Parasite Test 3

Monogenea

hermaphroditic worms - parasites of fishes generally, on gills and body - some spp. found in urinary system of host (ex. bladders of frogs&turtles) - typically not pathogenic, but can seriously damage crowded fish populations - have been linked phylogenetically to the Cestodes, but the group may be paraphyletic - spp. are quite niche specific (ex. one species lives on tip of gills, other lives near base of gills) - spp. life spans vary from a few days to several years

Morphology-body divided into cephalic region, trunk, peduncle and opishaptor- anterior end termed prohaptor, bears adhesive, feeding and sensory organs two types - posterior end bears opishaptor,

prohaptor

used for feeding and attachment-anterior end

oncomiracidium

resembles a ciliate in size and shape- larval form of monogenean spp.

Dactylogyrus

many spp. placed here, several spp. of importance to hatchery industry (heavy infection may cause erosion of epithelium, access for bacterial)

Gyrodactylus

some pest spp., but unique among monogeneans in viviparous life history \* larvae held in uterus until sub-adulthood, inside juvenile is another \* juvenile (like a Russian doll, a type of sequential polyembryony), can lead to massive infections

Polystoma

parasite of Old World frogs, worms reproductive cycle synchronized with that of it’s host

Cestoidea

the ultimately adapted flatworm (gutless, with distinct holdfast organ) - endoparasites, almost exclusively found in intestine - reports go back to antiquity - worms are segmented, although not in same fashion as earthworms - Serially reproduced structures = proglottids - worms typically monecious (both sexes in each segment), but dioecious species exist - spp. almost exclusively found in vertebrates, with few exceptions - size varies substantially (500μm for some shark tapeworms to over 100 ft in the whale

Eucestoda

the “true” tapeworms, tegument covered with microtriches (several orders)

scolex

scolex (= “head”) anterior, may be equipped with a variety of holdfast structures \* may be reduced or absent \* typically adorned with suckers, apex may have hooks \* great morphological diversity present

microthrix

unique to cestodes, composed of distal electron dense cap, multilaminar baseplate, base, covered by plasma membrane

cirrus

 A bundle or tuft of cilia serving as foot or tentacle in certain ciliate protozoa. (2) An eversible copulatory organ of male flatworms and other invertebrates

Procercoid

the solid first parasitic larva of some tapeworms that develops usually in the body cavity of a copepod.

pleroceroid

the solid elongate infective larva of some tapeworms especially of the order Pseudophyllidea usually occurring in the muscles of fishes.

cysticercoid

having the scolex filling completely the enclosing cyst. Can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal mucosa.

cysticercus

a tapeworm larva that consists of a fluid-filled sac containing an invaginated scolex and is situated in the tissues of an intermediate host

Hydatid

a potentially serious, sometimes fatal, condition caused by cysts containing the larval stages of the Echinococcus granulosus (E. granulosus) tapeworm (Dog Tapeworm).

Pseudophyllidea

a group of tapeworms whose adults are most commonly found in fish. The group is characterized by having a scolex that usually is armed with two bothria, slits on the dorsal and ventral aspect. The genital pores in this group are located medially on each segment.

Diphyllobothrium latum

common parasite in the gut of fish-eating carnivores (ex. bears) - in N. America, humans may become involved with D. ursi - adults quite large (up to 10 meters) - scolex with bothria, eggs released through uterine pore - ciliated coracidium develops in egg (takes a few weeks) - coracidium loses ciliated covering upon being eaten by copepod (ex. Diaptomus), procercoid develops in hemocoel- fish eats copepod, procercoid burrows into body muscles, develops into plerocercoid (easily seen in fish preparations - once eaten by proper host, plerocercoid develops rapidly, can begin egg laying in 1 to 2 weeks - people become infected by eating raw/uncooked fish-disposal of raw sewage into lakes, rivers may discharge massive numbers of eggs into fish environment

coracidium

The ciliated first-stage aquatic embryo of pseudophyllid and other cestodes with aquatic cycles

Copepod

group of small crustaceans found in nearly every freshwater and saltwater habitat. ex.Diaptomus

gefilte fish

a jewish raw fish dish- promotes the spread of Diphyllobothrium latum the broad fish tapeworm

sushimi

raw fish commonly served with rice and promotes the spread of Diphyllobothrium latum the broad fish tapeworm

Sparganosis (Ouch)

humans get involved with developing plerocercoids of worm, via accidental ingestion of procercoids (ex. in drinking water out camping).plerocercoids may also be transferred to humans from insufficiently cooked wild caught animals, or via “applying” wild animals on ulcers or inflammations - most likely cause of sparganosis in N. America is Diphyllobothrium mansonoides. in some cases, sparganum will asexually bud, causing serious tissue/organ pathology (1000’s of worms may result) - treatment is typically via surgery

Spirometra mansonoides

Cyclophyllidea

the tapeworms most commonly associated with humans and their animals most medically important spp. found in family Taeniidae

Taenia saginata

the human beef tapeworm - may reach size of over 20 meters, over 2000 segments present - eggs are spherical, but not a method for identifying spp. - eggs shipped out in gravid uterus, may crawl out of anus - rupture occurs as segment dries, eggs are released - cattle typical intermediate host, hexacanth embryo penetrates gut, enters blood vessel and exits in muscle tissue.-infective cysticercus develops in cattle muscle - humans become infected by eating uncooked beef - infection most likely in cultures with poor sanitation and moderate/high consumption of poorly cooked beef - cattle will eat human dung (copraphagous) - meat is safe by thorough cooking or freezing - vague symptoms (ex. mild dizziness) common, loss of appetite frequent - infection properly identified by observing a gravid proglottid - treatment via praziquantel or niclosamide

uncooked beef

promotes the contraction of Taenia saginata

Copraphagous

cattle will eat human dung

Taenia solium

the pork tapeworm - a dangerous worm, humans may become involve with adult or cysticerci - life history similar to T. saginata, except hogs are intermediate hosts - adult worm may live for up to 25

cysticercosis

infection of human host with cysticercus of worm \* may occur via accidental ingestion of egg, or via reverse peristalsis of gravid proglottid \* any organ may house cysticeri (eyes, brain, heart) \* death of cysticerci elicits a strong inflammatory response, large infection may cause death

coenurus

larval stage of T. multiceps

Echinococcus granulosus

small worm, adults parasitic in canine small intestine, live 5-20 months - onchosphere develops into unilocular hydatid, typical area of development liver/lungs-life cycle of worm depends on the carnivore/herbivore ecology of the region (ex. wolf-moose or wolf- reindeer),

sylvatic echinococcosis

humans may become involved via association with dogs where domestic herbivores are raised (sheep and sheep dogs)-several strains of E. granulosus demonstrated, strains may be adapted to particular intermediate host - local customs may perpetuate hydatid disease-hydatid disease may not become apparent for years after initial infection - growth limited by infection area, pathology includes: \* growth and size of cyst causes crowding/dysfunction of adjacent tissue \* pressure on bone causes necrosis, fragility

\* rupture of cyst causes anaphylactic shock and instant death

- hydatids normally found during X-ray exams - surgical removal of cyst common, drug albendazole used in inoperable cases \* surgery includes cyst aspiration and injection/withdrawal of formalin

hydatidosis

a potentially serious, sometimes fatal, condition caused by cysts containing the larval stages of the Echinococcus granulosus (E. granulosus) tapeworm (Dog Tapeworm)

Dipylidium caninum

common worm of dogs and cats, often occurs in children \* segments have two sets of reproductive organs \* larval fleas become infected via contamination (hyperparasitism) \* adult fleas eaten by host to complete life cycle

Various cestode orders

Onchoproteocephalidea, Phyllobothriidea, Trypanorhyncha, Caryophyllidea. Rhinebothriidea

Pentastomida

known as the tongue worms, adults generally parasitic in respiratory systems of amphibians and “reptiles” - appear to be highly modified parasitic crustaceans (related to spp. of Class Branchiura) \* sperm structure almost identical to branchiurans \* 18S ribosomal RNA studies show similarity to branchiurans \* cuticle similar to arthropods (but quite thin) \* larval forms “mite-like” - worms dioecious, males smaller than females - adult worms feed on tissue and blood fluids of vertebrate host - appear to produce a strong host immune response, but parasite secretions protect animal (especially when it molts) - intermediate host may be vertebrate or invertebrate, depending on group

Porocephalus

nymphal develop in white mice, adult lives in lung tissue of snakes (ex. rattlesnakes)

Linguatula serrata

causes nasopharyngeal pentostomiasis \* infection achieved when humans ingest raw/uncooked herbivore viscera \* strong prickling sensation in throat typical of infection \* death a common result of infection (rapid asphyxiation)

nasopharyngeal pentostomiasis

Arthropoda

most successful phylum on planet, in terms of species \* nearly a million insects known, 50 thousand arachnids, 30 thousand crustaceans \* serve as hosts and vectors for all types of parasitic animals \* Subphylum Crustacea Parasitic copepods (Subclass Copepoda)

Lernaea cyprinacea

can be a threat to economic valued fishes - species parasitize a variety of fresh and salt water hosts, are especially speciose on fishes-parasitic crustaceans can take on a rather bizarre appearance

Phrixocephalus

anterior is “antler-like”

Branchiura

(Sub-class Branchiura) - small number of parasitic species, but of potential destructive value to hosts

Argulus

fish lice-can be damaging to fish cultures

Sacculina

•cirripeds include the barnacles, highly specialized-female is almost fungus like-

Sacculina Life cycle

larva penetrates a joint of crab, molts into kentrogon larval form • grows in the crab, emerging as a sac (externa), • crab cannot molt, growth impaired • male (phenotypically like an arthropod larva), implants into her body and starts fertilizing her eggs • The crab cares for the eggs • will change behavior of male crab, causing it to behave like a female, will engage in activity to facilitate release and dispersal of eggs

Arachnida

ticks and mites- chelicerate arthropods and share a common morphology • Ticks are important vectors of bacterial disease

Ixodes scapularis

feeds on a wide variety of host, vector host for Borrelia burgdorferi, the etiological agent of Lyme disease \* 25-50% of ixodid ticks infected with the spirochete in NE U.S. • tick borne encephalitis transmitted by several species of Ixodes

Borrelia burgdorferi

 a pathogenic spirochete responsible for Lyme disease via a tick vector. This spirochete causes a characteristic annular rash, arthritis, carditis, and in late stages, encephalopathy.

Lyme disease

is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia

Dermacentor

one of the largest ticks, distinct, ornamental and light-colored marble pattern, relatively short mouthparts

Rocky Mountain Spotted Fever

vectors are D. andersoni and D. variabilis

Siphonaptera

\-the fleas-perhaps THE most important group of animal parasites, in terms of effect on human population (transmission of the Plague, aka Black Death) - flea morphology \* body laterally flattened \* incredible leapers (human flea can jump 33 cm), protein resilin has unusual elastic properties \* fleas have piercing mouthparts as adults, larvae have chewing mouthparts-development \* holometabolous, developmental can vary w/temperature, larvae & pupae can withstand cold temperatrures, long periods w/out food

Resilin

a highly elastic substance consisting of protein chains, found in the exoskeletons of various insects.

sticktight fleas

attach permanently to skin of host w/mouthparts \* female tunga fleas burrow into host skin, and become subcutaneous parasites

Tunga penetrans

(jigger flea) native to Central and South America penetrates skin of human host, female grows to size of pea, larvae exit host and develop on ground-essentially a disease of rodents, transfer to humans via interactions of fleas-Black plague\*- last pandemic at end of 19th century, 992 cases in US between 1900 and 1972-most recent cases in US were rural \* bacteria work to block flea gut, new blood cannot enter, but is contaminated by bacteria and "vomited" back into host wound

Nosopsyllus fasciatus

\-rat flea- may be important in plague transmission from rat to rat, not to humans

Pulex irritans

is human flea, can transmit plague from human to humans, has been recorded from a number of animals (80% of fleas on dogs in Georgia were P. irritans), important in consideration of plague > sticktight flea Echidnophaga embeds in the skin of its host

Ctenocephalides canis /C. felis

dog and cat fleas-common to BOTH dogs and cats, will attack humans, host to cestode Dipylidium caninum

Xenopsylla

cosmopolitan on Rattus spp., important vector of plague and mouse typhus, of much public health significance

Mallophaga

chewing lice- feed on skin, feathers, hair, secretions, other parasitic spp. (mites), blood \* the elephant louse Haematomyzus elephantis also has a trunk \* chewing lice transmit filarial worms in birds

Anoplura

lice wingless, dorsoventrally flattened, generally exhibiting large tarsal claws, development is hemimetabolous - much spp. diversity present (pocket gophers tend to have spp. specific lice)

Pediculus humanus

is the head and body louse of man, head and body types may constitute different species \*ex. only body lice are vectors of typhus (found in cooler climates, where humans wear more clothing \* body lice nits (eggs) are attached to clothing \* transmission best in crowded areas, or by common use of clothes/bedding \* head lice common among school children, may cause discomfort

Phthirus pubis

is the crab louse, name from body form \* lives in pubic region of humans, but may dwell in armpits, beard, etc. \* mouth parts may embed in skin, causes intense itching reaction \* transmission via sexual intercourse, new infection often surprising! - lice of pigs and humans will readily “swap” hosts - lice caused 47 million dollars of loss to sheep and cattle industry in 1965 - lice important vectors of human bacterial disease

Hemiptera

the true bugs - spp. are fluid, blood feeders -bedbugs (Cimicidae) are blood feeders of warm animals

Cimex

human bed bugs- Oeciacus vicarius quite abundant in cliff swallow colonies, can affect growth/weight of young birds \* spp. are night feeders \* bedbug infestations difficult to control

Reduviidae - assassin bug

are essentially predators \* bugs feed on fluid of other animals (ex. bedbugs) \*triatomine forms of family are vectors of Trypanosoma cruzi

Diptera

most medically important of all insect vectors-variation in feeding habits, general common groupings include mosquito, horse fly, house fly, stable fly, and louse fly - Suborder Nematocera includes the filter fly (Psychoda, transmission of nematodes in livestock), Phlebonmine flies (Leishmania transmission),

Culicidae - Culex, Aedes, Anopheles

the mosquitos- various spp. important in viral, protistan and nematode transmission,

Simuliidae - Simulium

the black flies-larval development in fast running streams, long fossil history, transmit Onchocerca, some bird malarias

Tabanid flies

Deer flies- that may "bleed" large herbivores, may transmit viral, bacterial, and nematode parasites \* Loa loa tranmitted by Chrysops \* Trypanosoma evansi tranmitted by Tabanus

Muscid flies

maggot and allied forms-importance to veterinary and medical science, w/ a variety of families \* eye gnats (Hippolates) important in transmitting human pinkeye, bovine mastitis \* Glossina spp. important in transmission of African trypanosomes \* Hippobascid flies are bloodsuckers, pigeon fly transmits bird malaria (Haemoproteus)

(house flies) quite familiar, read text section on their ideal nature for transmitting human disease, T. evansi also tranmitted by the muscid stable fly \* blow flies, screw flies (Calliphoridae) destroy large animal carcasses, the Congo floor maggot is only dipteran maggot know to suck human blood

bot flies

(Oestridae) include human skin bot Dermatobia hominis, stomach bots of large animals

Myiasis

condition of being infected with maggots