This condition in the photo is not a disease. It is caused by an insect that, during its immature stages, burrows (“tunnels”) in the leaves. The insect is called a Citrus Leaf Miner. When it becomes an adult and exits the tunnels, it is a moth. Although the burrowing causes the leaves to become distorted, the leaves still provide food for the plant, so you should not remove them. There will not be any lasting damage from this insect. There is not any spray that can prevent this, because the insect larva is protected inside the leaf. The best way to reduce the infestation is to not fertilize your citrus during summer or fall, since this is the time the moth is active. Fertilizing causes new growth, and the new leaves are much more susceptible to the Leaf Miner than older, hardened leaves. Citrus should also not be pruned during this time, gain because pruning also causes new leaves to emerge.
Citrus should be fertilized before bloom (January or February), and again in May. If fertilizer is needed (e.g., if the leaves are not a deep green color), apply additional fertilizer no later than June. Always follow label directions when applying fertilizer. More recommendations regarding fertilizer for citrus can be found here.
Additional information about Citrus Leaf Miner can be found at this University of California website.
Photo courtesy of UC Davis