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202 Cards in this Set

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  • Back
What are the four general points to bear in mind when diagnosing a patient?
1. Oversease travel
2. Parasite might be present without causing disease
3. Effects of parasite depend on age, health, previous exposure, infective dose other infections.
4.Need stool samples for suspected gut parasites.
What two major type of parasite come under intestinal parasites?
Intestial Protozoa and Helminths.
What are the three subcategories under Helminths that can be classifed as intestinal parasites?
Nematodes (round worms), cestodes (tapeworms) and trematodes (flukes).
What are the five types of intestinal protozoa?
Giardia lamblia, Entamoeba histolytica, Cryptpsporidium parvum, Balantidium coli, Blastocystis spp.
Where is Giardia lamblia found? What is special about it?
In duodenum.
Most common intestinal protozoa.
What is the shape of the trophozoite of Giardia lambila?
Pear shaped with double nucleus and four pairs of flagellae with a ventral sucking disc.
How does is multiple? In which forms?
Asexual, both motile (trophozite) and cystic forms.
What systems does Giardia lambila cause?
Diarrhoea, stomach cramps, loss of appetite and nausea.
How can Giardia lambila be prevented?
Good personal hygiene, clean water supplies, careful food preparation.
What is the treatment for Giardia lamblia?
Metronidazole or Tinidazole.
What is Entamoeba histolytica a major cause of? What is the other major cause of this?
Dysentry.
Shigella species.
Where are the trophozites of Entamoeba histolytica found?
Large intestine, mainly ceacum and colon.
How does Entamoeba histolytica cause disease?
The trophozites feed on the mucosal surface of the intestine causing ulcers which lead to profuse bloody and mucous diarrhoea and considerable fluid loss.
What is different about Entamoeba histolytica from other gastrointestinal protozoa?
It is invasive-by haematogenous or direct spread from colon gives rise to abscesses in liver, lungs and other organs.
What is the treatment for Entamoeba histolytica?
How can it be prevented?
Metronidazole or tinidazole.
Good hygiene and safe water and food supplies.
Where are Cryptosproidium parvum located?
Within brush border cells of the gut.
How do Cryptosporidium parvum reproduce?
Sexually.
Where are reservoirs for Cryptosporidium parvum found?
In animals-hence zoonotic infection.
What type of symtpoms does Cryptosporidium parvum produce? What treatment is required?
Produces nausea, loss of appetite, watery diarrhoae and vomiting. It is self-limiting so no treatment required.
How can Cryptosporidium parvum be prevented?
Good hygiene, especially when handling domestic animals.
What is the only ciliate of importance to humans?
Balantidium coli
What animal is the infection of Balantidium coli commonly associated with?
Pigs
What are the four forms the Blastocystis spp. may take?
Vacuolar, granular, amoeboid and cyst.
How does the life cycyla of the Blastocystis spp begin? How is it transferred between humans?
Ingestion of the cyst form.
Faecal-oral route.
How much faeces is required to make a significant smear when diagonosing?
2mg
What are the six important intestinal nematodes?
Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichuria, Hookworms, Strongyloides stercoralis, Trichinella spiralis.
What is Ascaris lumbricoides also known as?
Common roundworm.
What is the distriubtion of Ascaris lumbricoides?
World-wide; humid tropical climates.
What is the morphology of the adult Ascaris lumbricoides? What is the morphology of their eggs?
Cylindrical, whitish, 15-30cms long.
Brown and ovoid.
Where is the adult Ascaris lumbricoides found and what is its life span?
Upper part of small intestine and one year.
How do the Ascaris lumbricoides eggs mature and what parts of the body do they do this in?
Larvae emerge from eggs in duodenum, penetrate gut wall, and carried by blood stream to the lungs. After several days there they break out into the alveoli, moult twice, ascend trachea and pass down oesophagus to mature in intestine.
How long does the maturation cycle take in Ascaris lumbricoides?
8 weeks
How is Ascaris lumbricoides acquired?
Ingestion of fully embryonated eggs which have been picked up from imfected soil or as food contaminants.
What symptoms are derived from the Ascaris lumricoides migrating larvae?
What symptoms occur due to the adult worms?
Those to do with lung-pneumonitis and fever.
Often no symtpoms, abdominal discomfort, or acute colicky pains. Often poor digestion and diarrhoea. Ascaris metabolites can cause sensitising phenomena, eg urticaria, asthma and conjuctivitis.
What is the treatment for Ascaris lumbricoides?
Mebendazole, albendazole (except in pregnancy), combantrin.
How may Ascaris lumcroides be prevented?
Clean sanitary and toilet facilities and personal hygiene.
What is another name for Enterobius vermicularis?
Pinworm, or threadworm.
What is the distribution of Enterobius vermicularis?
Cosmopolitan, but more common in temperate regions.
What is the morphology of the adult Enterobius vermicularis?
Spindle shaped worms, males up to 5mm, females up to 13mm.
Where do the adult Enterobius vermicularis inhabit?
Caecum and appendix and adjoining gut, with heads attached to mucosa.
Where does the gravid Enterobius vermicularis female go after detaching from mucosa? When does this occur? How many eggs are laid?
Perinanal skin.
At night.
Up to 11,000 eggs.
How long does it take for Enterobius vermicularis eggs to become infective?
6 hours
How do the immature Enterobius vermicularis mature inside the body? How long does this cycle take?
Ingested via muth, and first stage larvae released into bowel with moulting en route.
6 weeks.
How is Enterobius vermicularis transmitted?
1. direct anus-to-mouth by finger contamination, or night clothes
2. exposure to viable eggs on room furniture, door handles, etc
3. air-borne from bed-linen being aired
What patholoy does Enterobius vermicularis cause?
Minute intestinal ulcerations, pruritus ani (irritation of skin at rectum) which may cause haemorrhage and eczema.
How is diagnosis of Enterobius vermicularis made?
Characteristi history of itching, eggs in perinanal scraping, or in fingernail scrapings. Adult worms found in stools after enemas.
What is the treatment for Enterobius vermicularis? How may it be prevented?
Combantrin, mebendazole, albendazole.
Mainly personal hygiene.
What is Trichuris trichiura also known as?
Whipworm.
What is the distrubtion of Trichuris trichiura?
World-wide, more common in humid tropical regions.
What is the morphology of adult Trichuris trichiura? Eggs?
Adult workms are pinkish-white, thin in anterior 3/5 and thick in posterior 2/5. Posterior end is coiled in males. 3-5cms long.
Barrel-shaped with mucus plug at each end.
Where do adult Trichuris trichiura live in the human?
Attached to caecum.
How many days is required for embryonation of Trichuris trichiura in soil? What else is essential for their development?
10-14 days.
Moisture.
What is the life cycle of the Trichuris trichiura in the human body? How long does it take for the Trichuris trichiura to mature?
Infection from swallowing embryonated eggs, shells digested off in intestine and larave go to crypts for protection, later passing to sites of adult attachment.
Three months.
How is Trichuris trichiura contracted?
Infection by mouth from contaminated hands or food.
What are the symptoms of Trichuris trichiura?
Generally no symtpoms, but in heavy infections there is damage to caecal mucosa causing apendicits. Also may cause colitis, anaemia from chronic blood loss, dysentry, abdominal pains, vomiting and constipation.
How is Trichuris trichiura diagnosed?
If severe resembles hookworm, appendicites or amoebic dysentery. Typical eggs in faeces.
How is Trichuris trichiura treated? How is it prevented?
Mebendazole or albendazole.
Sanitation and personal hygiene.
What are the two species of Hookworms?
Ancylostoma duodenale (mainly old world) and Necator americanus (new world)
What is the distribution of Ancylostoma duodenale and Necator americanus? What % of the world's population may be infected?
Very widespread. Present in same regions as malaria and malnutrition.
25%
What is the morphology of Ancylostoma doudenale and Necator americanus adults and eggs?
Adults about 10mm long and eggs are thin-shelled.
Where do Ancylostoma doudenale and Necator americanus adults live? What happens to the eggs?
Small intestine.
Passed out in faeces, hatch 24-48hrs later and first stage moult twice to 3rd stage larvae where remain infective in soil for weeks.
How do Ancylostoma duodenale and Necator americanus infect humans?
Directly through mouth or penetrating the skin.
How do Ancylostoma duodenale and Necator americanus enter system via entry through skin?
Pass to venules and carried via right heart to lungs where they break out into alveoli, migrate up bronchioles, bronchi and trachea, down oesophagus and into the intestine.
How long does maturity of Ancylostoma duodenale and Necator americanus take?
5 weeks.
How is Ancylostoma duodenale and Necator americanus spread?
Defacation habits of people, suitable habitat for larval development, chance for larvae to reach skin.
What are the resulting pathologies of Ancylostoma duodenale and Necator americanus?
1. infection: general allergic reactions
2. migration: lung involvement, pneumonitis
3. localisation: iron-deficient anaemia resulting in constipation, oedema.
How do Ancylostoma duodenale and Necator americanus cause anaemia?
Ingestion of blood by worms with occult bleeding from intestinal mucosa.
How is Ancylostoma duodenale and Necator americanus diagnosed?
'Ground itch' at site of entry of larvae, eggs in faeces.
How is Ancylostoma duodenale and Necator americanus treated? How is it prevented?
Mebendazole, Albendazole, Alcopar and Fee tablets if patient is anaemic.
Good, sanitary habits and general hygiene.
What is the distribution from Strongyloides stercoralis?
Mostly warm climates; similar to hookworms.
What is unique about Strongyloides stercoralis as a nematode?
Both parasitic and free-living generations. Is able to multiply in body.
Where do the free-living Strongyloides stercoralis worms live and how long for? When do they become parisitic and what occurs?
In the surface soil and indefinitely.
When conditions are unfavourable they metamorphose into infective filariform larvae.
How do the Strongyloides sterocoralis larvae infect the human? Where may fertilisation occur?
Penetrate the skin and are carried by blood via heart to lungs where they moult to become adolscent worms.
In alveoli, trachea or intestine.
Where do the adult female Strongyloides sterocolaris lay their eggs? Where do the larvae go once hatched in bowel mucosa?
In the bowel mucosa.
Into the intestine.
What is special about female Strongyloides sterocolaris?
They may mature parthenogenetically in man.
What may occur to Strongyloides stercoralis larvae once hatched?
They may pass out in faeces or moult to an infective stage within the bowel re-invading the mucosa and travel via lungs to intestine again. This is auto-infection.
How may Strongyloides stercoralis re-infect the human?
Via perianal skin.
What animal can harbour Strongyloides stercoralis? How long after the original infection may symptoms persist and why?
Dogs.
Decades due to auto-infection.
What symtpoms arise as a result of Strongyloides stercoralis?
1. Invasion: local dermatitis, localised pneumonitis, generalised allergic reactions, eosinophilia.
2. Adults: inflammation of intestinal mucosa, with diarrhoea and abdominal pain.
How is a diagnosis for Strongyloides stercoralis made?
Diarrhoea with mucus and abdominal pain. Larvae found fresh in faeces.
What is the treatment for Strongyloides stercoralis? How may it be prevented?
Thiabendazole, albendazole. May require repeated courses.
With individual and mass population good sanitary habits and general hygiene.
What is trichinosis caused by?
Trichinella spiralis.
What is the distribution of Trichinella sprialis?
Worldwide especially E. Europe, Russia, N. America and parts of Africa and S. America. Not endemic in Aus.
Where are the Trichinella spiralis worms found?
Embedded in ileal mucosa.
What is special about how the larvae are formed in Trichinella spiralis?
Female gives birth to larvae.
Where are Trichinella spiralis larave deposited by viviparous mother? Where do they encyst, and how do they get there?
Ileal mucosa.
Travel via lymphatics and blood vessels to skeletal muscles.
How are Trichinella sprialis contracted? What is the main source of infection in most areas?
Eating insufficiently cooked meat containg encysted larvae.
Pigs.
What is the pathology of Trichinella spiralis?
Eosinophilia, fever, swelling of eyeldes, muscle tenderness. May be sudden onset with nausea, vomiting and diarrhoae.
How is diagnsosi of Trichinella spiralis made?
Very high eosinophila with associated history and symtpoms, biospy of biceps or gastrocnemius muscle for cysts, or serological and immunological test.
How can Trichinella spiralis be prevented? How can it be treated?
Laws preventing feeding of garbae to pigs, cook meat well.
Steroids, thiabendazole and mebendazole.
Where are the two most common human infections with non-human nematodes from? What condition do they cause and why?
Cats and dogs.
'Larva migrans' as worms can not mature in humans.
What is the name of the large roundworm of dogs? What does it cause?
Toxocara canis.
Visceral larvae migrans.
What symptoms do Toxocara canis produce? How is the diagnosis made?
Liver tenderness, occassionally abnormal liver function tests, eosinophilia and very rarely infect eye.
By serological test.
What is the name of the hookworms of cats and dogs? What does it cause? What are the syptoms and why?
Ancylostoma braziliense.
Cutaneous larva migrans.
Raised, red, itchy trail in skin as they can unable to penetrate deeply.
What are the five important Cestodes? What are Cestodes also known as?
Echinococcus granulosus, Taenia saginata, Taenia solium, Hymenolepis nana, Diphyllobothrium latum.
Tape worms.
In what state do all tapeworms ocur in the digestive tract?
Adult.
What does Echinococcus granulosus cause? Where does it priniciapply occur?
Hydatid disease.
Where sheep are reared.
How many hosts does Echinococcus granulosus require? What is the host before human and herbivores? How does it enter a human?
Two.
Dogs.
Via eggs from adults in dog which are passed out in faeces.
Onced ingested bu human or herbivore what happens to Echinococcus granulosus eggs?
Hatch into a six-hoked larvae (oncosphere) which penetrates the intestine and is carried via blood to liver and lungs.
What happens to the larvae of Echinococcus granulosus once reach liver or lungs?
Form a small cyst in which oncospheres may multiply which enlarges the cyst overtime.
How can Echinococcus granulosus be prevented?
What is the treatment for it?
Regular treatment of all dogs for adult worms, avoid feeding offal to dogs and personal hygiene.
Mebendazole or albendazole reduce size of cyst but do not kill oncospheres. Surgery for cyst removal.
What is Taenia saginata known as? Where do the adults live and how long may they get?
Beef tapeworm.
Small intestine and five or more metres.
What are the adult Taenia sanginata divided into? What do the divisions produce?
Proglottids (segment of tapeworm with male and female reproductive organs)
Eggs passed into the faeces which may contaminate pasture.
Once contaminating pasture what may occur to Taenia sanginata? What happens after this and where?
Ingested by cattle.
Oncosphere larvae hatch in the duodenum,burrow into the intestinal wall, and finall lodge in muscles.
Upon lodging in muscles what type of larvae do Taenia saginata form? How may they get into the human? What occurs to them in the human?
Infective cysticercus larave.
Under-cooked infective meat.
Form adults.
What are the symptoms of Taenia saginata in humans? How is it diagnosed? How may it be prevented? How is it treated?
Mobile proglottids crawling through the anus.
Via eggs of proglottids in faeces.
Veterinary meat inspection, safe faeces disposal, well cooked beef.
Treate with niclosamid or praziquantel.
What is Taenia solium also known as?
Pork tapeworm.
Although the life cycle of Taenia solium is similar to the beef tapeworm how can it differ? What happens when this occurs?
Man can become the intermediate host when food, water etc is contaminated with pig faeces.
Cysticerci lodge in tissues of the body including mucles and most seriously, the brain.
How is diagnosis of Taenia solium made? How is it prevented?
Eggs or proglottids in faeces.
Cysticercosis when calcified by radiology, CT scans and serological test.
Hygiene,meat inspection, education, well-cooked meat in endemic areas.
What is Hymenolepis nana known as? Why is it important to an Australian physician?
Dwarf tapeworm.
Most common tapeworm in Australia, and 2nd most common parasite in Aboriginal children.
What are most Hymenolepsis nana infections? What may be involved as an intermediate and zonnotic host?
Direct.
Beetles and mice.
How is Hymenolepsis nana diagnosed? What is its treatment? How is it prevented?
Characteristic eggs in faeces.
Praziquantel or niclosamide.
Good hygiene and clean water supplies.
What is Diphyllobothrium latum also known as? Where does it occur principally?
Fish tapeworm.
Europe, Russia and N. America.
What is the first intermediate host of Diohyllobothrium latum? What happens if the crustacean is eaten by a fish? How does many become affected?
Crustacean.
Debelopes into sparganum larvae in tissues.
Eaten undercooked fish.
What may infection by Diphyllobothrium latum cause in humans? How does it do this?
Megoblastic anaemia due to absorption of vitamin B12 from the gut.
How is Diphyllobothrium latum diagnosed? How is it prevented?
Typical eggs in faeces and occassionaly proglottids are passed.
Faeces disposal, well-cooked fish.
Niclosamide or praziquantel.
What other cestodes may rarely cause infection in man and in which countries?
Echinococcus mulilocularis in northern Russia and N. America and Hymeolepis diminuta.
What are trematodes also know as?
Flukes or digenae.
What do all trematodes have as a first intermediate host? Which trematodes do not have a second intermediate host?
Mollusc.
Schistosomes.
Where may flukes inhabit in the human?
Blood stream, intestine, lungs and hepato-biliar system.
What are the names of the intestinal trematodes?
Opisthorchis sinensis, Fasciola hepatica, Paragonimus westernmani, Fasciolopsis buski.
What other names is Opisthorchis sinensis known as?
Oriental liver fluke and Clonorchis sinensis.
Where do the adult worms of Opisthorchis sinensis reside? How are Opisthorchis sinensis eggs passed to first intermediate host? What happens once they have passed to intermediate host?
Biliary passages.
Through faeces which are ingested by first intermediate host.
Asexual multiplication.
What emerges from the Opsithrochis sinensis eggs in the snail? What happens to them when they exist snail?
Cercariae.
Encyst beneath scales of various species of freshwater fish.
What happens if fish containg cercariae of the Opisthorchis sinensis are eaten undercooked?
Metacercariae excyst in intestine and migrate to biliary ducts.
Where does Opisthorchis sinensis occur? Where are the reservoirs for this zoonotic infection?
SE Asia
Domestic animals.
What are the symtpoms of Opisthrochis sinensis? How may it be prevented? How can it be treated?
Depending on number of worms present, diarrhoea, biliary symtpoms and jaundice.
Praziquantel.
What is another name for fasciola hepatica? How is it contracted? Does it occur in Australia?
Sheep liver fluke.
Watercress from contaminated pasture.
Occassionally.
What is another name for Paragonimus westermani? Where is it found? Where do the adults live in the body?
Lung fluke.
Tropical countries.
In the lung.
How do the lung fluke eggs exit the body? What is the first intermediate host? What is the second intermediate host?
Coughed up and passed into water were they are swallowed by snail (1st).
Crab or crayfish.
What is another name for Fascilopsis buski? Where does is occur? How does infection occur?
Ginat intestinal fluke. SE Asia.
Through peeling water-chestnuts with teeth.
What do all blood borne parasites require?
Two hosts.
What is normally the first host of a blood borne parasite? What do they do when feeding? What do they acquire when feeding?
An invertebrate that feeds on blood. Inject the infective stage of the parasite.
Gain the gametocytes; immature form of the parasite.
What is the most important disease to man on a world-wide scale?
Malaria.
How many % of the world's population are at risk of acquiring malaria? How many cases are there a year?
How many deaths in children occur in Africa a year? What % of those who get P.falciparum malaria die?
40%.
100 million.
1-2 million.
1%.
What particular type of mosquite is required as a vector for Plasmodium falciparum?
Anopheles mosquitoes.
What are the four species of sporozoan parasite in the genus Plasmodium which may cause malaria?
P. vivax
P.ovale
P. falciparum
P.malariae
Which of the Plasmodium causes most malaria deaths?
P. falciparum
Where does the sexual phase of the Plasmodium life cycle occur? Where does the asexual phase of the Plasmodium life cycle occur?
In the mosquito.
In the human.
What stage of the Plasmdoium life cycle is injected into man? Which organ do they go to and what do they do when they get there?
Sporozoites.
The liver to undergo asexual reproduction (exo-erythrocytic schizogony)
Exceot for P. falxiarum what may occur to the parasites in the liver?
Survive for months or years giving bouts of fever.
What happens after exo-erythrocytic schizogony in the liver? What are the early stages called?
Schizonts enter the bloodstream and red blood cells were they feed on RBC as trophozoites.
Ring forms.
What occurs in the RBC during a Plasmodium infection? What occurs when the RBC ruptures?
24-72 hrs of growth then asexual division to give 12-16 merozoites. The merozoites invade other RBC.
What causes the recurrent fevers that characterise malaria?
Release of merozoites and related foreign protein and products of digestion.
After several cycles of Plasmodium maturation in the human what occurs due to invasion of new blood cells? What are these named? How can these develop further?
Formation of male and female cells.
Microgametocytes and macrogametocytes. If taken up by a mosquito.
What happens when gametocytes are taken up by the mosquito?
Change into gametes and fertilisation occurs in mosquito stomach lumen.
What does the zygote become in the stomach? Where does it go and to become what?
A motile ookinete.
Stomach wall and sporocyst.
What does division of the sporocyst cause?
Sporozoites.
Hlong is the incubation period for malaria? What are the early symptoms of malaria? What are some more major problems of a malaria infection?
8 days-3 weeks. Lethargy, headaches, chills and loss of appetite with a periodic fever.
Anaemia due to haemolysis of RBC, cereberal malaria and blackwater fever.
What is cerbeal anaemia and why does it pose a problem in humans? What is the sign of blackwater fever and why?
It is the sludging and stickiness of infected cells causing blockage of capillaries to brain.
Very dark blood due to massive red cell haemolysis.
How is immunity from malaria derived?
Repeated exposure in childhood, G6PD enzyme deficiency and Sickle Cell Trait.
What is the treatment for malaria? What do most drugs target?
Vary depending on exposure. Main treatments are Doxycycline and Artemesinin. Quinine is used for complications when no other drug is effective.
The dihydrofolate reductase that produces purines in DNA.
How may malaria be prevented?
1. Avoid being bitten by mosquitos: mosquite nets at night, screened windows, insect repellents, residual insecticides on bed ets or house walls, covering exposed skin.
2. Limit mosquito breeding sites: Anopheles like stagnant water, pools, polluted or saline water, water in tree-holes, tanks, pot-plants
3.Chemoprophylaxis (use of anti-malarial drugs to prevent development.)
Flagellates exist in four different forms, what are they? What is their morphological appearance? How many forms does each species pass through during course of its life-cycle? Which are the only forms found in humans?
Trypmastigote (flagellum and undulating membrane), promastigote (flagellum, no undulating membrane) epimastigta (flagellum and short undulating membrane), amastigota (rounded form without flagellum or undulating membrane, found in macrophaes).
2
Amastigote and trypomastigote.
What group do the flagellates come under?
Trypanosomes.
There are two main groups of Trypanosomes, what are they?
African and South American.
What are the two African Trypanosomiasis and what do they cause?
Trypanosoma brucei gambiense and T.b. rhodesiense cause Sleeping Sickness.
What is the form of the Trypansomiasis found in blood?
Elongated trypomastigote with anterior flagellum and undulating membrane.
How are Trypansosome brucie gambiense and T.B. rhodesiense transmitted? How do the trypanosomes multiply in humans? Where do they eventually get to and via what?
Via Glossina flies.
Longitidunal fission.
CNS via lymph.
What are the symptoms of a Trypanosoma brucei gambiense and Trypanosoa brucei rhodesiense infection? Which form is more virulent?
Ulcer at fly bite site, enlarged lymph nodes, fevers, muscle and joint pain. Progressive CNS symtpoms which can lead to coma and death. T.b rhodesiense.
Which of the African Trypanosomiasis has an animal reservoir?
T.b.rhodesiense.
How can the Trypansomiasis be controlled? What is the treatment?
Control of animal resrevoirs, control of Tsetse flies and chemoprophylaxis and chemotherapy. Aresnic derivatives such as Suramin and pentamidine.
What do the South American Trypanosomiasis cause? What is the parasite involved?
Chagas' disease. Trypanosoma cruzi.
How is Trypanosoma transmitted?
Reduviid bugs, or assasin bugs.
What form of T. cruzi is found in the blood? What form is found in tissues, particularly cardiac mucles?
Trypomastigote.
Amastigote.
When do the reduviid bugs bite and where on the human? What occurs after the bugs take a blood meal?
Bite on face at night.
They defecacte and this may infect bite wound allowing infective parasites to enter.
What are the sytpomes of Trypanosoma cruzi? What is it the most common cause of?
Nothing to severe eg. gut dilations most probably due to desturction of parasympathetic ganglia.
Heart disease in young to middle-aged people in large areas of South America.
Is Trypanosoma cruzi zoontoic? Where are the reduviid buds found and hence what is disease related to? How is it treated?
Yes.
Cracks in walls, therefore poor housing.
Nifurtamox.
What are the three most recognised and best studied Leishmanias? What type of sandflies are they transmitted by? What form are they in the sandfly? What form are they in the human?
L.donovani, L. braziliense and L.tropica.
Phlebotomus and Lutzomyia
Flagellated form.
Amastigote.
What does Leishmania donovani cause? What happens in this?
Kala Azar.
Reticulo-endothelial cells are invaded my amastigotes particularly in liver and spleen.
What are the symptoms of Leishmania donovani?
Fever, anaemia, gastrointestintal symptoms. Can caused eath within months or become chronic and cause death through liver failure years later.
What is Leishmania braziliense called and why? What characterises it? Who does it most involve?
Muco-cutaneous leishmanasis as it invovles mucus membranes.
Ulcer at the site of the bite spreading and eroding surrounding tissue.
Forest workes in S, and central America.
What does Leishmania tropica affect? What forms at the site of the fly bite? How long can healing take?
Only skin.
Nodule that can take a year to heal.
What are all three forms of Leishmania? How can they be diagnoses?
Zoonoses.
Amastigotes in stained aspirates or biopsies.
How may the Lieshmania be controlled and prevented? How can they me treated?
Detection and treatment of cases, vector control, reservoir control, vaccination against some forms of cutaneous leishmaniasis and limiting man-sandfly contact.
Sodium antimony gluconate.
How many hosts does Toxoplasma gondii have? Where does the sexual phase occur?
2
In cats.
What are the symptoms of Toxoplasma gondii? Why is Toxoplamsa gondii of particular importance?
Usually known but can present as long-drawn out illness like infectious monomucleosis with lehargy, chills, loss of appetite and fever.
Infection in an early pregnant woman can cross the placental barrier and affect the developing CNS of the foetus. Also important in AIDs patients.
What is the treatment for Toxoplamsa gondii?
Pyrimethamine and sulphadiazine and folinic acid.
How can Toxoplasma gondii be prevented?
Avoid close contact with cats and cleaning out litter boxes.
Where is the amoeba Naegleria fowleri found? How is is transferred and in what form? How is infection contracted?
Warm, stagnant water.
As a cyst by wind and dust.
When infected water is inhaled up the nose.
What does Naegleria fowleri cause and how? What is it commonly associated with in Australia? How is it treated?
Meningo-encephalitis, travels via olfactory never tract to meninges.
In-sufficiently cholrinated pools.
Amphotericin B.
What is Acanthamoeba related to? What can it cause?
Naegleria fowleri.
Keratitis by direct infection of eyes, especially in contact lense weares.
What does Pneumocystis carinii cause? What population is it a leading infection in, the % and % of deaths as a result?
Interstitial cell pneumonia.
AIDS patients, 60% and 25%.
How is Pneumocystis carinii treated?
Trimethoprim and sulphamethazone and co-trimoxazole.
Where does Trichomonas vaginalis commonly occur? How many anterior flagella does it have? How is it contracted and who is most at risk?
Female reproductive tract. Also in men but asymptomatic
4.
Sex and those who are sexually active.
What are the symptoms of Trichomonas vaginalis? How is it diagnosed? What is the treatment?
Vulvo-vaginitis with a frothy discharge.
Direct swab or via culture.
5-nitiroimidazole compounds.
What are the five Blood and Tissue-Inhabiting Nematodes?
Dracunculus medinensis, Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus and Loa Loa.
What is Dracunculus medinensis also known as? Where is it found?
Guinea worm.
Parts of Asia, Africa and S. America.
Where does the Dracunculus medinensis adult female live? How are larvae passed out? What then happens to larave?
Beneath the skin.
Anterior end of female extrudes as a blister, bursts and larvae pass out when immersed in water.
Ingested by small cyclops crustacean where undergo development and may be ingested by humans in drinking water.
How can Dracunculs medinensis be prevented?
Safe water supplies and treatment with various antihelminths.
What is special about the life cycle of the Nemtaodes in the family Filariidae? What four of the human Blood and Tissue Nematodes comes under this group? What animal worm is filarial?
Two-host-life-cycle.
Wucheria bancrofti and Brugia malayi, Onchocerca volvuls and Loa loa.
Dirofilaria immitis.
What is Drifofilaria immitis? Why are they important in man?
Heartworm of dogs in the tropics.
Occassionally humans bitten by an infected mosquito but larvae can not mature in man.
How are Wuchereria bancrofti and Brugia malayi transmitted? What is taken up by the female during a blood meal? When do they appear in the peripheral blood?
Via mosquitoes.
Microfiariae.
At night when mosquitoes bite.
After entering the female mosquito what happens to the Wuchereria bancrofti and Brugia malayi microfilariae?How long does this take and then what happens? Are they zoonotic?
Enter thorax of mosquito to undergo growth and development.
10 days, then reinjected with another blood meal.
W. bancrofti is not, B. malayi may have monkey reservoirs.
What are the syptoms of Wuchereria bancrofti and Brugia malayi? How is it diagnosed?
How is it treated?
May be nothing for years, recurring attacks of lymphadenitis and lymphangitis and chyluria (mily urine) and infections leading to gross swelling of legs and scrotum.
Blood smears.
Ethylcarbamazine. Surgey for gross elephantiasis.
Where does infection of Onchocerca volvulus occur? Where do the adult species live in humans? What happens to microfilariae?
Wide belt of sub-Saharan Africa and parts of Central and South America.
Nodules benetah skin, usually over bony prominences. Released into subcutaneous tissue and can be taken up by Simulium flies.
What happens to larave of Onchocerca vulvus once taken up by fly? What is the prevention and treatment for infection? What do they cause?
Progress to flight muscles and undergo growth and development before being reinjected in the human.
Destruction of fly larvae in rivers; avoiding fly bites, surgical excision of nodules and treatment of microfilarae by diethyl carbamazine, ivermectin or praziquantel.
Skin conditions and eye afflictions such as River Blindness.
Where does Loa loa occur? How is it transmitted? Where are the larvae? Where are the adults? What do they cause? What can the adults sometimes be seen to cross?
West Africa.
Chrysops tabanid flies.
Larvae are in the skin, adults migrate beneath it.
Migratory swellings.
Cornea.
What is the type of Trematode that infects man? What are the three species that infect man? Where are they found geographically, and where are there eggs found?
manSchistosomes.
Schistosoma haematobium-Africa and Middle East with eggs in urine, Schistosoma mansoni-Africa and Central/South America with eggs in faeces and Schistosoma japonicum-Parts of China, Japan, Phillipines with eggs in faeces.
Are the Schistosomes zoonotic? What type of parasites are the adults? Which vessels do S. haematobium live in? Where do S. mansoni and S. japonicum live?
Yes.
Intravascular.
Those around bladder, the other mesenteri vessels.
What happens once the spiked eggs of the Schistosomes are passed form human what do they form? How do they elude the hosts immune system?
Form miracidium larvae which infects a snail and undergoes enormous multiplication forming sporocytes releasing cercariae in the blood vessels.
Coat themselves in host substances.
What are the symptoms of the Schistosomes? How is it prevented? How is it treated?
Related to fibrosis surrounding eggs that are trapped in tissue. Diarrhoae, loss of weight, liver enlargement and failure, cystitis, renal failure and baldder cancer. enetration of skin by cerceria causes dermatities.
Safe disposal of faeces, avoding infected water, education, molluscicides.
Praziquantel.