SAM Zoonotic Diseases

From Greek: Zoon = _______

animal

From Greek: Noses = _______

disease

Zoon_ _ _ _ = singular

zoonosis

Zoon_ _ _ _ = plural

zoonoses

What is a zoonotic disease?

Diseases and infections which are naturally transmitted from animals to humans.

What is reverse zoonosis?

when human gives to animal

What is Xenozoonosis?

not direct transmission route, blood transfusion, etc

What is Epidemiology?

the branch of medicine that deals with the incidence, distribution, and possible control of diseases and other factors relating to health.

about __% of pathogens are zoonotic

60%

about __% of emerging diseases are zoonotic

75%

How many zoonotic diseases exist?

more than 250

Transmission ____________.

varies

Risk is ______ from lab animals

low

People at risk for zoonotic diseases? (x7)

1. Newborns/children
2. Immuno-compromised: diabetics, AIDS
3. Elderly
4. Slaughterhouse workers: touching animal and animal biproducts
5. Farmers/staff
6. Veterinarians/staff
7. Pet owners

Factors that promote zoonoses? (x5)

1. Frequent contact with domestic animals
2. Overlap with wildlife habitat: hunt/hike
3. Poor animal sanitation
4. Poor personal hygiene
5. Intensive livestock production

What is a host?

An organism that is infected with or is fed upon by a parasitic or pathogenic organism. The host does not benefit and is often harmed by the association.

What is a reservoir?

Any person, animal, plant, soil or substance in which an infectious agent normally lives and multiplies. The reservoir typically harbors the infectious agent without injury to itself and serves as a source from which other individuals can be infected.

The ___________ _____________ primarily depends on the reservoir for its survival.

infectious agent

It is from the ___________ that the infectious substance is transmitted to a human or another susceptible host

reservoir

What is a vector?

an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another.

Examples of a vector? (x7)

mosquitos, mice, raccoons, birds, bats, fleas, ticks

What is an agent? examples?

causative agent. often bacteria/virus/parasite/fungus

What is transmission?

initial transport of a pathogen to the host; must be transmitted from one host to another.

Direct vs. Indirect transmission?

#NAME?

What is a diagnosis?

the identification of the nature of an illness or other problem by examination of the symptoms and/or signs and/or diagnostic testing

What is a differential diagnosis?

other diseases or illnesses that it could be

What is a prognosis?

the likely course of the disease

What is a sign?

Any objective evidence of disease, as opposed to a symptom, which is, by nature, subjective.

What is a symptom?

Any subjective evidence of disease.

Animals can show ________.

signs

Humans can show _________.

signs and symptoms

What is Morbidity?

incidence of the disease or the rate of sickness (how often and how quickly)

What is Mortality?

number of deaths in a given time (death rate)

Tx stands for?

treatment

Hx stands for?

History

Px stands for?

prognosis

Dx stands for?

Diagnosis

Abx stands for?

antibiotics

DDx stands for?

Differential Diagnosis

What are the four Etiological Classifications?

� Viral
� Bacterial
� Parasitic
� Mycotic (fungal)

Viral Zoonoses? (x3)

� Contagious Ecthyma
� Lymphocytic Choriomeningitis
� Acute Viral Encephalitis (Rabies)

Bacterial Zoonoses?

� Avian Chlamydiosis
� Salmonellosis

Parasitic Zoonoses? (x1)

Toxoplasmosis

Mycotic Zoonoses? (x1)

Dermatophytosis

Contagious Ecthyma: common name?

Orf

Contagious Ecthyma: Agent?
� is _______. will _______ on hair and skin of animal.

DNA virus (Parapoxvirus). Is hardy; persist on hair and skin of animals

Contagious Ecthyma: Reservoirs?

Domestic and wild ungulates (hoof stock)

What is the technical term for hoof stock?

ungulates

Contagious Ecthyma: Occurence?
� common or uncommon?
� worldwide?

Incidence uncommon BUT is worldwide, especially where sheep and goats are raised.

Contagious Ecthyma (Human cases) are most common in ________________.

New Zealand

Contagious Ecthyma is an __________________ disease.

occupational

Contagious Ecthyma: Transmission?
� direct vs indirect?
� Ewes that nurse infected lambs: _______________________

� Direct contact: touching directly. lesions and/or MM infected animals
� Indirect contact: knives, shears
� Ewes that nurse infected lambs: teat and udder infections

Contagious Ecthyma in Animals: Signs? (x2)

� Pustules on skin, eyelids, ears, lips, and nostrils
� Lesions - painful and can interfere with feeding

Contagious Ecthyma in Animals: Treatment? (x2)

� Supportive therapy
� Antibiotics (Abx) only if secondary bacterial infection

Contagious Ecthyma in Animals: Diagnosis?

Usually by clinical signs. Not concrete diagnosis

Contagious Ecthyma in Animals: Prognosis?
� Morbidity ?
� Mortality?
� can lead to a _____ ______ _____ because of ________.

� Morbidity (incidence) is high
� Mortality (death) is low
� Secondary bacterial infection or maggots

Contagious Ecthyma in Humans: Signs and Symptoms? (x2)

� Large pustular region at site of virus entry, Usually on hands, arms, or face. Very painful; eventually oozes
� Secondary bacterial infection

Contagious Ecthyma in Humans: diagnosis? (x2)

� Physical exam
� patient History

Contagious Ecthyma in Humans: Treatment? (x2)

� no specific treatment. Supportive therapy
� Abx to treat bacterial infections

Contagious Ecthyma in Humans: Prognosis?
� will resolve in ______ to _______ ________.
� can spread to ________.

� Most cases resolve in 2-4 weeks
� Can spread to eyes

Contagious Ecthyma: prevention? (x2)

� Good personal hygiene
� Good animal husbandry practices

Contagious Ecthyma: vaccine?

� Crude live vaccine for lambs (can get it from vaccine). In general don't do it, but new Zealand, etc. might

Contagious Ecthyma: reporting?

not required

Etiological Classification of Contagious Ecthyma

viral

Lymphocytic Choriomeningitis: abbreviation?

LCM

Lymphocytic Choriomeningitis: agent?

Lymphocytic Choriomeningitis Virus (LCMV)

Lymphocytic Choriomeningitis: reservoir?

� Wild house mice
� Domestics: mice go into cage and spread it

Lymphocytic Choriomeningitis: occurence?
� worldwide?
� ____________ _______________ making hard to determine incidence rates or prevalence by geographical regions

� Europe, Americas, Australia, Japan
� Under-reported making hard to determine incidence rates or prevalence by geographical regions

Lymphocytic Choriomeningitis: transmission?
� found in?
� Humans & pet rodents?

� Virus found in saliva, urine, and feces of infected wild mice. Shed virus for duration of life while remaining sub-clinical
� Other rodents, especially hamsters, not natural reservoir BUT can become infected
� Humans contract more from wild mice than pe

Lymphocytic Choriomeningitis most common transmission route?

in utero

Lymphocytic Choriomeningitis in animals: signs? (x4)

� Naturally infected mice show no clinical signs
� Mice infected in utero, Often runted
� Adults: acute immune-mediated diseases
� Hamsters: Weight loss, tremors, seizures

Lymphocytic Choriomeningitis in animals: Diagnosis? (x2)

� Serology/bloodwork
� PCR (polymerase chain reaction)

Lymphocytic Choriomeningitis in animals: Treatment & prognosis

� Supportive therapy in the case of a pet rodent
� High mortality

Lymphocytic Choriomeningitis in humans is a _____________ illness

Bi-phasic febrile illness

Lymphocytic Choriomeningitis in humans: signs and symptoms STAGE 1
� lasts how long?
� common symptoms?
� uncommon symptoms?

Initial phase
� Last up to a week
� Fever, malaise, lack of appetite, muscle aches, headache, nausea, vomiting
� Less frequently - sore throat, cough, joint pain, testicular pain, salivary gland pain

Lymphocytic Choriomeningitis in humans: signs and symptoms STAGE 2

Secondary phase
� Following a few days of recovery - symptoms of meningitis; characteristics of encephalitis
� Hydrocephalus
� Myelitis
� Myocarditis

What is Encephalitis?

inflammation of brain

What is Hydrocephalus?

water on brain

What is Myelitis?

spinal cord inflammation

What is Myocarditis?

heart muscle inflammation

Lymphocytic Choriomeningitis in humans: onset?

Onset 8-13 days after exposure

Lymphocytic Choriomeningitis in humans: Diagnosis STAGE 1 (x3)

� leukopenia (decreased WBCs)
� thrombocytopenia (decreased platelets)
� liver enzymes elevated

What is leukopenia?

decreased WBCs

What is thrombocytopenia?

decreased platelets

Lymphocytic Choriomeningitis in humans: Diagnosis STAGE 2 (x2)

� leukocytosis (increased WBCs)
� decrease in glucose levels in cerebrospinal fluid (spinal tap)

What is leukocytosis?

increased WBC

Lymphocytic Choriomeningitis in humans: Treatment (x3) & Prognosis

� Hospitalization and supportive therapy based on severity
� Anti-inflammatory drugs- steroids
� Anti-viral drugs
� Mortality less than 1%

Etiological Classification of Lymphocytic Choriomeningitis?

viral

Lymphocytic Choriomeningitis in humans: Prevention (x2)

� Avoid contact with wild mice
� Take precautions handling pet rodents

Acute Viral Encephalitis: common name?

Rabies

Acute Viral Encephalitis: Agent?

� RNA virus
� Lyssavirus

Acute Viral Encephalitis: Reservoir? (x6)

Dogs, fox, coyotes, skunks, raccoons, bats, etc.

Acute Viral Encephalitis: Occurence/Mortality
� Worldwide?
� ____-____deaths/year mostly in _____________ _______________.

� Worldwide in humans
� 40-70K deaths/year mostly in developing countries

Acute Viral Encephalitis: Transmission?
� what are the two cycles?
� Virus is abundant in __________.
� Most cases caused by _____________________. can be ______ or ______.
� Virus can be _____________. Example: ___________

� Two Cycles: urban and sylvatic
� Virus is abundant in saliva
� Most cases caused by bite from infected animals BUT indirect or direct
� Virus can be aerosolized - ex: bat caves

Acute Viral Encephalitis: Transmission? Urban

transmitted by dogs; accounts for most human cases

Acute Viral Encephalitis: Transmission? Sylvatic

circulates among wild carnivores and bats; causes spillover infections of dogs, cats, livestock

Acute Viral Encephalitis in Animals: two types

Furious & Paralytic

Acute Viral Encephalitis in Animals: Furious
� Signs?
� occurs in?

� dogs, cats, wild mammals
1) Agitated, restless, excitable in early stage
2) Aggressive phase follows. bites others and self
3) Profuse salivation (paralysis of throat muscles); bark turns to a hoarse growl
4) Convulsions and paralysis occur before death

Acute Viral Encephalitis in Animals: Paralytic
� Signs?
� occurs in?

� cattle
1) Initially muscles of head and neck affected
2) Difficulty swallowing
3) Paralysis spreads to extremities - generalizes - death follows

Acute Viral Encephalitis in Animals: Diagnosis

� Behavioral changes; history
� Immunofluorescence on brain tissue- after euthanasia

Acute Viral Encephalitis in Animals: Treatment

Euthansia

Acute Viral Encephalitis in Humans: Incubation

Incubation period variable - onset 3-8 weeks after exposure up to years later

Acute Viral Encephalitis in Humans: Signs and Symptoms

� Discomfort and irritation in area of bites
� Sensory changes, apprehension, headaches, low grade fever; lethargy
� Salivation increases
� Paralysis - not wanting to drink or swallow water. Convulsions and other mental disturbances are terminal events

Acute Viral Encephalitis in Humans: Prognosis

� Death from resp failure 2-8 days after onset

Acute Viral Encephalitis in Humans: Diagnosis

� Presumptive Dx - immunofluorescence of skins sections from back and neck, not always accurate
� Post-mortem exam and testing of brain tissue

Acute Viral Encephalitis in Humans: Treatment

� Almost always fatal!
� Once clinical disease has developed there is not effective Tx options
� Supportive therapy

Acute Viral Encephalitis: Prevention for Animals

� Pre-exposure vaccine
� Rabies laws are state and county contingent

Acute Viral Encephalitis: Prevention for Humans

� Pre-exposure vaccine
� Post-exposure vaccine

Acute Viral Encephalitis: report?

must report!

Etiological Classification of Acute Viral Encephalitis?

Viral

Etiological Classification of Toxoplasmosis?

parasitic

Scientific Name of Toxoplasmosis Agent?

Toxoplasmosis gondii

Toxoplasmosis: Agent?

Toxoplasmosis gondii: obligate intra-cellular sporozoan parasite

Toxoplasmosis: Reservoir?
intermediate hosts?

� Domestic cats only known definitive host
� Sheep, goats, swine, cattle, and chickens - intermediate hosts that carry infective stage encysted in muscle tissue

Toxoplasmosis: Occurrence?

� Worldwide
� Livestock - depends on # cats in pasture (too many is bad idea)

� Up to ______% human adults seropositive (exposed to it)
� _____% of domestic cats in some countries are seropositive

� Up to 70% human adults seropositive (exposed to it)
� 60% of domestic cats in some countries are seropositive

Toxoplasmosis: Transmission in Animals?

� Other animals become infected when consume infected soil or contaminated material

Toxoplasmosis: Transmission in Humans?

� Primary infection/transmission - eating raw/undercooked meats (esp pork or mutton); fecal-oral route
� Congential infection/transmission - transplacental; primary infection during pregnancy; parasite infects fetus; highest risk of contraction 1st and 2n

Toxoplasmosis in Animals: signs?

� Subclinical w/little morbidity or mortality in most
� Sheep - abortion; congenital dz that results in fetal mortality
� Cats - subclinical BUT kittens - diarrhea, hepatitis, pneumonia

Toxoplasmosis in Animals: diagnosis? (x2)

� Fecal floats
� Serological tests for some species (cats)

Toxoplasmosis in Animals: treatment? Prognosis?

� None if subclinical
� Supportive therapy for kittens
� Abx (especially sulfur drugs) to inhibit repro
� After primary infection - cat sheds oocysts in feces for 1-2 weeks
� Oocysts become infective 1-5 days after being passed; can survive in soil for ab

Toxoplasmosis in Humans: Signs and symptoms

� Immunocompetent adults - asymptomatic; sometimes mono-nucleosis type illness
� Oocysts can stay in muscle tissue- reactivate if become compromised

Cerebral toxoplasmosis - AIDS patients; _____ die

� Cerebral toxoplasmosis - AIDS patients; 10% die

Congenital Toxoplasmosis
� what is it?
� 1st trimester: _____ fetuses become infected; _____ severe
� 2nd trimester: ____ fetuses become infected; ____ severe. what happens?
� 3rd trimester: what happens

� 1st trimester - 17% fetuses become infected; 80% severe
� 2nd trimester - 25% fetuses become infected; 30% severe; abortion or premature birth
� 3rd trimester - fewer cases; CNS and eye infections/deformities; encephalitis; hydrocephalus; blindness; men

Toxoplasmosis in Humans: Diagnosis

� Clinical signs/history of exposure
� Serology tests

Toxoplasmosis in Humans: Treatment

� None for healthy people
� Pregnant woman with primary infections - special drug to prevent fetal infection
�Infants/immunocompromised - folic acid plus anti-toxoplasmal drugs

Toxoplasmosis Prevention

� Wash hands after cleaning litter boxes, gardening wear gloves
� Pregnant woman and immunocompromised - serology done to see if they have a titer against Toxo - if not, avoid handling cat feces, eating undercooked or raw meat

Toxoplasmosis: Reportable? Vaccine?

no. no

Etiological Classification of Avian Chlamydiosis?

Bacterial

Scientific name of Avian Chlamydiosis?

Ornithosis/Psittacosis

Avian Chlamydiosis: agent?

� Chlamydophila psittaci
� Obligate, intra-cellular gram negative bacteria
� Unique biphasic repro cycle - only one phase is infectious

Avian Chlamydiosis: agent scientific name?

Chlamydophila psittaci

Avian Chlamydiosis: reservoir?

Birds - especially psittacines (parrot); doves, pigeons, poultry

Avian Chlamydiosis: occurence?
� ___% wild psittacines
� ____-___% - feral pigeon pop. may be carriers

� Worldwide
� 1% wild psittacines
� 50-90% - feral pigeon pop. may be carriers
� Exotic bird owners/breeders, zoo staff, avian quarantine station workers

Avian Chlamydiosis: Transmission?

� Dried feces/nasal secretions and feather dust - aerosolized
� Cleaning cages
� Sneezing and wing flapping

Avian Chlamydiosis in Animals: Signs

� Peracute, acute, chronic strains
� Subclinical carriers
� Depression, anorexia, yellow/green diarrhea, conjunctivitis: eyes infected looking, nasal discharge, respiratory issues

Avian Chlamydiosis in Animals: Diagnosis

� Difficult depending on strain and stage
� Dead birds - impression smears of organs
� Live birds - ELISA; cultures (fecal and oral); may be negative if early stage of dz

Avian Chlamydiosis in Animals: Treatment & Prognosis

� Morbidity and mortality depend on strain
� Abx - clinical cases; sometimes longer than 45 days
� Supportive therapy

Avian Chlamydiosis in Humans: Signs and Symptoms

� Incubation 1-4 weeks
� Onset sudden or gradual
� Fever, chills, headache, muscle aches, URI, LRI
� Elderly - more severe. Such as encephalitis, hepatitis, arthritis, thrombophlebitis (vessels in legs swell. VERY painful)

Avian Chlamydiosis in Humans: Treatment and Prognosis
� Most cases _______, recovery in__________ w/ Tx
� Fatality rate ____________

� Most cases mild, recovery in 7-10 days w/ Tx
� Fatality rate less than 1%
� Abx
� Supportive therapy

Avian Chlamydiosis in Humans: Diagnosis

� Hx (history): do they have birds?
� Serology
� Cultures - blood or sputum (saliva)

Avian Chlamydiosis: Prevention

� 30 day quarantine - only rules out New Castle Dz
� 30 day Won't rule out Ornithosis - Infected birds can look healthy but shed dz
� Masks, gloves, protective clothing
� Cage papers - wet with ammonia, away from birds first.

Avian Chlamydiosis: vaccine, report?

� No vaccine for birds or humans
� MUST report to local health authorities

Etiological Classification of Salmonellosis

bacterial

Salmonellosis: Disease vs. Bacteria?

Disease (salmonellosis) vs bacteria (salmonella)

Salmonellosis: Agent

� Rod shaped, gram negative bacteria
� Many different strains named according to area first isolated

Salmonellosis: Agent scientific name

Salmonella enteritidis

Salmonellosis: Reservoir

� Warm AND cold blooded animals
� Domestic AND wild
� Reptiles - turtles, snakes, iguanas - subclinical carriers
� Chicks

Salmonellosis: Occurence

� Common in humans and animals; worldwide
� Human - food-borne or water-borne
� Major cause of GI illness/diarrhea
� Highest incidence- infants, young children, immunocompromised, elderly
� Occupational exposure

Salmonellosis: Transmission

� Consumption of contaminated foods (poultry, eggs, milk)
� Fecal-oral route
� Indirect contact - touching contaminated food/water bowls
� Bacteria can remain viable for months in dried feces

Salmonellosis in Animals: signs

� Clinical - weakness, fever, recumbency, diarrhea
� Young animals more often. Ex: calves
� Chronic carrier states (reptiles) - fecal carriage rates exceed 90%

Salmonellosis in Animals: diagnosis

� Clinical - isolate organism from blood or internal organs at necropsy
� Chronic carrier - cultures from rectum, cloaca, feces

Salmonellosis in Animals: treatment

� Clinical only - Abx; supportive therapy

Salmonellosis in Humans: signs/symptoms & prognosis

� Acute enterocolitis within 12-36 hours after ingestion
� Headache, abdominal pain, diarrhea, nausea, sometimes fever
� Most cases resolves untreated in a few days
� Rarely fatal except children, elderly, immunocompromised
� Meningitis and/or septicemia

Salmonellosis in Humans: Diagnosis

� Fecal cultures
� Blood if septic

Salmonellosis in Humans: Treatment
� Rarely give _____ . they ______________
� ____ if severe
� ____________________ - hydration!
� however, no ________________ because __________________________________________.

� Rarely Abx - prolong shedding
� Abx if severe
� Supportive therapy - hydration!; however no anti-diarrheals because you want disease to pass as quickly as possible.

Salmonellosis: Prevention

� HANDWASHING!!!!!!!!!!!!!
� Gloves!!!!!!!!!
� Young children, pregnant woman should NOT handle reptiles or young chicks

Salmonellosis: Report?

must report to local health authorities

Dermatophytosis: Etiological Classification?

Mycotic

Dermatophytosis: Common name

Tinea/Ringworm

Dermatophytosis: Agents?

Microsporum canis, Trichophyton mentagrophytes, Trichophyton verrucosum

Dermatophytosis Agents: Trichophyton mentagrophytes. Is what?

Ringworm of beard

Dermatophytosis Agents: Microsporum canis

Humans and animals; usually scalps or bodies of people

Dermatophytosis Agents: Trichophyton verrucosum

Face and upper body

Dermatophytosis: Reservoir for Canis?

Canis - carried by dogs and cats

Dermatophytosis Reservoir for Mentagrophytes:

Mentagrophytes - wild mice and rats; dogs; cats; horses; sheep; rabbits; guinea pigs

Dermatophytosis Reservoir for Verrucosum?

Verrucosum - cattle; sheep; other ruminants

Dermatophytosis: Occurence?

� Worldwide (human and animal)
� occupational

Dermatophytosis: Transmission

� Direct or indirect contact

Dermatophytosis in Animals: Signs

� Canis - 90% of cats no visible lesions - BUT if they do - on face and paws; dogs anywhere on body
� Cattle - small grayish/white scaly patches with hairloss on face/head (thickens/scaby)

Dermatophytosis in Animals: Diagnosis

� UV light on hairs: will be fluorescent
� Culture hairs

Dermatophytosis in Animals: treatment

� Betadine
� Topical
� Oral

Dermatophytosis in Humans: signs and symptoms

� Scaly patches, baldness, brittle hair
� Raised red circular lesion

Dermatophytosis in Humans: diagnosis

� Same as in animals

Dermatophytosis in Humans: treatment

� Same as in animals

Dermatophytosis: Prevention

� Avoid contact
� Hygiene!

Dermatophytosis: Vaccine? reportable?

� yes, for cats and cattle
� not reportable.

The Five Stages of Zoonotic Diseases: Stage 1

The pathogen is present in animals, but does not effect humans under normal conditions.

Stage 1 Example?

Feline distemper

The Five Stages of Zoonotic Diseases: Stage 2

The pathogen can be transmitted from animals to humans, but it cannot spread from human to human.

Stage 2 Example?

Nipah Virus

The Five Stages of Zoonotic Diseases: Stage 3

The pathogen can be transmitted from animals to humans and can pass between humans. However, the pathogen is not well adapted to humans and the pathogen will die out after a few cycles of transmission.

Stage 3 Example?

Ebola Virus

The Five Stages of Zoonotic Diseases: Stage 4

The pathogen can be transmitted from animals to humans and can pass between humans. It can adapt to living in humans for long periods of time without going back to animal hosts.

Stage 4 Example?

Cholera

The Five Stages of Zoonotic Diseases: Stage 5

A pathogen that exclusively infects humans. The pathogen may have co-evolved with humans or colonized humans recently and evolved into a specialized human pathogen.

Stage 5 Example?

HIV