4/24 zoonotic infections
Terms
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- Define zoonotic infections
- infections of nonhuman hosts that are transmitted to humans. e.g. bioterrorism agents; emerging infections
- Zoonotic infections are spread by 4 methods. They are:
- Bites; Inhalation; Ingestion; Fecal/oral
- Etiology of Lyme Disease is ?? Name another organism with the same shape
-
Borrelia burgdorferi
(G-, spirochete). Treponema Pallidum (Syphillis) is also spiral shaped. -
Lyme disease reservoir
AND
Lyme disease vector -
Res: mice
AND
Vec: ticks (infection through bite) - 4 stages in natural history (progression) of Lyme disease
- Localized early disease -> Early disseminated -> Disseminated -> Chronic
- Localized early Lyme disease shows erythema migrans - describe it.
- Erythema migrans - annular, sharply demarcated, non-tender, may have bull's-eye appearance.
-
Early dissemintaed Lyme disease includes:
Is treated with -
secondary lesions on skin
fever and malaise, arthralgia & myalgia
Acute Arthritis appears.
Treated with:
Antibiotics doxy and amoxi - Disseminated Lyme Disease includes
-
Carditis, neurologic manifestations.
Arthritis - Chronic Lyme Disease shows:
-
Neorologic symptoms
Chronic Arthritis - defined as >1 yr of arthritis. Does not respond to antibiotics - Diagnosis for Lyme disease requires:
-
Differential - Erythema Migrans
Serology - ELISA + Western blot.
PCR can be used in difficult patients as culture is not easy to create. - Define arboviruses. What are the reserviors?? What are the hosts??
-
viruses transmitted by arthropods e.g. ticks, mosquitos.
Reservoirs: birds
Host: horses and humans are dead-end hosts - Arboviruses found in US
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Eastern and Western Equine Encephalitis viruses;
West Nile;
St. Louis Encephalitis virus;
LaCrosse virus;
Colorado Tick Fever - The US is at risk for Dengue fever virus and ??
- Yellow fever.
- A virus similiar to St Louis Encephalitis Virus was found in dead birds. It was found to be ??
- West Nile Virus. First entered US in 1999.
- WNV has birds as reservoir, and what as vector ??
- Mosquitos
- Dengue Fever is also called Break-bone fever. It has 4 serotypes. Reinfection with different serotype results in ??
- severe immune mediated hemorrhagic disease and shock
- Dengue vector and reservoir ??
-
Vector: mosquitos
Reservoir: humans
Same for Yellow fever, too. - Characterized by high fever, chills and then liver damage. Cases occurred while building Panama canal - name the zoonotic infection.
- Yellow fever.
- Controlling mosquito borne viruses includes what measures ??
-
1. Surveiallnce of horses, mosquitos, birds
2. Environmental clean-up.
3. insecticides
4. avoid mosquito bites -
Wwat zoonotic infection matches the description:
bi-phasic episodes of fever, chills, arthrlagia, headalgia; prolonged recovery time; disease localized to W US 4000ft and higher - Colorado Tick fever, which is not a neurologic disease by the way.
- Colorado Tick Fever charactistics:
-
Vector: tick D. andersoni
Res: rodents
virus replicates in bone marrow stem cells. - Rabies - list major reservoirs.
- Raccoons, skunks, bats.
- Stages in Rabies virus infection:
- animal bite -> prolonged replication at site -> ascend sensory nerve -> replicate in ganglia -> ascend to brain -> replication/transmission in saliva.
- Describe two forms of rabies infection
-
FURIOUS:
aggression, confusion, salivation, hydrophobia
DUMB:
weak, inability to swallow, salivation, choking. - Rabies post-exposure prophylaxis
- give Immunoglobins and active vaccine. Human rabies Ig milked from vet students - no joke.
- Regarding rabies, Why can one wait for a few days after animal bite before receiving treatment?
- rabies virus replicates at bite site slowly. Wait and observe wound and animal when vaccination status of animal unkown (unless the animal is a skunk, bat or raccoon)
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Pasteurella sp; S.aureus; and Alpha + Beta Strep sp are associated with ??
AND
Bacteroides, Actinomyces, Fusobacterium -
Dog Bites.
AND
Anaerobes associated with dog bites. -
Pasteurella canis and multocida.
Found where?? Cause what?? Treated how?? -
G- coccobacilli. Normal dog/cat flora.
Localized cellulitis/lymphadenitis, abcess, tenosynovitis, osteomyelitis, septic arthritis (latter two with cats)
Susceptible to several antibiotics. - Management of dog/cat bites
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culture wound; irrigation; debridement; antibiotics should cover Pasteurella, Strep, Staph, anaerobes.
Amoxicillin w/clavulanate often used. -
Regional, unilateral lymphadenitis. Usually benign and self limited illness. Sometimes whole arm could swell up. Common in children.
Name it ??? - Cat Scratch Fever courtesy of Bartonella henselae.