MICROPARA CHAPTER 6 (reviewer!)

PROTOZOA Chapter 6

BLOOD AND TISSUE PARASITES MALARIA

TRYPANOSOMATIDS Haemoflagellates  – obtain haematin from blood Kintoplast – part of  mitochondria rich in DNA maxicirles – mt enzymes  minicircles – RNA editing 

American Trypanosomiasis (Chagas Disease)

Plasmodium Falciparum – most severe  Vivax – majority  ovale  malariae 

Through bite of mosquitos genus Anopheles  – genus Anopheles

Fever – most common vivax & ovale  –24hrs  malariae – 72hrs  falciparum – 48 hrs  Chills - frequent Headache Myalgia Nausea Vomiting - occassional Diarrhoea Abdominal pain Anaemia Cerebral malaria - serious Severe anaemia

Rupture of mature schizonts → fibrile response Sporozoites (mosquito) → liver (3o min) → spherical, multinucleate schizont (2000-40000 uninucleate merozoites)

Erythrocytic schizogony  – 5-21 days vivax & ovale  – 1-2 yrs  clinical illnass stage  Hypnozoites  – “quiescent parasites”

Tryponosoma cruzi – Chagas Disease  brucei – sleeping sickness  Leishmania tropica  major  mexicana amazonensis braziliensis – cutaneous and mucocutaneous donovani - Kala-azar (visceral  leishmania) Triatomine bugs Triatoma Rhodnius Panstrongylus Mucosa or abrasion in the skin

Localized infection → Trypomastigote  – blood parasitaemia → colonization of  Amastigote – Tissue internal organs and tissues Epimastigote  – intestine Infection – small tumour (chagoma) Fever Oedema Myocarditis With/w/out heart enlargement Meningoencephalitis – children Cardiopatyhy  –chronic

Trypomastigote (insect) → epimastigote → active reproduction (8-10 days flushed with faeces) → amastigote

PROTOZOA Chapter 6 African Trypanosomiasis (Sleeping sickness)

Cutaneous and mucocutaneous leishmanias

T. brucei  Rhodosiense  gambiense 

Local infection → general circulation (lymphatics)

Braziliensis – oral/nasal mucosal 

Bite of infected sand flies

Others - dessimenated 

Europe + Africa – rodents

Latin America and Mediterranean area

India – no other vector Latin America – dogs (lutzomyia longipalpis)

Visceral Leishmaniasis (Kala-azar)

TOXOPLASMA GONDII

Coccidia (group of protozoa) → Cryptosporidium (genus)

Cat Consumption of uncooked infected meat Faecal water contamination

Fever - recurrent Headache Lymphadenopathy Splenomegaly Meningoencephalitis Coma Death Papule (2-3 weeks after bite) → ulcerate → secondary infections oral  nasopharyngeal  symptoms – caused by uptake of parasites by local macrophages Nodile → rarely uncerates → disappears in few weeks Undulating fever Malaise Diarrhoea Organ enlargement Anaemia Invade internal organs – serious (liver, spleen, bone marrow, lymph nodes) Asymptomatic Congenital disease – children → during pregnancy Most common symptom (postnatal) Fever Malaise Fatigue Muscle pains Sore throat Headache

Multipiles in cerebrospinal fluid Infection – due to inflmammatory changes induced with an induced autoimmune demylenation of nerve cells Secondary infection (pneumonia) – immunosuppressive action of parasite’s membrane Amastigote – human Promastigote – sand fly

Enlargement – marked cellular alteration such as hyperplasia Macrophages replace tissue in the bone marrow With advanced disease → prone to superinfection (bacteria)

Cat – definitive host Human – intermediate host Cat 3 infectious stages Rapidly multiplying forms, tachyzoites Dotmant bradyzoites in infected tissue (cyst) Oocysts in shed in faeces (cyst) → intestine → release of bradyzoites → intestine → asexual generation → sexual → invade surface of epithelia → penetrate lamina

PROTOZOA Chapter 6

Fatal encephalitis – immunosuppressed headache disorientation drowsiness hemiparesis reflex changes convulsions Prenatal – brain + retina impaired vision – mild Classic tetrad – severe Retinochoroiditis Hydrocephalus – least common Convulsions Intracerebral calcification

propria begin to multiply as tachyzoites (troprohzoites) → other tissues (blood and lymph) → dadami ng dadami!!!! → resting stage (bradyzoites isolated in tissue cysts - brain, liver, muscles) Humans – no sexual stage Tissue cyst (meat/faeces) → epithelia → multiply → spread (lymph and blood) → lymph nodes → distant organs → focal areas of necrosis (many organs) Eye, heart, adrenal → vital + vulnerable organs Immunosupressed – reactivation. Predominant lesion (encephalitis in patients) – necrosis → multiple abscesses

PROTOZOA Chapter 6

INTESTINAL PARASITES  – all examples are faecal-oral route Faecal –oral route Contaminated water Zoonotic transfer Sexual activity (part, homosexual men)

GIARDIA LAMBLIA (syn. Intestinalis duodenalis) Giardiasis – severe diarrhoeal disease UK, USA, Eastern Europe

ENTAMOEBA HYSTOLYTICA Amoebic dysentery (developing countries)

CRYPTOSPORIDIUM PARVUM Crytpspordiosis – immunocompromised patients only – 3 weeks lang!

E. hystolytica - asymptomatic / minimal symptomatology E. dispar  – limited pathogenicity No symptoms

Group I - C. hominis – infect human only Group II – wider range of host

Faecal-oral route Reflects lack of adequate sanitary system

Oocyst in contaminated water/food Cattle – most impt. reservoir

Diarrheoa / loose Foul smelling stool Steatorrhoea (fatty diarrhoea) Malaise Abdominal cramps Excessive flatulence Fatigue Weight loss Immune deficient / protein calorie malnutrition people Interference with the absorbtion of fat Fat-soluble vitamins Retarded growth Weight loss Coeliac disease-like syndrome Mucosal erosion – diarrhoea Peritonitis – severe Liver infection (abscesses/enargement) – extraintestinal amoebiasis Jaundice – blockage of bile Pleural, pulmonary, pericardial infection- spread from liver Viscera, brain – uncommon Hepatic, lung infection Often asymptomatic Watery diarrhoea Stomach cramps Nausea Vomiting Fever Sever gastroenteritis pneuomonia

2 life cycle forms: Vegetative binucleate trophozoite Transmissible quadranucleate cyst Trophozoite – 4 pairs of flagella + adhesive disc Division – longitudinal fission 1 cyst – infective dose! 10 – 100 – more likely. First cyst in faeces – after 7-10 days!

Trophozoite – actively motile Cyst – spherical Thins transparent wall 4 nuclei Mature cyst → gut → simple fission → 4 amoebic cells → secondary division → each cyts = 8 trophozoites

Oval oocyst Sporozoite 100 – min. infective dose Oocyst → environmental stimuli (typical intestinal condition) → epithelial cells → several cyles → 2 forms of oocyst Soft-walled – reinitiates infection Hard-walled – exoelled in faeces