It was traditionally believed that infectious diseases could be acute or chronic
Honored doctor of the Russian Federation, chief infections expert with the RF Health Ministry, head of the infectious diseases chair at the Russian Medical Post-graduate Academy Professor Mels Turyanov tells how present-day medicine can fight infections.
-Some time ago, doctors believed they were about to fight infections; however, today the situation has changed. Why?
Doctors have been working on methods of liquidating infectious diseases within the 20th century and scored victory after victory in this sector. They believed that effective vaccines and general vaccination of the population were the instruments to control some particular infectious disease. It was even declared that some infection might be liquidated absolutely.
Unfortunately, it is perfectly clear today that liquidation of any infection is just an illusion. Total control over some infection is a hard thing to do as well. That became evident in 1991 when a sweeping diphtheria epidemic broke out in Russia. The disease was considered as thoroughly controlled at that time. The epidemic coincided with the break-up of the USSR and the collapse that it entailed, which was not accidental at all. The disease was to some extent provoked with stress, poor living conditions and other factors weakening the immune system.
- Do you mean that an epidemic of any disease, even smallpox, may break out any time?
It is not ruled out. Some time ago it was believed that smallpox pathogen existed and developed in the human organism only. But as it turned out later small rodents may spread smallpox as well. It is an open secret that South America brush tail rats (Octodon degus) can accumulate the smallpox virus in their organisms. It is dangerous for people to get into the area where the rats live. Besides, two research laboratories, in Russia and the USA, also keep the living smallpox virus; it is not ruled out that some other laboratories also have it. The virus may become a dangerous weapon in the hands of some biological terrorist. Especially that no vaccination against smallpox has been done in this country since 1980.
Today, the incidence of acaridan encephalitis and Crimean hemorrhagic fever is impressive enough, even though that the diseases were taken control of many years ago.
- Let us speak about new diseases that nature causes today.
It depends what diseases we consider to be new. In most cases, doctors were perfectly aware of symptoms of some diseases long ago, but they knew nothing about pathogens of these diseases. Consequently, there was no opportunity to cure them. Over fifty pathogens have been discovered over the past 30 years.
Let us take hepatitis, the disease known as jaundice or the disease of dirty hands. Besides hepatitis A (the pathogen of the disease makes skin yellow when it leaves the organism), there are hepatitis B, C, D, and today there are eleven forms of the disease. Hepatitis C is the most serious among them and is as dangerous as AIDS. People suffering from hepatitis C will see its dangerous effect in the future: patients will die of cirrhosis in 25-30 years when liver cells get substituted with scar tissues.
In other words, now we see that the list of traditional infectious diseases that medicine can fight may even increase. This will make diagnosing and making vaccines more difficult.
Recently, the World Health Organization conducted a research. Researchers took samples in volcano craters, in oceans, jungle, taiga, rivers and lakes, from the surface of plants and animals. They employed modern equipment and technologies for analysis of the samples and made up a shocking conclusion: the microbiology has discovered just 0.4 per cent of the entire microbe variety over the 120 years of its existence.
Researchers have made some other important discoveries over the past years. As it turned out, there are 10 foreign microbes per every cell in the human organism. So, people cannot live without certain microbes; some microbes are really dangerous for us and other neutral microbes may become destructive in case the immune system gets weaker. The research of the human genome (it makes up about 100.000 genes) revealed that one per cent of the genes looked very much like retrovirus. As we know, the dangerous AIDS pathogen is a retrovirus as well.
- Mass media report that there are some slow infections. Are they something new in the microbe world?
No. We know some of them very well, however they have turned out to be even more dangerous then we believed. It was traditionally believed that infectious diseases could be acute or chronic; and that the immune system clears the pathogen out of the organism as soon as a patient recovers.
As it turns out now, pathogens may stay in the human organism even if a patient recovers after an infectious disease. They may live and reproduce themselves in the organism within years. People sometimes even do not suppose such pathogens live in their organisms. But suddenly they fall ill with serious diseases that often have nothing to do with the previous disease. People may die or become invalids because of slow infections.
Doctors are just opening up slow infections and try to find more facts to prove that some pathogens may cause serious diseases. About 50 viruses are known today as causing serious diseases.
For example, if a baby gets infected with measles before 1.5 years it is not ruled out that the virus may stay in his organism within 8-10 years more after the baby recovers from the disease. As a result of the virus' staying in the organism, the child may suddenly fall ill with a dangerous brain disease. Women should be particularly careful of infections during pregnancy. Young people must get cured of infections (syphilis, gonorrhea and others) before having babies. But some dangerous viruses cannot be controlled yet. A woman may be a carrier of hepatitis B and feel absolutely healthy at that. But the virus will inevitably get into a baby's organism if the woman becomes a mother. The baby will seem healthy, and nobody will suppose the disease is slowly developing in his organism. Hepatitis may become more intense by the age of 25-30 when the man will die of cirrhosis. At that, the mother may never know that the son died because of the virus that had got into his organism from her. Helicobacter microbes cause slow pathologic processes that result in ulcer or stomach cancer. Recently, the World Health Organization published a report “Infectious agents and cancer” saying that 87 per cent of cancer diseases are connected with some infections, and are the result of slow infections.
We know that majority of cancer diseases require no operations; it is more important to diagnose the disease correctly and prescribe effective antibiotics to kill the pathogen of the disease. The World Health Organization claims that prophylaxis of helicobacteriosis, hepatitis B and C will reduce the cancer incidence by 15 per cent and save 1.5 million of people.
Many people on the planet die from atherosclerosis. It has been proved that atherosclerosis in various parts of the human organism is to some extent connected with chlamyda pulmonis, the bacterium earlier known as a pathogen of trachoma. This discovery provides new opportunities for prophylaxis of infarcts and insults.
- So, do the discoveries in the virus science give good hope for the future?
I would like to touch upon prion infections here. These are extremely severe diseases that destroy neurons and turn the human brain into a sponge. They also cause degradation and soon death. The disease is caused with a special protein, not a bacteria or a virus.
Scientists say that development of prion infections is similar to natural ageing of people. In other words, we may say that ageing is a slow prion infection as well: some particular gene causes production of prions and destruction of the organism may begin in some time. Being aware of the phenomenon, Japanese doctors have developed a program for prophylaxis of ageing and prolongation of human life up to 180 years. And this does not sound fantastic indeed.