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PubMed1981

Rickettsialpox: report of an outbreak and a contemporary review.

Rickettsialpox is a mild illness characterized by the appearance of a primary eschar at the site of a mite bite followed by fever, headache, and a papulovesicular rash. It can be confused with a variety of illnesses including several other rickettsial diseases and chickenpox. R. akari, the etiologic agent, is a rickettsia belonging to the spotted fever group (SFG) of rickettsial illnesses. In spite of significant serologic cross-reactivity with other SFG agents, there is no convincing evidence of cross-immunity to these agents after recovery from rickettsialpox. Tetracyclinie is the drug of choice in the treatment of this disease.

Adult↗
PubMed1991

Ectoparasites of commensal rodents in Sulawesi Utara, Indonesia, with notes on species of medical importance.

Ectoparasite records are presented for four species of commensal murid rodents (Rattus rattus palelae Miller & Hollister, R. argentiventer (Robinson & Kloss), R. exulans (Peale) and Mus musculus castaneus Waterhouse) in Sulawesi Utara, with particular reference to the potential for these arthropods to bite and transmit pathogens to humans. The flea, Xenopsylla cheopis (Rothschild), was most common on R.r. palelae and is capable of transmitting plague and other pathogens to humans although no current foci for these diseases are known in Sulawesi. Hoplopleura pacifica Ewing and Polyplax spinulosa (Burmeister) sucking lice parasitized all three Rattus species although H. pacifica was mainly associated with R. exulans and P. spinulosa with R.r. palelae. These lice do not bite humans but may be intramurid vectors of murine typhus and other zoonoses. The mites Laelaps echidnina Berlese and L. nuttalli Hirst were both collected; the latter was recorded from all four murid species, mainly R. exulans. The mite Ornithonyssus bacoti Hirst was rare. Only one chigger mite, Walchiella oudemansi (Walch), was retrieved from murids (from R. exulans) and a single Leptotrombidium deliense (Walch) chigger was taken from a human subject. Although L. deliense is a significant vector of scrub typhus, a disease known from Sulawesi, the L. deliense-R. argentiventer relationship frequently noted in the ecology of this rickettsial disease, was not evident in this survey. Other ectoparasites collected from murids were the ticks, Ixodes granulatus Supino (first record for Sulawesi), Haemaphysalis sp. and Dermacentor sp., the mites Myocoptes musculinus (Koch) and Listrophoroides cucullatus (Trouessart), acarids and a uropodid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Scrub typhus and tropical rickettsioses.

PURPOSE OF REVIEW: Recent developments in molecular taxonomic methods have led to a reclassification of rickettsial diseases. The agent responsible for scrub typhus (Orientia tsutsugamushi ) has been removed from the genus Rickettsia and a bewildering array of new rickettsial pathogens have been described. An update of recent research findings is therefore particularly timely for the nonspecialist physician. RECENT FINDINGS: An estimated one billion people are at risk for scrub typhus and an estimated one million cases occur annually. The disease appears to be re-emerging in Japan, with seasonal transmission. O. tsutsugamushi has evolved a variety of mechanisms to remain viable in its intracellular habitat. Slowing the release of intracellular calcium inhibits apoptosis of macrophages. Subsets of chemokine genes are induced in infected cells, some in response to transcription factor activator protein 1. Cardiac involvement is uncommon and clinical complications are predominantly pulmonary. Serious pneumonitis occurred in 22% of Chinese patients. Dual infections with leptospirosis have been reported. Standardized diagnostic tests are being developed and attempts to improve treatment of women and children are being made. Of the numerous tick-borne rickettsioses identified in recent years, African tick-bite fever appears to be of particular importance to travellers. The newly described flea-borne spotted fever caused by Rickettsia felis may be global in distribution. SUMMARY: Rash and fever in a returning traveler could be rickettsial and presumptive doxycycline treatment can be curative. Recent research findings raise more questions than answers and should stimulate much needed research.

Animals↗
PubMed1990

Prevalence of antibodies to Rickettsia conorii Coxiella burnetii and Rickettsia typhi in Salamanca Province (Spain). Serosurvey in the human population.

The Salamanca Province of Spain is an endemic zone for Mediterranean spotted fever. In this area, only one case of Q fever has been reported and typhus group rickettsial diseases have never been diagnosed. To obtain a panoramic view of the presence of antibodies to the most ubiquitous rickettsial agents, 400 sera specimens from a statistically representative sample of the human population of Salamanca City and its surrounding province were subjected to indirect microimmunofluorescent test for antibodies against Rickettsia conorii, Coxiella burnetti, phase II, and Rickettsia typhi antigens. Titers greater than or equal to 1:40 to R. conorii were found in 73.5% of the sera. Positivity was more common in subjects who reported closer contact with the natural environment and/or with domestic animals. Seropositivity to C. burnetti, phase II, was detected in 50.2% of sera. These positive cases were related to rural environmental factors and to previous contact with animals. The frequency of antibodies increased with age showing a progressive exposure to the rickettsial antigen. The prevalence of antibodies to R. conorii and C. burnetii in the human population of Salamanca Province is higher than that reported from any other geographic zone. The study of antibodies to R. typhi showed that 12.5% of the sera had titers greater than or equal to 1:40. According to our results, seropositivity to this rickettsial antigen cannot be related to any particular group of population nor interpreted totally as cross reactivity with R. conorii. Our data show a wide distribution of R. conorii and C. burnetii antigens in Salamanca Province, and also indicate the presence of R. typhi antigens in this area.

Adolescent↗
PubMed2003

Pathogenic rickettsiae as bioterrorism agents.

The diseases caused by rickettsiae vary from mild to severe clinical presentations, with case fatality ranging from none to over 30%. The severity of rickettsial diseases has been associated with age, delayed diagnosis, hepatic and renal dysfunction, central nervous system abnormalities, and pulmonary compromise. Despite the variability in clinical presentations many pathogenic rickettsiae cause debilitating diseases, any one of which could be used as a potential biological weapon. While Rickettsia prowazekii, R. rickettsii, and Coxiella burnetii pose serious problems and are currently considered bioterrorism agents, several other species could cause havoc once intentionally released into human populations. The complicating factors include misdiagnosis due to the similarity of rickettsial-induced clinical signs to many commonly occurring infections and subsequent delayed treatment. Vigilance, preparedness, and the availability of efficacious vaccines and antibiotics are required to avert the morbidity and mortality and disturbances generated by the intentional release of pathogenic rickettsiae into large and immunologically naive human populations. This presentation reviews the rickettsial attributes that make them potential bioterrorism agents, as well as issues related to signs that would alert the responsible authorities, and the preventive measures that could reduce impact of these agents.

Animals↗
PubMedDate not supplied

Rickettsial pathogens and their arthropod vectors.

Rickettsial diseases, important causes of illness and death worldwide, exist primarily in endemic and enzootic foci that occasionally give rise to sporadic or seasonal outbreaks. Rickettsial pathogens are highly specialized for obligate intracellular survival in both the vertebrate host and the invertebrate vector. While studies often focus primarily on the vertebrate host, the arthropod vector is often more important in the natural maintenance of the pathogen. Consequently, coevolution of rickettsiae with arthropods is responsible for many features of the host-pathogen relationship that are unique among arthropod-borne diseases, including efficient pathogen replication, long-term maintenance of infection, and transstadial and transovarial transmission. This article examines the common features of the host-pathogen relationship and of the arthropod vectors of the typhus and spotted fever group rickettsiae.

Animals↗
PubMed2000

Canine rickettsial infections.

Dogs that live in tick-infested areas are at risk for contracting rickettsial infections. Clinical signs associated with ehrlichiosis or Rocky Mountain spotted fever may be dramatic or mild. Clinicians must consider the possibility of rickettsial diseases to request laboratory tests that will permit a proper diagnosis. Specific antimicrobial therapy usually brings about clinical improvement, although some dogs may not be cleared of rickettsial organisms, even with prolonged treatment. A small percentage of dogs die of rickettsial infections, either in the acute stage or owing to chronic bone marrow suppression and generalized debilitation. Ocular lesions are an important clinical sign in canine rickettsial infections and may aid the clinician in making a diagnosis and monitoring response to therapy.

Animals↗
PubMed1984

Macrophages in resistance to rickettsial infections: protection against lethal Rickettsia tsutsugamushi infections by treatment of mice with macrophage-activating agents.

Peritoneal macrophages of BALB/c and C3H/HeN mice activated in vivo by intraperitoneal inoculation of viable Mycobacterium bovis strain BCG or the nonliving macrophage-activating agent Propionibacterium acnes (Corynebacterium parvum), were resistant to infection with Rickettsia tsutsugamushi, and they killed bacteria that did gain entry into the intracellular environment of these cells. This macrophage resistance to infection and intracellular destruction of rickettsiae was dependent upon development of an immune response to the activating agents, since macrophages elicited by sterile inflammatory agents failed to display either microbicidal activity unless cells were exposed to factors present in lymphokine-rich culture fluids from antigen or mitogen stimulated spleen cells (LK) in vitro. C3H/HeN mice that had been treated with activating agents, but not sterile inflammatory irritants, also survived intraperitoneal inoculation of up to 10(4) R. tsutsugamushi. This nonspecific protection required the chronic presence of activated macrophages: acute immune response induced by intraperitoneal injection of PPD into mice inoculated intradermally with BCG, or intraperitoneal inoculation of conconavalin A, were not sufficient to induce survival of rickettsial disease, although macrophages from these animals were activated to kill rickettsiae at the time of challenge. The critical nature of activated macrophages in nonspecific protection against rickettsial infection was demonstrated with the macrophage-defective C3H/HeJ mice. These mice are equally as susceptible as C3H/HeN mice to intraperitoneal inoculation of R. tsutsugamushi, but do not develop activated macrophages in response to BCG infection, and are not protected against lethal rickettsial challenge following BCG treatment.

Animals↗
PubMed1999

Association of Rickettsia helvetica with chronic perimyocarditis in sudden cardiac death.

BACKGROUND: Rickettsia helvetica is the only non-imported rickettsia found in Scandinavia. It was first detected in Ixodes ricinus ticks, but has never been linked to human disease. We studied two young Swedish men who died of sudden cardiac failure during exercise, and who showed signs of perimyocarditis similar to those described in rickettsial disease. METHODS: Samples from the heart and other organs were analysed by PCR and DNA sequencing. May-Grünwald-Giemsa, Grocott, and acridine-orange stains were used for histopathological examinations. Staining of R. helvetica grown on shell-vials in vero cells, and the early descriptions of R. rickettsii by H T Ricketts and S B Wohlbach served as controls. Immunohistochemistry was done with Proteus OX-19 rabbit antisera as the primary antibody. The structure of rickettsia-like organisms was investigated by transmission electron microscopy. Serological analyses were carried out by indirect immunofluorescence with R. helvetica as the antigen. FINDINGS: By use of a semi-nested PCR, with primers specific for the 16S rRNA and 17-kDa outer-membrane-protein genes, and sequence analysis of the amplified products, genetic material from R. helvetica was detected in the pericardium and in a lymph node from the pulmonary hilum in case 1, and in a coronary artery and the heart muscle in case 2. A serological response in case 1 revealed an endpoint titre for R. helvetica of 1/320 (1/256 with R. rickettsii as the antigen). Examination of PCR-positive tissue showed chronic interstitial inflammation and the presence of rickettsia-like organisms predominantly located in the endothelium. These organisms reacted with Proteus OX-19 antisera, and their size and form were consistent with rickettsia. Electron microscopy confirmed that the appearance of the organisms was similar to that described for spotted-fever rickettsia. INTERPRETATION: R. helvetica, transmitted by I. ricinus ticks, may be an important pathogen in the aetiology of perimyocarditis, which can result in sudden unexpected cardiac death in young people.

Adult↗
PubMed1983

[Infectious arteriopathies].

After reviewing the physiopathology, the authors report the principal features of infectious arterial disease observed in a department of infectious diseases. Excluding iatrogenic arteritis, particularly after vascular surgery, and some vasculitis in which an infectious agent may play a role, only the classical but now rare causes are described: rickettsial disease, syphilis and typhoid. The most commonly observed problem at present is infectious aneurysms: primary aneurysms secondary to atherosclerosis in which salmonella is by far the predominant organism, before the staphylococci and streptococci. The most serious complication is the major risk of rupture which may be the presenting event. Secondary aneurysms are essentially those of endocarditis. The mechanism is not fully understood and they occur at different stages of the course of the disease. The main problem associated with these aneurysms is their multiplicity and localisation; the intracranial forms are the most common and most serious in the experience of the authors, with their difficulties of diagnosis and treatment: extracranial aneurysms are usually located in the main limb arteries. Adjacent secondary aneurysms are exceptionally rare. Tuberculous and viral causes of aneurysm are among the rarest etiologies discussed.

Adult↗
PubMed1990

Enzyme-linked immunosorbent assays for detecting antibody to Rickettsia australis in sera of various animal species.

New endemic areas of spotted fever-like rickettsial disease have been found in south-eastern Australia (Gippsland, Victoria and Flinders Island, Tasmania). The rickettsia responsible is currently unknown although it may be Rickettsia australis. To investigate serological evidence of rickettsial exposure in various wild animal species, a competitive ELISA was developed which detected antibodies to R. australis. It was based on inhibition of an indirect ELISA detecting antibody to R. australis in guinea pig sera. Pre- and post-infection sera from 2 dogs, 2 rabbits, 5 mice and 6 rats, experimentally infected with R. australis, were tested by competitive ELISA. The results showed that all pre-infection sera were negative and all post-infection sera positive for antibody to R. australis. To test the utility of the competitive ELISA for detecting natural rickettsial infection in non-laboratory animals, 51 dog sera, negative for rickettsial antibody by immunofluorescence (IF) and 20 IF positive dog sera (collected from various locations on the east coast of Australia) were tested. Compared to the IF test the competitive ELISA was 90% sensitive and 96% specific. This new test has potential for detecting antibody to R. australis in the sera of different wild animal species.

Animals↗
PubMed1993

Peripheral neuropathies after arthropod stings not due to Lyme disease: a report of five cases and review of the literature.

Five patients developed neurologic symptoms a few hours to 2 months after being stung by a non-hooking arthropod with immediate cutaneous reaction. The patients had no clinical or serologic evidence for Lyme borreliosis and rickettsial disease. Clinical and electrophysiologic findings were consistent with a mixed axonal and demyelinating mononeuropathy, a monomelic multiple mononeuropathy, a mononeuropathy multiplex, a radiculoneuritis, and a distal symmetric polyneuropathy. Muscle and nerve biopsies showed lymphoplasmacytic small-vessel vasculitis in all patients, and wallerian degeneration in three. These patients, and 17 others from the literature, indicate a spectrum of peripheral neuropathies occurring after insect and spider stings.

Adolescent↗
PubMed1996

Serological examination of human and animal sera from six countries of three continents for the presence of rickettsial antibodies.

Forty samples each of human sera collected in Guinea Bissau, Cape Verde, El Salvador and Iran, and animal sera (goat and cattle from Sri Lanka and sheep from Tanzania) were examined for the presence of antibodies to typhus group (TG) rickettsiae, spotted fever group (SFG) rickettsiae and Coxiella burnetii by enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody (IFA) test. Of human sera tested, a higher proportion of positive sera were found with ELISA and IFA test for TG, SFG rickettsiae and C. burnetii in El Salvador (42.5 vs 20.0%, 40.0 vs 32.5%, and 27.5 vs 27.5%, respectively) and in Iran (25.0 vs 15.0%, 45.0 vs 27.5%, and 27.5 vs 25.0%, respectively), than in Guinea Bissau and Cape Verde, where they were less than 20.0% except for antibodies to SFG rickettsiae in Guinea Bissau (25.0% with ELISA and 20.0% with IFA test). While all animal sera were negative for the presence of antibodies to TG rickettsiae, a high proportion of sera from Sri Lanka reacted in ELISA and IFA test with SFG rickettsiae and C. burnetii (37.5 vs 20.0% and 27.5 vs 25.0% for goat sera, and 40.0 vs 30.0%, and 17.5 vs 15.0% for cattle sera, respectively). The results obtained indicate that the studied rickettsial diseases can be spread in given territories and may pose a public health problem requiring greater attention than has been paid so far. The suitability of ELISA and IFA test for serological survey of rickettsial antibodies is discussed.

Animals↗
PubMed1992

Epidemiologic features and clinical presentation of acute Q fever in hospitalized patients: 323 French cases.

PURPOSE: To contribute to the knowledge of epidemiologic and clinical features of patients hospitalized with Q fever in France. METHODS: We conducted a retrospective analysis of 22,496 sera submitted between 1982 and 1990 to the French National Reference Center for Rickettsial Diseases (NRC). The diagnosis of acute Q fever was based on an IgG titer greater than or equal to 1:200 and an IgM titer greater than or equal to 1:25 against phase II Coxiella burnetii antigen on an indirect immunofluorescence test (IFA). Fifteen cases prior to 1985 were diagnosed on the basis of a complement fixation titer greater than or equal to 1:8. A serosurvey of blood donors from Marseille was also conducted in 1988 on 924 sera, using IFA with a cutoff titer of 1:25. RESULTS: The serosurvey conducted in 1988 showed a seroprevalence of 4.03%, without age or sex prediction. The incidence rate of acute Q fever detection at the NRC was 0.58 per 100,000 inhabitants over the 9-year period. Three hundred twenty-three clinical cases were diagnosed, rising from 1 in 1982 to 107 in 1990. In patients hospitalized for acute Q fever, there was a significantly higher sex ratio of males to females (2.3), which, coupled with the age distribution, indicated that elder males, who are overrepresented due to our recruitment bias, are more susceptible to C. burnetii infections. The mean age of the patients was 45.5 years, while the risk was increased in the 30 to 39 age group as well as in the 60 to 69 age group. Usual epidemiologic risk factors were found in 20.1% of the cases. Hepatitis (61.9%) was a more common clinical presentation in our patients with Q fever than pneumonia (45.8%). This might reflect differences in strains of C. burnetii or the biology of the host. However, French farmers and stock breeders commonly drink unpasteurized raw milk from their cattle, which might indicate a relationship between hepatitis and infection via the digestive tract. CONCLUSION: Our results indicate that many cases of acute Q fever are undiagnosed. A greater awareness of the disease and more extensive serologic testing of patients with symptoms compatible with Q fever may improve the situation.

Acute Disease↗
PubMed2003

Mediterranean spotted fever during pregnancy: case presentation and literature review.

Mediterranean spotted fever (MSF) is caused by Rickettsia conorii, an obligate intracellular parasite of eukaryotic cells. Although, usually this disease has a benign course, a rapidly fatal outcome can occur even in young healthy adults. We describe a case of a 40-year-old Bedouin woman gravida 11, para 10, who was admitted at 36 weeks gestation with this rickettsial disease. During pregnancy, the treatment of choice for Mediterranean spotted fever is chloramphenicol, but it seems that Azithromycin could be another possible option.

Adult↗
PubMed2006

Early diagnosis of rickettsioses by electrochemiluminscence.

The diagnosis of acute rickettsioses during the acute phase of the disease is challenging. We present preliminary evidence that antigen-capture using streptavidin-coated magnetic beads with biotinylated anti-rickettsia typhi rabbit polyclonal antibodies followed by electrochemiluminescent detection with ruthenylated antibodies of the same specificity could be used for the diagnosis of rickettsial diseases in the acute phase.

Animals↗