Chapter 34

How can malaria be prevented or eradicated?

-Several vaccines are currently in development -Can be controlled by draining swamps or eliminating mosquitoes -Drugs are used to prevent and treat infections

From what source are most cases of human trichinosis contracted?

-Worm lives in muscle tissue of wild mammals -Worm infects pigs -Humans consume undercooked meat -Larvae enter intestinal mucosa -Larvae can circulate throughout body

What symptoms of giardiasis would suggest that your gastroenteritis was not due to a bacterial pathogen?

-explosive, foul-smelling diarrhea, intestinal cramps, nausea, weight loss, and malaise -many individuals exhibit no symptoms and can act as carriers

How does one contract a case of trichomoniasis?

-transmitted person-to-person by sexual intercourse -can be transmitted by toilet seats, sauna benches, and towels

How does one contract a case of toxoplasmosis?

-transmitted to humans through fecally contaminated food or water -The oocysts are transmitted by cats -also by undercooked meat

Why do those suffering from HIV/AIDS often show secondary fungal infections of major internal organs?

Because HIV weakens the immune system, you have a greater chance of getting some types of fungal infections. (already have a preexisting condition)

-a pathogenic protist transmitted to humans primarily through contaminated water and sometimes food -anaerobic and produces resistant cysts -asymptomatic or lead to diarrhea and/or dysentery -intestinal inflammation, fever, and the passage of intestinal blood and mucus, which often leads to anemia -if untreated, invasive cells can invade the liver and occasionally the lungs and brain -can be treated with amoebicidal drugs

Entamoeba histolytica

How are sleep patterns altered in cases of African trypanosomiasis?

Human African trypanosomiasis (HAT) associated meningoencephalitis leads to progressive neurologic involvement with concomitant neuropsychiatric disorders, fragmentation of the circadian sleep-wake cycle, and eventually death. Transmitted by bite of tsetse fly. Parasite multiplies in blood and infects central nervous system and multiplies in spinal fluid. Treatment includes anti-trypanosomal drugs.

a disease of the skin or viscera caused by infection with species of a parasitic flagellated protozoan, Leishmania

Leishmaniasis

a disease characterized by recurrent episodes of fever and anemia; caused by species of the protist Plasmodium, usually transmitted between mammals through the bite of the Anopheles mosquito

Malaria

the invasion, inflammation, and destruction of brain tissue by the amoeba Naegleria fowleri or a variety of other pathogens

Meningoencephalitis

any infection caused by a fungus

Mycosis

-A free-living amoeba found in soil and water runoff -Enters the human body through the nose and burrows directly into the brain, causing extensive hemorrhage and brain damage -primary amebic meningoencephalitis -Drug treatment is effective if infections are identified early

Naegleria fowleri

What is unusual about the oocysts of Cryptosporidium that facilitates it transmission by a water route?

Oocysts are highly resistant to chlorine and U V radiation; thus, sedimentation and filtration methods are most effective at removal.

-Called snail fever -Caused by the trematode Schistosoma -Life cycle requires snails and humans -Eggs released into freshwater -Eggs become miracidia -Miracidia infect snails and become cercaria -Cercaria burrow into skin, leaving surface lesions -Occurs in tropical and subtropical countries -Treatment with praziquantel

Schistosomiasis

a chronic disease caused by a parasitic worm that leads to internal organ damage and accumulation of fluids and worm egg masses

Schistosomiasis

-Situations where fungi colonize deeper layers of skin tend to be more serious than superficial fungal infections -Different groups of fungi may cause this infection: Sporothrix Fonsecaea Cladosporium

Subcutaneous mycoses

fungal infections of deeper layers of skin

Subcutaneous mycoses

-Caused by dermatophytes -Fungi that colonize the hair, skin, or nails and infect only the surface layers

Superficial mycoses

fungal infections of the surface layers of skin, hair, or nails

Superficial mycoses

Give an example of a superficial, a subcutaneous, and a systemic mycosis.

Superficial: athlete's foot Subcutaneous: sporothrix Systemic: histoplasmosis

-Humans become infected by inhaling spores -Fungal growth in internal organs of the body

Systemic mycoses

fungal growth in internal organs of the body

Systemic mycoses

Which stages of the Plasmodium life cycle occur in humans?

The life cycle of plasmodium in a human is as follows: Transmission by bite of mosquito. Sporozoites removed from blood by liver. Exoerythrocytic stage, Formation of schizont and merozoites in the liver. Infection of a red blood cell. Erythrocytic stage, merozoites infect and reproduce in red blood cells. Symptoms of malaria occur in this stage. Production of gametocytes.

Which stages of the Plasmodium life cycle occur in mosquitos?

The life cycle of plasmodium in a mosquito is as follows: Transmission by bite of mosquito Maturation of gametes within mosquito Fertilization Growth Development of sporozoites Release of sporozoites

How are trypanosome disease similar to malaria and how do they differ?

They are different in that malaria has a complex life cycle and acute forms of malaria can be deadly. Trypanosome diseases are spread by tsetse flies and "kissing bugs," while malaria is spread only by the Anopheles mosquito. Parasite affects heart, gastrointestinal tract, and central nervous system and occurs in Latin American countries. Both trypanosome diseases and malaria are caused by protozoa and are spread by insect vectors. Both parasites multiply in the blood and in some cases affect the nervous system and other organs. There are no effective vaccines for trypanosome diseases or malaria

any parasitic disease of the blood and internal tissues caused by species of the flagellated protozoan Trypanosoma; African sleeping sickness and Chagas disease are two major trypanosomiases

Trypanosomiasis

What are the natural reservoirs and vectors for Plasmodium species?

Vectors: Anopheles mosquitoes Reservoir: Humans

Why are systemic fungal pathogens called opportunistic?

antibiotic use disrupts the normal microbiota, often leading to fungal overgrowth Opportunistic fungi refers to those fungi that normally would not cause infections in otherwise healthy people but are able to cause infection under certain circumstances such as immunodeficiency, cancer, organ transplant, neutropenic patients, diabetes, debilitated patients and patients on long term antibiotics.

What drugs are used to treat malaria?

chloroquine and primaquine

-Leishmania tropica or L. mexicana -flagellated protozoan -related to Trypanosoma -transmitted by bite of sandfly -infects and grows in macrophages -forms nodules and ulcers on skin -treatment with antimony compounds

cutaneous leishmaniasis

meaning they can be either molds or yeasts

dimorphic fungus

Fungal infection that occurs when an otherwise normal, healthy individual is infected with the fungal pathogen; these are rather uncommon.

primary fungal disease

Fungal infection that occurs in a host that harbors a predisposing condition, such as antibiotic therapy or immunosuppression, that makes the individual more susceptible to infection.

secondary fungal disease

Describe a scenario for contracting a Naegleria infection.

swimming in warm, soil contaminated natural water sources

-Leishmania donovani -transmitted by bite of sandfly -parasite travels to internal organs -damage to liver, spleen, and bone marrow -if untreated, visceral disease is fatal -treatment includes pentavalent antimony (S b5+), bed rest, and blood transfusions

visceral leishmaniasis