Enfermedades producidas por Rickettsia

Analysis of Rocky Mountain spotted fever cases in Northern Mexico reveals genetic variability of Rickettsia rickettsii and the different distribution of genotypes

Rickettsioses have been reported in parts of Mexico since the last century, with Rocky Mountain spotted fever (RMSF) being one of the most prevalent in northern states. Unfortunately, fatality rates for RMSF in Mexico are higher than in other countries, like the USA. The reason for this difference in fatality rates is currently unknown and could be associated with a genotype of the bacterium, but no comparative molecular typing has been conducted in Mexico to date. The purpose of this study was to analyze 47 RMSF samples with different outcomes from several states in northern Mexico to know the genetic variability of Rickettsia rickettsii, as well as to reconstruct its phylogeny, for which the following intergenic regions were sequenced: RR0155-rpmB, cspA-ksgA, RR1240-tlc5, and Spo0J-abc T1, as well as the following partial genes: ompA, ompB, and gltA. We identified 8 genotypes with different distribution and prevalence among the states analyzed, as well as a different association with case outcome; these genotypes were clustered in 2 clades and 5 lineages were revealed, some of them probably exclusive from Mexico.

Rickettsia conorii: Unusual case of acute aortic thrombosis

OBJECTIVES

Mediterranean spotted fever is a common zoonosis in Europe caused by Rickettsia conorii bacterium. Among its wide range of clinical presentations, arterial thrombosis of large vessels has never been described before.

METHODS

We report a case of a complete acute infrarenal aortic thrombosis in a 61-year-old male with R. conorii infection.

RESULTS AND CONCLUSION

The patient was successfully operated using open aortic surgery and subsequent treatment with doxycycline. To our knowledge, this is the first report of aortic thrombosis associated with infection by this parasite, extending the clinical spectrum of the disease.

Clinical and laboratory features of rickettsioses in Yucatan, Mexico

Rickettsia species are obligate intracellular bacteria that can cause mild to severe human disease. Based on phylogeny, clinical symptoms, and antigenic properties, rickettsiae are classified into four groups. Infections by these agents are characterized by clinical symptoms ranging from self-limited to severe and even fatal febrile illnesses, depending on the Rickettsia spp. involved, the patient's predisposition, and timely medical care. The present study aimed to characterize rickettsial diseases in Yucatan according to clinical and laboratory features appearing in medical records corresponding to 427 samples taken between 2015 and 2018. A study was conducted over the period 2015-2018 on 427 samples. Clinical and laboratory features were documented from the patients' medical records. For molecular diagnosis, blood was collected in 3.8 % sodium citrate as anticoagulant, and DNA was extracted. Single-step and nested PCR amplification was performed using genus-specific primers for the rickettsial 17kDa and ompB genes. The amplicons obtained were purified and sequenced. A total of 22.7 % (97/427) positive cases of Rickettsia spp. were identified by PCR from 14.15 % (15/106) of the municipalities in Yucatan. 75.2 % (73/97) of the cases were from the city of Merida during the autumn (September-December). The age groups with the highest frequency of confirmed cases were pediatric (5-14 years) (57.7 %) and adults (25-49 years) (42.2 %). There were six fatal cases in children, one associated with R. typhi and five with R. rickettsii. In non-fatal cases, 32.9 % (32/97) corresponded to the spotted fever group (SFG), and 60.8 % (59/97) to the typhus group (TG). Significant differences in signs, and laboratory data, were observed between the pediatric and adult populations. For the treatment of patients, oral and intravenous doxycycline was used in severe hospitalized cases. Typhus group and spotted fever group Rickettsiae are endemic pathological agents found in urban and rural areas of our region. Molecular identification allows for greater diagnostic accuracy and timely treatment and consequently a better prognosis. It is necessary to implement or reinforce measures focused on the dissemination of knowledge regarding rickettsial diseases and their prevention.

Molecular detection of Candidatus Rickettsia colombianensi in ticks (Acari, Ixodidae) collected from herpetofauna in San Juan de Carare, Colombia

Knowledge about ticks and Rickettsiae in Colombia is still limited and the areas of the country where studies have been conducted are scarce. In this study, ticks (Acari, Ixodidae) associated with reptiles and amphibians in San Juan de Carare, Santander department, were morphologically and molecularly identified and tested for the presence of Rickettsia. For the molecular characterization of ticks, CO1, 12S and 16S sequences were generated and compared with other sequences available in genbank. Our analyses confirmed that the collected ticks were Amblyomma dissimile, and we provide the first report of this species parasitizing the snake Leptodeira septentrionalis. Of the samples analyzed, 69% were positive for Rickettsia sp. using the gltA, ompA and sca1 genes. Rickettsia sequences generated in this study were also compared to sequences downloaded from genbank by Bayesian inference (BI) and maximum likelihood (ML) phylogenetic analyzes. The presence of a single Rickettsia species, Candidatus Rickettsia colombianensi, was identified. This study expands the knowledge regarding the distribution of A. dissimile ticks and Rickettsiae in Colombia.

Frequency of antibodies and seroconversion against Rickettsia spp in patients consulting health institutions in the department of Caldas, Colombia, 2016-2019

Introduction: Rickettsioses are zoonotic diseases transmitted by arthropods acting as vectors and reservoirs. Disease symptoms are nonspecific and, therefore, their clinical diagnosis is difficult. Indirect immunofluorescence (IFA) is the gold standard assay for diagnosis. The interest for conducting studies on these pathologies has resurfaced in Colombia since 2001; besides, previous studies have evidenced cases of rickettsiosis in the north of the department of Caldas. Objective: To establish the frequency of antibodies and seroconversion against Rickettsia spp. In patients consulting health institutions in Caldas, Colombia, from 2016 to 2019. Materials and methods: We conducted a quantitative, observational, and descriptive study on a non-probabilistic sample of 175 patients with symptoms compatible with rickettsiosis who consulted in different municipalities of Caldas, Colombia; IFA was performed to detect antibodies in the acute and convalescent phases against Rickettsia rickettsii, Rickettsia typhi, and Rickettsia felis. Results: The average age of the patients was 31 years. The municipalities with the highest proportion of seropositive cases were Belalcázar, Chinchiná, Filadelfia, La Dorada, La Merced, and Manizales; 66% of patients owned pets and 12% reported arthropod bites. The most frequent signs and symptoms were headache (69.7%), arthromyalgia (60%), and fever (58.2%). IgG seroprevalence was 60% for R. rickettsii, 47.9% for R. typhi, and, and 24% for R. felis. Eight patients presented seroconversion. Conclusion: We found evidence of the circulation of Rickettsia species from the spotted fever group and the typhus group associated with human cases in Caldas.

Spatial and temporal trends of Mediterranean spotted fever in Spain, 2005-2015

BACKGROUND

Mediterranean spotted fever (MSF) is a zoonotic disease caused by Rickettsia conorii and transmitted by Rhipicephalus sanguineus sensu lato. The aim of this study is to understand the epidemiology and trends regarding the disease in Spain, based on notifications to the Spanish National Epidemiology Surveillance Network (RENAVE) and the National Hospital Discharge Database (CMBD) between 2005 and 2015.

METHODS

We carried out a retrospective cross-sectional study of the cases and the outbreaks reported to the RENAVE and of those found in the CMBD between January 1^st, 2005 and December 31^st, 2015. We studied the characteristics of the cases and analyzed their spatio-temporal distribution.

RESULTS

1603 cases notified to the RENAVE and 1789 cases registered in the CMBD were analyzed. The most affected group were men between 45 and 64. There were 8 MSF outbreaks during the study period. RENAVE registered lower rates until 2012, when it was decided that MSF in Spain would become a notifiable disease. Across the temporal series we saw that there was seasonality with an increase in cases in summer, and an overall upward trend according to the RENAVE data and descending according to the CMBD. The geographic distribution was heterogeneous throughout the territory, with maximum rates in La Rioja at 1.87 cases and 2.01 cases per 100,000 inhabitants according to the RENAVE and the CMBD, respectively.

CONCLUSIONS

It is of great importance to continue monitoring the disease since it appears to be endemic throughout Spain. There is a need for a common strategy on monitoring and reporting, which would facilitate a more accurate picture on the MSF epidemiological scenario. Entomological information will be of added value.

Mediterranean spotted fever rickettsiosis in Italy, 2001-2015: Spatio-temporal distribution based on hospitalization records

The Mediterranean spotted fever (MSF) rickettsiosis is the predominant rickettsial disease among the spotted fever group (SFG) rickettsiae in the Mediterranean countries and North Africa. Its causative agent is Rickettsia conorii, although, SFG rickettsiosis - cases due to Rickettsia monacensis, Rickettsia massiliae and Rickettsia aeschlimannii were also described. A retrospective study based on hospital discharge records with a diagnosis of SFG rickettsiosis was carried out to describe the spatial pattern, the trend of the disease, and the epidemiological characteristics of persons hospitalized in the period 2001-2015. Standardized hospitalization ratios were calculated at municipal level using the European population. Smoothed maps were produced using a localised smoothing Poisson model. The mean annual standardized hospitalization rate was 1.36/100,000 person years (95%CI: 1.34; 1.39). Rates showed strong summer seasonality and tended to decrease over time. During the study period, 28.89% of municipalities had smoothed standardized hospitalization ratios greater than 1 and 14.01% above 20. Higher standardized hospitalization ratios were found in areas along the Tyrrhenian coast, especially in the south of Calabria and in the islands of Sardinia and Sicily, where the disease is of public health relevance.

Mediterranean spotted fever in Spain, 1997-2014: Epidemiological situation based on hospitalization records

Introduction

Mediterranean spotted fever (MSF) is a zoonotic disease caused by Rickettsia conorii. In Spain, deficiencies in the official reporting result in misreporting of this disease. This study aims to describe the clinical and temporal-spatial characteristics of MSF hospitalizations between 1997 and 2014.

Materials and methods

We performed a retrospective descriptive study using the Hospitalization Minimum Data Set (CMBD). All CMBD’s hospital discharges with ICD-9 CM code 082.1 were analyzed. Hospitalization rates were calculated and clinical characteristics were described. Spatial distribution of cases and their temporal behavior were also assessed.

Results

A total of 4,735 hospitalizations with MSF diagnosis were recorded during the study period, out of which 62.2% were male, mean age of 48. Diabetes mellitus, alcohol dependence syndrome, and chronic liver disease occurred in 10.8%, 2.4% and 2.8% hospitalizations, respectively. The median annual hospitalization rate showed a decreasing trend from a maximum of 12.9 in 1997 to a minimum rate of 3.1 in 2014. Most admissions occurred during the summer, showing a significant annual seasonal behavior. Important regional differences were found.

Discussion

Although MSF hospitalization rates have decreased considerably, it remains a public health problem due to its severity and economic impact. Therefore, it would be desirable to improve its oversight and surveillance.

[Rickettsiosis after tick bite: A subtle clinic picture on many occasions, we must be vigilant]

Rickettsia diseases are a group of tick-borne transmitted diseases, classified into 2 large groups: spotted fevers and typhus fevers. In addition, a new condition has been described recently, known as tick-borne lymphadenopathy. A retrospective series is presented of paediatric cases of rickettsia diseases diagnosed in 2013 and 2014. A total of 8 patients were included, of which 2 of them were diagnosed as Mediterranean spotted fever, and 6 as tick-borne lymphadenopathy. Rickettsia slovaca, Rickettsia sibirica mongolitimonae, and Rickettsia massiliae were identified in 3 of them. Aetiology, clinical features and treatment carried out in each of them are described. The interest of these cases is that, although most have a benign course, the high diagnostic suspicion and early treatment seem to be beneficial for its outcome.

Rickettsiae, protozoa, and opisthokonta/metazoa

Rhizobiales (formerly named Rickettsiales) cause in rare instances meningitis and meningovasculitis, respectively. In case of history of exposure, infection by Rhizobiales needs to be considered since both diagnosis and therapy may be extremely difficult and pathogen-specific. The same applies to protozoa; in this chapter, Babesia species, free-living amoebae and Entamoeba histolytica infection, including severe meningitis and brain abscess, infection by Trypanosoma species (South American and African trypanosomiasis) are discussed with respect to history, epidemiology, clinical signs, and symptoms as well as differential diagnosis and therapy. Parasitic flatworms and roundworms, potentially able to invade the central nervous system, trematodes (flukes), cestodes (in particular, Cysticercus cellulosae), but also nematodes (in particular, Strongyloides spp. in the immunocompromised) are of worldwide importance. In contrast, filarial worms, Toxocara spp., Trichinella spp., Gnathostoma and Angiostrongylus spp. are seen only in certain geographically confined areas. Even more regionally confined are infestations of the central nervous system by metazoa, in particular, tongue worms (=arthropods) or larvae of flies (=maggots). The aim of this chapter is (1) to alert the neurologist to these infections, and (2) to enable the attending emergency neurologist to take a knowledgeable history, with an emphasis on epidemiology, clinical signs, and symptoms as well as therapeutic management possibilities.

The changing etiology of fever of intermediate duration

BACKGROUND

Fever of intermediate duration (FID) is a common condition. Currently, its most frequent causes are not well defined.

METHODS

Prospective study of FID cases attended at a hospital in 2 periods: 1983-1989 and 2004-2005. Blood cultures and serologic studies for Brucella melitensis, Coxiella burnetii, Rickettsia typhi, Rickettsia conorii, cytomegalovirus, and Epstein-Barr virus were performed on all patients. Other microbiological, serological, radiological, or invasive procedures were performed according to clinician-in-charge criteria.

RESULTS

A total of 505 patients were included from 1983 to 1989, and 179 from 2004 to 2005. A diagnosis was reached in 410 (81.1%) and 109 patients (60.9%), respectively. The cause of FID was an infectious disease in 389 patients from the first period (94.8% of those with a final diagnosis) and 92 from the second (84.4%). Most were systemic infections, 328 (80%) in 1983-1989 and 74 (67.8%) in 2004-2005, followed by focal infections, 9.5% and 16.5%, respectively. Q fever was the most frequent etiology in both periods. In 2004-2005, brucellosis decreased and HIV infection emerged as a cause of FID. The origin of FID was non-infectious in 5.1% and 15.5%, respectively.

CONCLUSIONS

Q fever is the most frequent cause of FID in southern Spain. Studies over time are needed to identify changes in the etiologic spectrum of this condition. Important viral etiologies, such as HIV infection, may be detected as causes of FID. Further studies are needed to determine the importance of other agents as causes of FID.

Ixodes ricinus ticks are reservoir hosts for Rickettsia helvetica and potentially carry flea-borne Rickettsia species

BACKGROUND

Hard ticks have been identified as important vectors of rickettsiae causing the spotted fever syndrome. Tick-borne rickettsiae are considered to be emerging, but only limited data are available about their presence in Western Europe, their natural life cycle and their reservoir hosts. Ixodes ricinus, the most prevalent tick species, were collected and tested from different vegetation types and from potential reservoir hosts. In one biotope area, the annual and seasonal variability of rickettsiae infections of the different tick stages were determined for 9 years.

RESULTS

The DNA of the human pathogen R. conorii as well as R. helvetica, R. sp. IRS and R. bellii-like were found. Unexpectedly, the DNA of the highly pathogenic R. typhi and R. prowazekii and 4 other uncharacterized Rickettsia spp. related to the typhus group were also detected in I. ricinus. The presence of R. helvetica in fleas isolated from small rodents supported our hypothesis that cross-infection can occur under natural conditions, since R. typhi/prowazekii and R. helvetica as well as their vectors share rodents as reservoir hosts. In one biotope, the infection rate with R. helvetica was ~66% for 9 years, and was comparable between larvae, nymphs, and adults. Larvae caught by flagging generally have not yet taken a blood meal from a vertebrate host. The simplest explanation for the comparable prevalence of R. helvetica between the defined tick stages is, that R. helvetica is vertically transmitted through the next generation with high efficiency. The DNA of R. helvetica was also present in whole blood from mice, deer and wild boar.

CONCLUSION

Besides R. helvetica, unexpected rickettsiae are found in I. ricinus ticks. We propose that I. ricinus is a major reservoir host for R. helvetica, and that vertebrate hosts play important roles in the further geographical dispersion of rickettsiae.

Rickettsia slovaca infection in humans in the northeast of Spain: seroprevalence study

Catalonia is an endemic area of Mediterranean spotted fever. In 1997, A. Lakos described a new tick-borne infectious disease called tick-borne lymphadenopathy. The causative agent is Rickettsia slovaca, which is transmitted by Dermacentor marginatus ticks. We have diagnosed human cases in Catalonia. The objective of this study was to determinate seroprevalence of R. slovaca infection in humans in the northeast of Spain. The population included 217 subjects from Catalonia, northeast of Spain and was stratified by age and living place (rural, suburban, and urban). Age, gender, residence area, contact with animals, occupation, and history of rickettsioses was surveyed. Immunoglobulin G was measured by indirect immunofluorescence assay. Titers >or= 1/40 were considered. Seroprevalence of R. slovaca was 5.5% at titers of 1/40-1/320. Eight (3.7%) sera had antibodies against R. slovaca exclusively. Four sera reacted also against Rickettsia conorii and/or Bar29. Seroprevalence of R. slovaca would range from 3.7% to 5.5%. The only statistically significant association was that between R. slovaca seropositivity and age. We present serologic evidence of R. slovaca infection among population of Catalonia, northeast of Spain.

Tick-borne lymphadenopathy: a new infectious disease in children

OBJECTIVE

To describe the epidemiologic and clinical aspects of patients with tick-borne lymphadenopathy (TIBOLA).

PATIENTS AND METHODS

The study included all patients treated in our hospital who presented characteristic clinical signs of TIBOLA consisting in the presence of an inoculation lesion after a tick bite with regional lymphadenopathies. The study was carried out at the "Corporació Parc Taulí" hospital in the city of Sabadell, Barcelona, Spain. The inclusion period was from April 2000 to April 2006. Serology tests were performed for Rickettsia conorii, R. slovaca, and Borrelia burgdorferi. The presence of Rickettsia was assessed by means of polymerase chain reaction (PCR)-restriction fragment length polymorphism (PCR-RFLP) and linear-after-the exponential-PCR in blood, skin biopsy, and ticks from the patients.

RESULTS

Thirty-six patients fulfilled the inclusion criteria. Twenty-eight patients were children. In most cases, infection occurred between the months of October and April. In 34 patients the tick bite was on the scalp. A necrotic eschar surrounded by a perilesional erythematous halo was observed in 29 cases. All patients had painful regional lymphadenopathies. Serology for R. conorii was positive in 8 cases and for R. slovaca in 2. PCR was negative. The tick, identified as Dermacentor marginatus, was studied in 7 patients. Four of the 7 D. marginatus were positive for sequences compatible with R. slovoca as determined by RFLP or DNA sequencing. Thirty-three patients received antibiotic treatment. Progress was satisfactory in all cases.

CONCLUSIONS

TIBOLA is present in Catalonia (Northeastern Spain) mainly in children. Although clinical and epidemiologic manifestations are very specific microbiologic confirmation is difficult.

Rickettsia monacensis and human disease, Spain

We identified Rickettsia monacensis as a cause of acute tickborne rickettsiosis in 2 humans. Its pathogenic role was assessed by culture and detection of the organism in patients’ blood samples. This finding increases the number of recognized human rickettsial pathogens and expands the known geographic distribution of Mediterranean spotted fever–like cases.

Observed Prevalence of Tick-borne Pathogens in Domestic Animals in Sicily, Italy during 2003?2005

The objective of this study was to characterize the observed prevalence of tick-borne pathogens (TBP) in domestic animals in Sicily, Italy during 2003-2005. Serological (competitive ELISA and indirect immunofluorescence antibody, n = 3299) and DNA tests (polymerase chain reaction and reverse line blot, n = 2565) were conducted on horse, donkey, cattle, sheep, goat, pig and dog samples. Pathogens analysed included Anaplasma, Ehrlichia, Rickettsia, Babesia and Theileria species, and Coxiella burnetii. The most prevalent TBP were Anaplasma and Babesia species. The results reported herein suggested that cattle could serve as the major reservoir for Babesia and Theileria spp. while for Anaplasma spp. cattle, dogs, sheep and goats may be the most important reservoir species. These results expanded our knowledge about the prevalence of TBP in Sicily and provided information to understand the epidemiology of tick-borne diseases and may help to implement measures to diagnose, treat and control transmission to humans and animals in this region.

Low Incidence of Tick-Borne Rickettsiosis in a Spanish Mediterranean Area

The aim of this study was to know the incidence of tick-borne rickettsial disease in a Mediterranean area. The incidence in 5 years for 100,000 inhabitants was 1.7 for tick-borne-lymphadenopathy (TIBOLA) and 0.4 for Mediterranean spotted fever (MSF). MSH incidence during the last few years has been lower than expected; in contrast TIBOLA seems to be an emerging disease. At the present time our data suggest a low tick-borne rickettsiosis incidence of MSF and a superior incidence of TIBOLA than MSF in the Spanish Mediterranean area.