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Vector Borne and Zoonotic Diseases... Dec 2021In the United States, and are considered key vectors for , the causative agent of Rocky Mountain spotted fever. Through regional surveillance, a wide diversity of...
In the United States, and are considered key vectors for , the causative agent of Rocky Mountain spotted fever. Through regional surveillance, a wide diversity of spp. have been documented in , and spp. has been suggested as potential vectors for various other pathogens, including spp. and . To better define the prevalence and diversity of pathogens in spp. across the United States, 848 ticks collected from dogs and cats in 44/50 states in 2018-2019 were tested by PCR for spp.-specific 17 kDa and ompA gene fragments; a subset of spp. was also tested with PCR, targeting fragments of the 18S and large subunit region rRNA genes of spp. and 16S rRNA genes of . spp. was identified in 12.5% (106/848) of ticks. Species detected include ( = 64 ticks), ( = 15 ticks), ( = 13 ticks), ( = 8 ticks), ( = 3 ticks), ( = 1 tick), and unclassified spp. ( = 2 ticks). Ticks with and were submitted from every U.S. region; was predominantly detected in ticks from the southern half of the United States, and all -positive ticks were that originated from the Rocky Mountain states. was not detected in any spp., and was detected in two . Because most ticks had fed on dogs or cats before submission, these findings do not implicate a given sp. as a primary vector of these agents, but in regard to spp., the data do support other published work showing harbors a diversity of species with unknown implications for animal and human health.
Topics: Animals; Babesia; Cat Diseases; Cats; Dermacentor; Dog Diseases; Dogs; RNA, Ribosomal, 16S; Rickettsia; United States
PubMed: 34958266
DOI: 10.1089/vbz.2021.0047 -
Current Research in Parasitology &... 2022Ticks are blood-sucking arthropods that parasitize most groups of terrestrial or semiaquatic vertebrates. Humans are accidental hosts to the ticks; however, in humans... (Review)
Review
Ticks are blood-sucking arthropods that parasitize most groups of terrestrial or semiaquatic vertebrates. Humans are accidental hosts to the ticks; however, in humans the ticks can cause damages varying from simple irritation to severe allergies, toxicosis, paralysis, and the transmission of pathogens, some of which can be fatal. Central America represents a narrow isthmus between North and South America and is considered a biodiversity hotspot. The importance of tick-borne diseases in this region is manifested by fatal outbreaks caused by , severe and mild cases of other rickettsioses, ehrlichiosis, and tick-borne relapsing fevers, in addition to cases paralysis and strong allergic reactions. Even so, this information is scarce in most countries of this region, and there are no epidemiological data. In this article we present a review of the ticks that parasitize humans in Central America, covering data from the 19th Century to the present day. Of nearly 80 tick species reported in Central America, 28 species are reported on humans. This list includes species that thrive within homes, grazing areas and, to a lesser extent, in wild environments, both in lowland and high mountain forests. The most important genus in this region is , followed by and , and to a lesser extent , and . These data provide information on the tick species most commonly associated with humans in Central America, and highlight the potential for tick-borne diseases in wild, rural and urban regions.
PubMed: 36589874
DOI: 10.1016/j.crpvbd.2021.100065 -
Pathogens (Basel, Switzerland) Nov 2021American bison () is listed as near-threatened and in danger of extinction in Mexico. Recent studies have demonstrated the presence of several emerging pathogens at the...
American bison () is listed as near-threatened and in danger of extinction in Mexico. Recent studies have demonstrated the presence of several emerging pathogens at the Janos Biosphere Reserve (JBR), inhabited by one wild herd of American bison. Blood samples were collected from 26 American bison in the JBR. We tested for the presence of , , , , and DNA using nested and semi-nested PCR protocols performing duplicates in two different laboratories. Results showed three animals (11.5%) positive for , three more (11.5%) for and four (19.2%) for . Two individuals were co-infected with and . We found no animals positive for and . This is the first report in America of in American bison. American bison has been described as an important reservoir for pathogens of zoonotic and veterinary importance; thus, the presence of tick-borne pathogen DNA in the JBR American bison indicates the importance of continuous wildlife health surveys.
PubMed: 34832584
DOI: 10.3390/pathogens10111428 -
The Korean Journal of Parasitology Oct 2021Ticks can transmit pathogenic bacteria, protozoa, and viruses to humans and animals. In this study, we investigated the microbiomes of Haemaphysalis longicornis...
Ticks can transmit pathogenic bacteria, protozoa, and viruses to humans and animals. In this study, we investigated the microbiomes of Haemaphysalis longicornis according to sex and life stages. The Shannon index was significantly higher for nymphs than adult ticks. Principal coordinates analysis showed that the microbiome composition of female adult and male adult ticks were different. Notably, Coxiella-like bacterium (AB001519), known as a tick symbiont, was found in all nymphs and female adult ticks, but only one out of 4 male adult ticks had Coxiella-like bacterium (AB001519). In addition, Rickettsia rickettsii, Coxiella burnetii, and Anaplasma bovis were detected in this study.
Topics: Anaplasma; Animals; Female; Humans; Ixodidae; Male; Microbiota; Republic of Korea; Rickettsia; Ticks
PubMed: 34724768
DOI: 10.3347/kjp.2021.59.5.489 -
Biomedica : Revista Del Instituto... Oct 2021Introduction: Rickettsioses are zoonotic diseases transmitted by arthropods acting as vectors and reservoirs. Disease symptoms are nonspecific and, therefore, their...
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.
Topics: Adult; Antibodies, Bacterial; Colombia; Humans; Rickettsia; Rickettsia Infections; Seroconversion; Seroepidemiologic Studies
PubMed: 34669282
DOI: 10.7705/biomedica.5712 -
Pathogens (Basel, Switzerland) Sep 2021Regional differences in tick-borne disease epidemiology may be related to biological variations between vector populations. (Ixodida: Ixodidae), a neotropical tick, is...
Regional differences in tick-borne disease epidemiology may be related to biological variations between vector populations. (Ixodida: Ixodidae), a neotropical tick, is known from several regions in Brazil. However, only in the metropolitan area of São Paulo (SP) state are there studies that establish its role as a vector of a pathogenic rickettsia (). The aim of the study was to analyze the genetic diversity, population dynamics, and rickettsia infection in populations from different spotted fever scenarios in Brazil. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D-loop mitochondrial markers for tick population analyses, and A, A, A, and B genes for rickettsia researches. Of the 7-17 tick haplotypes identified, 5-13 were exclusive to each population and 2-12 for each epidemiological scenario, as well as three haplotypes shared by all populations. populations are expanding, and do not appear to be genetically structured vis-a-vis the different epidemiological scenarios studied. (in SP) and (in Santa Catarina) were identified as infecting . No relationship between tick haplotypes and rickettsia types were observed.
PubMed: 34578178
DOI: 10.3390/pathogens10091146 -
Infection and Immunity Nov 2021Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is an enzootic, obligate, intracellular bacterial pathogen. Nitric oxide (NO) synthesized by...
Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is an enzootic, obligate, intracellular bacterial pathogen. Nitric oxide (NO) synthesized by the inducible NO synthase (iNOS) is a potent antimicrobial component of innate immunity and has been implicated in the control of virulent spp. in diverse cell types. In this study, we examined the antibacterial role of NO on R. rickettsii. Our results indicate that NO challenge dramatically reduces R. rickettsii adhesion through the disruption of bacterial energetics. Additionally, NO-treated R. rickettsii cells were unable to synthesize protein or replicate in permissive cells. Activated, NO-producing macrophages restricted R. rickettsii infections, but inhibition of iNOS ablated the inhibition of bacterial growth. These data indicate that NO is a potent antirickettsial effector of innate immunity that targets energy generation in these pathogenic bacteria to prevent growth and subversion of infected host cells.
Topics: Energy Metabolism; Host-Pathogen Interactions; Immunity, Innate; Macrophages; Nitric Oxide; Nitric Oxide Synthase Type II; Rickettsia rickettsii; Rocky Mountain Spotted Fever
PubMed: 34491789
DOI: 10.1128/IAI.00371-21 -
Wilderness & Environmental Medicine Dec 2021Rocky Mountain spotted fever (RMSF) is a bacterial disease associated with morbidity and mortality when untreated. The primary study objectives are to describe clinician...
INTRODUCTION
Rocky Mountain spotted fever (RMSF) is a bacterial disease associated with morbidity and mortality when untreated. The primary study objectives are to describe clinician diagnostic and treatment practices in a nonendemic area after the occurrence of an unrecognized severe pediatric presumed RMSF case (index case). We hypothesized that inpatient diagnostic testing frequency and initiation of empiric treatment will increase after the index case.
METHODS
We performed a retrospective chart review of patients aged less than 18 y evaluated for RMSF at Penn State Hershey Children's Hospital between 2010 and 2019. We divided the study population into 2 groups (preindex and postindex) and evaluated patient characteristics, RMSF testing completion, and timing of doxycycline administration.
RESULTS
Fifty-four patients (14 [26%] preindex and 40 [74%] postindex) were included. Age (median [25 percentile, 75 percentile]) decreased from 14.5 y (8.6, 16) preindex to 8.3 y (3.6, 14) postindex. Twelve (86%) preindex and 31 (78%) postindex patients received empiric doxycycline (P=0.70). Four years after the index case, a decrease in empiric and urgent initiation of doxycycline administration was noted. One case of severe RMSF was diagnosed 4 y after the index case.
CONCLUSIONS
Our study found that inpatient RMSF testing increased after the index case, but not all patients received empiric treatment. This may represent an underappreciation of RMSF severity even after a recent devastating case. We suggest that when severe rare but possibly reversible diseases, such as RMSF occur, all clinicians are educated on the diagnostic and treatment approach to reduce the morbidity and mortality risk.
Topics: Child; Doxycycline; Humans; Retrospective Studies; Rocky Mountain Spotted Fever; Schools
PubMed: 34391635
DOI: 10.1016/j.wem.2021.05.005 -
The American Journal of Tropical... Aug 2021This study aimed to analyze epidemiological indicators related to seroprevalent and seroincident cases of spotted fever group rickettsiae (SFGR) and to identify housing...
This study aimed to analyze epidemiological indicators related to seroprevalent and seroincident cases of spotted fever group rickettsiae (SFGR) and to identify housing conditions related to tick infestation. A prospective study (2016-2018) was conducted to examine rickettsial seropositivity in humans, domestic animals, and wild mammals in the municipality of Uramita, Antioquia, Colombia, where a previous Rickettsia rickettsii outbreak was reported from 2014 to 2015. The seroprevalence and its associated factors were estimated at baseline, and the seroincidence and its risk factors for humans were estimated 20 months later. A cross-sectional analysis was performed to evaluate the housing conditions linked to tick infestation. The SFGR seroprevalence was 26.70% (95% confidence interval [CI], 20.79-31.37), and the factors associated with SFGR seropositivity were male sex (adjusted prevalence ratio [PRa], 1.67; 95% CI, 1.19-2.32), age (evaluated in 5-year increments) (PRa, 1.05; 95% CI, 1.01-1.09), and household proximity (PRascattered vs. very near=3.87; 95% CI, 1.12-8.66). The overall seroincidence was 7.40% (95% CI, 4.71-11.06), and the factors associated with SFGR seroincident cases were the presence of wild animals (adjusted relative risk [RRa], 2.46; 95% CI, 1.06-4.72) and the presence of trees in the peri-domiciliary area (RRa, 0.47; 95% CI, 0.23-0.94). The prevalence of house tick infestation was 27.81% (95% CI, 21.93-34.80), and the factors associated with infestation were dirt floors (PRa, 5.88; 95% CI, 2.28-10.31), fiber cement roofs (PRa, 1.76; 95% CI, 1.07-2.83), and the presence of canines in peri-domiciliary or intra-domiciliary areas (PRa, 5.05; 95% CI, 3.31-7.19). Seropositivity rates for canines and opossums were 35.62% (26/73) and 100% (6/6), respectively. Identification of these factors will help to implement efficient surveillance programs in Colombia.
Topics: Adult; Animals; Animals, Wild; Colombia; Dogs; Female; Housing; Humans; Male; Middle Aged; Opossums; Prospective Studies; Rickettsia Infections; Seroepidemiologic Studies; Tick Infestations; Ticks; Young Adult
PubMed: 34370699
DOI: 10.4269/ajtmh.20-0104 -
Acta Tropica Nov 2021On May 2, 2017, an outbreak of unexplained fever with rashes was reported in Lu'an, China. In this study, we aimed to identify the possible pathogens, epidemiological...
OBJECTIVE
On May 2, 2017, an outbreak of unexplained fever with rashes was reported in Lu'an, China. In this study, we aimed to identify the possible pathogens, epidemiological characteristics, and risk factors of this outbreak.
METHODS
We conducted descriptive field epidemiological studies. Blood samples were tested using an indirect immunofluorescence assay for Rickettsia rickettsii antibody, and nested polymerase chain reaction and gene sequencing assays were performed.
RESULTS
We recruited 39 cases who had symptomatic onset from April 20 to June 8, 2017. Among these, 9 were suspected cases, 18 were probable cases, and 12 were confirmed cases. No one died. The main clinical manifestations were fever (100%), rash (100%), fatigue (97.3%), myalgia (83.8%), and anorexia (83.8%). None of the patients died. Thirty-seven patients who were treated with antibiotics during hospitalization showed significant improvement. The cases were distributed across 14 townships in 2 counties. The median age was 59 (43.0-81.0) years, of which 93.3% had a history of tea picking (28/30), and 77.3% (17/22) had a history of tick bites. The mean incubation period was 5.0 days (2.0-13.0 days). Serum IgG titers were higher in convalescent patients than in the general population (p = 0.016). Phylogenetic analysis revealed that the ompA sequences of Rickettsia sp. Lu'an-2018 had an 86.8%-99.0% sequence identity with the 23 strains of Rickettsia found worldwide.
CONCLUSIONS
This was the first reported outbreak of an undetermined species of a human infection with the spotted fever group of Rickettsia in China, which might be caused by ticks biting local residents when picking tea.
Topics: Adult; Aged; Aged, 80 and over; Animals; Bites and Stings; China; Disease Outbreaks; Humans; Middle Aged; Phylogeny; Rickettsia; Rocky Mountain Spotted Fever; Ticks
PubMed: 34358513
DOI: 10.1016/j.actatropica.2021.106072