VPH - Final 1

drraythe's version from 2016-04-25 13:34

Lyme & Ehrlichia

Question Answer
*What is the organism that czs Lyme Dz?Borrelia burgdorferi
*How do most dogs w/ Lyme present?90% of dogs exposed do not show CS (dz). There can be acute onset polyarthropathy & accompanying pyrexia, though.
MOST SERIOUS LONG-TERM DZS FROM LYME IS... Glomerular dz due to Ag/Ab complexes & cardiac & neurologic dz (rare)
Are there Vx for Lyme for dogs?YES
Is Lyme dz reportable? Notifiable? In animals or people?REPORTABLE IN PEOPLE
What is the MAINTENANCE HOST for Lyme? VECTOR?(NOTE: more detailed later about geographic location, but in general)
HOST: infected wild animal spp.
VECTOR: Density of Ixodidae ticks [hard ticks] (Little transovarian xmission occurs in ticks, although there is transtadial)
How do humans relate to the maintenance cycle of Lyme?Humans are an accidental host but are NOT dead end hosts! (can pass Lyme tranplacentally & sexually)
Describe how the vector for Lyme can vary based on geographic location?EAST COAST: Ixodes scapularis (Deer Tick) - 25-50% of ticks infected
WEST COAST: I. pacificus (Western Black-Legged Tick) - 1-5% of ticks infected
On the EAST COAST what are the main Lyme maintenance hosts?White-footed deer mice (principal reservoirs host) & deer
****How do white-footed deer mice contribute to the maintenance cycle of Lyme in the East?CRUCIAL TO MAINTENANCE! Bc they remain spirochetemic but tolerant to infection (can pass to uninfected ticks)
Explain if/how/whats going on w/ ticks & how they can maintain Lyme?NOT transovarian, but CAN have transtadial xmission from larvae to nymph. So, uninfected larval ticks feed on deermice → become infected nymphal ticks → Nymph infect other deermice & dogs/humans → Infected mice source of infection for naïve larval ticks
How do white-tailed DEER play a role in the maintenance cycle of Lyme?NOT INVOLVED IN LIFE CYCLE!! Don't become spirochetemic enough to infect adult ticks. However, they are food to sustain the tick population, so that's something (they are the main host for Ehrlichia chaffeensis & E. ewingii tho)
Explain the cycle for the WEST coast w/ Lyme dz & how it compares to the East coast cycleBOTH SPECIES OF TICKS are required for infection of humans. This is bc the WOOD RAT & I. neotomae ticks maintain the dz in the area, but this tick RARELY bites humans or dogs. Which means uninfected, I. pacificus ticks, occasionally bite an infected woodrat & the tick then bites horses, dogs, humans (this is why there is much lower infection rate in west coast ticks)
How do humans get Lyme dz?THEY GET BIT BY A TICK!!!! (East coast, Ixodes scapularis (the deer tick) & West coast, I. pacificus). USUALLY the bite is from a nymph which must remain attached for 24 hrs or more to xmit the spirochete
**What is crucial for the xmission of the Lyme spirochete from the tick bite?Takes 24 hours to xmit!!! So IMPORTANT TO REMOVE TICK EARLY ON
Is it possible for Lyme to be xferred human-human?Yes, rare, but transplacental & sexual xmission possible
*How does Lyme dz usually present in humans?Presentation highly variable. Usually flu-like dz - usually 3 BODY SYSTEMS AFFECTED:
Cutaneous (erythema migrans = bullseye lesion which is not always present)
Musculoskeletal (dz usually progresses in stages)
*How can you Dx dogs w/ Lyme?DIFFICULT! Hx of tick exposure helps, along w/ CS:
Swollen joints
- If Tx, there will be RAPID RESPONSE to antimicrobial therapy. Upon serology, a "significant" positive titer as evidence of exposure. Paired titres important for current infection. High antibody titers do occur in asymptomatic dogs!!!!! Important to know infected animal may initially test seronegative
**How do you know if a dog was exposed to Lyme? Infected?Exposure = Elevated Ab titer
Infected = PAIRED titers
What are some common currently used diagnostic tests in dogs?PCR detection (not widely avail)
SNAP tests
C6 Antibody Testing: Currently 2 commercially available tests for canine antibodies against the Lyme C6 peptide.( NOTE: No blood test can confirm Lyme Dz in dogs!!!)
What is meant by a C6 titer?C6 is a peptide on the Lyme organism which you can form an Ab against. Can test for this Ab, look at a titer for it & can tell infection based on pre & post Tx measurements of it. (Quantitative C6 titer drops w/ ABx therapy)
**How do we try to prevent confusion btwn Abs from Vx & Abs from exposure?Traditional ELISA for antibody cannot distinguish: Vx - induced antibodies from antibodies due to natural exposure. B. burgdorferi expresses several [OspA –C] Proteins but only when in the tick gut. These proteins used as Vx antigens. However, another outer membrane protein, **C6 is only expressed ONLY by LIVING B.burgdorferi & is not used as a Vx antigen**. So use C6 as a way to tell if the dog was exposed/infected my the actual organism vs just Vxd
If you test positive for C6 Abs, what does this mean?Dog was EXPOSED/ infected, but the abs are NOT FROM BEING VXd
How are dogs Txd for Lyme?Dogs w/ acute Lyme arthritis respond rapidly to amoxicillin or tetracyclines (doxycycline)-(within 36hrs). Acute cases Tx for 2 wks, chronic for 4wk. (Optimum period/dose not established by clinical trials)
What are you thinking if dogs w/ chronic arthritis doesnt respond to abx Tx?May have immune-mediated polyarthropathy & req. steroids
Why is the Lyme Vx controversial?Most dogs dont get CS of the dz & some question the effectiveness of Vx
What is the rare but most serious canine presentation of Lyme?Lyme nephritis is severe (Screen for proteinuria)
If you Dx Lyme, what else must you consider?Coinfections, bc of being tick bourne & they carry a lot of different dz agents
What is super important to stress to owners about Lyme dz?Even in vaccinated dogs TICK CONTROL must be stressed to the owners since a very heavy B. burgdorferi burden may override vaccinal protection
Is there a Vx for people against Lyme? What should you know?Not really...1 in development, but there are problems: poor demand, costly, Req. series of 3 Vxs/boosters to maintain titers & RISK OF AUTOIMMUNE ARTHRITIS
Prevention & control: Your role on educating clients on what for Lyme?The importance of approved tick control [acaricides that kill ticks] in the environment & tick repellents & EPA approved acaricides for pets. Vx alone or Tx alone is insufficient unless combined w/ vector control measures & advising owners on preventing tick exposure to them & their animals. Ticks carried by dogs (not dogs themselves), are the source & reservoir of infection to humans & it is important that owners are aware of the risks to human health posed by ticks that may carry multiple zoonotic agents
What are the 4 species of zoonotic Ehrlichia?Ehrlichia chaffeensis
Ehrlichia ewingii
Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila)
E. canis ( ← not really)
What are the 4 main tick born dzs in cats?Anaplasma phagocytophilum
Cytauxzoon felis
F. tularensis - zoonotic
Ehrlichia spp
(Ticks are also a possible vector of Bartonella spp.)
What is the Ehrlichia agent maintenance cycle like?Agents maintained w/in a tick – wild animal cycle
What are the biological vectors of Ehrlichia/Anaplasma sp? (3)Hard ticks (family Ixodidae) of Genera → 3 spp:
(1) Amblyomma spp
(2) Dermacentor spp
(3) Ixodes spp. **human dzs in the United States
E. chaffeensis - main host?White-tailed deer (deer chaffed me last night, we went mono-e-mono)
E. ewingii - main host?Deer mainly but possibly Dogs also
A. phagocytophilum - main host?Cervids (deer) & rodents reservoir hosts
What are the accidental, dead-end hosts for Ehrlichia/Anaplasma species & how do they get infected?Humans, dogs
Via tick bite
What czs Human Monocytic Ehrlichiosis?E. chaffeensis (a deer chaffed me, we went mono-e-mono)
What czs Human Ehrlichiosis?E. ewingii (deer/dogs)
What czs Human Granulocytic Ehrlichiosis?Anaplasma phogocytophylum (horse 1) (GEAP!!!)
How do you Tx Ehrlichia/Anaplasma sp?The drug of choice for all forms of Ehrlichiosis is Doxycycline or other tetracyclines
Is there dog-human xmission of Ehrlichia?While there are no reports of direct dog-to-human xmission of either E. ewingii or E. chaffeensis, identification of an infected pet would suggest the pet’s owner is at risk of exposure to infected ticks

Immunocompromised ppl & their pets

Question Answer
What is Immunosuppressed (IS)? What are the 2 types?A state in which the immune system is suppressed
(1) Artificial: (by steroids/drugs during the Tx of: Autoimmune dzs, Organ xplantation)
(2) Natural: Age, Pregnancy
**Clinical definition of AIDS?2 things reqd for this dx:
(1) HIV
(2) Has 1 of the following AIDS-defining zoonoses:
Cerebral Toxoplasmosis
Chronic Cryptosporidiosis

(both parasites - they are toxic for the HIV PTxs crypts of the body)
3 common modes of pet-human xmission?Bites
Exposure to saliva & secretions: urine, feces
**What are some BACTERIAL zoonoses which IS or IC ppl are esp. at risk to?Pasteurella multocida
Capnocytophaga canimorsus
Mycobacterium marinum
Salmonella spp
Campylobacter spp
Bordetella Bronchiseptica
Rhodococcus equi
Bartonella henselae

(Sal & Cap'n Bart Borded their dog & Camped on the Rhod Passed Myco's Marina)
What is the main VIRAL zoonoses assoc. w/ IS & IC persons?Lymphocytic Choriomeningitis virus [LCM]
What are the main 3 PROTOZOAL zoonoses assoc. w/ IS & IC persons?Toxoplasma gondii
What are the main 3 MYCOTIC zoonoses assoc. w/ IS & IC persons?Dermatophytes
Cryptococcus spp
Sporothrichium spp
(& other fungi) (shitty damn crappy fungi)
What should you know about Vx & IC ppl?They are a risk to IC ppl
Where is Pasteurella multocida usually found? How is it usually xmitted?Normal microflora of oral cavity of domestic carnivores
Xmission via: bites or scratches, aerosol, saliva & other animal secretions (pasture in the mouth of
How does pasturella often affect IC PTxs?Systemic infxns in IC PTx → deep cellulitis (in mouth of carnivores, so bites, so get into the cellulite, so cellulitis)
Capnocytophagia canimorsus is usually found where? How is it xmitted?Component of oral microflora of domestic carnivores. Xmitted via bites or aerosol from animal → humans
How does Capnocytophagia canimorsus affect IC PTxs?In IC PTx, septicemia → mortality rates up to 33%.
Mycobacteria marinum is usually found where/what is the reservoir? How is it xmitted?Lives in aquatic environments. Both fresh & salt water are the reservoir. Humans usually become infected after areas of minor trauma are exposed to contaminated water
**How does Mycobacteria marinum affect IC PTx?They develop cutaneous lesions → "swimming-pool granuloma" or "fishtank granuloma”. Can be disseminated infxns which may be unresponsive to Tx
How can IC patents avoid Mycobacterium marinum?All cases w/ AIDS parents was from an aquarium. Tell them to wear gloves when cleaning aquarium, or have someone else clean it
Rhodocococcus equi → where is this found? How can IC PTxs get infected?No vertebrate reservoir reqd!! Ppl & horses can get it from the environment (Soil). Pathogenic to foals when inhaled in dust & they get pneumonia, BUT HORSES NOT ESSENTIAL FOR HUMAN INFXN. Usually IC PTxs infected via inhalation/aerosol
**How does Rhodococcus equi affect IS PTxs?Develop pneumonia from inhaling in from the enviro (SOIL)
How can IC patents avoid Rhodococcus equi?Ubiquitous bacteria, especially in equine environment where herbivore manure & warm temps appear to provide ideal conditions for multiplication & infected foals may shed larger #s in feces. So, avoid farms w/ cases in foals. These farms will have ↑ numbers of organism in the environment
What are the 2 most common strains of Salmonella in AIDS PTxs?S. typhimurium
S. enteritidis
(typhoid sally w/ diarrhea is an AIDS PTx's worst nightmare)
How is Salmonella usually xmitted?Xmission via:
Contaminated food
Environment, Soil or fomites
How can animals infected w/ Salmonella present?Can be asymptomatic or diarrhea
What is a known source of Salmonella in children?Contact w/ reptiles in particular pet turtles, are a DIRECT EXPOSURE & source of infxn to children thus FDA ban on the interstate shipment of pet turtles. Can come from other pet reptiles, cats, birds, rodents
How does Salmonella present in an IC PTx?In HIV infected PTx, Salmonellosis is characterized by a recurrent diarrhea, frequently associated w/ septicemia/more severe dz w/ systemic involvement
Which 2 Campylobacter sp are the leading cz of human enteritis?C. jejuni
C. coli (camping w/ intestines)
Which Campylobacter is most frequently associated w/ systemic dissemination, especially in IC PTx?C. fetus (them babies all up inside of you...AHHH)
How are Campylobacter species usually spread to humans? (2)Contaminated or undercooked meat
Young, diarrheic pets, shed it & pose a risk to owners
What is dz czd by Campylobacter like?Localized to GIT or further systemic involvement…Guillain-Barre (rare disorder in which your body's immune system attacks your nerves) (I camped w/ a chick that had Guillain-Barre once)
How do humans acquire Bordetella bronchiseptica & what is the dz like in ppl?It may cz respiratory infxns in IC humans, mostly following direct exposure to infected animals
Bartonella henselae → what dz does this cz in NORMAL ppl, what dz does this cz in IC ppl?Normal ppl: Cat Scratch Dz (I almost died from this when I was 11)
IC ppl: Bacillary Angiomatosis
What czs Bacillary Angiomatosis & who gets it?IC ppl get it, czd by Bartonella henselae (get BA not cat scratch)
What is Bacillary Peliosis?This is when Bacillary Angiomatosis in IC ppl moves on to vascular prolif in INTERNAL ORGANS
**How does Bacillary Angiomatosis present in IC ppl?(From Bartonella) Cutaneous (SKIN DZ) papules & nodules
*What is the 1° reservoir for Bartonella henselae? How can it be xmitted to ppl?Cats are thot to be 1° reservoirs. Xmission not known but positive association w/ cat bite or scratch, OR owning a kitten (<1 yr old) w/ fleas; DIRECT EXPOSURE
**Best advice to avoid Bartonellosis is...(2)(1) Flea control for the cat
(2) Avoid cat bites & scratches (esp from very young cats - Advise against IS ppl keeping young cats) be hygienic!
Why is it so hard to get rid of Bartonella from a cat? (2)Both Intraendothelial & Intraerythrocytic phases of infxn: found inside cat RBC’s