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Nematodes 2 Flashcards

1
Q

Ascarids: general features

A
  • LARGE (esp females)
    • males= 2 spicules & coilded tail
  • live in lumen (SI) gut content feeders
  • 3 large lips
    • esophagus may have ventriculus
    • +/- cervical alae
  • COMMON world wide
    • esp young animals
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2
Q

who produces this egg and how many?

A
  • Ascarids - thick shelled and highly resistant
  • a lot!! prolific egg layers (200,000 egg/day)
    • milky media
  • shed in feces & larva develops to infective stage inside egg & egg ingested
  • eggs are sticky
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3
Q

What is the general ascarid life cycle?

A
  • in environment (soil crucial for development) for 2-4 wks
  • direct LC w/ +/- transport host (earthworm)
  • egg laid in feces > larva develps to L3 in egg & egg ingested
    • free (L3) larvae penetrate SI/LI mucosa > enter portal venules to LIVER > LUNG> alveoli to bronchi- (HEPATOPULMONARY MIGRATION) > bronchi migration to trachea, pharynx and swallowed (TRACHEAL MIGRATION)
    • L4 reach SI about 2-3 wks post infection > adult in SI and lay eggs
  • PPP= 2 mo
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4
Q

What aspects of the ascarid life cycle are important to control?

A
  • young animals are clinically affected
  • older animals are reservoirs
    • strong exposure = induced immunity = lower burden
  • eggs are very resistant
  • zoonosis - humans are also definitve hosts
    • adults: ascaris suum - pig/human
    • larvae: toxocara canis and T. cati - ocular and visceral migrans
    • larvae: anisakids - eosinophilic gastritis (fish borne- consuming raw fish)
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5
Q

what is the ascarid that infects pigs? LC pattern?

A
  • Ascaris suum
  • Ascaris lumbricoides
    • site: SI
    • LC: direct +/- paratenic hosts
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6
Q

Pathogenesis of Adult Ascarids

A
  • less pathogenic
  • production & economic losses
    • luminal feeders, malnutrition, reduced weight gain, stunting (kids)
    • worms may secrete anti-pepsin and anti-trypsin enzymes
  • Clinical disease
    • diarrhea, colic, vomiting
    • intestinal ileus, blockage, rupture > peritonitis
    • bile duct occlusion (cholestasis)
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7
Q

Pathogenesis of what nematode & life stage?

A
  • larval ascarids
  • HPM - mechanial & inflammatory damage to organs
    • milk spots in pigs
  • “eosinophilic” pneumonia - calves, pigliets, pups, kittens, foals (asthma-like)
    • predispose to viral and bacterial pneumonia
  • A. suum in cattle lungs causes anaphylaxis
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8
Q

are ascarids host specific?

A

No, larval stages will undergo extensive migration

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9
Q

Ascarids of the horse?

A

Parascaris equorum

*SI and direct LC - very large worms

* peak egg counts in foals 15-18 wks old

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10
Q

Ascarids of dogs & cats

A

Toxocara canis - dog

Toxocara cati- cat

Toxascaris leonina - dog & cat

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11
Q

Toxascaris leonina (arrow worm)

  • Life cycle & host
A

cats and less frequently dogs

  • soft shelled eggs
  • larvae hatch and penetrate SI mucosa > L4 > adult
  • no migration
  • Paratenic hosts - rodents, arthropods, lizards
  • PPP= 7-10 wks
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12
Q

Toxocara canis

  • LIFE CYCLE
    • important migration/transmission patterns
A
  • egg thick shelled & sticky (adverse to environment)
    • 2 moults w/in egg - L3 infective stage in egg
  • egg ingested by a pup
    • hatch in SI > hepatopulmonary migration & moult L4 > tracheal migration > final moult in SI and lay eggs
    • PPP= 4-5 wks
    • as dogs mature tracheal migration less frequent
      • larvae pass though lung capillaries and distribute to other organs > encyst and developmentally arrest
      • female animals: somatic larvae activate and migrate in last weeks of pregnancy
        • transplacental migration - carried through umbilical vein to fetal liver> lungs
          • after birth: larvae undergo tracheal migration & develop to adults
            • pups pass eggs at 3 wks old
        • transmammary migration - infect while suckling and larva devlop to adult in SI
  • Paratenic host: mice, rats, lizards, arthropods
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13
Q

Who is most likely to have severe infection with Toxocara canis?

A

young, unweaned pups

*clinical signs can develop as young as 3 wks (coughing, failure to grow, pot belly)

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14
Q
A

A. Ascaris - pigs/humans

B. toxocara spp. - dogs, cats, cows

  • dark circular rough

C. toxascaris spp. - dogs/cats

  • smooth oval

D. parascaris equorum - horses

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15
Q

Toxocara cati

  • Life cycle
A
  • common parasite of cats
  • direct life cycle with traceal migration (paratenic hosts and transmammary migration possible)
    • trans colostral infection occurs
    • no transplacental
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16
Q

Nematode identification & preferred host?

A

A. Toxocara cati - cats

B. Toxocara canis - dogs

C. Toxascaris leonina- dogs/cats

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17
Q

who am I?

A

Toxocara canis & (bottom right - T. cati)

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18
Q

Public health significance of Toxocara spp.?

A

Visceral larval migrans

  • embryonated egg ingested by humans (18 mo - 4 yrs)
  • marked immune response to somatically migrating larvae (encapsulated in tissue for years)
  • clinincal signs
    • urticaria, fever, hepatomegally, eosinophilia, cough
    • usually self limiting
      • +/- eosinophilic encephalitis, myocarditis

Occular larval migrans

  • caused by single larva
  • 8yrs- adult
  • fibrotic lesions in retina > vision loss
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19
Q

Ascarids of ruminants

  • main route of infection?
  • Life cycle?
  • epidemiology?
A
  • Toxocara vitulorum
    • not common
    • excusively calves as transcolostral is the main route of infection
    • Direct LC- no tracheal migration
      • milk, muscles, lungs, liver > SI of calf (L3>L4>adult > eggs)
    • limited to north east coast of AU
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20
Q

Ascarids of birds & their identifying features

A
  • Ascaridia spp (small intestine)
    • esophagus club shaped
    • adult: 12 cm long
  • Heterakis spp (ceca)
    • esophagus with posterior bulb
    • adult: 1.5 cm long

** eggs identical & both males have precloacal suckers

-chickens, turkeys, geese, ducks

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21
Q

Life Cycle of Ascarida galli and Heterakis gallinarum

A
  • Ascarida galli (PPP- 6 wks) & Heterakis gallinarum (PPP= 3wks)
    • L3 develops in thick egg - 2 wks
    • fowl ingests egg > hatch in SI (Heterakis- larva migrate to cecum)
    • larva enter SI mucosa and moult 2x > reemerge to lumen and adults develop
    • quick immunity
    • transport hosts = earthworms
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22
Q

Pathogenesis of Ascarida galli

A
  • chicks 4-8wks old (older birds resistant)
    • larvae moult in SI wall
      • synchronous eruption > enteritis and hemorrhage
    • adult worms: intestinal occulsion
    • nutritional deficiency
      • increased susceptibility to disease
      • poor growth
        *
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23
Q

Pathogenesis of Heterakis gallinarum

A
  • little pathogenic significance (+/- cecal thickening) : LI
  • tranmission of Histomonas meleagridis through egg
    • protozoa not pathogenic to chickens but cause “black disease” in turkeys
    • necrotizing typhlitis and focal necrosis of liver
    • ** dont minx chickens and turkeys
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24
Q

How do you control this ascarid?

A
  • A: Ascardia galli
  • B: Heterakis spp
  • C: eggs are identical - compare to thin shelled strongylid eggs

Control extensive animals - challenging (rotate pastures esp young)

Control intensive animals

  • hygiene - prompt removal of feces
  • decontaminate with bleach
  • rodent/past control (cockroaches)
  • do not feed raw meat
  • treat nd quarantine new arrivals
  • deworm regularrly (esp young)
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25
Treatment of ascarids - general
BZs (fenbendazol) & MLs (ivermectin) most common * water soluble drugs will kill ascarids in gut lumen * pyrantel * lipid soluble drugs will kill migrating larvae * Fendendozole
26
treatment of ascarids in an outdoor system
* treat growers at 8 wks - to prevent high shedding in environment * treat sows and boars every 3 mo * treat sows 7-14 d prior to farrowing * test herd every 6 mo in feed- levamisole, ivermectin, fenbendazole, morantel, piperazine
27
Treatment of ascarids in horses- who is most likely to have a heavy infection? How often do you treat? management?
* foals and yearlings * deworm every 2 mo (rotate ML, BZ and pyrantel) for their first year of life * start at 2 mo/old * rotate pastures for mares and foals annually & fecal hygiene * FEC prior to deworming spring & autumn in adults
28
Treatment of Toxocara canis: pups vs adult dogs?
Pups * 2wks old q2wks until 10 wks old * deworm mother at same time Adults * fecal examination 1-2x/yr
29
How do you treat ascarids during pregnancy?
* does NOT kill arrested larvae - only kills when in circulation * want to prevent TP and TM to pups * Fenbendazole * 50mg/kg DAILY PO from D40 or pregnancy to +14d post whelping * off lable use * Selamectin * topically 40d and 55d of pregnancy * off lable use * Moxidectin * topical * labelled use
30
Treatment of Toxocara cati? Kittens vs adult cats?
Kittens * 3wk old \> q2wks \> until 8wks old \> then monthly until 6mo Adults * fecal exam and deworm according to risk (roaming/indoor) * apply selamectin, moxidectin and emodepside topically to mother at end of gestation
31
Life cycle of Anisakidae
* indirect (stomach-SI) * need marine mammal to complete life cycle * acquired though L3 ingestion: raw or undercooked/smoked fish * zoonotic! * control: cook well or freeze \>7d
32
Pathology of Anisakidiasis
* invasive (1hr -2days) * penetrate gut mucosa * **eosinophilic gastritis** * acute vomiting and dxa * **allergic respose to antigens**
33
Where do you find the adult stage of oxyurids/pinworms?
34
Cecum, colon and rectum \*\*\*Direct life cycle and HIGHLY HOST SPECIFIC
35
Typical pinworms of Horses and Mice
Horses: Oxyuris equi Mice: Syphacia obvelata
36
General life cycle of Oxyurids (example: Oxyuris equi)
37
How do you diagnose this nematode?
Oxyuris equi- oval shaped egg with mucus plug \> use sticky tape method around anus * females can be 7.5cm long
38
Pathogenesis and clinical signs of Oxyurids (pinworms)? What oxyurid is most likely to cause clinical disease?
clinical signs * usually asymptomatic or mildly pathogenic * DD: ectoparasites * **Syphacia obvelata** (mice) * most commonly associated with disease * anal puritis + self multilation * dxa/ intussusceptions/ impactions * rectal prolapse * weight loss
39
How do you treat this nematode? control?
Syphacia obvelata- mice * challenging to control * bc eggs are so sticky * long course fenbendazole or piperazine in water, ivermectin * reduce overcrowding (esp in research lab) * HIGH STANDARD OF HYGIENE
40
Diagnosis? Where do you find this worm? A. B.
* Found in cecum or colon - both in mice * translucent hair like worm (male =1 mm & females 11 mm) A: Syphacia obvelata B: Aspiculuris tetraptera
41
3 features of Spiruids
1. +/- 2 lateral lips 2. esophagus with anterior muscle and posterior glandular sections 3. unequal spicules 4. eggs with L1 (oviparous) or L1 (viviparous) 5. **indirect LC - arthropod IH**
42
Non-Filarid spiruids of horses & Life Cycyle
Habronema microstoma (IH: stomoxys) & Habronema muscae (IH: muscae) * near margo plicatus \> **no nodule** formation * small ulcerations \> hyperplasia and hyperplasia of mucus secreting cells Draschia megastoma * IH: musca fly * chronic eosinophilic gransulomatous **nodule** (1-10cm) \> ulcer
43
Apart from the stomach where else do you see "habronemiosis"?
* Pulmonary * multiple abscesses filled with necrotic debris \> contian parts of nematode larvae * eosinophilic inflammation * Cutaneous * around face, legs, mucosal areas * risk of secondary infection if not treated
44
Diagnosis of A & B...more pathogenic?
A: Draschia megastoma * big mouth -funnel shapped buccal capsule * causes majority of disease B: Habronema spp. * cylindrical buccal capsule
45
After using a saline solution fecal floatation (SG \> 1.20) on horse feces, we found a few of these eggs (may not see a lot bc adults are within a granulomatous nodule). What is this nematode and how will we treat?
Habronema spp. * oxfendazole, moxidectin
46
How do you treat cutaneous habronemiosis? Chronic infections? How do you control?
* cutaneous lesions (L3) \> treat topically * ivermectin * abamectin * moxidectin * chronic infections * corticosteroids * surgical debridement * MLs * cryotherapy Control * fly control - dispose manure * face/eye masks * screens in stables
47
2 main stomach worms of dogs
Spirocerca lupi and Gnathostoma spinigerum
48
3 main stomach worms of cats
Physaloptera praeputialis Cylicospirura felineus Cylicospirura ubequalis
49
Life Cycle of Spirocerca lupi
1. Ingest L3 with dung beetle \> emerge in stomach and penetrate gastric arteries \> aorta 2. form nodules in aorta \> L4\> migrate from aorta to esophagus 3. nodules in esophagus \> adults emerge and lay eggs in esophagus 4. eggs passed in feces (L1 inside egg) \> ingested by dung beetle
50
Dog in tropical/subtropical region presents with regurgitation, vomiting and weight loss. A few eggs were found in the feces (see picture). There are granulomas in the esophagus. What nematode is this and how do you treat?
Spirocerca lupi * hard to treat because adults in granulomas (also risk of aneurism from migration from aorta to esophagus \> rupture and hemothorax) * Prophylactic : moxidectin (label use) * off label: doramectin, moxidectin and milbemycin for prolonged periods (up to 6 mo) * surgical removal of fibrosarcoma * air feeding - sitting upright * disallow scavenging/free roaming
51
Gnathostoma Life Cycle:
52
A dingo presents with gastritis, vomiting and anorexia, the fecal float had uni-plugged eggs. Will other dingos in the pack show the same clnical signs? What is the pathogenesis and how do you treat?
Gnathostoma * can be asymptomatic * adults embedded in submucosal gastric nodules with tract leading to gastric lumen * +/- secondary infection * adults appear dark red from ingesting blood - although anemia not common * adults also have cephalic bulb * treatment * ivermectin or moxydectin may be efficacious
53
What is the main concern with Gnathostomes?
Human infection (zoonosis) * fish borne (under cooked) * DH= dogs, cats, pigs * **L3 penetrate stomach and undergo larva migrans \> highly puritic subcutaneous swellings**
54
Spiruid that is rarely pathogenic found in pigs and IH is an arthropod?
* Gnathostoma hispidium * usually found in extensive farms
55
Spiruid that is rarely pathogenic found in pigs and IH is a dung beetle?
A: Ascarops stongylina B: Physocephalus sexalatus
56
Clinical signs: blepharitis and mild to severe conjunctivitis, keratitis (opacitiy, ulceration, perforation)
Thelazia spp. * Don't burrow * most commonly seen in cattle
57
Spiruids of Cattle and their predilection?
A: Gonglyonema pulchrum - esophagus B: Gonglyonema verrucosum - rumen
58
Spiruids of Birds- predilection and IH
1. Gonglyonema sp. * crop * IH: cockroach 2. **Acuaria spp.** (picture) * proventriculus * IH: grasshoppers, beetles 3. **Tetrameres spp.** * ventriculus * IH: grasshoppers, beetles 4. Oxyspirura mansoni * conjunctival sac * IH: cockroach
59
Name 5 features of Filarioidea
* adults NOT in GI tract * liquid diet (blood/lymph) * majority vector borne - circulatory is a closed system * primarily viviparous \> L1 = mff * indirect LC * IH= arthropod (mosquitoes, ticks, flies, flea) * female adults long
60
General life cycle of filaria
* L3 injected into host from Simulium bite * L3 in subcutaneous tissues \> adults in nodule * L1 released in skin, lymphatics and blood * black fly takes blood meal and ingests L1
61
Key features of filarioidea in humans
* black flies as vector * onchocerca \> river blindness * adults \> nests in SC tissue * mmf * pruritic dermatitis (lizard skin) * die in eye = inflam\> blindness
62
What is culicoides (biting midge) a vector for in horses? What is the pathogenesis in the definitive host?
* Onchocerca cervicals (adults in nuchal ligament) * edema & granulomatous nodules/fibrosis * "Queensland Itch" * Onchocerca reticulata (adults in flexor tendons) * mobility problems Pathogenesis * dying mff in dermal tissue \> puritic dermatitis * skin of ventral midline, neck, chest, forelegs * scales, crusts, ulcerations, alopecia
63
How do you diagnose and treat Onchocerciasis?
* skin snip or biopsy * mmf rarely in blood unless high burden * Ivermectin & moxidectin * highly efficacious against mff * permethrin pour on (reduce vector)
64
3 Filarioidea of cattle with Culicoides vector and their predilection sites - what is the consequence?
* Onchocerca gutterosa \> nuchal lig * Onchocerca gibsoni \> dermal brisket tissue * carcass condemnation * treat: ivermectin/moxidectin * Onchocerca lienalis \> gastrosplenic ligament
65
Heamatobia irritans (buffalo fly) is the vector for what filarioid of cattle? Predilection and path?
* Stephanofilaria stilesi * adults live in dermis * lesions ventral thorax and abdo * ulcerative and exudative * chronic \> hyperkeratiosis * secondary infection * treat with topical moxidectin
66
What cattle filarioid has a mosquito as a vector and is common in Northern Australia?
* Setaria spp. * large nematode * lies free in abdo cavity * mff in blood
67
How do you diagnose filarioids in cattle?
* skin snip * macerate in warm saline * stephanofilaria mff tiny (~50um) * onchocerca and setaria mff (\>230um) * mff in blood = setaria
68
3 control measure of Stephanofilaria
(common in northern and costal northern NSW) * non chemical control * walk through fly traps * buffalo flies cannot live off host for 1-2hr * dung beetles * synthetic pyrethroids or OPs * pour on, ear tags, dips * vector control * oral ivermectin
69
Main Filarioids of dogs and cats
* heartworm - dirofilaria immitis * subcutaneous nodule worms * dirofilaria repens * looks like D. immitis * Acanocheilonema spp * transmitted through fleas * lymphatic filaria * brugia spp
70
Life Cycle of canine heartworm
* mff in blood \> ingested by mosquito * moult to L3 - 2-3 wks * L3 infective stage transferred to host * moult to L4 \> migrate to chest muscles and abdo (9d to 2 mo) * moult to adult at 2-4 mo \> migrate to pulmonary artery * in right ventricle after 3 mo PPP= 6-7 mo lifespan = 5-8 yrs
71
Pathogenesis of right sided congestive heart failure from heartworm in dogs
* presence of worm * proliferative endarteritis of pulm aa. \> decreased compliance * PLUS thrombosis and thromboembolism * worms cause turbulence * red cells smash and platelets coagulate * pulmonary hypertension * heart pumps harder and cardiac mm thickens * ^ afterload for RV = RV hypertrophy and dilation * RSCHF and caval syndrome * loss of blood flow * blood pooling and edema in chest * organ failure
72
What nematode causes pulmonary arterial disease
dirofilaria immitis * several worms or 1 knotted * thrombosis * inflammation * leakage * can be coughed out * +/- fluid in chest
73
What are the 2 sequelae of caval syndrome caused by heart worm?
* tricuspid valve insufficency * turbulence * mechanical hemolysis * **jaundice** * **anemia** * **hemoglobinuria** * **glomerulonephropathy** * obstuction of bloof flow * decreased cardiac output * congestion (ascites) * collapse of peripheral circ.syst * **circulatory short/death**
74
What are the 4 classes/clinical stages of a heartworm infection
Class 1 * early infection - asymptomatic * mild disease - cough Class 2 * moderate disease - pulmonary arterial disease * cough, exercise intolerance, abnormal lung sounds Class 3 * severe disease - heart murmur, coughing blood, ascites \> heart dysfunction * guarded prognosis Class 4 * caval syndrome - heart failure * jaundice, hemoglobinurea, cardiac murmur * very poor prognosis
75
what are 4 ways to diagnose heartworm in dogs
1. history and clinical signs * endemic area * pups at least 6-7 mo old 2. detection of mff in blood * unstained freshwater smear or buffy coat * concentration methods * knotts test * filtration 3. ELISA to detect adults * Antigen only detected from adult FEMALES 4. up to 30% may be occult * no mff in circulation * males, senile and immature dont produce mff
76
Dirofilaria immitis vs Acanthocheilonema reconditium
* use acid fast to stain * D. immitis * straight body and tail * clumpy and granular in stain * A. reconditium * curved body and hooked tail * diffuse stain * non-pathogenic * flea borne dermal filaria
77
What does the anitgen heartworm test detect?
* adult female worms * at least 3 females for consistent result * higher specificity
78
What is the positive predicitive value
the number of results that are actually positive
79
During days 0-70 of heartworm infection what stage are you killing and what do you use?
L3-L4 use monthly MLs (moxidectin, ivermectin, milbemycin)
80
When can you kill heartworm adults and what compound are you using?
D 120-180 post infection use an adulticidal - melarsomine
81
What is the first step in treating a heart worm infection?
* assess risk (class 1= low class 3/4= high) 1. Strict rest - slow HR at least 4 wks post treatment 2. corticosteroids * prednisolone: pre and 1 month post adulticide * reduce inflammation from dying worms 3. doxycycline for 3-4 weeks * kill endosymbiota (worms bring in gram - bacteria)
82
(step 2) how do you prevent new infections of heartworm and kill mff?
MLs (monthly or long term injectable) - on D0 * kills circulating mff over 7-10d * dont want to kill too quickly \> anaphylaxis * over longer term - 4-12 mo * kill juvenile and adults infertile * prevents new infections of L3
83
How can you kill adult heart worms? when do you repeat the antigen test?
* adulticide - melarsomine * deep IM lumbar injection * kills worms over 4 mo old * first injection * 2nd injection 1 mo later * 3rd injection 24 hrs later * repeat antigen test at 6 mo (after 3rd injection)
84
What is the risk of surgical removal of heart worms when in class 4 (caval syndrome)
* the heart is still in failure
85
If melarsomine isnt available- how do you kill heartworm?
* ML and doxy (1 mo on 2 mo off) over 9 -12mo * caution * clinical signs may worsen * resistance? * dont know when adults are dying
86
name 4 chemo-prophylactic drugs for heartworm
1. revolution 1. selamectin 2. proheart 1. moxidectin 3. advocate 1. imidacloprid 4. HeartGard 1. ivermectin/pyrantel
87
Life Cycle of Heartworm infection in cats - what are some main differences to dogs
* less prevalent * most worms do not mature * prolonged PPP= 8 mo * no mff * shortened survival * aberrant migration (CNS) * smaller burden can cause disease
88
clinical signs of heartworm in cats
* Heartworm Associated Respiratoy Disease * acute * pulm arteriole hypertrophy * pulmonary edema * tachypnoea * cough * vomiting * weight loss * embolus of dead worms * collapse - death
89
how does heartworm associated respiratory disease (HARD) develop in cats
* juvenile worms in pulm a (3 mo) * eosinophilic vasculitis and pneumonitis (pulm edema) * compromise to pulm function (hypoxemia, cough) * worms mature to adults * asymptomatic or cough, dyspnea, vomit, neurologic * death, embolisation * acute resp distress, death
90
When can you perform the antibody test for heartworm in cats? What other diagnositics?
* as early as 8 wks post infection * need at least \>1 female adult * radiographs * echocardiogram * parallel lines -echogenic cuticle of worm within main or right lobar pulm a. * lung lavage * rule out Aelurostrongylus * trial on moxidectin
91
How do you treat heartworm in cats?
* prednisolone * sx * \*\*\*\*adultacides contraindicated
92
What are features of male and female enoplids?
* male * single spicule or no spicule (trichinella) * female * oviparous (thick lemon shaped eggs- bipolar plugs) * viviparous L1= infective stage
93
What kind of nematode?
enoplids * trichinella * food borne zoonosis * trichuris (whipworm) * humans, dogs, pigs * capillaria (hairworm) * poultry
94
How do humans get Trichinellosis?
* ingestion of undercooked meat * domestic pigs \> T. spiralis (typically encysted) * hunted game meat * feral pig, cougar, bear, croc
95
Is trichinella present in australia?
no - or unreported (only present in tasmania)
96
What is the life cycle of trichinella?
domestic cycle * eat scraps * larvae travel to muscle and encycst sylvatic cycle * predation/scavenge DH1 = ingestion L1 \> SI moult to adult \> L1 enter circultaion \> muscles (encyst) \> DH2 ingest L1 encysted mm \> SI to adult \> circulation \> L1 in mm
97
What are the 2 groups of trichinella sp?
encapsulated * mammals only * L1 surrounded by collagen capsule and "nurse cell" within muscle tissue * no inflam response non-encapsulated * mammals, birds, reptiles and marsupials * L1 free in muscle tissue
98
What species of trichinella? encapsulated or not? What is the primary host and distribution?
Top * T. spiralis * domestic pigs * encapsulated * temperate and tropical regions (not AU) Bottom * T. pseudospiralis * tassie devils * non encapsulated * tasmania
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What are the clinical signs of Trichinellosis?
Animals: NONE Humans * per acute - intestinal phase (L1) * dxa, abdo pain, vomit, fever * acute (muscle invasion): 2-8 wks * eosinophilia- elevated CK * myalgia * vasculitits, cardiac/neuro complications \> death
100
How do you kill trichinella spp? Diagnose?
Treat: corticosteroids and albendazole to kill L1 Diagnose: serology, biopsy, PCR, histo with meat inspection
101
Why does poverty lead to increased rates of trichinellosis?
* cannot afford to feed pigs\> roam and scavenge * backyard slaughter * lack of meat inspection * smoked rather than properly cooked meat
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When prevention and control practices can reduce cases of trichinellosis?
* proper animal husbandry * prevent scavenging * certificate of trichinella-free produciton * meat preparation * cook over 77 C * meat inspection and certification * freezing * -20C for 2 weeks - T.spiralis * all exported farmed pork freeze certified * testing: artifical digestion methods and visualise larvae * look for encapsulated and unencapsulated forms * 5g of diaphragm from "high risk" meat
103
What is significant about this egg?
Trichuris spp. * eggs take 3 weeks to embryonate * eggs highly resistant (4-5 yrs in environment)
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general life cycle of Trichuris spp? (whipworm)
ingest egg with L3 \> larvae hatch in SI \> bury schistosome in mucosa of cecum- feed on tissues and interstitial fluid \> unembryonated eggs released in feces PPP= 10-12 wks
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What host does each Trichuris species belong to? 1. T. trichura 2. T. vulpis 3. T. suis 4. T. campanula, T serrata 5. T. discolor, T. globulosa 6. T. ovis, T skrjabini
1. T. trichura \> human +++ 2. T. vulpis \> dog +++ 3. T. suis \> pig ++ 4. T. campanula, T serrata \> cats + 5. T. discolor, T. globulosa \> cattle + 6. T. ovis, T skrjabini \> sheep +
106
With a heavy load of Trichuris spp (especialy humans, dogs and pigs) what clinical signs do you expect?
* congestion, submucosal edema, necrosis, fibrosis * watery and mucoid dxa, frank blood * tenesmus * rectal prolapse
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A dog presents with hyponatremia and hyperkalemia (similar to addisons disease)...what nematode causes this?
Trichuris vulpis
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How do you treat a whipworm infection?
* oxantel & MLs & BZs * with pyranel pamoate salts fecal oral control important \> hygiene and lower stocking density
109
What are 2 main hairworms that are pathogenic in poutry? What are their predilection sites?
* Capillaria annulata : crop * Capillaria caudinflata : SI
110
What is the behaviour of Capillaria eggs in the environment?
they embryonate in soil or in earthworms - eggs look like trichuris spp.
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Clinical signs of light vs heavy infection with Capillaria spp in chickens?
light * poor weight gain, production loss heavy * catarrhal thickening, diptheritic inflammation of esophagus or crop * hemorrhagic enteritis * high mortality
112
What are the main features of acanthoceohala? (thorny headed worms)
* dioecious (male and female) * cylindrical and large * proboscis with hooks and spines (pathogenic effect) * no digestive tract
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General life cycle of acanthoceohalans?
* eggs shed in feces (eggs live for a long time) * eggs ingested by intermediate host * Arthropod IH: dung beetle, cockroach etc * acanthor\> cystacanth * cystacanth stage ingested by definitive host * proboscis jams into intestinal wall (SI)
114
What is the acanthoceohalan of pigs and how do you treat?
Macracanthorhynchus hirudinaceus * absorb nutrients along the body * clinical signs : malnourishment, granuloma at site of attachment, enteritis +/- perforation * \*\*\* egg can look like a nematode egg- ciliated larva inside Treat: ivermectin, **levamisole,** BZs
115
What is the acanthoceohalan of cats and dogs?
Oncinola spp * common in SI of feral or stray cats/dogs * usually asymptomatic +/- enteritis
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Parasitology (5 decks)

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