Parasitology 1 Flashcards
What is the equation for control and what does each mean
C = M + E + T
Management - hygiene, fences
Epidemiology - using vector, intermediate hosts, temperature and environmental conditions
Treatment - will have to use drugs but resistance issue
What are the 4 main elements of the parasite lifecycle
1) infection - host, feed, lifecycle
2) location - where, damage
3) transmission - how leaves the host, size
4) treatment and control - hos prevent infection, drugs, block transmission
what is the paratenic host
parasite acting as a passenger, just hold parasite within and gets eaten
No development no sexual reproduction just transport
List 3 examples of how parasites change host behavior
1) Liver fluke - dicrocelium
- Manipulates host(snail) to produce slim that ants love
- Forces ant to leave the colony and climb long stalks of grass and easy to eat areas for grazing definitive hosts
2) Leucohloridium
- Infect snail gets into eye stalk, flashing, enlarged hoping a bird will come and eat it
3) Nematomorphs
Larvae need water make host (arthropods) commit suicide in water
What defines crustaceans, insects, arachnids
crustaceans - >5 pairs legs
Insects - 3 pairs legs
Arachnids - 4 pairs (adult), 3 pairs (larvae)
What are the 2 important features of the arthropods gastrointestinal system
1) Malpighian tubes - series of tubules that connect to central gut system, how arthropods breathe
2) Salivary glands - acts as a vector for arthropods to transmit other parasitic organisms
List 3 features of arthropods
1) Cuticle: chitinous exoskeleton, impervious to many chemicals
- Many chemicals designed to fight this feature
2) Muscles: internal, attached to exoskeleton
3) Open circulatory system, blood free in haemocoel
what is the brain of the arthropods
oesophageal ganglia
- ganglion in each segment
arthropods respiratory system: trachea system for terrestrial forms what structures involved and what used for
- Valves scattered along the body called sphericles and can open and close depending on the environment and air dispered along the body
- Important for identificated, counting spheracular plates in the sphericles can determine between species
List the 4 types of parasitism, describe and give a general example
1) Obligate parasites - must have a host (flea)
2) Facultative parasites - can survive without host (flies)
3) Permanent parasites - on host all the time (lice)
4) Intermittent parasites - visit host periodically (mosquito)
what are the 3 general chemical control methods used for athropods
1) repellents (don’t kill such as DEET)
2) chemicals acting on the nervous system
3) growth regulators
What are the 8 classes of chemicals that act on the nervous system and general mechanism and environmental impact
1) chlorinated hydrocarbons
- banned as biomagnify
2) organophosphates - inhibits acetlycholine esterase, becomes paralysed, non-cumlative, breaks down
3) carbamates - similar mode as organophosphates, persistes 4-6 weeks
toxic to vertebrates
4) formamidines - highly toxic to horses and chiuzwazars
5) Pyrethroids - synthetic persist 7-14 days, act on sodium channels - paralysis, toxic to vertebrates
6) macrocyclic lactones - very common and potent, - Act on glutamate-gated chloride channels which leads to flaccid paralysis
7) neo-nictinoids & others - non-toxic, banned in some countries due to association with bee collapse syndrome
fipronil - frontline, imidacloprid - advantage
8) Benzimidazole
what are the major groups of macrocyclic lactones and examples within
1) Avermectins: examples - Ivermectin, Abamectin, Selamectin
2) Milbemycins: examples - Moxidectin
List the 8 classes of chemicals that act on the nervous system
i. Chlorinated hydrocarbons
ii. Organophosphates
iii. Carbamates
iv. Formamidines
v. Pyrethroids
vi. Macrocyclic lactones
vii. Neo-nicotinoids & others
viii. Benzimidazole
Growth regulators how used and mechanism
- Combined in treatment program with one of the chemicals used on the nervous system
- Analogues of insect growth hormones
○ Interfere with growth/moulting/egg laying - Lower chances of insecticide resistance occurring with combination as it will prevent the survivors from nervous system destroying chemicals from reproducing
Pentastomida mouth structurs and hosts
- 4 hooks and mouth create the 5 appendages - pentastomes
- Parasitic in respiratory system of birds, mammals and reptiles
- 2 hooks on either side of the mouth
Linguatula serrata what is it, where found, zoonotic?, clincial signs, diagnosis and treatment
CRUSTACEANS - Pentastomida
- Tongue worm of the dog
- Not a worm or in the oral cavity
- Found in nasal cavity of domestic and wild dogs
Zoonotic
Clinical signs : nasal discharge, irritation
Diagnosis : find eggs in faeces - millions
Treatment : Ivermectin
Linguatula serrata what type of lifecycle, hosts and stages
Indirect lifecycle
Intermediate host - rabbits, humans, sheep
Definitive host - dog or human
1) Faecal oral route - oral ingestion of the egg with embryo within
2) Several larval stages L 8 - L 9 the instart stages
3) Larvae penetrate the intestinal wall and start moving into tissues and start development - many stages within the intermediate host
4) Definitive host needs to eat intermediate host to become infected
5) After ingestion lodge in upper digestive tract and crawl into nasal cavity
Armillifer armillatus what is host species, zoonoic? lifecycle
Important in snakes
- Parasite of reptiles
- Small mammal or arthopods as intermediate host
- Zoonotic but rare
Definitive host has to ingest the intermediate host in order for sexual reproduction
Describe the Antennae and wing characteristics of Nematocera, Brachycera and Cyclorrhapha
Antennae Nematocera - segmented, thin Brachycera - thicker still segmented Cyclorrhapha - branching arista of the end point Wings Nematocera - longer thinner Brachycera - thicker more robust Cyclorrhapha - similar to brachycera
Nematocera features:
size, antennae, larvae, feed, type of parasite, host
- small flies (up to 3mm) - elongated
- antennae long and slender
- larvae and /or pupae are AQUATIC - need high moisture content such as cow patties
- females parasitic - need a blood meal
- intermittent parasites - need a host 100% to complete lifecycle but happens randomly, not permanent parasite
- often not host specific can bite anything
List the 3 effects Nematocera have on the host
1) irritation due to bites
2) blood loss
3) VERY GOOD VECTORS
1. viruses - blutongue
2. bacteria - anthrax
3. protozoa - malaria
4. nematodes - dirofilaria (heartworm)
Culicoides features:
identification, lifecycle, feed, effects on host
Identification : spotted wings
Life cycle : larvae develop in water, mud, sand or dung
- males/females feed on nectar, females also need a bloodmeal - can feed heavily
- Painful bites - ciliserae that cut into the host
What are the 3 main groups of species for Cullicoides and where breed and host
- “maritime species” C. immaculatus, C. marmoratus breed in saline waters
- “native species” C. marksi breed in fresh water, feed on marsupials and stock
- “introduced species” C. brevitarsis, C. wadai breed in cattle dung - not native to Australia, efficient vectors
List the 2 maritime species where breed, when feed, host and zoonotic?
C. immaculatus, C. marmoratus
- breed in mangroves
- crepuscular (feed at twilight)
- not host specific
- human nuisance
List the native species where breed, what season abundant, when feed and on what and what is important
Culicoides marksi
- breed in pools of water
- abundant in wet season in northern Australia
- crepuscular - twilight
- feeds on legs and belly of cattle
important - transmits the nematode Onchocerca gibsoni
List the 2 introduced species, when feed, where breed and bite, why is it significance
- Crepuscular - feed at twilight
- breed in cattle dung* - moist
- bite on dorsal midline
Significance : - cause “Queensland itch” in horses
○ Lesions around tail, rump, back, poll, ears
○ Hypersensitivity to bites
○ Use repellents and stable horses just before twilight, clean up dung - transmits bluetongue - horrible virus that sheep farmers don’t want, wipe out sheep
List differences between Culicoides brevitarsis
and Culicoides wadai in terms of distrubution and vector
Culicoides brevitarsis - wide distribution - inefficient vector with bluetongue - Worse with the Queensland itch Culicoides wadai - limited distribution - effective vector with bluetongue
Simuliidae features:
- have a hump back
- slicing cliserae
- life cycle aquatic - rivers
- larvae are carnivorous - lots of damage
- can cause swarms during floods
A.pestilens and S. damnosum significance and effects on host
black flies
- transmits Onchocerca gutturosa of cattle and O. volvulus of man (in Africa - river blindness)
- effect on hosts : severe irritation
Phlebotomus identification and significance for vets
sand fly - hairy wings Significance - vectors of protozoan disease leishmaniasis ○ Painful lesions, difficult to treat
Culicidae features, larvae, feed, when present, significance and control
- larvae aquatic
- females feed on blood
- males non-parasitic
- diurnal, nocturnal or crepuscular - if you know when they bite can use as a control method
Significance :
cause : irritation, blood loss - act as vectors*****
Viruses : yellow fever, equine encephalitis, dengue, zika
Protozoa : malaria
Nematodes : Dirofilaria immitis - heart worm
Control : removing breeding sites; repellents
Features of Brachycera how large, antennae, pain, larvae, where found and significance
Horse and march flies - very large, slow flies - short antennae (looks like mustache) - very painful bite - larval stages aquatic - coasts and forests along creeks Significance - effects on host : irritation and blood loss - vectors for trypanosomes, anthrax, some nematodes (as they are so large)
What are the two main features of cyclorrhapha
- Short antenna with arista
- flies that breed in vegetable or animal material
Features of Oestridae - Oestrus
size, mouth piece, eggs, larvae
- large flies (may resemble bees)
- vestigial mouth parts - cannot feed - not parasitic at this stage
- lay eggs or are viviparous (lay live young)
- LARVAE ARE PARASITIC
○ larvae are endoparasites
○ three larval stages in host
pupate on ground - needs to have a thick outer shell, some have spines
Gasterophilus what is it, what larval stages, pathogenesis and eggs
- 3 larval stages within the stomach
- Not a lot of pathogenesis involved
- Lay eggs on legs, annoying and sticky so horse bite them off and ingest
List the 3 species of Gasterophilus and how to identify with eggs, colour, where found and how hatch
1) G. intestinalis eggs yellow, anywhere on front of body, hatch when licked (eaten)
2) G. nasalis eggs pale, laid between mandibles, hatch spontaneously
3) G. haemorrhoidalis eggs black, laid around lips, hatch spontaneously
Gasterophilus where are the first, second and third instars found
First instar : migrates though mouth and gums
- Can be quite painful
Second instar : attaches in stomach - bathing in nutrients
Third instar : in stomach