This is a great question. As symptoms from viruses that cause back pain are quite varied, I will specifically refer to Ross River Fever in this article.
Ross River Fever is the most common disease in Australia spread by mosquitoes biting an infected person, or an infected animal such as a kangaroo and then biting a non-infected person. About 5,000 new cases are reported each year in Australia. There are many such mosquito-borne diseases around the world and viruses transmitted in this fashion are called arboviruses. The disease itself is sometimes called epidemic polyarthritis and the virus belongs to the group called alphaviruses (one of the Togaviridae viruses).
Symptoms include painful joints, arthritis, rash, fever and fatigue and can persist for several months. The initial (acute) symptoms include joint pain in 95% of cases and this is usually symmetrical (involving left and right sides). Fingers, wrists & elbows, and toes, ankles & knees are the most common joints affected. I could not find published medical reports of it causing low back pain or spinal pain. About 50% of patients will also develop one or more of the following: joint swelling, fever, muscle pain (also called myalgia), rash, and headache. About 90% of people infected will also develop tiredness (lethargy). Ross River Fever has also been reported to cause conjunctivitis and eye pain. More detailed information has reported that fever occurs in 20 to 60% of patients; painful joints in 80 to 100% of patients, and myalgia in up to 80% of infected people.
Although symptoms resolve in the majority of patients at around 6 months, this is not always the case. Joint pain persists in about 70% of patients for more than 3 months after diagnosis, with most having their symptoms decreasing during this period. About half of those patients with symptoms persisting at the 6 month mark also had other conditions not caused by the virus, such as depression and rheumatological diseases. These patients may have problems even 12 months after diagnosis, whereas only 1 out of 60 patients who only had Ross River Fever still had symptoms at the 12 month mark.
Unfortunately there is no known treatment that will alter the duration of the disease, though there are treatments that can lessen the symptoms. Such treatments include analgesics (pain killers) such as paracetamol, and anti-inflammatory medications such as ibuprofen.
Wearing mosquito repellant, long sleeves and taking other personal protective measures to decrease mosquito bites are an important prevention strategy. As there are about 30 different species of mosquitoes that transmit the disease, it is necessary to avoid as many mosquito bites as possible.
Getting back to the lead question: How do I know if my present back pain or other joint pain is caused by Ross River Fever Virus? If you have back pain or other joint pain more than 6 months after being diagnosed with Ross River Fever, and this pain went away for several weeks towards the end of 6 month period before it returned, and you don’t have some other unrelated condition such as rheumatoid arthritis or depression, then chances are your existing joint pain is not caused by Ross River Fever Virus.
JF Farmer & A Suhrbier, Interpreting paired serology for Ross River virus and Barmah Forest virus diseases, Australian Journal of General Practice, 2019, 48(9) https://www1.racgp.org.au/ajgp/2019/september/paired-serology-for-ross-rivervirus-and-barmah-fo