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Vaccines Jan 2023In recent years, promising vaccination strategies against rickettsiosis have been described in experimental animal models and human cells. OmpB is considered an...
In recent years, promising vaccination strategies against rickettsiosis have been described in experimental animal models and human cells. OmpB is considered an immunodominant antigen that is recognized by T and B cells. The aim of this study was to identify TCD4+INF-γ+ and TCD8+INF-γ+ lymphocytes in an autologous system with macrophages transfected with the vaccine candidate pVAX1-OmpB24. Lymphocytes and monocytes from 14 patients with Rickettsia were isolated from whole blood. Monocytes were differentiated into macrophages and transfected with the plasmid pVAX1-OmpB24 pVax1. Isolated lymphocytes were cultured with transfected macrophages. IFN-γ-producing TCD4+ and TCD8+ lymphocyte subpopulations were identified by flow cytometry, as was the percentage of macrophages expressing CD40+, CD80+, HLA-I and HLA-II. Also, we analyzed the exhausted condition of the T lymphocyte subpopulation by PD1 expression. Macrophages transfected with pVAX1-OmpB24 stimulated TCD4+INF-γ+ cells in healthy subjects and patients infected with . Macrophages stimulated TCD8+INF-γ+ cells in healthy subjects and patients infected with and . Cells from healthy donors stimulated with OmpB-24 showed a higher percentage of TCD4+PD1+. Cells from patients infected with had a higher percentage of TCD8+PD-1+, and for those infected with the larger number of cells corresponded to TCD4+PD1+. Human macrophages transfected with pVAX1-OmpB24 activated TCD4+IFN-γ+ and CD8+IFN-γ+ in patients infected with different Rickettsia species. However, PD1 expression played an important role in the inhibition of T lymphocytes with
PubMed: 36680017
DOI: 10.3390/vaccines11010173 -
Travel Medicine and Infectious Disease 2023We report an isolated outbreak of Rickettsia rickettsii in the Ngäbe-Buglé indigenous region, located 750 m (tropical wet) above sea level, in a jungle and...
We report an isolated outbreak of Rickettsia rickettsii in the Ngäbe-Buglé indigenous region, located 750 m (tropical wet) above sea level, in a jungle and mountainous area of Western Panama. Seven members of a family were infected simultaneously, resulting in four deaths. Family outbreaks have been previously described and are responsible for 4-8% of the cases described [1-4]. The simultaneous onset of symptoms in the affected population group is extremely unusual [1,5], but it should not dissuade the clinician from considering the possibility of Rickettsia rickettsii infection.
Topics: Humans; Rickettsia rickettsii; Rocky Mountain Spotted Fever; Disease Outbreaks; Panama; Rickettsia
PubMed: 36646398
DOI: 10.1016/j.tmaid.2023.102542 -
Ticks and Tick-borne Diseases Mar 2023Rickettsioses are vector-borne zoonotic diseases whose etiological agents are bacteria of the genera Rickettsia and Orientia. In Colombia, literature published on...
Rickettsioses are vector-borne zoonotic diseases whose etiological agents are bacteria of the genera Rickettsia and Orientia. In Colombia, literature published on rickettsioses during the 20th century is limited and disperse; to date, there are no detailed publications that compile the affected regions or the involved Rickettsia species in each outbreak. Since early works of Luis Patiño-Camargo, the study of rickettsioses gained major importance with the subsequent description of significant outbreaks in some departments of the country. During the 1940s, many articles were published reporting outbreaks probably caused by Rickettsia rickettsii, Rickettsia typhi, and Rickettsia prowazekii, as well as studies on their diagnosis, vaccination, and prophylaxis. One of the most notorious works was published by Patiño-Camargo where he named the R. rickettsii rickettsiosis as "Tobia fever". However, in the subsequent decades, these entities entered a prolonged period of neglected research and surveillance, and just gained importance until the 21st century, when new fatal cases began to be reported in the country; thus, many questions remained unanswered during this overlooked period. The present work reviewed online databases, repositories, and libraries to compile literature related to rickettsioses in Colombia published during the 20th century. Gathered data show that typhus group rickettsioses (including infections by R. typhi and R. prowazekii) were broadly distributed in departments from the Andean and Caribbean regions, and that spotted fever group rickettsioses cases (including infections by R. rickettsii) were registered in other locations different from Tobia (Cundinamarca), like Atlántico, Bolivar, and Santander departments. These findings contribute to the knowledge of these diseases, their historical distribution, public health burden, and set new horizons for rickettsioses research in different Colombian locations.
Topics: Male; Humans; Colombia; Rickettsia Infections; Rickettsia; Rickettsia prowazekii; Rickettsia rickettsii
PubMed: 36628901
DOI: 10.1016/j.ttbdis.2022.102118 -
Journal of the American Veterinary... Dec 2022To assess exposure to and infection with 3 pathogens (Rickettsia rickettsii, Anaplasma platys, and Ehrlichia canis) vectored by brown dog ticks (Rhipicephalus...
OBJECTIVE
To assess exposure to and infection with 3 pathogens (Rickettsia rickettsii, Anaplasma platys, and Ehrlichia canis) vectored by brown dog ticks (Rhipicephalus sanguineus) in sheltered dogs at the western US-Mexico border.
ANIMALS
239 dogs in shelters in San Diego and Imperial counties, US, and Mexicali and Tijuana, Mexico.
PROCEDURES
Each dog had blood drawn and basic demographic data collected. PCR was performed to determine active infection with Rickettsia spp, E canis, and A platys. Serology was performed to determine exposure to Rickettsia, Anaplasma, and Ehrlichia species.
RESULTS
2 of 78 (2.6%) dogs sampled in Tijuana were actively infected with R rickettsii. A single brown dog tick collected from a dog in Tijuana was PCR-positive for R rickettsii. Infection with E canis and A platys ranged across shelters from 0% to 27% and 0% to 33%, respectively. Dogs in all 4 locations demonstrated exposure to all 3 pathogens, though Rickettsia and Ehrlichia seropositivity was highest in Mexicali (81% and 49%, respectively) and Anaplasma seropositivity was highest in Tijuana (45%).
CLINICAL RELEVANCE
While infection and exposure were highest in sheltered dogs in the southern locations, dogs in all locations demonstrated exposure to all pathogens, demonstrating the potential for emergence and spread of zoonotic pathogens with significant public health consequences in southern California and northern Baja California. In addition, veterinarians and shelter staff should be aware that Ehrlichia or Anaplasma infection may co-occur with Rocky Mountain spotted fever, which is a human health risk.
Topics: Dogs; Humans; Animals; Rocky Mountain Spotted Fever; Mexico; One Health; Rhipicephalus sanguineus; Anaplasma; Anaplasmosis; Dog Diseases
PubMed: 36563069
DOI: 10.2460/javma.22.08.0388 -
Tropical Medicine and Infectious Disease Dec 2022Ticks can carry and transmit a large number of pathogens, including bacteria, viruses and protozoa, posing a huge threat to human health and animal husbandry. Previous...
Ticks can carry and transmit a large number of pathogens, including bacteria, viruses and protozoa, posing a huge threat to human health and animal husbandry. Previous investigations have shown that the dominant species of ticks in Shanghai are and . However, no relevant investigations and research have been carried out in recent decades. Therefore, we investigated the bacterial communities and tick-borne pathogens (TBPs) in spp. from Shanghai, China. Ixodid ticks were collected from 18 sites in Shanghai, China, and identified using morphological and molecular methods. The V3-V4 hypervariable regions of the bacterial 16S rRNA gene were amplified from the pooled tick DNA samples and subject to metagenomic analysis. The microbial diversity in the tick samples was estimated using the alpha diversity that includes the observed species index and Shannon index. The Unifrac distance matrix as determined using the QIIME software was used for unweighted Unifrac Principal coordinates analysis (PCoA). Individual tick DNA samples were screened with genus-specific or group-specific nested polymerase chain reaction (PCR) for these TBPs and combined with a sequencing assay to confirm the results of the V3-V4 hypervariable regions of the bacterial 16S rRNA gene. We found and to be the dominant species of ticks in Shanghai in this study. Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria are the main bacterial communities of spp. The total species abundances of Proteobacteria, Firmicutes and Bacteroidetes, are 48.8%, 20.8% and 18.1%, respectively. At the level of genus analysis, and carried at least 946 genera of bacteria. The bacteria with high abundance include , , and . Additionally, , , , , , , spp. and -like endosymbiont were detected in spp. from Shanghai, China. This study is the first report of bacterial communities and the prevalence of some main pathogens in spp. from Shanghai, China, and may provide insights and evidence for bacterial communities and the prevalence of the main pathogen in ticks. This study also indicates that people and other animals in Shanghai, China, are exposed to several TBPs.
PubMed: 36548668
DOI: 10.3390/tropicalmed7120413 -
Journal of Equine Veterinary Science Jan 2023Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity...
Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity and mortality and, in some cases, to their zoonotic relevance. Understanding the host immune/inflammatory response to the pathogens is crucial to develop effective methods of diagnosis, control and treatment. This study aimed to evaluate red blood cells (RBC), hematocrit (Hct), hemoglobin concentration (Hb), mean cell volume (MCV), mean cell hemoglobin content (MCH), mean cell hemoglobin (MCHC), platelets (PLT), white blood cells (WBC), leukocytes populations, and serum protein pattern of Sardinian donkeys scored positive to tick-borne pathogens. Thirty donkeys were dived in five groups, six subjects each: Group 1, tested negative to pathogens (control group); Group 2, donkeys infected by Theileria equi; Group 3, donkeys infected by Ehrlichia equi; Group 4, donkeys infected by Rickettsia Rickettsii; Group 5, donkeys co-infected by T. equi, E. equi and R. Rickettsii. From donkeys blood samples were collected and haematological and serum protein profiles were assessed. One-way ANOVA showed lower red blood cells, haemoglobin, platelets, lymphocytes and neutrophils values, and higher eosinophils, basophils, serum total proteins, α2-, β- and γ- globulins values in donkeys infected by one or more pathogens compared to control group (P < .05). The study highlighted an immune and inflammatory response of donkeys positive to E. equi, T. equi, and R. Rickettsii and represents a starting point for further investigations in the field to fill the gaps currently existing on the complex interwoven relationship between the pathogen and host immune and inflammatory response in equids.
Topics: Horses; Animals; Equidae; Ticks; Theileria; Rickettsia rickettsii
PubMed: 36509242
DOI: 10.1016/j.jevs.2022.104190 -
Pathogens (Basel, Switzerland) Nov 2022In 2021, 273 Rocky Mountain spotted fever cases were reported nationwide in Mexico. In Chihuahua City, fourteen samples were obtained from children suspected of...
In 2021, 273 Rocky Mountain spotted fever cases were reported nationwide in Mexico. In Chihuahua City, fourteen samples were obtained from children suspected of rickettsial infection. The analysis of samples (January to December 2021) showed prevalence rates of 28.5%, 43%, and 28.5% for Rickettsia rickettsii, Ehrlichia canis, and both pathogens in coinfection, respectively. The analysis of clinical haematological and biochemistry analytes showed alterations; 100% of the children had elevated liver enzymes and coagulation times, 64% showed leukocytosis due to neutrophilia, 55% had thrombocytopenia, lymphopenia, and hypoalbuminemia, and 45% showed normocytic normochromic anaemia. Statistically significant differences were observed in the expression of the chemokines IL-8, RANTES, CXCL9/MIG, and CXCL10/IP-10 across the coinfected and control groups, and the difference in IP-10 expression was significant for patients infected by R. rickettsii compared to the control group. Additionally, significant differences were observed for expression levels of IL-1β, IL-6, IL-17, IFNγ, and TNFα among the R. rickettsii-positive group compared to the control group. On the other hand, the coinfected group exhibited modified levels of IL-6, IL-8, and IL-10 compared with the control group. Finally, significant differences were observed for CD8+ T lymphocyte subpopulations between individuals positive for R. rickettsii and those positive for E. canis.
PubMed: 36422602
DOI: 10.3390/pathogens11111351 -
Revista Do Instituto de Medicina... 2022Brazilian spotted fever, a zoonotic disease transmitted by ticks, is caused by Rickettsia rickettsii. We report a fulminant case of this zoonosis in a healthy...
Brazilian spotted fever, a zoonotic disease transmitted by ticks, is caused by Rickettsia rickettsii. We report a fulminant case of this zoonosis in a healthy 46-year-old military man in the urban region of Rio de Janeiro city, in October, 2021. Ticks and capybaras (Amblyomma sculptum, Hydrochoerus hydrochaeris, respectively) were identified in the military fields, pointing to the participation of this large synanthropic rodent, recognized as an efficient amplifier host of Rickettsia rickettsii in Brazil. As the military population is considered a risk group for spotted fever, it is necessary to alert health professionals to the importance of the early detection of the disease and its adequate management, mainly in populations that are particularly at risk of exposure to ticks, in order to avoid fatal outcomes.
Topics: Animals; Humans; Rocky Mountain Spotted Fever; Military Personnel; Brazil; Rickettsia rickettsii; Rodentia; Ticks
PubMed: 36383899
DOI: 10.1590/S1678-9946202264077 -
Experimental & Applied Acarology Dec 2022From June 2013 to January 2014, blood sera samples and ticks were collected from domestic dogs and wild small mammals, and ticks from the vegetation in a preservation...
From June 2013 to January 2014, blood sera samples and ticks were collected from domestic dogs and wild small mammals, and ticks from the vegetation in a preservation area of the Atlantic Forest biome (Turvo State Park), and the rural area surrounding the Park in Derrubadas municipality, state of Rio Grande do Sul, southern Brazil. Dogs were infested by Amblyomma ovale and Amblyomma aureolatum adult ticks, whereas small mammals were infested by immature stages of A. ovale, Amblyomma yucumense, Amblyomma brasiliense, Ixodes loricatus, and adults of I. loricatus. Ticks collected on vegetation were A. brasiliense, A. ovale, A. yucumense, Amblyomma incisum, and Haemaphysalis juxtakochi. Three Rickettsia species were molecularly detected in ticks: Rickettsia bellii in I. loricatus (also isolated through cell culture inoculation), Rickettsia amblyommatis in A. brasiliense, and Rickettsia rhipicephali in A. yucumense. The latter two are tick-rickettsia associations reported for the first time. Seroreactivity to Rickettsia antigens were detected in 33.5% (55/164) small mammals and 8.3% (3/36) canine sera. The present study reveals a richness of ticks and associated-rickettsiae in the largest Atlantic Forest Reserve of the state of Rio Grande do Sul, which is characterized by a rich fauna of wild mammals, typical of more preserved areas of this biome. Noteworthy, none of the detected Rickettsia species have been associated to human or animal diseases. This result contrasts to other areas of this biome in Brazil, which are endemic for tick-borne spotted fever caused by Rickettsia rickettsii or Rickettsia parkeri.
Topics: Humans; Dogs; Animals; Ticks; Brazil; Mammals
PubMed: 36344862
DOI: 10.1007/s10493-022-00754-3 -
The Veterinary Clinics of North... Nov 2022Spotted fever rickettsioses are important causes of emerging infectious disease in the United States and elsewhere. Rocky Mountain Spotted Fever, caused by R. rickettsii... (Review)
Review
Spotted fever rickettsioses are important causes of emerging infectious disease in the United States and elsewhere. Rocky Mountain Spotted Fever, caused by R. rickettsii causes a febrile, acute illness in dogs. Because it circulates in peripheral blood in low copy number and because of the acute nature of the disease, dogs may test PCR and seronegative at the time of presentation. Therefore, therapy with doxycycline must be initiated and continued based on the clinician's index of suspicion. Combining PCR with serologic testing, repeat testing of the same pre-antimicrobial blood sample, and testing convalescent samples for seroconversion facilitates diagnosis. The prognosis can be excellent if appropriate antimicrobial therapy is begun in a timely fashion. It is well established that dogs are sentinels for infection in people in households and communities. Whether R. rickettsii causes illness in cats is not well established. The role of other spotted fever group rickettsia in causing illness in dogs and cats is being elucidated. Veterinarians should keep in mind that novel and well characterized species of SFG Rickettsia are important causes of emerging infectious disease. Veterinarians can play an important role in detecting, defining, and preventing illness in their canine patients and their human companions.
Topics: Humans; Dogs; Animals; United States; Cats; Communicable Diseases, Emerging; Cat Diseases; Dog Diseases; Rickettsia Infections; Rocky Mountain Spotted Fever; Spotted Fever Group Rickettsiosis; Rickettsia; Anti-Bacterial Agents
PubMed: 36336422
DOI: 10.1016/j.cvsm.2022.07.003