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BioRxiv : the Preprint Server For... Jul 2023Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the Transitional Group (TRG), Typhus Group (TG), and Spotted...
UNLABELLED
Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the Transitional Group (TRG), Typhus Group (TG), and Spotted Fever Group (SFG) rickettsiae infect blood-feeding arthropods, have dissimilar clinical manifestations, and possess unique genomic and morphological attributes. Lacking glycolysis, rickettsiae pilfer numerous metabolites from host cytosol to synthesize peptidoglycan and lipopolysaccharide (LPS). For LPS, O-antigen immunogenicity varies between SFG and TG pathogens; however, lipid A proinflammatory potential is unknown. We previously demonstrated that (TRG), (TG), and (SFG) produce lipid A with long 2' secondary acyl chains (C16 or C18) compared to short 2' secondary acyl chains (C12) in (SFG) lipid A. To further probe this structural heterogeneity and estimate a time point when shorter 2' secondary acyl chains originated, we generated lipid A structures for two additional SFG rickettsiae ( and ) utilizing Fast Lipid Analysis Technique adopted for use with tandem mass spectrometry (FLAT ). FLAT allowed analysis of lipid A structure directly from host cell-purified bacteria, providing substantial improvement over lipid A chemical extraction. FLAT -derived structures indicate SFG rickettsiae diverging after evolved shorter 2' secondary acyl chains. Bioinformatics analysis of LpxL late acyltransferases revealed discrete active sites and hydrocarbon rulers for long versus short 2' secondary acyl chain addition. While the significance of different lipid A structures for diverse pathogens is unknown, our success using FLAT will facilitate determining how structural heterogeneity impacts interactions with host lipid A receptors and overall inflammatory potential.
IMPORTANCE
Deforestation, urbanization, and homelessness lead to spikes in Rickettsioses. Vector-borne human pathogens of Transitional Group (TRG), Typhus Group (TG), and Spotted Fever Group (SFG) rickettsiae differ by clinical manifestations, immunopathology, genome composition, and morphology. We previously showed that lipid A (or endotoxin), the membrane anchor of Gram-negative bacterial lipopolysaccharide (LPS), structurally differs in (later-evolving SFG) relative to (basal SFG), (TG), and (TRG). As lipid A structure influences recognition potential in vertebrate LPS sensors, further assessment of lipid A structural heterogeneity is needed. Here, we sidestepped the difficulty of lipid A chemical extraction by utilizing FLAT , a new procedure for generating lipid A structures directly from host cell-purified bacteria. These data confirm later-evolving SFG pathogens synthesize structurally distinct lipid A. Our findings impact interpreting immune responses to different pathogens and utilizing lipid A adjuvant or anti-inflammatory properties in vaccinology.
PubMed: 37461656
DOI: 10.1101/2023.07.06.547954 -
Travel Medicine and Infectious Disease 2023
Topics: Animals; Humans; Rickettsia rickettsii; Rickettsia; Ticks; Panama
PubMed: 37271199
DOI: 10.1016/j.tmaid.2023.102595 -
Travel Medicine and Infectious Disease 2023
Topics: Animals; Humans; Rickettsia rickettsii; Rickettsia; Ticks; Panama
PubMed: 37268084
DOI: 10.1016/j.tmaid.2023.102596 -
Journal of Parasitic Diseases :... Jun 2023In the present study, epidemiological analysis on 839 ticks collected from 50 cattle in Gadag district, Karnataka state, tick identification and detection of tick-borne...
In the present study, epidemiological analysis on 839 ticks collected from 50 cattle in Gadag district, Karnataka state, tick identification and detection of tick-borne pathogens was conducted by PCR, sequencing, and phylogeny. The morphological identification revealed that spp. [48.6%], spp. [48.4%], and spp. [3.0%] tick genera in Gadag district. Further, a higher infestation of spp. [69.0%] and spp. [62.3%] in Shirahatti and Gadag taluk, respectively was observed. Based on the taluk-wise and tick genus-wise analysis, a higher number of ticks was present in the dewlap region of cattle body sites, except for spp., the majority of which was present in the neck. Tick genus prevalence was 45.1, 42.7%, and 12.2 for spp., spp., and spp., respectively. The mean tick per cattle was 11.6, 11.0, and 2.5 for spp., spp., and spp., respectively. The prevalence of , spp., and was 8.0, 6.4, and 6.4%, respectively in the tick DNA samples and was negative for and spp. The sequencing of the cytochrome oxidase subunit 1 gene revealed the presence of , , and tick species in the Gadag district. The phylogenetic analysis revealed the tick species have similarities and identity with the isolates from India and neighboring countries. Thus, the study provides knowledge on tick genus distribution and tick-borne pathogens in Gadag district, Karnataka which will help in developing the control and prevention strategies by the policymakers and for profitable dairy farming by farmers.
PubMed: 37193487
DOI: 10.1007/s12639-023-01584-9 -
Animals : An Open Access Journal From... Apr 2023Brazilian spotted fever (BSF) is the most important tick-borne diseases affecting humans in Brazil. Cases of BSF have recently been reported in the Goiás state,...
Brazilian spotted fever (BSF) is the most important tick-borne diseases affecting humans in Brazil. Cases of BSF have recently been reported in the Goiás state, midwestern Brazil. All cases have been confirmed by reference laboratories by seroconversion to antigens. Because serological cross-reactions among different rickettsial species that belong to the spotted fever group (SFG) are common, the agent responsible for BSF cases in Goiás remains unknown. From March 2020 to April 2022, ticks and plasma were collected from dogs, horses and capybaras (), and from the vegetation in an area where BSF cases have been reported and two areas under epidemiological surveillance in Goiás. Horses were infested by , and ; dogs by sensu lato (s.l.), and , and capybaras by and . Adults of , , and immature stages of and , and spp. were collected from the vegetation. DNA of that did not belong to the SFG was detected in , which was identified by DNA sequencing as . Seroreactivity to SFG and antigens was detected in 25.4% (42/165) of dogs, 22.7% (10/44) of horses and 41.2% (7/17) of capybaras, with higher titers for in dogs and capybaras. The seropositivity of animals to SFG spp. antigens demonstrates the circulation of SFG rickettsiae in the region. Further research is needed to fully determine the agent responsible for rickettsiosis cases in this area.
PubMed: 37106851
DOI: 10.3390/ani13081288 -
Ticks and Tick-borne Diseases Jul 2023Ticks are vectors for several pathogens, including bacteria belonging to the Rickettsia genus, such as Rickettsia rickettsii and Rickettsia parkeri, the causative agents...
Ticks are vectors for several pathogens, including bacteria belonging to the Rickettsia genus, such as Rickettsia rickettsii and Rickettsia parkeri, the causative agents of spotted fever. The aim of the present study was to investigate the tick species richness and rickettsial agents associated with wild birds captured in the Humaita Forest Reserve, Acre, in the Western Amazon region. Wild birds were captured with ornithological nets for visual inspection with the purpose of collecting ticks, which were identified through morphological analyses and molecular tests for several genes (12S rDNA, 16S rDNA, gltA, ompA, and sca4). A total of 607 wild birds were captured, 12% of which were parasitized by 268 ticks of the Amblyomma genus, with new host-parasite associations reported for Amblyomma calcaratum, Amblyomma geayi, Amblyomma longirostre, Amblyomma naponense, Amblyomma nodosum, and Amblyomma varium. Of the total ticks collected, 113 were tested for the presence of rickettsial DNA fragments, with 19 testing positive for R. parkeri in A. geayi, Rickettsia tamurae-like in Amblyomma sp., and Rickettsia amblyommatis in A. geayi, A. longirostre, and Amblyomma sp. We detected R. tamurae-like in Amblyomma larvae for the first time in the Western Brazilian Amazon biome, and registered spotted fever group rickettsiae, although the relevance of the detected species in a public health context should be further explored in South America, as well as new host-parasite interactions in this underexplored region.
Topics: Animals; Ticks; Ixodidae; Brazil; Tick Infestations; Rickettsia; Animals, Wild; Spotted Fever Group Rickettsiosis; Amblyomma; Birds; DNA, Ribosomal
PubMed: 37100028
DOI: 10.1016/j.ttbdis.2023.102182 -
Acta Tropica Jun 2023Neglected bacterial zoonoses are a group of Neglected Tropical Diseases (NTDs) that are commonly underdiagnosed and underreported due to their undifferentiated febrile...
Neglected bacterial zoonoses are a group of Neglected Tropical Diseases (NTDs) that are commonly underdiagnosed and underreported due to their undifferentiated febrile illness symptomology. Spotted fever group rickettsioses (SFGR), a subset of tick-borne bacterial zoonoses, belong in this group. There is a dichotomy in the reporting and recognition of these pathogens in Central America: countries with reduced human development scores-like El Salvador-have little to no research or surveillance dedicated to these pathogens and the diseases they cause. This was the third-ever tick survey in El Salvador, highlighting the knowledge gap in this country. A total of 253 ticks were collected from 11 animals at two farm sites and one veterinary office. Standard and quantitative PCR were used to detect presence of SFGR, Ehrlichia, and Anaplasma sp. pathogens in ticks. Ehrlichia sp. were detected in 2.4% of all collected ticks and Anaplasma sp. were detected in 5.5% of all ticks. Rickettsia rickettsii was amplified in 18.2% of ticks, and amplicons similar to R. parkeri, and R. felis were found in 0.8% and 0.4%, of collected ticks, respectively. This is the first report of these pathogenic bacterial species in El Salvador. This study emphasizes the need for further surveillance and research including incorporating additional human seroprevalence and testing to understand the public health burden in this country.
Topics: Animals; Humans; Rickettsia; Ehrlichia; Ticks; Anaplasma; Bacterial Zoonoses; El Salvador; Seroepidemiologic Studies; Tick-Borne Diseases
PubMed: 37030489
DOI: 10.1016/j.actatropica.2023.106909 -
Journal of Medical Entomology May 2023Ticks and tick-borne diseases are increasing in the United States, including New Hampshire (NH). We report on the findings of an ongoing free crowdsourcing program...
Ticks and tick-borne diseases are increasing in the United States, including New Hampshire (NH). We report on the findings of an ongoing free crowdsourcing program spanning four years within NH. The date of tick's submission was recorded along with species, sex, stage, location they were collected (translated into latitude and longitude), the activity the individual was doing when the tick was found, and host species. A total of 14,252 ticks belonging to subclass Acari, family Ixodidae and genera Ixodes, Dermacentor, Amblyomma, and Haemaphysalis was recorded from the period 2018-2021 throughout NH. A total of 2,787 Ixodes scapularis and 1,041 Dermacentor variabilis, were tested for the presence of Borrelia sp. (Spirochaetales: Spirochaetaceae), B. burgdorferi sensu lato, B. miyamotoi, B. mayonii, Babesia microti (Piroplasmida: Babesiidae), Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), Francisella tularensis (Thiotrichales: Francisellaceae), and Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) by PCR. For the I. scapularis ticks tested, the pathogen prevalence was 37% B. burgdorferi s.l. 1% B. miyamotoi, 6% A. phagocytophilum, and 5% Ba. microti. Only one D. variabilis resulted positive to F. tularensis. We created state-wide maps informing the differences of ticks as detailed by administrative divisions. Dermacentor variabilis peaked in June and I. scapularis peaked in May and October. The most reported activity by people with tick encounters was while walking/hiking, and the least was biking. Using the reported distribution of both species of ticks, we modeled their climate suitability in the target territory. In NH, I. scapularis and D. variabilis have distinct patterns of emergence, abundance, and distribution. Tick prevention is important especially during April-August when both tick species are abundant and active.
Topics: Animals; New Hampshire; Ixodes; Ixodidae; Borrelia; Borrelia burgdorferi
PubMed: 37030013
DOI: 10.1093/jme/tjad030 -
Ticks and Tick-borne Diseases Jul 2023Amblyomma is an important tick genus for animal and human health, with some species being the vectors of zoonotic pathogens, such as Rickettsia rickettsii, in the...
Amblyomma is an important tick genus for animal and human health, with some species being the vectors of zoonotic pathogens, such as Rickettsia rickettsii, in the Neotropical region. Knowing their hosts may help to understand the distribution of these agents and decrease the occurrence of clinical cases. Primates are intelligent and adaptable animals that can get close to humans in the search for food. So, they may be an important epidemiological link for the spread of these ticks. Beyond that, primates also suffer from these infections, serving as sentinels for different diseases. Thus, the present study aims to report the parasitism by Amblyomma spp. on six species of Neotropical primates from different locations in Brazil. The 337 collected ticks were morphologically identified using stereomicroscopes and taxonomic keys, and six distinct species of ticks were identified. We report here the first record of nymphs of the tick species Amblyomma cajennense sensu stricto on Alouatta belzebul, a male of Amblyomma fuscum on Alouatta guariba clamitans, nymphs of Amblyomma sculptum on Leontopithecus chrysopygus and Callithrix aurita, as well as nymphs of Amblyomma geayi on Saimiri collinsi. Of the 337 tick specimens collected, 256 (75,96%) were nymphs. The importance of primates in the life cycle of these species remains to be elucidated.
Topics: Animals; Male; Humans; Ticks; Amblyomma; Ixodidae; Brazil; Primates; Rickettsia
PubMed: 36966542
DOI: 10.1016/j.ttbdis.2023.102169