Finkelstein,
You are asking “What happens when lighting strikes a forest full of tress and they all burn to their destruction, and why disease-causing viruses?”
Whether it is good or hurt, they come from multiple sources such as one’s own action, God’s over-all design of everything, and nature…etc.
If everyone is caring for each other, you will have perfect system of things on earth resembling heaven, with perfect climate with no such things as harmful lightening ..etc
If everyone is self-serving, you will have just opposite type of system things on earth resembling hell.
If people are mixed, then you will have another system of things befitting such a mixture.
Connection between our thinking pattern and responses of nature are becoming more pronounced these days. We destroyed the perfection of nature with our greed; we designed vehicles and factories with their toxinating pipes on to the air we breathe and water we drink. Human body is a micro universe and we see our bodies reacting according to the quality of our thoughts. Similarly thoughts of all human beings will have corresponding effects on the environment outside because both human bodies and nature outside are made with same physical elements. You can deduct these thoughts from this article. (https://www.scientificamerican.com/article/scientists-can-now-blame-individual-natural-disasters-on-climate-change/) In addition, climate change is now known to be increasing the cases of diabetes and other diseases.
Similar is the case with micro organisms causing diseases. We simply blame them. We are not bothered to find out why some doctors and nurses get affected by the viruses from the patients they treat and other doctors and nurses do not get affected by them. Viruses multiply in favorable environment. What makes favorable environment in some humans and unfavorable in other humans? It is obviously their habit. Why can’t such habits be made mandatory in every country like tax laws are mandatory which make provision to recover your any property in case of violation.
Micro organisms work to remove the wastes from the earth, and if wastes are found in human bodies they will find favorable atmosphere there to multiply themselves bringing the condition we call dis-ease.