Иностранный язык (английский). Учебное пособие

Well-nourished, healthy animals often tolerate considerable worm numbers without developing a disease.

Vocabulary list

alimentary adj - пищеварительный burrow v - внедряться, прятаться cestode n - цестода

feces n - фекалии fluke n - сосальщик helminth n - гельминт

helminthiasis n - гельминтоз hermaphrodite n - гермафродит larva (larvae) n - личинка

molt n - линька

nemathelminth n - нематогельминт, круглый червь nematode n - нематода

platyhelminth n - платигельминт, плоский червь proglottid n - проглоттид

scolex n - сколекс (головная часть) sucker n - присоска

tapeworm n - ленточный червь trematode n - трематода

Trichuriasis

Trichuriasis, also known as whipworm infection, is an infection caused by parasitic roundworms belonging to the genus Trichuris. Different species of whipworms infest different species of animals. The most important species inhabit the large intestine of cattle, sheep, goats, pigs, dogs, cats, and humans. Infection occurs worldwide in warm and humid climates and in temperate climates during warmer months, especially in areas where sanitation and hygiene are poor. The severity of the disease depends on the number of worms and the condition of the host. Adult worms are 3 to 8 cm long and have a whitish to yellowish color. Their shape resembles a whip with its handle, with posterior end thicker than anterior, hence the name

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“whipworm”. The worm’s body is covered with a cuticle, which is flexible but rather tough.

Similar to other nematodes whipworms have a direct life cycle. Female worms produce several thousand eggs per day. These eggs are shed with the host’s feces. Because of their resistance to cold and dry weather, the eggs can remain infective in the soil for years. Final host ingests eggs with contaminated food or water.The larvae hatch out of the eggs in the small intestine, enter the mucosa there and move forward to the cecum where they penetrate the mucosa and complete development to adults.

Immature larvae that penetrate the lining of the large intestine cause irritation. Later adult worms feeding on blood damage the wall of the cecum. Nevertheless, light infestations frequently have no symptoms. Massive infections can cause intestine inflammation (enteritis), ulceration, bleeding and subsequent anemia, bloody diarrhea, disturbed fluid absorption, dehydration, lack of appetite and weight loss. Some animals, especially the young ones, may even die.

Diagnosis is based on the detection of eggs in the feces. Adult worms may also be seen in the host's droppings.

Preventing whipworm infections in free ranging livestock is not an easy task: the eggs can remain infective for years on pasture and are extremely resistant to adverse weather conditions. Serious, live threatening infections do not happen too often. In confined livestock facilities, thorough hygiene measures including manure removal are highly recommended in endemic regions.

To prevent whipworm infections in dogs and cats daily removal of droppings is very important as well as frequent change of bedding (sawdust, sand, gravel) of playing grounds, runs, pens, cages, especially where numerous pets live together. Young animals must be particularly protected because they are more likely to suffer from whipworm infections.

Many anthelmintic drugs are effective against trichuriasis in livestock and pets. Unfortunately, animals that were successfully treated do not remain protected against new infections. Periodic deworming of animals may help to keep them worm-free.

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Vocabulary list

ranging adj - пасущийся run n - вольер

sawdust n - опилки trichuriasis n - трихуроз whip n - кнут whipworm n - власоглав

droppings n - помет, навоз

Foot and mouth disease

Viruses are important pathogens of livestock. Common infections include foot-and-mouth disease and bluetongue.

Pets like cats, dogs, and horses are also susceptible to serious viral infections. For example, dogs may be affected by rabies, canine parvovirus infections (fatal to puppies). Horses may be affected by the Hendra virus that is highly contagious and fatal.

Foot-and-mouth disease (FMD) is a highly infectious, notifiable, vesicular disease of domestic ruminants (cattle, sheep, goats etc.), pigs, other farmed cloven-hoofed mammals and wild ruminants. It is a significant economic disease due to its ability to spread very rapidly and its profound effect on productivity. A very small quantity of the virus is capable of infecting an animal, and the disease could spread rapidly throughout the country if it is not controlled quickly.

The organism, which causes FMD, is an Aphthovirus of the family Picornaviridae. Picornaviruses are non-enveloped, RNA viruses with an icosahedral capsid. Foot-and-mouth disease virus (FMDV), the first animal virus, was discovered in 1897.

There are 7 known types and more than 60 subtypes of the FMD virus. Immunity to one type does not protect an animal against other types or subtypes. Some strains can give rise to high levels of mortality in young animals. In adult animals, the disease is not usually fatal, however it causes severe pain and distress, especially in cattle, and animals may be left permanently lame with reduced productivity following recovery.

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The clinical signs of FMD are similar to other vesicular diseases and confirmation of diagnosis can only currently be made following laboratory tests. Cattle with foot-and-mouth disease may develop blister-like sores on the tongue and lips, in the mouth, on the teats and between the hooves.Vesicles rupture and discharge clear or cloudy fluid, leaving raw eroded areas surrounded by ragged fragments of loose tissue. Other clinical signs include: fever, shivering, lameness, slobbering and smacking lips, cows produce less milk. In sheep and goats, however, the disease is less severe or occurs as a sub-clinical infection. Sheep rarely develop blisters in the mouth as a result of foot and mouth disease. Blisters on the hoof are more common. In either location, the blisters tend to be very small and hard to spot.

Signs of foot and mouth disease in pigs include sudden lameness, which may spread quickly among the herd, tendency to lie down and unwillingness to move, reluctance to feed. Pigs don’t usually develop blisters as a result of foot-and-mouth disease. But sometimes blisters do appear on the snout, tongue and on the upper edge of the hoof where the skin and horn meet.

The virus is present in great quantity in the fluid from the vesicles, and it can also occur in the saliva, milk and dung. Contamination of any objects with any of these secretions or excretions is a danger to other susceptible animals. Heat and disinfectants will destroy the virus, whereas cold and darkness tend to keep it alive. Survival of the virus in the environment depends on a range of factors and is highly variable. Under field conditions, this can range from days to months. The virus can be transmitted on fomites (an inanimate object capable of transmitting infectious organisms from one individual to another, for example, vehicles and farm equipment), as well as mechanically by animals and other living vectors. Animals can pick up the virus either by direct contact with an infected animal, or by contact with foodstuffs or other things which have been contaminated by an infected animal, or by eating or coming into contact with some part of an infected carcasses. Airborne spread of the virus can also occur and, under favourable climatic conditions, the disease can spread several miles by this route.

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Relevant biosecurity measures should be practiced as a matter of routine. Trucks, lorries, market places, and loading ramps - in or over which infected animals may have travelled - are a disease risk until properly cleansed and disinfected. Roads may also become contaminated, and virus may be picked up and carried on the wheels of passing vehicles. The boots, clothing, and hands of any person who has been in contact with infected animals can spread the disease. Horses, dogs, cats, poultry, wild game and vermin may also carry infection. There is a range of regulatory measures to help reduce the risk of spread of any notifiable disease before it is detected (silent spread) and to help with tracing animals if any incursion was to occur. These include requirements for cleansing and disinfecting livestock vehicles.

Vaccines for FMD are available, but must be matched to the specific type and subtype of virus causing the outbreak. Although these vaccines are very useful as part of eradication campaigns in countries where FMDV is enzootic, it is not feasible to use these products in prophylactic vaccination of entire regions.

Vocabulary list

blister n - водяной пузырь, волдырь bluetongue n - катаральная лихорадка овец cloven-hoofed adj - парнокопытные cloudy adj - мутный

eroded pp - эрозированный

feasible adj - возможный, целесообразный fomites n - абиотическая среда foot-and-mouth disease - ящур

incursion n - начало заболевания lameness n - хромота

myxovirus n - миксовирус slobbering n - слюнотечение snout n - рыло, морда

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sore n - нарыв, рана strain n - штамм

Picornaviridae - пикорнавирусы pneumonia n - пневмония smacking n - причмокивание vermin n - вредитель, паразит

vesicular adj - везикулярный, пузырчатый vesicle n - пузырёк, везикула

Fascoilosis

Fasciolosis is a parasitic worm infection caused by two trematodes Fasciola hepatica and Fasciola gigantica. Adult flukes of both species are localized in the bile ducts of the liver or gallbladder of numerous domestic and wild mammals. They have an indirect life cycle with a snail as an intermediate host.

The common liver fluke occurs worldwide but is particularly abundant in humid regions with temperate climate where it can be endemic. It is one of the most damaging helminth parasites of grazing ruminants. It is particularly harmful, even fatal for sheep. Prevalence and incidence in a particular region depends strongly on ecologic and climatic conditions and on livestock management practices.

Adult liver flukes have a flat body, an oval shape, and a pinkgrayish to dark red color. Liver flukes have two suckers, both in the ventral side. The body surface is covered with numerous spines. Adult flukes produce eggs in the bile ducts of their hosts. These eggs reach the gall bladder, pass to the host's gut, and then are expelled with feces.

Once outside the host, the larvae called miracidia hatch out of the eggs in 7 to 15 days. These larvae can survive for weeks off a host if there is enough humidity. They can swim and penetrate actively into the snails where they remain for 4 to 8 weeks and develop successively to sporocysts, rediae and cercariae, the usual larval stages of most fluke species. A single miracidium can asexually produce up to 600 cercariae.

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Mature cercariae leave the snail, attach to the vegetation, lose their tail and produce cysts of about 0.2 mm, the so-called metacercariae, which are infective for the final host. Such cysts can survive for months in the vegetation, even under dry conditions. Livestock becomes infected by grazing on contaminated pastures or eating infected hay.

Liver flukes are very harmful for their hosts, particularly for sheep. Young immature flukes migrating through the liver tissues and crossing the wall of the bile ducts cause the major harm. This process destroys the tissues and causes bleeding. The spines on the surface of the flukes irritate the tissues that become inflamed. All this leads to cell death and fibrosis. Affected livers increase in size and become fragile. Some flukes can become encapsulated in the liver tissues and build cysts as large as walnuts. The bile ducts are also damaged: they become thickened and can be calcified and even obstructed. Infections with secondary bacteria can also happen, mainly due to the general weakness of the host. In addition, flukes produce own toxins that impair the normal function of the liver.

Besides fatalities, the major economic damage is the reduced weight gains of young animals (up to 30 % less, even after slight infections) and the condemnation of livers at slaughter. Light infection can reduce milk production in dairy cattle.

There are no really typical and easily recognizable symptoms of a liver fluke infection in livestock or other animals. The major symptoms are related to the inflammation of the liver and of the bile ducts. Infections with a few dozen adult flukes may not cause clinical signs other than general weakness and reduced productivity.

Chronic fasciolosis in sheep, goats and cattle develops along the gradual establishment of adult flukes in the bile ducts. It is characterized by the progressive development of such symptoms as anemia, edema, digestive disturbances such as diarrhea or constipation, and emaciation.

Acute fasciolosis is seldom in cattle but can occur in sheep. It is caused by the sudden migration of many immature flukes through the liver, which leads to complete organ failure. Animals may be killed in a few days.

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Diagnosis is based on feces examination and immunological methods. Clinical signs, biochemical and haematological profile, season, climate conditions, epidemiology situation, and examinations of snails must be considered as well.

As Fasciola infection is almost impossible to eradicate in endemic regions, preventive measures have to deal with reduction of the snail population and keeping the pastures dry. To diminish fluke infestation rotational grazing is highly recommended.

Vocabulary list

fasciolosis n - фасциолёз cercaria (cercariae) n - церкария constipation n - запор

eradicate v - искоренять

miracidium (miracidia) n - мирацидий obstruct v - закупоривать

redia (rediae) n - редия sporocyst n - спороциста

Tricky words

1.Illness is generally used as a synonym for disease. However, this term is occasionally used to refer specifically to the patient's personal experience of his or her disease. In this model, it is possible for a person to have a disease without being ill, and to be ill without being diseased (for example, a person who feels unwell as a result of embarrassment, and who interprets those feelings as sickness rather than normal emotions).

2.Malady – any disorder or disease of the body, especially one that is chronic or deep-seated; any undesirable or disordered condition: social maladies, a malady of the spirit.

3.Sickness – a particular disease or malady, the state or an instance of being sick; illness; nausea; queasiness.

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4.Disorder. In medicine, a disorder is a functional abnormality or disturbance. Medical disorders can be categorized into mental disorders, physical disorders, genetic disorders, emotional and behavioral disorders, and functional disorders. The term disorder is often considered more value-neutral and less stigmatizing than the terms disease or illness. However, the term disorder is also used in many other areas of medicine, primarily to identify physical disorders that are not caused by infectious organisms, such as metabolic disorders.

5.Ailment – a physical disorder or illness, especially of a minor or chronic nature.

6.A medical condition is a broad term that includes all diseases, lesions, disorders, or non-pathologic condition that normally receives medical treatment, such as pregnancy or childbirth. The term medical condition is also a synonym for medical state, in which case it describes an individual patient's current state from a medical standpoint. This usage appears in statements that describe a patient as being in critical condition, for example.

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БИБЛИОГРАФИЧЕСКИЙ СПИСОК

[Текст] / Л. Н. Пудовкина. – Астрахань: Астраханский государственный университет, Издательский дом «Астраханский университет», 2011. – 81 с.

Войнатовская, С. К. Английский язык для зооветеринарных вузов [Текст]: учеб. пособие/ C. К. Войнатовская. – СПб.: Издательство «Лань», 2012. – 240 с.

Кайдалова, О. И. Veterinary Science: Overview of Infections

[Текст]: учеб. пособие/ О. И. Кайдалова, Е. А. Барляева, Н. Л. Короткова, О. А. Логинова. – СПб.: Издательство

доступа: http://biblioclub.ru/index.php?page=book&id=111931

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