Viral Zoonoses

Question 1

Define Zoonosis

Answer 1

• a disease that is not maintained primarily in the human population, but is transmitted to humans from a primary reservoir in another vertebrate host

Question 2

Define Epizootic

Answer 2

A disease which has spread throughout an animal population
(avian flu, foot & mouth disease)

Question 3

What are some different forms of viral zoonoses ?

Answer 3

• host-to-host (rabies, Lassa fever, Ebola)
• Arthropod-borne (arboviruses) - collective name for viruses transmitted by mosquitoes/ticks

Question 4

Describe Zika virus

Answer 4

• family = Flaviviridae, gene= Flavivirus
• transmitted by Aedes mosquitoes
• circulates in africa, americas, asia & pacific
• sexual transmitted has been documented
• link between Zika & microcephaly and other neonatal malformations

Question 5

What are symptoms of Zika virus ?

Answer 5

• acute, self-limiting
• 2-7 days of mild fever, rash, muscle & joint pain, malaise or headache
• link to Guillain-Barré syndrome

Question 6

How is Zika controlled ?

Answer 6

• no treatment or vaccine
• vector control, scrupulous avoidance of mosquito bites
• avoidance of travel to endemic areas
• diagnosis by PCR only

Question 7

Describe the Ebola virus

Answer 7

• family= Filoviridae, genus=Ebolavirus
• 6 species –> Bombali, Bundibugyo, Reston, Sudan, Tai Forest, Zaire

Question 8

What are the symptoms of ebola ?

Answer 8

• fever, fatigue, muscle pain, headache & sore throat
• vomiting, diarrhoea, rash, renal and liver dysfunction
• internal & external bleeding

Question 8

How is ebola transmitted?

Answer 8

• natural hosts are Pteropodidae fruit bats
• transmitted by direct contact with infected fluids or tissues

Question 9

How is ebola treated ?

Answer 9

• no vaccine
• control based on risk reduction & outbreak containment

Question 10

How is the risk of ebola reduced ?

Answer 10

• Wildlife-to-human = animals should be handled with PPE & meat should be cooked thoroughly
  -Human-to-human =PPE should be worn when treating ill patients

Question 11

What are some outbreak containment measures?

Answer 11

rapid diagnosis & understanding transmission ;
- prompt & safe burial of dead
- identifying & monitoring contacts
- barrier nursing
- isolation/cohorting of sick
- good hygiene & maintaining a clean environment

Question 12

How is ebola diagnosed ?

Answer 12

• clinical diagnosis
• RT- PCR assay
• ELISA test
• electron microscopy
• antigen-capture detection test

Question 13

Describe the 2014 Ebola outbreak

Answer 13

• negligence in public health strategies
  -failure of other countries to invest in strengthening capacities

Question 14

Where was the most recent outbreak of ebola?

Answer 14

Democratic Republic of Congo
2018-2022