Scientific Method

Be a Scientist

Scientific Method

• What do you know about disease?• How do people get sick?• Do other animals get sick too?• How o scientists study diseases?

Scientific Method

1. Make Observation2. Ask Question3. Form a Hypothesis4. Test Your Hypothesis5. Results Supported6. Results Do Not Support7. Conclusion, or Reform Question

Scientific Method

Scientific MethodAdult Mosquito

Mosquito eggs in Flood water.

Mosquito larva in development

Scientific Method

Adult mosquito emerges from the water.

Scientific Method

Swamps and standing water.

Flood waters.

Where mosquitoes live and breed!

Scientific MethodMosquitoes will live anywhere where there is standing water!

Tree holes that hold water. Old tires that collect rain water.

Anything that can collect water! Control mosquitoes by controlling trash!

Scientific MethodMosquitoes feed by absorbing blood from a host! Yuck!

Scientific Method

Mosquitoes can carry and transfer Malaria, Yellow Fever and Dengue Fever!

Mosquitoes can transfer these diseases to other creatures while feeding on a host! (YUCK!)

Scientific MethodMosquitoes can spread the virus by infecting a host, such as a chipmunk.

As other Mosquitoes feed off of the chipmunk, they become infected and continue to spread the disease to humans!

Scientific Method

• How do you think scientists every made the connection between Mosquitoes and these different diseases?

Malaria in the blood! (Notice the cells that are not round!)

Scientific Method

• Discovery of the Malaria Parasite (1880)• Charles Louis Alphonse Laveran, a French

army surgeon stationed in Constantine, Algeria, was the first to notice parasites in the blood of a patient suffering from malaria. This occurred on the 6th of November 1880. For his discovery, Laveran was awarded the Nobel Prize in 1907.

Scientific Method• Discovery That Mosquitoes Transmit Malaria Parasites

(1897-1898)• On August 20th, 1897, Ronald Ross, a British officer in the

Indian Medical Service, was the first to demonstrate that malaria parasites could be transmitted from infected patients to mosquitoes. In further work with bird malaria, Ross showed that mosquitoes could transmit malaria parasites from bird to bird. This necessitated a cycle (the time interval during which the parasite developed in the mosquito). Thus, the problem of malaria transmission was solved. For his discovery, Ross was awarded the Nobel Prize in 1902.

Scientific Method• On 20 August 1897, in Secunderabad, Ross made his landmark

discovery. While dissecting the stomach tissue of a mosquito fed four days previously on a malarious patient, he found the malaria parasite and went on to prove the role of Anopheles mosquitoes in the transmission of malaria parasites in humans.

• He continued his research into malaria in India, using a more convenient experimental model, malaria in birds. By July 1898, he had demonstrated that mosquitoes could serve as intermediate hosts for bird malaria. After feeding mosquitoes on infected birds, he found that the malaria parasites could develop in the mosquitoes and migrate to the insects' salivary glands, allowing the mosquitoes to infect other birds during subsequent blood meals.