1. ‘Filth Diseases’

2. The term ‘Filth Diseases’
We are used to thinking of infectious disease causing great human suffering, but there are some diseases that actually seem to thrive in conditions of filth and misery
The term ‘filth diseases’ has its origins in the 19th century when some physicians believed that filth itself was the cause of diseases
Although the discovery of microbes in the late 19th century displaced the ‘filth theory’ of diseases, it is still a useful term to identify some infectious diseases that lead to epidemics and pandemic
Seen in historical perspective, diseases like typhus and cholera thrive in conditions where human suffering is already at high point

3. Typhus (Rickettsia prowazekii)
Rickettsia prowazekii is a bacterium that causes the epidemic typhus
Its main vector is human body lice; they become infected when they feed off an infected person; they then pass on the infection to other humans through their excrement which makes its way into the human body through their bite mark or some other opening in the skin
In most of the world humans are the reservoir of the bacterium

4. Sufferers can be asymptomatic but still be able to infect lice
The pathogen probably originated in early civilizations, making the jump from animals to humans
Although it has been around for a long time, it is not really recoded much before the 15th century, likely because its symptoms (a high fever accompanied by a rash) can be confused with other diseases
Untreated, it can have a morbidity rate of up to 60 per cent of adult victims
Sufferers can be asymptomatic but still be able to infect lice
Body louse with ingested blood meal

5. The name typus
The term typhus was coined in the sixteenth century and was taken from the Greek word τύφος – meaning smoky or hazy – which reflects one of the main symptoms of the infection as it attacks the brain and causes delirium
The name reflects the humanist interest of sixteenth century physicians who read Greek
This also reflects the way in which diseases are socially constructed – until they have a name and some sort of epidemiology, they do not really get noticed, even though their existence on a biological level is ancient

6. First recorded epidemic in 1489
The first recorded epidemic of typhus occurred as a Spanish Army of 25,000 was laying siege to the Muslim stronghold of Granada
Sources cite the figure of 17,000 soldiers succumbing to the disease
Historians argue that the pathogen reached Spain with Spanish soldiers returning from the Crusades
From Spain the pathogen was transmitted to Italy with Spanish mercenary soldiers

7. Siege of Naples 1528
In 1528 a French army of about 28,000 was facing a much smaller Imperial army for control of Italy
Despite the greater strength of the French army, and outbreak of typhus devastated French forces, causing them to retreat
This was a significant victory from Charles V of Spain who was able to secure the title of Holy Roman Empire

8. The Thirty Years War (1618-1648)
The Thirty Years’ War originated as a conflict between Catholic and Protestant states in Germany, but eventually grew through alliances to encompass all the great powers of Europe
The campaigns of this war are noted for their brutality, intensity, and for the suffering that warfare wrought on the civilian population
The greatest killer in these campaigns, especially before 1630, was typhus, which took millions of victims, soldiers and civilians alike
Many more people died as a result of disease than the actual battles, which raised the intensity of the stuggle

9. Napoleon’s invasion of Russia 1812
Although medical knowledge about typhus had increased by the 19th century, it had a devastating effect on Napoleon’s 600,000 man invasion force of Russia
Despite being warned by his medical advisors that his soldiers could not withstand the Russian winter, Napoleon went ahead
It is estimated that nearly half of his invading army was killed by typhus; starving through the Russian winter his soldiers descended upon the peasants in the countryside … likely this is where they encountered typhus which spread so quickly throughout his army

10. Typhus and warfare
As these examples show, warfare created the perfect breeding ground for typhus
Because soldiers interact with the local civilians, and often seize their dwellings and goods, it increases their contact with infected lice
The cramped conditions, lack of food, sanitation, and generally dirty conditions make it a good breeding ground for lice
Because body lice were so common in the pre-modern period, people would have seen them as a nuisance, but would not have identified lice as a disease vector and would have seen them as relatively harmless

11. Cholera
Like typhoid fever, cholera also comes from infected water supply contaminated by feces containing the bacterium
It originated in the Indian subcontinent centuries ago, and only started to spread widely into the rest of the world as a result of trade and empire starting in the seventeenth century
Since 1800 there have been seven cholera pandemics across the world, and has been responsible for millions of deaths across the globe

12. Typhoid fever
The infectious disease typhus must not be confused with the separate infection typhoid fever
Although they have similar names, they have little in common, except for the fact that they both cause abdominal pain and fever
The pathogen causing it, Salmonella typhi, comes from contaminated food or water, and also can come from unwashed hands, thus a completely different vector
Another similarity is that a person can carry the the pathogen and pass it on

13. The case of “Typhoid Mary”
The case of so-called “Typhoid Mary” is an instructive one for our study of disease because it shows the intersection of infectious disease, medical knowledge, public health precautions and the ramifications of enforcing public health measures
As you watch the documentary, think about how the issues raised by this case might have worked out in different parts of the world, with different infectious diseases, at different times
Also, the issues raised in the documentary will also set up the topic for next week’s lecture on the advances that have been made by modern science against infectious diseases