Emerging Infections

Question 1

For pandemic influenza to occur

Answer 1

• strain must be new to humans without a vaccine available
• cause significant disease in people
• prolonged person-to-person spread, which has not occurred for H10N8, H7N9, or H5N1.

Ex. H10N8 in China -> 2 out of 3, for epidemic potential, is good (for humans)!

Question 2

Pandemic 2014

Answer 2

February:
– Tick-Borne Borreliosis, Borrelia miyamotoi

– Polio-like illness, Enterovirus-68 causing Guillain-Barre’ syndrome

– Dengue virus, Type 5
– Norovirus, new strain
– Syphilis, increase in cases in US and CAN

March:

– Monkey Malaria to humans, Plasmodium knowlesi

Question 3

MERS-CoV

Answer 3

• Coronavirus, Enveloped, SS+ Polarity RNA
• Unique feature: helical nucleocapsid
• Zoonotic infection, 4 groups
  
  • Alpha: Bats
  • Beta: Bats
  • Gamma: Birds
  • Delta: Birds

Epi: Saudi Arabia

• 3 patterns of infection
  • Community acquired ( exposure source not known), but believed to include direct or indirect contact with animals- camels or bats
  • Hospital acquired infections
  • Infections acquired through close human to human contacts (household)

​​Pathogenesis

• Infects bronchial epithelium
• Evades immune attack
• Antagonistic to INF
• Attaches to CD26 (DPP4) peptide expressed in the bronchial epithelium and the kidneys
• Fatalities in patients with underlying chronic disease such as diabetes, heart disease, kidney disease etc.
• Mortality: 40%

Question 4

Chikungunya Virus

Answer 4

• Family: Togaviridae
• Enveloped, SS+ polarity RNA
• icosahedral nucleocapsid
• Transmission
  
  • Reservoir: Humans and Primates
  • Vectors: day biting mosquito Aedes aegypti & albopictus
• Incubation: 1 to 12 days (2-3 d common)

Etiopath:

• injection -> replicate in LN -> organ seeding
• counters type I(α and β) INF by viral NS2 protein
• Exact pathology is still unknown

Sx:

• fever (40C/ 104F),
• arthritis,
• Rashes (maculopapular or petechial)
• encephalitis
• no thrombocytopenia

NOTE: lymphopenia can be seen in first few days of viral illness

Dx: virus isolation, RT-PCR and serology

Prevention, No Vaccine is available, mosquito control

Question 5

Enterovirus D68

Answer 5

• Picornavirus; non-Polio Enterovirus, Naked, ssRNA
• 3 different strains have been isolated
• Diagnosis by real-time PCR