Parasitic Diseases- Arthropods Flashcards
what are the 2 classes of arthropods?
- arachnida
2. insecta
what are the 2 types of arachnida? how many legs?
mites and ticks; 8 legs
what are the 4 types of insecta? how many legs?
- lice
- flies
- mosquitoes
- fleas
6 legs
give 3 common characteristics for arthropoda parasites
- most of them only spend a portion of their life cycle in the host
- depend on the host as a nutritional booster for a specific life event
- all of them are extracellular and most are macroparasites and ectoparasites
what are the 7 yucky things that arthropod parasites do?
- blood-sucking
- surface-feeding on secretions
- surface-feeding on skin debris
- flesh-eating
- burrowing
- develop under skin
- mites in hair follicles
describe ticks (their yucky do and significance)
blood-sucking ectoparasites of worldwide veterinary significance
where are ticks especially important?
warmer, wetter regions
are ticks species-specific?
not as a general organism, but there are specific ticks for many species
what are the 3 stages of tick life cycles?
- larva
- nymph
- adult (male or female, they differentiate and sexually reproduce)
how many hosts can ticks have?
1 (direct) 2, or 3 (indirect)
describe a one-host tick life cycle
female leaves host to lay eggs in grass, the eggs hatch and larvae come back to the host to get a boost to mature into nymphs, then a boost to mature into adults, males and females reproduce, and cycle starts over
what is an example of a one-host tick?
Boophilus, or cattle fever tick, acrry Babesia, which is a pathogen that can cause fatal disease in cattle
do ticks have eyes? what does this mean in their life cycles?
no eyes, so they just wait at the top of grass until a host runs by/brushes against them and they go for the ride of life :’)
describe a 2-host tick life cycle
adults suck blood to reproduce, the female leaves the final host to lay eggs in grass that hatch into larvae and are picked up by the second (intermediate) host, larvae mature into nymphs, which drop of 2ndary host and molt into adults that wait in grass for final host
describe a 3-host tick life cycle
each pahse of development is in a different host
females leave final (3rd) host and lay eggs that hatch in the environment, the larvae attack the 1st host to get their boost, then drop off and mature into nymphs that attack the 2nd host for their boost and drop off to mature into adults that attack, mate, and feed on the 3rd/final host
why are there fewer parasites seen in controlled environments than non-controlled environments? (like less in dairies vs beef)
can control the entire life cycle of parasite, stop at all points/stop cycle
what are the direct effects of ticks? (4)
- mechanical injury
- anemia
- paralysis
- toxicosis
what causes diseases in tick hosts?
a neurotoxin present in tick saliva
what is the main host response to ticks?
prurito, or the urge to scratch the body, thus removing ticks
how do tick evade the host response of prurito?
there is a chemical in tick saliva that can quiet the prurito response and allow invasion of host
for what disease do ticks act as vectors? (5)
bunches, but specifically
- coxiellosis/Q fever
- rocky mountain spotted fever
- Lyme disease
- colorado tick fever
- tularemia
describe treatment and prevention of ticks (3)
- use of pesticides (acaricides)
- removal of ticks
- field magagement
what 2 other dieases does Q fever/coxiellosis look like and why?
Brucellosis or mono because causes joint pain
what must you ensure in removal of ticks and why?
get the head! if left behind it could cause infection
what is the emerging problem with using pesticides against ticks?
resistance
what is the name of common mange in pigs and dogs?
Sarcoptes scabiei
what other animals commonly get their own kind of mange? don’t need to know name
cats
in what animals is sarcoptic mange rare?
horses and sheep
what are the clinical signs of sarcoptic mange?
- papules
- scaling
- crusting
- excoriations
- severe pruritus
describe transmission of sarcoptic mange
through direct contact with infected animals or contaminated fomites
what decreases an animal’s risk for mites?
a good immune system
what increases an animal’s risk for mites? give an example
a poor/weak immune system; stray/feral animals are stressed and have lower immunity, leading to lots of mites and other parasites
describe treatment of mites
is difficult! but use acaricides
what is the blood-sucking mite that infects chickens, turkeys, pigeons, and various wild birds worldwide?
Poultry red mite, aka red mite, roost mite, or poultry mite
why are poultry red mites rare in commercial cage-layer operations?
due to the all-in, all-out, clean in between nature of the operations
where are poultry red mites usually found?
in cage-free environments such as breeder or small farm flocks
when do poultry red mites feed? what do in day?
nocturnal feeders that hide during the day
describe the life stages of poultry red mites
larva to nymph to another nymph to adult
how long after infested birds are removed can poultry red mites remain in environment?
up to 9 months
where do most poultry red mite infections occur?
around the eyes
what do heavy infestations of poultry red mites cause (6)?
- decreased reproductive potential in males
- decreased egg production in females (mites sucking all the blood)
- decreased weight gain in young birds- bad for broiler farms
- decreased feed conversion efficiency
- anemia
- death
describe the host range of lice and why you don’t need to worry about dog lice
largely host specific
what kind of ectoparasites are lice?
obligate ectoparasites, gotta do it
what are the 2 types of lice?
- blood-sucking
2. chewing/biting
in what animals are blood-sucking lice found?
only in mammals, not in birds
in what animals are chewing/biting lice found? describe head and why it’s like that
found in mammals and birds; bigger head to eat secretions and oils
where do lice live?
within the microenvironment provided by the skin and its hair or feathers
how are lice transmitted?
primarily by contact between hosts
what disease can lice cause and why?
pediculosis: manifested by pruritus and dermal irritation, with resultant scratching, rubbing, and biting of infested areas
how do you treat lice (2)
- cut hair (easier in dogs than cattle)
2. ectoparasiticides
how many species of fleas are there worldwide?
over 2200
what yucky thing do fleas do?
blood-sucking
what is the most prevalent flea species in North America?
Ctenocephalides felis (cat flea); infests over 50 different mammalian and avian hosts throughout the world
what do symptoms do fleas cause?
severe skin irritation in animals and people due to blood sucking
what diseases are fleas vectors for?
- Rickettsiae
2. Bartonella spp.
what parasites are fleas intermediate hosts for? how does that cycle work?
filaria and cestode parasties, proglottids in feces, dogs lick and ingest fleas, now those larvae inside dog too
what is the only life phase of the flea that lives in/on host?
adult
where do fleas lay eggs?
outside host, in environment
describe the life stages of fleas
eggs to larvae to pupae to adults
describe control of fleas (3)
- elimination ON pets via insecticides
- elimination of existing ENVIRONMENTAL infestation
- prevention of subsequent infections
can you only eliminate fleas on pets and be fine and flea free?
no, you must also eliminate the existing environmental infestation
what is the problem with the use of insecticides to eliminate fleas on pets?
resistance
what are the 2/3 methods of eliminating an existing environmental infection of fleas?
- residual insecticides to kill newly acquired fleas
- insect growth retardants
- combination of both
describe prevention of subsequent reinfection of fleas
elimination of fleas in the yard/garden and dog houses
what is flea allergy dermatitis?
an immunologic disease caused by infection of antigens from salivary glands of fleas as they feed on hosts
what does flea allergy dermatitis cause in dogs?
pruritis and papulocrustous lesions destributed on the lower back, tailhead, and caudal and inner thighs
what does flea allergy dermatitis cause in cats?
pruritis and papular dermatitis found on the face, neck, and back
what is control of flea allergy dermatitis based on?
treatment and prevention of flea infestations, along with supportive care for dermatitis
what does the order diptera of insecta include?
not only the common house fly and many other insects we commonly call flies, but also mosquitoes
what feature are diptera characterized by?
2 wings
what do diptera feed on? (4)
- blood
- saliva
- tears
- mucus
what bad thing do diptera do?
spread bacteria, viruses, and parasites
what are the 2 types of diptera? describe
- biting flies: feed on animal blood
2. nonbiting flies: feed on bodily secretions
what are the 4 life stages of diptera?
- egg
- larvae: flies at this stage look like worms, are maggots
- pupa: cocoon
- adult
where are fly eggs laid? (3)
- decaying flesh
- animal waste
- pools of standing water
what is myiasis?
infestations of larvae in animals
what types of diptera cause myiasis?
bot flies
what are cat bot flies called?
Cuterebra flies
how are cat bot flies transmitted?
females deposit eggs on stones or vegetation, and cats become infested as they pass through contaminated areas and the larvae enter the cats’ skin
what symptoms do cat bot flies cause?
swellings with breathing pores around the head, neck and trunk, with the hair around the skin matted and swollen
where can cat bot fly larvae also develop other than the head, neck, and trunk? (4)
brain, nose, throat, and eyelids
what are botflies in horses called?
Gasterophylus flies
describe the pathogenicity of bot flies in horses
considered benign, even though some pathology is observed
how can bot larvae in horses be identified?
during oral inspection or gastroscopy
how do you treat bot flies in horses?
ivermectin
what are bot flies in sheep called?
Oestrus ovis
describe the direct life cycle of Oestrus ovis (sheep bot fly)
the female deposits larvae in and about the nostrils of the sheep, the larvae then enter the nasal cavity and migrate to the paranasal sinuses, where the larval period lasts 1-10 months before mature larvae leave nasal passage (sneeze) and drop to the ground
what symptom is caused by sheep bot flies?
nasal discharge
how do you treat sheep bot flies?
ivermectin
describe the life cycle of bot flies in horses
larvae hatch from eggs in horse stomach, exctreted in feces and are pupal stage in pastures, and the adult fly emerges from feces where they live on horse hair until the horse licks/ingests them and the cycle restarts
