Smallpox, Syphilis and Salvation

by Sheryl Persson

  Today, despite a vaccine being available, for which we are indebted to Emil von Behring and Shibasaburo Kitasato, both generalised tetanus and the neonatal form remain a significant public health problem in developing countries where the mortality rate for people contracting tetanus can be as high as 60 per cent, although on average the rate is closer to 30 per cent. Of the approximately 1 million cases of tetanus that are reported annually worldwide, an estimated 300,000 to 500,000 people die as a result, the main reason being that they have not been vaccinated.

  A HIGHLY CONTAGIOUS DISEASE

  When deciding which formidable diseases to challenge with the new and growing scientific knowledge that had been acquired in the late 1800s in Louis Pasteur’s and Robert Koch’s laboratories, tetanus certainly presented as a likely candidate. Tetanus had survived unchallenged since ancient times. The Greek physician Hippocrates had written about tetanus in the fifth century BC and there are clinical descriptions of the disease in other documents from that time. In a post Germ Theory of Disease world tetanus was at last in the firing line.

  Shibasaburo Kitasato’s achievements were already significant when Emil Adolf von Behring, who began his career as a doctor in the army, was assigned to the Berlin Institute by the military authorities in 1888 as an assistant to Robert Koch. Born on 15 March 1854 in Hansdorf, West Prussia, which is now in Poland, Emil was one of thirteen children in the Behring family and the first child of nine born to August Behring, the village school teacher, and his second wife, Augustine Zech. Even as a child it was obvious that Emil was intellectually gifted, so much so that the village minister took an interest in Emil’s education and arranged for him to attend the high school in the village of Hohenstein.[7] Influenced by his patron, Emil then began to study theology.

  With his quick mind, Emil found his interests broadening and his focus moved from religion to medicine. Fortunately he was able to begin medical studies at the University of Berlin due to the assistance of a family friend who was a military doctor. When it soon became obvious that the salary of Emil’s school teacher father was inadequate to keep Emil at university, Emil entered the Academy for Military Doctors at the Royal Medical-Surgical Friedrich-Wilhelm Institute in Berlin in 1874 to complete his studies, even though it meant serving for several years in the military after qualifying as a doctor. Behring was awarded his medical degree in 1878 and was entitled to practise medicine after passing the mandatory state examination in 1880.

  It was during the early years of Behring’s career as a military doctor that he first became interested in infection and how substances in the blood fight disease. While working at the chemical department of the Experimental Station in Posen in Poland he gained valuable practical experience as a doctor and in his spare time delved into the study of septic diseases. During the years 1881 to 1883 the young doctor carried out important investigations on the action of the chemical iodoform (a crystalline solid of the organic halogen compounds, first prepared in 1822 and used as an antiseptic in medications). He determined that it did not kill microbes as a vaccine does, but had the capacity to neutralise the poisons given off by them and was thus antitoxic. This early research was crucial to his later studies of tetanus and diphtheria toxins. Behring began publishing his findings in 1882.

  With the advances in medical science the German government began to realise the benefits that could be gained for military health if epidemics could be prevented and combated. Because of Behring’s expertise and his interest in disease he was promoted to the rank of captain and assigned to the medical corps at the Pharmacological Institute at the University of Bonn where he was tutored in experimental methods by the respected pharmacologist Karl Binz. Together they worked on iodoform, which was considered as a highly effective topical treatment for skin ulcers.

  In 1888 Behring received orders to transfer to the Berlin Institute of Hygiene, considered at the time to be at the cutting edge of research. Thrilled with this appointment Behring began his close association not only with Robert Koch but also with Shibasaburo Kitasato and Paul Ehrlich, who had joined the institute in 1890. Many of the young and eager ‘microbe hunters’ later followed Robert Koch when he moved to the Institute for Infectious Diseases in 1891. Behring’s research was inextricably tied to the epoch-making work of these scientists and others—Louis Pasteur, Friedrich Loeffler, Emile Roux, Alexandre Yersin and Elie Metchnikov. Collectively they laid the foundations for the study of bacterial diseases and the science of immunology.

  When Emil von Behring began his work at the Institute of Hygiene other scientists were already conducting research into diphtheria. It had become a serious concern in many countries and the fact that it was a child killer added an emotional urgency to the desire to find ways to fight the disease. Today, most of us in the developed world would never have experienced the disease or even know someone who has had it. But diphtheria was, in the not too distant past, one of the most dreaded diseases and there were frequent large-scale outbreaks in many parts of the world. The diphtheria epidemic that hit the New England colonies in North America between 1735 and 1740 was said to have killed, in some of the towns, as many as 80 per cent of the children under ten years of age.[8] Often whole families died of the disease in the space of a few weeks. No one was safe from the ‘strangling angel’, whether rich or poor.

  By the nineteenth century, as many as 1 in 10 people were afflicted by diphtheria, many of whom died horribly from suffocation, paralysis and heart failure. Ten years before diphtheria research began in earnest in Paris and Berlin, the disease struck the British royal family. Queen Victoria’s daughter, Princess Alice, who was married to the German Prince Louis of Hesse, contracted diphtheria from her children while she was caring for them during their illness. One daughter, Princess Marie, died in November 1878 and Princess Alice herself died a month later.[9]

  The French physician Pierre Bretonneau had given the disease its name in 1826. It is derived from the Greek word for ‘leather’, which alludes to the leathery, sheath-like membrane that grows on the tonsils, throat and in the nose of the afflicted, often blocking the airway and causing them to choke to death. In 1883 Edwin Klebs, a professor of pathology at Zürich University between 1872 and 1892, had discovered and described the diphtheria bacillus, Corynebacterium diphtheriae.The following year, 1884, Friedrich Loeffler, who applied Koch’s postulates in his research, had successfully cultivated the bacillus and proved that it caused diphtheria by injecting it into animals.[10] This was an important milestone in finding a way to prevent the highly contagious disease which was spread so easily through direct physical contact or breathing the secretions of those already infected with Corynebacterium diphtheriae, which also became known as the Klebs-Loeffler bacillus.

  Diphtheria has an incubation period of two to five days. The early symptoms are a sore throat, low-grade fever and the growth of a membrane that adheres to the tonsils, pharynx and, in some cases, the nose. Pharyngeal diphtheria, which takes its name from the pharynx, is the most common form. Laryngeal diphtheria, which involves the voice-box, or larynx, is the form most likely to produce serious complications. In children who become infected symptoms can include nausea, vomiting, chills and a high fever, although some do not show symptoms until the infection has progressed significantly. In 10 per cent of cases victims experience neck swelling, sometimes referred to as ‘bull neck’, which indicates a high level of exotoxin in the bloodstream and is associated with a higher risk of death due to obstruction of the airways.[11]

  In addition to these symptoms, a person who has contracted diphtheria may become pale and listless and develop a fast heart rate. As with tetanus the symptoms are caused by the toxin that the bacterium releases. Some people also develop low blood pressure. Longer-term effects of the diphtheria toxin include cardiomyopathy, a heart muscle disease that impairs the heart’s ability to pump blood, and damage to the sensory nerves in the peripheral nervous system, the network that transmits information from the brain and spinal cord
to every other part of the body.

  ***

  One of the first early effective treatments for diphtheria was developed in the 1880s by an American physician, Joseph O’Dwyer. He inserted specially designed tubes into the throats of victims to prevent them from suffocating from the membrane sheath that obstructed the airways. But this development did nothing to prevent or cure the disease. However, the collaborative research conducted by Emile Roux and Alexandre Yersin at the Pasteur Institute was a significant stepping stone. Building on Friedrich Loeffler’s discovery, Roux, who had assisted Pasteur in his research on the anthrax and rabies viruses, made the first analysis of the chemical properties of the bacillus’s toxin.

  Over a three-year period Roux and Yersin had shown that filtrates of diphtheria cultures which contained no bacilli contained a substance which they called a ‘toxin’. They found that when it was injected into different animals—guinea pigs, rabbits, dogs, cats and horses—all developed diphtheria symptoms. The symptoms were caused by the toxin released by the bacteria, which remained in the filtrate even after the bacteria had been removed.[12] This finding was critical to Emil von Behring’s development of an antiserum to the toxin, which he called an ‘antitoxin’.

  Roux and Yersin published their findings between 1888 and 1891. In their first publication they confirmed Loeffler’s methods of cultivating the bacteria. They presented their conclusion that the diphtheria bacillus was capable of producing a poison, or diphtheria toxin, and had proved this by passing cultures of the diphtheria bacillus in a broth through porcelain Chamberland filters. The bacteria were trapped but the sterile filtrate caused the disease when it was injected into experimental animals. In their second paper, published in 1890, Roux and Yersin described in detail their procedure for producing the toxin and reported the results of their in-depth and complex investigations into its pathogenic effect on various experimental animals.[13] A technique for the laboratory diagnosis of diphtheria was outlined in their third paper, which came out in 1891.

  Today a diphtheria diagnosis is confirmed by taking a swab of material from the infected area and placing it on a microscope slide where it is stained using a procedure called Gram’s stain. The diphtheria bacillus is called gram-positive because it holds the dye after the slide is rinsed with alcohol. Under the microscope, diphtheria bacilli look like beaded rod-shaped cells, grouped in patterns that resemble Chinese characters. Another laboratory test involves growing the diphtheria bacillus on what is called Loeffler’s medium, after Friedrich Loeffler.[14] He had developed a new medium in which to isolate and cultivate the diphtheria bacillus as Koch’s gelatin method did not work with the diphtheria pathogen. So many of the great scientists have given their names to procedures and protocols and often the connection between the name and what was achieved has been lost over the years.

  A MONUMENTAL BREAKTHROUGH FOR IMMUNISATION

  In 1889 Emil von Behring realised that Yersin and Loeffler had given him a starting point from which he could work to develop an immunising serum for diphtheria. It was also at this point that the collaboration between Behring and Kitasato began. Informed by the observations Behring had made some years earlier on the action of iodoform, the two scientists, experimenting mainly with diphtheria and tetanus bacilli, set out to find whether they could disinfect the living organisms with various disinfectants.[15] What they did find was that when animals were injected with graduated doses of attenuated forms of toxins, their blood produced antitoxins which would neutralise the invading bacilli. This meant that animals injected with the bacilli that cause tetanus and diphtheria produced substances in their blood that neutralised the toxins produced by the bacteria.

  Behring and Kitasato repeated their experiments with rats, guinea pigs and rabbits, injecting them with attenuated forms of diphtheria and tetanus bacilli. The next phase was to inject blood serums produced by these animals into non-immunised animals that had previously been infected with the fully virulent bacteria. The antitoxins miraculously cured the ill animals. The third breakthrough was that healthy animals became immune to the diseases when they were injected with the blood serum and they remained resistant for long periods of time. Antitoxin serum extracted from their blood could then be used to treat other animals.[16] This finding was to prove monumental in explaining the workings of the immune system and in the development of future vaccines.

  In 1890, Kitasato and Behring jointly published their classic paper, ‘The Mechanism of Immunity in Animals to Diphtheria and Tetanus’, reporting on their discovery that for the first time the passive immunisation method was used to fight infectious diseases because the presence of tetanus and diphtheria toxins in blood causes the blood to produce antitoxins that neutralise the poisonous substances.[17] Emil von Behring called this new procedure ‘Blood Serum Therapy’. What made it vastly different to vaccination was that in Blood Serum Therapy it was possible to provide an animal with passive immunity by injecting it with the blood serum of another animal infected with the disease, not with a vaccine made from the infective organism. The news of a ‘real cure’ created a sensation. Behring and Kitasato continued to repeat their experiments so that there could be no doubt about their findings. Other scientists did likewise which resulted in a flurry of publications confirming the original results.

  Hard on the heels of his joint publication with Kitasato in 1890, Behring—now as a sole author—published an authoritative paper dealing with immunity against diphtheria and outlining five ways in which this could be achieved. He had conceived of the idea that curing both tetanus and diphtheria in humans might now be possible by producing an antitoxin against them. To achieve this, Behring collaborated with his university friend ErichWernicke on the first therapeutic serum for diphtheria, and with Shibasaburo Kitasato he developed an effective therapeutic serum against tetanus.[18] The tetanus antitoxin was made by first injecting the tetanus bacteria into an experimental animal, such as a rabbit or guinea pig. The blood was then removed from the infected animal. Next, that blood was injected into a second animal, such as a horse. Finally, the blood was removed from the second animal, and from this blood the vaccine to be used on humans was made.

  In 1891 the tetanus serum was introduced but not entirely in the way Behring had hoped. The Institute of Hygiene had the support of the Agricultural Ministry to develop tetanus serum but the ministry’s main concern was with protecting valuable agricultural animals.[19] Behring’s primary motive had been to help humans and it was not based on economics. Elation gave way to disillusionment when it became obvious that he had no support for large-scale clinical testing of the serum on humans. A program for protecting animals went ahead and the considerable amounts of blood serum required were obtained through immunising horses.

  A wonderful opportunity to help humankind had been squandered and some twenty years later when World War I broke out in 1914, because there had been insufficient ‘proof of the pudding’, the military were reluctant to use the life-saving tetanus serum. During the first months of the war the Germans suffered massive losses and thousands of those lives, lost to tetanus, could have been saved. There were some hit-and-miss attempts to use the tetanus antitoxin serum in a number of military hospitals which failed dismally. There was very little of the precious blood serum available and what little there was, was often mishandled because many practitioners had not been adequately trained in its use.

  At the end of the first year of the war Behring could no longer stand by and accept the unnecessary deaths. He waged his own campaign to have the authorities support the use of the serum. By this time he was in a position to exercise some influence and by April 1915 the earlier setbacks of distribution and control were overcome as he was personally involved in the production of the serum at his own laboratory.[20] In army hospitals the serum was used for both treatment and prophylaxis and the numbers of soldiers succumbing to tetanus fell dramatically. Emil von Behring was hailed as the ‘Saviour of the German Soldiers’ and his contribution was
recognised with the award of the Prussian Iron Cross medal. This was the proof that tetanus could become a preventable and a curable disease.

  ***

  The development of the diphtheria serum took a different course. Emil von Behring developed his therapeutic serum for diphtheria in 1891. The antitoxin did not kill the bacteria but neutralised the toxic poisons that the bacteria released into the body. More than 50,000 children in Germany were dying every year from diphtheria and 1891 was a particularly bad year as the vicious disease with the mellifluous name was taking a huge toll on the young.[21] There was no time to waste and the serum was used for the first time to treat a seriously ill child. She made a full recovery. In 1892 the Hoechst chemical and pharmaceutical company at Frankfurt am Main became interested in the therapeutic potential of the diphtheria antitoxin (and no doubt in the financial potential as well) and began working with Behring to develop the serum to make it viable.

  By 1893 Behring had successfully treated a group of human diphtheria patients with antitoxin but there were constant setbacks because the toxin did not yield consistent results. Enter Paul Ehrlich. He who had improved Koch’s method of staining the tubercle bacilli in 1882 was chiefly responsible for standardising the diphtheria antitoxin, thus making its widespread therapeutic use possible. Ehrlich had determined that the toxin–antitoxin reaction, which is a chemical reaction, was accelerated by heat and retarded by cold and that the content of antitoxin in antitoxic serums varied greatly for a range of reasons. Therefore it was necessary to establish a standard by which the antitoxin content could be measured exactly. The method that Ehrlich devised for determining the effectiveness of serums, not just diphtheria serum, was soon adopted all over the world.