Both malaria and HIV are treated as highly dangerous diseases, in the first place, because of high mortality rates among the patients and then because of resistance to the existing treatment. Currently, pathogens of numerous other viruses evolve and present a challenge to the scientists, but malaria and HIV demonstrate that scientific mind is not yet ready to combat the dominance of tiny natural particles in the human body.
By this time, several generations of vaccines against HIV have been developed in the laboratories. However, they appeared to be ineffective and are used rather as hints to the further research. Scientists conclude that HIV is a very cunning organism which quickly transforms and disguises from the human immune system. Which is more, the effect of vaccines cannot be fully studied on animals. Today, researchers use monkeys infected with the artificial analog of the virus, but still it has not exactly the same effect on the animals as HIV does on humans.
Malaria is another notorious disease which annually kills up to a million people around the world most of whom are children. Being increasingly adaptive to the environment, malaria does not allow scientists to develop a vaccine which can help to all humans. However, once the incidence of the disease was diminished by the use of DDT pesticide which kills mosquito transmitting the protozoa. The improvement was dramatic in places where the substance was sprayed, but due to the claims of environmentalists the substance was banned from use in many countries.
As it is yet impossible to create vaccines against malaria and HIV, scientists do their best to combat the lethal consequences. Thus, the efforts of biologists in treating HIV ended up with creating the antiretroviral therapy which restrains the virus from multiplication and developing into AIDS.