A horizontal stripe usually indicates a problem with the CCD sensor assembly.
I don't think a SD card can cause that type of problem.
If the camera has been exposed to moisture, that can cause corrosion on any of the printed circuit boards. And it usually shows up on the CCD assembly.
There is nothing you can do to fix it.
Keep an eye on it and if it gets worse, you need to get a repair estimate from Casio.
I have been using PNY 4 GB SD Memory Cards for over a year and have taken hundreds of photos. Suddenly, on 2 photos, I got a thin pinkish stripe running horizontally from left to right. In 1 case, the stripe was near the top while on the other, the stripe is near the bottom. Then, the stripe is gone. What could be the cause? Is it a defect on the SD Card or on the camera? I've never seen this before. The camera is Casio Exilim EX-Z300.