Exploring the diversity of tick-borne pathogens: The case of bacteria (Anaplasma, Rickettsia, Coxiella and Borrelia) protozoa (Babesia and Theileria) and viruses (Orthonairovirus, tick-borne encephalitis virus and louping ill virus) in the European continent

Ticks are the main vectors for the transmission of bacterial, protist and viral pathogens in Europe affecting wildlife and domestic animals. However, some of them are zoonotic and can cause serious, sometimes fatal, problems in human health. A systematic review in PubMed/MEDLINE database was conducted to determine the spatial distribution and host and tick species ranges of a selection of tick-borne bacteria (Anaplasma spp., Borrelia spp., Coxiella spp., and Rickettsia spp.), protists (Babesia spp. and Theileria spp.), and viruses (Orthonairovirus, and flaviviruses tick-borne encephalitis virus and louping ill virus) on the European continent in a five-year period (November 2017 - November 2022). Only studies using PCR methods were selected, retrieving a total of 429 articles. Overall, up to 85 species of the selected tick-borne pathogens were reported from 36 European countries, and Anaplasma spp. was described in 37% (159/429) of the articles, followed by Babesia spp. (34%, 148/429), Borrelia spp. (34%, 147/429), Rickettsia spp. (33%, 142/429), Theileria spp. (11%, 47/429), tick-borne flaviviruses (9%, 37/429), Orthonairovirus (7%, 28/429) and Coxiella spp. (5%, 20/429). Host and tick ranges included 97 and 50 species, respectively. The highest tick-borne pathogen diversity was detected in domestic animals, and 12 species were shared between humans, wildlife, and domestic hosts, highlighting the following zoonotic species: Anaplasma phagocytophilum, Babesia divergens, Babesia microti, Borrelia afzelii, Borrelia burgdorferi s.s., Borrelia garinii, Borrelia miyamotoi, Crimean-Congo hemorrhagic fever virus, Coxiella burnetii, Rickettsia monacensis and tick-borne encephalitis virus. These results contribute to the implementation of effective interventions for the surveillance and control of tick-borne diseases.

Detection of Coxiella antibodies in ruminants using a SucB recombinant antigen

The detection of Coxiella burnetii in ruminants remains challenging despite the use of new technology and the accumulation of novel knowledge. Serology tools, the primary methods of infection surveillance in veterinary medicine, have limitations. We used recombinant antigen production to develop an ELISA based on the SucB protein, one of the major immunodominant antigens described in humans and laboratory animals. We produced the antigen successfully in an Escherichia coli heterologous system, confirmed by sequencing and mass spectrometry, and seen as a band of ~50 kDa in SDS-PAGE and on western blot analysis. We compared the performance of the recombinant ELISA with a commercial ELISA. We observed agreement of 83.5% and a substantial Cohen κ value of 0.67 in our pilot study.

Wild ungulates as sentinels of flaviviruses and tick-borne zoonotic pathogen circulation: an Italian perspective

BACKGROUND

Vector-borne zoonotic diseases are a concerning issue in Europe. Lyme disease and tick-borne encephalitis virus (TBEV) have been reported in several countries with a large impact on public health; other emerging pathogens, such as Rickettsiales, and mosquito-borne flaviviruses have been increasingly reported. All these pathogens are linked to wild ungulates playing roles as tick feeders, spreaders, and sentinels for pathogen circulation. This study evaluated the prevalence of TBEV, Borrelia burgdorferi sensu lato, Rickettsia spp., Ehrlichia spp., and Coxiella spp. by biomolecular screening of blood samples and ticks collected from wild ungulates. Ungulates were also screened by ELISA and virus neutralization tests for flaviviral antibody detection.

RESULTS

A total of 274 blood samples were collected from several wild ungulate species, as well as 406 Ixodes ricinus, which were feeding on them. Blood samples tested positive for B. burgdorferi s.l. (1.1%; 0-2.3%) and Rickettsia spp. (1.1%; 0-2.3%) and showed an overall flaviviral seroprevalence of 30.6% (22.1-39.2%): 26.1% (17.9-34.3%) for TBEV, 3.6% (0.1-7.1%) for Usutu virus and 0.9% (0-2.7%) for West Nile virus. Ticks were pooled when possible and yielded 331 tick samples that tested positive for B. burgdorferi s.l. (8.8%; 5.8-11.8%), Rickettsia spp. (26.6%; 21.8-31.2%) and Neoehrlichia mikurensis (1.2%; 0-2.4%). TBEV and Coxiella spp. were not detected in either blood or tick samples.

CONCLUSIONS

This research highlighted a high prevalence of several tick-borne zoonotic pathogens and high seroprevalence for flaviviruses in both hilly and alpine areas. For the first time, an alpine chamois tested positive for anti-TBEV antibodies. Ungulate species are of particular interest due to their sentinel role in flavivirus circulation and their indirect role in tick-borne diseases and maintenance as Ixodes feeders and spreaders.

Coxiella co-opts the Glutathione Peroxidase 4 to protect the host cell from oxidative stress-induced cell death

The causative agent of human Q fever, Coxiella burnetii, is highly adapted to infect alveolar macrophages by inhibiting a range of host responses to infection. Despite the clinical and biological importance of this pathogen, the challenges related to genetic manipulation of both C. burnetii and macrophages have limited our knowledge of the mechanisms by which C. burnetii subverts macrophages functions. Here, we used the related bacterium Legionella pneumophila to perform a comprehensive screen of C. burnetii effectors that interfere with innate immune responses and host death using the greater wax moth Galleria mellonella and mouse bone marrow-derived macrophages. We identified MceF (Mitochondrial Coxiella effector protein F), a C. burnetii effector protein that localizes to mitochondria and contributes to host cell survival. MceF was shown to enhance mitochondrial function, delay membrane damage, and decrease mitochondrial ROS production induced by rotenone. Mechanistically, MceF recruits the host antioxidant protein Glutathione Peroxidase 4 (GPX4) to the mitochondria. The protective functions of MceF were absent in primary macrophages lacking GPX4, while overexpression of MceF in human cells protected against oxidative stress-induced cell death. C. burnetii lacking MceF was replication competent in mammalian cells but induced higher mortality in G. mellonella, indicating that MceF modulates the host response to infection. This study reveals an important C. burnetii strategy to subvert macrophage cell death and host immunity and demonstrates that modulation of the host antioxidant system is a viable strategy to promote the success of intracellular bacteria.

Molecular detection of Coxiella burnetii and Coxiella species in rats and chickens from poultry farms in North West Province, South Africa

BACKGROUND

Coxiella burnetii is a bacterial pathogen that causes query fever and coxiellosis in humans and animals, respectively. There is a scarcity of studies on the prevalence of C. burnetii infections in rats and chickens in South Africa.

OBJECTIVE

The aim of this study was to determine the occurrence of C. burnetii in rats and chickens sampled from poultry farms in the North West Province of South Africa.

METHODS

DNA was extracted from rodent kidneys (n = 68) and chicken faeces (n = 52). Two rodent pest species, namely Rattus rattus and Rattus tanezumi, were identified by analysis of CO1 gene sequences. Detection of C. burnetii was carried out using polymerase chain reaction assays targeting 23S rRNA, 16S rRNA and IS111 markers.

RESULTS

C. burnetii was detected in 16.2%, 8.8% and 25% of R. rattus, R. tanezumi and chickens, respectively.

CONCLUSIONS

The findings in this study demonstrate that rodents and chickens are harbouring C. burnetii at sampled poultry farms. There should be frequent screening for C. burnetii in poultry operations. The likelihood of future transmission between rodents and chickens, including humans, also needs to be investigated.

Culture-Negative Endocarditis in an Immunocompromised Patient: A Case of Suspected Bartonella and Coxiella Co-Infection

We present the case of a 23-year-old man with a previous deceased-donor renal transplant maintained on tacrolimus and prednisone who developed culture-negative endocarditis (CNE) of the mitral and aortic valves. He was suspected of being co-infected with Bartonella henselae and Coxiella burnetii, confirmed with serology testing. He was successfully managed with appropriate antibiotics and dual valve replacement.

What do we know about the microbiome of I. ricinus?

I. ricinus is an obligate hematophagous parasitic arthropod that is responsible for the transmission of a wide range of zoonotic pathogens including spirochetes of the genus Borrelia, Rickettsia spp., C. burnetii, Anaplasma phagocytophilum and Francisella tularensis, which are part the tick´s microbiome. Most of the studies focus on "pathogens" and only very few elucidate the role of "non-pathogenic" symbiotic microorganisms in I. ricinus. While most of the members of the microbiome are leading an intracellular lifestyle, they are able to complement tick´s nutrition and stress response having a great impact on tick´s survival and transmission of pathogens. The composition of the tick´s microbiome is not consistent and can be tied to the environment, tick species, developmental stage, or specific organ or tissue. Ovarian tissue harbors a stable microbiome consisting mainly but not exclusively of endosymbiotic bacteria, while the microbiome of the digestive system is rather unstable, and together with salivary glands, is mostly comprised of pathogens. The most prevalent endosymbionts found in ticks are Rickettsia spp., Ricketsiella spp., Coxiella-like and Francisella-like endosymbionts, Spiroplasma spp. and Candidatus Midichloria spp. Since microorganisms can modify ticks' behavior, such as mobility, feeding or saliva production, which results in increased survival rates, we aimed to elucidate the potential, tight relationship, and interaction between bacteria of the I. ricinus microbiome. Here we show that endosymbionts including Coxiella-like spp., can provide I. ricinus with different types of vitamin B (B2, B6, B7, B9) essential for eukaryotic organisms. Furthermore, we hypothesize that survival of Wolbachia spp., or the bacterial pathogen A. phagocytophilum can be supported by the tick itself since coinfection with symbiotic Spiroplasma ixodetis provides I. ricinus with complete metabolic pathway of folate biosynthesis necessary for DNA synthesis and cell division. Manipulation of tick´s endosymbiotic microbiome could present a perspective way of I. ricinus control and regulation of spread of emerging bacterial pathogens.

Recently Evolved Francisella-Like Endosymbiont Outcompetes an Ancient and Evolutionarily Associated Coxiella-Like Endosymbiont in the Lone Star Tick (Amblyomma americanum) Linked to the Alpha-Gal Syndrome

Background

Ticks are hematophagous arthropods that transmit various bacterial, viral, and protozoan pathogens of public health significance. The lone star tick (Amblyomma americanum) is an aggressive human-biting tick that transmits bacterial and viral pathogens, and its bites are suspected of eliciting the alpha-gal syndrome, a newly emerged delayed hypersensitivity following consumption of red meat in the United States. While ongoing studies have attempted to investigate the contribution of different tick-inherent factors to the induction of alpha-gal syndrome, an otherwise understudied aspect is the contribution of the tick microbiome and specifically obligate endosymbionts to the establishment of the alpha-gal syndrome in humans.

Materials and Methods

Here we utilized a high-throughput metagenomic sequencing approach to cataloging the entire microbial communities residing within different developmental stages and tissues of unfed and blood-fed ticks from laboratory-maintained ticks and three new geographical locations in the United States. The Quantitative Insights Into Microbial Ecology (QIIME2) pipeline was used to perform data analysis and taxonomic classification. Moreover, using a SparCC (Sparse Correlations for Compositional data) network construction model, we investigated potential interactions between members of the microbial communities from laboratory-maintained and field-collected ticks.

Results

Overall, Francisellaceae was the most dominant bacteria identified in the microbiome of both laboratory-raised and field-collected Am. americanum across all tissues and developmental stages. Likewise, microbial diversity was seen to be significantly higher in field-collected ticks compared with laboratory-maintained ticks as seen with a higher number of both Operational Taxonomic Units and measures of species richness. Several potential positive and negative correlations were identified from our network analysis. We observed a strong positive correlation between Francisellaceae, Rickettsiaceae, and Midichloriaceae in both developmental stages and tissues from laboratory-maintained ticks, whereas ovarian tissues had a strong positive correlation of bacteria in the family Xanthobacteraceae and Rhizobiaceae. A negative interaction was observed between Coxiellaceae and Francisellaceae in Illinois, and all the bacteria detected from ticks from Delaware were negatively correlated.

Conclusion

This study is the first to catalog the microbiome of Am. americanum throughout its developmental stages and different tissue niches and report the potential replacement of Coxiellaceae by Francisellaceae across developmental stages and tissues tested except in ovarian tissues. These unique and significant findings advance our knowledge and open a new avenue of research to further understand the role of tick microbiome in tick-borne diseases and develop a holistic strategy to control alpha-gal syndrome.

Pathogens, endosymbionts, and blood-meal sources of host-seeking ticks in the fast-changing Maasai Mara wildlife ecosystem

The role of questing ticks in the epidemiology of tick-borne diseases in Kenya's Maasai Mara National Reserve (MMNR), an ecosystem with intensified human-wildlife-livestock interactions, remains poorly understood. We surveyed the diversity of questing ticks, their blood-meal hosts, and tick-borne pathogens to understand potential effects on human and livestock health. By flagging and hand-picking from vegetation in 25 localities, we collected 1,465 host-seeking ticks, mostly Rhipicephalus and Amblyomma species identified by morphology and molecular analysis. We used PCR with high-resolution melting (HRM) analysis and sequencing to identify Anaplasma, Babesia, Coxiella, Ehrlichia, Rickettsia, and Theileria pathogens and blood-meal remnants in 231 tick pools. We detected blood-meals from humans, wildebeest, and African buffalo in Rh. appendiculatus, goat in Rh. evertsi, sheep in Am. gemma, and cattle in Am. variegatum. Rickettsia africae was detected in Am. gemma (MIR = 3.10) that had fed on sheep and in Am. variegatum (MIR = 250) that had fed on cattle. We found Rickettsia spp. in Am. gemma (MIR = 9.29) and Rh. evertsi (MIR = 200), Anaplasma ovis in Rh. appendiculatus (MIR = 0.89) and Rh. evertsi (MIR = 200), Anaplasma bovis in Rh. appendiculatus (MIR = 0.89), and Theileria parva in Rh. appendiculatus (MIR = 24). No Babesia, Ehrlichia, or Coxiella pathogens were detected. Unexpectedly, species-specific Coxiella sp. endosymbionts were detected in all tick genera (174/231 pools), which may affect tick physiology and vector competence. These findings show that ticks from the MMNR are infected with zoonotic R. africae and unclassified Rickettsia spp., demonstrating risk of African tick-bite fever and other spotted-fever group rickettsioses to locals and visitors. The protozoan pathogens identified may also pose risk to livestock production. The diverse vertebrate blood-meals of questing ticks in this ecosystem including humans, wildlife, and domestic animals, may amplify transmission of tick-borne zoonoses and livestock diseases.

Diagnosis of Coxiella burnetii infection: comparison of a whole blood interferon-gamma production assay and a Coxiella ELISPOT

Diagnosis of ongoing or past infection with Coxiella burnetii, the causative agent of Q fever, relies heavily on serology: the measurement of C. burnetii-specific antibodies, reflecting the host’s humoral immune response. However, cell-mediated immune responses play an important, probably even more relevant, role in infections caused by the intracellular C. burnetii bacterium. Recent studies have investigated interferon-gamma (IFN-γ) based assays, including a whole-blood IFN-γ production assay and a Coxiella enzyme-linked immunospot (Coxiella ELISPOT), as potential diagnostic tools for Q fever diagnosis. Both are in-house developed assays using stimulating antigens of different origin. The main objective of this study was to compare the test performance of the IFN-γ production assay and the Coxiella ELISPOT for detecting a cellular immune response to C. burnetii in Q fever patients, and to assess the correlation between both assays. To that end, both tests were performed in a well-defined patient group of chronic Q fever patients (n = 16) and a group of healthy seronegative individuals (n = 17). Among patients, both the Coxiella ELISPOT and the IFN-γ production assay detected positive response in 14/16. Among controls, none were positive in the Coxiella ELISPOT, whereas the IFN-γ production assay detected positive results in 1/17 and 3/17, when using Henzerling and Nine Mile as stimulating antigens, respectively. These results suggest the Coxiella ELISPOT has a somewhat higher specificity than the IFN-γ production assay when Nine Mile is used as antigen stimulus. The assays showed moderate correlation: the Spearman correlation coefficient r ranged between 0.37–0.60, depending on the antigens used. Further investigation of the diagnostic potential for C. burnetii infection of both assays is warranted.

Studies on the physiology of Rickettsiae. IV. Folic acids of Coxiella burnetii

Mattheis, Martha S. (University of Kansas, Lawrence), M. Silverman, and D. Paretsky. Studies on the physiology of rickettsiae. IV. Folic acids of Coxiella burnetii. J. Bacteriol. 85:37-41. 1963.-Yolk, yolk sac, and embryo tissues of uninfected eggs, and those infected with Coxiella burnetii, were analyzed for folic acid derivatives by employing diethylaminoethyl (DEAE)-cellulose column chromatography. Infected tissues contained quantitatively less folate, but the elution profiles of both infected and uninfected tissues were identical. Purified C. burnetii contained some types of folate apparently unique to these rickettsiae, and not found in infected tissue. The major folate fraction of C. burnetii was partially characterized by (i) elution position from DEAE columns; (ii) treatment with conjugase; (iii) growth response by Lactobacillus casei, Streptococcus faecalis R, and Pediococcus cerevisiae; and (iv) response to oxidation, reduction, and formylation.

The pathogenesis of Coxsackie group B viruses in experimental infection

The experimental findings show that in mouse-adapted strains of different Coxsackie group B types of virus, distinctly varied patterns of pathogenesis exist. In the particular host population under study, both of the B-3 strains examined are peculiarly cardiotropic for 17-day-old mice and adult mice. In contrast, the B-1 strain, while mildly cardiotropic for sucklings, neither propagates nor produces lesions in the 17-day weanlings. The age factor does not seem to have any effect upon two strains of B-5 viruses which show the same degree of moderate cardiotropism in sucklings and weanlings.It can be seen from observations made upon the brown fat that lesions are produced in adult mice with all but B-2 virus. Interpretation of the heart lesion, however, is complicated by the appearance of heart lesions in control animals of this age. These heart lesions were not observed in the control sucklings or weanlings. In spite of this, there is evidence that the B-3 virus induces specific heart lesions in adult mice.It would appear that the B-2, B-4, and the Kita strain of B-5 provoke a marked inflammatory cell response in the brain which distinguishes them from the other strains.

METABOLIC ACTIVITY IN COXIELLA BURNETII

Ormsbee, Richard A. (Rocky Mountain Laboratory, Hamilton, Mont.), and Marius G. Peacock. Metabolic activity in Coxiella burnetii. J. Bacteriol. 88:1205-1210. 1964.-Purified suspensions of Coxiella burnetii were shown to utilize alpha-ketoglutarate, succinate, fumarate, malate, oxaloacetate, pyruvate, glutamate, and serine. The addition of nicotinamide adenine dinucleotide(+) was necessary to elicit the maximal rate of oxygen uptake with l-glutamate as substrate, but was unnecessary when other substrates were employed. It was concluded that the Krebs cycle of intermediary carbohydrate metabolism probably operates within C. burnetii, and that pyruvate is the chief energy source.

CONVERSION OF THE PHASE I ANTIGEN OF COXIELLA BURNETII TO HAPTEN BY PHENOL TREATMENT

Anacker, R. L. (Rocky Mountain Laboratory, Hamilton, Mont.), W. T. Haskins, D. B. Lackman, E. Ribi, and E. G. Pickens. Conversion of the phase I antigen of Coxiella burnetii to hapten by phenol treatment. J. Bacteriol. 85:1165-1170. 1963.-Trichloroacetic acid extracts of Coxiella burnetii are converted to hapten by treatment with phenol. Such extracts react, like the original trichloroacetic acid extract, at high dilution in the complement-fixation test and produce zones of precipitate with specific antibody in gel diffusion tests; but, unlike the parent extract, injection of the phenol-treated extract neither induces resistance to challenge in guinea pigs nor antibody formation in guinea pigs, rabbits, or mice. This loss of antigenicity is correlated with removal of protein from the original product.

STUDIES ON THE PHYSIOLOGY OF RICKETTSIAE. V. METABOLISM OF CARBAMYL PHOSPHATE BY COXIELLA BURNETII

Mallavia, L. (University of Kansas, Lawrence) and D. Paretsky. Studies on the physiology of rickettsiae. V. Metabolism of carbamyl phosphate by Coxiella burnetii. J. Bacteriol. 86:232-238. 1963.-Preparations of disrupted Coxiella burnetii catalyze synthesis of citrulline from ornithine and carbamyl phosphate at an optimal pH of 7.0 to 7.5. Rickettsial synthesis of the pyrimidine precursor, ureidosuccinate, is demonstrated and confirmed by isolating C(14)-labeled ureidosuccinate from reaction mixtures of carbamyl phosphate and labeled aspartate. The data suggest a further rickettsial synthesis of orotate and imply rickettsial competence for host-independent pyrimidine synthesis.

ELECTRON MICROSCOPIC OBSERVATIONS OF THE DEVELOPMENT OF COXIELLA BURNETII IN THE CHICK YOLK SAC

Anacker, R. L. (Rocky Mountain Laboratory, Hamilton, Mont.), K. Fukushi, E. G. Pickens, and D. B. Lackman. Electron microscopic observations of the development of Coxiella burnetii in the chick yolk sac. J. Bacteriol. 88:1130-1138. 1964.-Yolk sac material, obtained daily over a period of 1 week from embryos inoculated with seed of phase I Coxiella burnetii strain Ohio 314 containing 250 units of penicillin, was examined by electron microscopy and other techniques for the presence of rickettsiae. The concentration of rickettsiae in the yolk sac, as determined by electron microscopy, light microscopy, the complement-fixation test, recovery of organisms, and mouse infectivity, was low for the first 3 days, increased rapidly 3 to 5 days after infection, and then remained relatively constant. Rickettsiae in 3- to 7-day cultures, when observed by electron microscopy, had dense fibrillar centers surrounded by less-dense cytoplasmic material containing granules approximately 15 mmu in diameter. The whole was enclosed by multiple external layers. Many appeared to be in various stages of binary fission, and one form which contained a cross-wall was observed. These forms readily combined with ferritin-labeled specific antibody. In rare instances, several kinds of "atypical" forms which did not combine with ferritin-labeled antibody were found in the cytoplasm of yolk-sac cells 4 to 5 days after inoculation; it is not certain whether these forms are artifacts or normal stages in the maturation of C. burnetii. These atypical forms were not observed in subsequent experiments in which embryonated eggs were inoculated with doses of penicillin varying from 0 to 4,000 units per egg.

NEW METHOD FOR PURIFYING COXIELLA BURNETII BY DEXTRAN SULFATE PRECIPITATION FOLLOWED BY CENTRIFUGATION

This paper describes a simple method for purifying Coxiella burnetii cultivated in the chick embryo. The procedure is based upon the preliminary clarification of infected whole-egg suspensions by precipitating the low-density lipoproteins and other extraneous solids with dextran sulfate, calcium chloride, and sodium chloride solutions, and then concentrating the rickettsiae by centrifugation.

Quinolones in the treatment of lower respiratory tract infections caused by intracellular pathogens

Intracellular pathogens are inhibited to varying degrees, depending upon the strain of the organism and the quinolone tested. Quinolones achieve levels in the lower respiratory tract that equal or exceed serum concentrations, and they also achieve good intracellular concentrations. Experimental models of intracellular infection have demonstrated the efficacy of ciprofloxacin, difloxacin, fleroxacin, ofloxacin and pefloxacin. Animal models of experimental legionellosis have confirmed in vivo their efficacy in this field. Thus, quinolones appear to be a safe and efficacious alternative treatment in lower respiratory tract infection (LRTI) due to intracellular pathogens. Considering the in vitro and experimental studies, quinolones should play an important role in the treatment of LRTI caused by intracellular pathogens, and prospective controlled studies are strongly recommended.

Antibiotic treatment of rickettsiosis, recent advances and current concepts

The author reviews the recent advances in the treatment of Mediterranean Spotted Fever and Q fever. In mediterranean spotted fever (M.S.F.), in vitro and preliminary in vivo data support the place of quinolones and josamycin in the treatment of M.S.F. In children josamycin could become the first choice drug as well as in pregnant woman. In Q fever chronic disease should be treated using a combination of antibiotic (doxycycline + quinolones) for a minimum of 3 years.

A novel ubiquitous protein 'chaperonin' supports the endosymbiotic origin of mitochondrion and plant chloroplast

The deduced amino acid sequences for a major mitochondrial protein (designated P1, related to the 'chaperonin' family of proteins) from human and Chinese hamster cells show extensive similarity (greater than 60% identity observed over the entire length) with a related protein present in evolutionarily as divergent organisms as Escherichia coli, Coxiella burnetii, Mycobacterium species, cyanobacteria as well as in yeast mitochondria and higher plant chloroplasts. Of the different groups of bacteria for which sequence data is available, maximum similarity of the mammalian/yeast P1 protein is observed with the corresponding protein from purple bacteria (especially C. burnetii) while the protein from plant chloroplasts exhibited highest similarity with the corresponding protein from cyanobacteria. The sequence data for this protein thus support the contention that the endosymbiont that gave rise to mitochondrion was a member of purple bacteria, while plant chloroplast originated from a member of the cyanobacterial lineage.

Tumor necrosis factor in malaria-induced abortion

The cause of fetal loss in malaria is not known. We report that a small (1.5-5.0 micrograms) intravenous dose of recombinant human tumor necrosis factor (TNF) caused fetal death and abortion in 16 day pregnant mice that were carrying low densities of Plasmodium vinckei. In contrast, 50 micrograms human TNF did not cause fetal death or abortion in uninfected 16 day pregnant mice. Endogenous TNF, which was not detectable in plasma of low parasitemia animals, pregnant or not, was present (1.6 +/- 0.9 ng/ml) in samples from malarial pregnant mice when, on day 17, parasitemia was high and the first signs of impending abortion were evident. No TNF was detectable in the plasma of uninfected mice at day 17 of pregnancy. A small dose of TNF also caused fetal death in 16 day pregnant mice that had received an intravenous injection of Coxiella burneti extract 9-10 days earlier. Thus, TNF-induced abortion may occur in a range of infections in which systemic macrophage activation occurs and a trigger for TNF release is present.

'Ring' granulomas in cytomegalovirus hepatitis

A liver biopsy specimen obtained from a patient with cytomegalovirus hepatitis demonstrated "ring" granulomas similar to those previously described as characteristic of acute Coxiella burnetii infection. Q fever is not the only infectious disease in which fibrinoid rings may form within granulomatous foci.

Mitogenic and protective activity associated with a lipopolysaccharide from Coxiella burnetii

A purified lipopolysaccharide (LPS) isolated from the rickettsial agent of Q fever, Coxiella burnetii phase 1, possesses some of the in vivo and in vitro biological properties previously only associated with bacterial endotoxins. The Coxiella LPS is mitogenic for guinea pig leukocytes, induces non-specific resistance in mice to virulent Candida albicans, causes dermal Schwartzman reactions, and is positive by the limulus lysate assay.

[Mononucleosis syndrome and thrombocytopenic purpura in Q fever (Rickettsia burneti)]

Case of a patient with a mononucleosis syndrome and thrombocytopenic purpura during Q Fever. This etiology could lead to a systematic search for a rickettsial cause for such a symptomatology with a negative Paul-Bunnell-Davidson reaction.

[Rickettsial arteritis due to Coxiella Burnetii]

Case of an 48 year old man who has presented from 1968 to 1973 a lot of diseases such as: --mitral incompletence discovered in 1968 in Madagascar island in spite of many previous clinical examinations; --acute pneumonia and heart failure in January 1973. Serological reactions of Ricketsia were quite positive; --acute thrombosis of right humeral artery in May 1973. It has been treated by surgical way, bay "desobstruction" and by pass and medical treatment chloramphenicol). Pathologic endartery has been inoculated to an hamster, cobaye. These animal became feverish, and presented an inflammation of testis. A least serological reaction of Ricketsia became positive for all of them; --few weeks, thrombosis of left femoral and posterior tibial arteries treated by surgical and medical ways. Some commens are exposed about evolution of Coxiella Burneti infections, about the frequency of arterial and cardiac lesions, and about the effect of tifomycine which seems to be decreasing and the action of cycline (doxicycline).

Q fever and animal abortion in Cyprus

Seventy-eight British soldiers stationed in the Eastern Sovereign Base Area (ESBA) in Cyprus contracted Q fever in the period December 1974 to June 1975. Pneumonia developed in 59% of cases. Of 31 patients tested, 81% had biochemical evidence of hepatitis although only one became clinically jaundiced. Three patients (4%) suffered pericarditis. Treatment with tetracycline had no apparent effect on the course of the disease. Investigation revealed an abortion epidemic involving 21 mixed flocks of sheep and goats in the south-eastern coastal region. 11 of the flocks grazed in and around the ESBA. A serological survey of 10 affected flocks, and evidence collected from previous years, indicated that the abortion epidemic was the result of infection with Coxiella burneti. Infection in the humans was almost certainly acquired by inhalation of dust from brush contaminated with rickettsial parturition products of the aborting flocks. A human serological survey revealed a number of cases of subclinical Q fever in a susceptivle military population, and an asymptomatic epidemic in a largely immune local position.

Letter: Glomerulonephritis Associated with Coxiella burnetii tendocarditis

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Changes in hepatic glycogen, protein, and ribonucleic acid synthesis, and some effects of cortisol, during Q fever

Liver glycogen is depleted in guinea pigs infected with Coxiella burneti. Syntheses of the glycogen precursors uridine triphosphate and uridine diphosphate glucose are unaffected during Q fever, but glycogen synthetase activity is inhibited. Exogenous cortisol relieves this inhibition in infected animals. Orotate and amino acids are more rapidly incorporated into ribonucleic acid and protein during infection. It is proposed that the biochemical defect in the synthesis of glycogen lies in the inactivation of glycogen synthetase.