parasite exam 1

Zoonoses

• transmissible infections from animals to people

parasite

• organisms that live on or insde a larger organism and gets food from it

symbiosis

• relationship between two different kinds of living things that live together and depend on each other

mutualism

• association between organisms of two different species in which each benefits

definitive host

• host in which the parasite completes its reproduction cycle

intermediate host

• additional host required in the life cycle, immautre helminth stages

paratenic host

• optional additional host

direct life cycle

• one host required

indirect life cycle

• more than one host required

dead end host

• one from which further transmission cannot occur

pre-patent period

• the period between a host becoming infected and the reproductive stages beign detected usually in feces.

patent infection

• infection during the period when the parasite is reproducing within the host, and you can diagnose the infection.

Are parasites always harmful

• no

• for example demodex mites are everywhere but if there is an outgrowth then they will a problem

• rumen also contains intestinal microbiota used for fermentation.

taxonomy of Genus

• Cryptospoidium

• must be caps

• underlined or italized

taxonomy of species

• parvum

• not caps

• underlined or italized

taxonomy complete

• Cryptosporidium parvum

classifying parasitic infections

• over dispersed

• negative binomial

• long tail

• 80/20 rule

• treat sick animals with higher parasite load or negative binomial

transmission

• high stocking density (host crowding)

• younger animals

• pregnant and lactating animals

• selection pressure causing microbial resistant infections

• immuno-deficits causing immunomodulation and immunosuppression in hosts

• opportunistic parasitic infections

current problems

• limited drug options

• effectiveness questionable

• resistace is increasing

• few drugs in development and process is slow

• vaccines are difficult

• solution - understand epidemiology of helminths so we can use less drugs, dose them appropriately and only use when necessary

phylum apicomplexa

• named for the apical complex where there is a collection of organelles which helps to orchestrate entry to cells

• apicoplast - has a separate genome which is evidence of an algal plant endosymbiont origin

apicomplexa intracellular or extracellular

• apicomplexa is an intracellular parasite

apicomplexa motile

• they move by gliding, there is not flagella

apicomplexa plasmodium

• most notorious for human and avian malaria

apicomplexa eimeria

• poultry and farm animals

apicomplexa cyrptosporidium

• many host species

apicomplexa toxoplasma gondi

• definitive host - cats, wide variety of paratenic hosts)

apicomplexa neospora

• definitive host - carnivores, intermediate hosts for some hervivores.

apicomplexa babesia

• variety of definitve hosts, ticks are intermediate hosts

Eimeria environmental stage

• oocyst 20-30um (much smaller than nematodes)

Eimeria unsporulated or sporlated when emerges from host

• unsporulated

Eimeria sporulate in envronmet

• 4 sporocysts, each with 2 sporozites

Eimeria infective stage

• sporulated oocyst (banana shapped)

Eimeria environmental resistence

• survives a range of environmental conditions, resistance to harsh conditions

Eimeria schizonts

• cyst formed by sporozites which rupture out of cells releasing merozites

Eimeria peak damage

• at last stage of schizongony

Eimeria damage

• oocyst/sporocyst walls removed mechanically and chemically in host GIT

sporozoites invade what after being released from sporocysts

• invades gut cells

Eimeria host

• host specific

reproduction asexual

• schizongony, each nd creates further pathology

reproduction sexual

• sporogony

Eimeria control

• management, diagnosis, remediation, medication prevent rapid build up of sporocysts, low humidity, good husbandry, vaccines

Eimeria treatment

• antheliminthics

Eimeria diagnosis

• fecal float

Eimeria clinical signs

• huddling, ruffled feathers, bloody poop

Eimeria in poultry

• hugely sifnificant issue in commericial poultry production

Eimeria in poultry clinical signs

• mortality, reduced feed conversion, ruffled feathers, huddling, blood in feces

Eimeria in poultry control

• ALL IN ALL OUT SYSTEM

• keep litter dry

• humidity low

Eimeria in poultry prevention

• vaccine but controversial so main thing is all in all out system

precocious strain vaccine bird Eimeria

• shorter PPP, avoids last generation of schizongony which is the most pathogenic

Apicomplexa Cystisospora (Isospora) host

• Dogs and cats

Apicomplexa Cystisospora morphology

• 2 sporocysts with 4 sporozites in each

Cystisospora envrionmental risk

• humidity, heat, overcrowding

Cystisopora pathology

• in large numbers, diarreha, failure to thrive

cystisopora disease

• coccidiosis

Cystisopora treatment

• only with high numbers and clinical signs

Eimeria vs Cystisopora

• eimeria has BLOODY diarrhea

• cystisopora NO blood in diarrhea

Apicomplexa Cryptosporidium

• smallest prozoa in lab and is more of a round shape vs banana shape

• over 30 species from 200 hosts

Cryptosporidium morphology

• small ooxysts (5-8um)

• 4 sporozoites, NO sporocysts

• sporozoite is surrounded by vacuole with material from the host and parasite

Cryptosporidium life cycle

• sporulation inside the host

Cryptosporidium location

• intracellular, extra-cytoplasmic

Cryptosporidium pathology

• destruction of epithleial cells and absorptive villi, self limiting with few clinical signs

• exception: neonates, immunosuppressed individuals

Cryptosporidium diagnosis

• ELISA , fluorescent stain, hard to see on floats, acid fast stain, PCR

Cryptosporidium zoonosis

• direct and waterborne

Cryptosporidium resistances

• oocysts extremely resistant even to chlorine water disinfection.

Cryptosporidium hosts

• young calves

• lambs and kids

• foal heat diarrhae

Crypto pathology

• weakness, potential mortality, dehyration

Crypto clinical signs

• watery diarrhea, rapid onset diarrhea

Crypto PPP

• 3-7 days

Crypto control

• hygiene in calving pens, prevent build up of oocysts in environment.

Crypto prevention

• decrease infection pressure good husbandry