Exercise 1. Match each term with its definition.
| 1. trophozoite | a) stomach-like compartments in protozoa |
| 2. cyst | b) microscopic unicellular eukaryotes that have a complex internal structure and carry out complex metabolic activities |
| 3. amoebae | c) active, feeding, multiplying stage of most protozoa |
| 4.vacuole | d) group of protozoa that use pseudopodia to move or crawl across solid surfaces |
| 5. protozoa | e) stage of protozoa with a protective membrane or thickened wall |
Exercise 2.Complete the following sentences. Choose the ending according to the text.
1. Protozoa are ….
2.Unlike the relatively simple bacteria, ….
3.They are named protozoa because ….
4.Based on the type of nutrition, protozoa can be classified into ….
5.Trophozoite is a general term for ….
6.Cysts are stages ….
7.Four main groups of protozoa are recognized on the basis of their locomotion. They are ….
Exercise 3. Give the English equivalents of the Russian words in brackets.
1. Protozoaare (микроскопическиеодноклеточныеэукариоты) thathavea (сложнаявнутренняяструктура). 2.Somespeciesofprotozoahavestructuresthatare (аналогичныйротовойполости, пищеварительномутрактуианусу).3.Basedonthetypeofnutrition, protozoa (можноклассифицировать) intoa) free-livingprotozoa, which (поедать) particulatessuchas (бактерии, дрожжи, водоросли) andb) parasiticprotozoa, whichgettheir (питательныевещества) fromthe (жидкоститела) oftheirhosts.4.Duringits (жизненныйцикл), (простейшееживотное) generallypassesthrough (несколькостадий) thatdifferinstructureandactivity. 5. (Всепростейшиеживотные) digest their food in (желудко-подобный) compartmentscalled (вакуоли).
Exercise 4. a) Make up collocations using words from both columns.
| intracellular | fluids |
| metabolic | membrane |
| body | biodiversity |
| protective | causes |
| protozoan | organelles |
| major | activities |
b) Fill in the gaps with the collocations from above.
1.Protozoa are microscopic unicellular eukaryotes that have a complex internal structure and carry out complex ….
2. Unlike the relatively simple bacteria, protozoa can have many different … performing specific tasks.
3. Parasitic protozoa get their nutrients from the … of their hosts.
4. Cysts are stages with a … or thickened wall.
5.… includes some 32,000 living species and another 34,000 extinct species.
6.Protozoan parasites are … of human and animal diseases.
Exercise 5. Translate from Russian into English.
1. Простейшие – это микроскопические одноклеточные эукариоты, которые имеют сложную внутреннюю структуру. 2. Некоторые виды простейших имеют структуры, которые аналогичны рту, пищеварительному тракту и анусу. 3. На основе типа питания простейшие могут быть классифицированы на: а) свободно живущих, которые питаются бактериями, дрожжами и водорослями и б) паразитических простейших, которые получают свои питательные вещества из жидкостей тканей своих хозяев. 4. В течение своего жизненного цикла простейшее животное проходит через несколько стадий, которые различаются по структуре и деятельности. 5. Четыре основные группы простейших выделяются на основе их движения: амебы, жгутиковые, реснитчатые и споровики.
Exercise 6. The answers to the following questions are the summary of text. Answer these questions and give the summary of the text.
1. What are protozoa?
2. What do you know about their structure and metabolic activities?
3. Why are they named so?
4. How can protozoa be classifiedtaking into account type of their nutrition?
5. What are the main stages in protozoan life cycle?
6. How do cysts help the parasite to survive in the outside environment for a long time?
7. What are the main groups of protozoa that arerecognized on the basis of their locomotion?
8. What do you know about protozoan biodiversity?
Exercise 7. Find more on protozoa at:
https://www.sciencedaily.com/terms/protozoa.htm;
https://en.wikipedia.org/wiki/Protozoa;
http://www.microbeworld.org/types-of-microbes/protista/protozoa;
Make a report in writing (1 page) on the topic “Protozoa and their diversity”.
TEXT B
COCCIDIOSIS IN CATTLE
VOCABULARY LIST TO TEXT B
| coccidiosisn | [kɒkˌsɪdiːˈəʊsɪs] | кокцидиоз |
| coccidiostatn | [kɒkˈsɪdiːəʊˌstæt] | кокцидиостат |
| confined adj | [kənˈfaɪnd ] | стесненный |
| damagev | [ˈdæmɪdʒ ] | разрушение |
| densityn | [ˈden.sɪ.ti ] | плотность |
| dehydrationn | [ˌdiː.haiˈdrei.ʃən ] | обезвоживание |
| distinctiveadj | [dɪˈstɪŋk.tɪv ] | отчетливый |
| electrolyten | [ɪˈlek.trə.laɪt ] | электролит |
| fecesn | [ˈfiː.siːz ] | фекалии |
| genussg(generapl)n | [ˈdʒɪ:nǝs] [ˈdʒen.ər.ə] | род, вид |
| hatch v | [hætʃ ] | вылупляться |
| hygienen | [ˈhaɪ.dʒiːn] | гигиена |
| impact n | [ˈɪmpækt ] | воздействие |
| impairedadj | [ɪmˈpeəd] | ослабленный |
| lining n | [ˈlaɪ.nɪŋ ] | выстилка |
| measure n | [ˈmeʒər ] | мера |
| mucus n | [ˈmjuː.kəs ] | слизь |
| multiplyv | [ˈmʌltɪplaɪ ] | размножаться |
| moisture n | [ˈmɔɪs.tʃər ] | влажность |
| oocyst n | [ˈəʊəˌsist] | ооциста |
| performance n | [pəˈfɔːməns ] | производительность |
| predominantlyadv | [prɪˈdɒm.ɪ.nənt.li ] | преимущественно |
| premises n | [ˈpremɪsɪz] | помещение |
| preventive adj | [prɪˈven.tɪv ] | профилактический |
| range v | [reɪndʒ ] | варьироваться |
| rupture v | [ˈrʌp.tʃər ] | разрываться |
| severity n | [sɪˈver.ɪ.ti ] | тяжесть |
| shedv | [ʃed ] | выделять (организм) |
| sporulatev | [sporjʊˈleɪt] | спорулировать |
| stainedadj | [steɪnd ] | испачканный |
Coccidiosis in cattle is an acute destruction of intestinal mucosa by protozoa of the genera Eimeria.Itis seen universally, most commonly in young animals housed in small areas. The disease is characterized by high morbidity, with moderate deaths and impairedperformance of calves that recover. Coccidiosisis one of the most economically important cattle diseases in the industryand can be a major problem on individual dairyfarms.Economic losses result from poor growth rates, occasional deaths and treatment costs.
Coccidiosis is transmitted from animal to animal by the fecal-oral route. Coccidiaoocysts are shed in the feces of both affected animals showing symptoms and carrier animals not showing symptoms. With the right environmental conditions (moisture and temperature) the oocytes sporulate(hatch and divide) and become infective. Infected fecal material can contaminate feed, water or soil; therefore, cattle can contract the disease by eating and drinking from contaminated sources, or by licking itself or other animals.Calves may become infected bydrinking milk from infected mothers.
If ingested, the parasites can develop inside the host animal, causing damage to intestinal cells and potentially resulting in the host animal having diarrhea and blood in the feces. Damage to the intestinal mucosa also impacts the animal’s ability to absorb fluids to compensate for the water losses in the diarrhea. Parasites invade the cells of the lining of the small intestine where they grow and multiply. The intestinal cells hosting these parasites rupture causing damage to the intestinal lining. The parasites then invade the large intestine cells where they reproduce causing damage and eventually forming oocytes, which are passed in the feces.Disease occurs when large numbers of the infective form of the protozoa (oocysts) are ingestedor whenthe animal’s resistance is lowered by stress, poor nutrition or other disease.
Coccidiosis usually occurs in calves between 3 and 8 months of age, but can occur in calves as young as 4 weeks old.Older cattle are less susceptible to disease than younger cattle unless they are experiencing extreme stress or have depressed immune systems. The disease occurs commonly in confined conditions.
Clinical signs range from mild to severe and include diarrhea, with a distinctive circular pattern of feces around the tail. It is often blood-stained with mucus. Sick animals usually have decreased appetiteand mild depression. In serious cases, this may progress to severe depression, dehydration, pale mucous membranes,big weight loss and emaciation. The severity of the disease depends on the number of oocysts ingested. The more oocysts ingested, the more severe the disease.Some cattle with coccidiosis may have neurologic symptoms (muscular tremor, convulsions of head and neck).Nervous signs and a high mortality rate (80%–90%) are seen in some calves with acute clinical coccidiosis.Death is predominantly a result of electrolyte loss and dehydration caused by the diarrhea. Death may occur during the acute period, or later from secondary complications, such as pneumonia. Coccidiosis is diagnosed by clinical signs, fecal examination, and by postmortem examination.
To achieve effective control of coccidiosis, good management and hygiene are needed. These include reducing stock density, preventing fecal contamination of feed and water, cleaning and disinfecting buildings with steam or water spraying with a product that kills oocysts. Infected calves should be separated from the rest of the herd. The purpose of preventive measures is not only to prevent disease in animals, but also to decrease the concentration of parasites on the premises. There is novaccineagainst coccidiosis; prevention or treatment consists of traditional products that kill coccidia.Preventive drugs are calledcoccidiostats because they stop multiplication of coccidia.
EXERCISES TO THE TEXT
Exercise 8.Look through the text and find information about:
- protozoan species causing coccidiosis;
- economic importance of coccidiosis;
- coccidiosis morbidity rate;
- ways of coccidiosis transmission;
- clinical signs of coccidiosis;
- nervous signs of coccidiosis and when they are observed;
- treatment and prevention of coccidiosis.