Bellwork: 10/18/2012 Today – Complete Notes over Helminthes, Complete lab from Tuesday. Friday – Weekly chemistry, begin review, begin review quiz Monday – Complete review, complete review quiz Tuesday – Unit #3 Exam

Microbial Contaminant Lab: Station 6 **Groups of 3 or fewer 1. Atrazine is an endocrine disruptor. What does that mean? What type of product is atrazine found in? What threat does this pose to human & non-human life? 2. What is bioaccumulation? What types of chemicals tend to bioaccumulate? Describe an environmental situation where this occurred. 3. What is thermal pollution? How/why does this occur? Is this damaging to an environment? If so, how? In what way have we prevented environmental damage while maintaining factory/power plant output? 4. Write out the nitrogen cycle. Label the aerobic & anaerobic reactions. Label the reaction that is responsible for fixing nitrogen. What does it mean to “fix” nitrogen? If this reaction ceased to occur, what would the consequence be for higher- level organisms?

HELMINTHES Water Born Flat worms and Round worms

HELMINTHOLOGY Phylum Platyhelminthes = Flat worms Class Trematoda = Flukes Class Cestoda = Tape worms Phylum Ashelminthes = Round worms Class Nematoda Genus Ascaris Genus Trichinella Genus Necator, Ancylostoma Genus Enterobius Genus Dranunculus Genus Wucereria

HELMINTHOLOGY Phylum Platyhelminthes = Flat worms Class Trematoda = Flukes Some flukes are single sex, some are hermaphroditic possessing both ovaries and testes.

Hermaphroditic Flukes

FIGURE Schistosoma mansoni egg in a fecal specimen (X1000, D’Antoni’s iodine stain). Schistosoma mansoni eggs are large (114 to 175 µm long by 45 to 70 µm wide) and contain a larva called a miracidium. They are thin-shelled, lack an operculum, and have a distinctive lateral spine (arrow).

FIGURE Schistosoma mansoni egg in a fecal specimen (X1000). The lateral spine may be oriented in such a way as to be difficult to see. In this specimen, the spine (arrow) is above the egg and the egg may be misidentified as S. haematobium.

FLAT WORMS Phylum Platyhelminthes = Flat worms Class Cestoda = Tape worms Scolex contained in egg holdfast structure with hooks and suckers Proglottids major body of tapeworm contains both ovaries and testes = hermaphroditic Eggs can penetrate intestine of host and form hydatid cysts in tissues

FIGURE Taenia solium scolex (X64). The Taenia solium scolex has two rings of hooks and four suckers.

ROUND WORMS Phylum Ashelminthes = Round worms Class Nematoda Genus Ascaris – most common Genus Trichinella Biblical worm Genus Necator, Ancylostoma - hookworms Genus Enterobius – pinworm 2 nd most common Genus Dranunculus - Guinae Genus Wuchereria - Elephantiasis Mosquito borne

Hookworms ► Ancylostoma duodenali: Human phase of this worm begins with a filaform larvae penetrating the skin, enters circulation, carried to the lungs, coughed up and swallowed, develops to adulthood in small intestine. Adult worms lay between 10,000 and 20,000 eggs per day. Daily blood loss 0.2ml/adult/day. Microcytic hypochromic anemia develops.

FIGURE Heads of adult hookworms. (a) Ancylostoma duodenale head (X64) showing the pairs of chitinous teeth (arrow). (b) Necator americanus head (X160) showing the cutting plates (arrow). a b

Biblical worm ► Trichinella spiralis etiological agent of trichinosis. Infectious larva is present in the striated muscle of carnivorous and omnivorous mammals. Swine most common organism to transmit to humans. Encysted larvae live for many years. Polar bears and walruses are accounting for new human infestations in our Alaskan artic regions.

FIGURE Trichinella spiralis larva in skeletal muscle (W.M., X260). The spiral juvenile and its nurse cell are visible in this preparation.

FIGURE Trichinella spiralis larvae in skeletal muscle (sec., X260). Each larva has entered a different skeletal muscle cell and converted it into a nurse cell that sustains it with nourishment.

Ascaris Lumbricoides ► Large worms 25cm – 45cm in length. Most common helminth with over a billion infested a year. Prevalent in areas where sanitation is poor and human waste is used as fertilizer. ► Ingested egg releases a larva that penetrates the duodenal wall and carried to the liver and the heart, enters the pulmonary system, enters the alveoli where they molt and mature. They are coughed up, swallowed and returned to the small intestine. Adults can be passed out into the feces.