This lesson will increase your knowledge of concepts covered in the following TEKS for biology: 3.f – Research and describe the history of biology and contribution of scientists. 4.c – Compare the structures and functions of viruses to cells and describe the role of viruses in causing diseases and conditions such as acquired immune deficiency syndrome, common colds, smallpox, influenza, and warts 4.d – Identify and describe the role of bacteria in causing disease 8.c – Identify characteristics of kingdoms including monerans, protists, fungi, plants, and animals 12.b – Interpret interactions among organisms exhibiting predation, parasitism, commensalisms, and mutualism 12.c – Compare variations, tolerances, and adaptations of plants and animals in different biomes 12.d – Identify and illustrate that long-term survival of species is dependent on a resource based that may be limited

Today’s Lesson Parasites and Disease

Overview of Lesson Fleas and plague Mosquitoes, malaria and West Nile virus Ticks and Lyme disease

The Plague killed 25% of people in medieval Europe Woodcut memorializing the Great Plague of London, which killed 70,000 0f 460,000 residents From: Discover, November 2001

17 th century doctors did not understand the cause of the plague Doctors wore protective clothing and inspected patients with pointers. Spice-filled pomanders were used to fend off the black death. From: Discover, November 2001

Flea: feeds on blood of mammals and birds, spreading the bacteria that causes plague

Based on Raven et al., Biology, McGraw Hill Human Populations Growth

Overview of Lesson Fleas and plague Mosquitoes, malaria and West Nile virus Ticks and Lyme disease

Mosquito Eggs Stages of Larvae Emerging From Pupal Stage Pupa Adult Based on: National Geographic, September 1979 Mosquito Life Cycle

Based on: Scientific American, June 1978 Adult Female Mosquito Feeds on blood for protein to make eggs

Distribution of Malaria Based on: U.S. News & World Report, January 1997

Plasmodium - protozoan that causes malaria and destroys red blood cells

Life Cycle of Malarial Parasite

Historic Efforts to Defeat Malaria Drained wetlands to reduce habitat for mosquito reproduction –But we lost important wetlands Control of mosquitoes using pesticides –But mosquitoes developed resistance Drugs (chloroquine) to protect humans against infection by Plasmodium –But Plasmodium developed resistance

Risk of Malaria: 1946, 1966 & 1994

New Efforts to Defeat Malaria From: Science, 4 Oct. 2002

West Nile virus appeared in U.S. in 1999 West Nile virus isWest Nile virus is spread by mosquitoes spread by mosquitoes West Nile can cause flu-like symptoms to fatal brain swellingWest Nile can cause flu-like symptoms to fatal brain swelling About 20% of infected humans get sickAbout 20% of infected humans get sick Virus has been identified in over 200 bird speciesVirus has been identified in over 200 bird species As of 2008 West Nile had been identified in all continental states. Has not been found in Alaska or Hawaii Spread of West Nile Virus

Overview of Lesson Fleas and plague Mosquitoes, malaria and West Nile virus Ticks and Lyme disease

Ticks feed on blood to get protein to make eggs. They anchor their mouthparts below the skin.

After feeding Before feeding

Life Cycle of Deer Tick and Lyme Disease Based on: Harvard Health Letter, 1991

Lyme Disease

Based on: Time, July 28, 1997 Number of Lyme Disease Cases in 1996

Corkscrew-shaped bacteria causing Lyme disease

The nymph stage of the deer tick transmits Lyme disease It injects an anesthetic into the skin to mask the pain of bite

Effects of Lyme Disease Flu-like symptomsFlu-like symptoms Bull’s eye rash at site of bite Arthritis-like symptoms in joints, facial palsy, irregular heartbeatArthritis-like symptoms in joints, facial palsy, irregular heartbeat Bacteria may attack nervous system resulting in behavioral and memory changesBacteria may attack nervous system resulting in behavioral and memory changes Death is rareDeath is rare

Treatment of Lyme Disease Antibiotics for a couple of weeks can treat the illnessAntibiotics for a couple of weeks can treat the illness

Rash of Lyme Disease From: Scientific American, July 1987

Clear brush around your home and keep grassy areas mowed Stay in middle of hiking trails Wear light-colored clothing to be able to spot dark- colored ticks more easily Spray clothes with repellents, particularly around cuffs and waistline Pull your socks over your pants legs and tuck your shirt into your pants Inspect children at least once a day for ticks, every 3-4 hours in heavily infested area Pay special attention to the groin area, naval, armpits, head and behind knees How to Stay Lyme-Free

Based on : Harvard Family Health Letter, April, 2000 How to Remove a Tick

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