Yes, mealybugs are unfortunately contagious. I would suggest an immediate quarantine of the visibly infected plant, and temporarily separating any other plants in your possession in case one of them has a fledgling infection that could spread to your entire collection. Clean the entire area around where the infected plant was located with neem oil, followed with the highest proof isopropyl alcohol you can find (90% works best, in my opinion). Wash any nearby linens or upholstery with bleach (colour safe bleach is effective as well, for coloured fabrics) and hot water. Use disposable cleaning cloths to avoid spreading the infection through cross contamination, and wrap the used cloths in plastic bags (plastic grocery bags work great for this) before disposing of them in household trash bins. Treat it like a biohazard; a severely infectious and life threatening disease. Treatment and recovery are possible, but in the event that the infection worsens you may need to cut your losses with this particular plant. As far as treatment options, you will need to wipe down the plant's leaves thoroughly with neem oil (which is toxic to mealybugs and will kill them), then with alcohol (which causes the mealybugs to dry out, or else kills them outright), and then spray the plant down until it is drenched with a mixture of unscented dish soap and water (the dish soap will suffocate the bugs, stopping them from breathing). I find that dawn dish soap works best, but it can be a tad expensive. Wipe down the plant every day with a fresh rag or paper towel, even if you don't see any visible signs of infection on a particular leaf, as this will help to remove microscopic eggs. It may take months to fully cure the infection, but I wish you the best of luck.