Ta'lim innovatsiyasi va integratsiyasi
47-son_2-to’plam_Iyun -2025
233
ISSN:3030-3621
UDК 576.89
PARASITISM.
Fakhriddinova Sh.F
faxriddinova.shaxnoza@bsmi.uz
Bukhara State Medical Institute.
Summary
.
Helminthiasis constitutes the largest group of parasitic diseases.
They are caused by parasitic worms or helminths. More than 250 species of helminths
have been registered in humans. Of this number, about 30 are common human parasites
and form foci with significant infestation, and the rest are animal helminths that infect
humans more or less accidentally.
Keywords:
helmints, epidemiologi parazits.
Form of symbiosis is synoikia (syn-together, oikos-house, place). This is such a
coexistence that both animals living together can be neutral towards each other, or one of
them uses the other, but does not harm him in any way. Thus, one of the cohabitants slowly
serves the other and does not see any benefit for himself from such cohabitation.
Sometimes one of the cohabitants, due to his small size or very slow mobility,
climbs onto the div of the other cohabitant and lives with him as a companion. Such
relationships can be expressed by the general term “lease”. There are several types of
rental housing.
Simple rent - lives in the div of the owner or within the limits of his influence.
1. When living together in a rented apartment, one organism uses the other as a
home. For example, the mustard fish protects its eggs from enemies by placing the eggs
in the mantle of toothless bivalves, or the very small Fierasphere fish hides under the
umbrellas of jellyfish in case of any danger.
2. Epioikia - a tenant living on rent sits on his div and uses it as a means of
transportation. M: Crustaceans belonging to the genus Cirripeda cling to the bodies of
whales and sharks and use them as transport, while they themselves feed on plankton, or
sticky fish passively cling to the shark with their dorsal fin and feed on food left by the
sharks. . In this case, the sticky fish spreads to other places at the expense of sharks, which
is called epioikia.
3. Entoikia - along with sitting on the owner, it is used for feeding at his expense.
M: Fishes of the ammotid family live in the watery lungs of sea cucumbers, but can
sometimes go out into the water and feed on small crustaceans.
One of the main manifestations of synoikia is commensalism. In a commensal
relationship, one organism does not harm another organism by eating unwanted food.
Ta'lim innovatsiyasi va integratsiyasi
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ISSN:3030-3621
Forms of communication between parasites and hosts. Facultative parasitism is a
phenomenon in which some free-living organisms enter other organisms and survive.
Facultative parasitism is important in studying the origin of parasites.
When free-living organisms become parasitic, their structure and physiology
must have specific characteristics and certain conditions. M: Owners must have strong
skin, not exposed to digestive juices, and be able to live in anaerobic conditions.
In rare cases, false parasitism also occurs. In this case, some organisms
accidentally end up in the div of a second organism that has not adapted during
evolutionary development. But this organism cannot live in the div (for example, an
earthworm can come out of the intestines of vertebrates). If the larvae or eggs of various
flies and mosquitoes enter the human div through food, they cause various symptoms of
illness (diarrhea, nausea, vomiting and nausea).
Parasites are divided into temporary and stationary (permanent) depending on the
duration of their stay in the host’s div.
In temporary parasitism, the parasite temporarily
lives in the host’s div, feeds normally, but does not develop or reproduce. In this case,
there are no harmonic connections between the parasite and the host. The parasite enters
the host's div only during feeding.
These include many blood-sucking ectoparasites (mosquitoes, flies, ticks,
bedbugs, leeches, etc.). Stationary parasitism is studied in two ways. Periodic and
permanent. In periodic parasitism, parasitism occurs during the developmental cycles of
organisms. Some organisms parasitize during the larval period (larval parasitism, m:
mermitidae). Some of them parasitize in the adult period (imaginally) (m. nematodes -
Strongilidae).
Helminths are parasitic multicellular organisms belonging to the lower worms
of the Scolecida type.
Epidemiological features of helminth infections are determined by the biological
characteristics of helminths.
Non-contagiousness of helminthiasis. An infected person is generally not
contagious to others (with the exception of enterobiasis, hymenolipediasis; sometimes
- taeniasis, strongyloidiasis).
The disease is transmitted mainly through contaminated hands, unboiled water,
household items, and eating unwashed fruit. You can become infected anywhere if you
fail to follow basic rules of personal hygiene or careless attitude to nutrition.
Symptoms
of helminthic infestation are not always noticeable; for a long time, the disease can
masquerade as other problems. Detection of parasites during a medical examination or
targeted examination for suspected helminthiasis is a reason for treatment. The disease
is more common in children of preschool and school age and is manifested by the
following symptoms:
in children it begins with a decrease in appetite, nausea,
abdominal pain, the child becomes capricious, whiny, due to a disorder of the nervous
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ISSN:3030-3621
system, children stop growing mentally and physically; and sometimes convulsions
may also occur. In adults, allergic rashes, itchy skin, and allergic diseases are more
common.
The human div is an ideal habitat for parasites; they can live for years not
only in the intestines, but also in other organs (lung tissue, liver parenchyma, eyeballs,
skin, circulatory system, myocardium, brain), causing serious harm to health. The size
of these “illegals” varies from microscopic (protozoa) to tens of meters (tapeworms).
Taking into account mutual fitness, helminths and hosts are divided into two
groups: obligate and facultative helminths and, accordingly, obligate and facultative
hosts. An obligate helminth is one whose evolution is closely related to the evolution
of the host. Such a helminth has optimally adapted to the conditions of the biochemical
and biophysical environment present in the organs and tissues of a given host.
Outside
the div of a given host, the parasite would not be able to withstand competition in the
struggle for existence. The obligate host of this helminth is characterized by the fact
that it is in it that the parasite is ensured the greatest survival rate, the fastest and most
complete growth. An example of obligate parasites and hosts is humans and
roundworms.
Facultative parasites are those whose evolution occurred independently of the
evolution of the given host, therefore they are poorly adapted to the conditions of the
biochemical and biophysical environment present in the organs and tissues of the host.
Under these conditions, the facultative parasite has extremely low viability.
A
facultative parasite is found infrequently in the div of a facultative host and in most
cases in a small number of copies. Examples of facultative hosts and parasites include
humans and trichostrongylids.
The localization of helminths is very diverse. Helminths can parasitize almost
all human organs and tissues. The most common site of localization is the
gastrointestinal tract. The lungs are the site of localization of the parasite during
paragonimiasis and the site of temporary localization of the larvae of migrating
nematodes (ascariasis, toxacariasis, hookworm disease, etc.).
Echinococcus can
sometimes be localized in the lungs. Helminths can parasitize in the blood
(schistosomiasis, filariasis). The larvae of migratory nematodes, as well as a number
of helminths that parasitize humans in the larval stage in various tissues (echinococcus,
cysticercus, trichinella, etc.), can temporarily be present in the blood and spread
hematogenously. Some helminths (echinococcus, cysticercus) can parasitize the
central nervous system.
When the digestive organs are damaged, helminths are
characterized by strictly defined localization. In particular, bovine and pork
tapeworms, wide tapeworms and roundworms (in the mature stage) are fixed in the
upper part of the small intestine, dwarf tapeworm - in the lower third of it, whipworm
- in the large intestine, opisthorchis - in the bile ducts of the liver and pancreatic ducts.
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Some helminths can be localized in various organs. Thus, cysticercus can parasitize the
brain, eyes, intermuscular connective tissue and subcutaneous tissue, heart, and liver.
Echinococcus most often affects the liver and lungs, but can also parasitize the central
nervous system, genitals, kidneys, muscles, eyes, and sometimes other organs and
tissues.
There are intensive and multiple invasions. The intensity of invasion is
determined by the number of parasitic helminths of one species. It can range from one
to several thousand copies (ascariasis, enterobiasis, trichuriasis), even with invasion by
large helminths (wide tapeworm, etc.), the number of parasites can reach 10 or more.
Multiple infestations refer to the parasitism of several types of helminths. There
may be 2-3 or even 4 types of helminths. Simultaneous parasitism of more than five
species of helminths is very rare.
LITERATURE
List of basic literature:
1.
П. Мамчик
,
О.В. Каменева, И.В. Колнет, Н.В. Габбасова, О.А. Панина,
2.
С.Е.Савельева Учебное пособие по эпидемиологии для студентов лечебного
факультета2//2007
3.
Эпидемиология: Учебник. / Л.П. Зуева, Р.Х. Яфаев. - СПб : ООО «ФО-
ЛИАНТ», 2006. - 752 с.
4.
Инфекционные болезни и эпидемиология / В.И. Покровский и [др.]. - М. :
ГЭОТАР-МЕД, 2003. -816 с.
5.
Эпидемиология: учебное пособие./ Ющук Н.Д., Мартынов Ю.В. - М.:
Медицина, 2003. - 448 с.
6.
Шапошников А.А., Карниз А.Ф. Организация санитарно-гигиенических и
противоэпидемических мероприятий а чрезвычайных ситуациях на со-
временном этапе/А.А. Шапошников, А.Ф. Карниз - М.: Медицина, 2001.--304
с.
Список дополнительной литературы:
7.
Б.А.Ревич, С.Л.Авалиани. Г.И.Тихонова Экологическая эпидемиология.
Учебник - М: Издательский центр «Академия», 2004. - 53-86.
