External Parasites Flashcards
Ctenocephalides spp adults look like?
3-4mm in lenth, flattened laterally with powerful strong legs for leaping & piercing sucking mouth parts
Ctenocephalides spp life cycle
Egg, Larvae, Pupae, Adult
Ctenocephalides spp eggs look like?
0.5mm in size, white in color & oval in shape
Ctenocephalides spp definitive host?
Dog
Ctenocephalides spp can cause?
Irritation, itching, loss of body condition, flea allergy dermatitis, flea anemia,
disease transmission - hemobartonellosis in cats, dipylidium, & plague
Ctenocephalides spp is diagnosed by?
seeing flea dirt/dander/poop in the fur coat
Plague is caused by?
A bacteria maintains in rodent populationsl
Is a flea an insect or arachnid?
Insect
True/False: Plague is One of the oldest diseases afffecting man
True
Plague is caused by?
• Caused by a bacteria maintained in rodent populations
• Causative Agent: Yersinia pestis
Plague syndrome
◦ Human:
‣ Fever
‣ Chills
‣ Myalgia
• Muscle Pain
‣ Sore Throat
‣ Headache
‣ Lymph Node Enlargement
• Bubonic
‣ Septecemia with development of pulmonary disease
◦ Animals:
‣ Rodents:
• Become ill and die
‣ Cats:
• Fever
• Dyspnea
◦ Difficulty breathing
• Nasal Discharge
• Swollen Lymph nodes
• Septicemia
• Incubation Period:
◦ 2-6 days
• Transmission:
◦ Bite of an infected rodent flea
◦ Handling tissues or fluids of infected animals
◦ Inhalation of airborne bacteria from cats or humans w/ pulmonary disease
Plague is diagnosed how?
Diagnosis:
◦ Culture of lymph nodes aspirate, blood, sputum, & CSF
Plague Treatment, Control & Prevention
◦ Antiobiotics - Penicillin since its a gram + organism
• Control/Prevention:
◦ Prevent human contact w/ wild rodents
◦ Uses insecticides/repellents when entering wildlife habitats
◦ Wear gloves when hunting or handling wildlife
◦ Keep dogs/cats from hunting wild rodents
◦ Vaccinate Individuals at risk
Otodectes cynotis
• Common Name:
◦ Ear Mite
• Adult:
◦ 0.4mm
◦ Dorsoventrally flattened
◦ Considered an Arachnid
‣ Has 8 legs
◦ Femals are larger than male mites
• Clinical Signs:
◦ External Otitis
◦ Sticky brown exudate from the ears
• Diagnosis:
◦ Examine debris from external ear canal
• Control:
◦ Clean Ears
◦ Apply miticide
• Lifecycle: 18-21 days
• Life stage: Egg - larval (6 legs) - Nymph (8 legs) - Adults (8 legs)
• Live entire lifecycle on the host
• Spread by direct contact
Cheyletiella spp
• Common Name:
◦ Fur Mites
◦ Walking Dandruff Mites
• Adults:
◦ 0.5mm in length
◦ Have a hook like palpi
• Defenitive Host:
◦ Most cats
◦ Dogs
◦ Can be infest humans which will cause itching but they do not thrive on humans
• Can cause Alopecia dermatitis
• Diagnosised by
◦ Skin Scraping
◦ Cellophane Tape Method
• Control:
◦ Apply Miticide
• Lifecycle:
◦ Spend their entire life cycle on the host
Sarcoptes scabiei
• Common Name:
◦ Mange Mite
• Adults:
◦ 0.3-0.5mm in
◦ Burrows tunnel into the skin
• Causes severe dermatitis
◦ Alopecia
◦ Skin Trauma
◦ Leathery skin texture - dry thickened skin
◦ Ulcers
• Diagnosis:
◦ Deep Skin Scraping
‣ These mites will burrow faster than you can scrape
• Control:
◦ Apply Miticide
◦ Itch Relief medication
◦ Clip Hair
◦ Bathe
• Head, Shoulders & Neck - they like locations where the animal cannot reach
• Definitive Host: Dogs
• Tranmission:
◦ Direct Contact
◦ Zoonotic
◦ Can be transmitted to humans through direct contact which would cause a rash for a short amount of time
Demodex spp
• Considered an: Arachnid
• Considered a Mite
• Common Name:
◦ Follicular Mange Mite
• Adult:
◦ 0.25mm long
◦ Cigar Shaped
◦ Found in hair follicles and sebaceous glands
• Normal Skin Flora until large numbers occur than that is when issues begin to appear
• Causes severe dermatitis
• Diagnosis:
◦ Deep Skin Scraping
• Control/Treatment:
◦ Treat w/ topical or systemic Miticide
◦ A lot of topical flea medications have miticide included to make treating/prevention easier
• Sharpei commonly have Demodex issues especially due to the multiple skin folds
• Often leads to secondary skin infections
• Demodex overgrowth can be caused due to physiologic stress and/or immunosuppressant disorder
◦ Important to address the underlying immunosuppressant disorder
Biting Lice:
• Family: Mallophaga
• Surface Dwellers
• Host specific - lives on the host for their entire lifcycle
• Spread by direct contact
◦ Including bedding
• Can live a short amount of time off the host which is why dealing with infected bedding can transmit the lice
• Considered Insects - 6 legs
Trichodectes canis
• Common Name:
◦ Dog Biting Louse
• Considered an insect
◦ Has 6 legs
• Adults:
◦ 2-4mm in length
• Egg:
◦ 0.5-1mm in length
• Can serve as an intermediate host for: Dipylidium caninum (The Flea Tapeworm)
• Can cause irritation, dermatitis, & rough hair coat
• Diagnosis:
◦ Examine hair coat for adults, nymphs, and eggs ———->
◦ This is where the saying “nit picking” comes from
• Control:
◦ Apply topical insecticide
Sucking Lice:
• Family: Anoplura
• Burrows head into the skin & drinks the extra cellular fluid
• Narrow Engloated headparts
◦ Mouth almost looks like a straw
• The legs have hooks which allow them to hook onto the hair shaft
• Considered insects - Have 6 legs
Linognathus setosus
• Common Name:
◦ Dog Sucking Louse
• Considered insects
◦ have 6 legs
• Adults:
◦ 2-3mm in length
• Egg/Nits:
◦ 0.5-1mm in length
• Can cause irritation, dermatitis, rough hair coat & anemia
• Diagnosis:
◦ Examine hair coast for adults, nymphs, & eggs(Nits)
• Control:
◦ Apply topical insecticide
• Transmission:
◦ Direct contact
2 Family of Ticks:
• Hard Ticks
◦ Family Ixodidae
◦ Have a Scutum which is a hard cutical that almost appears like a shield
◦ Only females engorge
• Soft Ticks
◦ Family: Argasidal
◦ Both male & Females engorge
• Considered Arachnids - 8 legs
• Acariasis:
◦ Infestation of ticks and/or mites
• Blood suckers
Rhipicephalus sanguineus
• Hard Tick so in the family of Ixodidae
• Common Name: Brown Dog Tick
• Adults are 1cm in length
• Causes irritation, anemia & tick paralysis
◦ These ticks have neurotoxins in their saliva which causes the paralysis
• Can transmit different diseases
• Diagnossi:
◦ Finding tick on the skin/hair coat
• Control:
◦ Treat w/ topical antiparasitic
Lyme Disease
• Bacterial Infection
• Lyme disease is caused from a bacteria called: Borrelia burgdorferi
Rocky Mountain Spotted Fever
Tick transmitted disease caused by: Rickettsia rickettsii
Cuterebra spp
“Rabbit bot fly” “Rodent botfly”
Adult is a fly, larval stage sometimes infects domestic animals
Importance🡪 Irritation, tissue damage
Diagnosis🡪 Presence of subcutaneous lump w/ breathing hole for larva
Control🡪 Extraction of larva
Gastrophilus spp
“Bot” “Bot fly”
Adult is a fly, larva is brown and 2 cm, eggs are yellow
Importance🡪 Cause stomach ulcers, “worry factor”
Diagnosis🡪 Eggs on hair of legs and face
Control🡪 Deworm infected horses after 1st killing frost
Siphona spp
• Common Name: “Horn fly”
• Adult fly is 4-5 mm in length & dark-colored
• Importance: Loss of production due to irritation
• Diagnosis: See adult fly feeding on cow
• Control: Apply topical insecticide to animal and premises
Tabanus spp
“Horse fly”
Adults:
Two singled Fly Up to 3 cm
Only females feed on blood
scissor like mouth parts to lacerate skin
Eggs & larva are found around mud & water
Symptoms: Painful biter, “worry factor”, weight loss
Diagnosis: See adult fly bite animal
Hypoderma lineatum common name?
◦ “Cattle bot fly”
◦ ”Cattle grub”
◦ “Warble fly”
Blow Fly definitive host?
Only Sheep
Blow Fly Appearance
•Adult is a fly
◦ Larva is a maggot/grub 1.5 cm
‣ The larva maggot form is called: Grub
Blow Fly can lead to?
myiasis (strike)
‣ Myiasis is also called “Strike”
• The presence of fly larva in flesh.
◦ Fly lays eggs in moist open wound, abrasion, or soiled hair coat. Eggs hatch and larva start feeding on dead cells and exudate.
◦ Larva irritate and injure adjacent tissue leading to formation of subcutaneous pockets
Blow Fly is diagnosed/control & prevention?
Larva in open wound
• Control/Prevention:
◦ Clean wound, apply insecticide
◦ Treat open wound and abrasions
◦ prevent soiling & matting of hair coat
Hypoderma lineatum Appearance?
Adult Larva are 3cm -
Bee like appearance with yellow to orange hairs
Eggs: All in a row deposited on the legs
Hypoderma lineatum causes?
“worry factor” - Painful bite
tissue damage when migrating through the body trying to find the subcutaneous tissue
Hypoderma lineatum is diagnosed, controlled & prevented how?
Diagnosis
◦ Cyst-like swelling w/ breathing hole (warble)
‣ Opening/breathing hole: Fistula
◦ Larva is the problem - also called Warble
Control
◦ Apply topical insecticide
◦ Do not treat until the larva has completed their migration and made it to the subcutaneous tissue - we do not want to treat while they are migrating
treating cows when for Hypoderma lineatum is bad why?
Late fall because it may kill the larva in the esophagus or spinal canal causing inflammation & serious damage in these tissues
Hypoderma lineatum biggest concern is?
the larva penetrate the skin on the legs & migrate through the body until they get to the subcutaneous tissue on the dorsal back causing a lot of damage along the way
Cuterebra spp lifecycle
Egg
Larva
Pupa
Adult
Cuterebra spp larva enter?
Through the mouth and/or nares during grooming or through an open wound. Generally picked up nears nexts or rodent burrows. Stays in host for 1-2 months before appearing like a cyst generally seen in later summer early fall
Rocky mountain spotted fever vector & reservoir?
Tick
Rocky mountain spotted fever transmitted by?
Transovarial
Transtadial
• Disease is most prevalent in South Atlantic states & Midwest
• Once infected, ticks may transtadially spread RMSF among their own population through the transfer of bodily fluids during mating, or transovarially spread the organism from the pregnant female to her offspring.
◦ Transovarial infection is the primary means by which R. rickettsii propagates in nature. Once infected, ticks then transmit RMSF to vertebrates (including dogs and humans) through their saliva when taking blood meals. Generally, an infected tick must be attached to its host from 5 to 20 hours for transmission of R. rickettsii to occur.5 This organism may also be transmitted through contact with infected tick hemolymph or excrement (Fig. 4), especially when engorged ticks are crushed.
Rocky mountain spotted fever syndrome
• Syndrome:
◦ Humans:
‣ fever, myalgia, headache, chills
‣ skin rash on extremities
‣ capillary damage, liver disease
◦ Wild animals:
‣ subclinical
◦ Domestic animals:
‣ fever, anorexia, swollen lymph nodes
‣ dyspnea, abdominal pain, edema of face and extremities
‣ conjunctival bleeding and retina damage
• Incubation Period: 3-14 days
• Mode of tranmission:
◦ Through the bite of an infected tick
‣ Dermacentor variability
• Common Name: American Dog Tick
‣ Dermacentor Andersoni
• Common Name: The Wood Tick
◦ Contact of skin or mucous membranes with tick body fluids when removing it
• Diagnosis:
◦ History of tick bite, rash, & fever
◦ Serology
• Treatment:
◦ Antibiotics
• Control/Prevention:
◦ Wear protective clothing when entering tick habitat
◦ Use tick repellents
◦ Check yourself & your for ticks & remove carefully
◦ Clear brush away from residential areas
Lyme disease vector?
• Tick Vector
Lyme Disease Syndrome
Bacteria is maintained in wildlife reservoirs that cause no apparent clinical disease in infected animals
• Syndrome:
◦ Humans:
‣ Erythema Migrans
• Red Circular papule w/ target appearance - may have multiples
‣ Fatigue
‣ Fever
‣ Headache
‣ Muscle & Joint pain
‣ Arthritis
‣ CNS & Cardiac problems
◦ Chronic conditions/illnesses are said to be have been caused by untreated Lyme Disease
◦ Wild Animals:
‣ Subclinical
◦ Domestic Animals: Fever, Anorexia, swollen lymph nodes, lameness, fatigue
Lyme Disease incubation period?
• Incubation period: 3-32 days of appearance of papule
Lyme disease is transmitted?
• Mode of transmission:
◦ Through bite of an infected Ixodes spp tick
Lyme disease is diagnosed & treated?
• Diagnosis:
◦ History
◦ Syndome
◦ Serology
◦ Culture of blood &/or tissue biopsy
• Treatment: Antibiotics
◦ Patients treated with antibiotics in the early stages of the infection usually recover rapidly and completely.
◦ A few patients, particularly those diagnosed with later stages of disease, may have persistent or recurrent symptoms.
◦ The authors of studies sponsored by the National Institutes of Health have concluded that these patients may benefit from a second 4-week course of therapy and that longer courses of antibiotic treatment are not beneficial.
◦ Longer courses of antibiotics have been linked to serious complications, including death.
• Control/Prevention:
◦ Avoid tick bites
◦ Control ticks around your house
◦ Manage wildlife populations (deer, squirrel)
◦ Seek medical help after tick bites
