 1915. At the age of 23, she was offered a teaching and research position there and became the institution’s very first woman chemistry instructor.

Catastrophically, Ball died on December 31, 1916, at the young age of 24, in a laboratory accident. It is thought that she could have inadvertently inhaled chlorine gas. During her short-lived existence, she did not get to see the full impact of her discovery. Furthermore, in the wake of her death, the president of the College of Hawaii, Arthur Dean, apparently continued Ball’s research without giving her credit for the discovery. Dean dared to claim her breakthrough for himself, and called it the “Dean Method.” Unfortunately, it was routine for men to take the credit for women’s discoveries and Ball was an unfortunate prey of this practice.

4) Now, another strange word—the chaulmoogra tree—oil from this tree treats leprosy. Enter Alice Ball, and what were her contributions?

Alice Ball discovered an effective means of injecting chaulmoogra oil into leprosy patients. When Ball entered the picture, Leprosy patients had been kept in segregated colonies where a purported “treatment” was chaulmoogra oil. It seemed the only source of relief from the affliction was the thick sticky oil extracted from the seeds of the chaulmoogra tree. However, prior attempts to treat leprosy with the chaulmoogra oil were successful only in some cases but not others.

Unfortunately, working with the chaulmoogra oil substance was problematic. First, this tree seed oil was insoluble in water-like solvents. Injection of the chaulmoogra oil itself was painful to the patient. If chaulmoogra oil would ever be injectable into a leprosy patient, the substance’s ability to be dissolved in water or a water-based solvent or buffer was required. The human body is a water-based lifeform, and anything therapeutic, such as potentially disease-alleviating oily tree seed substances, likewise needed to be aqueous. Otherwise, the seed oil from the chaulmoogra tree would not be able to treat leprosy effectively. The chaulmoogra oil’s propensity for stability in more oil was a barrier to an effective leprosy treatment. Thus, the chaulmoogra oil, with its lipid-soluble character, was an enormous problem.

A second problem with the chaulmoogra oil was that it caused enormous pain in the stomach of patients if the oil was taken orally. The oil was probably digested into useless end-products, probably converted into clinically unavailable biochemicals, and somehow unable to improve pathological skin conditions. Nevertheless, a significant side effect was nausea, which meant that as an oral treatment with the consistency of thick honey, the chaulmoogra oil was too harsh a treatment.

Thirdly, if patients applied the chaulmoogra tree seed oil on their skin lesions, it did not seem to work to alleviate the leprosy ailment reliably. The causative agent bacterium was deep in the aqueous tissues of the patient. If the chaulmoogra oil was rubbed onto the skin, it could not reach the microbes deep within the patients’ tissue.

Therefore, a form of chaulmoogra oil was needed that could be injected, bypassing the nausea of the gastrointestinal tract and the skin’s external barrier. With expertise in the chemistry of plant material, Alice Ball would change the direction of the dreadful lives that leprosy patients were living in at the time.

5) Keyword—viscosity—as a chemist—what was Alice Ball’s contribution?

In a word, the chaulmoogra oil had an enormously complex viscidness, and Ball solved this viscosity problem. As we mentioned above, the potential leprosy disease-curing chaulmoogra oil was too viscous. This oil, extracted from the chaulmoogra tree, had the texture of thick honey, a property that was unhelpfully not dissolvable in water. In its oily lipid-loving form, the chaulmoogra oil had posed barriers against its clinical use in treating leprosy patients, who were consigned to exist under dreadful conditions in isolated leper colonies.

The viscosity problem of the chaulmoogra oil and leprosy, up to that time before Ball’s involvement, had perplexed both physicians and scientists alike. The viscosity problem had puzzled Hollmann, who agonized about it and who had now enlisted Ball to address the puzzle. In graduate school, Ball had acquired all of the necessary expertise to solve the chaulmoogra oil brainteaser.

Ball’s master’s degree in science concerned isolating the active chemical ingredients from the kava plant (also called ava or vakona) known by its scientific species name Piper methysticum. Ball harvested the rhizome roots of the plant, chopped them up with a meat chopper, and dried the material in a vacuum oven or under the sun for two days. Ball then made a fine powder of the dried plant material and conducted a chemical extraction procedure with the chemical ether using ice around the extraction coils to prevent the ether from billowing away.

Ball extracted methysticin from the plant powder. She also removed free acids by vigorous shaking of the solution that contained various carbonates and sodium hydroxide. She isolated the acids with a dilute hydrochloric acid solution and vigorous shaking. The remaining plant extract material was treated with a solution of alcohol and potassium hydroxide. Ball then converted the esters in the extract to alcohol and a metal salt using heat and alkaline hydrolysis; a process called saponification, which converts an oil or lipid, e.g., triglyceride, into a type of soap. See Figure 5. Soaps are basically the sodium or potassium salts of lipid-based substances. Ball then conducted a distillation process to remove the alcohol and extraction to remove radical chemicals.

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Figure 5. Saponification, a common process of producing soap.

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Next, Ball conducted various steps to remove the extraction reagents from her mixture of plant chemicals. She filtered various forms of the plant material using a suction pump and washing the precipitate with water. Ball added hydrochloric acid and boiled the so-called barium resinate to free up the resin acid. She removed the acid by shaking it out using ether. She removed the ether by filtering, then distillation, and drying the material, leaving a substance she called barium acid. Likewise, Ball isolated an iron acid. The material remaining after isolation of her crystalline methysticin was called total resins. The acidic resins were called total free acids.

The master’s thesis project, when completed and approved on May 14, 1915, by officials at the College of Hawaii, provided Ball with a plethora of chemical methods that were critical for examining plant chemicals. The scientific expertise possessed by Ball was just the sort needed to solve the chaulmoogra oil problem. Using her newly acquired chemical expertise, Ball prepared ethyl ester derivatives out of the fatty acid active agents within the chaulmoogra oil.

6) In 1918—an article in the Journal of the American Medical Association (JAMA) reported on the results of 78 patients who were discharged—due to Ball’s chaulmoogra oil concoction. How do we treat leprosy today, or does it even occur?

In 1915, Ball would change the scientific history of leprosy. She solved the puzzle that confounded generations of scientists regarding effective treatment for the disfiguring agent. The primary problem at the time was a lack of an injectable blood-soluble watery substance from the chaulmoogra tree that could ameliorate the ill effects of leprosy. There was a secret cure, an oily, thick chemical, in the tree. The problem was that the secret chemical cure was insoluble in the body. An answer was needed in which the chaulmoogra oil could be altered somehow to make it dissolve in an aqueous medium. Many investigators were working on the aqueous solubility problem and coming up short. Alice Ball used her chemistry expertise, partially described above, to solve the solubility conundrum that chaulmoogra oil posed. Her solution was to produce an ethyl ester derivative of the fatty acids in the chaulmoogra tree in the lab. Ball’s secret chemical was an ester compound of alcohol that was made from the chaulmoogra lipid.

First, Ball prepared large amounts of chaulmoogra oil as a starting substance for making derivatives. Next, she used an alcohol-based potash substance to saponify the oil by distilling the alcohol within the oil during the saponification. Thus, Ball had succeeded in converting the oil into soap! This discovery is reportedly the first time in history that anyone had ever saponified the oil of the chaulmoogra tree. However, this success was just the beginning. Ball needed to use her unique gifts and talents to solve the mystery of the leprosy-treating substance.

Next, Ball added a large amount of water and a small amount of acid to her newly made chaulmoogra soap. She immediately noted that the fatty acids of the chaulmoogra oil separated from the rest of the tree substance. This fatty acid separation was another first, and it was Ball who accomplished it. She then “washed” the fatty acids with hot water, dried them, and managed to dissolve the chaulmoogra substance in alcohol!

This feat, i.e., putting chaulmoogra fatty acids into alcohol, was another first. Occasionally, a lipid-soluble substance can be dissolved in alcohol, which represents a step closer to dissolving in a water-based solvent. This alcohol solubility step was a breakthrough in the history of chaulmoogra oil chemistry.

Ball placed her fatty acid-alcohol mixture into a cold refrigerator overnight. The following day, Ball found that the fatty acid component turned into a large mass of crystals. She removed these fatty acid crystals by filtering, another critical step astutely conducted by the expert chemist. Next, Ball repeated the crystallization-filtration steps several times, producing a new substance called chaulmoogric acid, as seen in Figure 6.

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Figure 6. The S-enantiomer structure of chaulmoogric acid.

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Then she produced a series of compounds from the chaulmoogric acid. One of these compounds was called “Preparation A” by Ball. The new chemical A consisted of an ethyl ester of the chaulmoogric acid. “Preparation B” was produced from the so-called mother liquors of Preparation A and contained the fatty acids remaining after the Preparation A material was made during the first crystallization-filtration step. Subsequent repeated crystallization and esterification steps made the preparation B material. This B substance also contained ethyl esters of acid of alcohol using chaulmoogric acid but was independent of the first separation conducted above.

Ball then made Preparation C. This C substance was produced using Preparation A as a starting point. She converted the soluble acids of substance A into soaps containing lead by making potassium soaps, precipitating into a solid with lead acetate, drying the material, adding ether, shaking the mixture, and leaving the shaken material to stand overnight. In the morning, Ball filtered out the solid material from the mixture, producing a lead soap. She added ether, hot water, acetate, and hydrochloric acid. These chemicals worked to separate the lead from the soap, and she recovered two forms. Each of these differed in their ability to dissolve their lead salts in ether. She esterified both fractions and measured whether their lead salt versions could be dissolved in ether. The first fraction was a soluble lead salt solution in alcohol, i.e., a lead salt, that she called “Preparation C.” The second fraction was insoluble in ether, which Ball called Preparation D, i.e., an ether-insoluble “lead soap.”

All four chemical fractions, A, B, C, and D, contained various forms of ethyl ester derivatives of the fatty acids in the bulk of the chaulmoogra oil from the original tree. These ethyl esters proved to be the very agents that could be injected into leprosy patients and provide novel relief of their ailments, a first in the history of this infectious disease. Before Ball could publish her new method, she died from an unfortunate accident at 24 years of age.

7) Sadly, like Marie Curie and others, Alice Ball gave her life for science and for the cause of helping others. She inhaled some chlorine gas—what happened to Alice Ball?

At the age of 23, Ball solved the mystery of the solubility problem with chaulmoogra oil, and at the age of 24, Ball was dead. It seems that the circumstances of Ball’s death are as mysterious as the solubility question that had been plaguing chemists worldwide.

Shortly after Ball made her groundbreaking discovery, inventing a novel and complicated chemical method for dissolving the gooey chaulmoogra oil into a potentially injectable form for critically ill leprosy patients, she took ill herself. The labor-intensive laboratory work involved in inventing her Ball method of ethyl ester preparations had been an exhausting process. Hence, Ball left the lab in Hawaii and returned to her family’s home in Seattle, where she died on the last December day of the year 1916.

Various possibilities have been put forth to explain the cause of Ball’s death. Some sources declared that she had succumbed to chlorine poisoning due to her lab work, where the ventilation system was thought to be poor. Indeed, much of her ethyl ester work with the chaulmoogra fatty acids required various hydrochloric acid solutions, some of which can be noxious. Another source stated that Bell was teaching a course in Hawaii and inhaled the chlorine gas during a lab demonstration on using a gas mask. While the specific circumstances are unclear, it is clear that inhalation of the chemical’s fumes of hydrochloric acid or chlorine can be pathological and even lethal if a large quantity or concentration is involved. One last source, Ball’s official obituary, states that her death was due to tuberculosis. Some published reports refute this claim about tuberculosis, also known as the Consumption at the time, as the cause of Ball’s death. These detractors argue that Ball did not have enough time to suffer a complete infectious disease course. Tuberculosis can take many months for a patient to suffer the ill effects and die, and Ball did not seem to have had a chronic case. These same detractors put forth evidence—her M.S. graduate degree photograph, shown at the beginning of this chapter—where Ball appears as a healthy, robust individual and not necessarily a person with consumptive appearance.

8) What last recognition can we give to the woman who succeeded again, apparently, against all odds?

After her death, Hollman would use Ball’s newly developed chemical method to treat tuberculosis and leprosy patients with ethyl ester derivatives of the chaulmoogra tree fatty acids. He was successful, and the treatment would be used for at least another generation of leprosy patients until antibiotics could be widely used. Ball’s premature death, however, had repercussions.

One consequence was that another investigator would steal the credit for Ball’s discovery. The story is told that upon Ball’s death, the then departmental chair, Arthur L. Dean, would be eventually promoted to president of the college, and he would continue Ball’s work but, at best, neglect to give her proper credit for her method, and at worse, steal her work and take full credit of the ethyl-ester fatty-acid derivative of chaulmoogra tree oil discovery for himself.

Another repercussion was that for many decades her contribution was all but forgotten. Even when Hollman wrote, in 1922, about “Ball’s method” for producing the ethyl ester derivative of the chaulmoogra fatty acids, giving her full credit in scientific detail, the proper attribution of credit to Ball was nevertheless ignored and, thus, no longer historically remembered. This injustice has lasted almost 90 years. In modern times, Ball’s contribution to the early successes in treating leprosy is increasingly being recognized. Several tributes and book chapters concerning Ball and her work are now available. It is now definitively established that Ball has left a legacy of the significance of proper scientific attribution and adversity’s historical consequences.

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