COMMON PARASITIC INFECTION

42問 • 9ヶ月前

JHAYS

通報

問題一覧

is the study of protozoan and helminthic parasites of animals and humans

PARASITOLOGY

in which adult or sexual stages reproduce

DEFINITIVE HOST

in which immature stages live

INTERMEDIATE HOST

is the process of cyst formation

ENCYSTMENT

refers to the process by which cysts become trophozoites.

EXCYSTMENT

- unicellular eukaryotes found in a wide range of habitats - majority of it are free living and do not adversely affect humans or animals - some can cause debilitating and deadly diseases.

PROTOZOAN PARASITES

- called a trophozoite - lives within the host,

FEEDING STAGE

- can survive in the environment and is infective to new hosts. - Once ingested by a host, cysts undergo excystment and develop into new trophozoites which resume feeding and reproducing - Trophozoites undergo encystment before leaving the host in the feces, becoming available to infect other hosts.

DORMANT CYST STAGE

- the only ciliate to cause disease in humans. - a relatively large (50 μm × 100 μm) - commonly found in animal intestinal tracts - PIGS are its most common host • also found in RODENTS and NONHUMAN PRIMATES - Humans become infected by consuming food or water contaminated with FECES containing cysts - is responsible for BALANTIDIASIS, usually a mild gastrointestinal illness. - Persistent diarrhea, abdominal pain, and weight loss characterize the disease - Severe infections produce: • dysentery - frequent and painful diarrhea, often containing blood and mucus • ulceration and bleeding from the intestinal mucosa. - Balantidium infection is rarely fatal

BALANTIDIUM COLI

- does not kill B. coli directly but modifies the normal microbiota of the digestive tract such that the small intestine is unsuitable for infection by the ciliate. - Prevention of balantidiasis relies on good personal hygiene, especially for those who live around or work with pigs - efficient water sanitation is necessary - to kill cysts or remove them from drinking water.

TETRACYCLINE

are protozoa that move and feed using pseudopods.

AMOEBA

- a relatively common protozoan parasite - causes amebiasis - can be mild luminal amebiasis, more severe amebic dysentery, or very severe invasive extraintestinal amebiasis - the parasite causes lesions in the liver, lungs, brain, and other organs

ENTAMOEBA HISTOLYTICA

- are protozoa that possess at least one long flagellum, which is used for movement. • number and arrangement of the flagella are important features for determining the species of flagellate present within a hostare protozoa that possess at least one long flagellum, which is used for movement. • number and arrangement of the flagella are important features for determining the species of flagellate present within a host

FLAGELLATES

• transmitted by the kissing bug (Triatoma) • causes Chagas' disease • cause of heart disease • Transmission occurs through the bite of true bugs • Bloodsucking bugs feed preferentially from blood vessels in the lips • gives the bugs their common name-kissing bugs

TRYPANOSOMA CRUZI

• transmitted by the tsetse fly • causes African sleeping sickness • Epimastigotes in the insect gut develop into infective trypomastigotes introduced to the human host by the insect vector • trypomastigotes remain in the blood • Antigenically variable, can spread to the CNS, and can be fatal.

T. BRUCEI

- trypomastigotes develop intracellularly in macrophages and heart muscle as amastigotes

T. CRUZI

frequent cause of gastrointestinal disease • Cysts are immediately infective upon release • leading to a significant incidence of person-to-person and self-to-self transmission. • Cysts survive and remain infective for several months • watery diarrhea, abdominal pain, bloating, nausea, vomiting, ineffective absorption of nutrients, and low-grade fever • Stools are foul smelling • "rotten-egg" smell • Incubation lasts roughly one to two weeks, and symptoms resolve after one to four weeks in normal. health adults

GIARDIA INTESTINALIS

- is rarely fatal environment because of the protective outer shell of its cyst. - Infection usually results from the ingestion of cysts in contaminated drinking water or accidental ingestion during swimming. - Hikers, campers, and their pets are at particular risk because infected wild animals shed Giardia into mountain stream • Cysts are immediately infective upon release • leading to a significant incidence of person-to-person and self-to-self transmission. • Cysts survive and remain infective for several months • watery diarrhea, abdominal pain, bloating, nausea, vomiting, ineffective absorption of nutrients, and low-grade fever • Stools are foul smelling • "rotten-egg" smell • Incubation lasts roughly one to two weeks, and symptoms resolve after one to four weeks in normal. health adults

GIARDIASIS

• the most common protozoan disease of humans. • sexually transmitted protozoan • causes vaginosis • Prevention: • Abstinence • Monogamy • condom usage purulent (pus-filled) odorous discharge • vaginal and cervical lesions • abdominal pain • painful urination • painful intercourse

TRICHOMONAS VAGINALIS

Five species • falciparum • vivax • ovale • malariae • knowlesi • cause malaria • female Anopheles mosquitoes • 3 stages of the life cycle of Plasmodium • Sporozoites travel to the liver to initiate the exoerythrocytic phase • Rupture of liver cells releases merozoites from intracellular schizonts • Merozoites infect erythrocytes to initiate the erythrocytic cycle • sporogonic phase in the mosquito has an oocyst that divides to form sporozoites, which are injected into humans when the mosquito feeds

PLASMODIUM

PLASMODIUM generally causes mild disease

P. OVALE

PLASMODIUM usually results in chronic malaria, with periodic recurrence of symptoms

P. VIVAX

PLASMODIUM cause more serious malaria

P. MALARIAE, P. FALCIPARUM

PLASMODIUM • fatal • causes a form of malaria called blackwater fever

P. FALCIPARUM

are produced by P. ovale and P. vivax

DORMANT HYPNOZOITES

produces the deadliest form of malaria

P. FALCIPARUM

- ingesting undercooked meat containing the parasite - People at greatest risk - butchers, hunters, and anyone who tastes food while preparing it. - Ingestion or inhalation with contaminated soil - Generally mild in humans, but it can cross the placenta to cause serious harm to fetuses - Wild and domestic mammals and birds - are major reservoirs for it, and cats are the definitive host - in which the protozoan reproduces sexually

TOXOPLASMA GONDII

are multicellular eukaryotic worms, some of which are parasitic

HELMINTHIC PARASITES

• scolex • attaches it to the intestine of its definitive host • From this extends a neck region from which proglottids grow • When fertilized eggs (sometimes within gravid proglottids) are eaten by an intermediate host, they hatch to release Larval stages that invade tissues of the intermediate host and form cysticerci • When the cysticerci are eaten by a definitive host, they undergo development into adult.

TAPEWORMS

Humans are the definitive hosts ________ • Beef tapeworm _________ • pork tapeworm • Humans become infected by eating cysticerci in undercooked beef or pork

TAENIA SAGINATA, TAENIA SOLIUM

• forms hydatid cysts • cause hydatic disease in humans • accidental intermediate hosts when they ingest the helminth's eggs • definitive host • canine • it body consist of only three proglottids—- one immature, one sexually mature, and one Gravid • gravid proglottid is released each time the neck forms a new immature proglottid • Humans become accidental intermediate hosts by consuming foods or water contaminated with Echinococcus eggs shed in dogs feces • The eggs release larvae into the intestine • the larvae invade the circulatory system and are carried throughout the body, where they form hydatid cysts and cause hydatid disease • Hydatid cysts form in any organ but occur primarily in the liver.

ECHINOCOCCUS GRANULOSUS

- or flukes - are often divided into four groups: - blood, intestinal, liver, and lung flukes - Eggs deposited in water hatch to release miracidia, which burrow into freshwater snails - Following asexual reproduction cercariae are released into the water - In intestinal, liver, and lung flukes, cercariae encyst on plants or in a second intermediate host as metacercariae, which are ingested by human hosts. - Cercariae of blood flukes directly penetrate the skin of humans. After maturation occurs in the human, flukes release eggs back into the environment via the feces or urine

TREMATODES

• a liver fluke • Humans acquire Fasciola hepatica by ingesting metacercariae on watercress or other vegetables. • Diagnosis involves the correlation of symptoms and patient history with microscopic identification of eggs in fecal matter

FASCIOLA

• blood flukes • causing schistosomiasis. • common name for the disease is "snail fever," • Three species infect humans: • S. mansoni -is common to the Caribbean Venezuela, Brazil, Arabia, and large areas of Africa. • S. haematobium - found only in Africa and India. • S. japonicum - occurs in China, Taiwan, the A Figure 23.21 sample. Distinctiv Philippines, and Japan, although infections in Japan are relatively rare • Extensive infections significantly damage the liver. - Humans are the principal definitive host - Cercariae burrow through the skin of humans who contact contaminated water while washing clothes and utensils, bathing, or swimming - The larvae enter the circulatory system, where they mature and mate

SCHISTOSOMA

- Are round, unsegmented worms with pointed ends - Most intestinal nematodes shed their eggs into the lumen of the intestine, where they are eliminated with the feces - eggs are then consumed by the definitive host either in contaminated food (particularly raw fruits and vegetables that grow close to the soil) or in contaminated drinking water

NEMATODES

• the largest nematode to infect humans • Ascariasis • the most common nematode disease of humans in the world. • Eggs containing infective larvae are consumed with contaminated vegetables • The eggs hatch in the intestine, and larvae enter the lymphatic system. • Worm migration through the body may be associated with various symptoms, but infections are usually not fatal. • Growing as large as 30 cm in length • After eggs are ingested in water or on vegetables, the larvae invade the intestinal wall to enter the circulatory or lymphatic systems • From there the larvae reach the lungs, where they develop through two more larval stages in approximately two weeks • Worms are then coughed up into the pharynx and swallowed • The parasites subsequently develop into adults in the intestine.

ASCARIS LUMBRICOIDES

• both hookworms, • the second most common nematodes to infect humans Worldwide • Eggs deposited in soil mature to form infective larvae that leave the egg and actively burrow through human skin to initiate infection. • The circulatory system carries the worms through the lungs and heart. • Eventually worms migrate up the respiratory tract to the pharynx, where they are swallowed. • They become adults in the intestine, where they attach to the intestinal mucosa and feed on blood. • Hookworm infection can lead to anemia and other A Figure 23.23 Mouth of a hook parasite to attach to the intestinal wall blood-related dysfunction.

ANCYLOSTOMA DUODENALE

- Pinworm - the most common parasitic worm infestation of humans in the United States and the third most common in the world - Eggs deposited in the perianal area are introduced into the mouth following scratching to reinfect the human host. - Transmission among family members is also common. - Humans are the only host for Enterobius - After mating in the colon, female pinworms migrate at night to the anus, where they deposit eggs perianally. Scratching dislodges eggs onto clothes or bedding, where they dry out, become aerosolized, and settle in water or on food that is then ingested. scratching deposits eggs on the skin and under the fingernails such that infected individuals can continually reinfect themselves by ingesting the eggs on their hands or in food. - Adult worms mature in several weeks and live in the intestinal tract for approximately two months. - intense perianal itching is the chief complaint - Scratching can lead to secondary bacterial infections

ENTEROBIUS VERMICULARIS

• is a filarial (threadlike) nematode of humans, causing filariasis • lives in the lymphatic system, where adult worms block lymph flow, causing elephantiasis • Lymph accumulates, especially in the lower extremities • Bacterial infections may ensue, and subcutaneous tissues harden, producing permanent disfigurement • The parasite is transmitted when microfilariae, which circulate in the blood, are picked up by feeding mosquitoes.

WUCHERERIA BANCROFTI

- are organisms with segmented bodies, jointed legs, and a hard exoskeleton - They are found worldwide in nearly all habitats - Some may serve as biological vectors for many organisms.

ARTHROPODS

VECTORS include mites and ticks.

ARCHANID

VECTORS fleas, lice, flies, and kissing bugs.

INSECT

HCI

HCI

TERMS

TERMS

HEALTH DEF

HEALTH DEF

ANAPHY PRELIMS REVIEW

JHAYS · 43問 · 1年前

ANAPHY PRELIMS REVIEW

INTEGUMENTARY SYSTEM

INTEGUMENTARY SYSTEM

BIOCHEM

BIOCHEM

SKELETAL SYSTEM

SKELETAL SYSTEM

joints

joints

muscle and joint movements

JHAYS · 17問 · 1年前

muscle and joint movements

MUSCULAR SYSTEM

MUSCULAR SYSTEM

LIPIDS

LIPIDS

NEUROTRANSMITTER

NEUROTRANSMITTER

NERVOUS

NERVOUS

NERVOUS PART 2

NERVOUS PART 2

SPECIAL SENSES

SPECIAL SENSES

ENDOCRINE SYSTEM

ENDOCRINE SYSTEM

問題一覧

is the study of protozoan and helminthic parasites of animals and humans

PARASITOLOGY

in which adult or sexual stages reproduce

DEFINITIVE HOST

in which immature stages live

INTERMEDIATE HOST

is the process of cyst formation

ENCYSTMENT

refers to the process by which cysts become trophozoites.

EXCYSTMENT

- unicellular eukaryotes found in a wide range of habitats - majority of it are free living and do not adversely affect humans or animals - some can cause debilitating and deadly diseases.

PROTOZOAN PARASITES

- called a trophozoite - lives within the host,

FEEDING STAGE

DORMANT CYST STAGE

BALANTIDIUM COLI

TETRACYCLINE

are protozoa that move and feed using pseudopods.

AMOEBA

ENTAMOEBA HISTOLYTICA

FLAGELLATES

TRYPANOSOMA CRUZI

T. BRUCEI

- trypomastigotes develop intracellularly in macrophages and heart muscle as amastigotes

T. CRUZI

GIARDIA INTESTINALIS

GIARDIASIS

TRICHOMONAS VAGINALIS

PLASMODIUM

PLASMODIUM generally causes mild disease

P. OVALE

PLASMODIUM usually results in chronic malaria, with periodic recurrence of symptoms

P. VIVAX

PLASMODIUM cause more serious malaria

P. MALARIAE, P. FALCIPARUM

PLASMODIUM • fatal • causes a form of malaria called blackwater fever

P. FALCIPARUM

are produced by P. ovale and P. vivax

DORMANT HYPNOZOITES

produces the deadliest form of malaria

P. FALCIPARUM

TOXOPLASMA GONDII

are multicellular eukaryotic worms, some of which are parasitic

HELMINTHIC PARASITES

TAPEWORMS

Humans are the definitive hosts ________ • Beef tapeworm _________ • pork tapeworm • Humans become infected by eating cysticerci in undercooked beef or pork

TAENIA SAGINATA, TAENIA SOLIUM

ECHINOCOCCUS GRANULOSUS

TREMATODES

FASCIOLA

SCHISTOSOMA

NEMATODES

ASCARIS LUMBRICOIDES

ANCYLOSTOMA DUODENALE

ENTEROBIUS VERMICULARIS

WUCHERERIA BANCROFTI

- are organisms with segmented bodies, jointed legs, and a hard exoskeleton - They are found worldwide in nearly all habitats - Some may serve as biological vectors for many organisms.

ARTHROPODS

VECTORS include mites and ticks.

ARCHANID

VECTORS fleas, lice, flies, and kissing bugs.

INSECT