Seroprevalence of viral and vector-borne bacterial pathogens in domestic dogs (Canis familiaris) in northern Botswana.

BACKGROUND: Domestic dogs (Canis familiaris) have the potential to act as disease reservoirs for wildlife and are important sentinels for common circulating pathogens. Therefore, the infectious disease seroprevalence among domestic dogs in northern Botswana may be indicative of pathogen exposure of various wildlife species. The objective of this study was to assess the seroprevalence of Ehrlichia spp., Borrelia burgdorferi, Anaplasma spp., Dirofilaria immitis, canine adenovirus, canine parvovirus, and canine distemper virus in domestic dogs as proxies of disease prevalence in the local wildlife in the Okavango Delta region of Botswana. Statistical analysis assessed crude and factor-specific seroprevalence proportions in relation to age, sex, and geographical location as predictors of seropositivity. Logistic regression was used to identify adjusted predictors of seropositivity for each of the pathogens of interest. RESULTS: Samples from 233 dogs in a total of seven locations in Maun, Botswana, and surrounding villages were collected and serologically analyzed. No dogs were seropositive for B. burgdorferi, while low seroprevalence proportions were observed for Anaplasma spp. (2.2%) and D. immitis (0.9%). Higher seroprevalence proportions were observed for the tick-borne pathogen Ehrlichia spp. (21.0%), and 19.7% were seropositive for canine adenovirus (hepatitis). The highest seroprevalence proportions were for canine parvovirus (70.0%) and canine distemper virus (44.8%). The predictors of seropositivity revealed that adults were more likely to be seropositive for canine adenovirus, canine distemper virus, and canine parvovirus than juveniles, and location was a risk factor for canine adenovirus, canine distemper virus, canine parvovirus, and Ehrlichia spp. CONCLUSIONS: Results indicate that increasing tick control and vaccination campaigns for domestic dogs may improve the health of domestic animals, and potentially wildlife and humans in the Okavango Delta since viral and vector-borne bacterial pathogens can be transmitted between them.

Characterization of tick organic anion transporting polypeptides (OATPs) upon bacterial and viral infections.

BACKGROUND: Ixodes scapularis organic anion transporting polypeptides (OATPs) play important roles in tick-rickettsial pathogen interactions. In this report, we characterized the role of these conserved molecules in ticks infected with either Lyme disease agent Borrelia burgdorferi or tick-borne Langat virus (LGTV), a pathogen closely related to tick-borne encephalitis virus (TBEV). RESULTS: Quantitative real-time polymerase chain reaction analysis revealed no significant changes in oatps gene expression upon infection with B. burgdorferi in unfed ticks. Synchronous infection of unfed nymphal ticks with LGTV in vitro revealed no significant changes in oatps gene expression. However, expression of specific oatps was significantly downregulated upon LGTV infection of tick cells in vitro. Treatment of tick cells with OATP inhibitor significantly reduced LGTV loads, kynurenine amino transferase (kat), a gene involved in the production of tryptophan metabolite xanthurenic acid (XA), levels and expression of several oatps in tick cells. Furthermore, bioinformatics characterization of OATPs from some of the medically important vectors including ticks, mosquitoes and lice revealed the presence of several glycosylation, phosphorylation and myristoylation sites. CONCLUSIONS: This study provides additional evidence on the role of arthropod OATPs in vector-intracellular pathogen interactions.

Analysis of the effect of temperature on protein abundance in Demodex-associated Bacillus oleronius.

A potential role for bacteria in the induction of rosacea has been suggested. The aim of this work was to characterise the effect of temperature on the production of immunostimulatory proteins by Bacillus oleronius-a bacterium to which rosacea patients show sera reactivity and which was originally isolated from a Demodex mite from a rosacea patient. The affected skin of rosacea patients is at a higher temperature than unaffected skin, and it was postulated that this might alter the protein expression pattern of B. oleronius. B. oleronius growth was reduced at 37°C compared to 30°C but resulted in increased expression of the immune-reactive 62kDa protein (1.65 fold [P < 0.05]). Proteomic analysis revealed increased abundance of a wide range of proteins involved in the stress response (e.g. stress proteins [21.7-fold increase], phosphocarrier protein HPr [438.5-fold increase], 60 kDa chaperonin [12.6-fold increase]). Proteins decreased in abundance after growth at 37°C included ferredoxin (325-fold decrease) and peptidase (244-fold decrease). This work indicates that the increased skin temperature of rosacea patients may alter the growth and protein production pattern of B. oleronius and lead to the greater production of immuo-stimulatory proteins.

Amblyomma triste en simpatría con Amblyomma tigrinum (Acari: Ixodidae) en la provincia de Santa Fe, Argentina / Amblyomma triste and Amblyomma tigrinum (Acari: Ixodidae) in sympatry in Santa Fe Province, Argentina

El objetivo del presente trabajo es comunicar el hallazgo de Amblyomma triste por primera vez en la provincia de Santa Fe, Argentina, y sumar una nueva localidad para Amblyomma tigrinum en la misma provincia. Ambas especies de garrapatas son reconocidos vectores de Rickettsia parkeri, agente etiológico de la fiebre manchada. Los especímenes fueron colectados durante el mes de agosto de 2014 y diciembre de 2015 a partir de turistas en la Fundación Federico Wildermuth (31° 59'S, 61° 24'O), departamento de San Martín, provincia de Santa Fe. Se colectaron 5 garrapatas adultas que fueron identificadas morfológicamente como A. tigrinum (3 hembras y 1 macho) y A. triste (1 hembra). El presente hallazgo de A. triste y A. tigrinum representa el primero en incluir a ambas especies del complejo Amblyomma maculatum en una misma localidad y permite alertar sobre la presencia de vectores de R. parkeri en la zona. Nuevos estudios que incluyan el muestreo de un mayor número de garrapatas y la detección de R. parkeri permitirán dilucidar más aspectos sobre la situación de esta rickettsia en Santa Fe.

The aim of this communication is to report, for the first time, the occurrence of Amblyomma triste in Santa Fe province, Argentina, and to add a new isolation place for Amblyomma tigrinum. Both species of ticks are vectors of Rickettsia parkeri, a spotted fever group rickettsia. Ticks were recovered from tourists in August 2014 and December 2015 at the Federico Wildermuth Foundation (31° 59'S, 61° 24'O), San Martin Department, Santa Fe province. Five adult ticks were morphologically identified as A. tigrinum (3 females and 1 male) and A. triste (1 female). This is the first finding including both Amblyomma maculatum group species, A. triste and A. tigrinum, together in the same locality in Argentina. This finding suggests that this site might have favorable features for the development of both species of R. parkeri vector. Further studies including sampling of a larger number of ticks and detection of R. parkeri DNA are needed to better document the epidemiology of this rickettsia in Santa Fe.

Vector competence of the blacklegged tick, Ixodes scapularis, for the recently recognized Lyme borreliosis spirochete Candidatus Borrelia mayonii.

A novel species within the Borrelia burgdorferi sensu lato complex, provisionally named Borrelia mayonii, was recently found to be associated with Lyme borreliosis in the Upper Midwest of the United States. Moreover, B. mayonii was detected from host-seeking Ixodes scapularis, the primary vector of B. burgdorferi sensu stricto in the eastern United States. We therefore conducted a study to confirm the experimental vector competence of I. scapularis for B. mayonii (strain MN14-1420), using colony ticks originating from adults collected in Connecticut and CD-1 white mice. Larvae fed on mice 10 weeks after needle-inoculation with B. mayonii acquired spirochetes and maintained infection through the nymphal stage at an average rate of 12.9%. In a transmission experiment, 40% of naïve mice exposed to a single infected nymph developed viable infections, as compared with 87% of mice fed upon by 2-3 infected nymphs. Transmission of B. mayonii by one or more feeding infected nymphs was uncommon up to 48h after attachment (one of six mice developed viable infection) but occurred frequently when nymphs were allowed to remain attached for 72-96h or feed to completion (11 of 16 mice developed viable infection). Mice infected via tick bite maintained viable infection with B. mayonii, as determined by ear biopsy culture, for at least 28 weeks. Our results demonstrate that I. scapularis is capable of serving as a vector of B. mayonii. This finding, together with data showing that field-collected I. scapularis are infected with B. mayonii, indicate that I. scapularis likely is a primary vector to humans of this recently recognized Lyme borreliosis spirochete.

The Borrelia burgdorferi RelA/SpoT Homolog and Stringent Response Regulate Survival in the Tick Vector and Global Gene Expression during Starvation.

As the Lyme disease bacterium Borrelia burgdorferi traverses its enzootic cycle, alternating between a tick vector and a vertebrate host, the spirochete must adapt and persist in the tick midgut under prolonged nutrient stress between blood meals. In this study, we examined the role of the stringent response in tick persistence and in regulation of gene expression during nutrient limitation. Nutritionally starving B. burgdorferi in vitro increased the levels of guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), collectively referred to as (p)ppGpp, products of the bifunctional synthetase/hydrolase RelBbu (RelA/SpoT homolog). Conversely, returning B. burgdorferi to a nutrient-rich medium decreased (p)ppGpp levels. B. burgdorferi survival in ticks between the larval and nymph blood meals, and during starvation in vitro, was dependent on RelBbu. Furthermore, normal morphological conversion from a flat-wave shape to a condensed round body (RB) form during starvation was dependent on RelBbu; relBbu mutants more frequently formed RBs, but their membranes were compromised. By differential RNA sequencing analyses, we found that RelBbu regulates an extensive transcriptome, both dependent and independent of nutrient stress. The RelBbu regulon includes the glp operon, which is important for glycerol utilization and persistence in the tick, virulence factors and the late phage operon of the 32-kb circular plasmid (cp32) family. In summary, our data suggest that RelBbu globally modulates transcription in response to nutrient stress by increasing (p)ppGpp levels to facilitate B. burgdorferi persistence in the tick.

Ehrlichia chaffeensis infection in the reservoir host (white-tailed deer) and in an incidental host (dog) is impacted by its prior growth in macrophage and tick cell environments.

Ehrlichia chaffeensis, transmitted from Amblyomma americanum ticks, causes human monocytic ehrlichiosis. It also infects white-tailed deer, dogs and several other vertebrates. Deer are its reservoir hosts, while humans and dogs are incidental hosts. E. chaffeensis protein expression is influenced by its growth in macrophages and tick cells. We report here infection progression in deer or dogs infected intravenously with macrophage- or tick cell-grown E. chaffeensis or by tick transmission in deer. Deer and dogs developed mild fever and persistent rickettsemia; the infection was detected more frequently in the blood of infected animals with macrophage inoculum compared to tick cell inoculum or tick transmission. Tick cell inoculum and tick transmission caused a drop in tick infection acquisition rates compared to infection rates in ticks fed on deer receiving macrophage inoculum. Independent of deer or dogs, IgG antibody response was higher in animals receiving macrophage inoculum against macrophage-derived Ehrlichia antigens, while it was significantly lower in the same animals against tick cell-derived Ehrlichia antigens. Deer infected with tick cell inoculum and tick transmission caused a higher antibody response to tick cell cultured bacterial antigens compared to the antibody response for macrophage cultured antigens for the same animals. The data demonstrate that the host cell-specific E. chaffeensis protein expression influences rickettsemia in a host and its acquisition by ticks. The data also reveal that tick cell-derived inoculum is similar to tick transmission with reduced rickettsemia, IgG response and tick acquisition of E. chaffeensis.

Guías Latinoamericanas de la RIICER para el diagnóstico de las rickettsiosis transmitidas por garrapatas / Latinamerican guidelines of RIICER for diagnosis of tick-borne rickettsioses

Tick-borne rickettsioses are worldwide infectious diseases that are considered emerging and re-emerging. Until recently the only tick-borne rickettsiosis present in Latin America was Rickettsia rickettsii infection, but to date, with the incorporation of new tools as PCR and sequencing and the quick cellular close tube cultures (Shell-vial), new species has been involved as human pathogens. In these guidelines, we offer an update of the microbiological assays for diagnosing rickettsioses. Besides we have included a section in which the most important hard ticks involved in human rickettsioses in Latinoamerica are detailed.

Las rickettsiosis transmitidas por garrapatas son afecciones de distribución mundial, que por diferentes motivos se pueden considerar emergentes y reemergentes. Hasta hace escasos años la única rickettsiosis transmitida por garrapatas en Latinoamérica era la infección por Rickettsia rickettsii, pero en la actualidad y fundamentalmente, gracias a la incorporación de nuevas herramientas para el diagnóstico microbiológico como la reacción en cadena de la polimerasa y secuenciación o el cultivo celular rápido en tubo cerrado, se han descrito e involucrado otras especies de Rickettsia en la producción de patología humana. En estas guías se detallan y describen las diferentes técnicas utilizadas para el diagnóstico microbiológico de las rickettsiosis. Además, se incluye una sección en la que se detallan las especies más importantes de garrapatas duras relacionadas con las rickettsiosis en Latinoamérica, con claves para su clasificación taxonómica.

Molecular detection of avian pathogens in poultry red mite (Dermanyssus gallinae) collected in chicken farms.

Poultry red mite (PRM, Dermanyssus gallinae) is a blood-sucking ectoparasite as well as a possible vector of several avian pathogens. In this study, to define the role of PRM in the prevalence of avian infectious agents, we used polymerase chain reaction (PCR) to check for the presence of seven pathogens: Avipox virus (APV), Fowl Adenovirus (FAdV), Marek's disease virus (MDV), Erysipelothrix rhusiopathiae (ER), Salmonella enterica (SE), Mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG). A total of 159 PRM samples collected between 2004 and 2012 from 142 chicken farms in 38 prefectures in Japan were examined. APV DNA was detected in 22 samples (13.8%), 19 of which were wild-type APV. 16S ribosomal RNA (16S rRNA) of MS was detected in 15 samples (9.4%), and the mgc2 gene of MG was detected in 2 samples (1.3%). Eight of 15 MS 16S rRNA sequences differed from the vaccine sequence, indicating they were wild-type strains, while both of the MG mgc2 gene sequences detected were identical to the vaccine sequences. Of these avian pathogen-positive mite samples, three were positive for both wild-types of APV and MS. On the other hand, the DNAs of ER, SE, FAdV and MDV were not detected in any samples. These findings indicated that PRM can harbor the wild-type pathogens and might play a role as a vector in spreading these diseases in farms.

[Update on SENLAT syndrome: scalp eschar and neck lymph adenopathy after a tick bite]. / Les nouveautés sur le syndrome SENLAT : Scalp Eschar and Neck LymphAdenopathy after Tick bite.

SENLAT syndrome, also known as TIBOLA/DEBONEL, is an emerging disease in France. The major symptoms are necrotic eschar on the scalp associated with painful cervical lymphadenopathy. It occurs mainly in women and children during the cold seasons after a bite by a Dermacentor tick, responsible for transmitting Rickettsia slovaca or Rickettsia raoultii. Cutaneous swabs are safe, easy and reliable tools that should be used routinely by physicians to confirm diagnosis. In this particular disease, they should be preferred to serology, which is less sensitive. Doxycycline is the antibiotic of choice for this syndrome.

Serologic evidence of human Rickettsia infection found in three locations in Panamá / Evidencia serológica de infecciones de Rickettsia en humanos provenientes de tres localidades de Panamá

Introduction: Since the middle of last century, cases of rickettsiosis have been found in Panamá when outbreaks of murine typhus and spotted fever were reported. Since then, little information exists about its prevalence in this country, since it is most often is misdiagnosed as another disease. Objectives: The aim of this paper is to demonstrate the presence of Rickettsia infections in humans in three locations in Panamá. These locations are agricultural areas, near forested areas or those who work in zoo. Materials and methods: Three locations where chosen for this study: Tortí, El Valle de Antón and workers in the Summit Municipal Park in Panamá City. All volunteers signed an informed consent and answered a questionnaire. The samples were analyzed for the detection of rickettsial spotted fever and typhus group by the indirect immunofluorescence (using commercial kits) and antigens of Rickettsia rickettsii and R. amblyommii. Results: Blood samples were taken from 97 volunteers in Tortí (25), El Valle de Anton (37) and Summit Municipal Park (35). Of these, a total of 38 (39%) samples reacted to one of the two methods: eight (32%) in Tortí, 18 (48%) in El valle and 12 (34%) in Summit Municipal Park. Conclusion: The results show a high prevalence of antibodies to Rickettsia belonging to the spotted fever group in each of the three study areas, in addition to presenting evidence of the typhus group Rickettsia in El Valle de Anton. These areas could be considered endemic for rickettsiosis as there are conditions for maintaining them.

Introducción. Desde mediados del siglo pasado, se conocen en Panamá casos de rickettsiosis, cuando fueron reportados brotes de tifus en ratones y de fiebres manchadas. A partir de entonces, poca información se tiene sobre su prevalencia en este país, lo cual se debe principalmente a que son confundidos con otras enfermedades. Objetivos. El objetivo de este trabajo fue demostrar la presencia de rickettsiosis en humanos provenientes de tres localidades de Panamá, que corresponden a zonas agropecuarias, cercanas a bosques, o que trabajaban en zoológicos. Materiales y métodos. Se escogieron tres localidades para este estudio: Tortí (provincia de Panamá), El Valle de Antón (provincia de Coclé) y el Parque Municipal Summit en Ciudad de Panamá. Los voluntarios firmaron un consentimiento informado, además de responder un cuestionario. De cada voluntario se extrajo sangre venosa, la que fue analizada por medio de inmunoflorescencia indirecta, utilizando kits comerciales y láminas sensibilizadas con antígenos cultivados de Rickettsia rickettsii y Rickettsia amblyommii . Resultados. Se tomaron muestras de 97 voluntarios, 25 en Tortí, 37 en El Valle de Antón y 35 en el Parque Municipal Summit. De estos, 38 (39 %) de las muestras fueron positivas en algunas de las dos técnicas practicadas: 8 (32 %) en Tortí, 18 (48 %) en El Valle y 12 (34 %) en el Parque Municipal Summit. Conclusión. Se demuestra una alta prevalencia de anticuerpos contra Rickettsia del grupo de las fiebres manchadas en las tres áreas de estudio, además de presentarse evidencia de títulos para Rickettsia del grupo tifus en El Valle de Antón. Estas zonas podrían considerarse como endémicas por rickettsiosis, ya que existen condiciones que permiten el mantenimiento de las mismas.

Ecoepidemiología de la infección por rickettsias en roedores, ectoparásitos y humanos en el noroeste de Antioquia, Colombia / Ecoepidemiology of rickettsial infection in rodents, ectoparasites and humans in northeastern Antioquia, Colombia

Introducción. Las rickettsias son bacterias patógenas usualmente transmitidas por ectoparásitos, como garrapatas, piojos o pulgas. En la última década se presentaron tres brotes de rickettsiosis con casos fatales en la región noroccidental de Antioquia y en un municipio limítrofe de Córdoba. Objetivo. Describir la ecología y la epidemiología de las infecciones por Rickettsia spp. en el Urabá antioqueño. Materiales y métodos. Se obtuvieron muestras de 354 roedores y se recolectaron 839 ectoparásitos de estos en los municipios de Apartadó, Turbo y Necoclí. Asimismo, se obtuvieron 220 sueros humanos. Estas muestras fueron estudiadas por reacción en cadena de la polimerasa (PCR) e inmunofluorescencia indirecta (IFI) para la detección de infección por rickettsias. Resultados. Por IFI se detectaron anticuerpos antirickettsias en 130 (43 %) de los roedores y en 53 (24 %) de los sueros humanos estudiados. Además, se amplificaron secuencias del gen gltA específicas del género Rickettsia en 23 (6,8 %) muestras de hígado de roedores, las cuales mostraron una similitud del 98,7 % con R. prowazekii . Una secuencia de gltA obtenida de larvas de garrapatas del género Amblyomma sp., tuvo una identidad mayor de 99 % con las secuencias de R. tamurae . Conclusión. Estos resultados demuestran la circulación de rickettsias en roedores, ectoparásitos y humanos en los municipios estudiados.

Introduction: Rickettsia spp. are tick, flea or lice-borne pathogenic bacterium, usually carried by rodents. In the last decade three outbreaks of rickettsial disease including fatalities, occurred in the provinces of Antioquia and Córdoba in northwestern Colombia. Objective: The purpose of this study was to perform an ecological and epidemiological description of the Rickettsia spp infection in the recently affected region of Colombia. Materials and methods: Samples were obtained from 354 rodents and their parasites captured in the municipalities of Apartadó, Turbo and Necoclí. Likewise, 220 human sera were also collected, for detection of infection by Rickettsia spp. Results: Indirect immunofluorescence assay (IFA) revealed that 130 (43%) of the rodents and 53 (24%) of the humans produced antibodies to Rickettsia spp. Additionally, rickettsial DNA was amplified by PCR from 23 (6.8%) rodent liver samples using primers directed to the genus specific gltA gene. While gltA sequences from rodent samples exhibited a 98.7% similitude with R . prowazekii, a sequence amplified from larvae of Amblyomma sp exhibited identities of >99% similarity with R. tamurae . Conclusion: These results demonstrate the presence of rickettsia in rodents, ectoparasites and humans throughout the municipalities studied.

Rickettsiosis transmitidas por garrapatas en las Américas: avances clínicos y epidemiológicos, y retos en el diagnóstico / Tick-borne rickettsioses in the Americas: clinical and epidemiological advances, and diagnostic challenges

Las rickettsiosis son entidades clínicas de tipo zoonótico, causadas por bacterias intracelulares estrictas de los géneros Rickettsia y Orientia, pertenecientes a la familia Rickettsiaceae. Su ecología está determinada por factores ambientales y la presencia de vectores específicos que condicionan el establecimiento y la epidemiología en diferentes regiones del mundo. En las Américas, durante el siglo XX, únicamente eran reconocidas tres de estas enfermedades: la fiebre manchada de las Montañas Rocosas, el tifus epidémico y el tifus endémico, Sin embargo, a partir del año 2000 se han descrito mas de 10 especies diferentes previamente desconocidas en este continente, tanto en artrópodos como en casos clínicos, hecho que permite clasificarlas como entidades clínicas emergentes y reemergentes. Dadas las manifestaciones clínicas de las enfermedades causadas por rickettsias, siendo la gran mayoría inespecíficas y, por lo mismo, compartidas con otras enfermedades infecciosas, especialmente virales y bacterianas, han sido enmarcadas entre los diagnósticos diferenciales del síndrome febril agudo, tanto en áreas urbanas como tropicales. En la actualidad, se cuenta con métodos diagnósticos directos e indirectos, que son útiles en la identificación del agente infeccioso, en este caso, causante de rickettsiosis.

Rickettsioses are a group of zoonotic diseases caused by strict intracellular bacteria of the genus Rickettsia and Orientia which belong to the Rickettsiaceae family. Their ecology is influenced by environmental factors and the presence of specific vectors that determine the establishment and epidemiology in different world regions. In America, during the 20 th century, only three of these diseases were recognized: Rocky Mountain spotted fever, epidemic typhus and endemic typhus. However, since 2000, more than 10 different species that had previously been unknown in this continent have been described, both in arthropods and in clinical cases, fact that classifies them as emerging and re-emerging diseases. Given the clinical manifestations of the diseases caused by rickettsias, being the majority unspecific and, therefore, shared with other infectious diseases, especially viral and bacterial, they have been framed within the differential diagnoses of acute febrile syndrome in urban and tropical areas. Nowadays, there are direct and indirect diagnostic methods, which are useful in the definition of the infectious agent, in this case, the cause of rickettsioses.

Seroprevalence of Ehrlichia canis, Ehrlichia chaffeensis and Ehrlichia ewingii in dogs in North America.

BACKGROUND: This study evaluated the exposure of dogs to three different Ehrlichia spp. in the south and central regions of the United States where vector-borne disease prevalence has been previously difficult to ascertain, particularly beyond the metropolitan areas. METHODS: Dog blood samples (n = 8,662) were submitted from 14 veterinary colleges, 6 private veterinary practices and 4 diagnostic laboratories across this region. Samples were tested for E. canis, E. chaffeensis and E. ewingii specific antibodies using peptide microtiter ELISAs. RESULTS: Overall, E. canis, E. chaffeensis and E. ewingii seroprevalence was 0.8%, 2.8%, and 5.1%, respectively. The highest E. canis seroprevalence (2.3%) was found in a region encompassing Arkansas, Louisiana, Oklahoma, Tennessee and Texas. E. chaffeensis seroreactivity was 6.6% in the central region (Arkansas, Kansas, Missouri, and Oklahoma) and 4.6% in the southeast region (Georgia, Maryland, North Carolina, South Carolina, Tennessee and Virginia). Seroreactivity to E. ewingii was also highest in the central region (14.6%) followed by the southeast region (5.9%). The geospatial pattern derived from E. chaffeensis and E. ewingii seropositive samples was similar to previous reports based on E. chaffeensis seroreactivity in white-tailed deer and the distribution of human monocytic ehrlichiosis (HME) cases reported by the CDC. CONCLUSIONS: The results of this study provide the first large scale regional documentation of exposure to E. canis, E. chaffeensis and E. ewingii in pet dogs, highlighting regional differences in seroprevalence and providing the basis for heightened awareness of these emerging vector-borne pathogens by veterinarians and public health agencies.

The ability of a topical novel combination of fipronil, amitraz and (S)-methoprene to protect dogs from Borrelia burgdorferi and Anaplasma phagocytophilum infections transmitted by Ixodes scapularis.

Healthy, purpose-bred laboratory beagle dogs that had not been exposed to ticks and were seronegative for Borrelia burgdorferi and Anaplasma phagocytophilum were randomly assigned to four groups of eight dogs each. Control group 1 was not treated. Groups 2, 3 and 4 were treated with a single topical application of a new formulation of fipronil, amitraz and (S)-methoprene (CERTIFECT™, Merial Limited, GA, USA) at 28, 21 or 14 days prior to tick infestation, respectively. Each dog was infested with 25 female and 25 male field-collected adult Ixodes scapularis ticks that had infection rates of 66% for B. burgdorferi sensu stricto and 23% for A. phagocytophilum, as determined by polymerase chain reaction. Two and five days after tick infestation, control dogs had an average of 9.5 and 13.9 attached adult female ticks, respectively, whilst the 24 treated dogs remained tick-free aside from a single tick on the 2nd day after infestation. Serial serological tests demonstrated that the ticks successfully infected 8/8 control dogs with B. burgdorferi and co-infected 6/8 with A. phagocytophilum. B. burgdorferi infection also was confirmed in most control dogs by culture (6/8) and PCR (7/8) of skin biopsies. In contrast, CERTIFECT protected all 24 treated dogs against infection by both B. burgdorferi and A. phagocytophilum, as demonstrated by their negative serological tests throughout the study and the absence of any positive skin biopsy culture or PCR in these dogs.

Tick saliva represses innate immunity and cutaneous inflammation in a murine model of Lyme disease.

Lyme borreliosis is an arthropod-borne disease transmitted by the Ixodes tick. This spirochetal infection is first characterized by a local cutaneous inflammation, the erythema migrans. The skin constitutes a key interface in the development of the disease. During Borrelia inoculation, tick saliva affects the innate and adaptive immunity of the vertebrate host skin. Some key mediators of innate immunity such as antimicrobial peptides (cathelicidin and defensin families) have been identified as important initiators of skin inflammation. We analyzed the role of tick saliva on integumental innate immunity using different protocols of Borrelia infection, via syringe or direct tick transmission. When syringe inoculation was used, Borrelia triggered skin inflammation with induction of CRAMP, the mouse cathelicidin, and tumor necrosis factor-alpha. However, when Borrelia was transmitted directly via the tick, we observed a significant repression of inflammatory genes, suggesting a critical role of tick saliva in skin innate immunity. For all the protocols tested, a peak of intense Borrelia multiplication occurred in the skin between days 5 and 15, before bacterial dissemination to target organs. We conclude that Borrelia pathogens specifically use the tick saliva to facilitate their transmission to the host and that the skin constitutes an essential interface in the development of Lyme disease.

Is sarcoidosis a rickettsiosis? An archival study.

BACKGROUND: Based on earlier research, Rickettsia helvetica could possibly be involved in the pathogenesis of sarcoidosis. Rickettsiae are transmitted to humans by a tick vector, Ixodes ricinus; this tick is highly prevalent in Northern Europe. We aimed to investigate the association between evidence of rickettsiae and sarcoidosis in histological samples. METHODS: We included formalin-fixed, paraffin-embedded mediastinal lymph node biopsies from 52 ethnic Danish patients with sarcoidosis and compared these with 50 biopsies from ethnic Danish patients with mediastinal lymphadenopathy of other causes. Samples were analysed for: (1) rickettsial DNA by real-time polymerase chain reaction (PCR) and (2) rickettsial rDNA (ribosomal DNA) by a specific fluorescence in situ hybridization technique (FISH). RESULTS: Rickettsia was not detected in biopsies by real-time PCR and/or FISH analyses. CONCLUSION: Our results do not support the hypothesis that Rickettsia is involved in the pathogenesis of sarcoidosis.

A febre maculosa no Brasil / Rocky Mountain spotted fever in Brazil

Embora no Brasil o número de casos confirmados de febre maculosa esteja em declínio desde 2005, a taxa de mortalidade (20 a 30 por cento) ainda é muito alta quando comparada a outros países. Esse alto índice de mortalidade tem estreita relação com a dificuldade em fazer o diagnóstico e estabelecer a terapia apropriada. Apenas dois grupos de antibióticos têm comprovada eficácia clínica, o cloranfenicol e as tetraciclinas. Até pouco tempo atrás, as tetraciclinas eram reservadas aos pacientes adultos em virtude das alterações dentárias e ósseas em crianças. Recentemente, entretanto, a Academia Americana de Pediatria e diversos autores têm recomendado a utilização da doxiciclina também em crianças. Em casos mais severos, a falta de experiência com uma tetraciclina injetável no Brasil faz com que se opte pelo cloranfenicol injetável. Como o pronto diagnóstico e a escolha adequada do fármaco são fatores determinantes de um prognóstico positivo, todos os profissionais da saúde devem estar melhor preparados para reconhecer e tratar a febre maculosa.

Although the number of confirmed cases of spotted fever has been declining in Brazil since 2005, the mortality rate (20 percent to 30 percent) is still high in comparison to other countries. This high mortality rate is closely related to the difficulty in making the diagnosis and starting the correct treatment. Only two groups of antibiotics have proven clinical effectiveness against spotted fever: chloramphenicol and tetracyclines. Until recently, the use of tetracyclines was restricted to adults because of the associated bone and tooth changes in children. Recently, however, the American Academy of Pediatrics and various researchers have recommended the use of doxycycline in children. In more severe cases, chloramphenicol injections are often preferred in Brazil because of the lack of experience with injectable tetracycline. Since early diagnosis and the adequate drug treatment are key to a good prognosis, health care professionals must be better prepared to recognize and treat spotted fever.

[Two cases of Crimean-Congo haemorrhagic fever (CCHF) in two tourists in Senegal in 2004]. / Deux cas de fièvre hémorragique de Crimée-Congo (FHCC) contractée au Sénégal, en 2004, par des résidentes temporaires.

Two cases of Crimean-Congo haemorrhagic fever (CCHF) occurred in two French tourists during their visit in Senegal in November 2004. Febrile and hemorrhagic syndrome with ulorrhagia, petechiae, haematemesis, haematomas associated with biological signs of disseminated intramuscular coagulation were observed. For the first case who had a medical evacuation to France before diagnosis, Crimean-Congo virus infection was revealed by laboratory tests performed by the National Reference Center for Hemorrhagic Fevers (NRCHF, Institut Pasteur, Lyon) and secondly by the Centre de Référence OMS sur la Recherche des Arbovirus et des virus des Fièvres Hémorragiques (CRORA) in the Dakar Pasteur Institute (DPI). The second case diagnosed by the CRORA died after clinical deterioration with liver failure and severe haemorrhages. Healthcare workers and family members who had contact with tissue or blood from patients were followed up after the putative exposure either in France or in Senegal.