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L31 & 32 - Parasitic Infections Protozoans 1) Discuss the…

- - - - Giardia Intestinalis
        Flagellate protozoan
        Mild intestinal disease
        Global Distribution
        Global
        
        Pathogenesis
        
        Signs & Symptoms
        
        Greasy stools that tend to float
        malabsorbtion of fat)
        
        Stomach or abdominal cramps + nausea
        
        Weight loss and dehydration
        possible
        
        Diarrhea + Gas or flatulence
        
        Diagnosis
        
        Microscopic observations of cysts/trophozoites in faeces
        
        Immunological tests
        
        PCR
        
        String test
        
        Trophozoite
        
        Cyst
        Ingestion of cysts (highly durable only 5 required for infection) =>
        mode of transmission
        
        ID50 is very small
        
        Can survive for weeks in cold water
        
        Morphology
        
        Smiley face with four flagella
        
        Prevention
        
        Hygeine (group)
        Avoid contaminated food/water
        
        Treatment
        
        Metronidazole
        
        Tinidazole
    - - Entamoeba histolytica
        
        Susceptible to paromomyci and metronidazole
    - - Toxoplasma gondii
        
        Infects ~30% of the world's populations - most successful parasite
        
        Pathogenesis
        
        Reproduces asexually in a cat
        
        5 mechanisms for transmission
        
        Infect any animal and any nucleated cell
        
        Infects Brain
        
        Difficult to treat past acute stage
        
        Transmissiom
        All of the animals we ingest are likely to have tissue cysts with Toxoplasma in them => transmission
        
        Symptoms
        Most remain Asymptomatic yet potential to
        
        Eye lesions:
        
        Myocarditis
        
        Lymphadenopathy with/without fever
        
        Congenital Toxoplasmosis
        
        Abortion
        
        Still birth
        
        Hydrocephaly, mental retardation and eye lesions
        
        Immunodeficient Toxoplasmosis
        
        Fatal, acute fulminating disease:
        
        3 more items...
        
        Detection
        
        Detection of antibody
        
        Detection of parasite
        
        Detection of parasite genetic materials by PCR:
        
        Prevention
        
        Adequate cooking of meat is essential
        
        Proper disposal of domestic cat waste
        
        Protecting children s play areas especially in the household environment from
        
        Treatment
        
        Pyrimethamine (Daraprim) and sulphadiazine
        
        Believed to be cause secondary behaviour affective disorders (schizorphrenia + bipolar) and cancer
        
        Potentially slows reaction time to kill host and spread infection
        MANIPULATION HYPOTHESIS
  - - - Trichomonas vaginalis
        Cannot survive outside of the body
        Common infection
- - - - P. vivax
      - P. malariae
        
        Africa and PNG
      - P. falciparum
        Located Primarily in AFRICA, PNG and SE Asia
        
        Sequesters
        
        Malignant Tertian (48hr)
        
        - FEBRILE SYMPTOMS
        
        Causes cerebral malaria and haemorrhaging - will kill you (extremely acute disease - by the time you are febrile you are too far dead)
        
        Mortality Facts
        
        Estimated 350-500 million cases each year
        
        990 000 people died of malaria in Africa 1995 - 1 person every 30 seconds
        
        Pathogenesis
        
        The P. falciparum parasite can infect RBC of any age, while other species are restricted to certain ages
        - Parasitaemia
        
        => Haemolytic Anaemia
        => RBCs also the express adherent proteins which stick in fine capillaries of deep tissues
        => this causes micro-haemorrhage - cerebral malaria kills you
        => Adherent RBCs do not filter through the spleen
        
        Pathogenesis cont.
        Febrile
        
        • Introduced into blood stream via mosquito bite, then undergo replication in liver
        
        1 more item...
        
        Diagnosis
        
        Microscopy
        
        Serology
        
        Rapid diagnostic testing
      - P. ovale
        
        Rare but widespread
    - - Treatment
        
        Artemisinin combination therapy
        => Artesun used in combination to prevent drug resistance and will effect different stages of the parasite
        
        => Proguanil
        => Pyrimethamine
        => Chloroquine
        
        Parasitic resistance to anti-malarials is common
- - - - Mucosal leishmaniasis (ML)
        Chronic
        Th1/Th2 response
        
        L. braziliensis
        
        Chronic - will keep prgressing until the tissue isconsumed
      - Visceral leishmaniasis (VL)
        Progressive - fatal
        Immune suppression
        
        L. donovani, infantum
        
        Post kala-azar dermal leishmaniasis
        
        Becomes systemic - generalised immunosuprresion
        
        Will die of haemorrhages proliferation of other pathogens
        
        95% die without tretment and > 90% cured with treatment
        
        Symptoms
        
        Fever, weight loss, muscle atrophy
        
        Hepatosplenomegaly
        
        Lymphadenopathy, pancytopenia
        
        - HIV co-infection (2-12% VL cases
        
        Diagnosis
        
        Clinical Diagnosis
        => Hard Palpable spleen, fever
        
        - Parasitological diagnosis
        => Parasites found in aspirates of bone marrow, lumph nodes or spleen
        Laboratory tests
        => DAT
        => PCR tests
        => ELISA tests
      - Cutaneous leishmaniasis (CL)
        Self curing
        Th1 response
        
        L. major, tropica
        
        Phenotypes
        
        Localise cutaneous leishmaniasis (LCL)
        
        Diffuse cutaneous leishmaniasis (DCL)
    - - Treatment
        
        Pentavalent antimonials (Amphoteric B + miltefosine)
        
        Most drugs are highly toxic
- - - - Itchy Bum
  - - - Pathology
        
        Helminths/worms can cause intestinal obstruction
        
        Migrating larvae travel to lungs (do not remain in the gut eggs/larvae travel through blood stream - lungs - trachae - oesophagus
        
        => Ascaris metabolites can cause sensitising phenomena urticaria, and asthma.
        => Migrate throughout body and may inadvertantly block narrow organs
        
        Symptoms
        
        85% Asymptomatic
        
        Inflammatio (Loefflers syndrome)
        
        Organ Infiltration and dysfunction
        
        Diagnosis
        
        Recovery of eggs from feces, or adult worms
      - Prevention
        
        Clean sanitary toilet and food preparation facilities
        
        Personal hygeine
        
        Treatment
        
        Mebebdazole, albendazole (except in pregnancy)
        
        Levamisole, thiabendazole, Pyrantel, piperazine
- - - - - S.haemotobium (bladder)
      - - S. japonicum (Intestinal)
      - S. mansoni,
    - - Prevention
        
        Prevent urine & faeces from contaminating fresh water.
        
        Improve irrigation + Molluscides
        
        Avoid skin contact with fresh water in endemic areas
        
        Mass population
        treatments with praziquantel
        
        Treatement
        
        Praziquantel and benzimidazole
    - - After penetrating skin Schistosomula enter blood vessels, migrate to hepatic portal system, mature & mate
        
        presence of eggs in the gut and bladder tissue and in organs around the body.
        => they have to migrate through tissues to the gut before they can spread, yet they can cause serious fibrosis whe the eggs fail to reach the gut
        
        Fibrosis => Granulomas (liver, brain epilepsy, lungs pulmonary hypertension, heart, spinal cord paraplegia, renal system)
      - Symptoms
        
        Hepatosplenomegaly,
        
        Portal HTN
        
        Ascites, anaemia,
        
        Malnutrition,
        
        Haemorrhage, death
        
        Diagnosis
        
        Stool: identify SM (lateral-spined), SJ (lateral knob) and SI (terminal spined) ova/
        
        Eggs in urine for SH
        
        Rectal snip – proctoscopy
        
        Serology – CFT/ELISA