parasite infections Flashcards

Question

describe ascariasis life cycle

Answer 1

nematode - roundworm feco-oral transmission adult worms live in the SI - female produce 240000 eggs a day passed in faeces fertile eggs embryonate and become infective after 18days to several weeks depending on env conditions after infective eggs are swallowed the larvae hatch, invade the intestinal mucosa and are carried by the portal then systemic circulation to the lungs (10-14 days) - penetrate the alveolar walls, ascend the bronchial tree to the throat and are swallowed upon reaching SI they develop into adult worms adult worm can live for 1-2 yrs

Answer 2

often asymptomatic - need a lot of parasites to see infection cause abdo pain/intestinal obstruction adults feed on the contents of the SI and this may cause problems in malnourished people - especially children migration of lavae may cause localised reaction in organs penetration of larvae from capillaries into the lungs can lead to Loeffler's pneumonia - pools of blood and dead epithelial cells clog air spaces in the lungs resulting bacterial infections can be fatal

Answer 3

stool examination ## Footnote albendazole and mebendazole

Answer 4

they stick to SI and cause bleeding = iron deficient anaemia can have cardiac complications GI and nutritional/metabolic symptoms minimal local skin manifestations - ground itch during penetration by the filariform larvae resp symptoms seen in pulmonary migration of the larvae

Answer 5

ancylostoma duodenale 1cm long - stuck by their buccal capsule to the villi of the SI go through the skin carried through bv to heart and hungs penetrate the pulmonary alveoli, ascend the bronchial tree to pharynx and are swallowed they reach the SI where they reside and mature into adults male and female make eggs which are expelled in faeces eggs have to transform into larvae to get into the skin diagnosis - stool examination treatment - albendazole and mebendazole

Answer 6

might be asymptomatic if a lot of worms - bloody diarrhoea and anaemia becasue of severe vitamin and iron loss leave open wounds which = inflammation of the intestinal wall might get rectal prolapse it is a hookworm

Answer 7

feco-oral eggs hatch in the SI - release larvae that mature in colon adult worms live in cecum and ascending colon adult worms are fixed here (because of the immune reaction caused, they are being sold as therapy against allergy and autoimmune conditions) diagnosis - stool examination treatment - albendazole and mebendazole

Answer 8

lymphatic obstruction, especially in legs, can brogress to elephantitis can occur in arm, breast, scrotum it is a filaria

Answer 9

transmitted by mosquito blood found in peripheral blood at night, in day they are in deep veins diagnosed by blood smear in night or ag detection with an immunochromatic test (card) or ELISA, RAPID test treatment - albendazole and ivermectin

Answer 10

transmitted by fly migrate through the subcutaneous tissue, may cross the front of the eye under the conjunctiva microfilariae develop from the larvae in female and circulate in blood where picked up by fly and in the gut of the fly the microfilae enter the fat bodies and mature into infective 3rd stage larvae infect new host when fly takes blood meal

Answer 11

* T. solium and T. asiatica – pig is intermediate host * T. saginata – beef is intermediate host humans are the only definitive hosts

Answer 12

most people asymptomatic Patients with T. saginata taeniasis often experience more symptoms (size of the worm up to 10m) than those with T. solium or T. asiatica (~3 m). Tapeworms can cause digestive problems including abdominal pain, loss of appetite, weight loss, and upset stomach. The most visible sign of taeniasis is the active passing of tapeworm segments

Answer 13

diagnosis - segment in stool/eggs in stool treatment - praziquantel ingested in poorly cooked cysts in meat can be infected a long time after eggs are in the faeces - eggs can survive for days to months in the environment

Answer 14

commonest cause of acquired epilepsy worldwide

Answer 15

within days rash and possibly itchy skin Within 1-2 months; fever, chills, cough, and muscle aches but most people have no symptoms at this early phase of infection When adult worms are present, the eggs that are produced usually travel to the intestine, liver or bladder, causing inflammation or scarring. children who are suseptible - anaemia, malnutrition and learning difficulties after yrs of infection - can damage the liver, intestines, lungs and bladder

Answer 16

diagnosis - stool/urine samples treatment - praziquantel - treat people even if they are asymptomatic in order to reduce transmission problem is praziquantel can cause the liver to bleed = death S. mansoni, haematobium and japonicum eggs eliminated in water by faeces/urine - hatcha nd release miricidia - penetrate the snail - release carcariae - penetrate the skin = migrate through tissues - adult worms reside in venules - in the lumen of the intestine (S. mansoni and S. japonicum) and of the bladder and ureters (S. haematobium). kills the snails ie the intermediate host therefore the worm cannot infect the skin = no infection

Answer 17

extoparasite - paraite on your skin transfer between people cause itchy burrow on skin diagnosis - rash and burrows treatment - scabicides

Answer 18

* Pediculus humanus capitis (head louse), * Pediculus humanus corporis (body louse, clothes louse), and * Pthirus pubis ("crab" louse, pubic louse) transmitted between people have 3 stages - eggs, nymphs and adults diagnosis - finding live nypmh or adult lice on scalp/hair of the person

Answer 19

endoderm - protazoa - flagellate

Answer 20

transmitted from flies taken up by the phagocytic cells 1st - neutrophils then macrophages/monocytes this can kill/promote the survival of the parasites life cycle continue when sandfly bite infected host then bite another person

Answer 21

promastigote - this is the form in the sandfly, they move in the direction of the flagellum and can be cultured amastigote - form in human or other vertebrate host's cells - have resorbed their flagellum so not motile

Answer 22

the vector for leishmaniasis found mainly in mainly in the warm parts of the world, including southern Europe, Asia, Africa, Australia, Central and South America - because of climate change - spreading northwards from greece and Turkey - occurs in southern france and is spreading through italy, some in isle of white small so go through mosquitoe net, hairy, hop around before settling to bite, silent female feed on blood to provide nutrition for eggs

Answer 23

visceral leishmaniasis (Kala azar) cutaneous leishmaniasis * cutaneous * diffuse cutaneous * mucocutaneous

Answer 24

most severe form of leishmaniasis - fatal if untreated characterised by irregular fever, weight loss, swelling of liver and spleen, anaemia suppressed immune system also can get - lymph nodes, loss of appetite, cough, hepatomegaly, oedema, diarrhoea, vomiting and jaundice also known as kala azar (black fever) - cause darkening of skin a lot of asymptomatic cases - 30-100 subclinical infections for every overt VL case species - L donovani vactors P martini, P celiae, P orientalis

Answer 25

malnutrition, immunosuppresive drugs, HIV co-infections usually ypung men have it - come to an area where there is visceral leishmaniasis endemic and havent been exposed

Answer 26

look at spleen and liver size and the parasite load in bone marrow and spleen - how many in the macrophages diagnosis is aspiration of the spleen and looking at the parasites but this is a complicated technique clinical diagnosis based on definition - no rapid test so people think that it is malaria - "a person who presents with fever of more than two weeks and enlarged spleen (splenomegaly) and/or enlarged lymph node (lymphadenopathy) or either of weight loss, anaemia or leucopenia while living in a known VL endemic area or having travelled to an endemic area”. detecting Ag is a problem because it cross reacts with malaria and HIV, also could have had previous infection and might have malaria now not this lab investigations - visualisation of the amastigote form of the parasite by microscopic examination of aspirates from lymph nodes, bone marrow or spleen - need specialist probe Ag detection - Direct agglutination test (DAT) and rK39 chromatographic test people have low WBC, platelet count and are anaemic

Answer 27

in Africa - sodium stibogluconate and paromomycin for 17days - have a lot of SE - often the reason for the death, people are too ill with renal and liver problems that are made worse in india - 1 shot of AmBisome, works well because there is a lot of awareness of the disease so people present early

Answer 28

frequent in sudan and india - in 55% of pts in sudan, 5-10% in india occurs during or after treatment, after sub-clinical infection lesions start on face usuallly around the mouth - become nodular can spread to trunk and limbs difficult to treat because there is a lot of parasite in the lesion - this is a problem for transmission

Answer 29

skin lesions on exposed body parts - often self healing can create serious disability and scars give immunity to reinfection L tropica - crusted ulcer, L major - multiple crusted lesions large irregular ulcer, surrounded by papular and crusted lesions which all contain parasites, crust can fall off - can be wet before you get ulcer leaves scars

Answer 30

disseminated lesions, resembles leprosy - multiple nondular non-ulcerating lesions that are full of parasites = difficult to treat no spontaneous healing frequent relapses L aethiopica stigma because look like leprosy - people think leprosy is transmitted in childbirth so women with it are oestrasised from society - so take baby girls and expose bottom so that they can develop immunity and not develop it on their face treatment makes it a bit better

Answer 31

Mucocutaneous (L. braziliensis/panamensis)/mucosal (L. infantum, major, tropica, aethiopica) disfiguring and destroys mucus membranes around mouth and nose and eyes

Answer 32

in ethiopia - mainly in the highlands annual burden - 20000 to 30000 cases - rough estimation

Answer 33

p longipes p pedifer p sergenti p saevus p duboscqi

Answer 34

clinical diagnosis parasitological diagnosis that involves microscopy/culture - fine needles aspiration, dermal scraping, biopsy leishman skin test serology PCR

Answer 35

*  Systemic treatment with Sodium Stibogluconate (SSG) or Glucantime *  Intra-lesion administration of SSG cryotherapy miltefosine (compassionate)

Answer 36

they causes each other to multiply - problem for treatment in europe 70% cases of VL are associated with HIV ART reduces incidence of VL, relapse rates, prolongues the interval between prolapse rates, improved survival in brazil - there is high parasite load, parasite dissemination to unusual sites, lower cure rates, greater suseptibility to drug toxicity, increased drug resistance, higher rates of death, higehr rates of relapse ethiopia carries highest burden of HIV-VL co-infection = high rates of relapse and high rates of mortality • HIV infection can lead to reactivation of latent Leishmania infection or to symptomatic VL at initial infection - after 2nd relapse difficult to control viral load so die  100-1000 x greater risk for HIV+ individuals to develop the disease as compared to HIV- individuals VL increases the onset of AIDS - increased HIV replication and cumulative immunosuppression

Answer 37

mainly in young men there are areas where there is endemic VL - people come and farm who havent been exposed the areas act like little cities so have a lot of HIV, then these people contract VL