Protozoan and Helminth Infections of Aviary-Reared Alectoris rufa (Galliformes: Phasianidae) before Releasing for Hunting in the Czech Republic: Infection Dynamics and Potential Risks.

Age-related dynamics of protozoan and helminth infections in the red-legged partridge, Alectoris rufa, were studied in an intensive breeding aviary in the Czech Republic before releasing birds for hunting purposes. Pooled fecal samples (n = 900) were examined over 3 rearing seasons (2012-2014). A total of 4 protozoan species, Cryptosporidium baileyi, Cryptosporidium meleagridis, Eimeria kofoidi, and Eimeria legionensis, and 4 helminths, Capillaria phasianina, Eucoleus perforans, Heterakis gallinarum, and Syngamus trachea, was found. The most common parasite was S. trachea (prevalence 20-26%) in dead birds (n = 99), which represents a high risk for breeders. Co-occurrence of protozoans and helminths indicated similarities in infection dynamics throughout the 3 breeding seasons. Mixed infections of Cryptosporidium baileyi and C. meleagridis with other parasitic species are reported for the first time. Our findings provide new insights into breeding of A. rufa and may help to improve the efficacy of disease control strategies and prevention, especially with the potential for spreading of parasitic infections to wildlife through released birds into open areas.

Comparison of digestive microflora between feedlot cattle with and without infection by Cryptosporidium andersoni.

The influence of cryptosporidial abomasitis on digestive anaerobic microflora in feedlot cattle with spontaneous Cryptosporidium andersoni colonization of abomasum was shown. Significant differences were found after the cultivation of abomasal content. Scopulariopsis brevicaulis was detected in damaged areas of infected abomasum. PCR analysis of ruminal fluid showed no differences between the two animal groups regarding qualitative composition of anaerobic and facultative anaerobic rumen microflora. The concentration of volatile fatty acids (acetate, propionate, butyrate) and ammonia in the rumen content showed that examined metabolic parameters were within normal limits except for ammonia content, which was higher in infected (291 mg/kg) than in healthy animals (203 mg/kg).

A redescription of Cryptosporidium galli Pavlasek, 1999 (Apicomplexa: Cryptosporidiidae) from birds.

Cryptosporidium galli Pavlasek, 1999, described from the feces of birds, is redescribed with additional molecular and biological data. Oocysts are ellipsoidal, are passed fully sporulated, lack sporocysts, and measure 8.25 x 6.3 microm (range 8.0-8.5 x 6.2-6.4 microm) with a length-width ratio of 1.30 (n = 50). Oocysts are structurally similar to those of Cryptosporidium baileyi described from chickens, but in addition to being considerably larger than oocysts of C. baileyi, these oocysts infect the proventriculus in a variety of birds and not the respiratory tract. Oocysts were successfully transmitted from chickens to chickens, and morphologically similar oocysts also were observed in a variety of exotic and wild birds (Order Passeriformes, Phasianidae, Fringillidae, and Icteridae). Molecular and phylogenetic analyses at the 18S rRNA, HSP70, and actin gene loci demonstrate that this species is genetically distinct from all known species and genotypes of Cryptosporidium and, thus, was named C. galli.

Performance and oocyst shedding in broiler chickens orally infected with Cryptosporidium baileyi and Cryptosporidium meleagridis.

To study effects of experimental cryptosporidiosis, broiler chickens were infected per os with 5 x 10(5) oocysts of Cryptosporidium baileyi and Cryptosporidium meleagridis. In the first experiment, chickens were infected with oocysts of C. baileyi at the age of 7, 14, and 21 days. In the second experiment, chickens were infected with oocysts of C. baileyi, C. meleagridis, or both cryptosporidial species at the age of 7 days. Although clinical signs of infection were apparent, neither final live weight nor mortality was significanty influenced in chickens infected with a single Cryptosporidium species. In chickens infected with C. meleagridis, the growth retardation was observed in the 2-wk period after infection. The compensatory growth, however, started when the oocyst shedding had ceased. The number of oocysts in excreta specimens of chickens infected with C. meleagridis was two to three times lower than in excreta of chickens infected with C. baileyi. Chickens infected with both C. baileyi and C. meleagridis (5 x 10(5) oocysts of each) had significantly lower final live weight and worse feed efficiency than chickens of other groups. Concurrent infection did not influence individual C. baileyi or C. meleagridis oocyst shedding.

Susceptibility of common voles to experimental toxoplasmosis.

Common voles (Microtus arvalis) in groups of nine to 10 animals were inoculated per os with a dose of 1, 10, 1x10(2), 1x10(3), and of the K1 strain of Toxoplasma gondii. All the common voles inoculated with 1 to 1 x 10(3) oocysts remained subclinical and survived. Three of the 10 voles inoculated with 1 x 10(4) oocysts died between days 7 and 12 post inoculation (p.i.). Antibodies were demonstrated in all the infected voles killed on day 60 p.i. The highest antibody titres in voles detected by the dye test (DT) and latex agglutination test (LAT) were 1,024 and 1,280, respectively.

Molecular and phylogenetic analysis of Cryptosporidium muris from various hosts.

Isolates of Cryptosporidium muris and C. serpentis were characterized from different hosts using nucleotide sequence analysis of the rDNA 18S and ITS1 regions, and the heat-shock (HSP-70) gene. Phylogenetic analysis confirmed preliminary evidence that C. muris is not a uniform species. Two distinct genotypes were identified within C. muris; (1) C. muris genotype A; comprising bovine and camel isolates of C. muris from different geographical locations, and (2) C. muris genotype B comprising C. muris isolates from mice, a hamster, a rock hyrax and a camel from the same enclosure. These 2 genotypes may represent separate species but further biological and molecular studies are required for confirmation.

Experimental toxoplasmosis in house sparrows (Passer domesticus).

A total of 31 house sparrows (Passer domesticus) were divided into five groups of six to seven birds. Birds were infected per os with 1, 10, 102, 103 and 104 oocysts of Toxoplasma gondii of the K1 strain, respectively. When the general health, production of antibodies against T. gondii and isolation positivity of the sparrows were examined in weeks 3, 7 and 12 post-infection (p.i.), no clinical signs of toxoplasmosis were observed. Seroprevalences ascertained in weeks 3, 7, and 12 p.i. were 64% (18 positive/28 tested), 95% (21/22) and 70% (7/10) when tested by indirect immunofluorescence (titre 20); 54% (15/28), 59% (13/22) and 70% (7/10) when tested by the latex agglutination test (titre 20); and 59% (4/7), 0% (0/12) and 20% (2/10) when tested by the Sabin Feldman dye test (titre 4), respectively. T. gondii was re-isolated from 45% (13/29) infected sparrows. House sparrows were found to exhibit some resistance to the K1 strain of T. gondii after oocyst infection, and the results suggest that sparrows may not be a significant source of environmental infection.

[Occurrence of Echinococcus multilocularis Leuckart, 1863, in foxes (Vulpes vulpes) in the Czech Republic]. / Výskyt Echinococcus multilocularis Leuckart, 1863 u lisek (Vulpes vulpes) v Ceské republice.

During the period between December 1994 and December 1996 the authors examined, using the method of helminthological dissection of the intestinal tract in 15 districts of four regions in the Czech Republic a total of 824 foxes from 350 land registers. Echinococcus multilocularis was found in the following regions: South Bohemian (districts Jindrichuv Hradec, Ceský Krumlov, Prachatice and Strakonice), Central Bohemian (Benesov district) and North Bohemian (district Teplice and Chomutov). There were 87 positive (10.6%) foxes in 56 places (16%). In some areas of the South Bohemian region examinations of foxes were repeated. It was found that there are places where the prevalence of E. multilocularis varied between 28.6 and 75% (mean 53.7%) but also areas which were repeatedly negative. In 1996 after one-week intervals foxes from the Prachatice district (South Bohemian region) were sent for parasitological examination. During different months of the year the prevalence of E. multilocularis varied between 2.6 and 33.3%. A similar investigation was made during May to October 1996 (except September) also in the district of Ceský Krumlov (South Bohemian region). Tapeworms were found in 7.14 to 66.7% of foxes.

[Spontaneous Cryptosporidium infection in weaned rabbits]. / Spontánní kryptosporidiová nákaza u odstavených králícat.

The first occurrence of Cryptosporidium parvum Tyzzer, 1912 in broiler rabbits in the Czech Republic is reported. The protozoon was determined on the basis of morphometrical parameters of oocysts and of localization of endogenous developmental stages. The dynamics of natural Cryptosporidium infection was studied in a group of 72 young rabbits after weaning (their age ranging from 23-33 to 82-92 days) obtained from six large flocks and used in a feeding experiment. C. parvum was found in rabbits from four farms (Tab. I). Animals under observation were divided into 9 subgroups according to the genotype (Hyla 2000, California White, crosses of New Zealand x California, New Zealand White, Cunistar and Zika) as well as according to the farm of origin. The animals were housed in 28 cages under the conditions of two-floor cage technology. The upper floor consisted of cages housing three head, the lower floor two head each. The animals were fed ad libitum with commercial feed mixture (till the average age of 64.days supplemented with Robenidin as coccidiostat). During the first 10 days of observation pooled samples of droppings from each cage were examinated by flotation-centrifugation method according to Breza (1957) and Pavlásek (1991) in the intervals of three to four days, later one-week intervals. Post mortem scrapings from mucous epithelium taken from young rabbits were examinated (to reveal endogenous developmental stages of C. parvum) together with digesta (to detect oocysts of the protozoon) taken from the full length of the small intestine using method of native preparations and Giemsa stain. In one 37-day dead animal the small and large intestines were examined histologically. The maximum number of young rabbits infected with C. parvum were 30-40 and 33-43 days old (Fig. 1). In animals of this age category the oocysts of the protozoon were found in pooled samples in 11 and 12 cages (39.3 and 42.9%) from totally 28 cages under study. In rabbits of more than 50 days of age the occurrence of infection was significantly decreased (3.7%). During the experiment seven rabbits (9.7%) died; six of them (8.3%) at the age of 30-40 days. All these naturally infected and dead animals represented cases of monoinfection with C. parvum. The major clinical signs were typical diarrhoea lasting 3-5 days, inappetency, apathia, lethargy, prominent signs of exhaustion followed by dehydration of the organism. Atrophy of villi of the ileum in one of young rabbits was found histologically. Table II presents concrete data on significantly lower body weights (the decrease being 7-61.5%) as compared with rabbits of the same age not infected with cryptosporidia. It was not possible to evaluate objectively the differences in susceptibility to C. parvum infection between the individual genotypes of rabbits. As was found in the course of our further studies (unpublished data) a possible source of infection of young rabbits can be represented by their mothers in which oocysts are excreted sporadically shortly before parturition and during several days after it. Cryptosporidium infection (cryptosporidiosis) in flocks of broiler rabbits is taken as a new protozoal disease in the Czech Republic and C. parvum as one of possible agents in cases of disorders of digestive tract, namely in rabbits after weaning.

[Cryptosporidia and other endoparasites in heifers imported into the Czech Republic]. / Nálezy kryptosporidií a dalsích endoparazitu u jalovic dovázených do Ceské Republiky.

Totally 887 heifers of Holstein-Friesian breed mostly in late pregnancy imported to the Czech Republic from France (597), Germany (89), Denmark (181) and Holland (20) were examined coprologically from September 1993 to March 1995 in the parasitological laboratory of the National Veterinary Institute (NVI). Prague. Feces were sampled individually, rectally, always on days 1-3 following importation from heifers housed in particular quarantine sheds. In compliance with presently valid veterinary regulations, all animals were examined for liver fluke disease (fascioliasis) and lungworm. Moreover, 634 heifers were submitted to qualitative coprological examination aimed at revealing the presence of cysts and oocysts of protozoa, eggs of taenias and nematodes of gastrointestinal tract. The method according to Pavlásek (1991), especially designed for proving oocysts of the genus Cryptosporidium, was applied in all fecal specimens delivered to the SVI from animals in quarantine (N = 887). From trematodes, 12 heifers imported from France were positive for eggs of Fasciola hepatica and in other two animals eggs of the genus Paramphistomum were found. None of the imported heifers showed lungworm disease. Summary of data on occurrence of endoparasites gained during qualitative examination of samples of feces taken from heifers imported from France, Germany and Denmark is presented in Tab. I. Parasitologically, 91.2 to 100% of imported animals were positive. Taeniasis (the genus Moniezia) was detected in 2.8% of heifers imported from France and in 9.8% animals from Denmark. Protozoal parasites were found in 58.8% (Denmark) and 92.8% (Germany) heifers. Coccidial oocysts most frequently observed represented the genus Eimeria (E. bovis, E. auburnensis and E. zuernii). Gastrointestinal nematodes of nine genera were found in 72.5 to 80.8% of heifers. The most frequent findings were genera Ostertagia, Haemonchus and Trichostrongylus. Oocysts, morphologically identical with Cryptosporidium muris Tyzzer (1907), 1910, were detected in 4.5% of heifers imported into the Czech Republic from France and in 7.9% of those from Germany. In view of the fact the imported heifers were sampled always on days 1-3 of their quarantine following their importation it is quite impossible, considering the development of the protozoon, they could become infected just in the territory of the Czech Republic. Therefore, with the highest probability, our findings of C. muris-like oocysts in heifers are of priority importance for France and Germany because in the literature these countries do not report cattle as a host of this protozoon. We have found out 57.9% out of 19 animals positive for C. muris on one farm of a private cattle keeper. On the basis of a long-term monitoring of three dairy cows and one bull, the duration of the patent period is longer than 18 months, while we do not know precise onset of shedding oocysts of the protozoon in these naturally infected animals. Furthermore, the paper discusses the need of future studies of C. muris from the point of view of spread, pathogenicity, specificity and host spectrum. The author proposes and recommends obligatory examinations of imported animals with special attention paid to presence of coccidia of the genus Cryptosporidium in order to maintain, with respect to their zoonotic character, these protozoal infections under proper control. At present the parasitological laboratory of the NVI in Prague has a bank of oocyst isolates of the C. muris type from cattle (Bos taurus), from desert hamsters (Phodopus roborovskii Satunin, 1903) and camels (Camelus bactrianus). Experimental infections is permanently kept in laboratory mice following successful transmission from desert hamsters.

[The first finding of a spontaneous gastric cryptosporidiosis infection in hamsters (Phodopus roborovskii Satunin, 1903)]. / První nálezy spontánní zaludecní kryptosporidiové infekce u krecíku (Phodopus roborovskii Satunin, 1903).

The desert hamster (Phodopus roborovskii Satunin, 1903) represents a new host of Cryptosporidium muris Tyzzer (1907), 1910. This very first finding was made in the laboratories of the National Veterinary Institute, Prague, Czech Republic. In September 1994 three 11-month and one 3-month desert hamsters were sent for laboratory examination. Parasitological examination post mortem of a 3-month desert hamster revealed "large" Cryptosporidium oocysts in excrements as well as in the contents of intestines. In all animals in which autopsy was carried out congestion of lungs, spleen and liver, acute catarrhal inflammation and flatulences in portions of gut were observed. Presence of morphologically identical oocysts of cryptosporidia was confirmed in the same group of desert hamsters also during parasitological reexamination carried out in October 1994. Applying the methods according to Breza (1957) and Pavlásek (1991) oocysts of the protozoon under study were detected in pooled samples of excrements of 3, 4, 5, 10 and 11-month animals. Two out of four live 2-3-month desert hamsters were infected naturally, both parents (10-11 months old), sent by the owner to our laboratory to be used for further observation. Both adult animals showed slight tremor, somnolence, rough hair and recumbent position, the male showed paresis of pelvic limbs. For four days in the laboratory conditions excrements of all six live desert hamsters, the interval being 2-12 hours, were examined and in four of them the finding of oocysts of the protozoon was repeatedly positive. Adult animals were euthanasied.(ABSTRACT TRUNCATED AT 250 WORDS)

[The fist detection of Giardia spp. in horses in the Czech Republic]. / První nálezy Giardia spp. u koní v Ceské republice.

The first occurrence of Giardia spp. in horses in the Czech Republic is reported. During preventive examination of 360 five-month up to 14-year horses from various parts of the region of Central Bohemia carried out from January 1993 to June 1994 in the parasitological laboratory of the State Veterinary Institute in Prague, the Giardia cysts were detected in the excrements of 18 (5%) horses, mostly 2-4 years of age, and in two foals 3 and 6 weeks old. During the period between March 1993 and June 1994, systematic and repeated observation was aimed at a group of 38 racing horses two up to four years of age from two studs in the surroundings of Prague. In one of these studs Giardia spp. cysts were found in 7 horses (35%) out of a total of 20 animals. During bacteriological examination of horses infected with Giardia carried out parallely, only in one animal pathogenic bacteria Rhodococcus equi and Streptococcus equi subsp. zooepidemicus were detected in the excrements. After the application of Entizole (following discontinuation of the preparation on days 4 and 50), however, the result of bacteriological examination was negative. The size of cysts (n = 100) was 12.8-16.0 x 9.6-11.2 microns (with the mean of 14.6 x 9.9 microns) there was no finding of free trophozoites of Giardia in the horse excrements examined. On the basis of morphological characteristics of the protozoon cysts and of the structure of median bodies (following excystation of the Giardia cysts in vitro), the intestinal flagellate found in horses can be included into the morphological group of G. intestinalis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Localization of endogenous developmental stages of Cryptosporidium meleagridis Slavin, 1955 (Apicomplexa: Cryptosporidiidae) in birds]. / Lokalizace endogenních vývojových stadií Cryptosporidium meleagridis Slavin, 1955 (Apicomplexa: Cryptosporidiidae) u ptáku.

Localization of endogenous developmental stages of C. meleagridis was studied on the basis of observation of 4734 preparations from individual parts (in the distance of approx. 5 cm) of the small intestine, caeca (collum caeci, corpus, apex caeci), colon, cloaca, bursa of Fabricius, respiratory organs (sinus infraorbitalis, larynx, trachea, bronchi, air sacs) using the method of scraping mucous epithelium stained according to Giemsa after fixation with methanol (as well as histologically) from 155 naturally infected 9-66 day turkeys (Meleagris gallopavo f. dom.) in four large flocks in Central Bohemia, ten 46 and 47 day chicks (Gallus gallus f. dom.) and 1-3 day chicks infected experimentally. The protozoon was detected in various stages of its development in the microvilli of the small intestine of chicks 23-39 days old in the portion of 40-80 cm from the end of the duodenum. On day 5 after infection, asexual stages were found in experimentally infected chickens as near as in 8-12 cm. All forms of endogenous developmental stages including oocysts occurred usually massively in approx. 10 cm from the site of bifurcation of the caeca (plica ileocaecalis) in the ileum and in the collum caeci. The infection was prominently less intensive in the case of mucous epithelium of the colon, in the cloaca only meronts occurred very sporadically showing various developmental stages. The findings in the bursa of Fabricius and in the organs of respiratory tract were negative. In a total of 129 turkeys examined post mortem on three farms C. meleagridis were observed, endogenous developmental stages of the protozoon were found in 55 (42.6%) cases. Asexual stages (meronts in different stages of development) were observed sporadically for the first time in 23 days old birds. Maximum of infected turkeys in which all developmental stages of C. meleagridis were localized above all in the ileum and collum caeci were 30-39 days old (out of the total number of 60 dead birds examined the infection occurred in 30, i.e. in 63.3%). C. meleagridis was found in nine out of 10 dead 46- and 47-day chicks on two farms and in five out of 98 dead 14-49 day chicks, in four out of 10 pullets 7-9 months old and in one out of 22 dead parrots (Cacatua molucensis) sent for routine examination to the State Veterinary Institute in Prague from different parts of Central Bohemia.(ABSTRACT TRUNCATED AT 400 WORDS)

[The black-headed gull (Larus ridibundus L.), a new host for Cryptosporidium baileyi (Apicomplexa: Cryptosporidiidae)]. / Racek chechtavý (Larus ridibundus L.), nový hostitel Cryptosporidium baileyi (Apicomplexa: Cryptosporidiidae).

Black-headed full (L. ridibundus L.) represents a new host of C. baileyi Current, Upton and Haynes, 1986. In 1991-1992 during the months of May-July six localities in three regions of the Czech Republic were studied by examining in total 264 not flying gull chicks (4-30 days of age), applying the methods after Pavlásek (1987a, b, 1991). Cryptosporidia were found in gulls in all localities and spontaneous infection during the period under study occurred in 27.5-100% of birds (Tab. II, Fig. 1). The size of oocysts was 6.2-6.4 by 4.8-5.8 microns with means of 6.4 by 4.9 microns. The oocyst index (width/length) was 0.75-0.93 with means of 0.77. C. baileyi infection was demonstrated in 22 out of 24 dead gull chicks submitted to autopsy. From two localities total 15 gulls were killed, the examination of which revealed oocyst occurring in masses in the fluid from cloacal washes. Asexual and sexual endogenous developmental stages, including C. baileyi oocysts, in all birds undergoing autopsy were localized in caudal part of colon (1-2 cm from opening into cloaca) and in the cloaca. Findings of cryptosporidia were very frequent, above all, in the bursa Fabricii. In two dead and six with snoring disease, subsequently killed gull chicks, respiratory form of infection was demonstrated with simultaneous proof of endogenous developmental stages including oocysts in smears of mucous epithelium of sinus infraorbitalis, larynx, trachea and bronchi using the Giemsa stain after fixation with absolute methanol. An experimental transmission of infection by isolates of C. baileyi oocysts from gulls to five 4-day chicks (Gallus gallus f. domestica) using the dosis of 5 x 10(5) oocysts/chick was successful. The prepatent period lasted 4 days. On day 3 and 6 after infection two chicks died. The developmental stages of the protozoon were found in the lower part of colon, in cloaca and in bursa Fabricii. In chicks dead on day 6 after infection asexual stages of cryptosporidia were found in trachea and in bronchi. One chick survived the infection and excretion of oocyst (patent period) lasted 14 days. In this bird cloacal, bursal as well as respiratory form of C. baileyi infection was found. Control chicks were negative during the observation of 30 days. Oocysts from gulls do not lose their viability even after 8-month storage in the 2.5% solution of K2Cr2O7 at the temperature of 4 degrees C.(ABSTRACT TRUNCATED AT 400 WORDS)

[The first finding of Giardia spp. in roebucks (Capreolus capreolus L.)]. / První nálezy Giardia spp. u srnce obecného (Capreolus capreolus L.).

Roe deer (Capreolus capreolus L.) is a representative of the new host of an intestinal flagellate of the genus Giardia. Giardia spp. was found during autopsy in three dead head of roe deer (roe deer calf 7-8 months, doe, buck) sent for examination to the State Veterinary Institute, Praha, from three different localities of the Czech Republik. Localization of the Giardia spp. was studied in the intestinal tract of the roe deer calf in native preparations in the intestinal contents and in the smears of intestinal mucosa stained after Giemsa (at a distance of 30-40 cm along the whole length of the small intestine). Giardia trophozoites were found in the small intestine in the section of 280-770 cm from the caudal part of duodenum. The trophozoites occurred most intensively within the section of 350-420 cm. The trophozoites showed active, motility in this part of the small intestine as late as in more than 48 hours after the death of the row calf. Their size (obtained by measuring 30 trophozoites) was from 12.4-16.2 to 8-11.5 microns with the mean of 14.5 to 9.4 microns. In the contents of the caeca and colons of all three animals after death numerous Giardia cysts were found, in the caecum of the roe calf trophozoites were detected rarely. Most of the cysts were of ovoid shape. Their size, by measuring 50 cysts from each of the animals, was from 11.2-14.4 to 8-10.4 microns with the mean of 13.3 x 9.1 microns. Sporadically, nearly spherical cysts occurred (12.8-13.6 to 9.6-10.4 microns).(ABSTRACT TRUNCATED AT 250 WORDS)

[Methods of isolating pure cultures of invasive intestinal helminth larvae of the genus Strongyloides, suborder Strongylata]. / Metodika izolace cistých kultur invazních larev strevních hlístic rodu Strongyloides a podrádu Strongylata.

A special diagnostic laboratory aid L-STAR has been made and new methodics has been worked out of isolating pure cultures of invader larvae of Strongyloides papillosus and nematodes of ruminant gastrointestinal tract of the Strongylata suborder from various substrates. L-STAR competes successfully with a currently used device and with potential modifications of Baermann's method (1917). Invader larvae of strongyloids and strongylata are easy to recover in a short time if L-STAR is used. When the material is treated and examined in veterinary and human parasitological laboratories, or when the material is recovered directly in field conditions (on pastures, in runs, etc.), safe and hygienic conditions are secured with respect to labour safety in an infectious environment. This aid can be used not only for diagnostics, but also for effective isolation of pure cultures of invader larvae for further studies and experimental purposes.

[The most important parasitic intestinal infections in calves and their role in diarrheal diseases]. / Nejdulezitejsí strevní parazitární nákazy telat a jejich role v etiologii prujmových onemocnení.

Various stock breeding herds in the USSR were examined for the presence of endoparasites. Coccidia of Cryptosporidium genus occurred in calves at the age of 3 to 4 days to one month, individually in older calves, too. Coccidia C. parvum infected the animals aged 14-15 days most frequently. Coccidia of Eimeria genus and intestinal round worm Strongyloides papilosus were registered sporadically in calves aged 13-15 days; most frequently they occurred in calves aged 1-2 months and older. Of the total number of the examined calves (aged 20 days), which were infected by Cryptosporidium, 77.7 resp. 89.8% were diarrhoeic. In cases of polyinfections with various species of coccidia of the Eimeria genus and S. papillosus, diarrhoea was recorded in 31.2% of one- to two-month-old calves. In cases of monoinfection with coccidia of the Eimeria genus diarrhoea was recorded in 15.8% of the calves, and in cases of infection with the intestinal worm S. Papillosus in 9.1% of the calves.