John's corrections from above are pretty spot on, so I'll just add something that you didn't quite figure out:

It's frown on to her means to handle this situation, those means seen as sin.

In this sentence I believe you are using "means" as a synonym for "methods" or "designs". We have a phrase in English that goes, "a means to an end," which means a method (a means) to accomplish a goal (an end). If I'm guessing correctly, then your sentence would suddenly make a lot of sense if I wrote it like this:

It's frown on to her methods to handle this situation, those methods seen as sin.

It's still not correct, but at least now the sentence makes some sense. So, if this is close to your meaning, then I would make the following correction:

Her methods for handling this situation are frowned upon. They are seen as sin.

I don't know if you were trying to learn how to use "means" or "frowned on". For "frowned on" the above statement works well. If you were trying to learn "means", the statement would need to go more like this:

When she handled this situation, people frowned on her means and saw them as sin.

Sentence-making

Making sentences

It's an urgent task for human kind to eradicate some viral diseases.

Eradicating viral disease is an urgent task for humankind.

Some parasitic diseases, living in the host and affecting the normal function of the host, do extreme harm to humans.

Parasites, which live inside the host and affect the host's normal functions, do extreme harm to humans.

It's frown on to her means to handle this situation, those means seen as sin.

(Does not make sense.)

Parasitic diseases on human beings are responsible for millions of people's death.

Parasites are responsible for millions of human deaths.

Transmissible diseases maybe the most destructive diseases in the world because they can have serious influence on a very increasingly large region.

Contagious diseases may be the most destructive because they can seriously influence a very large area.

Sometimes, Chasing down all the rare cases of the disease is not worth.

Sometimes, it is not feasible to completely eliminate every single case of a disease. (I think that's what you mean.)

Malaria can bounce back because it can evolve resistance to the drugs and the mosquitoes, its hosts, can develop the resistance to insecticides.

Malaria can bounce back because it can evolve resistance to drugs, and the mosquitoes that transmit malaria can develop a resistance to insecticides.

A necessary ingredient to the conquer of HIV is a reliable vaccine.

A necessary step toward conquering HIV is developing a reliable vaccine.