L.O: To understand the contributions of Semmelweis in controlling infection Friday, June 03, 2016

How does this advert help to control infection?

 One easy way to defend the body against illness is by keeping it clean and hygienic as microbes can spread very quickly in unhygienic conditions  The spreading of microbes is known as transmission  As soon as a virus or bacterium enters the body, we are termed infected (not the same as being ill – illness results from the effects these microbes have on our body  Bacteria and viruses have the ability to produce poisons known as toxins

A scientist called Semmelweis collected this data. What do you think could have caused the differences between the first division and second division wards? What would you investigate as a scientist?

Semmelweis’s Discovery Explain in your own words simply how Semmelweis helped to control infection In the late 1840's, Dr. Ignaz Semmelweis was an assistant in the maternity wards of a Vienna hospital. There he observed that the mortality rate in a delivery room staffed by medical students was up to three times higher than in a second delivery room staffed by midwives. In fact, women were terrified of the room staffed by the medical students. Semmelweis observed that the students were coming straight from their lessons in the autopsy room to the delivery room. He postulated that the students might be carrying the infection from their dissections to birthing mothers. He ordered doctors and medical students to wash their hands with a chlorinated solution before examining women in labor. The mortality rate in his maternity wards eventually dropped to less than one percent.

Hospitals are trying to be more hygienic YearAmount of hand wash solution used (litres per 1000 patient days) MRSA infections per 100 patients

 In the late 1840’s Dr. Ignaz Semmelweis noticed that the death rate in a delivery room was high  He thought that the doctors were carrying infections between patients and ordered doctors wash their hands with a chlorinated solution before examining women in labour  The mortality rate in his maternity wards eventually dropped from twelve percent to less than one percent

The work of Louis Pasteur Pasteur discovered that by heating the grapes to a high temperature before fermentation, the wine did not go sour, as the bacteria had been killed. This technique is called pasteurization. Whilst investigating why wine went sour Pasteur discovered that yeast caused fermentation, and bacteria caused the wine to go off. People found these results surprising as they didn’t realise that bacteria could cause chemical changes. Pasteur suggested that micro-organisms can cause disease, forming the basis of the germ theory of disease.

Pasteurization There are several different types of pasteurization: Pasteurization is now widely used in food and drink production to prevent unwanted (and potentially harmful) micro-organisms from growing. conventional low temperature holding (LTH) – liquid is heated to 60 °C for 40 minutes Pasteurization using a higher temperature will kill off a wider range of micro- organisms. In order to prevent contamination it’s also important that the equipment used at each stage of food production is sterilized. ultra-high temperature (UHT) – 140 °C for 2 seconds.

Your task: To set up agar plates to test whether different handwashes affect the growth of bacteria. Microbial Practical

 Diseases can be transmitted via: - 1.Droplet transmission (sneezes & coughs) 2.Water transmission (polluted water) 3.Vector transmission (animals) 4.Contact transmission (person to person)

 If an infected person sneezes or coughs, millions of microbes are released into the air  These microbes could then infect somebody else…

 Microbes can feed off the pollution within water  If water is not cleaned, the microbes can reproduce and enter the body when the water is drunk

 A vector is an animal that carries the microbe from one place to another  Vectors can range from houseflies to pets

 Many microbes can be exchanged from one person to another within bodily fluids e.g. blood and semen – this is how many microbes responsible for sexually transmitted diseases are spread from person to person  The less hygienic people are, the greater the chance of infection  Microbes will also reproduce rapidly in unhygienic conditions – this is the main reason why public places such as restaurants have to abide by strict hygiene regulations