Are there specific causes for a specific disease or illness or cause of death that can be attributed to kamma earned in one of previous lives for a given person? For instance, if a person is suffering from cancer or heart attack, is there a cause in the kammic history that he/she might have earned? And what about causes of unnatural death in an unintentional manner? The question that I am posing is, I know that not all causes of disease/death are caused by past kamma, But are there kammic causes for the rest of the events that cause disease/ailment/death in the present life?
I will attempt to answer this question. I think one of the misunderstandings of karma arises from the analogy of planting of seeds to describe good or bad karmic fruits. Good seeds lead to good karmic fruits but bad seeds lead to bad karmic fruits. A result of such simplification is that a particular seed will lead to a particular fruit, right? Mango seeds eventually results in mangoes while lemon seeds results in lemons. It is not so exact such that one suffering from cancer now is a result of causing cancer to another in some previous existence.
When a karmic seed (good or bad) is planted, it generates a force which will manifest in a future time and place. The exact form which this karmic force manifest would be a probability depending on the context of that future time and place. If a person was to be born in an advanced era where all types of cancer and disease are curable, then the likelihood of them dying from any disease is low. However, a bad karmic force would still want to manifest in other ways if not by disease, then by others e.g. accident or homicide.
An example is the precautionary tale of the limitations of supramundane powers. In the story, Venerable Mogallana tried to save five hundred Sakyas but failed. The Sakyas did not died in the hands of their enemies through battles but instead from a divine feat that went haywire.
In short, the effects of karma are multi-dimensional with a certain probabilistic tendency (from low to certainty). And it will still manifest in other dimensions even if you manage to somehow block its effect in one dimension. I am afraid you will need to find someone accomplished in the supramundane powers like the divine eye faculty and wisdom to truly understand the cause of a particular karmic effect. Not that it will be helpful because once a severe and bad karmic force manifest, even those with supramundane powers are helpless against it. This is illustrated by the death of Venerable Moggallana at the hands of brigands through a sudden loss of his supramundane power.
The exact workings of kamma are imponderable (AN 4.77) for everyone but a Buddha. We know general trends like not killing creatures leads to a long life. MN 135
Kamma is also not the only factor. If a hurricane hits Haiti, did everyone who die have bad kamma? Probably not. And based on their kamma they'll have different types of rebirths.
Karma is only one of the five niyamas (orders or processes) that condition the universe according to Theravada Buddhism. The others include biological processes (bijaniyama), physical processes (utuniyama), psychological processes (cittaniyama), and natural or seasonal processes (dhammaniyama).
So while kamma can influence our lives, not everything is a result of kamma. The Buddha himself cautioned against trying to work out the specific workings of kamma, as it is "imponderable" and can lead to confusion and misunderstanding.
From a scientific viewpoint, diseases such as cancer or heart attack have known biological and environmental causes. For instance, cancer can be caused by genetic mutations, some of which may be inherited, while others may be triggered by environmental factors like exposure to certain chemicals or radiation. Heart attacks are often caused by lifestyle factors, such as poor diet, lack of exercise, smoking, or by conditions like hypertension or diabetes
Please see the answer to a similar question by a Buddhist Monk (Bhante Gunaratana):
https://www.youtube.com/watch?v=rslQg-CIQH8 Time: 16:19
There are several types of diseases. Diseases of mind or brain, diseases of eye, diseases of ear , diseases of tongue, diseases of nose , diseases of teeth , diseases of blood , diseases of bones, diseases of kidney , diseases of intestines, diseases of heart , diseases of liver , diseases of joints etc etc. Some diseases occur naturally due to malfunction of organ. As you grow old some diseases manifest naturally due to ageing. Ageing is inevitable because all conditionings are impermanent. There are diseases due to volitional formations or karma. A mosquito bite might result into dengue or malaria. Virus, bacteria and fungus may cause diseases like coronavirus.Are the diseases because of your karma ? On this question dependent origination is the answer. There was ignorance which led to volitional formations which led to consciousness which led to name and form which led to six sense organs which led to contact which led to feelings which led to cravings which led to clinging which led to attachments which led to becoming which led to the birth , ageing and death of disease.
Same applies to birth of earthquakes , floods and hurricanes…