Search PubMed⌕ Search

Biomedical subjects

K T Friedhoff

Publications and source records attributed to K T Friedhoff.

At least 37 records · Page 2Linked to original sources
PubMed1987

Transmission of Trypanosoma theileri to cattle by Tabanidae.

Tabanids were collected in an area in northern Germany, where pastured cattle were abundant. Trypanosomatidae were identified in 14% of tabanids examined. Twelve cattle became infected with Trypanosoma theileri after applying usually 2-5 infected tabanids, to the intact oral mucosa. Haematopota pluvialis, Haematopota italica, Hybomitra micans and Tabanus bromius were identified as vectors. Infective stages of Trypanosoma theileri were identified in the gut and in the faeces of tabanids by transmission experiments. The minimum prepatent period was less than 4 days. No apparent signs of disease were observed in the infected cattle.

Animals↗
PubMed1987

Transmission of Megatrypanum trypanosomes to Cervus dama by Tabanidae.

Four fallow deer, Cervus dama, became infected with Trypanosoma (megatrypanum) sp. by oral application of triturated guts from tabanids collected in an area with deer but without any cattle; four control calves remained negative. Upon challenge with triturated guts from tabanids from an area with pastured cattle, the four calves became infected with Trypanosoma (M.) theileri. The prepatent period in deer was five days or less. Haematopota spp. and Tabanus spp. were identified as vectors of the deer trypanosomes. It is concluded that the trypanosomes of C. dama belong to a Megatrypanum species that is not identical with T. theileri.

Animals↗
PubMed1986

Serodiagnosis of experimental and natural Babesia equi and B. caballi infections.

The sensitivity and specificity of the complement fixation (CF) test for the diagnosis of Babesia infections in equines was assessed, using the indirect fluorescent antibody (IFA) test as a reference. Antibodies were first detected between 11 and 20 days post infection (dpi) in the CF test and between 7 and 14 dpi in the IFA test in ponies infected experimentally with B. equi (USDA strain). The CF test became negative in four of five ponies 63-174 dpi although B. equi was demonstrated microscopically in two of these four ponies up to 364 and 455 dpi. The IFA test remained positive up to 476 dpi (end of the examination period). Ponies infected experimentally with B. caballi (USDA strain) showed positive reactions in the CF test at first between 13 and 15 dpi and in the IFA test 10 or 11 dpi. The CF test became negative in two of three ponies 80 and 140 dpi, whereas the IFA test remained positive up to 190 dpi (end of the examination period). Cross-reactions of sera with heterologous antigens occurred at dilutions of 1/5 in the CF test and up to 1/20 in the IFA test. A total of 3944 CF tests was performed on 3765 horses from various European countries during 1980-1984. Sera that gave positive or trace CF reactions were retested in the IFA test. All 123 CF-positive sera were also IFA-positive and 26 of 31 sera (B. equi) and 11 of 32 sera (B. caballi) showing CF trace reactions were positive in the IFA test. Sera of two CF-negative horses were positive in the IFA test (B. equi); one of these horses was also positive upon microscopic examination. In seven of 21 horses repeatedly examined over longer periods the IFA titers (B. equi) persisted for up to 454 days longer than the CF titers. Sera of horses from highly endemic areas gave the following reactions: Sudan, 62 of 91 sera CF- and 86 of 91 IFA-positive; Zaire, 58 of 75 sera CF- and 72 of 75 IFA-positive; Columbia, 51 of 56 sera CF- and 56 of 56 IFA-positive; Brazil, 17 of 25 sera CF- and 21 of 25 IFA-positive. Only B. equi infections were demonstrated in Zaire. The combined use of the CF and IFA tests is recommended for safe identification of equine Babesia infections.

Animals↗
PubMed1985

The detection of IgM and IgG antibodies against Babesia bigemina in bovine sera using semi-defined antigens in enzyme immunoassays.

Soluble extracts prepared from Babesia bigemina merozoites were tested for antigenicity in class-specific enzyme immunoassays currently being evaluated for the differential serodiagnosis of bovine babesiosis. Intact merozoites were harvested from erythrocytes from an experimentally-infected calf by controlled hypotonic lysis and differential ultra-centrifugation. The merozoites were disrupted by ultrasonication and a crude soluble extract obtained by ultracentrifugation. Fractionation of the crude extract on calibrated Sephadex G-200 columns consistently produced 4 fractions with molecular weights of 600, 40, 15 and 5 k (k = 10(3) daltons). Only the 600 and 15 k fractions proved to be antigenic when reacted against bovine immune sera. These fractions were incorporated into IgM- and IgG-specific enzyme immunoassays and used to determine the kinetics of the host-antibody responses to infection. The use of semi-defined antigens allowed assay standardization and good reproducibility of the results. A calf infected with a cryopreserved stabilate of B. bigemina originating from adult Boophilus microplus ticks developed a mild transient fever from 6-4 days post-infection (d.p.i.) and low parasitaemia levels from 7-16 d.p.i. IgG-antibodies first appeared at 7 d.p.i., peaked in intensity at 12 d.p.i. and then persisted at these levels until the end of the test period at 49 d.p.i. IgM-antibodies appeared at 7 d.p.i., peaked in intensity from 12-22 d.p.i., but then declined to low levels by 28 d.p.i. The importance of this transitory IgM-antibody response in the serodiagnosis of acute B. bigemina infections remains to be determined in clinical and field situations.

Animals↗
PubMed1985

[Histomoniasis in pullet stock and its effect on later laying performance].

In a 17 1/2 weeks old pullet stock typhlohepatitis was diagnosed on the occasion of a stock examination by the poultry health service. Liver and gut of randomly selected pullets showed gross and histologic alterations as known in cases of typhlohepatitis in turkeys. Histomonads could be shown using both the PAS-reaction according to McManus and the silverstaining according to Grocott. In the following controls of the herd macroscopic visible alterations of the liver could not be seen, but some of the animals still exhibited gross lesions in the ceca. The course of the development of the herd from point-of-lay to the 9th month of laying period is described.

Animals↗
PubMed1984

The morphology of ovine Trypanosoma melophagium (zoomastigophorea: kinetoplastida).

Morphologic and biometric data on bloodstream stages of Trypanosoma melophagium are presented. An increasing parasitemia with 111 trypomastigote stages of T. melophagium were found in Giemsa-stained thin blood smears taken from a splenectomized, cortisone-treated sheep recently infested with Melophagus ovinus infected with T. melophagium . The arithmetic mean and standard deviation in micron of the distances between posterior end and kinetoplast were 14.7 and 2.9, from the kinetoplastic to the center of the nucleus 5.1 and 1.1, and from there to the anterior end 19.5 and 1.9. The free flagellum measured 6.0 microns +/- 1.6 microns. The median and the range of the central 70% of values (median +/- 35%) of the nuclear index were 1.1 and 0.9-1.2 and of the kinetoplastic index 3.8 and 3.3-4.9. The same data in microns for the maximal width were 3.1 and 2.1-4.6, and for the width at the level of the nucleus 2.9 and 2.2-4.6. The larger and smaller diameters of the nucleus measured 2.6 (2.2-3.7) micron and 1.7 (1.3-1.7) micron, respectively. The corresponding kinetoplast diameters were 1.1 (0.9-1.3) microns and 0.9 (0.6-0.9) micron, respectively.

Animals↗
PubMed1984

Stercorarian trypanosomes from deer (Cervidae) in Germany.

Twenty of 35 roe deer (Capreolus capreolus), eight of 12 red deer (Cervus elaphus), and nine of 21 fallow deer (Cervus dama) but none of four moose (Alces alces) examined from April to November 1983 were infected with trypanosomes. Morphometric data of the bloodstream trypomastigotes from the three deer species differed significantly. This appears to be the first report of stercorarian trypanosomes from Cervidae in the Old World and the first description of representatives of the subgenus Megatrypanum in the three deer species.

Animals↗
PubMed1984

Trypanosomes in Cervidae in Germany.

Trypanosoma cervi Kingston et Morton, 1975 was demonstrated in 2 fallow deer (Dama dama) in 1976, and in 10 roe deer (Capreolus capreolus) and one red deer (Cervus elaphus) in spring 1983. The infected deer originated from the vicinity of Hannover, Germany.

Animals↗
PubMed1983

Ultrastructural study on the development of Babesia equi (Coccidia: Piroplasmia) in the salivary glands of its vector ticks.

The formation of Babesia equi sporozoites in the salivary glands of three tick species (Hyalomma anatolicum anatolicum, H. a. excavatum, Rhipicephalus turanicus) was studied by electron microscopy. The development was identical in all three vectors. On the 8th day post repletionem kinetes of B. equi had invaded alveoli of the nymphal salivary glands and were transformed to sporonts bounded by a single membrane. The sporonts were polymorphous bodies each with a highly lobed nucleus and numerous mitochondria. These stages persisted during ecdysis of the tick nymph to the adult stage. After attachment of these newly molted adults to a new host the formation of sporozoites was completed within five days. The sporonts occupied most of the infected alveolus and were extensively divided into cytoplasmic portions of various size. On the 4th day after attachment of the tick, sporozoite-anlagen, into each of which a nucleus and a mitochondrion were incorporated, appeared at the periphery of the sporonts. An apical complex with a polar ring, rhoptries, and micronemes was formed at the tip of each protruding anlage. Finally thousands of pyriform sporozoites (3.0 X 1.2 microns) filled the hypertrophied alveolus. This development is similar to sporogony in the genus Theileria.

Animals↗
PubMed1982

Ultrastructural study of the development of Babesia ovis (Piroplasmia) in the ovary of the vector tick Rhipicephalus bursa.

The reproduction of Babesia ovis inside the ovary of the vector tick Rhipicephalus bursa was studied by electron microscopy. The kinetics of B. ovis invade the ovary of the tick via hemolymph. The kinete, when situated intracellularly, is transformed into a polymorphous stage that loses all features of the invasive form. The nucleus elongates enormously and forms many folds which extend throughout the cell. Subsequently, the lobulated nucleus and the cytoplasm are divided into numerous uninuclear cytomeres by invaginations of the cell boundary and by interconnecting endoplasmic reticulum. Each cytomere, bounded by a unit-membrane, measures ca. 4 microns in diameter and finally forms a new kinete. This proceeds as protrusion of the cytoplasm into an intracytoplasmic vacuole. An apical complex is initially visible at the tip of the protrusion that emerges steadily into the lumen of the expanding vacuole. The nucleus of each cytomere is incorporated into the newly formed kinete, which is surrounded by a coccidian pellicle the inner membranes of which are formed at the base of the intracellular protrusion. Nearly all of the cytoplasm is used for the differentiation of the kinete, which finally lies folded inside the vacuole. The kinete is apparently released by rupture of the vacuole. The description of this peculiar reproduction completes the knowledge of similar reproductive processes in other tissues of the tick. A comparison of the differentiation of the kinete in Babesia and in Theileria indicates a similar mode of development.

Animals↗
PubMed1982

Electron microscopic study on the development of Babesia ovis (Piroplasmia) in the salivary glands of the vector tick Rhipicephalus bursa.

The formation of Babesia ovis sporozoites in salivary gland cells of the vector tick Rhipicephalus bursa was studied by electron microscopy. The kinetics of B. ovis were found lying intracellularly on the second day after infestation (a.i.) of the ticks. The parasites enlarged rapidly losing all features of the motile form. Invaginations of the cell membrane initiated a fragmentation of this developmental stage. On the third day a.i the parasite (measuring 40 x 25 microns) was divided into numerous single membrane-bounded cytomeres, each provided with at least one lobed nucleus. On the fourth day a.i. sporozoite differentiation started at the periphery of the cytomeres, indicated by the appearance of several pellicle-bounded, exogenous protrusions into each of which a small portion of the nucleus was incorporated. Since the cytomeres lay very close together this differentiation occurred more by segmentation than by budding. Rhoptries and the so-called spherical body appeared in this developmental phase. Finally, the isolated, immature sporozoites lay in a granular matrix which contained remnants of the host cell cytoplasm. On the fifth day a.i. the sporozoites were fully developed, typically pear-shaped (2.8 x 1.2 microns) and provided with all characteristic structures of the invasive form.--This reproduction was compared to similar processes in other species of the Piroplasmia and the Haemosporina.

Animals↗
PubMed1980

Fine structure of trophozoites and cysts of the pathogenic diplomonad Spironucleus muris.

Using light and electron microscopy, we studied the ultrastructure of Spironucleus muris (syn. Hexamita muris) from spontaneously and experimentally infected normal and athymic mice. Kinetosomes and cytoskeletal fibers arranged in two-fold rotational symmetry are similar to the species Spironucleus elegans from amphibians. Taxonomic proposals and a possible evolutionary scheme for diplomonad genera accepted at the last International Congress of Parasitology are given. The genus Hexamita should be divided into two new genera: Hexamita (usually free-living) and Spironucleus (exclusively parasitic). We consider previous descriptions of hexamitiasis in rodents as dealing with spironucleosis. We distinguish a fresh and an old cyst of the parasite on the basis of structure, light refraction, location in the host, and infectivity. The transition from a fresh to an old cyst parallels the dessication of feces. The trophozoites can damage the microvilli and penetrate into the epithelium. We explain the differences in findings concerning intestinal lesions and forms of the disease (from acute to chronic to latent) by differences in the virulence of different parasite strains and by differences in inherent host resistance.

Animals↗
PubMed1978

[Light microscopic studies on the development of Theileria annulata (Dschunkowsky and Luhs, 1904) in Hyalomma anatolicum excavatum (Koch, 1844). II. The development in haemolymph and salivary glands (author's transl)].

Fully differentiated kinetes, average length 17.6 micrometer, appeared in the haemolymph of engorged nymphs usually 17 to 20 days after repletion. Kinetes were observed at first in the salivary glands on day 18 after repletion. The kinetes then transformed into fission bodies of about 10 micrometer in diameter, mainly in type III alveoli and less frequently in type II alveoli. The fission bodies grew up to a size of about 20 micrometer after several divisions of their nucleus. At this time the ticks moulted and no further development occurred until activation. Shortly before infestation the salivary glands began to proliferate, and rapid growth of the fission bodies was observed, especially in young ticks where development of 'infective particles' ('sporozoites') was concluded within two days. Development in feeding adult ticks apparently occurred in four major steps: (1) Division of primary fission bodies (sporonts) into numerous secondary fission bodies ('primary sporoblasts'), (2) division of secondary fission bodies into tertiary fission bodies ('secondary sporoblasts'), (3) production of particles ('sporozoites') by tertiary fission bodies and release of particles into the saliva, and (4) degeneration of fission bodies and their host cell but further release of particles. The host cell was stimulated to giant growth, thus its diameter increased, on average, from 15 to 110 micrometer. Heavy infections resulting from parasitaemias of greater than 40% caused disease and mortality in the tick population. Development was much retarded by aging. In ticks starved for six months 'sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' did not develop before day five to seven of infestation. 'Sporozoites' may not develop at all in six to nine month old female ticks during the infestation period. The significance of the described developmental stages of T. annulata was discussed and a sexual generation postualted. The hypothetic development of T. annulata in its tick vector was illustrated.

Animals↗