Parasitology 3 Flashcards
Ostertagia common name, size, location and features
(“brown stomach worm”) Size: ~9 mm Location: abomasum Features: • cervical papillae • spicules terminate in 3 stubby hooked processes • small vulval flap, not as large
Ostertagia circumcinta what are the 6 steps in the lifecycle and PPP
Life cycle: direct
1) L1-L3 in faeces (~ 2 wks) - environment
2) L3 ingested and animals become infected
3) exsheaths in rumen
4) migrates into the lumen of abomasal gland
5) moults to L4
6) L4 returns to lumen of abomasum
• PPP = 21 days
Ostertagia in sheep what is important with the lifecycle and list 7 effects on the host
HYPOBIOSIS - common (6 months)
• cause nodules in abomasum - due to inflammatory response
• Occurs in summer
• larvae become inhibited in spring, emerge in autumn
Effects on the host:
Important in south-east Australia (Victoria)
1) pH rises to 6
2) protein digestion stops
3) plasma pepsinogen rises
4) hypergastrinaemia
5) hypoproteinaemia
6) anorexia - leakage of nutrition and not absorbed
7) diarrhoea - decrease absorption
Ostertagia in sheep describe the effect on host
When in lumen destroy epithelial cells
- Increase mucus production
- Hypoplasia and metaplasia occurs of the epithelial cells
Also damage other cells:
1. Cells that produce acid - parietal cells
- Damaged so increase pH in abomasum
2. Cells that produce pepsinogen - chief cells
- Pepsinogen not converted into pepsin due to high Ph
- The pepsinogen will then be absorbed into the circulation - HIGH PEPSINOGEN
Combination of high pH and excretory products from worms LEADS TO
- Increase production in gastrin, locally absorbed, leading to hypergastrinaemia
Ostertagia in sheep immunity
The abomasum adapts to the parasite
• develops in older animals - younger animals are more susceptible
○ If older animals get infected generally have subclinical infections
• worm burden expelled
• remaining worms small & produce few eggs
Ostertagia, Ostertagi what is important about it, what does it lead to within the host and the 2 differernces from sheep
Most important nematode in cattle in temperate areas of the world
• basic life cycle similar to Ostertagia in sheep
causes nodules and oedema in abomasum
- severe infestation gives “Morocco leather” appearance
Differences from sheep:
1. Faecal mass as a reservoir for larvae
2. Inhibited larvae can emerge synchronously
Ostertagia, Ostertagi epidemiology of larvae, where found, emerge and when does hypobiosis occur
cattle dung pat - “helminthological time bomb”
○ water content and temperature within dung pat play crucial role in hatching of eggs and the development of larvae
• larvae can survive for extended periods in faecal pat
• emerge following rain
Hypobiosis not understood
Southern Hemisphere - in summer
Northern Hemisphere - in winter
What occurs with type 1 and 2 ostertagiasis and when occur in southern australia
Type 1 ostertagiasis - Winter
• young animals
• no immunity
• occurs in winter
Type 2 ostertagiasis - Autumn
• larvae emerge synchronously - L4 hypobiosis larvae - 1000’s emerge
• 2-4 year old animals
• induced by “stress” (calving) - IMMUNOCOMPROMISED ANIMALS
• occurs in autumn - during summer larvae undergo hypobiosis so when change in weather they emerge if immunocompromised
Trichostrongylus axei common name, host, location, size and features
Stomach hairworm
Host: primarily parasitic in cattle; can occur in sheep, horses, pigs, humans
- Wide host range
Location: abomasum/stomach (intraepithelial)
• size ~ 6 mm - smallest that occurs in the abomasum
Features
• spicules - unequal, dissimilar
Trichostrongylus axei pathogensis and epidemiology
Pathogenesis: - similar to Ostertagia • damages epithelium - develops within epithelial cells • protein lost into lumen • mucus produced, pH rises • 40,000 can kill lamb Epidemiology: • important in mixed grazing - Cattle and lambs
What are the 2 most important nematodes of sheep in south-east Australia
1) Trichostrongyles
2. ostertagia
What are the 3 main parasites of sheep and relative costs and what contributes to the production loss
1) Fly strike - 173.2
2) Lice - 81.1
3) liver fluke - 24.8
Production losses
• fleece weight and staple strength
• ewe live weight and fertility
• lamb growth rate
• ↓weaning weight - increased deaths
What are the 3 main parasites of beef and relative costs
1) cattle tick - 161.0
2) Buffalo - 98.6
3) Internal parasites - 93.6
Trichostrongyles of ruminants what occurs with infection, control vs eradication
• Infections always mixed
• All animals are infected all the time while grazing - some animals have a heavier burden that others
• Control rather than eradicate
○ eradication is impossible
§ would leave susceptible sheep and cattle
What are the 3 main targets of trichostrongyles lifecycle
1) Parasitic stage - what occurs within the host
2) Contaminating stage
- How does the egg survive on the pasture
3) Infectious stage
- How does the infectious stage survive on the pasture
What are the 5 features that affect the epidemiology of trichostrongyles
- Moisture - different rainfall zones within Australia help us predict the parasites that are present
- Temperature
- Grazing factors
- Host factors
- Management factors
List 2 ways moisture effect epidemiology of trichostrongyles
1) needed for development of L3 in faeces (infective stage)
2) larvae to migrate onto pasture
Lateral movement - assisted by heavy rain & flood (growth of fungal spores travel on)
Vertical movement - via dew drop movement (dusk and dawn as sheep eat and less UV)
Trichostrongyles why is temperature important and what occurs with low and high temperature
Important for development of eggs and larvae
mild Australian temperatures have little effect except: Haemonchus >10º C - requires a higher temperature
• low temperature can slow egg hatching & development in some species
• high temperatures shorten survival times of L3’s on pasture
Trichostrongylus Colubriformis and Rugatus what temperature occur with
T. Colubriformis
- Need higher temperature for eggs to hatch as generally higher temperature areas
T. Rugatus
- Occurs in dry areas so longer survival in areas with less moisture (humidity)
List and describe 3 grazing factors that affect the epidemiology of trichostrongyloidosis
1) not uniform grazing so uneven defecation -> avoid high parasite areas -> eventually grass will grow and sheep will eat and become infected
2) Type of vegetation - height and species -> higher more protection for L3 (infectious) larvae
3) stocking rate - high stocking rate initally heavier contaimination overtime reduce infection due to overgrazing (UV exposure)
List and describe 3 host factors that affect the epidemiology of trichostrongyloidosis
1) age - younger animals
2) genetic susceptibility - skewed worm burden and faecal egg counts
3) Breed differences - merinos more susceptible than , no breeds completely resistant
In northern hemisphere and southern hemisphere what are the season in which rises in faecal egg counts occur and why
Northern hemisphere in spring
1) Ewes that are going to give birth to lambs worm count increase in spring due to relaxation in immunity - increase susceptibility to L3s
2) Larvae who had undergo hypobiosis reactivated and lead to high faecal egg count in ewes
3) Faecal egg count reaches maximum in summer
Southern hemisphere in autumn - autumn rise phenonium
1) During summer get hypobiosis therefore ewes that give birth to lambs in autumn
List 4 management factors that affect epidemiology of trichostrongyloidosis
- Time of lambing
○ Autumn lambing - increase in faecal egg count as discussed above - Grazing management
○ Over or under grazing - Nutritional status of animals
○ If healthy can withstand higher burden of parasites
○ If low condition score can get large clinical signs in same amount of burden - Strategic use of anthelmintics
○ When in the lifecycle are we going to get the maximum - dependent on temperature and moisture for free-living stages
List 3 factors supporting hypobiosis and 2 supporting reactivated of inhibited larvae
Factors supporting hypobiosis
1) unfavorable climatic conditions - increase
2) immune status of animals
3) Density of GINs - if high amount of adults within L4 will undergo hypobiosis until they are naturally or chemically cleared and then resume their development
Factors supporting the resumption of the development of inhibited larvae
1) hormonal changes
2) alterations in the components of immune system during the PPR
3) density dependence of parasite
List 6 ways to diagnosis Trichostrongyloidosis and which is gold standard
- faecal egg counts
- faecal cultures
- molecular identification of trichostrongylid nematodes
- haematology, biochemistry and serology
- pasture larval counts
- total worm counts - GOLD STANDARD
How many eggs per day does Haemonchus, Trichostrongylus and Nematodirus lay
Haemonchus 5000-10,000 eggs/female/day
Trichostrongylus 10-200 eggs/female/day
Nematodirus 50 eggs/female/day
Faecal egg count what used for, how done and advantages and disadvantages
- Used to give a rough guide on worm burden in the herd
- Count eggs of parasite within a known volume of fluid - need to find the eggs per gram of faeces (epg)
Ad - can be carried out in the field
- host immunity may suppress egg production
- allows you to test chemicas
Dis - variability in degree of infection between individuals
- indicated presence of females only
- difficult to identify eggs to genus need to carry out larval culture
Faecal cultures what used for, advantage and disadvantage
• identification of nematode larvae
Adv - permits determination of the composition of worm burdens
Dis -cultures require an incubator set at 25-27°C which limits its use in the field
FAMACHA what is it, what nematode used for, when used and disadvantage
Haemonchus contortus ONLY
- measures levels of anaemia or blood loss (not faecal egg counts) and treatment decisions are based on these levels
- only when animals displaying clinical signs
Adv
- Decrease in the amount and frequency of treatment for the majority of the herd.
- Slows the development of anthelmintic resistance.
Dis
- Major issue is the cost associated with labour therefore not widely used in Australia
Pasture larval counts what does it estimate, advantages and disadvantages
Direct quantification from pasture
• estimate no of larvae/kg of herbage by collecting different samples from the paddocks
Dis
• slow
• does not detect low levels of contamination*
• non random distribution of larvae in paddock makes sampling difficult
Adv
• can be useful in comparing paddocks
Total worm counts how done and what can assess
Direct assessment from sacrificed animals (either very sick with high burden or introduce naive lamb to pasture and after 3-5 weeks slaughter)
- Can identify genera and species
In south-east Australia when is it most effective to treat and when is it ineffective
- Effective treatments in summer
○ 1st Nov - Dec -> all worms get in spring will kill
○ 2nd end of summer -> if picking up worms during summer
○ When move to low burden (due to paddock spelling, rotational grazing etc) pasture in winter time, will maintain low burden - If treat in mid-winter, L3 already on the pasture so treating the animal will kill the ones within the body but they will just get reinfected - INEFFECTIVE
List 6 ways to control trichostrongyloidosis
1) Paddock spelling - effective in summer to exposure to UV
2) rotational grazing - exposure larvae to heat and UV
3) crops - use of stubble - when feeding will decrease parasites
4) Alternative grazing - sheep and cattle alternating (not T. axei)
5) Anthelmintic drug - timing most effective 2 in summer
6) Smart grazing - merino weathers are the most susceptible to parasite infection
List the 8 steps in smart grazing
1) October select paddock to prepare for merino weathers in the winter of next year + select older animals
2) November bring in older animals to that paddock after treatment (deworming) using 2.5-3times the stocking density
○ Overgrazing paddock
3) December move older animals to another paddock
4) December to January don’t allow any animals to graze the pasture -> paddock spelling
5) February deworm the older animals again, and again bring to the same paddock for over grazing
6) After one month grazing in paddock move animals to another paddock
7) Throughout March and April leave the paddock -> paddock spelling
8) Throughout Winter graze the merino weaners on this paddock that now has a very low burden of worms
Hyostrongylus rubidus host, where found, lifecycle, PPP, clinical signs and control
Pig - stomach direct life cycle L3 in gastric glands PPP = 21 days causes diarrhoea, weight loss in piglets controlled on concrete floors
Ollulanus tricuspis host, where found, size, features, pathogenesis and transmission
Cat - stomach
- minute nematode (1 mm)
- female has a tail with 3-4 short cusps
- viviparous (L1-L3 develops within uterus)
- not very pathogenic
- L3 is transmitted in vomit - other cat that eat the vomit will become infected
Amidostomum anseris host, location, pathogenesis
(gizzard worm)
• ducks, geese, swans
• junction of gizzard & proventriculus
• larvae penetrate the thickened layer of gizzard lining
• highly pathogenic in large numbers
Trichostrongylus tenuis host, location, clinical signs, control
- found in caecum of galliform birds
- wide host range
- nodules & mortalities in galliform birds
- controls wild grouse populations -> help to maintain
Superfamiy Strongyloidea common name, location and PPP
strongyles Large intestine (rarely kidney or trachea) PPP varies as some species have extra-intestinal migration therefore pre-patent period becomes longer
Strongyloidea features, main hosts and larvae stages where present
Features • Medium to large • bursa in male • large well developed buccal capsule • leaf crown - finger like at the end of the buccal capsule ○ One or two rows Hosts - horses, ruminants, pigs, birds, elephants Life cycle L1 - L3 - faeces L3 - herbage L3 migrate - into intestinal gland L4 emerges - to lumen Final moult - in lumen
What are the 2 main sibfamilies of Strongyloidea and their defining characteristics
1) Strongylinea
- globular (large) buccal capsule
- called “large strongyles” - larger in size
2) Cyathostominae
- cylindrical buccal capsule
- called “small strongyles”
Strongylus what are the 3 main species for horses, what also called and location
Strongylus = red-worms/blood-worms 1) S. vulgaris 2) S. edentatus 3) S. equinus Location: caecum and colon
Strongylus vulgaris list the 12 steps in the lifecycle
Life cycle: direct
1. Adult in large intestines and lay eggs
2. L1 and L2 develop in faeces within environment, feed on bacteria
3. Development to L3 (infective stage) stops below 8ºC
4. While grazing animals will pick up L3
5. L3 exsheaths in small/large intestine
6. migrates into intestinal wall and penetrates intestinal mucosa - stay for 1 week
7. Develop into L4
8. L4 Migrate/penetrates arterioles and then wall of arteries (caecal arteries) and ascends to root of cranial mesenteric arteries
○ Moving against the blood flow -> moving towards the aorta
9. remains for several weeks (3 - 4 months)
10. returns to gut via blood stream
11. Intestinal wall where form a nodule, undergo a moult within and then move into the lumen of the intestines
12. Once in the lumen the adults feed on blood
Strongylus vulgaris host, size and PP
Horse,
size -14 to 24 mm
PPP = 6 months
Strongylus vulgaris effects on host in its two stages
Migrating larvae
1) damage arterial wall -> thrombus formation -> obstruction -> ischaemic necrosis
2) Lesion “verminous arteritis” (inflammation of arterial walls)
3) intermittent colic to infarction
Adult
Blood feeders -> if continue to bleed anaemia, eosinophilia
Epidemiology of Strongylus vulgaris in australia
Not too much information on these genera in Australia
common, cosmopolitan prevalence was 85%, now 25% in Victoria
• larvae most abundant on pastures in spring desiccated in summer, winter stops larval development
○ Hot and dry larvae present on pasture won’t survive - control methods for Trichostrongyles can be used here
• foals develop immunity after repeated exposure
Strongylus edentatus host, features, PPP and effect on host
Host - horse Features • buccal capsule is wider anteriorly than posteriorly • no teeth in buccal capsule • very common species • larger than S. vulgaris (2.3-4.4 cm) PPP = 10 months Effect on host: • aberrant larvae found in many organs • migrating larvae cause lesions • adults cause anaemia
Life cycle of strongylus edentatus list the 6 steps within the host
- L3 exsheaths in caecum
- burrows into gut wall and enters portal veins to move into liver where moults to L4
- L4 migrates within the liver parenchyma - 8- 10 weeks
- migrates to sub-peritoneal tissues
- Penetrates intestinal wall form nodule and undergo final moult -> adult
- Move into the lumen and suck blood
Strongylus equinus host, features, PPP and effect n host
Host - horse Features: • 3 teeth in buccal capsule • deepest buccal capsule • tropical species PPP = 8 months Effect on host: - Depending on number of worms can get issues in liver and pancreas - migration of larvae - Asymptomatic infection - Anaemia - adult worms
Strongylus equinus what are the 8 steps in the lifecycle within the host
- L3 exsheaths in caecum
- L3 migrates/penetrates into gut wall
- Undergoes moult to L4
- L4 move into peritoneal cavity and penetrate the liver
- spends 6-7 weeks in liver
- migrates via pancreas to gut
- Form nodule in gut wall, final moult
- Adults move into lumen and begin to suck blood
Genus Triodontophorus what is it and host, main features and effect on host
Large strongyle of the horse Features - bearing 3 teeth Effect on host: • graze on epithelial lining of gut • occur in groups - up to 20 ○ cause ulceration & blood loss within the large intestine
Genus Triodontophorus what is it, host and lifecycle with PPP
Large strongyle of the horse No extra intestinal migration unlike other large strongyles therefore shorter PPP 1. L3 exsheaths in caecum 2. L3 migrates into mucosal gland 3. moults to L4 4. L4 emerges into lumen of large intestine 5. final moult in lumen PPP = 9 weeks
Subfamily cyathostominae what is it, host, features and effect on host
Small strongyles of the horse
Features
- cylindrical buccal capsule with no teeth
Effect on host
Occur in large number, gut content feeders NO BLOOD
-> common within clinical signs (only if very large numbers)
Genus Cyathostomum lifecycle wtihin the host, PPP
- Ingest while grazing
- L3 exsheath in caecum
- enters caecal glands
- moults to L4
- L4 re-emerges to lumen
- final moult in lumen within a cyst
- hypobiosis can occur within the cyst
- When within a cyst protected from anthelmintic such as ivermectin (ivermectin will just kill the adults within the lumen)
PPP = 5 weeks minimum
Genus Cyathostomum effect on host
adults feed on gut content
• not pathogenic
• very large numbers (1x106) cause diarrhoea
• normally 115,000 larvae encysted- visible from external surface -> massive emergence causes severe diarrhoea and can kill the horses
Genus Cyathostomum 3 ways to diagnose
1) find eggs in faeces - most of the eggs will be small strongyles as present in large numbers and hybobiotic larvae not susceptible to many anthelmintic
2) use McMaster chamber
• >300 epg pathogenic
3) larval culture to identify genera
List the most common strongyle of horses at the following ages:
1) First 2 - 3 months
2) adult
1) Strongyloides westeri - first 2 - 3 months - problem for foals
- Trans mammary transmission
2) Adult strongyles - large and small generally trichostrongyloidea nad strongyloidea
Family Chabertiidae what are the 2 subfamilies their features, what feed on and main genera
1) Chabertiinae
- globular (large) buccal capsule
- tissue feeders
Genera - Chabertia
2) Oesophagostrominae
- cylindrical buccal capsule
- gut content feeders
Genera - Oesophagostomum
Chabertia ovina host, location, size and features
Hosts: sheep, goats, cattle - small and large ruminants
Location: colon (first coil)
- size 1.5-2.0 cm - largest present within the colon
Features:
- bell-shaped buccal capsule (directed ventrally) with no teeth
- tiny leaf crown, cannot see in light microscopy
Chabertia ovina life cycle and PPP
- L3 exsheaths in small intestine
- enters mucosal glands
- moults to L4
- L4 returns to lumen
- migrates to large intestine
- final moult in colon
- Adult worms feed on mucosa of large intestine
PPP = 8 weeks
Chabertia ovina effect on host, what area generally found and immunity
Effect on host:
• feed on mucosa
• cause haemorrhage
• excess mucus production
• diarrhoea - most common
• cosmopolitan parasite but more prevalent in temperate areas - south eastern parts of the country
• strong immunity develops within younger animals - young animals are susceptible
• usually only few worms present (3,000 eggs per day) -> 200 pathogenic
Genus Oesophagostomum what is it. common name, lifecycle and PPP
Strongyle of ruminants
Nodule worm
1. L3 migrates into glands in small &/or large intestine
2. L4 emerges and migrates to large intestine (colon or caecum)
PPP = 5-6 weeks
Genus Oesophagostomum 3 main species, host and site
O. radiatum - cattle - caecum
O. columbianum - sheep - colon
O. venulosum - sheep - caecum
Oesophagostomum radiatum what is it, host, location and features
strongyle of cattle Location: caecum/colon Features: • cylindrical buccal capsule in adult, L4 more globular • small leaf crown • no external leaf crown • cervical collar in 2 parts
Oesophagostomum radiatum effect on host
1st exposure - no reaction to susceptible host
2nd exposure - Hypersensitivity type 1 reaction
○ Large amount of cysts produced -> can lead to ‘pimply gut’
○ nodule filled with eosinophils, larva killed, caseous lesion calcifies
○ nodules cause Hb & plasma proteins to leak into gut
§ interfere with gut motility
- diarrhoea, anorexia
Oesophagostomum columbianum what is it, host, location and pathogenicity
Strongyle of sheep
location - colon
•Highly pathogenic
• prolific females
Oesophagostomum venulosum what is it, host, location, pathogenicity
Strongyles of sheep location: caecum • non-pathogenic, some scouring • very common in sheep • prolific egg layers (3000/female/day) • typical strongylid eggs
What are the 2 main strongyles of the pig within the large intestines
Oesophagostomum dentatum
- nodule worm of the pig
Oe. quadrispinulatum
- significant pathogen in pigs
Stephanurus dentatus host, location, distrubution and features
The kidney worm of the pig
Location: peri-renal fat in cysts attached to ureter
Distribution:
• limited to warm, moist areas in Australia - northern
• tropical & subtropical areas worldwide
Features
• Cup shape buccal capsule, 5 -6 teeth
Life cycle:
Stephanurus dentatus what is it, host, lifecycle and PPP
The kidney worm of the pig
Life cycle:
1. egg passed in urine**
2. L3 ingested or can penetrate skin
3. migrate to liver via portal system (3 days) or aorta (8- 40 days)
4. migrate in liver for 2-3 months where moult to L4
5. migrate to perirenal area
6. may migrate anywhere in body
7. Goes to the per-renal fat where cyst form in kidney
PPP = 9 months
Stephanurus dentatus what is it effect on host and diagnosis
The kidney worm of the pig Effect on host: • fibrosis in liver - increase in damage hepatic enzymes • abscesses in carcass • organs condemned at slaughter • weight loss Diagnosis: • eggs in urine • elevated liver enzymes
What is the main strongyles of birds, location and features
Syngamus trachea Location - trachea Features - cup-shaped buccal capsule • up to 10 teeth • pair appear Y-shaped grossly (male and female)
Syngamus trachea host, lifecycle and PPP
Birds - poultry
Life cycle:
1. eggs coughed up, swallowed by bird and leave via faces
2. L1-L3 within egg**
3. molluscs, oligochaetes paratenic hosts (no development within) ingest faeces
4. L3 ingested by birds via ingestion of paratenic host
5. migrate to trachea via liver then lungs
PPP = 2 weeks
Syngamus trachea host effect of host, diagnosis and control
Birds - mainly poultry Effect on host: • cause excess mucus production • block airways • respiratory distress - birds stand “gaping” • blood feeders Diagnosis: • eggs in faeces (ellipsoidal thin-shelled eggs with a thick operculum at both sides) Control • broad-spectrum anthelmintic use
Superfamily Ancylostomatoidea features, location, food and hosts
Hook worms Features: • head bent dorsally - looks like a thumb • large buccal capsule • teeth or cutting plates • bursa in male • infect the host either orally or by skin penetration Location: small intestine Food: blood or tissues Hosts: • dogs***, cats, ruminants, pigs • humans***
What are the 2 main subfamilies within Ancylostomatoidea and their differentiating features
1) Ancylostomatinae - teeth (number identifies species)
2) Bunostominae - cutting plates
Ancylostomatoidea what is it, lifecycle and the 2 main PPP
Hookworms
Male and female in small intestine
Female worms are very prolific -> 20,000 eggs per day for some species
- Eggs passes in faeces
- Development L1-L3 in environment
- Entry into host
1. Penetrate the skin - secrete enzymes that allow penetration
○ Circulation -> heart -> lungs -> pharynx -> swallowed -> small intestines
§ PPP = 4-5 weeks
2. Ingest L3
○ Straight into small intestine not extra-migration
§ PPP = 2-3 weeks
- Exshealthment -> L4 -> adult worms
What are the 3 main hookworms of dogs and their defining features
Ancylostoma Canium -> 3 pairs of teeth
Ancylostoma braziliense - 1 pair of teeth
Uncinaria Stenocephala - cutting blades
Ancylostoma caninum what is it and host, what are the 2 important transmissions and max PPP
Hookworms of dog
1) skin penetration -oesophagus or oral cavity in addition to the skin -> undergoes same route
2) trans mammary infection important - L3 wont’ develop, encyst in muscles and remain dormant (resistant to normal treatment) -> pre and post partition) -> larvae activated during partition (hormonal activation) -> travel through milk into pups -> will develop quickly
○ PPP max 2 weeks
Ancylostoma caninum what is it, host and effects on the host and zoonoses
Hookworms of dog
1) blood feeders - female 0.1ml/day
2) black tarry faeces - undigested blood
3) microctyic hypochromic anaemia
• heavy infections (pups) cause death
• strong immunity following exposure - with lower dose therefore primarily a problem of young dogs
• can cause eosinophilic enteritis in man - ZOONOTIC
Ancylostoma caninum epidemiology and diagnosis
Common in warm climates - tropical and subtropical -> not major issue in Victoria - sandy areas ideal for larvae Diagnosis 1) identify egg in faeces 2) egg countrs (high >5000)
Ancylostoma braziliense what is it, where common, transmission, pathogenitic effect in host and humans
Hookworm of dogs
• common in tropical & sub-tropical regions
• no trans-mammary transmission
• less pathogenic - can cause hypoproteinaemia and diarrhoea
• primary cause of “cutaneous larva migrans” or “creeping eruption” in man (don’t develop to adults in humans)
Uncinaria stenocephala what is it, where common, transmission, pathogenesis
Hookworms of dogs
• common in cooler area - VICTORIA IS A PROBLEM
• L3 are ingested - oral ingestion
• no extra-intestinal migration
• less pathogenic, mainly lead to diarrhoea with high burden
Uncinaria lucasi what is it, host, where found, important route of infection
Hookworm of seal
• serious pathogen in northern hemisphere seals
• transmammary transmission most important route of infection
○ L3 in the milk to nursing pups -> develop to adult worms -> eggs passed in faeces of pups -> develop to L3 on the sand -> L3 penetrate the flippers of adult sealions -> move into different tissues
○ Adult worms mainly in pups, Larvae penetration and migration mainly in adults
§ Pups can be killed by the presence of adult worms
What are the 3 hookwroms of cats and their pathogenic effects
1) Ancylostoma brazillense
2) Uncinaria Stenocephala
3) Ancylostoma tubaeforme
Similar to hookworms of dogs
What are the 2 hookworms of ruminants and host
Bunostomum phlebotomum - cattle
Bunostomum trigonocephalum - sheep
Genus Bunostomum what is it, main host, features and PPP
Hookworms of ruminants Features: • found mainly in warm areas - tropical and sub-tropical • skin penetration - major • transcolostral infection PPP = 7 weeks
Gaigeria pachyscelis what is it, host, distrubution and effects on host
Hookworm of goat and wild ruminants
- Distribution: Africa, South America, Indonesia
- Effects on hosts:
• feeds on blood - severe anaemia and death
• infections with 25 nematodes - fatal - based on case studies
What is the main genus for hookworm of pigs, where found, lifecycle and pathogenic effects
Globocephalus spp.
Tropics, unknown if in australia
lifecycle - not well know
pathogenic effects: anaemia and weight loss
Metastrongyloidea what are they and main features
Lungworms Features: • small buccal capsule • reduced bursa • mainly found in respiratory system*** (or connected to it – vascular and nervous system)
What are the 3 lifecycles of lung worms, host and genus using these and the general feature
1) Simple direct Host -ruminants & horse Genus : Dictyocaulus 2) Intermediate Host -ruminants, pigs & cats. Genus: Protostrongylus, Muellerius, Metastrongylus, Aelurostrongylus 3) Direct Host -dogs Genera : Oslerus, Filaroides ALL - L1 passes in faeces
List the steps in the simple direct lifecycle of lungworms
- Adults in respiratory system and lay eggs in GIT
- Eggs hatch into gastrointestinal tract
- L1-L3 in faeces in environment, L3 ingested while grazing
- L3 penetrate mucosa of small intestine
- migrates to lungs via lymphatic system (lymph nodes (undergo development to L4)
List the steps in the intermediate host lifecycle of lungworms
- L1-L3 in molluscs or earthworms, L3 ingested within mollucsc
- L3 penetrate mucosa of small intestine
- migrates via lymphatics to lungs
- L3 - L4 and L4- adults occurs within the lungs
List the steps in the direct lifecycle of lungworms
- L1 past in faeces
- L1 ingested and infects definitive host
○ No development within environment - L1 penetrate mucosa of small intestine
- Goes to lungs via lymphatics
- All moults occurs within the lungs
What are the 3 lungworms of sheep and location within lungs
1) Dictyocaulus filaria - bronchi
2) Protostrongylus rufescens - bronchioles
3) Muellerius capillaris - alveoli
Dictyocaulus filaria what is it and host, location and features
Lungworms of sheep
Bronchi
Features:
• long thin worm (10cm) - longest in sheep
• small buccal capsule
• “spongy” spicules
• ovoviviparous -> L1 already within the egg
Dictyocaulus filaria what is ti and host, life cycle and PPP
Lungworms of sheep
Life cycle: SIMPLE DIRECT
1) Female in bronchi at tracheal bifurcation
- characteristic cap on larva’s head
2) L1 to the pharynx -> swallowed
○ L1 can survive in GIT tract with multiple enzymes
3) L1 in faeces
4) L1 - L3 in environment
5) L3 migrates onto herbage, ingested
6) exsheaths in abomasum
7) Penetrate intestinal mucosa
8) migrate to lungs via lymphatics (mesenteric lymph nodes undergo moult L3 - L4)
9) L4 -> adult in lungs then go to predilection site (bronchi)
• PPP = 21 days
Dictyocaulus filaria what is effects on host and clinical signs
Lungworm of sheep
1) block ariways via excess mucus production
2) damage epithelium - loss of mucocillary
3) intestinal pneumonia
4) alveoli fill with fluid - chronic cough, laboured breathing
5) detachment alveolar macrophages - secondary bacterial infection
Possible death
Protostrongylus rufescens what is it, host, features and effect on host
Lungworm of sheep Features: • to 65 mm long • slender, red worm • in small bronchi & bronchioles Effects on host • mild pneumonia - heavy infestation • most infections subclinical
Muellerius capillaris what is it host, feature, location, lifecycle and effect on host
Lugnworms of sheep Feature: • tiny coiled worms in alveoli Life cycle: INDIRECT LIFECYCLE • snail & slug intermediate hosts Effects on the host: • high prevalence • virtually non-pathogenic in sheep • can be highly pathogenic in goats
