1.20.2.09 - Introduction to CAR Parasitology
insects, protozoa and heminthes (worms)
definitions
parasitism
mutualism
commensalism
only one organism benefits from this association without causing any harm to the second organism e.g. fish which live within the tentacles of sea anemone (fish obtains a degree of protection)
organisms of different species both benefit from the interaction e.g., honey-bee and flowering plant
only one organism benefits from the interaction but this to the detriment of the other
types of parasites
obligate
endo-parasite
facultative
ecto-parasite
May survive in the absence of the host e.g., opportunistic
At some or all stages of life cycle cannot survive in the absence of the host
Lives internally inside the host, e.g., worms, protozoa
Lives in/on the outer body surfaces of the host e.g., fleas, lice, ticks, mites
types of hosts
non-permissive host
reservoir host
permissive host
paratenic host
intermediate host
definintive (final)
The host in which parasite sexual reproduction occurs
The host in which parasite asexual reproduction occurs
Not usually used by parasite but still favours life cycle completion e.g., liver fluke (Fasciola hepatica) infection in humans
Host in which the parasite cannot complete the life cycle. e.g., Toxocara infection in humans
Temporary host used in the absence of natural host e.g., human trypanosomes reservoir in cattle and antelope
Host the parasite without any further development e.g., rodent in cat or dog lungworms
vectors
mechanical vector
biological vector
A vector which mechanically spreads parasite and is not utilised in the parasite life cycle e.g., Tabanid flies (horse fly, deer fly)
A vector needed by the parasite to complete part of its life cycle e.g., Glossina pallipides transmits T. brucei brucei causing trypanosomiasis (nagana disease) in cattle
methods of spread of parasites
direct animal to animal contact (mites)
trans-placental
skin inncoulation by isect bite (vector-borne)
sexual intercourse
skin penetration of infective stage
inhalation
ingestion of infective stage
why do we study parasitology
parasitic disease are common causes of mortality and morbidity in animals
emergence and spread of drug resistant parasites is a growing concern
75% of top killers of people are parasiric dieases - malaria, trypanosomse, schistosomes and many more
circle of infection (lifecycle)
parasite
susceptible host
portal of entry
mode of transmission
reservoir
portal of exit
parasite
types of life cycles
direct lifecycle
indirect lifecycle
parasitic stages develop in/on 1 host
intermediate host is needed for the development of some stages of the parasite
bovine lungworm
canine heartworm develops on mosquitos and then is transmitted to dogs
zoonosis
animal to human transmission
information you need to know about the lifecycle
what is the infective stage?
what is the route of infection?
who serves as an intermediate host, if any?
who serves as the definitive host?
type of life cycle
understanding life cycles
determine therapeutic window
manage disease properly
protect other animals for cors-infection
protect the public form zoonotic infections
informs pathology and diagnosis
parasitic control
treatment and intervention
hygiene and nutrition
avoiding risky behaviour
disrupt transmission
the ONLY vaccine preventable parasite
every single part of the cardio-respiratory tract can be places for parasites to hide
trachea
lungs
nasal cavity
oesophagus
heart
arteries