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