Rheumatism symptoms have nothing to do with being bitten by fire ants. Fire ants, also known as red ants, are among the most common stinging ants, and are actually over a hundred different species of ants. There are some differences among the various species of fire ants, but I am not aware of the venom of any fire ant species causing joint pain and weakness. If you have been experiencing these symptoms, you should go to the doctor - whether or not they are due to the fire ant stings, they are not mild symptoms and should be attended to as soon as possible.
When fire ants sting, they inject a little venom, which causes the area to burn and sting. The area also swells a bit, and later sometimes turns into a pustule. The pustule can sometimes take a few weeks to disappear, and remains somewhat painful through most of this time. However, apart from an allergic reaction that some people experience, these are the only symptoms of fire ant stings. Even if you do have an allergy to the venom, this would only explain the swelling, and not any weakness. Allergies to venom can cause a variety of symptoms, but none of these are similar to rheumatism, and ant venom can certainly not cause rheumatism.
In addition, rheumatism is not really a disease but a colloquial term that is used to describe several diseases and medical conditions that have somewhat similar symptoms and are rather difficult to treat. These include spondylitis, fibromylagia, rheumatic fever, and most forms of arthritis, including rheumatic arthritis. Most of these disorders involve some kind of chronic pain and swelling of the joints or bones, and were earlier thought to be a single disease; now however we understand them better and are aware of the differences between them.
answered by G M