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Kala-azar was once a scourge of the Bengal Presidency of British India, rampant in the areas along the Ganga and Brahmaputra, as a 2021 review in Tropical Parasitology describes it. The drug that changed that was made in Calcutta by an Indian doctor who had first trained as a chemist. This post covers what Upendranath Brahmachari did, the chemistry behind his drug, and what a student can learn from how he worked.
What is kala-azar?
Kala-azar is the common name for visceral leishmaniasis. The WHO fact sheet on leishmaniasis describes it as a disease caused by protozoan parasites of the genus Leishmania, passed on by the bite of infected female phlebotomine sandflies. It causes irregular fever, weight loss, an enlarged spleen and liver, and anaemia, and WHO says it is fatal in over 95% of cases if left untreated. Most cases today occur in Brazil, east Africa and India.
The parasite itself was found only in 1903. That review, by Saha, Chaudhury and Maji, records that William Leishman and Charles Donovan found it independently, and that Ronald Ross named it Leishmania donovani. You can read about Ross's own work on another parasite in our profile of Ronald Ross and the mosquito link to malaria.
Who was Upendranath Brahmachari?
The same article gives his birth date as 19 December 1873 and says he grew up in Jamalpur, Bihar, where his father was a railway doctor. He took a BA with honours in mathematics and chemistry from Hooghly College in 1893, then a master's in chemistry from Presidency College, Calcutta. Only then did he switch to medicine, earning an MB in 1900, an MD in 1902 and a PhD in physiology in 1904 for work on haemolysis, the breaking of red blood cells.
He taught at Dacca Medical School, then spent about twenty years at Campbell Medical School in Calcutta (now Nil Ratan Sircar Medical College), before moving to Calcutta Medical College in 1923. He died on 6 February 1946. Nature published an obituary by L. Everard Napier that year.
How did he find a better drug?
Before his work, doctors treated kala-azar with tartar emetic, a potassium antimony salt given by vein. The 2021 article notes that it had a narrow safety margin, and that long courses brought heart and liver problems. Brahmachari first tried related antimony salts and colloidal antimony, but these were hard to prepare and store.
His idea came from another disease. Paul Ehrlich had shown that atoxyl, an organic arsenic compound, worked against sleeping sickness. Brahmachari asked what would happen if he kept the organic part of that molecule and swapped the arsenic for antimony, the element just below it in group 15 of the periodic table. The result, made in 1920 in a small room at Campbell Hospital, was urea stibamine: the urea salt of para-amino phenyl stibnic acid, a pentavalent antimony compound. In later writing he recalled working there at night by a kerosene lamp, in a room without a gas point or a water tap.
How well did urea stibamine work?
The Tropical Parasitology review credits urea stibamine with a cure rate above 90% and few side effects. A 2024 review in Cureus by Kawalkar and colleagues reports that, by 1933, the Director of Public Health in Assam recorded 328,591 patients treated with it, and that the drug was also used in Greece, France and China. Brahmachari also described a skin condition that appears in some patients after kala-azar, now called post-kala-azar dermal leishmaniasis; he published on it in 1922.
He was knighted in 1934, according to the Cureus review; the Tropical Parasitology review also records the knighthood. The Nobel Prize nomination archive lists six nominations for him in Physiology or Medicine: one in 1929 and five in 1942. He did not receive the prize.
Why should a student care?
Two school-syllabus ideas meet in his story. In biology, kala-azar is a protozoan disease with an insect vector, like malaria; our guide to human health and disease covers how such diseases spread. In chemistry, the reason his substitution was worth trying is periodic trends: elements in one group share outer-shell structure and form related compounds. If either idea feels shaky, the Fermi Concept Library covers every concept in physics, chemistry, biology, mathematics and computing, each with its own lesson.
What can a student take from how he worked?
Keep your first subject. He trained in chemistry before medicine, and that is what let him think about a drug as a molecule to redesign. Subjects you study now can become your edge later.
Borrow a working idea. He did not start from nothing. He took a compound that worked against one parasite and changed one element. When a problem is new, ask which solved problem it resembles.
Fix the known flaw. Tartar emetic worked but was dangerous. He aimed at a specific weakness, not a vague improvement.
Work with what you have. A room without running water did not stop him. Your setup does not have to be perfect for real work to start.
Look up arsenic and antimony in the periodic table tonight, and list two other pairs of elements in one group that form similar compounds.
