Plaque assay for Rickettsia mooseri in tissue samples.
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Animals↗
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Results for “Rickettsia typhi”
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An apparent outbreak of rickettsial illness in Costa Rica, 1974.
A focal outbreak of highly fatal disease occurred in eastern Costa Rica in 1974. No rickettsial spotted fevers have previously been reported in Costa Rica. Nevertheless, the available evidence points to an unidentified rickettsial pathogen, probably of the spotted fever group, as the agent responsible for this outbreak.
Adolescent↗
Some biological properties of an endotoxic lipopolysaccharide from the typhus group rickettsiae.
A lipophilic thermostable lipopolysaccharide (LPS) complex was isolated by phenol extraction from purified suspensions of the typhus group rickettsiae. The LPS complex is antigenic and possesses some endotoxic properties such as toxicity for actinomycin D-treated mice, pyrogenicity for rabbits and guinea pigs, ability to elicit hypothermia in white rats and local Schwartzman reaction and active cutaneous anaphylaxis in rabbits.
Anaphylaxis↗
[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↗
[Bovine serum factor neutralizing the toxic effects of R. mooseri].
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Animals↗
[The effect of various antibiotics on the formation of typhus antibodies following immunization with typhus vaccine].
It was shown that administration in the course of one week, before or after a single use of killed or chemical typhoid vaccine of dibiomycin, biomycin, or biomycin in combination with erythromycin in comparatively high doses produced no negative effect of the production of typhus antibodies and the intensity of antitoxic immunity in albino mice. The same antibiotics failed to influence the antibody formation in guinea pigs if they produced no toxic effect on the animals; but in case of development of toxic phenomena connected with the administration of the mentioned antibiotics a strong depression of antibody production was observed in guinea pigs.
Animals↗
Antibody to Rickettsia mooseri erythrocyte-sensitizing substance.
Erythrocyte-sensitizing antigens from Rickettsia mooseri (R. typhi) were found to bind to rabbit erythrocytes. Upon reintroduction into the donor, such antigen-sensitized cells caused the production of antibodies of restricted serological reactivity.
Animals↗
Biological properties of Rickettsia prowazekii strains isolated from flying squirrels.
Four strains of Rickettsia prowazekii, isolated from flying squirrels (Glaucomys volans volans) from Florida and Virginia, were compared with other strains of the typhus biotype, two previously established strains each of R. prowazekii and R. typhi and one strain of R. canada, for similarities in a number of unrelated phenotypic characteristics. R. akari served as a spotted fever biotype control. All strains produced small plaques on chicken embryo cell monolayers that were clearly recognized only after 10 days of incubation at 32 degrees C. All strains were highly susceptible to erythromycin. The Renografin density gradient centrifugation procedure of separating rickettsiae from the infected yolk sacs of surviving chicken embryos was equally satisfactory in all cases and resulted in moderate to large yields of purified rickettsiae. There was relatively small variation in specific hemolytic activity or specific CO(2) formation from glutamate. None of the strains catabolized glucose. There was some strain variation in virulence for the chicken embryo, but none of the above tests separated the three species of the typhus biotype. On the other hand, R. akari was clearly distinguished by its more rapid plaque formation and by higher resistance to erythromycin. It is concluded that by the tests conducted thus far, the biological properties of the flying squirrel strains do not differ substantially from those of other strains of the typhus biotype.
Animals↗
[Seroepidemiological investigations in domestic ruminants from Egypt, Somalia and Jordan for the demonstration of complement fixing antibodies against Rickettsia and Chlamydia (author's transl)].
1450 random serum samples of domestic ruminants from Egypt, Somalia and Jordan were investigated for complement fixing antibodies against Rickettsia and Chlamydia. Between 1.5 and 3.4% of the samples from the animals investigated had antibodies against the RMSF-group of Rickettsia, with exception of the sera from Somalian cattle and sheep from Jordan. Antibodies against Rickettsia of the Typhus-group were found in 4 cattle and 1 goat from Jordan and 2 sheep from Egypt; by agglutination test with type-specific antigen they were identified as antibodies against R. typhi. Using 2 different antigens, antibodies against Coxiella burnetii were found in every population tested. The prevalence was 2.0 to 12.2%, with the exception of cattle in Somalia, where only 1 positive serum (0.2%) was found. 27% of the serum samples from Jordan and 22% from Egypt but none of the 802 samples from Somalia had antibodies against Chlamydia. The results are discussed under an epidemiological point of view.
Animals↗
Limits of rickettsial infectivity.
Seven species of pathogenic rickettsiae were compared in five assay systems for group, species, strain, and phase differences in infectivity. The species examined include Rickettsia prowazekii (Breinl and Cairo 3 strains), R. typhi, R. canada, R. rickettsii (Sheila Smith and R strains), R. conorii, R. sibirica, and Coxiella burnetii in phases I and II. Pathogenicity was charcterized in terms of fever in guinea pigs. All comparisons of infectivity and pathogenicity were described in terms of numbers of rickettsiae in the inocula, as determined by direct rickettsial count. The data characterize the various species and strains of rickettsiae in quantitative terms, which are also estimates of the sensitivity of the assay systems used. Phase I C. burnetii was found to be the most, and R. canada the least, infective of the species examined. In general the primary chicken embryo cell culture system proved to be the most, and that of the mouse the least, sensitive assay system.
Animals↗
Biochemical characteristics of typhus group rickettsiae with special attention to the Rickettsia prowazekii strains isolated from flying squirrels.
Six strains of Rickettsia prowazekii, two derived from human infections and four isolated from flying squirrels, two strains of R. typhi, and the single available strain of R. canada, were characterized by several biochemical procedures. The electrophoretic patterns on polyacrylamide gels of rickettsial proteins solubilized by sodium dodecyl sulfate revealed several species differences, but strains of the same species appeared to have identical patterns. Cytoplasmic fractions of the rickettsiae were examined for enzymatic activities and for polyacrylamide gel isoelectric focusing patterns. Some species differences were encountered in the activities or ratios of activities of glutamate-oxaloacetate transaminase, glutamate dehydrogenase, and malate dehydrogenase. When polyacrylamide gels were stained for malate dehydrogenase after electrophoresis, a single band became apparent with single extracts or mixtures of two strains of R. prowazekii, but two bands were seen with mixtures of a strain of R. prowazekii and one of R. typhi. The isoelectric focusing patterns of the soluble proteins revealed numerous species differences, especially between R. canada and the other two species, and a few differences among the strains of R. prowazekii. The patterns of the two human strains, Breinl and E(R), differed in at least one location, and both differed from the flying squirrel strains in the displacement of one band. One of the flying squirrel strains, GvF-16, contained a protein band not seen in the other five strains. Despite these minor differences, a striking similarity was revealed by all the biochemical tests performed between the R. prowazekii strains of human and flying squirrel origin.
Animals↗
Tetracyclines, chloramphenicol, erythromycin, and clindamycin.
Tetracyclines are active in vitro against most urinary tract pathogens, Chlamydia, Mycoplasma pneumoniae, Brucella, rickettsiae, and Nocardia. Chloramphenicol is used primarily for anaerobic infections, Haemophilus influenzae meningitis, and infections due to Salmonella typhi. Erythromycin is active in vitro against M. pneumoniae, Streptococcus pneumoniae, and group A beta-hemolytic streptococci. Erythromycin may be used as prophylactic therapy for subacute bacterial endocarditis and for recurrence of acute rheumatic fever in patients who are allergic to penicillin. Clindamycin should be used only for the treatment of anaerobic infections. Tetracycline may cause gastrointestinal upset; phototoxic dermatitis; hepatitis, especially in pregnant females; discoloration of teeth and bone dysplasia in the human fetus and children; and suprainfections, especially oral and anogenital candidiasis. Tetracycline should be used with caution in patients with renal insufficiency. The most important toxic effect of chloramphenicol is bone marrow suppression, which is dose related and idiosyncratic. The incidence of undesirable side effects associated with the use of erythromycin is low. Gastrointestinal irritation is the most common; cholestatic hepatitis may occur with erythromycin estolate. Pseudomembranous colitis is the most important toxic effect associated with clindamycin.
Anaerobiosis↗
Surveillance of some infectious diseases among aircrew personnel in Southeast Asia.
A 2-year analysis of specimens among aircrew personnel in Southeast Asia is reported. Stool specimens were examined for intestinal parasites and enteric bacteria, blood smears for blood parasites, and sera tested for transaminases (SGOT) and antibodies to Entamoeba histolytica, Toxoplasma gondii, Chikungunya and Japanese encephalitis viruses, Rickettsia tsutsugamushi, Leptospira sp. and Pseudomonas pseudomallei. One to four specimens each were obtained from 537 adult males and 20 females. There were 56 subjects with intestinal parasites as follows: Giardia lamblia (3.8%), Endolimax nana (2.6%), Entamoeba histolytica (1.4%), Entamoeba hartmanni (0.9%), Entamoeba coli (0.7%), Trichiuris trichiura (1.7%), Ascaris lumbricoides (1.4%), hookworm (0.9%), and Clonorchis sinensis (1.2%). Two individuals had malaria, Plasmodium vivax (0.6%). Pathogenic enteric bacteria were isolated from seven stool specimens; Shigella groups B and D (0.9%), Salmonella paratyphi (0.3%), and Arizona group (0.9%). Significantly elevated SGOT levels were found in 0.9% and antibodies to Japanese encephalitis virus in 1.5%, to Rickettsia tsutsugamushi in 1.2%, to Pseudomonas pseudomallei in 0.3%, to Entamoeba histolytica in 0.9% and to Toxoplasma gondii in 10.1%. No antibodies were found to Chikungunya virus or Leptospira sp.
Aerospace Medicine↗