Introduction Flashcards
Definition of parasitology
It is the science of studying parasites that affect the man
Definition of commensalism
One organisim benefits from the other but does not harm it
Mutualism definition
Shared benefits are present
Parasitism
One organism is benefited and the other is harmed
Vector:
An arthropod that carries parasite to its host
Host:
The organism that harbor the parasite and is usually larger than it
Types of hosts:
Definitive host Intermediate host Reservoir host Accedental host Complete host
Definitive host:
In which final or sexullay mature stages of the parasite develop
Intermediate host:
In which asexual or immature stages of the parasite develop
Reservoir host:
Animal that harbor the same species of parasite like man and considered a sorce of infection to him
Accidental host
An organism that is not normally infected with the parasite but once infected, life cycle of the parasite continues
Complete host
When one host acts as both definitive and intermideate host
Diseases of animals that are transmitted to man are called:
ZOONOTIC DISEASES
Symbiosis
When a pair of dissimilar organisms live together in an intimate association
The chain of infection:
The causative organism –>The reservoir host –> Portal of exit –>Mode of infection
^ I
I I
I V
The suceptible host
Ectoparasite
Live of the surface of the host body
Endoparasite
Live within the body of the host
Can be intracellular or extracellular
Obligate parasite
Completely depends on the host
Facultative parasite
Capable of living both freely and as a parasite
Accidental parasite
Parasite found in host other than its normal one
Opportunistic parasite
Occus in immunocompromised individuals and causes nothing to mild symptoms in immunocompetent patients
Direct effects of parasite on the host
- Impairment of nourishment
- Mechanical or traumatic effect
- Toxic effect
- Secondary infection
Indirect effects of parasite on the host
- Generalized (Fever, malaise, weakness, Anaemia, eosinophilia, leucocytosis, leucopenia, Allergic reactions.)
- Localized (Gastrointestinal (colic, dyspepsia, diarrhoea …)
Neurological (headache,convulsion,paralysis)
Respiratory (cough,dyspnea,wheezes)
Cutaneous (itching,rashes,ulceration))
Parasites survive mostly in ……… and ………….. regions
tropical ……. subtropical