Block 6 Flashcards
Cell Wall
what is it
purpose
Cell wall: PEPTIDOGLYCAN, for shape and structure, used to determine if gram pos. or gram neg.
thick peptidoglycan layer, no outer membrane, lipoteichoic and teichoic acids, strong antigenic properties
* More resistant to drying and disruption
* GRAM STAIN: purple=positive
gram + or -?
Gram pos
thin peptidoglycan layer, has outer membrane, lipopolysaccharides (aka LPS)
* More prone to drying and disruption (because more lipids)
* Polysaccharide chain: antigenic portion
* Lipid A: endotoxin that will cause toxic effects (harm) and activate immune system
* GRAM STAIN: pink=negative
gram + or-?
Gram neg
Do all bacteria have cell wall?
All bacteria have this except mycobacterium (mycolic acid virulence factor) à acid fast stain
* ACID FAST STAIN: pink=positive, blue=negative
Which bacteria are acid fast partial?
corynebacterium
rhodococcus
nocardia
Mycobacterium overview
non-spore forming, non-motile, rod shaped
defines what?
Aerobic
Mycobacterium overview
Acid fast stain (ZN) due to the lipids and mycolic acid in the cell wall:
what result Acid fast?
What relavance gram pos?
acid fast pos. (stain pink)
Gram pos. but will not gram stain because of the mycolic acid
Mycobacterium overview
The lipid rich cell wall make this bacteria….(3 things)
- hydrophobic (hates water)
- resistant to an adverse
environment (AKA they are more resistant than other bacteria) - susceptible to pasteurization
Mycobacterium overview
Environmental saprophytes that can be divided into…what?
opportunistic bacteria or obligate pathogens
Mycobacterium overview
Disease is typically chronic and progressive, and the major diseases include: name 3
- Tuberculosis (TB), Johne’s disease, feline leprosy
Mycobacterium overview
Some diagnostic procedures:
hint:
* use of biohazard cabinet
* obligate/saprophyte graowth rate
* BACTEC
* culture for?
* PCR for?
- Use a biohazard cabinet as a safety precaution!
- Obligate pathogens will grow slowly on enriched media while saprophytes grow fast
-
BACTEC: commercial liquid culture used to improve isolation time of pathogenic mycobacteria to10-20
days - Culture to check for viable bacteria, then PCR from culture and/or clinical samples to ID the species
Pathogenic Mycobacterium summary
M. tuberculosis
- Main host?
- Occasional infected?
- Disease?
- Significance of
infection - Growth rate/temp.
- Growth supplement
- Humans, primates
- Dogs, cattle,
psittacine birds, etc. - Tuberculosis
(worldwide) - Humans
Zoonotic! - Slow
37oC
Pathogenic Mycobacterium summary
M. bovis
- Main host?
- Occasional infected?
- Disease?
- Significance of
infection - Growth rate/temp.
- Growth supplement
- Cattle
- Deer, badgers,
opossum, humans,
cats, etc. (problem in
wildlife) - Tuberculosis
- Cattle
Zoonotic! - Slow
37oC
Pathogenic Mycobacterium summary
M. avium complex
- Main host?
- Occasional infected?
- Disease?
- Significance of
infection - Growth rate/temp.
- Growth supplement
- Most avian species
(not psittacine) - Pigs, cattle, humans
- Tuberculosis
- Poultry
Zoonotic! - Slow
37oC-43oC
Pathogenic Mycobacterium summary
M. lepraemurium
- Main host?
- Occasional infected?
- Disease?
- Significance of
infection - Growth rate/temp.
- Growth supplement
- Rats, mice
- Cats (get bit by
mouse, rat) - Rat leprosy, feline
lepsrosy - does not grow
Pathogenic Mycobacterium summary
M. avium subsp.
paratuberculosis
* Main host?
* Occasional infected?
* Disease?
* Significance of
infection
* Growth rate/temp.
* Growth supplement
- Cattle, sheep, goats,
deer - Other ruminants
- Paratuberculosis AKA
Johne’s disease - Ruminants
- Very slow (up to 16
weeks)
37oC - Mycobactin (important for growth
Reemerging, granulomatous disease
in animals and people that is chronic
and debility
* Signs and lesions (granuloma) are
similar in the various species
what is it?
Tuberculosis
*marcophages cannot digest
* world wide
Bovine TB
why is it important?
specifically where?
relevence for some wildlife species?
Bovine TB is an important zoonosis
(especially in non-industrialized
countries) and is **endemic **in some
wildlife species
M. tuberculosis (Mtb) complex
What is it composed of?
example?
M. tuberculosis (Mtb) complex is
composed of closely related species,
including but not limited to M. bovis
and M. tuberculosis
Tuberculosis
where and how can they live? for how long?
These bacteria can survive months in
the environment (cold, dark, moist
conditions)
M. tuberculosis is an emerging zoonosis and Anthropozoonosis
T/F
T
? is maintained in nature by animals and is transmissible to
humans
Zoonosis
Endemic infections in wildlife populations include:
name 2
- Banded mongoose in Botswana
- Suricates in South Africa
Tuberculosis
Reservoir: ?
Reservoir: humans!
Tuberculosis
Susceptible species:
7
Susceptible species: dogs, cats, pigs, nonhuman primates,
psittacine birds, canaries, elephants
Tuberculosis
Disease in humans is considered ?
NOTIFIABLE
Tuberculosis
Pulmonary disease is more common with what type of infections
Pulmonary disease is more common with reactive infections
Tuberculosis
Disease in humans, specifically children may display?
Children: cervical lymphadenopathy, tonsillar and pre-auricular
LN’s
Tuberculosis
what effect to skin?
Localized skin disease that is benign and self-limiting
Tuberculosis
Genitourinary disease can cause what?
kidney failure
Bovine Tuberculosis
M. bovis is found where? and is a NOTIFIABLE disease (indistinguishable from M. tuberculosis in humans)
Is it zoonotic?
what result?
worldwide
Zoonotic implications and economic loses
Bovine Tuberculosis
what is the global status?
what about the US?
Is any country TB free?
TB status: widespread TB, eradication programs in progress (U.S.), TB free countries (Canada)
Bovine Tuberculosis
Reservoir: ?
result?
relevance?
example in UK/Ireland?
New Zealand
Michigan?
wildlife, therefore eradication is very difficult to achieve, also survives well in the environment
- UK and Ireland: badgers
- New Zealand: opossum
- Michigan: white-tailed deer
Bovine Tuberculosis
- Susceptible species and transmission
what type of host and carrier are cattle?
how are they infected?
- Cattle are **reservoir hosts **and asymptomatic carriers: typically infected via aerosol but also, ingestion, cutaneous, genital,
and congenital
*aerosol: only need 10 particles to transmit
Bovine Tuberculosis
Susceptible species and transmission
Humans?
Humans: mostly by ingestion of unpasteurized dairy products or undercooked meat, but also, aerosol (from cow), breaks
in skin, person-to-person (immunosuppressed)
Bovine Tuberculosis
Susceptible species and transmission:
Cats?
Cats: ingestion of raw milk, aerosol, bite/scratches
Bovine Tuberculosis
Susceptible species and transmission
Pigs/ferrets/deer
ingestion
Bovine Tuberculosis
Susceptible species and transmission
Badgers
bites/scratches
Bovine Tuberculosis
Virulence factors:
lipids in the cell wall allow the bacteria to survive/multiply host macrophages
Bovine Tuberculosis
Cell protein antigens:
tuberculin
Bovine Tuberculosis
Pathogenesis:
type IV hypersensitivity reaction resulting in granuloma formation
Bovine Tuberculosis
Pathogenesis:
Following infection, how does the bacteria survive?
Following infection, bacteria is engulfed by macrophages (and dendritic cells), but the cell wall glycolipid blocks
phagosome-lysosome formation allowing for bacterial survival
Bovine Tuberculosis
Pathogenesis
Infected macrophages secrete cytokines
why?
what result?
Infected macrophages secrete cytokines to recruit lymphocytes to help, but the lymphocytes help contain the
bacteria and then secrete cytokines to recruit more macrophages
Bovine Tuberculosis
Pathogenesis
There is gradual accumulation of macrophages
resulting in what?
what can be found at the site of the granuloma?
how long does this process take?
There is gradual accumulation of macrophages around a lesion with a central necrotic core = tubercle or
granuloma which is the typical host response
* Macrophages, lymphocytes, and fibroblasts will all be found at the site of a granuloma
30 days
Bovine Tuberculosis
Pathogenesis:
Rupture of a granuloma allows for what to occur?
Rupture of a granuloma allows infected macrophages to leave and migrate, which results in dissemination and
spread to other parts of the body
Bovine Tuberculosis
CS in cattle
when can it be observed?
what result?
- CS in cattle can only be seen in advanced disease: loss of condition, cough and pyrexia, mastitis
- Lesions: caseous necrosis (soft cheese like consistency) within a capsule formation
Bovine Tuberculosis
- Dx: name 4
- Tuberculin skin test
- Sample LN’s
- Gamma interferon
- ELISA
Bovine Tuberculosis
Dx:Tuberculin skin test
why?
how is it done?
what is the preliminary screening?
what is a comparitive cervical?
how is it done?
what causes a false positive
what causes a false negative?
- Tuberculin skin test is done on live cattle to look for a cellular response:
- Purified protein derivative (PPD) prepared from tuberculin, is injected intradermally to detect sensitization/reaction
- Preliminary screening: injection in caudal fold, view at 72 hours to look for thickness/swelling and IF POSITIVE,
- Comparative cervical: retesting of reactors with bovine PPD and avian PPD, view at 72 hours and if the bovine PPD injection site exceeds the
avian PPD by 4 mm or more = a REACTOR - Cervid screening: single cervical injection using bovine PPD
- False positive: can occur if there is another bacteria present besides M. bovis, this is why we re-test positive results
- False negative: if an animal has been infected within the last 30 days, anergy (unresponsive state) with advanced infections,
transient desensitization (retest at 60 days), immunosuppression
Bovine Tuberculosis
Dx:
Sample LN’s, tissue lesions, aspirates or milk to perform
how?
to detect what?
how long for result?
Sample LN’s, tissue lesions, aspirates or milk to perform microscopy with acid fast stain, culture with BACTEC, or PCR
for detection and ID (results in 1-2 days)
Bovine Tuberculosis
Dx:
Gamma interferon
what is it good for?
what result?
Gamma interferon: good for herd screening, detect infection at an earlier stage
Bovine Tuberculosis
Dx:
ELISA
when should you use it?
later stages of infection
Bovine Tuberculosis
Tx: ?
- Tx: none, test and cull, no vaccines available
Bovine Tuberculosis
Prevention:
Prevention: screening herds, rodent control, sanitation/disinfection
Avian tuberculosis
found where?
zoonotic?
M. avium complex (serotype 1-3) is found worldwide in many species
* Zoonotic: infection in immunocompromised people
Avian tuberculosis
- Susceptible species:
wild and domestic birds but most common in free-range adults, companion
animals, captive exotics
* Pigs can be infected by ingesting uncooked swill- causes small tubercles in the LN’s
Avian tuberculosis
Transmission:
fecal-oral route
* Bacteria are excreted from the feces of birds with advanced lesions and the organisms survive well in the soil
Avian tuberculosis
CS:
CS: dullness, emaciation, lameness
* Can see granulomatous lesions at post-mortem in the liver, spleen, bone marrow, and intestines
Avian tuberculosis
Dx:
Dx:
* Avian PPD tuberculin injection into the skin of the wattle of live animals
* Post-mortem findings + positive bacilli in smears with ZN stain + confirmation with PCR
Johne’s disease, Paratuberculosis, MAP
Mycobacterium avium subsp. paratuberculosis (MAP) is
It is economically important because?
Mycobacterium avium subsp. paratuberculosis (MAP) is a chronic and contagious, fatal enteritis of domestic and wild
ruminants
* Economically important disease due to the monetary losses, especially from drop in milk yields
Johne’s disease, Paratuberculosis, MAP
Susceptible species:
cattle, sheep, goats, llamas, deer
Johne’s disease, Paratuberculosis, MAP
Risk factor:
Risk factor: feeding pooled colostrum
* Combination of colostrum from several cows that is combined into a vat- one positive cow will infect the entire pool of colostrum
Johne’s disease, Paratuberculosis, MAP
Transmission:
Transmission: fecal-oral route, bacteria are excreted in the feces (in large #’s), or ingestion of milk and colostrum (in lower #’s)
Johne’s disease, Paratuberculosis, MAP
Transmission:
cattle?
- Cattle are infected early in life, but the progression of disease onset is very slow so CS will not develop in cattle less than 2 years of
age and they could potentially be shedding more bacteria during this time - Cattle exposed as adults are less likely to become infected because resistance develops with age
Johne’s disease, Paratuberculosis, MAP
Transmission:
Introduction of the disease into a non-infected herd will be due to ?
Introduction of the disease into a non-infected herd will be due to replacement animals/herd expansion and those new cattle
coming in with a sub-clinically infected carrier
* A sub-clinically infected carrier will also maintain disease in a herd
Johne’s disease, Paratuberculosis, MAP
Pathogenesis:
following ingestion what happens?
Pathogenesis: following ingestion bacteria will be uptaken into the Peyer’s patches of the lower SI and infect macrophages in
the GI tract and associated LN’s
* Bacteria will multiple and induce a chronic granulomatous enteritis that interferes with the uptake of nutrients which eventually will
cause cachexia
Johne’s disease, Paratuberculosis, MAP
CS in cattle:
Progression?
CS in cattle: persistent diarrhea, progressive weight loss, debilitation, eventually death
* Progression: more severe diarrhea, more weight loss, coat color can fade, protein loosing enteropathy will cause edema in the ventral and intermandibular areas, emaciation, death
Johne’s disease, Paratuberculosis, MAP
Pathological lesions:
describe
histo?
microscopy?
Pathological lesions:
* Thickened and corrugated intestine with enlarged and edematous LN’s, typically the distal SI wall is thickened
* Histo: diffuse granulomatous enteritis with epitheliod macrophages (activated macrophage that resembles epithelial cells), from the mucosa and submucosa of the gut
* Microscopy: acid fast positive organisms within macrophages
Johne’s disease, Paratuberculosis, MAP
Dx:
* Live animal: ?
* Post mortem: ?
DO NOT USE what? why?
- Live animal: fecal sample, scraping or pinch biopsy from the rectum
- Post mortem: direct acid fast stain (always start with this!), confirm with culture (BACTEC) or PCR
- DO NOT USE serology (ELISA, gamma interferon assay) b/c not reliable
Johne’s disease, Paratuberculosis, MAP
Tx:
none, test and cull
Johne’s disease, Paratuberculosis, MAP
- Prevention:?
In problem herd:?
- Prevention: fecal sample testing and PCR to look for sub-clinically infected animals (challenging)
- In problem herd: hygiene and husbandry to protect calves and prevent new infection
- Separate calves from the cow at birth and hand raise on pasteurized milk (M. bovis bacteria are killed, but risk of the calves not building
immunity to other pathogens), keep the calves away from herd for at least 2 years
Feline leprosy
what is the name?
where is it found?
what does it cause?
zoonitic?
M. lepraemurium is found worldwide and causes a cutaneous disease
* NOT zoonotic or infectious to other animal species
Feline leprosy
Reservoir:
Transmission:
- Reservoir: rodents
- Transmission: bites from infected rodents
Feline leprosy
CS:
CS: subcutaneous nodules that are freely movable and typically ulcerate (but not always), found on the
region of the head and/or the limbs
Feline leprosy
Dx:
what relevance is a culture?
Dx: smear from lesion stained with ZN and look for positive rods, histopathological features, PCR, negative
culture from M. bovis (and other opportunistic bacteria)
- M. lepraemurium does NOT grow on culture, so if you suspect a cat is infected then perform a culture, if there is
growth then the cat would actually be positive for M. bovis
Richettsiales overview
what is it? define
do you culture?
- Gram neg. small, non-motile, pleomorphic and OBLIGATE
INTRACELLULAR bacteria that effects blood and endothelial cells - Culturing is not used for diagnostics and has to be done in select tissue
culture or yolk sac of embryonated eggs, stain with Giemsa or diff quick
Richettsiales overview
2 genera: what are they?
2 genera: Orientia and Rickettsia
* Genus Rickettsia is further divided into Spotted Fever Group and Typhus
Group
Richettsiales overview
what kind of disease is this?
who gets it?
is it zoonotically important?
how transmitted?
Arthropod vector borne disease in animals and humans, zoonotically
important
* Resides in a wide range of arthropods (fleas and ticks are the most
common) and is transmitted via the arthropod bite, arthropod feces
inoculation (ex. flea feces in a wound) or inhalation
Richettsiales overview
Reservoir: ?
Susceptible species: ?
Reservoir: rodents and small mammals
* Susceptible species: humans, dogs, etc.
Richettsiales
Rocky Mountain Spotted Fever
who gets it?
what are the 2 cycles called?
R. rickettsi causes infection in humans, dogs, and other species of
animals
* **Domestic cycle **between humans and dogs and **sylvatic cycle **in wild animals
(very important)
Richettsiales
Rocky Mountain Spotted Fever
Reservoir:?
Transmission:?
- Reservoir: rodents and small mammals develop high levels in their blood
- Transmission: Dermacentor andersoni (Rocky Mountain wood tick) and
Dermacentor variabillis vectors
Richettsiales
Rocky Mountain Spotted Fever
Pathogenesis:
Pathogenesis: damage to the endothelial cells initiates vasculitis with
platelet activation, this is followed by thrombocytopenia and ultimately
causes DIC and necrosis
Richettsiales
Rocky Mountain Spotted Fever
CS: ? dogs?
CS: dogs can have clinical or subclinical infections
* Fever, depression, anorexia, subcutaneous edema, petechia on mucous
membranes, pain
* Clinically appears like Canine Ehrlichiosis (AKA the CS are very similar between the 2
diseases)
Richettsiales
Cat-Flea Typhus-like illness
who gets it?
how widespread?
is it zoonotic?
R. felis causes disease in cats
worldwide, zoonotic with people
being an incidental host
Richettsiales
Cat-Flea Typhus-like illness
Domestic cycle is maintained how?
sylvatic cycle is found where?
- Domestic cycle is maintained in
asymptomatically infected cats - Sylvatic cycle is found in
opossums
Richettsiales
Cat-Flea Typhus-like illness
Transmission: ?
CS in humans:
- Transmission: C. felis
- Human transmission is not
understood - CS in humans: cutaneous flea
bite reactions, fever, pain,
hyperesthesia (abnormally
sensitive to stimulus),
maculopapular rash
Richettsiales
Murine Typhus
where is it found?
is it zoonotic?
domestic and/or sylvatic?
- R. typhi is found endemically in s**outhern
California and South Texas **and is zoonotic - Domestic and sylvatic cycles
- Reservoir: rodents, opossum, cats
Murine Typhus
Transmission:
what is unique about dogs?
CS in humans:
- Transmission: C. felis and Xenopylla (rodent flea)
- Infected flea feces and scratched into a wound
(bite wound) - Dogs can be effected by C. felis but they
**CANNOT **get infected with Murine typhus
CS in humans: eschar (dark scab) and lymphadenomegaly (skin lessions)
Richettsiales
Murine Typhus
Diagnosis, treatment, prevention?
- Diagnosis:
- CS and flea/tick exposure
- ELISA, IFI, agglutination: serology is the most useful
but cross-reaction between species is possible
(Typhus groups and Spotted fever group) - Culture and isolate: BSL3
- PCR is useful in reservoirs and vectors, bacteria loads
can be too low in a host - Treatment: Tetracycline, Doxycycline,
Chloramphenicol, Enrofloxacin - Prevention: flea and tick control
Anaplasmataceae
what is it?
Obligate INTRACELLULAR aerobic
organisms that parasitize the cell and
form a **morula **or cluster of bacteria
* Leukocytes, erythrocytes, platelets,
endothelial cells
Anaplasmataceae
Host species: ?
Reservoir: ?
Transmission: ?
- Host species: humans and domestic
animals - Reservoir: sylvatic cycle in wildlife
- Transmission: tick vectors or
trematodes (Neorickettsia) - Anaplasma, Ehrlichia, Neoehrlichia,
Neorickettsia
Anaplasmataceae
Granulocytic Anaplasmosis
what is it?
what does it cause?
who does it affect?
how does it affect?
Anaplasma phagocytophilum causing Granulocytic Anaplasmosis in
humans, dogs and other domestic species (horses, European cattle,
sheep, goats, llamas, cats)
* Mostly effects **neutrophils, **but maybe eosinophils also
Anaplasmataceae
Granulocytic Anaplasmosis
Reservoir: ?
Amplification: ?
Transmission: ?
Pathogenesis: ?
CS: ?
DDx: ?
- Reservoir: small mammals and deer
- Amplification: migrating birds (fly to different areas carrying ticks)
- Transmission: Ixodes tick vector
- Pathogenesis: the bacteria enter the neutrophil and impair the
phagocytic activity, also causes thrombocytopenia (decreased platelet count) - CS: can be self limiting or cause…
- Fever, lethargy, headache (humans), musculoskeletal pain
- Horses: mild and subclinical edema in the limbs, ataxia, DIC can lead to
rapid fatality - DDx: Lyme disease in dogs
Anaplasmataceae
Canine Cyclic Thrombocytopenia
what is it?
who gets it?
symptoms?
Anaplsama platys causes infection in dogs that
are often asymptomatic, but acute infections
can occur
Anaplasmataceae
Canine Cyclic Thrombocytopenia
Transmission: ?
Pathogenesis: ?
CS: ?
Transmission: Rhipicelphalus sanguineus vector (kennel tick)
* Pathogenesis: bacteria enters a platelet and
forms a morula, parasitemia will cause
thrombocytopenic episodes at 1-2 weeks
intervals
* AKA platelets get infected and die, bone marrow
makes more platelets, they also get infected and
die and this cycle continues
* CS: fever, petechia, ecchymosis
Anaplasmataceae
Bovine Anaplasmosis
what is it?
cows v calves?
Anaplasma marginale and Anaplasma centrale
cause inapparent disease in endemic areas
(animals are persistently infected for years)
* Calves are often carriers and more resistant to disease
than older cattle
Anaplasmataceae
Bovine Anaplasmosis
Transmission: ?
CS: ?
Tx: ?
Prevention: ?
- Transmission: via vectors like Boophilus tick or biting
flies, also blood contaminated fomites - CS: fever, anemia, icterus,
- Up to 50% mortality rate in naïve cattle
- Tx: long acting oxytetracycline
- Prevention: testing, cull carrier animals, minimize
stress, vaccinate
Q
Kennel tick
Canine Monocytic Ehrlichiosis
what is it?
when does it occur?
where does it occur?
Ehrlichia canis is found worldwide and infection typically occurs during the warm season when ticks are abundant
Canine Monocytic Ehrlichiosis
Reservoir: ?
Transmission: ?
Pathogenesis: ?
- Reservoir: domestic dog, coyote, fox, jackel
- Transmission: Rhipicephalus sanguineus vector
- Pathogenesis: ticks acquire the infection by feeding on an infected dog, the tick feeds on a new animal and the
pathogen will invade the host cells and replicate in vacuoles where they are protected from the host immune system
Canine Monocytic Ehrlichiosis
Hematological changes:
explain Anemia/hyperglobulimenia
thrombocytopenia
pancytopnia
- Anemia and hyperglobulinemia (increase proteins) due to the infection triggering the inflammatory and immune
processes - Thrombocytopenia: immune mediated destruction and decrease in half-life, overall platelet consumption
- Pancytopenia: decrease in all cell lines due to bone marrow suppression in the chronic phase
Canine Monocytic Ehrlichiosis
cs ?
explain
Acute?
Subclinical?
Chronic?
dx?
cs: multisystemic disorder when acute, subclinical and chronic phases can be observed
Acute: lasts about 4 weeks and will have thrombocytopenia, fever, lymphadenopathy, spenmegany, ocular and nasal discharge.
subclinical: intermittent fever, thrombocytopenia and anemia that last months to years.
Chronic: fever, lymphadenopathy, splenomegaly, ocular and nasal discharge, neurologic signs, petechia, edema, potentially fatal
dx: PCR during acute infection, serolory for subclinical infection.
Ehrlichia & Diagnosis, treatment & prevention for Ehrlichia & Anaplasma
Granulocytic ehrlichiosis
what is it?
host?
reservoir?
transmission?
- Ehrlichia ewingii causes anemia,
thrombocytopenia, and hyperglobulinemia - Acute lameness or polyarthritis
- Host species: humans and dogs
- Reservoir: white tail deer
- Transmission: Ambylomma americanum vector
- affects neutrophils
Ehrlichia & Diagnosis, treatment & prevention for Ehrlichia & Anaplasma
Human monocytic ehrlichiosis
what is it?
reservoir?
transmission?
- Ehrlichia chaffeensis causes thrombocytopenia,
leukopenia, fever, headache and pain
* Reservoir: white tail deer - Transmission: Amblyomma americanum vector
Ehrlichia & Diagnosis, treatment & prevention for Ehrlichia & Anaplasma
Diagnosis, treatment, prevention
exposure to what?
serology used for what?
PCR used for what?
what should you NOT use?
how do you treat? for how long?
- Diagnosis:
- Tick exposure, CS and lab findings in endemic areas
- Cytology of blood smear or tissue aspirates
Ab* Serology (IFI, ELISA) is good for subclinical and
chronic infection, cross-reactivity between bacteria
can occur
Ag* **PCR **of blood or tissue is the preferred method to
confirm infection - Do NOT use culture (time and costs)
- Treatment: 28 days of Doxycylcine, transfusion is
severely anemic - Prevention: tick control
Neorickettsia spp.
Potomoc Horse Fever
what is it?
when does it occur?
where does it occur?
*neorickettsia bacteria in trematode in snail/arthropod–>fish–>host
Neorickettsia risticii is commonly seen from June to
October (seasonal) and is associated with pasture
bordering rivers
* Disease effects enterocytes and monocytes
Neorickettsia
Potomoc Horse Fever
Transmission: ?
Pathology: ?
Dx: ?
Tx: ?
Prevention: ?
- Transmission: horses drink water containing aquatic insects or snails that are infected with metacercaria
(trematode vector) - Fresh water snails and trematodes, caddieflies, mayflies
- Pathology: hemorrhagic enterocolitis
- CS: colic, fever, severe diarrhea, anorexia, severe
leukopenia, laminitis, abortion - Dx: PCR of blood or feces
- Tx: early diagnosis and Oxytetracycline
- Prevention: turn off barn lights to not attract insects that could potentially be ingested, vaccination
Neorickettsia
Salmon Poisoning Disease
what is it?
host species?
transmission?
CS?
Dx?
Dx?
DDx?
Tx?
Prevention?
Neorickettsio Helminthoeca causes desease that will effect the hosts monocytes
* Host species: dogs, polar bears, raccoons, coyotes
* Reservoir: snail
* Transmission: ingestion of raw salmon infected with
the trematode vector
* CS: fever, depression, anorexia, vomiting,
dehydration, hemorrhagic diarrhea,
lymphadenopathy, death in 90% of untreated
dogs
* Dx: fluke eggs, PCR for bacteria in feces, history & geographical location, oregon area
* DDx: Canine parvovirus infection
* Tx: Tetracycline and Praziquantel
* Prevention:** avoid feeding infected fish, snail
control**
Bartonella overview
what is it?
where do you find it?
who gets it?
what is unique about it?
- Gram neg., small, curved bacilli to coccobacilli, pleomorphic, aerobic,** fastidious growth**
- There are several species and subspecies within the Bartonella genus and prevalence is greatest in warm
and humid climates - A large variety of mammals can become infected, but Bartonella are highly adapted to preferential
mammalian reservoir hosts or adapted host (AKA the bacteria will evolve with a specific host)
*hide from host in erythrocytes
Bartonella overview
what is it?
where do you find it?
who gets it?
what is unique about it?
- Gram neg., small, curved bacilli to coccobacilli, pleomorphic, aerobic,** fastidious growth**
- There are several species and subspecies within the Bartonella genus and prevalence is greatest in warm
and humid climates - A large variety of mammals can become infected, but Bartonella are highly adapted to preferential
mammalian reservoir hosts or adapted host (AKA the bacteria will evolve with a specific host)
*hide from host in erythrocytes
Bartonella overview
- Bartonella species specifics:
what does it induce?
unique feature regarding host infection?
what relevance specific or incidental host?
is it syptomatic?
what relevance endocarditis?
what relevance zoonitic?
- Bartonella species specifics
- B. henselae induces **neovascularization **(multistep process of making new blood vessels)
- Once a host has been infected with a particular strain of Bartonella, the host is immune to reinfection of a
homologous strain - B. bovis is host specific to cattle, but **cats are an incidental **host!!!
- In general, Bartonella spp. usually cause asymptomatic intra-erythrocyte bacteremia in the adapted
mammalian host
* Endocarditis might be described in some animal species such as cattle with B. bovis - CAT, DOG & RODENT HOSTS ARE THE MOST ZOONOTIC BARTONELLA SPECIES!!!
__
Pathogenesis & human specific Bartonella
Hemotropic –> has an affinity for ?
Nonhemolytic –>?
can it persist? how long? why?
- Hemotropic –> has an affinity for
erythrocytes, probably phagocytic cells - Bartonella spp. can be found at the site of
injured tissue due to the inflammatory
process - Nonhemolytic –> hides in erythrocytes and
does not cause blood cell destruction
and then further localizes in the
endothelium - Bacteria is preserved in the cell for efficient
vector transmission, protected from host
immune system, dispersed throughout the
body, challenging for antimicrobials to
reach the bacteria - Persist intracellularly for months to years by
intermittent bacteremia à cycle of
clearance and reoccurrence
Bartonella bacilliformis
Causative agent of ?
found where?
how many stages? what are they?
transmission?
- Causative agent of **Carrion’s disease **in humans seen mostly in Peru, Ecuador and Colombia
- Originally thought to cause 2 syndromes, but was later proved to be** 2
stages of disease caused by a single agent** - Oroya fever: acute disease, fever and hemolytic anemia
- Verruga Peruana (Peruvian wart): chronic disease causing bloody warts
- Transmission: sand flies
Bartonella Quintana
causative agent of what?
what result?
where is it found?
transmission?
cs?
what relevance dogs and cats?
Causative agent of trench fever which has a 5 day relapsing fever
-seen as a disease of homeless populations
transmission: human body lice
CS: recurring fever, lymphadenopathy, endocarditis
-bacillary andiomatosis in immunocompormised–>red proliferative nudules with vascularization
-sporadic description in dogs and cats
Cat specific Bartonella
who gets it?
reservoir?
CS in cats
what are they 3 most prominent
are they zoonotic?
- Commonly detected and cats are the natural reservoir:
* Bartonella henselae (most prevalent)
* Bartonella clarridgeiae (2nd most prevalent)
* Bartonella koehlerae (3rd most prevalent) - all zoonitic
*Dont cause cs in cats
Cat specific Bartonella
Bartonella clarridgeiae
causes what in what kind of cats?
associated with what in humans?
reservoir?
transmission?
causes bacteremia in healthy cats and is associated with a cat scratch “like” disease in humans.
reservoir: cats
transmission: c. felis-cat flea
Cat specific Bartonella
Bartonella koehlerae
is it common?
what is the source?
what relevance to humans and dogs?
cs in cats
reservoire?
-not frequently seen
-cats are the source that has been associated with human and canine endocarditis
-no cs in cats
reservoir: cat
Cat specific Bartonella
Bartonella henselae
reservoir?
does it cause bacteremia inhealthy cats?
is the bacteremia chronic or sporadic? is it recurrent?
zoonotic?
susceptible species?
transmission?
* Cats are the natural or primary reservoir of B.
henselae, and it will cause bacteremia in healthy
cats
* Bacteremia is chronic and recurrent, so it can persist for
months to years with relapse occurring every several
months
* Zoonotic bacteria causing Cat Scratch Disease in
humans
* Susceptible species: domestic and wild felines,
humans, and many other animals
* Transmission: C. felis (cat flea) vector via feces
* Intradermal inoculation of infected flea feces will result in
infection in cats
* Fleas have an important role in the transmission among
cats!!!
Cats & Bartonella
Bartonella quintana
should you treat cats?
detectible?
reservoir?
transmission?
Rarely detected in cats and causes Trench
Fever in humans
* Reservoir: humans
* Transmission: human body louse
*only treat cats if immunocompromised owner
Cats & Bartonella
Bartonella vinsonii subsp. berkhoffii
detectible?
zoonotic?
reservoir?
- **Detected in one cat **(suffered from osteomyelitis
and polyarthritis) - Zoonotic
- Reservoir: domestic and wild canids
Cats & Bartonella
Bartonella bovis
common?
reservoir?
what can it cause and to who?
Very rare, but was incidentally found in cats
* Not associated with clinical disease in cats
* Reservoir: cattle
* Causes endocarditis in cattle
Cats & Bartonella
Prevalence of Bartonella in cats?
CS in cats: ?
The 3 most common feline-associated species of Bartonella are ?
B. henselae is mainly transmitted form cats to humans via ?
- Prevalence of Bartonella in cats is very high in certain
geographical areas - CS in cats:
* Experimentally infected: cats typically have no clinical signs but can show some sporadic and non-specific signs (fever, lethargy, anorexia) - **Naturally infected: **rare to see CS, usually asymptomatic
- Endocarditis, myocarditis, uveitis, fever
- FeLV worsens the course of the disease
- The 3 most common feline-associated species of Bartonella are zoonotic!
- Immunocompetent: local, self-limiting signs
- Immunocompromised: systemic signs that can be fatal
- Occupational risk à veterinarians!
- B. henselae is mainly transmitted form cats to humans via cat
scratches - A cat has infected flea excrement under its claws and will
infect a human upon scratching them
Canines & Bartonella
reservoir?
prevalence in dogs?
presentation of clinical disease?
transmission?
CS in dogs?
- Canids are the natural reservoir for B. vinsonii subsp. berkhoffii and B. rochalimae
- B. henselae is more **prevalent in dogs **compared the species listed above, and can cause disease in dogs
- Long lasting bacteremia in healthy dogs, but **dogs present more clinical disease **compared to cats
- Transmission: Rhipicephalus sanguuineus and Ixodes spp. ticks
- B. henselae transmission is via C. felis, probably due to cat scratches
Canines & Bartonella
cs in dogs?
what relevance infectious endocarditis in dogs?
what result chronic cases?
why study dogs?
cs in humans?
dogs: various tissues inflammation, endocarditis, myocarditis, vasculitis, vascular proliferation (ex.
Hemangiosarcoma)
* **Infectious endocarditis **in dogs can be caused by several different Bartonella species!
* Chronic cases can result in immunosuppression
-
Dogs and humans have similar disease cause by Bartonella, therefore it seems that dogs may be the best
animal model to study Bartonella in humans -
CS in humans: vasculitis, endocarditis, myocarditis
*CS same in humans and dogs
Canines & Bartonella
Diagnosis, treatment and prevention
dx?
when should you test a healthy animal?
cytology?
serology?
PCR?
culture?
tx?
when to treat?
treat with what?
dogs?
prevention?
***** Dx: history and flea/tick exposure + clinical signs
* History of scratches in humans, healthy animals should be tested in the case of the owner being immunocompromised
* Cytology is NOT effective
* Serology for cats:
* Measures exposure in humans and animals, but caution cross reactivity with Rickettsia
* Can confirm infection in cats if IgG titers are compared
* PCR for cats and vectors:
* Confirm infection, **blood **is the best sample, more sensitive than culture
* Culture:
* Takes approximately 8 weeks and requires media enriched with BAPGM & chocolate or blood agar, in 5% CO2
* Bartonella alpha proteobacteria media
** Ideal recommendation: combo of PCR screening and culture to increase sensitivity (remember the bacteria hide in the erythrocytes)*
* Tx:
* Healthy cats should NOT be treated, only treat the cats showing clinical signs or if the owner is immunocompromised
* Doxycycline is the most recommended
* Dogs are more likely to show clinical signs
* Doxycycline, Enrofloxacin or Azithromycin
- Prevention: NO vaccine available, flea/tick control and routine testing of blood donors
