Posted in Psychology & Medicine

Typhoid Mary

New York City, 1901 – an upper-class family presented with fevers and diarrhoea, diagnosed with the infection typhoid fever. This was unusual as typhoid fever was classically associated with poor hygiene, overcrowding and lower socioeconomic status households. It was atypical to see typhoid fever in upper-class households. Within a year, a lawyer and his household fell ill to the same disease – 7 out of 8 people contracted typhoid. Another case emerged 5 years later in Long Island, New York – an area where typhoid fever was very uncommon. This time, 10 out of 11 family members were hospitalised with typhoid. Countless families fell victim to typhoid fever within this year and people started becoming curious as to the cause of this epidemic.

In 1906, typhoid researcher George Soper began investigating the epidemic and found a common link between all of the families who became sick. They had all at some point employed a cook by the name of Mary Mallon. Soper noticed that Mallon had worked for each of these families roughly three weeks before each of them fell victim to the illness, upon which she would leave the job for another family. Soper approached Mallon to obtain urine and stool samples to prove this, but Mallon adamantly refused and denied any responsibility in her possible role in spreading typhoid as she “was not sick”.

Eventually, the New York City Health Department appointed Dr Sara Josephine Baker to handle the situation. Mallon still refused to comply with the investigation and had to be taken into custody by the police. She was forced to be tested while in prison, which proved that she was an asymptomatic carrier of typhoid fever. Doctors discovered that she had a significant growth of typhoid bacteria in her gallbladder. It was determined that Mallon has infected the families through preparing and serving food (she was famous for her ice cream) with poor hand hygiene.

Due to her non-compliance to the order of restricting her from being a cook, Mallon was quarantined for the rest of her life until she died from a stroke in 1938. Mallon – or as the media called her, “Typhoid Mary” – was the source of at least 51 confirmed typhoid fever cases, three of which were fatal. Some estimates say she could have been responsible for as many as 50 deaths as she had worked under many aliases. All because she did not wash her hands properly.

Posted in Psychology & Medicine


In 1976, an outbreak of a viral illness was identified in Sudan. Patients would present with symptoms of high fever, headache, vomiting, diarrhoea and a spotted rash, but would rapidly deteriorate in health. Within days, patients showed signs of decreased blood clotting, such as bleeding from intravenous line sites, having blood in their vomit and stool, or bleeding from essentially any bodily orifice. If untreated, patients would die within two weeks of shock (very low blood pressure), kidney failure or bleeding into the brain. The outbreak killed 151 people before it disappeared.

Later in the year, a headmaster at a school in Zaire developed a similar disease after travelling to the Ebola River. He died two weeks later. Soon after, people he came in contact with after his trip died of similar symptoms. The World Health Organisation investigated this epidemic and realised that the disease was caused by a new type of virus, which was named ebola virus. Due to its symptoms, the disease caused by the virus is named ebola haemorrhagic fever.

Since the discovery of the disease, occasional ebola outbreaks were seen in various parts of Africa, mainly around Congo and Uganda. Each time, the disease would rapidly claim the lives of hundreds of people and then vanish. This is because ebola virus was so effective in killing people (with a death rate of 90% in one outbreak), that it would kill the infected person before they spread the disease further.

The virus can be spread through any bodily fluid, including blood, tears, semen and sweat. Because of this, once an infected patient is brought into hospital, the disease can spread rapidly throughout the building and infect many patients and hospital staff if proper precautions are not taken. Fortunately, the virus is not known to spread when the patient is in the incubation period (when they are infected but have not shown symptoms yet).

The origin of the virus has been traced back to fruit bats (like many other serious viruses). Fruit bats have extremely powerful immune systems to protect their cells from the harmful metabolites produced by flying, allowing bats to harbour deadly viruses without succumbing to them. These viruses have also evolved to withstand the high temperatures produced by flying (which involves significant muscle work), meaning they can easily survive the high fevers they cause in humans. The transmission from bats to human in modern times is likely attributed to deforestation and humans encroaching into the bats’ native territory.

The current epidemic that originated from West Africa is the biggest ebola outbreak so far, having infected over 9000 people and claiming the lives of over 4500 people (October 14, 2014). However, this is likely a grossly underestimated number. The epidemic is focussed mainly in Guinea, Sierra Leone, Liberia and surrounding countries, but has infected foreign workers and volunteers who have been repatriated to be treated in their home country.

Despite a robust effort from the WHO to try and curb this epidemic, the infection rate continues to climb due to various factors, such as traditional funeral rites involving touching the deceased person’s body, which is still infective after death. There are currently no effective vaccines or treatments and the only thing that can be done is supportive treatment in an intensive care unit where the patient can be adequately hydrated and monitored. Like with most communicable diseases, the most effective treatment is preventing the disease from spreading through education, rigorous infection control protocols and improved healthcare systems in the affected countries.

Posted in Psychology & Medicine

Laughter Epidemic

It is said that laughter is infectious. In 1962, an extreme case of “laughter infection” happened in village in Tanzania. The phenomenon originated in a boarding school for girls. On January 30, three girls spontaneously burst out in laughter and could not stop themselves from laughing. Soon after, the whole class was suffering from fits of uncontrollable laughter. The “infection” then spread throughout the school, claiming 95 of the 159 students over a stretch of two months. This strange symptom of uncontrollable laughter lasted anywhere from a few hours to 16 days. Interestingly, teachers were not affected and only girls between the ages of 12 to 18 were affected. By March 18, the school was forced to close down due to students not being able to focus during class.

The laughter epidemic was not localised to the school. After the school shut down and the girls returned home, fellow villagers were afflicted by the laughing disease, resulting in 217 villagers being “infected” by May (mostly children and teenagers). By June, the laughing epidemic spread to another nearby school, affecting 48 girls. The epidemic then went on to claim two more schools, forcing them to close down. By the time the epidemic died down (6 to 18 months after “patient zero”), it had affected over a 1000 people and shut down 14 schools.

So what was this strange disease? Was it some new viral infection causing neurological symptoms? Was it a toxin in the water supply? The answer was even simpler: mass psychogenic illness, also known as mass hysteria. Mass hysteria is a psychological phenomenon that occurs in groups placed in high-tension situations, such as within an airplane. This setting is perfect for triggering a mass delusion, causing the person to believe they are suffering from a physical disease. The trigger is usually another “patient” and the hysteria spreads like wildfire, usually by people seeing affected victims. Although the above case makes mass hysteria look like a harmless, amusing phenomenon, psychosomatism (when the mind tricks the body into thinking it is sick) can cause symptoms such rashes, fevers, vomiting and even paralysis. In fact, all of these symptoms were also reported during the Tanganyika laughter epidemic.