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192 records · Page 11Linked to original sources
PubMed1985

[Preliminary studies on the occurrence of Rickettsiae of the spotted fever group in Rhipicephalus sanguineus captured in suburban areas].

In the urban periphery of Rome, two sub-zones could be distinguished, characterized by uncultivated steppeland and by small shacks with large quantities of domestic refuse, respectively. Rhipicephalus sanguineus appeared to be typical of this second sub-zone. R. sanguineus adults and nymphae were captured in different seasonal periods and were checked for the prevalence of rickettsiae of the Spotted Fever (SF) group. Moreover, larvae from hatched eggs, laid by captured R. sanguineus females, were checked for the transovarial transmission of rickettsiae. Ten lots each of three guinea-pigs, seronegative to rickettsiae of the SF group, were inoculated with R. sanguineus extracts, prepared from adults or larvae. Clinical signs of infection, fever and scrotal reaction, could be observed only in one lot of guinea-pigs inoculated with adult parasites. On the other hand, in 8 out of 10 guinea pig lots, antibodies to the soluble antigens of R. conori and R. slovaca were observed by the complement fixation (CF) test. In the remaining two lots only antibodies to R. slovaca were detected. No antibodies to Coxiella burneti could be demonstrated in the same sera.

Animals↗
PubMed1974

Plaque assay of rickettsiae in a mammalian cell line.

Clear-cut and repeatable plaque assays were obtained for three rickettsiae of the spotted fever group (Rickettsia rickettsi, R. conori, and R. montana) in Vero cells used in a manner similar to that for arboviruses. In addition, three typhus group agents (R. typhi, R. canada, R. prowazeki) induced plaques in these cells. In preliminary tests Coxiella burneti (Nine Mile strain) failed to produce plaques. Comparable results were obtained in plastic flasks and plastic culture trays incubated in ambient air with or without addition of N-2-hydroxyethyl-piperazine-N'-2-ethanesulfinic acid buffer. Larger and more well defined R. rickettsi plaques were produced when cultures were overlaid with Leibovitz (L15) medium than with either medium 199 or Eagle medium. Phosphate-buffered saline containing bovine plasma albumin (fraction V), in contrast to brain heart infusion broth, as a diluent for preparing inocula consistently permitted development of larger and more numerous plaques with three agents: R. rickettsi, R. conori, and R. montana. When R. rickettsi and R. typhi were assayed in parallel in primary chicken embryo cultures and Vero cells, comparable results were obtained, but with R. canada results in Vero cells were superior. In contrast, R. prowazeki produced inconsistent results in Vero cells.

Animals↗
PubMed1979

Chronic cryptic Q-fever infection of the heart.

Evidence of chronic Coxiella burneti infection of the heart, a disease previously considered peculiar to patients with valvular heart-disease, was found in a patient during routine serological tests before resection of a ventricular aneurysm and also by isolation of the rickettsia from the resected tissue. The patient had no symptoms or signs of Q-fever endocarditis and none of the laboratory evidence usually associated with it.

Antibodies, Bacterial↗
PubMed1966

Evidence of rickettsial disease agents in ticks from Ethiopian cattle.

Evidence has recently been accumulating that domestic animals may play an ancillary role in rickettsial zoonoses. In particular, attention has been focused on the activity of Rickettsia prowazekii in Egyptian and Ethiopian livestock and their ticks. An attempt has now been made to confirm previous findings of R. prowazekii in the sera of zebus, sheep and goats in Ethiopia, which brought epidemic typhus into the category of a zoonosis. This attempt was not successful, but tests did indicate that some ticks were infected with R. conori (boutonneuse fever or tick-borne typhus) and Coxiella burneti (Q fever), this being the first evidence for the existence of these agents in Ethiopia.Antibodies against R. conori were found in significant numbers in the sera of sheep and goats from one locality, but Q-fever antibodies were surprisingly rare.

Animals↗
PubMed1975

[Serological studies on the occurrence of rickettsial infections in Togo (author's transl)].

The incidence of rickettsioses in Togo was examined by means of the microagglutination-technique according to Giroud. Out of 559 sera obtained from different parts of the country the following percentages of positive reactions were found: R. prowazeki 0.2%, R. mooseri: 4.7%, R. conori: 0.4%, R. burneti: 2.0%. It was proved that 1) R. mooseri-infections were more prevalent in adults than in children and adolescents and 2) R. mooseri-infections were found more frequently in the southern regions of the country, whereas R. burneti-infections were more widely distributed in the north of Togo.

Adolescent↗
PubMed1975

Changes in buoyant density relationships of two cell types of Coxiella burneti phase I.

Coxiella burneti phase I, purified from a formalin-inactivated yolk-sac vaccine, was separated into two bands of morphologically distinct cell types when subjected to sucrose gradient centrifugation. Recycling of the less dense, rod-shaped cells in unbuffered sucrose gradients (pH 5.5 to 6.0) resulted in the formation of bands having the location and appearance of the original two bands. Recycling of the denser band of larger ovoid-shaped cells yielded a single band, suggesting that the larger cell type arose from the smaller cell. In contrast to vaccine-derived rickettsiae, live, cell culture-propagated phase I organisms formed a single band in unbuffered sucrose gradients, at the same density as the upper band of the vaccine preparation. Centrifugation of cell culture-derived rickettsiae for 26 to 48 h in sucrose gradients of pH 5.5 resulted in the formation of a second band, at the same density as the lower band of the vaccine preparation. This did not occur in gradients of pH 7.0. Treatment of cell culture-propagated rickettsiae with formalin or germicidal ultraviolet radiation induced a total shift of the less dense cell population to a zone of higher density when centrifuged isopycnically in CsC1 gradients. This density change did not occur in sucrose gradients, suggesting a difference in the effect of these treatments on the permeability of the cell membrane to sucrose and CsC1.

Bacterial Proteins↗
PubMedDate not supplied

Multiple viral and inframicrobial infections detected by immunofluorescence reaction in exfoliated cells from patients with eye or respiratory diseases.

The presence of viral (herpes 1 and 2, influenza A and B, parainfluenza 1, 2, and 3, adenovirus) and inframicrobial (Chlamydia, R. burneti and mycoplasma) antigens was investigated by indirect immunofluorescence reaction in exfoliated cells from 107 patients with chronic eye diseases and 77 patients with chronic respiratory diseases. Single or associated viral or inframicrobial antigens were detected in 80% of the former and in 60% of the latter patients. The proportion of multiple infections was of about 60% in both patient groups.

Adenovirus Infections, Human↗