Where do ticks come from
Content
Ticks appeared on Earth many tens of millions of years ago, being contemporaries of giant reptiles, and have changed little since then. With high probability, even then in the Akari subclass there were species feeding on the blood of a dinosaur. This may be an indirect confirmation of the warmth of the lizards. The continents at that time were still a single whole, which allowed the ancestors of modern ticks to spread throughout the planet.In the process of evolution on already separate continents from the original, new types of ticks appeared, forming a phylogenetic tree. Therefore, the question of where the ticks came from in Russia is not legitimate. They existed on this territory long before the appearance of states and even a reasonable person. But the legality of the presence of ticks on the Russian territory is of little concern to people, since the main concern of mankind today is the fight against the diseases tolerated by these arthropods. So, the elucidation of the origin of tick-borne encephalitis is much more relevant than their evolutionary history.
The history of encephalitis tick
It is believed that up to the mid 30s of the last century, encephalitis did not exist on the territory of Russia and the Far East. And only after these years the encephalitic tick spread throughout Eurasia. There are two theories that answer the question, where did encephalitis ticks come from.
Conspiracy
This is all the Japanese to blame. In the 1930s, outbreaks of an unknown disease were observed in the Far East. The epidemic raged among the Far Eastern grouping of the Red Army.
The disease was first described in 1935 by A. G. Panov. In 1937 an expedition was sent there to find out the source of the infection. The expedition was headed by Professor LA Zilbert The work of the expedition was crowned with success and the vector was found. It turned out to be an ixodic taiga tick.
Since 1935, a laboratory for the production and testing of biological weapons operated by "Detachment 731" operated in the territory of Manchuria. After the Soviet Union entered the war with Japan, the work was curtailed and the laboratory was destroyed. It was not possible to completely trace the traces, after the surrender of Japan, it turned out that in the laboratory they worked with various viruses, using various objects as carriers. Starting with rats and ending with mosquitoes.
On a note!
The Japanese worked with encephalitis. But the strain of the virus was one that mosquitoes carry. The Japanese got it from mosquitoes. In the 1920s, an outbreak of mosquito encephalitis occurred in Japan, as a result of which several thousand people died. Mosquito encephalitis is a relative of tick-borne, but the strains are still different.
After returning to Moscow, the leader of the expedition to the Far East was arrested.The charge was brought against a Japanese saboteur who brought tick-borne encephalitis to Russia.
Inconsistencies
The Japanese worked with mosquito encephalitis, which is different from tick-borne. Travelers to the Far East still in 20 years (10 years earlier) indicated that the local population is afraid of ticks. Indigenous people are more resistant to tick-borne encephalitis.
On a note!
Wildlife is a carrier of the virus, but it does not get sick. This indicates that the virus appeared in the taiga long before the arrival of a person.
Encephalitis is a very unreliable biological weapon:
- it causes serious consequences only in 20-30% of cases;
- even in disadvantaged areas, only 20% of ticks are infected with the virus, and in less prosperous ones;
- virus is not transmitted directly from person to person;
- it is impossible to force an encephalitic tick to attack a person.
It is easier to use plague-infected rats and fleas instead of ticks. It was these vectors that the Japanese actually used.
The one who invented ticks, specially infected with encephalitis, pursued other goals: to remove a competitor. Regarding the alleged lack of encephalitis on the territory of Russia until the 1930s, one can do without conspiracy theories.
Before the Great October Revolution, the tsarist government was not particularly interested in the state of affairs in the Far East. This region was the site of an honorary exile. Sometimes not honorable, but just links. It is highly likely that people had encephalitis. But since at the first stage of development this disease is very similar to the flu or the common cold, it was diagnosed in this way, unable to do blood tests.
Interesting!
Encephalitis at the time "passed" in medical diagnoses as "toxic flu."
After the first stage of the disease, remission occurs (the person is recovering), and the second stage occurs only in a third of patients. And few of the patients recalled a tick bitten him a month ago.
Only when the “flu” began to mow down the military units, that is, organizations where there are a lot of people and everyone is in sight, management and doctors suspected that the cause of the epidemic was not in the usual infectious diseases and started looking for the source of the disease.
Modern genetic
The development of science and genetic research has allowed scientists to trace the origin and distribution of various animal species.But with ticks and encephalitis, everything just got more confused.
The most popular version of the spread of encephalitis today claims that the disease in the Far East has always been. In the villages she was ill, but they did not understand what it was. With the beginning of the active development of the eastern part of Russia, cases of the disease became more frequent, and encephalitis began to spread to the West. The first case of the disease in Europe was recorded only in 1948 in the Czech Republic.
But in 2012 at the international conference in Irkutsk, Novosibirsk scientists expressed the opposite point of view. In their opinion, based on the analysis of a fragment of a nucleotide sequence, encephalitis spread from west to east.
There is also a compromise point of view, the authors of which, based on the analysis of genome-wide TBE sequences from GenBank, are considered the origin of encephalitis Siberia. The spread of the disease, in their opinion, went in parallel in both directions.
In their arguments, the authors of hypotheses use the same nucleotide chains and the same software to determine the time of the onset of the virus.
On a note!
The time of occurrence of the virus according to these hypotheses also varies greatly: from 2.25 to 5-7 thousand years. The Japanese have nothing to do with it.
Given the resistance of the wild fauna to the virus and the rather narrow band of virus spread, despite the fact that the ixodidae themselves do not live in ices, we can conclude: the spread of the virus to the north and south is hampered by some natural factor. In the case of artificially created biological weapons, such factors do not work.
Another expedition of the late 30s revealed 29 virus strains that exist in the wild. For biological weapons, such diversity is also uncharacteristic.
Therefore, the hypothesis of self-induced encephalitis in the forests of Eurasia looks more consistent. And from where, where the virus actually spreads, is it interesting only to scientists. Ordinary citizens are much more concerned today with the question of where ticks come from in such huge numbers.
How are you doing with encephalitis today?
If you stick to conspiracy theories, then the plot is much easier to see in today's explosion of the number of ticks. Even in the area of encephalitis, 40 years ago, precautions were taken more for reinsurance. “Finding” a tick in the forest was difficult. Today on 1 square. km, the researchers removed 40 pieces. arthropods.And ordinary citizens complain that after each outing for a walk with a dog, at least 5 of these arachnids are removed from it and from themselves.
Where there is no encephalitis, piroplasmosis is rampant. And the number of ticks infected with this disease significantly exceeds the number of encephalitis.
On a note!
Such an outbreak of numbers occurred due to the ban on DDT and the complete cessation of the treatment of forests with insecticides. Insecticides harmed nature by destroying all insects, but they held ticks in check. Today, the arthropod population is multiplying uncontrollably, and encephalitis is slowly creeping into new regions of the country.
If the treatment of forests with pesticides is not restored, then all hope remains only for the very natural factors that restrained the spread of encephalitis before the invention of insecticides.