Block 3 Flashcards
Definitive Host (DH)
a host in which the parasite develops to mature stage
Intermediate Host (IH)
a host in which a parasite develops to the infective stage of the DH
Paratenic Host (PH)
a host not necessary for the development of the parasite (enhances the chance that the parasite life cycle will be complete)
• biological vector
o host in which a protozoan parasite develops through either asexual or sexual multiplication
o transmits parasite via
mouth parts after biting a DH
feces deposited on DH as it is feeding
Infection
when endoparasites infect the host INTERNALLY
infestation
when ectoparasites attach to OR occupy the host
Self-limiting Infections
Development of species or strain specific immunity
- Parasite is eliminated
- Protection from subsequent infection
Prepatent Period (PPP)
Time from infection to when eggs, cysts, and larvae appear in body fluids or excretions from the DH.
Spirocerca lupi
o esophageal worm
o FH: dogs, wolves, lions, (L3); IH: dung beetles (egg with L1) ; PH: chickens, birds and lizards
o Site: stomach to esophagus, migrating though the thoracic aorta possibly leaving lesions.
o Size: adults, pink/red 8cm. eggs small+elongated 30-35 um
Toxocara canis
o common: roundworm, ascarid
o FH: dogs ZOONOSIS ; PH: rodents
o Modes of infection: per os (eggs L2), transmammary (L3), transplacental (prenatal)(L3)
o Site: Small intestine
o Size: large white 10-15cm. eggs dark brown, round 85x75 um
Toxocara cati
o common name: common round worm/ascarid
o FH: cats PH: rodents
o Modes of infection: transmammary, per os (egg L2), paretenic hosts.
o Site: small intestine
o Size: large, white 4-10cm. eggs 60x80um round and thick shelled
Toxascaris leonia
). Eggs reach infective stage in about a week. Eggs hatch in the stomach and L enter the mucosa of small intestine (develop and molt then return to lumen of the intestine to mature). If eggs are ingested by rodents, they hatch and encyst as infective arrested larva (no placental or mammary gland transmission. Prepatent period is 2-21/2 months!
Ancylostoma caninum
o common name: hookworm
o FH: dogs, foxes; PH:rodents
o modes of infection: percutaneous, per os, paratenic hosts, transplacental, transmammary. (L3)
o Site: small intestine
Diphyllobothrium and Spirpmetra (Diphyllobthriidae)
- Copepods as first intermediate host
- Dog eats fish, amphibian, or reptile as a second intermediate host
- Eggs contain first stage larva = Oncosphere
- Second larva = Proceroid, in the body cavity or tissue of the first intermediate host.
- Third larva = Plerocercoid, in the second intermediate host
- Definitive Host = ingested the plerocercoids (aquatic food chain)
- - Most digested but left the scolex and the neck
Treatment: Praziquantel
Taenia Identification
- 10-100 cm in length
- Non-retractable rostellum with two rows of hooks (hooks use for firm attachment in theDigestive Tract
- Rectangular segments
Taenia Life Cycle
- Definitive Host = Gravid segments
- Eggs = Onchospheres,
- Ingestion of the intermediate host, the eggs hatch to give hexacanth embryo (spines on the surface)
- Hexacanth embryo migrates to the liver and both of the skeletal and cardiac muscle
- Second-stage larva infective to the definitive host (must eat the immediate host/rabbits)
- Scolex attaches to the small intestine and begins to bud off segments
- Second stage larva (found in the intermediate host) can include:
1. Cysticerus (Single bladder with one scolices, T. hydratigena)
2. Strobilocercus (elongated segment in the intermediate host, infection of a long time, T. taeniaformis = feline)
3. Coenurus (Single bladder with many scolices, T. serialis)
4. Hydatid (Formed by Echinococcus it can be either unilocular or alveolar) - Cysts (juvenile) is more infective stage than adults
Taenia hydratigena
Mammal host needed for the intermediate host of Cysticercosis. Taenia hydratigena (canine), the infective stage is the cysticercus migrates through the liver and encysts
Traumatic hepatitis
(condemnation of infected livers by meat inspectors)
Taenia ovis
Canine, Cysticerus infects the cardiac and skeletal muscles of sheep
Taenia pisiformis
Cysticerus is found in the liver and the peritoneal cavity of rabbits
Taenia saginata
Human, cysticerus found in the striated muscles of cattle, no hooks Eating beef, because it has no hooks, the human being cannot act like intermediate host)
Taenia solium
Human, people become infected by eating undercooked pork containing cysticerci (containing ones’ fingers with the infected feces)
Person feces containing eggs that can reach the mouth (lapse in personal hygiene)
Taenia taeniaformis
Strobilocercus larva of the cat (definitive host)
Taenia multiceps:
Sheep, goats, cattle causes coenurosis (intermediate host because of present of conurosis)
Cysts invade cranial cavity
Neurological Signs (Blindness, incoordination, walking in circles)
Many canids (definitive host)
Taenia serialis:
Dogs and Foxes (intermediate host)
Echinococcus Granulosus
Identification
Identification:
- 45 to 65 testes and genital pore is located at or posterior to the middle of the segment
- Parasite of the Dog, coyot, wolf and dingo
Echinococcus Granulosus
Life Cycle
Larva = hydatid Cyst (Sheep, swine, cattle, humans, moose, caribou, kangaroos)
- Hydatid = Sheep, fertile (intermediate host)
- Hydatid = Cattle, Sterile (intermediate host)
- Echinococcus granulosus granulosus: Sheep and human (most effected)
- Echinococcus granulosus equinus: Horses, Donkeys, and Mules (intermediate host
Echinococcus Granulosus
Distribution
Endemic in North and South America, England, Africa, and Middle East
- Non-infiltrative, non-fatal, small in cattle, massive in humans, Unilocular or alveolar
Echonococcus multilocularis
Identification
17-26 testes,
- Endemic north central Europe, Alaska, Canada, and central United States
Echonococcus multilocularis
Disease
Pressure atrophy of surrounding organs
- Allergic reactions to fluid leaks
- Hydratidosis
- Unilocular hydrated cysts is the second stage larva of Echinococcus granulosus and is infective to dogs and other canids (definitive). Starting as an onchosphere, the larva grows slowly. As humans live longer, fertile hydatid may grow very large
Echonococcus multilocularis
Life Cycle
Alveolar Hydatid Cysts:
- Second stage larva of E. Multilocularis (infective to dogs, foxes, and cats, which serve as a definitive host)
- Develop in voles, lemmings, cattle, horses, swine, and humans
- Fatal and Infiltrative
- Contamination of pastures results in domestic ruminants and swine infections
- Pastoral Cycle results from feeding uncooked meat to dogs and cats
Pastoral and Sylvatic
Pastoral and Sylvatic of E. granulosus and E. Multilocularis: Sylvatic cycles (Predator-Prey), reaches human through their domesticated animals. E. granulosus cycles are maintained in wild ruminants and wolves (Canada); Wallaboes and dingoes
Echonococcus
Control
Rid of stray Dogs
- Anthelminitic Medication - Prohibition against feeding uncooked OFFAL to dogs and cats
Echonococcus
Treatment
- Benzimidazole carbamate derivatives
- Mebendazole and albendazole are currently used for chemotherapeutic treatment of Alveolar Echinococcus, as well as of cystic hydatid disease
- The only curative treatment of AE is still radical surgical resection of the parasite tumor, supported by pre and post-operative chemotherapy
Moniezia
Identifcation
- Looks like broken glass, if in dog don’t treat, he ate poo
- Unarmed Scolices
- Four Suckers
- Very wide segments with bilateral genitalia
- Characteristic egg shaped (triangle in shaped)
Moniezia
Transmission
Oribatid Mites
Moniezia
Life Cycle
In small intestine of cattle, sheep, and goats
- Involve arthropod (oribatid mites and Psocopterans lice) as intermediate host (cysticercoid). Ingestion of infected arthropods results in infection of grazing animals
Dipylidium caninum, Diplopylidum spp., Joyeuxiella
Identification
4 Suckers
- Retractable rostellum (thorn-like hooks)
- Segment looks like cucumber seeds
- Bilateral genital pores
Dipylidium caninum, Diplopylidum spp., Joyeuxiella
Life Cycle
Cysticercoids (infective stage) develop in fleas (Ctenocephalides spp.) and biting lice (Trichodectes canis)
- Onchospheres (fully developed embryo) are ingested by the flea larva
- After emergence of adult flea, hexacanth develops into cysticeroid
- Onchospheres (fully developed embryo) are ingested by self grooming
- Adult worms develops in the small intestine
- Diplopylidium and Joyexiella develops in the Beetle, Reptiles and small mammals serve as a second intermediate host (paratentic host)
Hymenolepis diminuta
Identification
In Rodents and Sometime in dogs or humans
- No hooks - Three testes and a single ovary
Vampirolepis nana
Identification
Rodents and Humans
- Fleas and flour beets are intermediate host (cysticercoid) - Single circle of hooks - The cysticercoid can be found in the intestinal mucosa of the definitive host - Three testes and a single ovary - Interal-organisms infection (copies itself with the host)
Mesocestoididae corti
Identification:
- 4 suckers - No hooks - Mediodorsal genital pore - Eggs accumulate in paruterine organ
Life Cycle:
- Infective stage for definitive host is tetrathyridium (Peritoneal cavity) - Arthropods intermediate host (cysticercoid)
Nematoda
Identification
Constant body form
- Large body cavity (pseudocoelom) - Inelastic cuticle and pseudocoelom fluid enable the worm to maintain constant body diameter - Special way of movement (no circular muscle layer) - Cuticle is permeable to both water and gases (respiration) - Mouth with 3 lips (may have teeth) Pharynx Intestine - Feces expelled under pressure - No circulatory or respiratory organs - Muscular esophagus - Males are smaller than the female - Female reproductive system can be monodelphic, didelphic (two branches) , or multidelphic
Nematoda
Life History
Morula (one cell) and vermiform (i.e. microfilaria) embryo are important in diagnosis
Order Strongylida Superfamilies
- Strongloidea
- Trychostrongyloidea
- Ancylostomatoidea
- Metestronglyloida
Strongyloidea
Identification
- Well-developed buccal capsules (may or may not have teeth)
- Stoma
- Male nematodes of the order Strongylida have a caudal copulatory bursa, dorsal, lateral and ventral expansions of the cuticle (lobes), supported by muscular processes (rays)
- The disposition and configuration of these rays are used in classification and identifcation of Strongyloids
- Have dorsal and lateral lobes of equal size, thin, and flexible spicules
Strongyloidea
Life Cycle
- Free-living microbivorous first and second larval stages
- Eggs contain morula stage when deposited and passed put with feces
- Morula develops into first stage larva which gives second stage larva (still in feces; feed on bacteria)
- Second stage larva undergo second molt to give a third-stage larva that continue to keep the cuticle of the second larva until entering a suitable
- Third Stage larva begin to mirgrate out the fecal mass to be ingested by the grazing animal
Strongyloidea
Control and Treatment
Separate ill animals (anemia, diarrhea, weakness)
Anthelmintic may fasten the death of very sick animals
Trychostrongyloidea
Identification
Small buccal capsule which may be equipped with a tooth or lancet in blood sucking species
Common and pathogenic in grazing ruminants (abomasum and small intestine)
Trichostrongylus: Hairlike, no capsule, short spicules
Trychostrongyloidea
Life Cycle
Free-living microbivorous first and second larval stages.
Eggs contain morula stage when deposited and passed out with feces
Morula develops into first stage larva which gives second stage larva (still in feces; feed on bacteria)
Second stage larva undergo second molt to give a third-stage larva that continue to keep the cuticle of the second larva until entering a suitable
Third Stage larva begin to mirgrate out the fecal mass to be ingested by the grazing animal
Trychostrongyloidea
Disease
- Infective third stage larva survive the winter on pasture
- Ruminants are exposed to infection in spring
- All larvae die off in summer
- Eggs laying continue over the fall to give the new winter generation of larvae
Trychostrongyloidea
Specie
Trichostrongylus axei: parasite of stomach (abomasum) or ruminants , horses, and leporids
Amidpstromum: parasite of geese and ducks (but not mammals) has large toothed buccal capsule)
Ostertagia ostertagi
1. Cattle (Floatation Diagnosis)
2. Chronic Abomasitis
3. Most serious helminth parasite of cattle in the USA
Teladorsagia cirumcincta
1. Sheep and goat
Haeminchus
Identification
Buccal cavity armed with lancet
Asymmetrical dorsal ray and short, wedge-shaped spicules
Haemonchus Disease
Haemonchus contortus
1. Removal of the circulating erythrocytes volume from lambs
Anemia
High egg counts (10,000/gram)
Mecistocirrus
Identification
Parasites of abomasum of ruminants and stomach of pigs in Central America
Suck blood and produces anemia and diarrhea
Cooperia
Buccal cavity is very small, the spicules are short and blunted at their tops
Confused with Trichostrongylus
Accumulation of feces result in foul condition that attract blowflies (resulting in myiasis) on sheep sm intestine
Nematodirus
Identification
Triangular tooth
Female has a spine at the tip of tail
Infect domestic ruminants
Nematodirus
Life Cycle
Larva develops to the infective third stage within the egg shell
Hatching depends on extrinsic stimuli (weather change)
Nematodirus
Disease
Neatodirus battus causes severe and debilitating diarrhea in lamb
Hystrongylus rubidus
Stomach of swine
Larva invade the gastric glands
Causes gastritis
Ollulamus trcuspos
Ovoviviparous
larvae mature in the stomach (single host, very rare)
Transmitted by ingestion of vomitus from an infected host
Causes chronic gastritis in cats (fatal)
Dictyocaulus viviparous (Lung worms) Identification
Found in respiratory passages of ruminants and horses
Lumen of the bronchial tree
Cause chronic bronchitis
Only nematode that reaches maturity in the ling of the cattle
Free living stages depends on stored energy
When ingested larva migrates through mesenteric lymph nodes
Dictyocaulus viviparous (Lung worms) Treatment
Rotate pasture
Dictyocaulus arnfieldi:
Pathogenic in horses but tolerated in donkeys
TREATMENT of Trychostrongyloidea
Ruminants:
1. Thiabendazole, 2. Fenbendazole 3. Albendazole 4. Ivermectin 5. Dormactin 6. Livamisole 7. Mornatel
Stronglyoidea
Identification
Large buccal cavity surrounded by a buccal capsule
Well developed copulatory bursa
Prodelphic vulva (caudal end) is common
Strongylinae “Large stronglyes”
Identification
The most destructive parasites of the horse are: (all three are blood suckers as adult worms in the cecum and colon) (larvae needed to differenciate between the three species)
1. Strongylus vulgaris 2. Strongylus edentates 3. Strongulus equinus
Strongylus vulgaris
Life Cycle
Larvae undergo migrations that cause great damage
Infective larvae can resist cold weather and desiccation
The third stage infective larvae enter the wall of the cecum and ventral colon upon ingested a horse (MORE MIGRATION Larvae)
Fourth larvae penetrate the colic and cranial mesenteric arteries
Strongylus vulgaris
Pathogenicity
Larval migrations damage the cranial mesenteric artery and its branches
Strongylus Treatment
Ivermectin and Albendazole
Strongylus edentates and Strongylus equinus
Adults are twice as large as S. vulgaris
Adults are more pathogenic and more difficult to treat
Third stage larvae of S. edentates reach the liver through the portal veins, molt in the hepatic parenchyma
The third stage larvae S. equinus molt in the wall of the cecum
Fourth stage larvae reaches the right half of the liver, enter the pancreas or abdominal cavity, adults enter intestinal lumen
Cyanthostominae
Identification
Small strongyles
Small buccal cavity
Distinct inner and outer lead crowns
Common in horses
Cyanthostominae
Disease
Arrested larvae in large number cause disease = Cylicocyclus insigne
Cyanthostominae
Treatment
Not affected by treatment (arrested larvae); dexamethasome (adults)
Treatment Cyanthostominae
Let horses exercise in no grass areas (no contamination)
- Periodic anthelmintic 3 Benzimidazole
- Piperazines
- Febantel
- Ivermentin
- Fenbendazole
- Selective Treatment: method for avoiding the development of resistance
Oesophagostominae
Identification
Parasites of large intestine of ruminants, wine and primates
Known as NODULAR WORMS
Calcified nodules interfere with the intestine function
Oesophagostominae
Diseases
Oesophagostomum columbianum
2. Chabetria ovina 3. Oseophagostomum radiatum
Stephanures dentatus
Identification
The Kideny worm of swine (females form cysts in the kidney fat)
Parasite of hepatic, renal, and perirenal tissue
Cup shaped buccal cavity
Stephanures dentatus and Cyathostoma: Earthworm serve as intermediate host (facultative become a must)
Stephanures dentatus
Infection
Direct Ingestion
Indirect Ingestion
Penetration of third-stage larvae
Stephanures Dentatus
Disease
Liver Damage
Staphanus Dentatus
Treatment
Fenbendazole
Ivermectin
Parasites of upper respiratory tract. EW serves as IH
Syngamus and Cyathostoma = birds
mammonogamus - mammals
Ancylostomatidae (Hookworms)
Identification
Parasite of the small intestine Anterior end of the worm is “hooked” Ancylostomatinae parasitize carnivorous hosts Bumostominae parasitize herbivorous Omnivorous are parasitized by both
Ancylostomatidae (Hookworms)
Life Cycle
Free living microbivorous first and second larval stages
Eggs contain morula when deposited and passed out with feces
Third stage larva begin to migrate out the fecal mass to be ingested by the grazing animals
Ancylostomatidae (Hookworms)
Species
Ancylostoma braziliense: one pair of teeth (Dogs)
Ancylostoma duodenal: two pairs of teeth (Human)
A. tubaeforme: three pairs of teeth (cat)
A Caninum: three pairs of teeth (Dogs)
Globocephalus urosubulatis: No teeth, no plates (Swine)
Placoonus lotoris: Five articulating plate (Raccoons)
Bunostomum: Ruminants
Bathmostomum: Elephants
Grammocephalus: Elephants and rhinoceroses
Necator: Human
A. Caninum Characteristics
(sharp teeth and more pathogenic)
A. Caninum Life Cycle
Infection occurs through ingestion or penetration
Arrested larvae later becomes active to either mature into adults (intestine) or shed from mammary glands (pups infection) and placenta
A. Caninum Diseased
A. caninum is more pathogenic
Kennel and Pet shops accumulation of feces
Peracute hookworm disease: larvae passed through milk to pups
Acute hookworm disease:
1. Exposure of older pups to large numbers of infective larvae
Chronic hookworm: Asymptomatic (cont. transmission)
A. Caninum Treatment
Creeping eruption
Caused by migrating L in human
Blood Transfusion
Metastrongyloidea
Identification
Parasites of the respiratory, vascular, and nervous system of mammals
Required snail or slug intermediate host
Infective stage: develops in the earthworm
Metastrongyloidea
Life Cycle
Metastrongyloidea eggs laid can contain from a single cell embryo
Molluscan or annelid (earthworm) intermediate hose (first to third infective)
Infection occurs through ingestion of the intermediate host
EXCEPTION TO THOS ARE THE FILAROIDES OSLERI AND FILAROIDES HIRTHI (both can directly infect the dogs in the first larval stage)
Metastrongylidae
Metastrongylus (only genus)
- Bronchi and bronchioles of swine
- Trilobed lips flanking the mouth
- Earthworm (paratenic host)
- Not very pathogenic, oviparous
Metastrongylidae
Treatment
Fenbendazole
2. Ivermectin
Protrongylidae:
Identification
Parasite of sheep and goats
Eggs deposited in lung, vascular or neural tissues, egg develop into L1 before feces
Protostrongylus rufescens (Sheep)
Live in the smaller bronchioles
Comb like spicules
Treatment: Fenbendazole
Muellerius Capillaris
Tiny, deeply embedded in lung tissue or reactive nodules
Moxidatin (Sheeps): heavy infection)
Eprinomectin (Goats): (Heavy Infection)
Parelaphostrongulus tenuis
Parasite of the meninges of the white-tailed deer (Odocoileus virginianus)
Abnormal hosts (sheep, goats, camel, moose) tends to invade nervous system
Crenosoma vulpis
In the bronchi and bronchioles of foxes, raccoons, and dogs
Troglostrongylus
Felidae
Aelurostrongylus abstrusus
Identification
Lung parenchyma in cats
Eggs are deposited in “nests” (oviparous) that appears as nodules
Symptoms: Coughing, anorexia, dyspnea, and polynea, many remain free of clinical signs
Aelurostrongylus abstrusus
Treatment
Ivermectin
2. Selamectin 3. Fenbendazole: Paralysis, treatment can kill host
Angiostrongylous Vasorum:
Pulmonary arterial tree of dogs
Disease: Pulmonary Thrombosis and interference with clotting leading to multiple subcutaneous hemorrhages
: Angiostrongylus cantonensis
Lingworm of the rat
Causes eosinophilic meningitis and encephalomyelitis in humans (eating infected raw snails, slugs)
Filaroides osleri and F. hirthi
Occur in nodules within the epithelium of the trachea and bronchi or w/n the lung parenchyma
Ovoviviparous directly infectiveaL1 larva
No intermediate host
Filaroides osleri and F. hirthi
Signs and Treatment
▪ F hirthi: normally no clinical signs; fatal in severely stressed and immunodeficient animals
▪ F. osleri: Dry cough, chronic disease
▪ F. hirthi :Albendazole, ivermectin
▪ F. osleri: Thiacetarsemide injection, Thiabendzole, fenbendazole, ivermectin; no satisfactory treatment
▪ Filaroides hirthi (reaction to dead and dying worms); Filaroides osleri (right) nodules near tracheal bifurcation
Rhabditida
Identification
Small nematodes
Parasites of lower vertebrates or invertebrates
Rhabditis, Halicephalobus, and Strongyloides parasitize domestic animals
Rhabditis (Pelodera) strongyloides:
Identification
Produce a pruritic, hyperemic dermatitis in cattle, swine, dog, horses and rodents
(Damp straw bedding causes dermatitis in canine that caused by this parasite)
Halicephalobus (Micronema) Deletrix:
Identification
Rhabtitoid esophagus ; only one egg in uterus
Highly pathogenic parasite of horse and man
Equine
Fatal in humans
Strongyloides
Identification
Name mean round and compact
Female lies deep in the mucosal crypts of the alimentary tract (sm. Intestine)
Strongyloides stercoralis
Humans dogs and cats
S. papillosus
Ruminates
Life Cycle of Strongyloides:
Parasitic male do not exist
Parasitic females have no male gonads
Homogonic Rhabditiform: larvae in the external environment develop through two molts into infective filariform larvae or through four molts into free-living males and females
Filariform larvae penetrate the skin of suitable host, molt twice to give parasitic female
S. ransomi
Swine
S. westeri
horses
S. fuelleborni
African primates and humans
S. cebus
American primates
S. ratti and S. venezuelensis
Rats
Diseased caused by Stronglyloides
Asymptomatic in most domestic specie
Anemia in Piglets, Diarrhea in fouls
Bronchoneumonia, diarrhea, hemorrhage
Control of Strongyloides
Cages and pens must be cleaned
Separate pups immediately after birth
Suitable anthelminitic
Oxyuris equi
Pinworm
Highly specific parasite of the larger intestines
Oxyuris Equi
Diagnosis
Cellophane tape against the anus and then stick it to a slide
Disposable cloth to clean perineum of the horse
Oxyuris Equi
Treatment
Ivermectin
Pyrantl tartrate
Ascaridida
Identification
Intestinal tract of domestic animals
Most common of all nematodes
Infective stage of development take place inside the egg
Parasitize aquatic vertebrates (have free-swimming larval stages and intermediate host)
Ascaridida
Two types
Terrestrial
Aquatic
Ascaris Suum
Identification
Eggs hatch in the stomach and small intestine to give infective L3 which enter the wall of the cecum and colon and proceeds to the liver through the portal vein
Larvae out into the alveoli, reach the pharynx to be swallowed (mature in the intestine) how pigs gat a. sum
Ascaris suum
Disease
Migration cause mechanical damage and allergic inflammation (eosinophilic inflammation)
Milk spot (fibrosis of the liver)
Condemnation
Pigs: Server respiratory problems
Ascaris Suum
Treatment
Pyrantel tartrate can kill infective larva
Fenbendazole
Ivermectin
Piperazines
Parscaries equorom
Identification
Found in horse
Liver and lung damage results in chronic reduction
Parascaries equorom
Results
Malnourished
Parascaries equorom
Treatment
Paralysis the worms may cause obstruction of the bowel
Difficult to destroy eggs
Pyrantel tartrate
Somatic migration
Toxascaris leonine
Identification
Parasite of dogs and cats (cool climate)
No placental or mammary gland transmission
Toxocara canis
Identification
Canine (CNS invasion)(intermediate host)
Toxocara canis
Life Cycle
Larvae that undergo tracheal (newborn puppy) migration develop to sexual maturity
Somatic migration results in arrested lavae
Placenta and mammary glands transmissions
Tracheal ends in mature worms
Pups can be born with infection
Arrested larvae “encysted” in paratenic host
More pathogenic than Leonia in definitive host
Toxocara canis
Control of Canine and Feline Ascarid Infection
Sanitation
Clean all surfaces
Keep in dogs and cats indoor
Toxocara canis
Treatment
Piperazine
Fenbendazole
Cesarean section of cats
No placental transmission
Human Toxocarosis (Visceral larva migrans) (T. Canis):
Nodules in liver, lungs, kidneys, and brain
Larvae may cause granulomatous retinitis
Eating contaminated Soil
T. Cati
less important as a cause of visceral larva migrans
Baylisascaris spp
Identification
Common in North American wildlife
CNS invasion
: Baylisascaris procynoins of the raccon
B. Columnaris of the skunk
Raccoons can be treated using anthelmintics active against T. Canis: 5 eggs
cause death in humans
Baylisascaris procyonois
Causes human visceral larva migrans
Larvae grow as they migrate
Camallanina (Dracunculus) and Spirurina
Identification
Require either an insect or crustacean intermediate host to develop into infective stage
Definitive host become infected through ingestion of intermediate host or paratentic
host
Dracunculus
Identification
Guinea worm
Parasite of subcutaneous tissue of carnivorans and man
Dracunculus
Life Cycle
Indirect
Larvae discharged into the water and when ingested by Cyclops (copepod) develop into infective stage
Definitive host infective by drinking water
Dracunculus insignis
raccoons, dogs, cats in North America
Frogs as paratenic host
TX: winding the worm up on a stick
Dracunculus medinensis
Man in the Middle east
Spirurina
Identification
Six superfamilies which are parasite of domestic animals
2. Characterisitcs stoma and surrounding structures
Gnathostomatoidea
Doughnut-shaped collar of spines around the oral openings
Adults are found in cystic nodules
Amphibins, snakes, and fishes as parantenic host
Cystic nodules may break open into peritoneal cavity (severe inflammation called
peritonitis, fatal)
May migrate to the brain
Tx: unknown
Physalopteroida
Parasite of the stomach of carnivorans (stomach worm)
Adults live in the stomach with the anterior end embedded in the muscosa
Eggs are passed in the feces. The eggs, which contain larvae, are ingested in the
beetles
Cause bleeding in the stomach
Thelaziidae
Parasites of conjunctival and lacrimal sacs of domestic animals (Eye worm)
- - North American specie: Thelazia caiforniensis - - These larvae develop into infective larvae in the face fly (Musca autumnalis)
Spiruroidea: Gongylonema
Mucous membrane of the host esophagus (G. pulchrum) or rumen (G. verrucosum)
Infective: in dung beetle or cockroach
Spirocera lupi
Found in nodules in the esophagus wall or stomach
Eggs contin vermiform larvae/embryo
Disease:
Dysphagia and vomiting
Habronematoidea
Parasite of the equine stomach
If deposited in wounds will not complete the life cycle: Results in cutaneous
granulomas
Dirofilaria immittis (dog heartworm) Life Cycle
– Transmitted by blood sucking insects where microfilaria develop into infective
L3
– Microfilaria circulate in the blood
– Adults are found in the pulmonary arteris
– Dead worms are carried deeper into the lungs
– Mosquitoes as vector
Dirofilaria immittis (dog heartworm) Disease
- Illness start with the appearance of microf. In blood with physical obstruction of vessels, heart chambres, and valves
- - Pulmonary hypertensions and right heart failure
- - Dogs appears fatigue, cough,
- Illness start with the appearance of microf. In blood with physical obstruction of vessels, heart chambres, and valves
Dirofilaria immittis (dog heartworm) Diagnosis
Microfilariae in blood (Dipetalonema reconditum)
Dirofilaria immittis (dog heartworm) Control and Treatment
- Ivermection and Milbemycin oxime
- Prevention of Macrocylic lactone
- Heartworm disease in cats. When dealing with cat infection, be aware that cats carry very few worms amicrofilaramic, no enough circulating antigens.
Setaria labiatoppilloa and S. equine
parasites of the serous membranes of cattle and horses
Migrating L may invade CNS causing neurological disease
Adults found moving in the horse eye anterior chamber
Onchocerca spp
Black Flies
TX: Ivermectin
Onchocerca cervicalis
Found in the nuchal ligament of the horse
Onchocera. gutterosa
in cattle I nuchal ligament (connective tissue)
Onchocera. linalis
connective tissue between the spleen and the rumen of cattle
Parafilaria multipapillosa and Parafilaria bovicola
Horses and cattle respectively
Subcutaneous and inter-muscular connective tissues causing bleeding from nodule through a tiny pore (Summer Bleeding)
Horses bleed when under sunlight
Dipetalonema reconditum
Canine
Hooked on end
arised from Drofilarie immitis (HW)
Elaophara schneideri
Deer, elk, and sheep
Carotid, iliac, and mesenteric arteries
Tabanids
Elaeophara schneideri
Cattle
Horn fly (Haemotobia irritans) ventral midline dermatitis
Dioctophyme renale
Giant Kidney worm”
Min are principle definitive host
Brownish, thick-shelled eggs,
Bell shapes, eggs passes in urine
Eggs are infective to obligovhate annelid worms
Oligochates are ingested by fish or frogs
Stichosome esophagus
Capillary tube surrounded by glands (Stichocyte)
Trichinella spiralis:
embedded in the mucosa of the small intestine of swine, carnivorans, and man
Found in the cysts in the striated muscle
Both sexes reach maturity within two days of eating infected meat
Host digestive enzymes liberate L from cysts
Raw or undercooked pork: Human infection
Treatment: Albendazole
Trichuris (Whip-shaped)
embedded in the large intestine
lemon shaped eggs
free in the lumen
Trichuris suis
in young cause diarrhea, anorexia and retardation of growth
Control: Separating animals from eggs
Trichuris vulpis
Treated with Fenbendazole (Panacur)
