Exam 2: Zoonotic Diseases

Cat Scratch Fever, Plague, West Nile Virus, Ebola

Causitive agent for Cat Scratch Fever

*Bartonella henselae*

Characteristics of *Bartonella henselae*

* Bacterium
* Gram-negative
* Short rod

What is the average amount of cases of Cat Scratch Fever per year?

10,000

What depends on cats having Cat Scratch Fever?

Where they are located (rural or urban)

What are the human symptoms of Cat Scratch Fever?

* Swollen/painful lymph nodes
* Sore with pus and necrotic center at site of entry

What are the cat symptoms of Cat Scratch Fever?

* Most are asymptommatic
* Symptommatic= 1-2 day fever
* Fatigue
* Vomiting

How do cats contract Cat Scratch Fever?

Fleas

How do humans contact *Bartonella henselae*?

Cat Scratch

When is the most common time for people to contract Cat Scratch Fever?

Fall and winter

What are 3 methods used to diagnose *Bartonella henselae*?

* History
* PCR
* Culture

If Cat Scratch Fever is not self-limiting, what is the treatment?

Antibiotics

Are there any ways to prevent Cat Scratch Fever?

Not owning or playing with cats

What are some suspected methods of transmission for Cat Scratch Fever?

* Flea bites
* Ticks

What si the causitive agent of plague?

*Yersinia pestis*

What part of the “Plague Doctor’s Uniform” was filled with fragrant herbs?

Beak

What part of the “Plague Doctor’s Uniform” helped keep patients at a distance?

Stick

What part of the “Plague Doctor’s Uniform” helped with the sloughing off of liquids?

Heavy, waxy coat

What was the first pandemic of plague?

Justinian Plague

How long did the Justinian PLague last?

About 200 years

What was the second pandemic of plague?

Black Death

How long did the Black Death pandemic last?

400 years

What is the third plague pandemic we are currently in?

Modern Plague

Characteristics of *Y. pestis*

* Bacterium
* Very short rod
* Gram-negative

Where have the majority of current cases of plague originated from?

* Africa
* Madagascar

Where have most of the cases of plague originated from in the U.S.?

Western Coast

What 3 cases of plague in the Midwest and East Coast originated from the West Coast?

* Michigan
* Georgia
* Connecticut

Why wass the plague case in Illinois different?

Case originated from an attenuated strain of *Y. pestis*

How was the strain of *Y. pestis* attentuated?

Deficient in iron acquisition

Why was the researcher from Illinois able to die from the attenuated strain of the plague?

The researcher had hemochromatosis

What is the average numebr of cases of plague we can expect in the U.S.?

7 cases per year

What is the first category of the plague that occured from the 1900s-1920s in the U.S.?

Sporadic

From 1965 to now, what is the category that the plague falls into in the U.S.?

Endemic

What is the typical transmission of *Y. pestis*?

Bacterium typically cycles between rodents and fleas

What are two examples of larger-scale carnivores found to carry the plague?

* Domestic cats
* Mountain lions

What is the enzootic cycle?

When a disease is endemic in an animal population

How does the enzootic cycle related to plage?

* Lower rates of death
* Persists in animal populations
* Low rates of human infection

What is the epizootic cycle?

An animal epidemic

How does the epizootic cycle relate to plague?

* Massive spread
* High death rates
* Higher risk to human populations

What is the transmission for bubonic plague?

* Flea bites
* Contaminated fluids/tissues

What are the symptoms of bubonic plague?

* Fever
* Headaches
* Chills
* Weakness
* Buboes (extremely swollen lymph nodes)

What percentage of U.S. cases of plague are typically bubonic?

80%

What is the mortality rate of bubonic plague?

10%

What is the mildest form of plague?

Bubonic

How is the expression of *Y. pestis* different in fleas?

* Stops flea from digesting blood
* Flea panics and goes into feeding frenzy
* Flea will vomit up a *Y. pestis* biofilm that enters the human through a flea bite

What is the mortality rate of septicemic plague?

25-30%

What are the symptoms of septicemic plague?

* Fever
* Chills
* Weakness
* Pain
* Shock
* Bleeding
* Necrosis of fingers, toes, and nose
* Septic shock

What are the types of transmission for septicemic plague?

* Flea bites
* Contaminated tissues/fluids
* Untreated bubonic plague

What is the most dangerous type of plague?

Pneumonic

What are the symptoms of pneumonic plague?

* Fever
* Headache
* Weakness
* Pneumonia

What is the transmission of pneumonic plague?

* Inhaling infectious droplets
* Person-to-person
* Untreated bubonic or septicemic plague

What is the diagnosis of plague?

* Location (near an endemic area)
* Known flea bite or bubo
* Test blood or lymph node samples

What is the treatment of plague?

Antibiotics

What was the largest outbreak of plague in recent years?

Madagascar

How did the Madagascar plague epidemic spread so quickly?

Person-to-person droplet exposure

What was the first way Madagascar got the plague outbreak under control?

* Prophylactic antibiotics
* Contact-tracing

What was the second method Madagascar utilized to get the plague epidemic under control?

Started screening people

* Looking for fevers

Why were fleas one of the causes behind the Madagascar plague outbreak?

2 types of fleas

* One cycled during the dry season
* One cycled during the wet season

What types of resevoirs were prevalent in the Madagascar plague outbreak?

* Small mammals
* Shrews
* Rats

What was unique about some of the rats in the Madagascar plague outbreak?

Some of the rats were resistant to the plague

* They wouldn’t die
* The would carry and spread the plague

What were the ways that migration affected the spread of the Madagascar plague outbreak?

* People moved based on the season
* Moved from high plague areas to low plague areas

How did poverty affect the Madagascar plague outbreak?

* Poor nutrition
* Poor housing
* Overcrowding

What 3 categories of cultural practices aided in the spread of the plague in Madagascar?

* Medicine (traditional healers)
* Burial (exhumed the bodies of relatives)
* Crop storage (brought grains inside to prevent theft)

Where was the first case of West Nile in 1937?

Uganda

When were more severe cases of West Nile first recorded?

1990s

When was West Nile introduced to the U.S.?

1999

What were two theories on how West Nile was introduced to New York?

* Mosquitoes on a plane/boat
* Migratory birds

What was the New York outbreak first mistaken for?

St. Louis Encephalitis

What was the population that was mainly infected in the New York West Nile outbreak?

Elderly

What did all the elderly have in common in the New York outbreak?

Gardening at dusk

What was the vector for West Nile?

Culex Mosquitoes

Why was St. Louis Enccephalitis first mistaken for West Nile?

Tests were positive for St. Louis Encephalitis

How did officials determine St. Louis Encephalitis wasn’t the causitive agent in the New York outbreak?

Large numbers of dead birds were found across the city

* St. Louis encephalitis cannot affect birds

What family of viruses is West Nile in?

Flaviviridae

What is the type of RNA genome West Nile Virus has?

Positive-stranded

What are the other viruses that are in the Flaviviridae family?

* Dengue
* St. Louis Encephalitis
* Japanese Encephalitis
* Zika
* Yellow Fever

By what year was West Nile endemic in the United States?

2010

What was different about Texas in 2012?

* 1900 cases in one year
* Over 1/2 had neurological involvement
* Weather patterns changed
* Increased population of mosquitoes
* Virulent strain

What is the resevoir for West Nile?

Birds

What two factors help the Culex mosquito persist?

* Prefers to bite at dusk/ overnight
* Ability to survive in the cold weather

What are 3 possible ways that West Nile can be transmitted human to human?

* Blood transfusions
* Organ tranasplants
* Pregnancy

80% of West Nile patients are symptommatic or asymptommatic?

Asymptommatic

What are the symptoms for West Nile Fever?

* Joint pain
* GI symptoms
* Fever
* Aches
* Persists for 1 month or more

What are the 3 possibilities for neuroinvasive complications from West Nile?

* Meningitis
* Encephalitis
* Poliomyelitis

What are the two ways that one can be diagnosed with West Nile?

* Clinical signs
* Traveling to an outbreak area
* Antibody detection

What is the treatment for West Nile Fever?

Over the counter medications

What is the treatment for neuroinvasive West Nile symptoms?

Supportive care

Does protection against one strain of Ebola give protection against all strains?

No

Characteristics of Ebola virus?

* Pleiomorphic (can change shapes)
* Shepard’s crook

During the 1976 outbreaks of Ebola, what happened during the outbreak in the Democratic Republic of Congo?

* Missionary hospital took in patient with hemorrhagic fever symptoms
* Needles were sterilized properly (93% mortality rate)
* Not good infection control (55% mortality rate)

During the 1976 outbreaks of Ebola, what happened during the outbreak in Sudan?

* Started in cotton factory workers
* Factory was known to have bacts, rodents, and insects living in the factory
* 55% mortality rate

Characteristics of Ebola virus?

* Filoviridae family
* Enveloped virus with protruding spikes
* Pleiomorphic
* Single stranded RNA genomes

What are the two genera for Ebola virus?

* Ebolavirus
* Marburgvirus

What is the most severe strain of Ebola virus?

Zaire

What is different about Bundibugyo ebolavirus?

* Didn’t infect as many people
* One of the more severe forms
* 40% mortality rate

What is different about Ivory Coast ebolavirus?

* Only 1 person infected (researcher)
* Conducted a necropsy on Chimp and cut herself

What is different about Reston ebolavirus?

* Animal facility took in shipment of monkeys that showed signs of hemorrhagic fever
* 4 of the monkey workers had antibodies
* Not dangerous to humans; only nonhuman primates

What is different about Bombali ebolavirus?

* Only found in bats
* Least severe form of ebola

Mortality rate of hemorrhagic ebola virus?

25-90%

What 2 factors contribute to the pathogenesis of ebolavirus?

* Viral factors
* Overly strong immune system response

What is currently know about immunity in survivors?

* People retain antibodies for a long time
* Might develop lifelong immunity but not cross protection