Ross Parasitology Lifecycle
Order by
143 terms
Latin | English |
|---|---|
| Spirocerca lupi |  Indirect L3 via dung beetle |
| Physaloptera | Indirect L3 via cockroach |
| Toxacara canis | Direct L2 in egg |
| Toxacara cati | Direct L2 in egg |
| Toxascaris leonina | Direct L2 in egg |
| Ancylostoma caninum | Direct L3 |
| Ancylostoma tubaeforme | Direct L3 |
| Ancylostoma braziliense | Direct L3 |
| Uncinaria stenocephala | Direct L3 |
| Strongyloides stercoralis | Direct L3 |
| Trichuris vulpis | Direct L1 in egg |
| Capillaria | Direct or Indirect L1 in egg |
| Oslerus osleri | Direct L1 |
| Aelurostrongylus abstrusus | Indirect L3 via snail or slug |
| Dirofilaria immitis | Indirect L3 via mosquito |
| Dipylidium caninum | Indirect by cysticercoid via flea or louse |
| Echinococcus granulosus | Indirect by hydatid cyst via herbivore |
| Echinococcus multilocularis | Indirect by alveolar hydatid cyst via cattle/equid/swine/rodent/occasional human |
| Taenia crassiceps | Indirect by cysticercus via small rodent |
| Taenia pisiformis | Indirect by cysticercus via rabbit |
| Taenia taeniaeformis | Indirect by strobilicercus via mice/rat/occasional human |
| Diphylobothrium latum | Indirect by plerocercoid via copepod crustacean (1st IH) and freshwater fish (2nd IH) |
| Spirometra | Indirect by plerocercoid via copepod crustacean (1st IH) and any other vertebrate except fish (2nd IH) |
| Alaria | Indirect by mesocercariae via snail (1st IH) and frog/snake/mice/rat/bird/occasional human (2nd IH) |
| Nanophyetus salmincola | Indirect by metacercariae via snail (1st IH) and fish (2nd IH) |
| Paragonimus kellicoti | Indirect by metacercariae via snail (1st IH) and crayfish (2nd IH) |
| Platynosomum fastosum | Indirect by metavercariae via snail (1st IH) and crustacean (2nd IH) and lizard/toad/gecko/skink (OBLIGATE PARATENIC) |
| Cuterebra | Direct L1, develop to L3 subcutaneously and drop off in soil to pupate |
| Trichodectes canis | Direct, entire life cycle occurs on the host |
| Linognathus setosus | egg/nit - 3 nymphal stages - adult. adult can only live off host for a few hours |
| Ctenocephalides | egg - 3 larval stages - pupa - adult. pupa can survive 30 weeks |
| Ixodes | 3 host tick. egg - larva - nymph - adult. drop off to molt |
| Dermacentor | 3 host tick. egg - larva - nymph - adult. drop off to molt |
| Rhipicephalus sanguineus | 3 host tick. egg - larva - nymph - adult. drop off to molt |
| Sarcoptes scabiei | Direct, entire life cycle occurs on the host |
| Demodex canis | Direct, entire life cycle occurs on the host |
| Otodectes cynotis | Direct, entire life cycle occurs on the host |
| Cheyletiella yasguri | Direct, egg - larva - nymph - adult, survive off host longer than other mites |
| Giardia intestinalis | trophozoites undergo asexual repro/budding and encysts. cyst passes in feces and is the infective stage. can survive outside host for 2-4 weeks. |
| Trypanosoma cruzi | reduviid bug releases trypomastigotes in its feces near a bite wound. trypomastigotes invade cells and differentiate into amastigotes. the amastigotes multiply by binary fission and differentiate into trypomastigotes. the new trypomastigotes infect new cells and the cycle repeats. When reduviid bug feeds and ingests trypomastigote it transforms to epimastigote in bugs midgut. the epimastigotes differentiate into metacyclic trypomastigotes in hindgut and are the infective stage. |
| Cystoisospora (Isospora) canis | sporulated oocyst contains 2 sporocysts each with 4 sporozoites, dog eats rodent tissue infected with asexual stage. 1. sporulation - occurs outside host, sporulated oocyst contains 2 sporocysts with 4 sporozoites and is infective stage. 2. infection/schizogony/merogony - sporocyst releases 4 sporozoites, each give rise to a schizont, containing merozoites. they rupture out of small intestinal cell, then invade another cell and form 2nd and 3rd generations. 3. gametogony/oocyst formation - merozoites give rise to male and female gametocytes, macrogametocytes are females, remain unicellular while microgametocytes undergo repeated division to form flagellated uninucleate organisms. fusion results in oocyst, which ruptures out of cell and passes unsporulated in the feces. |
| Toxoplasma gondii | cat becomes infected by ingesting rodent tissues containing tachyzoites or bradyzoites. bradyzoites go through cycle of schizogonous/gametogenous develpment producing oocysts in 3-10 days. Infection of intermediate host occurs by ingestion of sporulated oocyst or ingestion of undercooked meat. |
| Sarcocystis spp. | gametogony in final host and schizogony/sarcocyst formation in intermediate host. final host becomes infected by ingesting muscle with mature sarcocysts containing bradyzoites. the bradyzoites pass to the sub-epithelial lamina propria and differentiate into macro and microgametocytes. they combine and oocysts form. they sporulatre WITHIN the body, two sporocysts each contain 4 sporozoites. intermediate host ingests sporocysts, sporozoites are released, invade intestinal wall and enter capillaries, to endothelial cells where they undergo 2 schizogonous cycles. a 3rd asexual cycle occurs in circulating lymphocytes, resulting merozoites penetrate skeletal muscle cells, encyst/bud/release banana shaped bradyzoites. |
| Hepatozoon spp. | dog ingests infected tick, schizonts occur in various tissues (especially spleen and liver), and invade WBCs. vector ingests WBCs containing gamonts by taking bloodmeal. sexual replication in gut of tick produces oocysts containing sporozoites. |
| Babesia canis | dog inoculated by R. sanguineus, sporozoites enter bloodstream, multiply by schizogony in erythrocytes. these trophozoites can be seen as round, ovoid, elongate, amoeboid, pyriform, or cruciform. host cell ruptures and organisms penetrate new cells. tick takes bloodmeal and ingests infected RBC. schizogony in the tick forms vermicules. |
| Theileria (Cytauxzoon) spp. | poorly understood. cat contracts trophozoites from Dermacentor, may or may not circulate in blood. schizonts found in erythroblasts, WBCs, macrophages and other host cells. schizonts release merozoites which infect RBCs. |
| Draschia megastoma | Indirect, IH is fly, lifecycle flourishes in summer. Fly deposits larvae on horse, adults in stomach pass to dung pat, egg hatches to L1, fly larvae in same dung pat eat L1, nematode larvae molt to L3 in fly pupae. |
| Habronema muscae | Indirect, IH is fly, lifecycle flourishes in summer. Fly deposits larvae on horse, adults in stomach pass to dung pat, egg hatches to L1, fly larvae in same dung pat eat L1, nematode larvae molt to L3 in fly pupae. |
| Habronema majus | Indirect, IH is fly, lifecycle flourishes in summer. Fly deposits larvae on horse, adults in stomach pass to dung pat, egg hatches to L1, fly larvae in same dung pat eat L1, nematode larvae molt to L3 in fly pupae. |
| Parascaris equorum | Direct, eggs survive in environment 23 mo or longer, PPP 2.5 mo. infective stage L2 in egg is swallowed, hatches in intestine, burrows through wall of intestine, liver, lungs, migrates from trachea, swallowed and develop to L3 2-3wk after infection. ONLY per os transmission. |
| Strongyloides westeri | Direct with homogonic and heterogonic phase. in homogonic phase, L1 in egg passed in feces, L1 develops to L3 in soil, L3 penetrate host skin, undergo migration to heart, lungs and up trachea, swallowed and migrate to intestine, develop to adult females only and pathogenesis takes place, infect prenatal or transmammary. PPP about 2 weeks. in heterogonic phase, free living larva develop in soil directly into males and females, and reproduce in soil, infect percutaneous and per os. |
| Strongylus vulgaris | Direct, infective L3 are ingested during grazing, develop to L4 in intestines and migrate to submucosal arteries, migrate against flow of blood to cranial mesenteric and ileocolic arteries, after 3-4 mo. they molt and migrate via arteries back to large intestine, develop to sexually mature adults, copulate and lay eggs, PPP 6mo. |
| Strongylus edentatus | Direct, migration through liver from 9th week and to tissue of abdominal flanks, PPP 11mo. |
| Strongylus equinus | Direct, migration to liver and return to cecum by unknown route, PPP 9mo. |
| Cyathostomins | Direct, L3 ingested during grazing, L2 migrate to and enter large intestinal wall, after 1-2 mo, emerge in intestinal lumen as L4, develop to adults, PPP 1.5-4 mo depending on species. |
| Oxyuris equi | Direct, adults live in dorsal colon, gravid female migrates through anus to lay eggs around perineum, eggs develop to L3 and are ingested, L3 live in crypts of dorsal colon, develop to L4 and adults, PPP 4-5mo. |
| Dictyocaulus arnfieldi | Direct, adult stages in bronchi lay eggs containing L1, which hatch in lungs, pass in feces, eggs develop to L3, migrate on pasture and are ingested, L3 penetrate mucosa of small intestine, enter lymphatics and blood, migrate to lungs, PPP 2-4mo. |
| Setaria equina | Indirect, mff in bloodstream are ingested by mosquitoes, PPP 8-10mo. |
| Ochocerca cervicalis | incoculation of L3 by intermediate host (Culicoides), arrival of parasites in ligamentum nuchae or umbilicus area results in host reaction |
| Anoplocephala perfoliata, Anoplocephala magna | Indirect, mature segments pass in feces and disintegrate, releasing eggs which develop to oncospheres, which are ingested by forage or orbatid mite, develop to cysticercoid, 1-2mo. later, adult tapeworm found in intestine of horse. |
| Gasterophilus intestinalis | eggs deposited on hair of forelegs and shoulder, 1st instar hatches when licked by horse and attaches to tongue, develops to 2nd instar in oral cavity and is swallowed. develop to 3rd instar, live for up to 12 mo. in stomach, pass out with feces in late spring and pupate in soil, adults emerge 3-9 wks later. |
| Gasterophilus nasalis | eggs deposited on hairs of intermandibular area, first instar hatches spontaneously and crawls into mouth, develops to 2nd instar and is swallowed, develop to 3rd instar and live for up to 12 mo in duodenum, pass out in feces in late spring and pupate in soil, adults emerge 3-9 wks later, PPP up to 14 months. |
| Gasterophilus hemorrhoidalis | eggs deposited on hairs around lipss, first instar hatches spontaneously and crawls into mouth, develop to 2nd instar and is swallowed, develop to 3rd instar and live in stomach, before reattaching in rectum, pass in feces in late spring and pupate in soil, adults emerge 3-9 wks later. |
| Musca autumnalis | eggs develop to larvae, three larval instars develop to pupae then adult, females lay batches of 100 creamy-white, 1mm long banana shaped eggs in feces or rotting organic material |
| Stomoxys calcitrans | female lays batches of up to 25-50 creamy-white, 1mm long banana shaped eggs in decaying vegetable matter, lawn clippings, damp hay, feed blood 1-2 times per day, penetrate skin, 3 minutes required for each bloodmeal, allows transmission of organisms. |
| Culicoides spp. | eggs laid in damp marshy ground, hatch in 2-9 days, 4 larval stages completed 2wk-7mo, pupae found at edges of water, adults emerge 3-10 days, females suck blood. |
| Tabanus spp. | after bloodmeal female lays several hundred eggs in muddy/marshy areas, on vegetation/stones, eggs hatch 1-2 wks later as sluggish larvae, develop in 3mo-3years. adult emerges from pupae in 1-3weeks, PPP4-5 mo or longer. |
| Chrysops spp. | after bloodmeal female lays several hundred eggs in muddy/marshy areas, on vegetation/stones, eggs hatch 1-2 wks later as sluggish larvae, develop in 3mo-3years. adult emerges from pupae in 1-3weeks, PPP4-5 mo or longer. |
| Chorioptes bovis | female lays 90 eggs during her lifetime of 4-6 weeks, egg, larval, nymphal stages mature to adult in 10 days, mite feeds only on skin surface and does not pierce. |
| Eimeria leukarti | three phases: sporulation, infection/schizogony, gametogony/oocyst formation. Sporulation: unsporulated oocyst passes in feces, develop to sporoblast, then sporocyst and divides in to 2 banana shaped sporozoites, takes 2-4 days under optimal conditions. oocyst now contains 4 sporocysts each with 2 sporozoites and is infective stage. Infection/Schizogony: host ingests sporulated oocyst, sporocysts are liberated and sporozoites leave sporocyst. each sporozoite penetrates epithelial cell, becomes trophozoite, divides to form schizont containing merozoites. host cell and schizont ruptures and merozoites escape to invade neighboring cells, schizogony repeats, unknown how many times. Gametogony/Oocyst formation: schizogony terminates, merozoites give rise to male and female gametocytes. gametogony occurs, oocyst forms, liberation of unsporulated oocyst by passing in feces, PPP 15 days. |
| Sarcocystis neurona | lifecycle involves gametogony in definitive host and schizogony in intermediate host. Final host: ingests bradyzoite cysts in muscle of intermediate host, bradyzoites liberated in intestine and zoites pass to sub-epithelial lamina propria and differentiate to gametocytes. gametogony occurs and oocysts form and sporulate WITHIN the body, 2 sporocysts each with 4 sporozoites, usually free sporocysts found in feces. Intermediate host: ingests sporocysts and 3 asexual generations occur. in the first, sporozoites are released from sporocysts, invade intestinal wall, enter capillaries, locate endothelial cells and undergo 2 schizogonous cycles. 3rd asexual cycle occurs in circulating lymphocytes, resulting merozoites penetrating muscle cells, encysting and dividing by budding to give rise to broad banana shaped bradyzoites within a cyst. this is the mature sarcocyst and is infective stage for final host. |
| Ostertagia ostertagi | Direct, typical trichostrongyloid lifecycle, eggs pass in feces and under optimal conditions develop in fecal pat to L3 in 2 wks, migrate on to herbage and ingested during grazing, after ingestion L3 exsheaths in the rumen, develops further in abomasal gland. 2 molts occur and adults emerge from gland 18 days later, unless arrested development, then several months later. males and females mate, PPP 21days. |
| Haemonchus placei | Direct, typical trichostrongyloid lifecycle, eggs pass in feces and develop in fecal pat to L3, migrate to herbage and are ingested. larvae develop to L4 in abomasum, and in unfavorable conditions undergo hypobiosis, encyst in abomasal wall and overwinter. in spring larvae emerge, resume development to adult stage, males and females mate, PPP 23-28 days unless hypobiosis, then longer. |
| Cooperia spp | Direct, typical trichostrongyloid lifecycle, PPP 15-18 days. |
| Oesophagostomum spp. | Direct, typical trichostrongyloid lifecycle, eggs hatch in feces and develop to L3, they are ingested and then enter wall of small and large intestine where they develop to L4. L4 can remain arrested for up to 1 year. develop to adults, mate, and lay eggs, PPP about 45 days. |
| Dictyocaulus viviparous | females pass eggs, which hatch to L1, are coughed up and pass in the feces. develop to L3 and migrate up herbage, sometimes with help of fungus Pilobolus spp. reports in some areas that 95% bovine fecal matter are positive for Pilobolus spores. cattle swallow L3 which penetrate intestinal mucosa and migrate to lungs via lymphatic and bloodvessels. mature as adults in trachea and bronchi. PPP 24 days |
| Taenia saginata | gravid segments pass from definitive host, rupture, oncospheres ingested by cattle. oncosphere hatches, penetrates intestinal wall and migrates via blood to the skeletal and cardiac muscle to form cysticerci. cysticerci are not infective during the first 12 weeks of development. they remain viable for 9mo - 2yr after full development. human ingests cysticercus when ingesting uncooked meat. the cysticercus evaginates and becomes adult, attaching in small intestine. PPP 2-3mo. |
| Fasciola hepatica | Indirect, immature stages pass in feces, eggs become embryonated in water, release miracida. miracidia invades snail of Lymnaea species, where it develops from sporocyst, rediae, cercaria. cercaria released from snail and encyst on aquatic vegetation (especially watercress) as metacercariae. final host ingests metacercariae, it excysts to duodenum, through intestinal wall to peritoneal cavity, liver and parenchyma into bile ducts. they develop into adults in bile ducts, PPP 2-3 mo. |
| Fascioloides magna | Indirect, immature stages pass in feces, eggs become embryonated in water and release miracidia. miracidia invade aquatic snail, where it develops from sporocyst, rediae, cercaria. cercaria released from snail and encysts on aquatic vegetation as metacercariae, which final host ingests. it excysts and migrates destructively in liver tissue causing pathogenesis. in deer: fibrous cyst forms around pair of flukes, where they develop to adults and reproduce. in cow: cyst is formed in liver and completely encapsulates fluke, so infection is never patent. in sheep and goats: no cyst formation so juvenile fluke migrates aimlessly and animal dies before infection is patent. PPP 8 mo. |
| Musca domestica | females lay batches of 100 creamy-white 1mm long banana shaped eggs in manure or rotting organic material. 3 larval stages then pupa, then adult. |
| Musca autumnalis | females lay batches of 100 creamy-white 1mm long banana shaped eggs in fresh dung, within 15 minutes of passing. 3 larval stages then pupa, then adult. |
| Stomoxys calcitrans | females lay batches of 100 creamy-white 1mm long banana shaped eggs in decaying organic material such as piles of hay contaminated with urine. feed on blood 1-2 times per day. 3 larval stages then pupa, then adult. |
| Haematobia irritans | eggs 1-1.5mm long laid in freshly passed dung. hatch in 1 day, larva mature in 4 days. adults emerge 6 days after pupa is formed, under favorable conditions. adults remain on cattle host. |
| Cochliomyia hominivorax | adults deposit eggs on fresh open wound, eggs hatch to larva and feed invasively on tissue, fall to ground, pupate, adults emerge several weeks later. females mate once. |
| Hypoderma bovis | adult flies glue eggs to hairs on legs of cattle at END of summer. 1st instar, less than 1mm long hatch in a few days, burrow through skin, migrate and accumulate in epidural fat of spinal cord. then migrate to subQ tissues of back, where they develop to L3 and spend 2 mo as warbles on cow back. larvae emerge through breathing holes and pupate on ground. they emerge as adults about 1mo later, they mate in die within 1-2wks. |
| Hypoderma lineatum | adult flies glue eggs to hairs on legs at BEGINNING of summer. 1st instar, less than 1mm long hatch in a few days, penetrate skin and accumulate in esophagus. then migrate to subQ tissues of back, where they develop to L3 and spend 2 mo as warbles on cow back. larvae emerge through breathing holes and pupate on ground. they emerge as adults about 1mo later, they mate and die within 1-2wks. |
| Damilinia bovis | females lay nits, which develop to nymphs, molt 3 times, then become adult. requires host. whole cycle takes 2-4 weeks. in cold regions, heaviest infestation during winter and early spring when coat is thickest. numbers remain low in summer because pelage is thin, skin temp is high, and parasite doesn't like sun! |
| Linognathus vituli | female lays 200-300 nits, which develop to adults in 1mo. egg hatches to nymph, molts 3 times before becoming adult. requires host to complete lifecycle. PPP 2-4 wks. |
| Haematopinus eurysternus | female lays 200-300 nits, which develop to adults in 1mo. egg hatches to nymph, molts 3 times before becoming adult. requires host to complete lifecycle. PPP 2-4 wks. |
| Amblyomma spp. | all species have three host lifecycle. nymphs drop off of host to molt. females drop off of host to lay eggs and then she dies. |
| Rhipicephalus (Boophilus) spp. | one host tick. female lays eggs, develops to larvae which feed and molt to nymphs, then adults. female drops off of host, lays eggs and dies. Whole cycle takes about 20 days. |
| Otobius spp. | lay eggs in crevices of walls and are mainly a problem in housed stock. only larvae and nymphs are parasitic and stay on host several months, adults non-parasitic. |
| Sarcoptes scabiei | fertilized female burrows and creates tunnels in layers of epidermis. eggs hatch in tunnels within 3-5 days to larvae, which re-surface. larvae burrow and form molting pockets where nymphs and adults develop. all stages surface and reburrow again, PPP 17-21 days. |
| Chorioptes bovis | feeds only on skin surface, female lays 90 eggs in her lifetime of 4-6 wks. PPP 10 days, includes development of eggs to larvae, nymphs and adults. |
| Giardia intestinalis | trophozoites adhere to intestinal microvilli, multiply asexual, then forms cyst. cyst passed in feces, can survive 2-4 weeks. if diarrhea is present, trophozoites may be found in feces, but don't survive. |
| Tritrichomonas foetus | bulls less than 4 tend to clear themselves from infection, older than 4 and bull carries it for life. inhabits prepuce and transfers to cow during coitus. trichomonads reach uterus and cause low grade endometritis. following is early abortion, cow may self-cure, but immunity is not long lasting. |
| Eimeria bovis/zuernii | three phases: sporulation, infection/schizogony, gametogony/oocyst formation. Sporulation: unsporulated oocyst passes in feces, develop to sporoblast, which then develops to sporocyst, divides into 2 banana shape sporozoites, oocyst now contains 4 sporocysts each with 2 sporozoites, is the infective stage Infection/Schizogony: host ingests sporulated oocyst, each sporocyst invades an endothelial cell, now a trophozoite, then becomes a schizont containing lots of merozoites. the merozoites break out and invade neighboring cells. undergo 2 CYCLES. Gametogony/Oocyst formation: schizogony terminates when merozoites turn to gametocytes. mating, zygote forms oocyst, UNSPORULATED oocyst passes in feces. |
| Cryptosporidium spp. | Direct transmission, sporulated oocysts are infective stage. autoinfection occurs. on ingestion of sporulated oocyst, sporozoites are released and invade intestinal and respiratory epithelial cells. 3 stages of asexual/sexual are small and located at microvillar surface of epithelial cells. typically found in young animals. |
| Neospora spp. | easily confused with Toxoplasma because of structural similarities and asexual stages. there is an extraintestinal phase with tachyzoites in groups and bradyzoites in cysts, also an intestinal phase. the tachyzoites are found in neural, marcrophage, fibroblast, vascular epithelium of kidney and liver. they can cross placenta and replicate in fetus. cyst ONLY found in neural tissue. gametogony in intestine produces unsporulated oocyst in feces. sporulation occurs outside host and sporont gives 2 sporocysts each with 4 sporozoites. sporulated oocyst is the infective stage. |
| Sarcocystis spp. | final host: ingests mature sarcocyst with bradyzoites in muscle of intermediate host. bradyzoites liberated in intestine, freed zoites pass in sub-epithelial lamina propria and become gametocytes. form oocysts, SPORULATE WITHIN THE BODY. 2 sporocysts each containing 4 sporozoites. usually ruptures and free sporocysts found in feces. intermediate host: ingest sporocyst, 3 asexual generations, sporozoites released from sporocyst and enter endothelial cells where they undergo 2 schizogonous cycles. the third cycle occurs in circulating lymphocytes. resulting merozoites pierce muscle cells and encyst, form bradyzoites. they undergo hypobiosis. |
| Babesia bigemina | tick vector innoculates sporozoites, they multiply by schizogony in erythrocytes. the host cell ruptures and newly formed organisms infect other cells. ticks become infected by taking infected bloodmeal. generations of schizogony in tick gut form elongated, motile, club-shaped bodies called vermicules. small pyriform bodies will form in salivary cells of tick and form sporozoites which are injected into new host. stages take 7 days. |
| Teladorsagia circumcincta | Direct, typical trichostrongyloid, eggs pass in feces and develop to L3 in 2 wk. L3 migrate onto herbage and are ingested. they exsheath in rumen and develop in lumen of abomasal gland to L4. young adults emerge from the gland in 18 days, mate, lay eggs. L4 may become arrested in intestinal wall for up to 6 months. PPP 21days. |
| Haemonchus contortus | Direct, typical trichostrongyloid, eggs pass in feces and develop to L3. migrate onto herbage and are ingested. exsheath and develop to L4 in abomasum. will undergo hypobiosis and overwinter in gut wall. males and females mate, lay eggs, PPP 18-21 days. |
| Nematodirus spp. | preparasitic phase unique for this Trichostrongyloid because development to L3 takes place INSIDE the shell. development slow, takes at least 2 mo. PPP about 3 wks. free living stage can survive up to 2 years on pasture, emergence of large numbers of L3 at once contribute to pathogenesis. this is a lamb to lamb disease. |
| Strongyloides papillosus | lifecycle has homogonic and heterogonic phase. in homogonic cycle, egg contains fully developed L1 or free L1 is passed in feces. develop to L3 in soil and penetrate host skin, migrate to heart, through lungs and up trachea. swallowed and migrate to intestine. develop to females only and parthenogenesis takes place. some larvae arrest in somatic tissue. PPP 10-14days. When environmental conditions are favorable, heterogonic phase predominates. the free-living larvae hatch and develop to males and females, mate in soil, lay eggs. these infect percutaneously and per os. |
| Dictyocaulus filaria | females pass eggs, hatch to L1, are coughed up and passed in feces. the L3 migrate up herbage, sheep swallow L3, they penetrate intestinal mucosa and migrate to lungs. they break through capillaries in lungs to mature as adults in trachea and bronchi. PPP 5wks. |
| Muellerius spp. | indirect. ovo-viviparous, L1 passed in feces. penetrate foot of molluscan intermediate host and develop to L3 in 2-3 wks. sheep infected by ingesting mollusc and L3 travels to lungs by lymphatic-vascular route. parasite molts in mesenteric lymph nodes and lungs and develops to adult. PPP 6-10wks. |
| Moniezia spp. | mature proglottids pass in feces, disintegrate, release eggs. develop to oncosphere, ingested by orbatid mite. embryo migrates into body cavity of mite and develops into cysticercoid in 1-4 mo. infection of final host by ingestion of infected mite during grazing. PPP is 6 wks. |
| Taenia hydatigena | oncosphere ingested by intermediate host, carried in blood to liver where they migrate for 4 weeks. emerge to surface of liver and attach to peritoneum. cause hepatitis cysticercosa. within 4 weeks develop to cysticercus in peritoneal cavity. final host ingests cysticercus, develops to adult tapeworm in small intestine. |
| Melophagus ovinus | adults live several months, female produces 1 egg which hatches and develops through 3 instars inside female. third instar adheres to wool. pupate immediately are 3-4mm and brown. adults emerge in 3 weeks in summer, each ked produces 1 larvae every 2 weeks so can produce a total of 15. heavy infestations seen in autumn and winter, can't survive very long off the host, entire lifecycle occurs directly on host. |
| Sarcophagidae | 3000 species, each has their own preferred site of tissue infestation. the L1 to L3 in decomposing tissue. then drops off, pupates in soil. pupa overwinters. adults are non-parasitic. |
| Oestrus ovis | L1 deposited by viviparous female, who spurts liquid with 25 larvae into host nasal cavity. female instars remain in nostrils 2wk in summer and 9mo in winter. develop to 2nd instars, attach to mucous membranes with oral hooks causing severe irritation. enter frontal sinus and develop to L3, fully grown 3cm long. stay in sinuses for 21 days, then sneezed out and pupate in soil for 4-7 weeks. females survive 2 weeks, depositing up to 500 larvae in host nostrils. |
| Linognathus pedalis/ovillus | female lays 200-300 eggs develop to adults in a month. eggs hatch to nymphs, molt 3 times and then adult. requires host to complete cycle, PPP 2-4wks. |
| Damalinia ovis | female lays 200-300 eggs develop to adults in a month. eggs hatch to nymphs, molt 3 times and then adult. requires host to complete cycle, PPP 2-4wks. |
| Psoroptes ovis | female lays eggs during her lifetime of 4-6wks. has piercing/chewing mouthparts, pierces skin with stylet-like chelicerae. feeding results in exudation of serum, which hardens to form a scab. PPP 10days. |
| Eimeria spp. | three phases: sporulation, infection/schizogony, gametogony/oocyst formation. Sporulation: unsporulated oocyst passes in feces, develop to sporoblast, then sporocyst and divides in to 2 banana shaped sporozoites, takes 2-4 days under optimal conditions. oocyst now contains 4 sporocysts each with 2 sporozoites and is infective stage. Infection/Schizogony: host ingests sporulated oocyst, sporocysts are liberated and sporozoites leave sporocyst. each sporozoite penetrates epithelial cell, becomes trophozoite, divides to form schizont containing merozoites. host cell and schizont ruptures and merozoites escape to invade neighboring cells, schizogony repeats, unknown how many times. Gametogony/Oocyst formation: schizogony terminates, merozoites give rise to male and female gametocytes. gametogony occurs, oocyst forms, liberation of unsporulated oocyst by passing in feces, PPP 15 days. |
| Hyostrongylus spp. | Eggs develop to L3 in 1-2 weeks. they are very motile and migrate up herbage, pigs ingest L3. they inhabit the gastric glands, develop to L4, and mature on the mucosal surface. eggs appear in feces in 18-21 days. egg excretion per female is low compared to other nematodes. larval stage may undergo hypobiosis for several months. |
| Ascaris suum | direct lifecycle, eggs pass with feces, immediately embryonate in soil, may reach the infective stage within 1-3 mo. pig ingests, egg with L2 hatches in small intestine. hepatic tracheal migration follows. final molts take place in intestine and eggs passed in feces in 6-8 weeks. if an earthworm ingests the egg, the L2 will hatch and travel to tissues and become paratenic host. lavae remains infective in environment for long period. female nematode produces 200,000 eggs/day. |
| Strongyloides ransomi | direct lifecycle, has homogonic and heterogonic phases. in homogonic cycle, egg contains fully developed L1 or free L1 is passed in feces. develop to L3 in soil and penetrate host skin, migrate to heart, through lungs and up trachea. swallowed and migrate to intestine. develop to females only and parthenogenesis takes place. some larvae arrest in somatic tissue. PPP 10-14days. When environmental conditions are favorable, heterogonic phase predominates. the free-living larvae hatch and develop to males and females, mate in soil, lay eggs. these infect percutaneously and per os (grass and milk). |
| Oesophagostomum spp. | direct, typical strongyloid lifecycle. adult females produce large numbers of eggs in large intestine, they hatch a few days after deposition in the feces, develop to L3. larvae have low motility and tend to stay in feces, pig ingests larvae from environment and L3 enter mucosa of large intestine where form nodules and molt. emerge to surface of colon and develop to adult within 3-8wks. |
| Trichuris suis | adults in cecum and colon produce eggs that are excreted with feces. larvae develop to L1 in egg and are ingested by pig. larvae released and development takes place in epithelium of intestine. anterior end of adults embed in mucosal surface of cecum and colon. egg prod occurs after 6 weeks. |
| Trichinella spp. | L1 encyst in striated muscle with high larval densities in masseter and diaphram. muscle eaten by final host and larvae liberated, undergo 4 molts in small intestine. become sexually mature, adults produce embryonic prelarval stages, enter lymphatic vessels of gut, travel via bloodstream to muscle and become encapsulated after 3-4 weeks. develop to L1 in muscle and encyst. adults and larval stages occur in same host. |
| Metastrongylus spp. | direct and indirect. adults located in small bronchi/bronchioles. produce eggs containing L1 that pass up the trachea, are swallowed and pass through feces. eggs are ingested by earthworms as intermediate host, and development in earthworm can take years. pig becomes infected by eating earthworm, L3 released and migrate to mesenteric lymph nodes, where they molt, migrate through lymphatics to lungs. L3 may be infective with or without earthworm. |
| Taenia solium | humans become infected by ingesting adult tapeworm in raw pork. eggs of tapeworm pass from human and ingested by pig, develop to cysticercosis, with hundreds/thousands of small cysts forming in muscle, heart, brain. |
| Haematopinus suis | female lays 200-300 eggs, develop to adults in 1 month. egg hatches to nymph, after 3 molts become adult. requires host to complete lifecycle. whole cycle 2-4 weeks. transmitted by direct contact between pigs. |
| Balantidium spp. | cysts passed in feces are ingested, the trophozoites are released in the digestive tract, where they undergo asexual multiplication. humans become infected by contamination of food/hands with pig feces. |
| Ascaridia spp. | direct, infective L2 in the egg ingested and hatches in small intestine. parasitic stage is non-migratory. larvae embed into mucosal layers of small intestine. phase has duration of 3-54d before final maturation in lumen. there is a normal histotrophic phase of this cycle. paratenic host sometimes involved. PPP 5-8wk. worms live up to 1 year. |
| Heterakis spp. | direct, earthworms and houseflies can act as mechanical vectors. non-embryonated eggs pass in feces and develop to L2 within egg. host ingests this stage and eggs hatch in small intestine. within 24 hours larvae reach cecum where they develop to adults. may have tissue phase before becoming adults. PPP 24-30days. |
| Capillaria spp. | Direct or Indirect. Direct: eggs embryonate in feces and develop to L1. eggs are ingested and hatch/develop to adults without migration. C. obsignata, C. anatis, and C. contorta are always direct lifecycle. Indirect: eggs swallowed by earthworms and develop to infective stage. bird ingests earthworm. C. caudinflata, C. bursata, and C. annulata are always indirect lifecycle. PPP is 2mo for both direct and indirect. |
| Syngamus trachea | Direct with paratenic host. develops to L3 in egg. egg may or may not hatch, bird acquires by ingesting L3 in egg, hatched, or in paratenic host. encysted larvae are long-lived, migrate to lungs. young nematodes mate and take up residence in trachea, where develop to adult. eggs coughed up, swallowed, passed in feces. PPP is 3 weeks. |
| Choanotaenia spp. | after eggs pass in feces, ingested by intermediate host and hatch. IH beetles and houseflies. eggs develop to cysticercoid and are ingested. after 2 weeks gravid segments are released in feces. |
| Raillietina spp. | gravid proglottids are passed with feces and eggs may survive a considerable time. IH are ants and beetles. develop to cysticercoid in IH and is ingested by bird. activated by bile in the final host, the cysticercoid attaches to the mucosa in small intestine. development of proglottids starts immediately. PPP 2-3wks. |
| Echidnophaga spp. | female is fertilized and she burrows into skin of fowl usually on comb and wattles, forming nodules. lays eggs in the nodules, larvae drop to ground to complete development. skin over the nodules often ulcerates. |
| Cimex spp. | bugs hide in crevices by day and feed on sleeping host by night. lay eggs in hiding places, eggs hatch and nymphs molt 5 times, taking bloodmeal between each molt. can starve for months. |
| Argas spp. | ticks deposit eggs in clutches of 25-100 in crevices which serve as hiding places in the day. several clutches laid each preceded by bloodmeal lasting 45 minutes. larvae hatch, attach to host and feed 5 days. develops to nymph and molts 3 times off host, taking bloodmeal between each molt. lifecycle is 30 days. |
| Dermanyssus spp. | adult females lay eggs after bloodmeal. lay eggs off host. larvae hatch and nymph molts 2 times, then adult, entire cycle less than 7 days. can live up to 8 months with bloodmeal. |
| Ornithonyssus spp. | adult female lay eggs on or off host after taking bloodmeal. larvae hatch, nymphs molt 2 times, then to adult in 24-48 hours. entire cycle less than 7 days. Can survive only 10 days off host. |
| Knemidocoptes spp. | mites pass entire lifecycle on host, chickens infested through contact with soil or animals. |
| Histomonas spp. | free trophozoites in feces have no role in transmission and die. trophozoites in the eggs of H. gallinarium are passed in feces and infective to other birds. in intestine, trophozoites released from nematode egg and invade cecal wall. protozoon loses its flagellum and becomes pleomorphic and amoeboid. migrates to liver. |
| Spironucleus (Hexamita) spp. | cause infectious catarrhal enteritis in young birds, primary infection is droppings from carrier birds. outbreaks result from build-up of organisms through several broods of poults, making exposure of brood overwhelming. indirect transmission may result from fecal material carried on shoes or equipment. free-flying birds may also be carriers. |
| Trichomonas spp. | trophozoites reside in oral-nasal cavity and upper GIT, where they multiply by binary fission. 3 modes of infection. 1. infective trophozoites passed by adult pigeons and doves to squabs in "pigeon milk". 2. for turkeys and chickens to ingest recently contaminated drinking water as the trophozoites live only a short time outside of their host. 3. for birds of prey to be infected by ingesting an infected prey bird. |
| Eimeria spp. for birds | sporulation, infection, asexual reproduction (schizogony or merogony) and sexual reproduction (gametogony) and oocyst formation. |
| Leucocytozoon spp. | birds infected when bitten by blackfly or biting midge. sporozoites enter bloodstream and enter hepatocytes where first generation schizonts develop. subsequent schizonts develop in brain, heart, lungs, liver, kidney, gizzard, intestine, and lymphoid tissue. develop possibly in lymphoid or macrocytic cells. megaloschizonts develop to merozoites, at some stage schizonts rupture, merozoites released in blood. cycle continues indefinately or merozoites enter lymphocytes, monocytes, or erythrocytes and for micro- or macrogametocytes. fertilize and form oocysts in the vector. oocyst matures to sporozoites in stomach of blackfly/midge, they break out, pass to salivary glands and are introduced into avian. PPP 2wks. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.