Term
| What are the 4 major Agents that are associated wtih Zoonoses? |
|
Definition
1) Hantavirus (ssRNA-negative, enveloped)
2) Rabies virus (ssRNA-negative, enveloped)
3) Rickettsiae (Atypical bacterial-obligate intracellular)
4) Borrelia burgdorferi (gram negative- lime's disease) |
|
|
Term
| What are 2 different patterns of Zoonitic Infection? |
|
Definition
All are relatively rare.
1) Dead-end host (Lyme, Rocky Mountain Spotted, Hantavirus, Rabies, anthrax)
2) Human-to-human transmission (Influenza, plague) |
|
|
Term
Hantavirus
1) Biology
2) Transmission
3) Virulence factors
4) Pathogenesis |
|
Definition
1) Spherical, enveloped ssRNA (-) virus with nucleocapsid containing 3 distinct RNAs (each has transcriptase that makes distinct RBP)
- Envelope buds from Golgi) and associated with 2 virally derived envelope glycoproteins.
2) Rodents are reservoir and infectious virus found in urine saliva and feces. Transmitted by BREATHING.
3) Glycoproteins determine host range and virus multiplies in infected host.
4) Enter respiratory tract and replicate, then spread via blood to other organs.
- Most asymptomatic with lasting immunity
- Can cause Hemorrhagic Fever (HF), HF with Renal Syndrome or Hanta virus Pulmonary Syndrome (HPS) |
|
|
Term
A patient presents with headache, myalgia, vomiting and diarrhea, and is showing signs of nephrotoxicity.
By RT-PCR, you identify viral RNA.
What type of infection are you observing? Treatment? |
|
Definition
This sounds like Hemorrhagic Fever with Renal Syndrome (HFRS) in Hantavirus
- IV transfusions of fluid and electrolytes, with kidney dialysis.
Remember, the majority of cases are asymptomatic and involve lifelong immunity. |
|
|
Term
A patient presents with headache, myalgia, vomiting and diarrhea, and is mildly neutrophilic with hemoconcentration and thrombocytopenia.
By RT-PCR, you identify viral RNA.
What type of infection are you observing? Treatment? |
|
Definition
Hantavirus Pulmonary Syndrome
-IV transfusions of fluid and electrolytes
Remember, the majority of Hantavirus infections are asymptomatic. |
|
|
Term
Rabies Virus
1) Biology
2) Transmission
3) Virulence factors
4) Pathogenesis |
|
Definition
1) Enveloped ssRNA (-) with helical capsid and trimers of single RNA, covalently attached to RdRp
- Large, "bullet shaped" virus.
2) Infect broad range of mammalian hosts (asymptomatic in many)
3) Neural tropism for AchR-
4) Animal bite spreads from peripheral muscle cells to CNS, to peripheral nerves and other organs (such as salivary glands).
- Death from cardiac and respiratory failure, encephalitis, autonomic dysfunction and vasospasm. |
|
|
Term
| Why are Zoonotic infections difficult to control? |
|
Definition
1) Host typically asymptomatic
2) Arachnid transmission |
|
|
Term
What are the major differences between Hantavirus and Rabies?
1) Virus
2) Reservoir
3) Transmission
4) Virulence
5) Diagnosis
6) Treatment |
|
Definition
1) Virus
-3 distinct RNAs (Hantavirus) vs. 3 identical RNAs (Rabies)
2) Reservoir
- Deer mouse (Hantavirus) vs. Diverse mammals (Rabies)
3) Transmission
- Aerosole (Hantavirus) vs. animal bite (Rabies)
4) Virulence factors
- 2 envelope proteins (Hantavirus) vs. Neuronal tropism (Rabies)
5) Diagnosis
- RT-PCR & exposures (Hantavirus) vs. Clinical history (Rabies)
6) Treatment
- IV fluids, electrolytes and dialysis (Hantavirus) vs. IgG and Inactivated vaccine (Rabies) |
|
|
Term
A patient presents with confusion, lethargy and increased salivation.
They are quite aggressive and refuse to drink water.
What is going on? How could you confirm? |
|
Definition
Sounds like Rabies.
- Hydrophobia is a tell-tale sign, as well as aggression and salivation
- Look for animal bites and collect a CLINICAL HISTORY.
- Secondarily, look for negri body in neuron and IF in expected animal |
|
|
Term
A patient presents with confusion, lethargy and increased salivation.
They are quite aggressive and refuse to drink water. You ask them about vaccinations and discover that they have not had a Rabies vaccine.
How might you treat? |
|
Definition
This is Rabies
1) Identify wound and cleanse with virucidal agent
2) Administer HRIG
3) With different syringe, vaccinate with HDVC (inactive) |
|
|
Term
A patient presents with confusion, lethargy and increased salivation.
They are quite aggressive and refuse to drink water. You ask them about vaccinations and discover that they have had the Rabies vaccine.
How might you treat? |
|
Definition
1) Cleanse wound with virucidal agent.
2) Give HDCV booster (inactive)
** DO NOT give HRIG** |
|
|
Term
| Why do patients infected with Rabies virus generally die? |
|
Definition
1) Cardiac and respiratory failure
2) Encephalitis
3) Autonomic dysfunction
4) Vasospasm. |
|
|
Term
| What type of pre-exposure treatment is available for Rabies virus? |
|
Definition
| Immunization with HDCV (inactive) in high risk populations |
|
|
Term
Rickettsia rickettsii
1) Biology
2) Transmission
3) Virulence factors
4) Pathogenesis |
|
Definition
1) Small, gram-negative, obligate intracellular pathogen.
2) Anthropod (Dermacentor) vectors cause RMSF in N. and S. America (untreated mortality of 25% and 4% with)
3) - Actin organization in host to form filopodia for spreading
- Phospholipases, Proteases and membrane peroxidation.
- steal ATP from host for ADP.
4)
- Mainly invade vascular endothelium
- Post-bite (2-12 days), disease begins abruptly with fever, malaise and frontal headache, with diarrhea, conjunctivitis and meningitis, ect.
- 2-4 days later, rash develops in extremities |
|
|
Term
| How are Rickettsia maintained in Dermacentor vectors? |
|
Definition
1) Trans-ovirially (transmission to offspring)
2) Trans-stadially (across life-cycle stages) |
|
|
Term
| What are the 3 features of Rickettsia virulence? |
|
Definition
1) Actin reorganization in host cell to make filopodia for spreading
2) Phospholipases, Proteases and membrane peroxidation.
3) Energy parasites (steal ATP for ADP) |
|
|
Term
| Which life-style stages of Dermacentor vectors of Rickettsia are infectious? |
|
Definition
|
|
Term
| What is the Weil-Felix test? |
|
Definition
| Test previously used to non-specifically diagnose Rickettsia by targeting Proteus vulgaris in leu of rickettsial antigens (not very sensitive or specific, but CHEAP) |
|
|
Term
A patient presents with severe frontal headache, rashes on their extremities and mental confusion.
You collect an exposure history and run an EIA for Rickettsia, which comes back positive.
How do you treat? |
|
Definition
Remember, CLINICAL SIGNS and exposure history are most important for Rickettsia.
If it is early, treat with Doxycycline. |
|
|
Term
| How can you visualize Borrelia burdorferi? |
|
Definition
| Like Treponema pallidum, you need Dark-field microscopy! |
|
|
Term
Borrelia burdorferi
1) Biology
2) Transmission
3) Virulence factors
4) Pathogenesis |
|
Definition
1) Spirochete with endoflagella that have "corkscrew" appearance"
2) #1 vector-borne disease in US (30,000 in 2010)
- Uses Ixodes tick vector (vs. Dermacentor in Rickettsia) that is infectious in nymph and adult stage.
3) Differentially expressed Osps (lipoproteins) in tick and human are important for adhesion (plasmid associated) and determine tropism
4)
Early (2-30 days) notice malaise, fatigue, chills and Bull's eye rash.
Early-Disseminated (2wk- 6 month)- 10% of patients experience cranial neuropathy and meningitis, as well as transient cardiac block
Late- Oligoarthritis in 60% of patients, ECM lesions and demyelination. |
|
|
Term
| What are the 3 phases of Lyme's disease? |
|
Definition
1) Early (2-30 days) notice malaise, fatigue, chills and Bull's eye rash.
2) Early-Disseminated (2wk- 6 month)- 10% of patients experience cranial neuropathy and meningitis, as well as transient cardiac block
Late (2month- 7 years)- Oligoarthritis in 60% of patients, ECM lesions (derm) and demyelination. |
|
|
Term
| How long does it take for a Ixode tick to transfer Rickettsia to a human once it has bitten? |
|
Definition
48 hours!
It attaches to proteoglycan receptor. |
|
|
Term
| You suspect Lyme's disease. How do you confirm? |
|
Definition
Two-tierd approach
1) Use EIA or IF (sensitivity)
2) Follow up with Western blot (specific).
** you can culture it easier than Rickettsia, but still not from a blood sample** |
|
|
Term
True or False:
There is a Lyme's disease vaccine. |
|
Definition
|
|
Term
| How do you treat early vs. late stages of Lyme's disease? |
|
Definition
Early- Erythema migrans (Doxycycline) and Meningitis or Carditis (IV Ceftriaxone)
Late- Arthritis (Doxycycline or Amoxicillin) and CNS (IV Xeftriaxone) |
|
|
Term
| Which Zoonotic pathogen is transmitted through rodent fecies in aerosole form? |
|
Definition
Hantavirus (usually asymptomatic with long-lasting immunity)
Uses 2 envelope glycoproteins to invade the respiratory tract causing HF, HFRS and/or HPS |
|
|
Term
| Which zoonotic virus causes mild neutrophilic leukocytosis, hemoconcentration and thrombocytopenia? |
|
Definition
| Hanta virus causing Pulmonary syndrome. |
|
|
Term
What is the mode of transport for each of the following Zoonotic pathogens?
1) Hantavirus
2) Rabes Virus
3) Rickettsia
4) Borrelia |
|
Definition
1) Aerosole from rodent feces
2) Animals bite from various mammals
3) Dermacentor tick
4) Ixodes tick |
|
|
