Exam 2 Flashcards
Which parasite is responsible for Nasal Acariasis?
pneumonyssoides caninum/nasal mites
What drugs can you use to treat nasal acariasis? Which ones are FDA approved?
Imidacloprid/moxidectin, milbemycin oxime, selamectin, ivermectin,
none are approved
Which parasite is responsible for nasal capillariasis?
Eucoleus boehmi
What is the diagnostic stage of E. boehmi? Describe its morphology.
Embryonated egg
Yellow-brown, bipolar plugs, asymmetrical poles, smooth walled, embryo does not fill egg completely, barrel shaped egg,
Higher plane of view may reveal pitted surface on one end of egg underneath the plug
What drugs can be used to treat E. boehmi? Which ones are FDA approved?
fenbendazole, ivermectin, imidacloprid/moxidectin, milbemycin oxime
None are FDA approved
What do you have to worry about when treating dogs for E. boehmi with ivermectin?
Ivermectin toxicity in predisposed breeds
Which parasite is known as the “Lungworm”
Eucoleus aerophilus
Describe the life cycle of Eucoleus aerophilus
Eggs are shed in feces, develop in environment to become larvated (infective), larvated eggs are ingested and larvae hatch and migrate to lungs, mature in fine bronchioles and alveoli, adults deposit eggs inside lungs and the eggs are coughed up and swallowed to be shed in feces
Which drugs can be used to treat Eucoleus aerophilus? which of these are FDA approved?
Dogs: Fenbendazole and ivermectin
Cats: moxidectin
NPA
What drug is effective against T. vulpis, E. boehmi, and E. aerophilus?
Moxidectin
Name where each of these parasites live in the D.H.
T. vulpis, E. boehmi, E. aerophilus
T. vulpis: colon and cecum
E. boehmi: nasal turbinates and sinuses
E. aerophilus: bronchi and trachea
How can you distinguish T. vulpis, E. boehmi, and E. aerophilus eggs from each other
T. vulpis: symmetrical bipolar plugs, smooth shell, embryo fills entire egg
E. boehmi: asymmetrical bipolar plugs, embryo does not fill entire egg, smooth shell
E. aerophilus: symmetrical/asymmetrical bipolar plugs, rough/striated shell, embryo fills entire egg,
You find a Capillaria egg in your cat’s feces, how can you determine if your cat is being parasitized by a feline capillaria or a rodent/bird capillaria
Confine cat for 3 days and recheck fecal for eggs. No eggs = cat was just passing capillaria eggs from ingesting an infected animal. Yes eggs = cat is being parasitized by feline capillaria
True/False: cats and dogs can be infected with Filaroides osleri
False, Filaroides osleri only infects dogs, coyotes, and wolves
What other parasite have we covered also forms nodules similar to Filaroides osleri?
Spirocerca lupi, forms esophageal nodules
What is unique about the larval stage of Filaroides osleri
Diagnostic and infective stage are the same (L1 larvae)
Where does development of all 5 stages (L1-Adult) of Filaroides osleri occur?
Lungs
What are the different ways a dog can get infected with Filaroides osleri?
Ingestion of L1 larvae (in feces), vomitus/saliva/stomach contents containing L1, bitch –> pups during cleaning
How can you diagnose a Filaroides osleri infection?
Sedimentation exam (look for L1 larvae) or endoscopy (look for nodules at tracheal bifurcation)
How can you differentiate Filaroides osleri larvae from S. Stercoralis larvae?
F. osleri larvae have “S” shaped tail with a slight kink
S. stercoralis have a straight tail and are recognized by prominent genital primordium
What drugs can be used to treat F. osleri infection, which ones are FDA approved?
Fenbendazole and ivermectin
NPA
How can you tell if F. osleri infection has been cleared?
- Disappearance of clinical signs
- resolution of nodules
- disappearance of larvae from feces
What is the domestic host for Aleurostrongylus abstrusus?
Cat
Describe the life cycle for A. abstrusus
Female worm deposits eggs in bronchioles and alveoli, L1 larvae hatch and move up airways via mucociliary action and are coughed up and swallowed to be shed in feces. Larvae molt to L3 in snail/slug I.H. which is ingested by a cat and migrate back to lungs
Is the severity of clinical signs correlated to degree of infection for A. abstrusus?
Yes
What diagnostic technique can you use to recover the diagnostic stage of A. abstrusus? Describe the morphology of the diagnostic stage
Baermann technique
L1 larvae, curled body with S-shaped tail that has a small spine, 350-390 um long
What drugs can you use A. abstrusus infections and which ones are FDA approved?
Emodepside/praziquantel, Imidacloprid/moxidectin, selamectin
none are approved for treating this specific worm, but these are all approved drugs for treating other parasites in cats
Which parasites are responsible for “Paragonimiasis”
lung flukes
Why is Paragonimus kellicotti only found east of the Rocky Mountains?
Its snail I.H. is only found east of the Rockies
What is the life cycle of P. kellicotti?
What is relatively unique about its lifecycle?
Eggs are coughed up and swallowed –> eggs are passed in feces –> miracidium hatches and penetrates snail (I.H. #1) –> cercariae leave snail to penetrate crayfish (I.H. #2) –> encyst as metacercariae –> ingested by D.H. –> excyst in the intestines –> penetrate abdominal cavity –> migrate to lungs and encyst to mature flukes (live inside cysts)
2 I.H.’s, paratenic host (rat) may ingest crayfish and have metacercariae encyst in tissues
What are your diagnostic options for Paragonimus kellicotti?
Sedimentation for egg recovery or radiographs for cyst and nodule detection in liver
What drugs are available to treat P. kellicotti?
Which ones are approved by FDA?
Fenbendazole, Ivermectin
NPA
Is Paragonimus kellicotti zoonotic?
Yes, radiographs look similar to tuberculosis, flukes can mature and reproduce in humans, treat humans with praziquantel
What natural definitive host serves as a reservoir for Dirofilaria immitis?
coyotes
What is the length of microfilaria? Diameter?
270-340 um long, 6-8 um wide
Detail the life cycle of Dirofilaria immitis
Females in pulmonary arteries deposit microfilariae into curculation, mosquito feeds on infected dog and ingests microfilariae in the process, microfilariae undergo change from L1 to L3 (infective stage) within 8-30+ days, L3’s migrate to salivary glands of mosquito, mosquito feeds on uninfected dog and deposits L3 larvae AROUND the bite wound, L3 migrate into opening made by bite wound and reside in SC tissue where they molt to L4 within 3-12 days post infection, L4 migrate through to SC tissues or muscles in thorax and molt to immature adults within 45-70 days post infection, immature adults enter circulation and are swept into pulmonary circulation within 70-120 days post infection, immature adults mature and mate and females produce microfilariae 6-7 months post infection
T/F: microfilariae = L1 larvae
T/F: L1 larvae are infective stage
T/F: Mosquitos do not actually deposit L3 larvae directly into the D.H.
False
False (L3 are infective stage)
True
Can you have a persistent heartworm infection in a cat population if there are no dogs/coyotes nearby?
No
Which stages of the D. immitis life cycle can be found in circulating vasculature?
Microfilaria, Adults
Which life stages of D. immitis can only be found within the mosquito?
L1, L2, L3
Where are the L4 larvae of D. immitis found?
in the SC tissues and thoracic (intercostal) muscles of the D.H.
What happens to placentally transmitted microfilariae?
When should you start adminsitering heartworm preventatives?
They will not mature past microfilariae stage (require mosquito I.H. in order to continue development)
As early as the label allows
What differences will there be in terms of L3 larvae inside the body of a dog who has lived outdoors in area with a high prevalence of heartworm disease vs. a dog that has lived indoors its entire life?
Outdoor dog will have built up immune system towards D. immitis and will kill most L3 larvae.
Indoor dog will not be able to fight off L3 infection much and will have a more severe infection in the long run
In most dogs, clinical signs of heartworm infection will not manifest until _______
the worms mature
T/F: Number of worms is more important than activity level of the infected dog in terms of severity and progression of disease
False, activity level may be more important
What are the pathological possibilities of adult heartworm burdens? (hint: 5 main outcomes)
1) Progressive pulmonary hypertension –> right ventricular hypertrophy
2) Obstruction of blood vessels and heart chambers and valves
3) inflammatory mediators induce immune complex glomerulonephritis
4) Caval Syndrome (sudden exposure to large number of worms –> accumulation of immature adults in posterior vena cava)
5) Wolbachia pipientis - gram (-) parasite of D. immitis that produces endotoxins
What is required for D. immitis to progress to L4 larva stage
Wolbachia pipientis symbiote
What pathology can you expect from microfilariae?
1) obstruction of fine capillaries
2) immunological response to death of microfilariae may form immune complexes within glomeruli and impair kidney function –> proteinuria
How does Caval Syndrome occur?
If a dog is fed on by large number of mosquitoes (within few days of each other) harboring many L3 larvae that that all mature in close proximity, leading to obstruction of right atrium, tricuspid valve, and posterior vena cava
What do D. immitis antigen tests look for?
Female worms (female uterine antigen)
What is the earliest age you should run a heartworm antigen test? (according to American Heartworm Society)
7 months
What are the ways in which you can get a false negative antigen test?
1) low worm burden may not be detected
2) Immature females (recent infections)
3) male only infections will show up as false negative
4) Not allowing test kit to warm to room temp
5) dogs/cats who have already been exposed previously may have antibodies in circulation that bind to antigen, making it unavailable to bind to antigen test
What does a negative test result tell you on an antigen test? If you want to make a reasonable assurance that the animal is truly free of adult heartworm infection, what can you do after getting a negative test result on an antigen test?
all a negative test says is that no antigen was detected which is not the same as no worms detected, or that there are even no antigens
You can conduct another test (separate, different test)
How can you get a false positive antigen test result?
1) well-type tests in which the wells were not properly washed
2) cross reaction with other antigens (from Spirocerca lupi infection)
3) other unknown antigens or test error
4) residual circulating antigen following elimination of adult worms (recent treatments)
When would be an optimal time to run an antigen test (for D. immitis) on a patient?
late afternoon due to nocturnal periodicity of microfilariae
What is the correlation between number of microfilariae and number of adult worms
Low
What parasite has microfilariae that can be confused with D. immitis microfilariae?
How can you differentiate the 2 microfilariae?
Acanthocheilonema sp.
Acanthocheilonema sp. :have blunt body anteriorly, may have button hook tail, generally thinner and shorter in body size than D. immitis. Produce few microfilariae, these are capable of moving across a glass slide
D. immitis: have tapered body anteriorly, straight tails, body size overall is larger than Acanthocheilonema sp., D. immitis microfilariae are 270-340 um long, do not move across glass slide
What does it mean if your patient has an occult infection of D. immitis?
Adults are present but there are no microfilariae
This can be due to having a prepatent infection (sexually immature worms), unisex infections, drug-induced reduction of microfilariae, immune-mediated clearance of microfilariae (animals who have had previous exposure and developed some immunity)
What are some scenarios in which you would want to conduct a microfilaria test in tandem with an antigen test?
Dogs with low number of female worms can be antigen negative but microfilaria positive
Dogs with immune complexes binding female antigen could be antigen neg. and microfilaria positive
Early developing infections in some dogs can be antigen negative and microfilaria positive
What kind of drugs are current heartworm preventatives?
macrocyclic lactones which are avermectins and milbemycins
avermectins to note: ivermectin, selamectin
milbemycins: milbemycin oxime and moxidectin
What are the dosages, routes of administration, and frequency for treating heartworms with ivermectin, milbemycin oxime, moxidectin, and selamectin?
Ivermectin @ 6.0 ug/kg, oral. monthly
Milbemycin oxime @ 0.5 mg/kg, oral, monthly
Moxidectin @ 0.17 mg/kg, injectable, 6 months
Moxidectin @ 2.5mg/kg, topical, monthly
Selamectin @ 6.0 mg/kg, topical, monthly
Which stage of the D. immitis life cycle is targeted by monthly preventatives?
L3 and L4 larvae in SC tissues
microfilariae - but this is not part of the preventive action
What are the 3 desired outcomes of treating a dog, with a macocyclic lactone, infected with heartworms?
prevent further infections, prevent maturation of (kill) L3 and L4 larvae that may be present, eliminate infected dog as a potential reservoir
administration of _______ @__mg/kg BID for _____ prior to treatment is to eliminate _____ from _______ before adulticide treatment
This will ______ the pathology associated with worm death
Doxycycline, 10, a month, Wolbachia, D. immitis, lessens
What is an important part of treatment in a heartworm positive dog that does not involve the use of drugs?
Exercise restriction (cage rest, sedation, walking on a leash) in order to reduce chance for pulmoanry embolism
What drug is an FDA approved adulticide for D. immitis?
What is the dosing regimen for this drug?
Melarsomine - deep I.M. injection
Split dosing into a 3 dose regimen
1st dose at 2.5 mg/kg then 1 month later give a 2nd dose 2.5 mg/kg then 24 hours later give 3rd dose at 2.5 mg/kg
When would a surgical approach be most appropriate for treating D. immitis infection? What other treatment is involved in this approach?
Use surgical approach in caval syndrome, Sx is followed by 2-3 dose course of melarsomine because it is likely that not all of the worms were removed during the surgery
When switching from 1 heartworm preventive to another, when should you test the patient for heartworms?
when the switch occurs, 6m after switch, 12m after switch, then annually
this way you can completely evaluate efficacy of new preventive
Cats are ______ but ______ hosts to D. immitis
resistant, susceptible
?/3 of D. immitis infections are single gender infections in cats.
1/3
How many adult worm(s) are needed to kill a cat?
just 1 is enough
For D. immitis in cats,
PPP=?
life span of adults =?
microfilaria are common/uncommon and numbers are high/low
Low/high mortality of immature adults as they first reach lungs
PPP = 7-8months
Life span = 2-3 yrs
Microfilaria are uncommon and numbers are low
high mortality
What is needed in the environment to have heartworms in cats?
nearby reservoir of infected dogs/coyotes for mosquitoes to feed on
What is HARD?
What happens in stage 1 of this in cats?
How may a cat present to you clinically if it has stage 1 HARD?
Heartworm Associated Respiratory Disease
75-100 days after infection: Immature adults arrive at caudal pulmonary arteries. Intense inflammatory response from lungs, type II cell hyperplasia and activation of pulmonary intravascular macrophage which results in occlusive medial hypertrophy of small pulmonary arterioles & bronchi, bronchioles, alveoli, and pulmonary arteries
asthma-like symptoms
True/False: a cat can have mild to severe life-threatening respiratory disease and have no mature heart worms
True
When does Stage 2 Hard occur?
Do the heartworms that survive the initial immunological reaction in the cat cause much pathology?
What happens when these adults die?
Can this intense immune reaction be stimulated from just a single worm dying?
1-3 years post infection
No
Intense immunological reaction in cat, lungs become extremely inflamed and PIM become key players in intense reaction, resulting in non-functioning lung and acute respiratory distress syndrome
Yes
What is responsible for the life-threatening event in HARD?
actue edema of lung leading to respiratory failure or heart failure?
lung failure
Where might you find adult heart worms in a cat on necropsy?
polumonary arteries, lobar arteries of the lungs, right ventricle & atrium, posterior vena cava
Is aberrant migration more common in cats or dogs?
Cats
Are single sex or multi sex worm infections more common in cats?
Why might this be?
single sex
Cats are not natural definitive host
How many adult worms are needed to cause sudden death in a cat (due to acute pulmonary infarction and lung injury)
1
What 2 serologic methods are available for HW testing?
Adult female uterine antigen test
Antibody directed against molting larvae
Why is antigen testing not very reliable in cats?
More common in cats to have male only infections, tend to have low worm burdens thus low female count, symptomatic immature infections, immune complexes bind antigen
What is the general rule of thumb on interpreting antigen tests for HW disease in cats?
Can trust a positive result, can not trust a negative result
Antibody testing:
what does this test detect?
How soon can you get a positive AB titer
How long does it take for L3 to molt to L4
What does a positive test result mean?
Does a positive Ab test indicate presence of adults?
detects antibodies produced in cat in response to early migration (molting) of L3/L4 larvae
1-3 months post infection
3-12 days
Exposure to infective larvae
No
Can AB positive, but heartworm negative cats (no adults at necropsy) have hypertrophy of pulmonary arterial walls?
Yes
Are radiographic signs to help diagnose heartworm disease more prominent in dogs or cats?
What about ultrasound?
Dogs
Cats
Most feline heartworm cases are/are not amicrofilaremic, thus ______ test will typically be postive/negative
are, Knott’s, negative
What ultrasonography finding is indicative of HW disease
presence of double-lined echodensity in main pulmonary artery
Why is treating/not treating adult heartworms in cats a lose-lose scenario?
treat: killing worms with adulticide all at once can cause acute complications
do not treat: waiting for cat to clear infection on own over several years and continue to suffer or risk of acute crisis in future
HW Dz:
Melarsomine Tx in cats is/is not recommended. Melarsomine in cats/dogs is more toxic
Typical treatment in cats is _______
is not
cats
supportive Tx (parenteral fluids, prednisolone, oxygen therapy, cage rest)
What prophylactic drugs are available for HW’s in cats?
Ivermectin, milbemycin oxime, moxidectin, selamectin
For these prophylactic drugs (for HW’s) for cats:
What are the dosages and route of administration for each drug?
Selamectin
Moxidectin
Ivermectin
Milbemycin oxime
Selamectin: 6mg/kg topically
Moxidectin: 1.0 mg/kg topical (2.5x lower than dose in dogs)
Ivermectin: 24 ug/kg oral (4x dose of dogs)
Milbemycin oxime: 2mg/kg oral (4x dose of dogs)
What is the vector for Babesia canis?
Rhipicephalus sanguineous (Brown Dog Tick)
What life stage of Babesia spp. is found within erythrocytes?
trophozoite stage ( feeding stage-piroplasms)
Generally, what distinction can be made from Babesia canis piroplasms and Babesia gibsoni piroplasms?
B. canis: larger (2.5 um), occur as paired trophozoites (piroplasms)
B. gibsoni: smaller (1.9x1.2 um) tend to appear as single piroplasms,
Describe the life cycle for Babesia canis vogeli, starting from piroplasms in the blood
Piroplasms and/or merozoites are taken up by tick when it feeds on infected dog –> piroplasms undergo gametogony –> sporozoites –> migrate to salivary glands/ovaries of the tick –> infect dog with sporozoites when tick feeds
Is the tick or the dog considered the intermediate host in Babesia canis vogeli? Why?
The dog
B/c Babesia undergo gametogony in the tick, infective stage is in the tick,
What happens when a Babesia merozoite stage is released from a destroyed RBC?
it invades other RBC’s or are taken up by a tick
T/F: with Babesia infections, you do not have to be worried about transplacental transmission to the puppies from the mother
False, transplacental transmission can occur
What modes of transmission can Babesia undergo inside the tick?
Transstadial: transmitted from life stage to life stage
Transovarian: babesia organisms transmitted from infected female tick through her eggs to the progeny
Which life stages are part of transstadial transmission in the tick?
larva-nymph-adult
What is the suspected mode of transmission of Babesia gibsoni?
inoculation from infected blood during dog fights
Transplacental transmission has been documented as well
When are Babesia canis vogeli cases seen in dogs
adults/puppies that are stressed
What happens to RBC’s infected with Babesia?
They change in size, shape, pliability, antigenicity
Host’s immune system does not recognize and they are destroyed
Many times, a dog infected with Babesia is ______ until it undergoes a _______ event
asymptomatic, stressful
What are the ways to diagnose Babesia infections, what are you looking for for each test?
Which one is the best test?
blood smear: look for piroplasms
serology: antibody titers greater than or equal to 1:64 ratio which indicate prior or current infection
Best test - PCR: DNA
What is the problem with current treatments for Babesia?
What are they?
Give drug name, doseage, route of administration, frequency of treatments
No Tx available that are 100% safe and efficacious
Imidocarb diproprionate 6.6mg/kg SC/IM once and repeat in 2 weeks
Combo therapy azithromycin 10mg/kg PO q24h and atovaquone 13.5 mg/kg PO q8h for 10 days
Is Babesia spp. considered to be zoonotic?
No!
What is considered the definitive host of Cytauxzoon felis?
Lone Star Tick - Amblyomma americanum
What might you find on a blood smear of an animal with Cytauxzoonosis
round, oval, or ring shpaed piroplasms inside erythrocytes
What is considered to be the natural reservoir host for Cytauxzoon felis?
Bobcats (Lynx rufus)
Describe the life cycle of Cytauxzoon felis, starting from an infected tick biting a cat
Sporozoites are injected into the cat in tick saliva –> sporozoites invade endothelial-associated mononuclear phagocytes –> schizogony occurs inside the phagocytes –> formation of schizonts –> infected macrophages adhere to vessel walls and physically obstruct blood flow, particularly in liver, lungs, spleen –> merozoites are released when schizonts within infected macrophages rupture and invade erythrocytes –> once inside RBC’s, piroplasms feed, grow, and RBC’s are destroyed
What causes the pathology seen in cats with cytauxzoonosis?
large histiocytic macrophags containing schizonts attach to vascular endothelium of lungs, kidney, lymph nodes, and spleen, causing blockage of vessels and impeding blood flow –>widespread organ failure
The cats are NOT dying from ruptured red blood cells
Timeline of disease onset in cats with cytauxzoonosis?
5-15 days after tick bite, cats develop signs of illness (anorexia, weight loss, depression, pale mucous membranes, high fever)
3-6 days after onset of clinical signs, body temp drops below normal, icterus followed by respiratory signs, death usually in 5 days
How can you diagnose cytauxzoonosis in cats?
blood smear - look for piroplasms in erythrocytes, schizonts in macrophages,
PCR
what treatment options are available for cytauxzoonosis?
Are any of them approved by the FDA?
atovaquone (15mg/kg PO) and azithromycin (10mg/kg PO) combination therapy
supportive treatment
No
What is the definitive and intermediate hosts for Hepatozoon americanum
D.H. = Amblyomma maculatum (Gulf Coast Tick)
I.H. doge
How can dogs become infected with hepatozoonosis
Dogs ingest the tick containing sporulated oocysts, oocysts rupture, releasing sporozoites that penetrate intestine walls, migrate to striated muscle and undergo schizogony in phagocytic cells between myocytes
Histologically, what might you see in the muscle tissue of a dog infected with hepatozoonosis
layers of granulomatous tissue due to schizonts in phagocytic cells between myocytes, “onion skin disease”
what is the infective stage of Hepatozoon americanum
sporulated oocysts inside the tick
What might predispose a dog to being infected with hepatozoonosis?
exposure to tick vectors, ready access to prey animals, living near coyote population (suspected wildlife reservoir)
What is the hallmark diagnostic finding in dogs infected with hepatozoon americanum?
(profound) neutrophilic leukocytosis - 20,000 to 200,000 cells/uL
Why should steroids not be used in hepatozoonosis infections?
inhibition of immune system could lead to huge increases in #’s of parasites
What is another name for Chaga’s Disease? What species are we predominantly concerned with this disease?
Canine American Trypanosomiasis
Dogs, racoons, and humans
What is the name of the parasite that causes Trypanosomiasis?
Trypanosoma cruzi
a protozoa with a single flagellum
What do you call the life stage of Trypanosoma cruzi that is found in the blood?
What do you call the life stage that is found within host tissue?
Trypomastigote
Amastigote
What is responsible for transmission of Trypanosoma cruzi?
“kissing bugs”
Bugs of the genera Triatoma, Reduviidae
How can Trypanosomiasis be transmitted?
Feces of infected bugs is rubbed into bite wounds, ingestion of bug feces, ingestion of infected bugs
What kind of tissue does Trypanosoma cruzi have preference for?
In cases where humans infected with Trypanosomiasis die, what do they die from?
Cardiac and smooth muscle
stationary amastigotes inside cardiac muscle undergo binary fission, destroy host cells and cause tissue damage
What is the standard method of diagnosis for Trypanosomiasis?
Serology (IFA testing)
What is required prior to obtaining benzinidazole for use in treatment of Trypanosomiasis in dogs?
approval from the CDC
What can you do to help prevent this disease?
prevent dogs from eating bugs, house dogs indoors at night, prevent dogs from eating potentially infected animals, test breeding females (prevent congenital transmission)
T/F: humans can acquire trypanosomiasis directly from infected dogs
T/F: Chaga’s Disease is the most common cause of congestive heart failure in the world
False
True
What drugs are available to treat Dipetalonema (Acanthocheilonema) reconditum?
are they FDA approved for this parasite?
Ivermectin, milbemycin oxime
no
What is the normal host of Dracunculis insignis?
raccoon
What is the life cycle of Dracunculis insignis? (start with adult females in subcutaneous tissues)
when parasite senses contact of infected area of skin with water, female adult exposes anterioir end (exposing part of uterus), deposits L1 into water, L1 taken up by copepod, L1–>L3 in copepod, host infected when it ingests copepod while drinking water, L3 penetrates intestinal walls and migrates to subcutaneous tissues and matures
How do you remove adult dracunculis insignis?
is it zoonotic?
surgical removal of worms
No
What parasite causes Thelaziasis
Thelazia californiensis
Where does Thelaziasis occur, both geographically and in the infected animal?
west coast, nevada, arizona, new mexico
tear ducts, conjunctival sacs, nictitating membrane
What parasite is similar to toxoplasma in cats, a fatal protozoa in dogs and other animals, causes bovine infertility and abortion, used to be misdiagnosed as T. gondii?
Neospora caninum (canine neosporosis)
What is the definitive host of Neospora caninum?
dogs and coyotes
Can Neospora caninum be transmitted transplacentally?
Yes
How do intermediate hosts of Neospora caninum become infected?
Ingestion of sporulated oocysts
What might be some clinical signs of puppies infected with Neospora caninum
progressive hind limb lameness and hyperexension
What is the genus and species of the Giant Kidney Worm
Dioctophyme renale
What are considered to be the definitive host of Dioctophyme renale?
various carnivores, dogs, minks,
How would you know that you are looking at an egg belonging to Dioctophyme renale
if egg is collected from urine sedimentation, has a brownish color, is bipolar, thick shell,
What genera is responsible for Urinary Capillariasis
Pearsonema
How would you know that you are looking at an egg belonging to Pearsonema spp.?
If egg was collected from urine, single celled, bipolar, “capillarid” type egg
If you find a capillarid type egg from a litter box sample (feces contaminated urine), and are not sure if it belongs to a Capillaria from a bird or mouse, what can you do to find out for sure if the cat is being parasitized?
Confine cat for 3 days, recheck urine, if no eggs found then the first eggs seen belonged to a mouse or bird capillaria (cat not parasitized) if eggs are seen, then cat has active infection
What family do hard ticks belong to? Soft ticks?
hard = ixodidae soft = argasidae
List the genera and species for each of the following:
Lone Star Tick Gulf Coast Tick American Dog Tick Rocky Mountain Wood Tick Pacific Coast Tick Western Black-Legged Tick Black Legged Tick Spinose Ear Tick Brown Dog Tick
Amblyomma americanum Amblyomma maculatum Dermacentor variabilis Dermacentor andersoni Dermacentor occidentalis Ixodes pacificus Ixodes scapularis Otobius megnini Rhipicephalus sanguineus
The 8 hard ticks we are concerned with are deemed 3 host ticks. What does this mean?
The tick has 3 life stages (larva-nymph-adult), each with a different host
What are some important generalities of Ixodidae?
each life stage feeds for 2 weeks at most, each life stage must feed to molt to next stage, time for egg-adult takes anywhere from 3 months to 3 years, mating generally occurs on host (exception: ixodes spp. can occur on or off host), females feed much more than males (engorge),
What happens after an adult female engorges?
it drops off host, lays eggs, and dies
What is the main morphological differences between larva (seed tick), nymphs, and adults?
Do larvae and nymphs have sexual differentiation?
larvae have 6 legs, nymphs and adults have 8 legs (and are bigger)
No
How do ticks sense host odors, CO2, visual cues?
Haller’s Organs
Generally, where are Dermacentor variabilis found?
Where are Dermacentor andersoni found?
West coast, midwest, eastern U.S.
Northwest
What is the preferred habitat of D. variabilis and andersoni?
what host does the larva, nymph, and adult prefer?
grassy meadows, young forests, along roadways
larva: small rodents
nymph: medium sized mammals (rarely dogs/cats)
adults: mammals
What are possible pathogens and their corresponding diseases carried by D. variabilis and andersoni
Rickettsia rickettsii (Rocky Mountain Spotted Fever) Francisella tularensis (Tularemia), Tick Paralysis, Cytauxzoon (Cytauxzoonosis)
Where is Dermacentor occidentalis found?
What does the larval and nymph stage like to feed on?
What do adults like to feed on?
What pathogen and disease can it carry?
California
immature stages: rodents, rabbits, squirrels
adults: cattle, dogs, horses, deer, humans
Rickettsia rickettsii (Rocky Mountain Spotted Fever)
What is Dr. Dryden’s Favorite Tick?
Amblyomma americanum
What is the range of the Lone Star Tick (Amblyomma americanum)?
anywhere east of kansas, including northern and southern states
What habitat is preferred by Amblyomma americanum?
What is linked to the distribution and abundance of this tick?
What is this tick’s preferred host?
woodlands with dense underbrush
White-tailed deer population
White-tailed deer
If you find a tick on a dog/cat/human in Kansas during the spring or summer, and it looks small brown and round, which tick is it?
What life stage is it?
Amblyomma americanum
Nymph stage
What is the major disease associated with Amblyomma americanum?
Cytauxzoonosis
If a pet owner calls you and says they found a Lyme disease tick or a Deer tick, what tick are they probably referring to?
Ixodes scapularis (Black Legged Tick)
What is the distribution of Ixodes scapularis?
What has caused expansion of this tick?
What habitat is preferred?
midwest, eastern, southeastern U.S.
Expansion of white tailed deer
Woodland areas (with adjacent brush/grass, sandy or loam-sand areas)
What host is preferred by Ixodes scapularis larva, nymph, and adults?
How do they become a vector for lyme disease?
Which life stages can transmit lyme disease?
What other diseases is this tick considered a vector for?
larva :rodents, birds, lizards
nymph: birds, cats, rodents, humans, raccoons, opossum
adult: white tailed deer, medium sized mammals,
larva pick up lyme disease from feeding on infected small mammal
nymphs are first stage that can transmit lyme disease, adults can transmit as well
Ehrlichiosis, Anaplasmosis, Babesia (humans)
Regarding life stages, what is the difference between cat and dog infestations of Ixodes?
Cats tend to have nymphs around ear margins and eyelids (rarely adults/larvae)
Dogs tend to have adults (rarely nymphs)
How can you tell the difference between Ixodes scapularis and pacifiucs?
the geographical region in which the tick was found
T/F: Ixodes pacificus are active fall through spring (including winter)
True
What is the distribution of Ixodes pacificus
West Coast
What pathogens and diseases are associated with Ixodes pacificus
primarily Borrelia burgdorferi (Lyme Disease)
What is the preferred host of the larva, nymph and adult of Rhipicephalus sanguineus?
What is unique about this tick’s preferred habitat?
dog,Dog, DOGGG
likes to live inside buildings
What are the possible diseases that Rhipicephalus sanguineus is considered a vector for?
Ehrlichiosis, Babesiosis, possibly Rocky Mountain Spotted Fever
What is the distribution of the Spinose Ear Tick?
Drier parts of U.S., southwest, as well as general southern U.S., but can be found in parts of northwest
The Spinose Ear Tick is/is not currently known for any disease transmission, it feeds for a short/long time on host
If it is known to transmit disease(s), what are they?
is not
short
T/F: Otobius megnini larva and nymphs are not parasitic, but the adults are.
What is unique about the life cycle of this tick compared to the hard ticks?
False, immature stages are parasitic, adults are not
1 host life cycle, larva feed on host –> molt to nymphs –> engorged nymphs drop off host and crawl into a safe place in environment to develop into adults and lay eggs
What tick diseases can be transmitted transovarially? Transstadially?
transovarian: Babesia, RMSF, Cytauxzoon
transstadial: Babesia, RMSF, Cytauxzoon, Lyme, Anaplasma, Ehrlichiosis,
T/F: no tick product in U.S. can claim 100% prevention of tick transmitted disease
True
What are the class of drugs called that are available for tick prevention in dogs?
What major drugs are they?
Why is selamectin not recommended for tick control?
Isoxazolines
Afoxolaner (oral)
Fluralaner (oral)
Sarolaner (oral)
slow speed of kill
What drugs are available for tick control in cats?
What drugs should not be used? Why?
Fipronil (topical)
Flumethrin/imidacloprid (Seresto collar)
Fluralner (topical)
Permethrim amitraz (TOXIC)
What drugs are sued by professional services to treat outdoor areas of a home for tick control?
Cyfluthrin and Bifenthrin
How can you distinguish Sarcoptes scabiei under a microscope?
small, roughly circular body, short legs, covered with triangular spines, long unjointed pedicles
What are the major clinical signs associated with Sarcoptes scabiei?
Severe pruritis, alopecia, papulocrustous eruptions, secondary pyoderma
What are some ways to diagnose Sarcoptes scabiei?
history, clinical signs, positive pinnal-pedal reflex, skin scrapings, owners may be scratching, antibody ELISA, positive response to therapy
What drugs are available to treat Sarcoptic mange that are FDA approved? Unapproved?
What other drugs should you give besides the ones to kill the mites?
approved: Selamectin (topical), Moxidectin (topical)
Not approved: Isoxazolines, Ivermectin (beware breed sensitivity aka collies), milbemycin oxime
antibiotics (for secondary skin infections) and steroids (control pruritis)
Sarcoptes in humans is/is not zoonotic
If it is zoonotic, is it self-limiting?
is zoonotic
self-limiting but not always
How might you identify Notoedres cati under a microscope?
How can you diagnose it?
No spines, thumbprint pattern of folds,
Skin scrapings, clinical signs (intense pruritis, alopecia of face)
What drugs can you use for treatment of Notoedres cati? Which ones are FDA approved?
Selamectin topcial, Moxidectin topical, ivermectin
None are approved
What parasite is responsible for Follicular Mange or Red Mange?
Demodex canis
Are Demodex considered commensal organisms of the skin? Why would they cause disease if they are?
Yes, disease manifests when host has immunological defects
How is Demodex transmitted?
through mother’s milk when puppies are nursing
Not considered to be a truly contagious disease
What are the 3 forms of disease that can occur with Demodex canis?
Localized Demodectic Mange
Juvenile on-set generalized demodectic mange
Adult on-set generalized demodectic mange
How old are dogs typically when they show signs of localized form of demodectic mange?
Is this form self-limiting? Why?
Can this form progress to Juvenile generalized form?
Clinical signs?
less than 1 yr old
yes, b/c this form is not related to compromised immune status or heredity`
yes, about 10% of them do
Usually 1-5 small, well demarcated areas of alopecia, erythema, scaling. confined to around lips, periorbital area, forelimbs, usually no pruritus or pyoderma,
How does Juvenile Onset generalized Demodicosis present usually?
extensive generalized areas of alopecia, erythema or a number of localized lesions
initially may present similar to localized form
How does Adult Onset generalized Demodicosis present?
extensive generalized areas of alopecia, erythema or a number of localized lesions (similar to juvenile form, but in older dogs)
How can you diagnose Demodectic mange?
Deep skin scrapings, scrape again if you can’t find any, pinching and squeezing area of skina s you scrape may help find better results
Can you treat localized and generalized Demodectic mange the same way?
NOOO
How do you treat localized Demodectic mange?
Prognosis?
let lesions resolve on own if not severe, if pruritic then can use spot treatment of benzyl peroxide
Excellent
How would you treat generalized Demodectic mange?
Which Treatment option is considered the current gold standard?
Prognosis?
Downsides to treatment?
First, make sure infected dogs are not used for breeding, conduct additional tests to determine underlying neoplastic or debilitating disease (stress on immune system).
Amitraz dip (mitaban) -FDA approved: every 2 weeks for 4-12 treatments (MUST CONDUCT SKIN SCRAPINGS EACH MONTH AND CONTINUE Tx 4 WEEKS AFTER NEGATIVE SCRAPING)
Ivermectin (0.2-0.6 mg/kg)-NOT FDA approved: give for 60-90 days daily PO (considered GOLD standard)
Isoxazolines (NOT FDA APPROVED)
Also dispense antibiotics to treat for secondary pyoderma
guarded-poor
prolonged, expensive, no guarantee of success
Once a dog has been cleared of Demodex after presenting with adult generalized form, what should be done 6 & 12 months after last treatment?
clinical exam and skin scrapings
Is Demodex zoonotic?
NO
What species causes Demodicosis in cats?
What causes the short form of disease in cats?
Demodex cati
Demodex gatoi
Are both species of demodex in cats considered contagious? Why is it contagious?
no, only gatoi (short form)
resides on epidermal surface instead of hair follicles
How would you diagnose Demodicosis in cats?
What treatment options are available? Which ones are not?
Clinical signs and skin scraping findings
Lime sulfur bath every 7-10 days for 4-6 weeks
amitraz should NOT be used (TOXIC)
How would you identify Cheyletiella sp under a microscope?
large mite, large hook-like palpable claws (unique identifier)
What animals serve as hosts for Cheyletiella sp?
Zoonotic?
Dogs, cats, rabbits
yes
How can you diagnose Cheyletiella sp?
Microscopic examination of sediment collected with clear tape, superficial skin scraping, fecal flotation, sedimentation of coat debris and water and check under microscope
What is the best treatment for Cheyletiella sp? Is it FDA approved?
Selamectin 6-12 mg/kg topical
Not for Cheyletiella, but it is for other parasites
What causes Otoacariasis?
Predominant host?
Location on host?
Otodectes cynotis
Cats
external ear canal, head, neck,
Pathology and clinical signs of Otodectes cynotis?
Diagnosis?
hypersensitivity reactions leading to secondary infections, sometimes will develop otitis (pruritic otitis externa)
Head shaking, scratching, brown exudate from ears
History, otoscope exam, ear swabs+microscopy
How might you identify otodectes cynotis under a microscope?
mite with very long legs
Treatment options for Otodectes cynotis?
Miticidal Otic Preps: Acarex (ivermectin), MilbeMite (milbemycin oxime)
Selamectin (6-12 mg/kg) topical
Moxidectin 1 mg/kg topical
What genera do Chiggers belong to?
What is the most natural definitive host?
Trombicula spp.
lizards
What is the parasitic stage in the life cycle of chiggers?
Can they infect humans? Are Humans considered a natural host?
larval stage
Yes, no
How do chiggers feed?
pierce skin and inject salivary secretion containing digestive enzymes that break down the skin cells and suck up the mixture
Treatment options for Chiggers and treating their symptoms?
Fipronil (dogs/cats, permethrin (dogs - TOXIC TO CATS), treat outdoors with acaracides
anti-inflammatory, anti-histamines, corticosteroids,
What parasite causes pediculosis? (also known as pthiriasis)
Lice
The order Phthiraptera is commonly subdivided into 2 sub orders, what are these 2 suborders?
Anopleura (sucking lice)
Mallophaga (biting lice)
What is the genus and species of the sucking lice of dogs that we are concerned with?
How can you tell this louse from biting lice?
Linognathus setosus
well developed claws used to anchor to host, head is longer than it is wide
What are the 2 biting lice that we have covered? (1 for dog and 1 for cat)
How can you tell these lice from sucking lice?
Trichodectes canis, Felicola subrostratus
rudimentary claws, head as broad or broader than it is long (head looks very large and wide)
Lice undergo complete/incomplete metamorphosis?
Lice are host/non-host specific? What does this mean?
incomplete
host specific, they are found exclusively on one type of host, Ex: cat louse will not be found on dog, dog louse not on cat
What is unique about the life cycle of lice compared to other ectoparasites we have covered in class?
they complete entire life cycle on the host
the adults lay eggs (nits) cemented onto hair. undergo incomplete metamorphosis. egg>1st nymph>2nd nymph>3rd nymph>adult
How are lice transmitted
direct contact
T/F: biting lice can cause anemia
T/F: dog and cat louse infestations are zoonotic
False, they do not suck blood, feed on skin scales, hair, debris, feathers, etc
False, host specific
What is the diagnostic stage of lice?
Whichever life stage that you happen to find on the host animal
What does myiasis mean?
infestation of a host by fly larvae
What is the primary host of cuterebra spp.?
Where do the adult flies like to oviposit?
rodents, rabbits
Near rabbit burrows or rodent dens
Can myiasis happen in humans?
Yes
What is fly strike?
Stable flies biting ears or face of dogs, especially ear tips
What is the only efficacious repellant for fly strike? Can it be used for cats?
Permethrin, NO, IT IS TOXIC
What flea is the most prevalent species found on dogs and cats? What does this mean about its host specificity?
Ctenocephalides felis (cat flea)
Minimal host specificity
What are the different life stages (in order) of Ctenocephalides felis? What is the development of each life stage dependent on?
Which life stage is the least susceptible to dessication?
When is the earliest time this life cycle can develop?
egg>larva>pupa>adult
Temperature
pupa
14 days
How early can fleas feed, mate, and start laying eggs? How many eggs can a single female flea lay in a day?
Where do the majority of eggs laid end up? How did they get there?
24 hours, 40-50/day
In the environment (areas where the host likes to live), eggs initially laid in hair coat but do not adhere so they “roll off”
What do flea larvae require in order to develop properly?
Which component is muy importante (otherwise larvae will not develop)?
protected microhabitat - moderate temps, high relative humidity, ADULT FLEA FECES (most important), shaded areas if outdoors in hot areas
When talking about flea infestations, what are source points?
Areas in homes where development of eggs, larvae, and pupae occur
What “pseudo-life stage” occurs between the pupa and adult?
What happens when it senses nearby host stimuli?
What happens when a pupa finishes developing to the next stage but senses no host stimuli nearby?
Pre-emerged adult
will emerge from cocoon
pre-emerged adult will stay in cocoon until it senses host stimuli, leads to delayed emergence OR will stay in cocoon until it dessicates or runs out of food
In an environment with regular pet/human activity, when do the majority of fleas emerge from time of egg deposition?
How soon do they die if a host can not be found?
How do adult fleas find a host?
3-8 weeks
1-2 weeks
positive & negative phototaxis
What is the primary route of flea transmission in dogs/cats?
What is the secondary route of transmission?
newly emerged fleas from cocoons
from other infested animals if fleas in environment have not reached reproductive status
Clinical signs tend to be seasonal in the Northern U.S./Southern U.S., and non-seasonal in northern U.S./ Southern U.S.
seasonal in northern, non-seasonal in southern
What is FAD?
Can humans get it?
Sometimes periodic/continuous exposure can be worse than periodic/continuous exposure
Flea Allergy Dermatits (Feline Miliary Dermatitis, humans - papular urticaria): an immunological disease in which a hypersensitive state is produced in the host b/c of injection of antigenic material from salivary glands of fleas
Yes
periodic worse than continuous
By the time a pet owner brings their pet in to you, how long has the flea infestation (egg production and development of immature stages) been going on for?
1-2 months (2-3 generations of fleas)
What are the 3 main objectives of flea control?
Relieving discomfort (kill current fleas on pet(s) and provide continuous protection), eliminate infestation of environment (stop flea reproduction, eliminate immature stages), prevention (provide long term control)
When talking about flea adulticides, what is the #1 factor we are concerned about?
Why is the residual part of this factor so important?
SPEED OF KILL
Killing of newly acquired fleas fast enough to prevent reproduction, markedly reduce injection of salivary antigens (prevent FAD), give rapid relief of newly acquired fleas, provide client satisfaction (fewer fleas observed)
Do topical or oral adulticides have faster speed of kill?
oral (kill all fleas on pet within 3-6 hours)
topical will take from 12-48 hrs
How soon do you need to kill fleas (once acquired) on a pet in order to prevent reproduction?
before 24 hours
What 30 day residuals are available for flea prevention?
What 3 month residuals are available?
What short acting residuals are available?
Afoxolaner, Fipronil, Imidacloprid, Indoxicarb, Sarolaner, Selamectin, Spinosad,
Fluralaner
Nitenpyram (capstar)
What does it mean to break the life cycle at host level? (fleas)
use residual adulticides to kill most newly acquired fleas before they can reproduce (before 24 hrs) and use of insect growth regulators or insecticides with ovicidal activity to kill any eggs that are produced
What does reproductive breakpoint mean? (fleas)
Because of this breakpoint, what do modern preventatives have to make up for this effect?
at what point after adulticide is applied that [drug] becomes low enough that speed of kill becomes so slow that females can start laying eggs before dying?
drugs have combination of adulticides and IGR’s to kill any eggs that do get laid
What are the 2 main ways ovicidal (IGR’s) products work?
What 2 drugs have excellent ovicidal activity?
Juvenile hormone analogues (Methoprene & Pyriproxyfen): disrupts early embryonic development of the larva within the egg (eggs are dead before they are even laid)
Chitin synthesis inhibitors (Lufenuron): disrupt cuticle formation of larva within egg
Selamectin and Indoxicarb
Define/Describe the “development window” (fleas)?
Why does this window occur?
time it takes for biomass in premises to be exhausted, takes 3-8 weeks, sometimes longer. Due to prevention of entry of viable eggs and development of immature life stages
“period of time of development of biomass that will proceed before last flea emerges”
Occurs because there are varying stages of flea development in the environment, thus emerging adults appear at different times leading to varying rates of flea reproduction. Only once entry of new fleas into the life cycle stops can the window begin to close
In addition to medicating a patient with a flea infestation, educating the client on flea life cycles, treating for any secondary problems caused by flea infestation, and treating the premises (outdoors) with insecticides, what must you also do to more effectively reduce the biomass?
Mechanical control of the environment: wash bedding, vacuum carpet, use flea traps, etc.
Also must make sure every pet in household is on flea preventative
Prominent characteristics (morphology) of Ctenocephalides felis?
hairs on posterior end, combs on front
Prominent characteristics (morphology) of Pulex simulans? (flea)
no combs, smooth head
Which flea species is commonly misdiagnosed as a larvae or seed ticks?
Prominent characteristics (morphology)?
Echidnophaga gallinacea “sticktight flea” aka “poultry flea”
no combs, very angular head, prominent stylus used to embed itself in host
What are the drugs used as juvenile hormone analogs for fleas?
Methoprene and pyriproxyfen: disrupt early embryonic development of larva within egg, eggs are dead before they are laid
What drug is used as an insect growth regulator for fleas?
Lufenuron: when female flea feeds on blood (containing drug), drug will kill any developing larva in eggs that are laid
which parasite overwinters better?
Haemonchus contortus or Ostertagia ostertagi
Ostertagia ostertagi
