Zoonosis & Shared Infection Flashcards by Kayla Stauffer

what type of bacteria is bacillus

gram positive large rods

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are bacillus aerobic or anaerobic

aerobes or faculative anaerobes

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are bacillus slow or fast growing

very fast growing

large colonies at 24 hours

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what is anthrax caused by

bacillus anthracis

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what are susceptible to bacillus anthracis

ruminants – highly susceptible

pigs, horses moderately susceptible

carnivores comparatively resistant

birds almost totally resistant

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what is the epidemiology of anthrax

Endospore formation most important factor in persistence of anthrax in environment and spread to other animals

Endospores survive for decades in soil

Outbreaks occur in herbivores when pasture contaminated spores

Spores bought to surface by flood, excavation, subsidence, earthworm activity

Infection acquired by ingestion of spores (inhalation, skin abrasion more common in man)

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what are the virulence factors of anthrax

Presence of poly-D-glutamic acid capsule and complex toxin

Both violence factors encoded on plasmids

Expression regulated by host temp and carbon dioxide

Capsule inhibits phagocytosis

Toxin consists of 3 antigenic components (protective, edema and lethal factors)

PA acts as the binding moiety for both edema and lethal factor

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what is the edema factor of anthrax

calmodulin dependent adenylate cyclase increases cAMP causes build up fo fluid in tissues

also inhibits neutrophilic function

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what is the lethal toxin of anthrax and what does it do

Zinc metalloprotease plus PA which act as binding domain

Stimulates macrophages to release IL-1 beta and TNF alpha and cleave MAP kinase

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what does the lethal toxin of anthrax cause

Causes swelling, darkening of tissue, edema and necrosis

Septicemia leads to increased vascular permeability, hemorrhage, shock and death

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what is the incubation period of anthrax

hours to days

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what does anthrax cause in cattle and sheep

septic and rapidly fatal

most animals found dead

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what is characteristic feature of anthrax bacilli in the last hours of life

massive bacteremia

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how is anthrax diagnosed

Carcasses are bloated, putrefy and do not exhibit rigor mortis

Bleeding issues from mouth, nostrils, anus

Blood collected from animal stained with polychrome methylene blue

Blue bacteria pink capsules

Inoculate agar plates for growth

Characteristic colonial morphology, biochemical tests

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what is the apperance of b anthracis after staining

capsule and square ends

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what are the forms of anthrax in humans

cutaneous

pulmonary

intestinal

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what is the cutaneous form in humans of anthrax

Endospores enter abraded skin — septicemia if untreated

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what is the pulmonary form of anthrax in humans

Inhalation of spores

woolsorters disease

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what is the intestinal form of anthrax in humans

ingestion of infective material

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how is anthrax controlled

Do not open carcass as this will facilitate spore formation and environmental contamination

Report to regulatory authority

Annual vaccination

Stern live spore vaccine, capsule minus toxin +ve in endemic regions

Chemoprophylaxis

Carcass incinerated or buried away from water sources

Contaminated material disinfected in 10% formalin

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what is the plague caused by

Yersinia pestis

what type of bacteria is Yersinia pestis

gram negative bacterium

how is the plague infection spread

zoonotic infection in rodents transferred by fleas

organisms in blood of rodents, blood (+ organism) taken up by fleas and flea bites humans (or dogs or cats)

humans infected by flea bites

where is the plague endemic to

africa

asia

USA (southwest and pacific coast)

what species are susceptible to the plague

Varies of different wild rodent species Prairie dogs are extremely susceptible -- 99% mortality Kangaroo rats in North America

what does the clinical infection of the plague cause

Both dogs and cats in endemic areas Cats are particularly susceptible and may be a source * Usually acquired by ingesting rodents **Bubonic, septicemia, pneumonic**

what are cats with pneumonic plague a source of

human infection through aerosol generation human infection can be acquired through cat scratches and bites and fleas

what are the plague syndromes in humans

Bubonic: * Fever painful lymphadenopathy Septicemia: * Fever, hypotension with or without bubonic Pneumonic: * Cough, hemoptysis with or without bubonic Meningitis: * Fever, nuchal rigidity usually without bubonic

what are virulence factors specific to Yersinia pestis (5)

Fraction 1 (F1) antigen HPI Ymt protein on plasmid His locus Pla

what are the functions of Fraction 1 (F1) antigen

Capsule around bacteria which prevents opsonization

what are the functions of HPI

for iron acquisition (also Ye and Yp)

what are the functions of HPI of Y pestis

Ymt protein on plasmid is a phospholipase D required for survival in flea gut

what are functions of Hms locus of Y pestis

Hms locus required for efficient transmission to subcut sites

what is the function of Pla plasmid of Y pestis

Pla is plasmid encoded and essential to disseminate from subcut tissue to lymph nodes or bloodstream

how is Y pestis diagnosed

**Specimens sent to labs** * Pus, blood, lymph node aspirate **Giemsa stained smears of pus** * bipolar rods **Culture** **DFA tests (direct fluorescent antibody)** **Passive hemagglutination on paired samples from infected cats** * Rising titre suggests active infection

how is Y pestis treated

Cats with suspected plague isolated IV tetracycline or chloramphenicol for bubonic plague Endemic areas dogs, cats routinely treated for fleas

how is Y pestis controlled

Rodent control Effective human and animal surveillance Avoid sick/dead animals Avoid endemic areas or outbreak areas Vaccination Isolate human cases Treat human cases with antibiotics

what is the causative agent of Glanders

Burkholderia mallei

what is Burkholderia mallei

gram negative rod

where is Glanders infection

middle east india pakistan china mongolia

what is Glanders characterized by

Contagious disease of Equidae Nodules and ulcers in resp tract and skin

how is Glanders transmitted

Ingestion of food or water contaminated by nasal discharge of infected horses Inhalation or skin abrasions

what are the clinical features of Glanders in horses

**Acute septicemia** * with fever, mucopurulent nasal discharge and resp signs **Chronic disease more common** * Presenting as nasal, pulmonary and cutaneous forms **Ulcerative nodules** * Develop on mucosa of the nasal turbinates and nasal septum Animals may die after months or recover and shed organisms from RT or skin Pathogenesis not well defined — organism is dangerous to work with

how is Glanders diagnosed

Clinical signs Lab diagnosis by sending pus, lesion discharge, blood for serology Grows on sample media Serology Mallein test

how is Glanders treated and controlled

Test and slaughter Antibiotics inappropriate as treated animals may carry the organism and transmit it Cleaning and disinfecting

what is melioidosis caused by

Burkholderia pseudomallei

where is melioidosis endemic

Endemic in soil and water in south east Asia

how is melioidosis transmitted

Infection from ingestion, inhalation, skin abrasion from soil/water contact Opportunistic pathogen, stress-immunosuppression predisposes to clinical disease

what species are susceptible to melioidosis

Many animal species susceptible, including humans

what occurs following infection of melioidosis

Subclinical infection occurs in which the organism may remain latent and then re-activate Infection may be acute or chronic, septicemic, resp, disseminated and characterized by abscess formation

how is melioidosis diagnosed

Organism may be cultured on blood agar or Ashdowns medium