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by Daniela W.

What are Apicomplexa?

unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure

• unicellular and spore-forming

Are Apicomplexa unicellular or multicellular?

Groups of Apicomplexa

coccidia
gregarines
piroplasms
haemogregarines
plasmodia

What is an Apicoplast?

relic, nonphotosynthetic plastid found in all protozoan parasites belonging to the phylum Apicomplexa

To what group does Toxoplasma gondii tachyzoite belong?

Where does Toxoplasma gondii appear geographically?

high prevalence in industrialized countries

What animals are infected by Toxoplasma gondii?

infecting warm-blooded animals from birds to humans

What animals are the definite hosts by Toxoplasma gondii?

cat, wild cat, lynx, lions…

Toxoplasma gondii – life cycle

What are the different ways of transmitting Toxoplasma gondii?

Foodborne transmission
Animal-to-human (zoonotic) transmission
Mother-to-child (congenital) transmission
(Rare instances of transmission)
- Organ transplant recipients, blood transfusion, accidental inoculatio

What is congenital transmission?

Mother-to-child transmission

What kind of cells does Toxoplasma gondii infect?

parasites invade subepithelial cells

What are the thee assexual forms of Toxoplasma gondii?

sporozoites or bradyzoites infect humans
parasites invade subepithelial cells + asexual multiplication
tachyzoites are disseminated via blood and can penetrate barriers (placenta, brain, tissues)
multiplication of tachyzoites slows down (immune pressure)
bradyzoites develop (slowly replicating cells)
parasitophorus wall remodels into a cyst wall=> brain cys

How many humans are infected globally by Toxoplasma gondii?

15-85%

How many humans are infected by Toxoplasma gondii in Germany?

30-60%

What happens at an infection of an immunocompetent host?

self-limiting infection

What happens at an infection of an immunosuppresing host (e.g. AIDS)?

tachyzoites can be reactivated and cause severe local inflammation (encephalitis 1of 5 AIDS patients)

T. gondii removes rodents’ innate fear of cats

T. gondii-induced behavioural changes in rodents are an example of adaptive manipulation to …

enhance transmission to cats

Def. Adaptive Manipulation

parasite-induced changes in host behaviour that benefit the parasite, often through enhanced transmission to the next host in the life cycle of the parasite

1. The parasite itself does something specific and direct to the host, in order to alter behaviour to its own benefit.

2. The host changes its own behaviour in order to eliminate or minimise the effect of infection.

3. The change in host behaviour is the coincidental result of pathology or immune response.

when is an unborn child not at risk for toxoplasmosis?

???

five human pathogenic species from the Genus Plasmodium

P. vivax

P. falciparum

P. ovale

P. malariae

P. knowlesi (zoonotic, macaque monkeys)

Is the malaria species P. vivax

Apicomplexa life cycles - in general

What are the blood stages of a Plasmodium ?

How can you test for malaria?

RDT: rapid diagnostic test

immunocromatographic assay for the search of plasmodia antigens in blood samples: P. falciparum (Pf), P. malariae (Pm), P. vivax (Pv), and P. ovale (Po)

• currently available RDTs are not able to detect P. knowlesi

Plasmodium development in the mosquito midgut

What makes a vector a good vector?

Vector density
Vector biting rate
Vector competence
Vector daily survival probability
Pathogen incubation period
Vector lifetime survival

How can researchers use gene drives in mosquitoes to control the vector?

Option 1: sterility-inducing genes (suppression)

Option 2: competence-reducing factors (modification)

Definition Gene Drive

A genetic element that introduces a bias in the relative chance of inheritance between distinct versions of a set of genes, enabling one to spread rapidly in a population at the expense of others (even if it is disadvantageous to the organism).