Ross River Virus

Question 1

symptoms of ross river virus

Answer 1

rash on limbs or trunks for 5-10 days; painful and swollen joints, usually lasting for months; fever and headaches.

Question 2

ross river virus pathogen type

Answer 2

RNA virus

Question 3

ross river virus mode of transmission

Answer 3

indirect via female mosquito vector e.g. Aedes vigilax

Question 4

Ross river virus life cycle specifications

Answer 4

Entry via skin (blood feed)
replication in epithelial cells of mosquito vector and muscle cells of the infected human host before entering the bloodstream and then multiplying there; the reservoir is marsupials (e.g. wallabies)
entry and exit via two different blood feeds; exit not likely from human host, pathogen circulates through marsupials such as the western grey kangaroo

Question 5

mode of transmission

Answer 5

Indirect
Requires a vector (mosquito)
Mosquito picks up virus from kangaroo/other marsupial which act as natural hosts
Human-mosquito cycle may occur in explosive outbreaks

Question 6

Method of Invasion

Answer 6

Genome composed of RNA
After mosquito bite, RRV are inoculated + attach to cell surface
Penetrates cell + is uncoated
Replication occurs as in influenza virus
Primary replication occurs in skeletal muscle
Enters the blood + then symptoms commence

Question 7

Impact on Host

Answer 7

Incubation period roughly 3-15 days
Joint inflammation and pain
Commonly wrists, knees, ankles + extremeties
Fatigue + muscle aches
Sometimes rash, enlargement of lymph nodes, pins + needles
Usually lasts a few months (but sometimes can last over a year)

Question 8

evolutionary adaptations

Answer 8

Utilizes a vector for transmission
Can be transmitted through desiccation-resistant eggs of Ochlerotatus mosquito
Persists in environment for long time + may explain rapid appearance after heavy rains

Question 9

Factors Affecting Spread

Answer 9

Epidemics usually follow heavy rains or high tides
Horses can act as amplifier hosts
Suppression of mosquito population through local control measures can decrease spread

Question 10

Management Strategies - Treatment

Answer 10

Rest advised in acute stages of disease
Paracetamol given for pain / fever
No specific antiviral treatment exists

Question 11

Management Strategies – Prevention

Answer 11

Mosquito control measures
Long loose clothing, insect repellants, avoiding mosquito prone areas and times
No vaccine currently available