Extensive examination of different tick species for infestation with Coxiella burnetii in Slovakia

Between 1987–1989 almost 7000 adult Ixodes ricinus, Dermacentor reticulatus, Dermacentor marginatus, Haemaphysalis concinna, Haemaphysalis punctata and Haemaphysalis inermis ticks collected in all 38 districts of Slovakia were screened for the presence of Coxiella burnetii. The proportion of ticks containing C. burnetii as indicated by the haemocyte test was less than 3%. Attempts to recover C. burnetii by inoculation of yolk sacs of embryonated hen eggs from pools of 1–6 specimens of haemocyte test positive ticks resulted in the isolation of 10 rickettsial strains. Six strains were recovered from I. ricinus, the remaining ones from single pools of D. reticulatus, D. marginatus. H. concinna and H. inermis ticks.In addition to the previous recovery of C. burnetii from H. punctata ticks, the agent was thus isolated from all important ticks living in Slovakia. The agent was found in tick habitats regardless of the latitude and altitude in the entire country. These results are not consistent with the negligible number of Q fever cases occurring in past years in Slovakia.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Studies of a “new” rickettsiosis “Astrakhan” spotted fever

The acute febrile disease with characteristic rash seen in Astrakhan region and named as viral exanthema of unknown etiology was proved to be a spotted fever group rickettsiosis. Serological examination of humans from endemic areas by complement fixation test revealed antibodies to R. conorii, R. akari and strains Netsvetaev and AR-74 of R. sibirica in titres from 20 to 640 in sera from ill persons. Of 429 sera from healthy persons, 5.1% were serologically positive in a titre of 20–40. The presence of spotted fever group rickettsiae was detected in 8 of 104 Rhipicephalus sanguineus ticks removed from dogs and tested by haemocyte test with Gimenez staining and indirect immunofluorescence technique. Attempts at isolation of rickettsiae in guinea pigs and cell cultures resulted in appearance of specific spotted fever group rickettsiae antibodies in guinea pigs (4 of 8 samples examined were positive) and detection of rickettsiae by immunofluorescence technique in cell cultures (in 2 of 12 samples tested).Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990     

Isolation ofCoxiella burnetii and of an unknown rickettsial organism fromIxodes ricinus ticks collected in Austria

Two strains ofCoxiella burnetii and two strains of an unidentified rickettsial organism were isolated for the first time fromIxodes ricinus ticks collected in the Alpine region of Tirol, Austria. TheC. burnetii strains belong to the group of agents causing acute forms of Q fever. The other two strains of isolated rickettsial agent share some antigenic epitopes withC. burnetii andR. prowazekii but they differ from them by their high sensitivity to freezing and refreezing and by poor multiplication in yolk sacs of chick embryos. There is at present no evidence that these organisms cause human illness and no ecological information is available. We suggest they may be some new species of rickettsiae or rickettsia-like organisms.     

Seroepidemiology of rickettsial infections in Morocco

The prevalence of antibodies reactive withRickettsia conorii, Rickettsia typhi, Coxiella burnetii andEhrlichia chaffeensis was investigated using indirect immunofluorescence (IFA) test on human sera obtained from 300 blood donors in Casablanca and 126 sera obtained from clinical laboratories in Fez. In sera from Casablanca, antibodies reactive at titers >=1: 32 were found againstR. conorii (7%), andR. typhi (1.7%), but not againstE. chaffeensis. In the sera from Fez, antibodies were also detected againstR. conorii (5.6%),R. typhi (4%), but not againstE. chaffeensis. By Western immunoblotting, seroprevalence forR. conorii was in Casablanca and 4.8% in Fez. Antibodies reactive at titers >=1:50 againstC. burnetii (phase II) were present in sera from Casablanca (1%) and Fez (18.3%).Abbreviations IFA Immunofluorescence assay - MSF Mediterranean spotted fever - PBS Phosphate-buffered saline     

Boutonneuse fever in Portugal: 1995-2000. Data of a state laboratory

From 1995 through 2000, 3239 clinical samples were tested for rickettsiosis at the Center for Vectors and Infectious Diseases Research – National Health Institute in Portugal. Boutonneuse fever due to R. conorii Malish or R. conorii Israel was laboratory confirmed in 374 samples (11.5%). Clinical and epidemiological features are discussed.     

Serosurvey among Mediterranean spotted fever patients of a new spotted fever group rickettsial strain (Bar29)

Mediterranean spotted fever is an endemic disease in Catalonia, Spain. A new spotted fever group (SFG) rickettsial strain (Bar29) of unknown pathogenicity for humans was isolated by our group, in 1996, from the dog brown tick, Rhipicephalus sanguineus. Interestingly, Rickettsia conorii was not isolated in this study. The aim of the present study was to assess the possible pathogenic role of the Bar29 strain. To this purpose, serum samples from 15 patients with Mediterranean spotted fever were obtained and tested by immunofluorescence for antibodies against four related rickettsial strains (R. conorii, R. africae, R. massiliae, and Bar29). Eight of the studied sera reacted at high titers with only R. conorii and Bar29 antigens. For five of the eight sera, the titers against Bar29 were clearly higher than for R. conorii. Four of these sera were also studied by Western blot immunoassay to confirm a specific response. Two of these sera reacted with the high-molecular-mass specific proteins of Bar29 as well as with the low-molecular-mass region (LPS antigen) whereas their reactions with R. conorii were located only on bands of the LPS. This specific response would support the possible pathogenic role of the Bar29 strain for humans. According to this finding, spotted fever caused by R. conorii and rickettsial strain Bar29 may be present in our area. The epidemiological implications of spotted fever caused by R. conorii and by rickettsial strain Bar29 in the Catalonia deserve further studies with isolation and characterization of more rickettsial strains.     

Epidemiology of rickettsial diseases

Rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. For the spotted fever group (SFG) rickettsiae, Rickettsia typhi. R. tsutsugamushi, Coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. All rickettsioses exist as zoonoses. Moreover, all rickettsiae are found in infected arthopods, which generally serve as the natural hosts and can transmit the infection to the next generation of ticks, mites, chiggers, or fleas. From our anthropocentric viewpoint, Q fever aerosol infection from parturient animals and Brill-Zinsser disease ignited epidemics of louse-borne epidemic typhus are exceptions. However, silent cycles of C. burnetii in ticks and R. prowazekii in the flying squirrel flea may have maintained these agents in transovarial or enzootic cycles for eons before humans and their domestic animals arrived on the scene. Thus, the epidemiology of rickettsial diseases must be recognized as an unfortunate aberration of the rickettsial economy.Several excellent reviews of rickettsial ecology contain a wealth of useful information (2, 8, 55, 70, 84).Presented at the 4th International Symposium on Riskettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Evidence of the presence of spotted fever group rickettsiae in dogs and dog ticks of the central provinces in Spain

To assess canine exposure to spotted group rickettsiae in the central provinces of Spain, ticks removed from dogs were studied by immunofluorescence (IF) staining. Twenty-eight out of 65 (43.0%) samples from ticks were positive. Sera from 58 dogs were also collected and the presence of antibodies to Rickettsia conorii studied. Thirty-four (58.6%) dogs presented significant titers by IF. Surveillance data from these provinces show the presence of Boutonneuse fever cases during recent years, evidence that dogs could serve as an indicator of rickettsial activity in these areas.Corresponding author.     

Urban family cluster of spotted fever rickettsiosis linked to Rhipicephalus sanguineus infected with Rickettsia conorii subsp. caspia and Rickettsia massiliae

Here, we report an epidemiological and entomological investigation of a cluster of cases of spotted fever group (SFG) rickettsiosis occurring in southern France. A family of 3 (husband, wife, and their son) presented with symptoms compatible with SFG rickettsiosis. For 2 patients, serum samples presented increased levels of IgM and IgG for SFG Rickettsia. The patients’ home was investigated, and Rhipicephalus sanguineus ticks were collected from the floor from behind the furniture. Of 22 ticks collected, 20 tested positive for Rickettsia. As Rh. sanguineus serves as a vector for both Rickettsia conorii and Ri. massiliae in southern France, all Rh. sanguineus isolates were tested by real-time PCR and conventional PCR to detect the 2 species. Nine ticks tested positive for Ri. conorii subsp. caspia (marking the first documentation of this subspecies in France), 7 tested positive for Ri. massiliae, and 4 tested positive for both rickettsiae. This study is the first report of coinfection of Rh. sanguineus ticks with Ri. conorii and Ri. massiliae in southern France.     

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 burnetii, phase II, and Rickettsia typhi antigens. Titers 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. burnetii, phase II, was detected in 50.2% of sera. These positive cases were related to rural environmental factors and to prevoius 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 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.     

Lack of co-transmission of Rickettsia conorii and Ehrlichia canis in human beings in the south of France

Ehrlichia canis is the agent of canine Ehrlichiosis, commonly known as canine tropical pancytopenia. This canine disease is frequent in our area, as is Mediterranean Spotted Fever in humans. Recently a few cases of human Ehrlichiosis have been described in the USA. The supposed vector of both diseases is Rhipicephalus sanguineus. In order to evaluate the cotransmission of these two diseases, we selected 498 human sera positive for R. conorii and tested them for Ehrlichia canis. None of them were positive, suggesting the lack of co-transmission of the diseases.Corresponding author.     

First detection of Rickettsia aeschlimannii in Hyalomma dromedarii ticks from Tunisia

Tick-borne rickettsioses have long been described in North Africa. These human diseases and their causative agents occur in several countries in this region, including Mauritania, Morocco, Algeria, Tunisia, Libya, and Egypt. In Tunisia, the first described and most well-known rickettsiosis is Mediterranean spotted fever, which is caused by Rickettsia conorii conorii. Cases of R. aeschlimannii infections have been documented by serology, but the agent has never actually been detected in patients or arthropods in the country. In October 2008, ticks were collected from a dromedary (Camelius dromedarii) in Douz, Central Tunisia. All of the ticks were identified as Hyalomma dromedarii and were tested using polymerase chain reaction to determine the presence of rickettsiae. Our results indicate the first molecular detection of R. aeschlimannii in ticks from Tunisia.     

Antibodies to spotted fever group rickettsiae in dogs in Croatia

The prevalence of IgG antibodies to spotted fever group rickettsiae was studied by the indirect immunofluorescent antibody assay in a sample of 194 canine sera from different parts of Croatia. Dogs (n=141) from urban and suburban-semirural environs from the middle part of the eastern coast of Adriatic sea, and dogs (n=53) from Zagreb, the capital of Croatia located in the northern continental part of Croatia, were tested. The total of 88 (62.4%) dogs from southern coastal Croatia had antibodies toRickettsia conorii, with a significantly higher prevalence (69.9%) in suburban-semirural areas. The prevalence rate of antibodies toRickettsia conorii in canine sera from urban environment in the north of Croatia was 20.7%. The results show that the members of spotted fever group rickettsiae are present in both coastal and continental Croatia.Abbreviations IFA indirect immunofluorescence - IgG immunoglobulin G - MSF Mediterranean spotted fever - SFG spotted fever group     

Mediterranean spotted fever: A preliminary tick field study

We studied the prevalence of rickettsia-like organisms infection in different tick species (3154 adults) collected in several areas of the Ebro valley (Spain). The Gimenez stain showed a prevalence of rickettsia-like organisms in 38.6% of the studied ticks. Using the immunofluorescence assay, only two species, Rhipicephalus sanguineus (16.4%) and R. pusillus (19.9%) have shown organisms compatible with spotted fever group rickettsiae.     

Rickettsioses studies. 3. Natural foci of rickettsioses in south Bohemia.

Antibodies against Coxiella burnetii and against rickettsiae of the spotted fever group were found in human sera and in sera from domestic and wild animals collected in south Bohemia. Spotted fever group rickettsiae were also discovered in the tick Ixodes ricinus. These results indicate the presence of both types of rickettsiae in this part of Czechoslovakia. As no epizootics or epidemics of Q fever have as yet been reported in the area, it can be assumed that C. burnetii occurs in the latent state. The occurrence of spotted fever group rickettsiae is probably endemic among I. ricinus ticks and among small and larger wild mammals.     

High incidence of Coxiella burnetii markers in a rural population in France

Since Coxiella burnetii, the causative agent of Q fever, is often transmitted from goats and sheep to humans through aerosols, we examined the sera from 168 persons involved in goat breeding in the Centre region of France and 40 members of veterinary and medical staff from the same region for the presence of antibodies against C. burnetii. An immunofluorescence assay was used to detect the presence of antibodies of the IgG isotope against epitopes from phase II of C. burnetii, which are the first antibodies to appear in infected people, and from phase I, which reflect more chronic stages of the infection. Our serological survey showed that most of the tested sera were positive for C. burnetii markers, indicating at least an encounter with the bacterium. In the overall population of 208 subjects, 71% of the sera had antibodies against phase II epitopes (titres 1:40). Among the goat farmers and their immediate families, 78% had antibodies against phase II and 33% against phase I (titres 1:40). Considering only high titres ( 1:320), though, only 37% of the farmers had antibodies against phase II and 15% against phase 1. Only 3 out of 12 veterinarians working in the field had high titres of antibodies against phase II and phase I, while none of 28 members of veterinary and medical laboratories had significant levels of antibodies. These results emphasize the need for closer surveillance of populations at risk for Q fever, to prevent the infection by C. burnetii from reaching chronic stages of the disease.     

Serologic response to rickettsial antigens in patients with Astrakhan fever

Astrakhan fever is a new spotted fever group (SFG) rickettsiosis. Sera of patients with Astrakhan fever have been examined by microimmunofluorescense and western immunoblotting to determine the serologic responses to the Astrakhan strain and toR. conorii M-1 strain and the Israelian isolate of SFG rickettsiae. The serologic response to specific rickettsial agent and to Israelian isolate has been found to be similar, but was different of that toR. conorii. Immunoglobulin G (IgG) and IgM antibodies were detected in most sera and were directed against the lipopolysaccharide. Only one of tested sera contained IgG antibodies which also recognized high molecular weight proteins.     

Ricettsioses studies. 2. Natural foci of rickettsioses in east Slovakia.

Natural foci of Q fever and of spotted fever group rickettsiae in the Košice district of east Slovakia are described and discussed. It was established that the natural focus of Q fever was a secondary one. Cattle were observed to be the main source of human infection and a high proportion of synanthropic rodents was found to be infested with Coxiella burnetii. The natural focus of spotted fever group rickettsiae was shown to be of a primary character, such rickettsiae circulating among ticks and small mammals. It is suggested that natural foci of spotted fever group rickettsiae in east Slovakia may be connected with the natural distribution of Dermacentor ticks.     

Transmission of antibodies to Chlamydia Psittaci and Coxiella Burnetii through eggs and “crop milk” in pigeons

Young semi-domesticated pigeons captured or hatched from eggs gathered in Bratislava during 1989–1991 were examined for complement fixing antibodies to Chlamydia psittaci and agglutinating antibodies to Coxiella burnetii. Antibodies to Ch. psittaci were present in 76% of birds younger than 24 h, in 47.7% between 1 and 10 days of age and in 12% of nestlings over 10 days old. Antibodies to Ch. psittaci were also detected in crop milk of 4.1% of 1 to 10 day old birds and in 4.5% of specimens older than 10 days. Antibodies to C. burnetii were not found in juvenile birds under 24 h old, but antibodies against this agent were present in 16.4% birds between 1 and 10 days old and in 18% over 10 days old. Antibodies to C. burnetii were also detected in crop milk collected from crops of 2% of the young birds between 1 and 10 days.     

Prevalence of Coxiella burnetii and Rickettsia spp. in ticks and rodents in southern Germany

Coxiella burnetii, the causative agent of Q fever, and Rickettsia spp. are bacterial pathogens that can be transmitted by ticks of the genus Dermacentor (i.e., Dermacentor marginatus and D. reticulatus). In Germany, the occurrence of these ticks is currently limited to few areas. However, due to increasing temperatures, these vectors will likely extend their distribution in the future, and C. burnetii and Rickettsia spp. might spread with them. To assess the prospective risk of human infections by these agents, it is important to know their current distribution. We collected 666 adult Dermacentor spp. and 119 rodents, mainly Microtus arvalis, in 3 Q fever endemic areas in southern Germany. Ticks and rodent organ pools were screened by PCR for C. burnetii and Rickettsia spp. No evidence of C. burnetii infections could be found in ticks or rodents, suggesting that these animals do not play an essential role in the epidemiology of Q fever in Germany. Rickettsia raoultii and R. slovaca could be detected in 30.3% and 0.75% of all examined ticks, respectively. In contrast, no rickettsia infections could be found in any rodent samples. Both rickettsia species can cause tick-borne lymphadenopathy (TIBOLA), a usually mild human disease. Because of the possible transmission of these rickettsiae to humans, TIBOLA should be considered in the differential diagnosis of tick-borne diseases. Our data show that a spread of these rickettsiae is possible in Germany and that more studies on the distribution of these agents are necessary.