Specialisation Flashcards
(21 cards)
Types of parasite adaptations
Morphological and biological
Morphological adaptations
- Development of attachment organs
- Reduction of locomotive organs
- Reduction/absence of non-useful organs
- Biotope adaptations
Development of attachment organs in enteroparasites?
Suckers, hooks, teeth
Development of attachment organs in ectoparasites
Legs with prehensile elements
Reduction of locomotive organs
- loss of wings in Melophagus (Diptera)
- no movement in Leishmania’s intracellular stages
Reduction/absence of non-useful organs
Cestoda have no digestive tract
Biotope adaptations
Enteroparasites are elongated
Parasites in cavities are often spherical
Biological adaptations
- Reproductive adaptations
- Space-temporal adaptations to their vital cycle
- Physic-chemical adaptations
- Parasitic interactions
- Manipulation of the host’s behaviour
- Evasion of the host’s immune system
Reproductive adaptations
Spermatozoa reserves (spermatheca) Avoiding fertilisation (parthenogenesis) Hermaphroditism Increase in nr of genital organs Increase of prolificity/Resistance of eggs Multiplication of some asexual stages
Space-temporal adaptations
Seasonal convergence
Timely convergence
Spacial convergence
Temporal arrested development
Seasonal convergence
The parasite hatches around the same time as new hosts
Timely convergence
The parasite moves during certain time period such as during the night
Spatial convergence
Taenia saginata and Taenia solium in human (humans share space with bovines and swines)
Physiochemical adaptations
Enteroparasites are resistive to digestive enzymes
Some parasites are resistant to environments with poor oxygen
Parasitic interactions
Convergent evolution (similar anticoagulants)
Polyparasitism
Hyperparasitism (parasite inside a parasite)
Evasion of the host’s immune system
- Blocking the immune system of the host
- reducing the immunogenic character of their antigens
- Manipulation of the parasitic antigens
- Manipulation of the immune response of the host
- Resistance to the immune system of the host
Blocking the immune system of the host
- bigger size
- changing places
- variating antigens
Reducing the immunogenic character of their antigens
- location in areas less accessible to macrophages (brain)
- smaller doses (>smaller response)
- mimetism
- adsorption of the hosts proteins
Manipulation of the parasitic antigens
- protein surface variability
- antigenic variability between different stages
Manipulation of the immune response of the host
-some parasites secrete molecules similar to cytokines
Resistance to the immune system of the host
Resistance of the intracellular stages of leishmania to phagolysosome’s enzymes and oxidative mechanisms
fasciola’s ability to lyse antibodies by their protease secretion
