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PubMed1994

Hemobartonella-like parasites in cynomolgus monkeys (Macaca fascicularis).

Red blood cell parasites were identified electron microscopically in five anemic adult female cynomolgus monkeys (Macaca fascicularis), two of which died during anemic episodes. Organisms typically were 0.3-0.5-micron round, oval, or reniform bodies on the surface or within vacuoles of erythrocytes. Based on their size, location in the erythrocyte, and internal ultrastructural features, organisms were classified as Hemobartonella-like. The relationship between the organisms and the anemias in these monkeys was unclear. This report adds rickettsial erythrocyte infections to the list of latent infections that can complicate research studies with cynomolgus monkeys.

Anaplasmataceae Infections↗
PubMed1996

Scrub typhus infections poorly responsive to antibiotics in northern Thailand.

BACKGROUND: Rickettsia tsutsugamushi, the aetiological agent of scrub typhus, is common in Asia and readily infects visitors to areas where disease transmission occurs. Rapid defervescence after antibiotic treatment is so characteristic that it is used as a diagnostic test for R tsutsugamushi infection. Reports from local physicians that patients with scrub typhus in Chiangrai, northern Thailand responded badly to appropriate antibiotic therapy prompted us to do a prospective clinical evaluation and antibiotic susceptibility testing of human rickettsial isolates. METHODS: The clinical response to doxycycline treatment in patients with early, mild scrub typhus in northern Thailand was compared with the results of treatment in Mae Sod, western Thailand. Prototype and naturally occurring strains of R tsutsugamushi were tested for susceptibility to chloramphenicol and doxycycline in mice and in cell culture. FINDINGS: By the third day of treatment, fever had cleared in all seven patients from Mae Sod, but in only five of the 12 (40%) from Chiangrai (p < 0.01). Median fever clearance time in Chiangrai (80 h; range 15-190) was significantly longer than in Mae Sod (30 h; range 4-58; p < 0.005). Conjunctival suffusion resolved significantly more slowly in Chiangrai (p < 0.05). Antibiotics prevented death in mice infected by Chiangrai strains of R tsutsugamushi less often than after infection by the prototype strain (p < 0.05). Only one of three Chiangrai strains tested in cell culture was fully susceptible to doxycycline. INTERPRETATION: Chloramphenicol-resistant and doxycycline-resistant strains of R tsutsugamushi occur in Chiangrai, Thailand. This is the first evidence of naturally occurring antimicrobial resistance in the genus Rickettsia.

Administration, Oral↗
PubMed2004

Relationship of anti-microbial activity of tetracyclines to their ability to block the L3 to L4 molt of the human filarial parasite Brugia malayi.

The nematode parasites Wuchereria bancrofti, Brugia malayi, and B. timori cause a human disease known as lymphatic filariasis, which afflicts approximately 120 million people worldwide. These organisms are known to contain endosymbiotic bacteria (Wolbachia) that are related to rickettsiae. It has been previously reported that tetracycline blocks the L3 to L4 molt of the filarial parasite B. malayi, and suggested that this was related to their known anti-rickettsial activity. However, this interpretation was tempered by several observations. First, Wolbachia DNA could still be detected in nematodes from tetracycline-treated cultures. In addition, chloramphenicol, which has anti-rickettsial and anti-chlamydial activity, failed to inhibit the molt. These observations could not rule out the possibility that the anti-molting activity of tetracycline is due to pharmacologic activities unrelated to its anti-rickettsial functions. This study shows that chemically modified tetracycline, which does not to have anti-microbial activity, also blocks molting.

Animals↗
PubMed2005

Infection with Anaplasma phagocytophilum in a seronegative patient in Sicily, Italy: case report.

BACKGROUND: Anaplasma phagocytophilum causes human granulocytic anaplasmosis (HGA) in humans, which has been recognized as an emerging tick-borne disease in the United States and Europe. Although about 65 cases of HGA have been reported in Europe, some of them do not fulfill the criteria for confirmed HGA. Confirmation of HGA requires A. phagocytophilum isolation from blood, and/or identification of morulae in granulocytes and/or positive PCR results with subsequent sequencing of the amplicons to demonstrate specific rickettsial DNA. Seroconversion or at least fourfold increase in antibody titers to A. phagocytophilum has been used as criteria for confirmed HGA also. CASE PRESENTATION: Infection with A. phagocytophilum was confirmed by PCR in a patient in Sicily, Italy, who had negative serology for A. phagocytophilum. A fragment of A. phagocytophilum 16S rDNA was amplified by two independent laboratories and sequenced from two separate patient's blood samples. The 16S rDNA sequence was identical in both samples and identical to the sequence of the A. phagocytophilum strain USG3 originally obtained from a dog. CONCLUSION: Infection with A. phagocytophilum was confirmed in a patient without a detectable antibody response against the pathogen. The results reported herein documented the first case of confirmed HGA in Sicily, Italy. These results suggested the possibility of human infections with A. phagocytophilum strains that result in clinical symptoms and laboratory findings confirmatory of HGA but without detectable antibodies against the pathogen.

Anaplasma phagocytophilum↗
PubMed1990

Mechanism of upper gastrointestinal hemorrhage in Mediterranean spotted fever.

Gastrointestinal (GI) hemorrhage is not a common complication of Mediterranean spotted fever (MSF). We describe three MSF cases with upper digestive tract bleeding in patients from Salamanca (Spain) and the results of the histologic studies performed in two of them. Besides the classical clinical triad of the disease (fever, rash and lesion at the site of tick bite, 'tache noire'), these patients presented purpuric rash and hypoalbuminemia, previously identified in severe forms of the disease. The hemorrhagic complication occurred late in the course of the MSF (between 13 and 20 days after the onset of fever) and was the consequence of multiple acute superficial erosions of the gastric mucosa. The histologic substrate of these lesions was identified as a vasculitic process - characteristically lymphohistiocytic - affecting the small vessels of the gastric wall. Rickettsial vascular injury at this level of the digestive tract is histologically similar to that observed in other organs in patients with MSF and may manifest clinically as digestive tract bleeding.

Aged↗
PubMed1990

Analysis of QpRS-specific sequences from Coxiella burnetii.

Coxiella burnetii from acute cases of Q fever possess a plasmid termed QpH1. Chronic isolates contain a plasmid termed QpRS or have QpRS sequences integrated into the chromosome. The correlation between an isolate's plasmid type and the chronic or acute nature of the disease has prompted analysis of unique plasmid sequences to determine if they contain virulence genes. DNA hybridization has determined that a portion of a 3.6-kb EcoR I fragment (epsilon') is unique to QpRS. In vitro transcription/translation (IVTT) of the epsilon' fragment yielded a 55-kDa protein regardless of the cloning orientation, suggesting that transcription resulted from a rickettsial promoter. A translational start site was mapped to the 1.2-kb Pst I-EcoR I subfragment of epsilon' by IVTT. DNA sequencing showed an open reading frame (ORF) of 1485 bp, capable of coding for a protein of ca. 55.9 kDa. This ORF was termed cbbE'. Putative promoter regions of cbbE' included TTTAAT (-35), TATAAT (-10), and a ribosome-binding site GGAGAGA. The ORF ended with a stop codon UAA and was followed by UAG and a potential factor-independent transcription-termination region. In-frame cloning of the 695-bp Pst I subfragment into pUC9 resulted in a fusion protein of ca. 37 kDa, confirming the frame and length of the ORF as predicted by DNA sequencing. The specificity of this gene to QpRS was confirmed by probing DNA from three plasmid groups of C. burnetii, using the internal 695-bp Pst I fragment of cbbE'.

Base Sequence↗
PubMed1978

Erythema chronicum migrans in America.

Erythema chronicum migrans (ECM) developed in a man after a tick bite; the tick was probably lxodes pacificus. Despite extensive laboratory evaluation, including bacterial culture of involved skin, viral and rickettsial titers, biopsy and special stains, animal inoculation, and electron microscopy, the causal agent could not be identified. Although probably unrelated, an elevated measles titer with a twofold drop on serial determinations was of interest. To our knowledge, this report documents the first reported case of ECM acquired in this country in which the tick that caused the disease has been recovered.

Adult↗
PubMed2005

Characterization of a tandem repeat polymorphism in Rickettsia strains.

Mediterranean spotted fever (MSF) is a tick-borne rickettsiosis caused by 'Rickettsia conorii complex' strains. In Portugal, R. conorii and Israeli tick typhus (ITT) are the aetiological agents of this disease. A novel 65 bp tandem repeat was identified by the analysis of the R. conorii Malish 7 whole genome sequence with an appropriate algorithm for searching for repeated sequences. The variable number tandem repeat (VNTR) was named VNTR Rc-65 and this locus was amplified by PCR and sequenced in order to characterize the repeat diversity within different rickettsial strains including Portuguese strains isolated from clinical and vector samples. The VNTR Rc-65 has seven alleles within the rickettsial strains studied and a diversity index value of 0.71, meaning that this locus has a great discriminatory capacity and therefore can be used for identification of closely related strains. PCR amplification of the Rc-65 locus can be used to differentiate between the Portuguese R. conorii Malish-like and Israeli tick typhus strains, enabling a more accurate and rapid identification of these rickettsial isolates.

Animals↗
PubMed1988

Ehrlichiosis: a cause of bone marrow hypoplasia in humans.

Infection with Ehrlichia canis should be suspected in patients with fever, headache, malaise, leukopenia, thrombocytopenia, and a history of recent exposure to ticks. The cytopenia is caused by bone marrow hypoplasia which may be severe. The disease may be confused with spotless Rocky Mountain spotted fever but can be differentiated from this infection serologically with acute and convalescent sea. In humans, recovery has occurred with and without antibiotic therapy. However, prompt antibiotic therapy is advised prior to serologic studies, especially in immunocompromised individuals, splenectomized persons, and patients with AIDS-who may develop a more overwhelming rickettsial infection.

Bone Marrow↗
PubMed1999

Minimal change nephrotic syndrome: a possible complication of ehrlichiosis.

Ehrlichiae are rickettsial organisms recently shown to be human pathogens. Infections often cause fever, myalgia, and hematological abnormalities, and sometimes mild elevation in transaminases, creatinine, and urinary protein. We report a teenager with nephrotic syndrome from minimal change glomerulonephritis and serological evidence of ehrlichiosis. In the appropriate clinical setting, Ehrlichiae should be considered in the etiological assessment of patients with minimal change disease.

Adolescent↗
PubMed1977

Massive occurrence of rickettsiae of the spotted fever group in fowl tampan, Argas persicus, in the Armenian S.S.R.

Fowl tampans (Argas persicus) collected in Oktemberyan in the Armenian S.S.R. in 1974 were found to be massively infected with rickettsiae of the spotted fever (SF) group. One isolated rickettsial strain, designated Armenia 9, is antigenically related to, and probably identical with, strain Armenia 11 and strain B of Rickettsia slovaca, isolated from Dermacentor marginatus ticks. Strain Armenia 9 grows readily in chick embryo yolk sacs and in chick embryo cell (CEC) and L-cell cultures. It causes generalized infection in both soft and hard ticks. A fatal disease was produced in Clethrionomys glareolus after subcutaneous inoculation. Similar inoculation of other small wild rodents (Mus musculus, Microtus arvalis, Apodemus flavicollis), hens and laboratory animals (guinea pigs, white mice and hamsters) resulted only in an antibody response.

Animals↗
PubMed2001

[Murine typhus infected in Oku-etsu area, Fukui Prefecture].

A 15-year-old girl, high school student, became febrile (38-39 degrees C) with chills, sore throat and cough on April 20, 1994. Until the onset, she was healthy and she had been camping with her classmates in a wooded mountainous area in Oku-etsu, Fukui Prefecture. She consulted a local clinic on April 21 and bacampicillin was initially administered and then changed to cefaclor on April 23. However, high body temperature continued and a maclopapular rash appeared on her face on April 24 and gradually spread to her anterior chest and back. Blood examination showed a WBC count of 2,200/microliter, and she was admitted to our hospital on April 25. On admission, peripheral blood data showed leukocytopenia (WBC 2,300/microliter) with 5% atypical lymphocytes. Titers of anti-Rickettsia typhi serum antibodies (IgM, -G) were elevated (1:80, 1:640) and she was diagnosed as having murine typhus. On the second hospital day, 200 mg of minocycline (MINO) was administered per os and her body temperature fell to within the normal limits on the third hospital day. On the 7th hospital day, the skin rash disappeared and she was discharged. Altogether, 320 high school students went camping with this patient. Among them, approximately 30 students had similar symptoms and signs as this case and had been diagnosed suspected viral infection. Twelve students of the 30 were admitted to other hospitals. It was considered that this case was part of an outbreak of murine typhus in the Oku-etsu area, Fukui Prefecture, but no further investigation was performed. Murine typhus is usually a benign disease that is controllable by the administration of MINO. In rare cases, infection can worsen to multiorganic failure, severe complications have been reported in 1-4% of cases, and death has been reported in less than 3%. Recently, it has also been reported that MINO not only has an antibiotic effect, but also play acts as a cytokine modulator in patients with rickettsial infection. Thus, in febrile patients in whom uncommon Rickettsia infection is suspected, serological test for murine typhus should be examined and the immediate administration of MINO is important.

Adolescent↗
PubMed1974

Infectious process in the lungs after intranasal challenge of white mice with Rickettsia prowazekii. A histologic immunoluminescent and electron microscopic study.

The lungs of white mice given intranasal injections of various amounts of Rickettsia prowazekii were studied. Agent parasitism, mainly in the alveolar epithelium and nonciliated cells of bronchiolar epithelium, underlies the infectious process developing in the lungs. Rickettsiae may lodge in these cells without inducing both local and general alterations or a leukocyte response. After being released from the cells they inhabit, rickettsiae evoke acute exudative inflammation. The inflammation is accompanied by marked circulatory disorders, necrosis of exudate cells and vascular thrombosis, which are induced by toxic products of the agent. Polymorphonuclear leukocytes and macrophages represent the main defense mechanism of a host. They ingest and destroy rickettsial organisms. If infection runs a favorable course, phagocytes destroy the rickettsiae, and the organisms are entirely cleared from the lungs.

Administration, Intranasal↗
PubMed1988

Stability of plasmid sequences in an acute Q-fever strain of Coxiella burnetii.

The rickettsial pathogen Coxiella burnetii undergoes a variation in which virulent isolates (phase 1) become avirulent (phase 2) after repeated passage in a non-immunologically competent host. Biochemically, this variation is associated with a lipopolysaccharide modification and possibly other factors. Genetically, the regions of DNA responsible for phase variation have not been identified. We have sought to determine whether the plasmid identified in acute disease isolates, QpH1, which represents approximately 5% of the coding capacity of this organism is involved in phase variation. Plasmids from phase 1 and phase 2 variants (designated QpH1 and QpH2, respectively) were compared by restriction endonuclease digestion and Southern blot hybridization to determine whether sequence changes in the phase 2 plasmid might account for changes in the virulence of phase 2 organisms compared with that of phase 1 cells. Using over 20 different restriction enzymes, no changes in DNA restriction fragment patterns were detected regardless of whether the phase change occurred during egg or tissue culture passage. The plasmid-specific mRNAs produced from metabolically active, purified cells were identical for each phase type. Using QpH1 or QpH2 DNA as a template, the mRNA produced by an E. coli extract was also identical. Finally, the proteins encoded by either plasmid in an in vitro transcription/translation reaction were identical. These data indicate that within the limits of our analysis, the plasmid DNA from C. burnetii phase variants is structurally and functionally the same and is therefore unlikely to be involved in phase variation.

Base Sequence↗
PubMed1983

Rocky Mountain spotted fever in an urban canine population.

A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. For comparison, 137 blood samples from dogs at the Franklin County Dog Pound also were tested. One dog (0.7%) from the comparison group was seropositive to R rickettsii, with a 1:64 titer. The results indicated a nidus of this disease within the city of Columbus, Ohio.

Animals↗
PubMed1990

[Natural Anaplasma marginale infection in 2 cattle herds with different levels of Boophilus microplus tick infestation].

The dynamics of natural infections by Anaplasma marginale was studied in two adjacent dairy farms with different levels of Boophilus microplus infestation. The farms were located in the enzootic area of bovine anaplasmosis of the Northwest of Argentina. The study was carried out in 35 calves from birth in March-August 1985 to March 1986. The infection rate by A. marginale was evaluated by the observation of blood films and by determination of specific antibodies. The degree of infestation by B. microplus was also evaluated. The tick was found all over the year in farm A with peaks of 100 and 95% of infested calves in October and January, respectively. In farm B, B. microplus was found only in December and January with a maximum of 50% of infested calves. Natural infections by A. marginale started in June until the end of the study when 89% (farm A) and 81% (farm B) of the calves proved to be infected. According to the active serological reactors, the rate rose to a maximum of 85% (farm A) and 81% (farm B) at the end of the study. It is remarkable that 69% of primo-infections by A. marginale in farm B occurred when B. microplus was absent. Moreover, no direct relationship between the peaks of tick infestation and primo-infections with the rickettsie was detected in farm A. The authors concluded that B. microplus could have less importance in the transmission of A. marginale than previously assumed under the local conditions.

Anaplasmosis↗
PubMed2006

Causes of fever in adults on the Thai-Myanmar border.

A hospital-based study was conducted along the Thai-Myanmar border to provide greater knowledge of the causes of febrile illness and to determine what zoonotic and vector-borne emerging infectious diseases might be present. A total of 613 adults were enrolled from June 1999 to March 2002. Cases were classified based on clinical findings and laboratory results. An etiologic diagnosis was made for 48% of subjects. Malaria was the most common diagnosis, accounting for 25% of subjects, with two-thirds Plasmodium falciparum. Serologic evidence for leptospirosis was found in 17% of subjects. Other etiologic diagnoses included rickettsial infections, dengue fever, and typhoid. The most frequent clinical diagnoses were nonspecific febrile illness, respiratory infections, and gastroenteritis. Clinical associations were generally not predictive of etiologic diagnosis. Apparent dual diagnoses were common, particularly for malaria and leptospirosis. Findings have been used to modify treatment of unspecified febrile illness in the area.

Adult↗