1. The Eukaryotic Members of the Microbial World
Algae
Protozoa
Fungi
Molds
Arthropods and Helminths 1

2. Algae Eukaryotic cell structure Microscopic and macroscopic sizes
Cell walls
Part of a group of organisms called phytoplankton (primary producers in the oceans)

3. Algal Toxicity Red tides caused by
G. breve now K. brevis (Karenia brevis ): Brevetoxin kills fish feeding on phytoplankton and causes illness in ho and animals. (Famous Florida red tides).
Gonyaulax: neurotoxins that accumulates in shellfish (immune to it) cause paralytic shellfish poisoning in ho and animals. Death possible.
Phytoplankton:This resource is much more important for the survival of this planet than all the rainforests and prairies put together. The microscopic plants of the sunlit surface waters of the oceans capture more oxygen than all other life forms. These are the organisms most likely to be affected by global warming, climate change and man’s indiscriminate and careless pollution of the oceans.
 Red tides occur throughout the world, drastically affecting Scandinavian and Japanese fisheries, Caribbean and South Pacific reef fishes, and shell fishing along U.S. coasts. Most recently, it has been implicated in the deaths of hundreds of whales, dolphins, and manatees in North American waters. These red tides are caused by several species of marine phytoplankton, microscopic plant like cells that produce potent chemical toxins. The Florida red tide is caused by blooms of a dinoflagellate that produce potent neurotoxins. These toxins cause extensive fish kills, contaminate shellfish and create severe respiratory irritation to humans along the shore.
Humans get ill from consuming contaminated shellfish and from inhaling brevetoxin suspended in sea spray. K. Brevis has been associated with two medical conditions: Neurotoxin Shellfish Poisoning and Respiratory Irritation from aerosolized brevetoxin

4. Protozoa Protozoan habitats Structure of protozoa
Mostly free – living, some parasitic
In marine (zooplankton) , fresh water and terrestrial environments
Structure of protozoa
Microscopic, unicellular, no chlorophyll
No cellulose cell wall (instead silicon, Ca etc.)
Cilia, flagella, pseudopodia  grouped acc. to mode of locomotion

5. Protozoan Reproduction
Sometimes complex life cycles
Protozoa can
be polymorphic
have vegetative (feeding) form = trophozoite or
resting form = cyst
Sexual or asexual reproduction

6. Protozoa and Human Disease
Malaria (Plasmodium species)
African sleeping sickness (Trypanosoma brucei)
Toxoplasmosis (Toxoplasma gondii)
Vaginitis (Trichomonas vaginalis)
A trophozoite of Trichomonas vaginalis from culture.  The four flagella and single nucleus are visible.  Symptomatic infections are characterized by a white discharge from the genital tract and itching.  Diagnosis depends on finding trophozoites in secretions of the genital tract from men or women.  In cases where the numbers of organisms are very low, the trophozoites can be cultured to increase their numbers (see below).
Trichomoniasis can usually be cured with the prescription drug metronidazole given by mouth in a single dose. The symptoms of trichomoniasis in infected men may disappear within a few weeks without treatment. However, an infected man, even a man who has never had symptoms or whose symptoms have stopped, can continue to infect a female partner until he has been treated. Therefore, both partners should be treated at the same time to eliminate the parasite. Persons being treated for trichomoniasis should avoid sex until they and their sex partners complete treatment and have no symptoms. Metronidazole can be used by pregnant women.
Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. The parasite is found throughout the world. More than 60 million people in the United States probably carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness.
You may feel like you have the "flu," swollen lymph glands, or muscle aches and pains that last for a month or more. Rarely, a person with a "normal" immune system may develop eye damage from toxoplasmosis. However, most people who become infected with toxoplasmosis do not know it. Persons with weak immune systems, such as infants, those with HIV/AIDS, those taking certain types of chemotherapy, or persons who have recently received an organ transplant, may develop severe toxoplasmosis. This can cause damage to the brain or the eyes. Most infants who are infected while in the womb have no symptoms at birth but may develop symptoms later in life. Only a small percentage of infected newborns have serious eye or brain damage at birth. Infants born to mothers who became infected with Toxoplasma for the first time DURING or JUST BEFORE pregnancy.

7. Fungi Fungi are omnipresent
Structure of fungi (yeasts, molds and mushrooms)
Only few fungi cause disease in animals (mostly in immunocompromised individuals)
Economic importance
wine, beer, bread, and cheese production
Antimicrobial medicines
Biotechnology
Many plant pathogens

8. Fungal Disease in Humans
Four types of fungal diseases
Allergies
Toxicities
Mycoses
Starvation due to food destruction
Examples of fungal diseases
Candida albicans (candidiasis)
Cryptococcal meningoencephalitis
Histoplasma capsulatum (Histoplasmosis)
Pneumocystis carinii
 Frequently Asked Questions
What is histoplasmosis?
Can anyone get histoplasmosis?
How is someone infected with H. capsulatum?
What are the symptoms of histoplasmosis?
When do symptoms start?
Is histoplasmosis treatable?
Where is H. capsulatum found?
What can be done to prevent histoplasmosis?
What is histoplasmosis? Histoplasmosis is a disease caused by the fungus Histoplasma capsulatum. Its symptoms vary greatly, but the disease primarily affect the lungs. Occasionally, other organs are affected. This form of the disease is called disseminated histoplasmosis, and it can be fatal if untreated.
Can anyone get histoplasmosis? Yes. Positive histoplasmin skin tests occur in as many as 80% of the people living in areas where H. capsulatum is common, such as the eastern and central United States. Infants, young children, and older persons, in particular those with chronic lung disease are at increased risk for severe disease. Disseminated disease is more frequently seen in people with cancer or AIDS.
How is someone infected with H. capsulatum? H. capsulatum grows in soil and material contaminated with bat or bird droppings. Spores become airborne when contaminated soil is disturbed. Breathing the spores causes infection. The disease is not transmitted from an infected person to someone else.
What are the symptoms of histoplasmosis? Most infected persons have no apparent ill effects. The acute respiratory disease is characterized by respiratory symptoms, a general ill feeling, fever, chest pains, and a dry or nonproductive cough. Distinct patterns may be seen on a chest x-ray. Chronic lung disease resembles tuberculosis and can worsen over months or years. The disseminated form is fatal unless treated.
When do symptoms start? If symptoms occur, they will start within 3 to 17 days after exposure; the average is 10 days. Is histoplasmosis treatable? Yes. Antifungal medications are used to treat severe cases of acute histoplasmosis and all cases of chronic and disseminated disease. Mild disease usually resolves without treatment. Past infection results in partial protection against ill effects if reinfected.
Where is H. capsulatum found? H. capsulatum is found throughout the world and is endemic in certain areas of the United States. The fungus has been found in poultry house litter, caves, areas harboring bats, and in bird roosts.
Pneumocystis jiroveci (previously classified as Pneumocystis carinii) was previously classified as a protozoa.  Currently, it is considered a fungus based on nucleic acid and biochemical analysis.

9. Multicellular Parasites
Arthropods and helminths medically important
Arthropods do (most) damage as vetctors
Helminths cause direct damage to host
At right: Tapeworm in horses intestine.

10. Arthropods
Arthropod borne diseases - Mechanical vectors (flies etc.) vs. biological vectors
Insects: Mosquitoes, fleas and lice
Arachnids: Ticks and mites (mites cause direct disease, e.g.: scabies)
Example diseases
Yellow fever – Mosquito - Flavivirus
Rocky mountain spotted fever – tick – Rickettsia
Other “famous” examples?
Other “famous” examples of diseases: Malaria, Plague and Lyme disease

11. Scabies skin mite is about 0.4mm, just visible to the human eye
Allergic itchy rash
Scabies skin mite is about 0.4mm, just visible to the human eye
Scabies skin mite is about 0.4mm, just visible to the human eye
Sarcoptes scabei mite is about 0.4mm, just visible to the human eye
but the rash and itch are much more widespread than the location of the mites.
The mite may be passed easily by close contact and commonly starts at the wrist, presumably having been picked up through holding hands. Scabies is an infestation of the skin with the microscopic mite Sarcoptes scabei. Infestation is common, found worldwide, and affects people of all races and social classes. Scabies spreads rapidly under crowded conditions where there is frequent skin-to-skin contact between people, such as in hospitals, institutions, child-care facilities, and nursing homes.
Fomite = An inanimate object or substance that is capable of transmitting infectious organisms from one individual to another.

12. Helminths Three groups of helminths relevant to medicine
Nematodes (roundworms): GI tract or blood infections
Cestodes (tapeworms)
Trematodes (flukes)
Three modes of human invasion:
- Skin penetration
- Contaminated food
- Insect vector
Under control in developed countries, millions of deaths / year in underdeveloped countries

13. Flat, segmented, scolex with suckers or hooks
No GI tract  direct absorption of nutrients

14. Helminth Diseases Enterobiasis (Nematode - Enterobius vermicularis)
Filariasis (Nematode - Wuchereria bancrofti)
Tapeworm disease (Tania solium)
Swimmer’s itch (Trematode - Cercaria sp.)

15. Enterobiasis
One of the most common parasitic infections of humans. Causative agent: Pinworm (Enterobius vermicularis)
10% to 40% of children (below age 12) are infected.
Adult pinworms are white and are less than one half inch long, with the diameter of a strand of thread. The adult worms live in the colons of human children and feed on human fecal matter.

16. Approximately 120 million people are infected
Approximately 120 million people are infected. 90% are caused by Wuchereria bancrofti. Almost 25 million men suffer from genital disease (most commonly hydrocoele); an estimated 15 million people have lymphoedema or elephantiasis of the leg.

17. In their adult stage, filarial parasites live in the vessels of the lymphatic system, the network of nodes and vessels that maintains the fluid balance between the tissues and the blood, and which is an essential element of the body's immune defence system. The worms live for several years, producing millions of very small, immature larvae, microfilariae, that circulate in the peripheral blood with marked nocturnal periodicity - WHO.
In their adult stage, filarial parasites live in the lymph vessels The worms live for several years, producing millions of very small, immature larvae, microfilariae, that circulate in the peripheral blood with marked nocturnal periodicity.
                  
© The Global Alliance to Eliminate Lym

18. Swimmer’s Itch - Cercarial Dermatitis
The schistosome cercaria (originating in specific snail species) accidentally enters human skin.
Swimmer’s itch cases have been reported from nearly every state. (Most predominant in the north). In addition, swimmer's itch has been reported from more than 30 countries.
Disappears without treatment (after up to 7 days)
The End