Tick Pools Research Articles

The bacterial patterns suggesting the dynamic features of tick-associated microorganisms in hard ticks

BackgroundTicks are blood-feeding significant arthropods that can harbour various microorganisms, including pathogens that pose health risks to humans and animals. Tick-symbiont microorganisms are believed to influence tick development, but the intricate interactions between these microbes and the relationships between different tick-borne microorganisms remain largely unexplored.ResultsBased on 111 tick pool samples presenting questing and engorged statuses including 752 questing tick and 1083 engorged tick from cattle and goats, which were collected in two types of geographic landscape (semi-desert and alpine meadow). We observed significant variations in the composition of tick-borne microorganisms across different environments and blood-engorgement statuses, with a pronounced divergence in symbionts compared to environmental bacteria. Metabolic predictions revealed over 90 differential pathways for tick-borne microorganisms in distinct environments and more than 80 metabolic variations in response to varying blood engorgement statuses. Interestingly, nine pathways were identified, particularly related to chorismate synthesis and carbohydrate metabolism. Moreover, microbial network relationships within tick-borne microorganism groups were highly distinct across different environments and blood-engorgement statuses. The microbial network relationships of symbionts involve some pathogenic and environmental microorganisms. Regression modelling highlighted positive correlations between the Coxiella symbiont and related pathogens, while some environmental bacteria showed strong negative correlations with Coxiella abundance. We also identified commensal bacteria/pathogens in bacterial cooccurrence patterns. Furthermore, we tested pathogenic microorganisms of each tick sample analysis revealed that 86.36% (1601/1855) of the tick samples carried one or more pathogenic microorganisms, The total carrier rate of bacterial pathogens was 43.77% ((812/1855). Most blood samples carried at least one pathogenic microorganism. The pathogens carried by the ticks have both genus and species diversity, and Rickettsia species are the most abundant pathogens among all pathogens.ConclusionOur findings underscore that the bacterial pattern of ticks is dynamic and unstable, which is influenced by the environment factors and tick developmental characteristics.

Occurrence of Coxiella burnetii in wild lagomorphs and their ticks in Spanish Mediterranean ecosystems.

Coxiella burnetii, the causative agent of Q fever, is a zoonotic multi-host vector-borne pathogen of major public health importance. Although the European Food Safety Authority has recently made the monitoring of this bacterium in wildlife a priority, the role of wild lagomorphs in the transmission and maintenance of C. burnetii is poorly understood. The aims of this study were to determine the prevalence and risk factors associated with C. burnetii circulation in European wild rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis) and to assess the presence of this pathogen in ticks that feed on them in Mediterranean ecosystems in Spain, the country with the highest number of reported cases of Q fever in Europe. A total of 574 spleen samples were collected from 453 wild rabbits and 121 Iberian hares, and 513 ticks (processed in 120 pools) between the 2017/2018 and 2021/2022 hunting seasons. C. burnetii DNA was detected in 103 (17.9%; 95% CI: 14.8-21.1) of the 574 wild lagomorphs tested. By species, prevalence was 16.3% (74/453; 95% CI: 12.9-19.7) in the European wild rabbit and 24.0% (29/121; 95% CI: 16.4-31.6) in the Iberian hare. At least one positive lagomorph was found on 47.9% of the 96 hunting estates sampled and in every hunting season since 2018/2019. Two risk factors associated with C. burnetii infection were as follows: outbreak of myxomatosis on the hunting estate in the month prior to sampling and high tick abundance observed by gamekeepers on the hunting estate. C. burnetii DNA was also found in 33 of the 120 (27.5%; 95% CI: 19.5-35.5) tick pools tested. The pathogen was detected in 66.7% (4/6), 29.2% (26/89) and 21.4% (3/14) of Haemaphysalis hispanica, Rhipicephalus pusillus and Hyalomma lusitanicum pools respectively. This study provides new epidemiological data on C. burnetii in European wild rabbits and is the first survey on this zoonotic pathogen performed in Iberian hares. Our results indicate widespread endemic circulation of C. burnetii and highlight the importance of both wild lagomorph species as natural reservoirs of this zoonotic bacterium in Mediterranean ecosystems in southern Spain, which may be of public and animal health concern. The high prevalence and wide diversity of positive tick species suggest the possible role of ticks in the epidemiological cycle of C. burnetii, with the potential risk of transmission to sympatric species, including humans.

Coxiella burnetii serostatus in dromedary camels (Camelus dromedarius) is associated with the presence of C. burnetii DNA in attached ticks in Laikipia County, Kenya

AbstractAimsQ fever is a globally distributed, neglected zoonotic disease of conservation and public health importance, caused by the bacterium Coxiella burnetii. Coxiella burnetii normally causes subclinical infections in livestock, but may also cause reproductive pathology and spontaneous abortions in artiodactyl species. One such artiodactyl, the dromedary camel (Camelus dromedarius), is an increasingly important livestock species in semi‐arid landscapes. Ticks are naturally infected with C. burnetii worldwide and are frequently found on camels in Kenya. In this study, we assessed the relationship between dromedary camels' C. burnetii serostatus and whether the camels were carrying C. burnetii PCR‐positive ticks in Kenya. We hypothesized that there would be a positive association between camel seropositivity and carrying C. burnetii PCR‐positive ticks.Methods and ResultsBlood was collected from camels (N = 233) from three herds, and serum was analysed using commercial ELISA antibody test kits. Ticks were collected (N = 4354), divided into pools of the same species from the same camel (N = 397) and tested for C. burnetii and Coxiella‐like endosymbionts. Descriptive statistics were used to summarize seroprevalence by camel demographic and clinical variables. Univariate logistic regression analyses were used to assess relationships between serostatus (outcome) and tick PCR status, camel demographic variables, and camel clinical variables (predictors). Camel C. burnetii seroprevalence was 52%. Across tick pools, the prevalence of C. burnetii was 15% and Coxiella‐like endosymbionts was 27%. Camel seropositivity was significantly associated with the presence of a C. burnetii PCR‐positive tick pool (OR: 2.58; 95% CI: 1.4–5.1; p = 0.0045), increasing age class, and increasing total solids.ConclusionsThe role of ticks and camels in the epidemiology of Q fever warrants further research to better understand this zoonotic disease that has potential to cause illness and reproductive losses in humans, livestock, and wildlife.

RNA viromes of Dermacentor nuttalli ticks reveal a novel uukuvirus in Qīnghăi Province, China

Ticks are a major parasite on the Qīnghăi-Tibet Plateau, western China, and represent an economic burden to agriculture and animal husbandry. Despite research on tick-borne pathogens that threaten humans and animals, the viromes of dominant tick species in this area remain unknown. In this study, we collected Dermacentor nuttalli ticks near Qīnghăi Lake and identified 13 viruses belonging to at least six families through metagenomic sequencing. Four viruses were of high abundance in pools, including Xīnjiāng tick-associated virus 1 (XJTAV1), and three novel viruses: Qīnghăi Lake virus 1, Qīnghăi Lake virus 2 (QHLV1, and QHLV2, unclassified), and Qīnghăi Lake virus 3 (QHLV3, genus Uukuvirus of family Phenuiviridae in order Bunyavirales), which lacks the M segment. The minimum infection rates of the four viruses in the tick groups were 8.2%, 49.5%, 6.2%, and 24.7%, respectively, suggesting the prevalence of these viruses in D. ​nuttalli ticks. A putative M segment of QHLV3 was identified from the next-generation sequencing data and further characterized for its signal peptide cleavage site, N-glycosylation, and transmembrane region. Furthermore, we probed the L, M, and S segments of other viruses from sequencing data of other tick pools by ​using the putative M segment sequence of QHLV3. By revealing the viromes of D. nuttalli ticks, this study enhances our understanding of tick-borne viral communities in highland regions. The putative M segment identified in a novel uukuvirus suggests that previously identified uukuviruses without M segments should have had the same genome organization as typical bunyaviruses. These findings will facilitate virus discovery and our understanding of the phylogeny of tick-borne uukuviruses.

First detection of Ehrlichia chaffeensis, Ehrlichia canis, and Anaplasma ovis in Rhipicephalus bursa ticks collected from sheep, Turkey.

Anaplasmosis and ehrlichiosis are important tick-borne rickettsial diseases of medical and veterinary importance that cause economic losses in livestock. In this study, the prevalence of Anaplasma ovis, Ehrlichia canis and Ehrlichia chaffeensis was investigated in ticks collected from sheep in various farms in Van province, which is located in the Eastern Anatolian Region of Turkey. The ticks used in this study were collected by random sampling in 26 family farm business in 13 districts of Van province. A total of 688 ticks were collected from 88 sheep and 88 tick pools were created. All ticks identified morphologically as Rhipicephalus bursa. Phylogenetic analysis of Chaperonin and 16S rRNA gene sequences confirmed A. ovis, E. canis and E. chaffeensis in this study. Of the 88 tick pools tested, 28.41% (25/88) were positive for at least one pathogen. Anaplasma DNA was detected in five of the 88 pools (5.68%), E. canis DNA was detected in 19 of the 88 pools (21.59%), and E. chaffeensis DNA was detected in one of the 88 pools (1.14%) of R. bursa ticks. To our knowledge, this is the first report describing the presence of A. ovis, E. canis, and E. chaffeensis in R. bursa ticks collected from sheep in Turkey. Further studies are needed to investigate other co-infections in sheep in Turkey.

Science abhors a surveillance vacuum: Detection of ticks and tick-borne pathogens in southern New Mexico through passive surveillance.

Robust tick surveillance enhances diagnosis and prevention of tick-borne pathogens, yet surveillance efforts in the United States are highly uneven, resulting in large surveillance vacuums, one of which spans the state of New Mexico. As part of a larger effort to fill this vacuum, we conducted both active and passive tick sampling in New Mexico, focusing on the southern portion of the state. We conducted active tick sampling using dragging and CO₂ trapping at 45 sites across Hidalgo, Doña Ana, Otero, and Eddy counties between June 2021 to May 2022. Sampling occurred intermittently, with at least one sampling event each month from June to October 2021, pausing in winter and resuming in March through May 2022. We also conducted opportunistic, passive tick sampling in 2021 and 2022 from animals harvested by hunters or captured or collected by researchers and animals housed in animal hospitals, shelters, and farms. All pools of ticks were screened for Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommatis, Ehrlichia ewingii, and Ehrlichia chaffeensis. Active sampling yielded no ticks. Passive sampling yielded 497 ticks comprising Carios kelleyi from pallid bats, Rhipicephalus sanguineus from dogs, mule deer, and Rocky Mountain elk, Otobius megnini from dogs, cats, horses, and Coues deer, Dermacentor parumapertus from dogs and black-tailed jackrabbits, Dermacentor albipictus from domesticated cats, mule deer and Rocky Mountain elk, and Dermacentor spp. from American black bear, Rocky Mountain elk, and mule deer. One pool of D. parumapterus from a black-tailed jackrabbit in Luna County tested positive for R. parkeri, an agent of spotted fever rickettsiosis. Additionally, a spotted fever group Rickettsia was detected in 6 of 7 C. kelleyi pools. Two ticks showed morphological abnormalities; however, these samples did not test positive for any of the target pathogens, and the cause of the abnormalities is unknown. Passive surveillance yielded five identified species of ticks from three domestic and six wild mammal species. Our findings update tick distributions and inform the public, medical, and veterinary communities of the potential tick-borne pathogens present in southern New Mexico.

Molecular identification of Borrelia and SFG Rickettsia spp. in hard ticks parasitizing domestic and wild animals in southeastern Spain

Lyme disease and the spotted fever group rickettsiosis, involve bacteria belonging to the genus Borrelia and Rickettsia, respectively. These infections are the most important tick-borne zoonotic diseases involving ticks as vectors. Descriptive and epidemiological studies are essential to determine the animal hosts involved in the maintenance of these diseases. In the present study, 94 tick pool samples from 15 different host species located in the Region of Murcia (southeastern, Spain) were analysed. Ticks were morphologically identified as: Dermacentor marginatus, Hyalomma lusitanicum, Ixodes Ricinus, and Rhipicephalus sanguineus. Our results showed that 5.3% of the tick pool samples carried Borrelia spp. DNA, and 20.2% carried SFG Rickettsia DNA. In every hard tick pool Spot Fever Group (SFG) Rickettsia spp. DNA were detected, except for H. lusitanicum. Likewise, D. marginatum was the only species in which Borrelia spp. DNA was not detected. Barbary sheep and wild boar were the host species in which tick pools showed DNA presence of both pathogens. This study increases the knowledge about the presence of Borrelia spp. DNA and SFG Rickettsia spp. DNA in different hard tick species from this geographical area.

Detection of Brucella in Dermacentor Ticks of Wild Boar with Brucellosis

Brucellosis is a sanitary and economically relevant disease affecting humans, livestock, and wildlife. Ticks have been suggested as vectors, long-term carriers, and amplifiers of Brucella. In this study, ticks from wildlife ungulate hosts living in hunting reserves of a central region of Spain were collected during a 6-year period, pooled, and screened for Brucella spp. by PCR. Aiming to correlate Brucella spp. DNA presence in ticks with Brucella spp. infections in wildlife ungulate hosts, liver samples from deceased wildlife ungulates coming from the hunting reserves showing a positive result for Brucella in ticks were tested using a commercial ELISA. In total, 229 tick pools from wild boar (Sus scrofa, n = 176; 76.8%, 95% CI 70.9%–81.8%), red deer (Cervus elaphus, n = 40; 17.4%, 95% CI 13.1%–22.9%), mouflon (Ovis orientalis musimon, n = 7; 3.06%, 95% CI 1.49%–6.17%), and fallow deer (Dama dama, n = 6; 2.62%, 95% CI 1.21%–5.60%) were analyzed. PCR results showed that 3.93% (95% CI 2.08%–7.30%) tick pools (9/229) from 16.6% hunting reserves (7/41) screened yielded a positive PCR result for Brucella. All positive ticks were Dermacentor (Dermacentor marginatus or Dermacentor reticulatus) collected from wild boar. Ticks collected from wild boars were positive to Brucella in a relative percentage of 5.10% (95% CI = 1.61–11.4) in 2018 and of 7.59% (95% CI = 2.79–15.6) in 2021 (6-year prevalence of 5.17%, 9/176). ELISA showed positive results in three wild boars coming from two out of seven hunting reserves (28.5%) with a positive PCR for Brucella in ticks. To conclude, Brucella spp. DNA can be detected in Dermacentor ticks parasitizing wild boars living in hunting reserves harboring Brucella spp.-seropositive wild boars. This study provides evidence that the contribution of arthropod vectors should be considered in the epidemiology of brucellosis in wildlife.

Detection and Genetic Analysis of Songling Virus in Haemaphysalis concinna near the China-North Korea Border

Background: Songling virus (SGLV) is a spherical, enveloped, fragmented, negative-stranded RNA virus belonging to the genus Orthonairovirus in the Nairoviridae family. SGLV is transmitted by ticks and can cause disease in humans. This study identified and characterized SGLV in Haemaphysalis concinna ticks collected in 2023 in the Yanbian Korean Autonomous Prefecture (China) near the China-North Korea border. Methods: A real-time quantitative polymerase chain reaction (RT-qPCR) was used to screen for SGLV nucleic acid in ticks. Baby hamster kidney (BHK-21) and African green monkey kidney (Vero) cells were used to isolate strains of SGLV from nucleic acid-positive samples through three successive passages. Next-generation sequencing and phylogenetics methods were used to characterize the SGLVs. Results: Of the 1659 ticks collected from 6 towns in the Yanbian Korean Autonomous Prefecture near the China-North Korea border, positive SGLV nucleic acid results were identified in 19 H. concinna tick pools from Helong and Longjing towns. This discovery led to the extraction of 17 SGLV genome sequences. Homology analysis that compare the newly discovered L, M, and S segments of SGLV strain HLJ1202 revealed nucleotide similarities ranging from 95.5%–97.1%, 91.9%–98.9%, and 98.3%–99.2%, respectively, and amino acid similarities ranging from 95.7%–97.4%, 97.1%–98.8%, and 98.2%–98.9%, respectively. Six distinct clades, characterized by specific geographic locations and host organisms, were identified on the Maximum Likelihood tree of the L segment. The YB129 and YB150 isolates demonstrated SGLV nucleic acid replication across three successive passages in Vero cells, as evidenced by the decrease in RT-qPCR Ct values. Conclusion: This study marks the initial identification of SGLV in H. concinna within the Yanbian Korean Autonomous Prefecture.

The Molecular Detection of Bacterial Infections of Public Health Importance in Hard Tick (Ixodidae) Nymphs Collected from the Forest Fringes of Western Ghats in the Goa, Karnataka and Maharashtra States of India.

A survey was conducted to determine the human tick-borne bacterial infections in the nymphs which were collected from Western Ghats' fringe forest areas. Tick nymphs were collected using the flagging method from the villages where cases Kyasanur Forest Disease (KFD) were previously reported in the states of Goa, Karnataka and Maharashtra. A total of 200 tick pools consisting of 4587 nymphs were tested by PCR for the detection of bacteria of public health importance, such as Coxiella burnetii and Rickettsia spp. Of these, four pools (4.8%) in Karnataka and three pools (4.4%) in Maharashtra were positive for Coxiella burnetii, while none of the samples from Goa state were positive. Rickettsia spp. were positively obtained from Maharashtra (51.5%), Goa (35.42%) and Karnataka (26.19%). The sequence results of Rickettsia spp. showed similarity to the spotted fever group Candidatus Rickettsia shennongii, Rickettsia conorii subsp. heilongjiangensis and Rickettsia spp. strain koreansis. Individuals are entering into the forest areas for various reasons are more likely to infect with Coxiella burnetii. and Rickettsia spp.

Investigation of a cluster of acute-onset seizures and deaths among children, Sirohi District, Rajasthan, April 2022

Background: Following reports of seven deaths among children with seizure and vomiting in the village of Sirohi, Rajasthan in April 2022, an epidemiological investigation was conducted. Methods: We established a hospital-based surveillance and did active case finding. A case was defined as vomiting and acute onset seizure or altered sensorium in <18 years old in Verafalli village. We conducted verbal autopsy and collected information on food, behaviours and health-seeking. Food samples, cerebrospinal fluid (CSF) and blood specimens were collected for testing biochemical, bacterial and viral markers. Environmental surveys were conducted around cases’ houses for presence of poisonous vegetation and potential vectors. Results: Among 11 cases (median age 7 years (2-16 years), females 27%), all had vomiting, new-onset seizure was present in 73% and altered sensorium in 27%; 33% were hospitalized. Case fatality was 64%. No new cases were identified after April 2022. Median time between symptom onset and death was 9 hours (2-54 hours). Among deaths 28% (2/7) were hospitalized. Two deaths had low weight-for-age, blood glucose <25 mg/dl (refractory hypoglycemia) and elevated liver enzymes (SGPT >8000 IU/L). Lab results for food and CSF samples were inconclusive for bacterial and viral markers. Toxicology screen of one death was negative for organophosphates. In 25% (2/8), tick pools tested positive for rickettsia. All cases had houses in vicinity or within fennel crop area. Conclusions: This acute health event cluster presenting as acute seizures with rapid progression among children in a rural setting was likely due to environmental toxin consumption; high fatality may result from uncorrected metabolic derangement. Aflatoxin is commonly known to infect fennel crops. We recommend early identification and case management to prioritize metabolic derangement correction; continued surveillance and a systematic epidemiological investigation to evaluate the role of environmental toxins particularly aflatoxin as the underlying etiology for similar events in future.

Detection and characterization of zoonotic Bartonella spp. in rodents and shrews ectoparasites from Kigoma and Morogoro regions, Tanzania

Abstract Bartonellosis is a vector-borne disease which is increasingly threatening the health of humans and animals worldwide consequent to the growing wildlife-animals-human interactions. Little is known about the epidemiology of this disease in Tanzania. In this study we investigated and characterized Bartonella species in small mammals’ ectoparasites from potentially high-risk areas in the country. A total of 141 ectoparasites pools of mites, fleas, ticks, and lice were analyzed using conventional PCR and sequencing. Bartonella DNA was detected in 34.8 % of the tested ectoparasite pools, with mites at 32.9 %, fleas at 40 %, ticks at 12.5 %, and lice at 50 %. Phylogenetic analysis showed that the Bartonella spp. genotypes were closely related to those found in Uganda, Kenya, and South Africa. Different genotypes with independent haplotypes were observed, although most Bartonella spp. from fleas shared the same haplogroup. The confirmed presence of Bartonella elizabethae and Bartonella tribocorum in field and house rodents emphasizes the prevailing transmission risk of zoonotic infections in the study areas and beyond. Screening of humans, companion animals, and livestock in potentially high-risk areas in Tanzania is necessary in order to inform the development of responsive surveillance and control strategies.

Clinical, epidemiological, and molecular investigation of Kyasanur forest disease from Karnataka state, India during 2018-2019

Background In this study, we carried out an investigation of Kyasanur Forest Disease (KFD) suspected human cases reported in Karnataka state, India from December 2018 to June 2019. Methods The clinical samples of KFD suspected cases (n = 1955) from 14 districts of Karnataka were tested for KFD using real-time RT-PCR and IgM ELISA. Further, the KFD-negative samples were tested for IgM antibodies against dengue and chikungunya viruses. Monkey samples (n = 276) and tick pools (n = 11582) were also screened using real-time RT-PCR. KFD-positive samples were further analysed using next-generation sequencing along with clinico-epidemiological analysis. Results Of all, 173 (8.8%) cases tested positive for KFD either by real-time RT-PCR (n = 124), IgM ELISA (n = 53) or both tests (n = 4) from seven districts. Among KFD-negative cases, IgM antibody positivity was observed for dengue (2.6%), chikungunya (5.8%), dengue and chikungunya coinfection (3.7%). KFD cases peaked in January 2019 with fever, conjunctivitis, and myalgia as the predominant symptoms and a mortality of 4.6%. Among confirmed cases, 41% received a single dose and 20% received two doses of the KFD vaccine. Of the seven districts with KFDV positivity, Shivamogga and Hassan districts reported KFD viral RNA positivity in humans, monkeys, and ticks. Sequencing analysis of 2019 cases demonstrated a difference of less than 1.5% amino acid compared to prototype KFDV. Conclusion Although the KFD has been endemic in many districts of Karnataka state, our study confirms the presence of KFDV for the first time in two new districts, i.e. Hassan and Mysore. A comparative analysis of KFDV infection among the KFD-vaccinated and non-vaccinated populations demonstrated an insignificant difference.

Circulation of Crimean-Congo Haemorrhagic Fever Virus in Ticks in Upper Guinea-Republic of Guinea

The aim of this study was to map the distribution of agents carrying the Crimean-Congo haemorrhagic fever virus (arbovirus-tica) in the natural region of Upper Guinea. The prefectures of Kankan, Dabola and Faranah were used as collection areas. Random sampling of different types of animals was used to collect the biomaterial. Two types of analysis methods (RT-PCR and ELISA) were used. Out of a total of 578 ticks collected and divided into 254 pools, the genus Amblyomma was the most frequently encountered with 83 tick pools. Molecular analysis (RT-PCR) for the detection of virus RNA revealed 2 positive cases (0.8%). Direct enzyme-linked immunosorbent assays (ELISA) for the detection of Ag yielded only one positive case (0.4%). We found that the species Rhipicephalus geigyi was the main vector and reservoir of the pathogen in Upper Guinea.

Molecular detection of Rickettsia africae from Amblyomma hebraeum ticks in Mafikeng city of North West Province, South Africa

Rickettsia africae causes zoonotic African tick bite fever, which is a disease of “One Health” importance. There have been reported cases of tourists from Europe and Asia who have been bitten by ticks whilst visiting South Africa's nature reserves, and on their return to their countries, the display African Tick Bite Fever sickness. Hence, the aim of this study was to determine the occurrence of Rickettsia africae in Amblyomma hebraeum ticks infesting livestock in the North West Province. A total of 358 A. hebraeum ticks were collected from 60 ruminants (cattle, sheep and goats) in Mafikeng City of North West Province, South Africa. Ticks were identified morphologically and further confirmed by sequencing of their ITS2 gene. DNA was extracted from 60 pools of ticks which consisted of 5–6 adult ticks that were from the same ruminant host. Infections with Rickettsia spp. were found in 48%, 40%, and 32% of cattle, sheep, and goats, respectively, in amplification by PCR using the ompA gene. The ompA gene sequences showed that the Rickettsia spp. were identified as R. africae. Although the animals from whom the ticks were collected did not exhibit any clinical symptoms, it is well recognised that R. africae is a disease with significant zoonotic potential. Thus, it is important to use the “One Health” approach to formulate prevention and control measures for this pathogen for animal and human health as well as the tourism sector due to the ecotourism importance of the resultant disease.

Metagenomics Characterization of Ixodes ricinus Intestinal Microbiota as Major Vector of Tick-Borne Diseases in Domestic Animals.

Understanding the microbiota of disease vectors can help for developing new strategies to prevent the transmission of vector pathogens. Ixodes ricinus is one of the most notorious tick vectors with increasing importance in Iran and other parts of the world while there is limited data on its microbiota. This study aimed to use metagenomics for identifying the I. ricinus tick's microbiota of Iran. A total of 39 adult ticks were collected from Mazandaran (21 females), Gilan (17 females), and Golestan (1 male). Five tick pools prepared from 39 adults of I. ricinus were subjected to metagenomics analysis. The data were analyzed by targeting the V6 region of the 16S rRNA gene by Illumina 4000 Hiseq sequencing. Among hundreds of intestinal microbiota identified by metagenomics, various pathogenic microorganisms distributed in 30 genera and species including those responsible for tick-borne diseases resided in the genera Coxiella, Rickettsia, and Burkholderia were found. Our results indicated that metagenomics identifies bacteria genera and species which cannot be easily recognized by routine methods. The presence of such pathogenic bacteria indicates the importance of possible zoonotic diseases in this region which could affect public health. These results further substantiate the importance of advanced metagenomics analyses to identify neglected tick-borne pathogens which enable researchers to provide efficient mapping roads for the management of emerging and re-emerging infectious diseases.

Molecular investigation of Coxiella burnetii and Francisella tularensis infection in ticks in northern, western, and northwestern Iran.

Tularemia and Q fever are endemic diseases in Iran; however, little information is available on the prevalence of the causative agents, Coxiella burnetii and Francisella tularensis, in Iranian ticks. This study investigated C. burnetii and F. tularensis among hard ticks in this country. We collected ticks from livestock and other mammals in Guilan, Mazandaran, Golestan (northern Iran), Kurdistan (western Iran), and West Azerbaijan (northwestern Iran) provinces. Genomic DNA from collected ticks was extracted and screened for C. burnetii and F. tularensis using Real-time PCR. A total of 4,197 ticks (belonging to 12 different species) were collected, and Ixodes ricinus (46.4%), Rhipicephalus turanicus (25%), and Rhipicephalus sanguineus sensu lato (19.1%) were the most collected species. Of 708 pooled tick samples, 11.3% and 7.20% were positive for C. burnetii and F. tularensis, respectively. The genus of Rhipicephalus had the highest (18.3%) C. burnetii infection among the collected tick pools (P<0.001). Furthermore, the most positive pools for F. tularensis belonged to Haemaphysalis spp. (44.4%). Kurdistan had the most significant percentage of C. burnetii-infected ticks (92.5%), and there was a meaningful relationship between the provinces and the infection (P< 0.001). The ticks from Golestan exhibited the highest F. tularensis infection rate (10. 9%), and the infection showed no significant relationship with the provinces (P = 0.19). Ticks collected from grasslands had a higher Coxiella burnetii infection rate than those collected from animals (39.4% vs. 7.9%; p<0.01). However, ticks collected from animal surfaces had a slightly higher rate of Francisella tularensis infection than those collected from grasslands (7.6% vs. 3.9%; p = 0.24). Here, we demonstrated the presence of both pathogens in the north (Guilan, Mazandaran, and Golestan provinces), the west (Kurdistan province), and the northwest (West Azerbaijan province) of Iran. The public health system should pay particular attention to tick bites in veterinary medicine and humans.

First record of Babesia and Theileria parasites in ticks from Kassena-Nankana, Ghana.

Ticks are efficient vectors for transmitting pathogens that negatively affect livestock production and pose a risk to public health. In this study, Babesia and Theileria species were identified in ticks collected from cattle, sheep and goats from the Kassena-Nankana Districts of Ghana between February and December 2020. A total of 1550 ticks were collected, morphologically identified, pooled and screened for pathogens using primers that amplify a 560 bp fragment of the ssrRNA gene and Sanger sequencing. Amblyomma variegatum (62.98%) was the predominant tick species. From the 491 tick pools screened, 12/15 (2.44%) positive pools were successfully sequenced. The pathogen DNA identified were Theileria ovis in eight (15.38%) pools of Rhipicephalus evertsi evertsi, Theileria velifera in two (0.78%) pools of A. variegatum and Babesia occultans and Babesia sp. Xinjiang in one (1.72%) pool each of Hyalomma truncatum. It was further observed that T. ovis occurred in ticks collected from only sheep (p < 0.001) which were females (p = 0.023) and < =1 year old (p = 0.040). This study reports the first identification of these pathogens in ticks within Kassena-Nankana. With the constant trade of livestock, there is a need for effective tick control measures to prevent infection spread.

Molecular Detection of Tacheng Tick Virus-1 (TcTV-1) and Jingmen Tick Virus in Ticks Collected from Wildlife and Livestock in Turkey: First Indication of TcTV-1 Beyond China.

Background: Jingmen tick virus (JMTV) and Tacheng tick virus-1 (TcTV-1) are emerging tick-borne viruses that have been recently confirmed to be etiological agents of human disease in China. However, the ecology of JMTV and TcTV-1, especially their association with ticks in wildlife and livestock, remains largely unknown in Turkey. Materials and Methods: Eight hundred thirty-two tick specimens in 117 pools were collected in Turkey between 2020 and 2022 from wildlife (Miniopterus schreibersii and Rhinolophus hipposideros; n = 10, 1.2%; Testudo graeca; n = 50, 6%) and livestock (Ovis aries and Capra aegagrus hircus; n = 772, 92.7%). The specimens were individually screened for JMTV and TcTV-1 using nRT-PCR assays targeting the partial genes. Results: JMTV was detected in one Ixodes simplex pool and two Rhipicephalus bursa pools collected from central and Aegean provinces, respectively. TcTV-1 was identified in five Hyalomma aegyptium pools collected in Mediterranean provinces. No coinfection was detected in the tick pools. Maximum likelihood analysis of JMTV partial segment 1 sequences reveal that these sequences form a separate cluster together with viruses previously characterized in Turkey and the Balkan Peninsula. The phylogenetic analysis of the TcTV-1 nucleocapsid sequences indicates that they are closely related to viruses in ticks, sheep, cattle, and humans in China, but form a separate group among themselves. Conclusion: This study provides the first molecular evidence of TcTV-1 in Hy. aegyptium in Turkey. In addion, these findings indicate that JMTV and TcTV-1 extend ticks species and geographic distributions. Thus, multiregional surveillance in livestock and wildlife is needed to evaluate potential tick vectors and the human health impact of these viruses in Turkey.

Wide distribution of Mediterranean and African spotted fever agents and the first identification of Israeli spotted fever agent in ticks in Uganda.

Rickettsia microorganisms are causative agents of several neglected emerging infectious diseases in humans transmitted by arthropods including ticks. In this study, ticks were collected from four geographical regions of Uganda and pooled in sizes of 1-179 ticks based on location, tick species, life stage, host, and time of collection. Then, they were tested by real-time PCR for Rickettsia species with primers targeting gltA, 17kDa and ompA genes, followed by Sanger sequencing of the 17kDa and ompA genes. Of the 471 tick pools tested, 116 (24.6%) were positive for Rickettsia spp. by the gltA primers. The prevalence of Rickettsia varied by district with Gulu recording the highest (30.1%) followed by Luwero (28.1%) and Kasese had the lowest (14%). Tick pools from livestock (cattle, goats, sheep, and pigs) had the highest positivity rate, 26.9%, followed by vegetation, 23.1%, and pets (dogs and cats), 19.7%. Of 116 gltA-positive tick pools, 86 pools were positive using 17kDa primers of which 48 purified PCR products were successfully sequenced. The predominant Rickettsia spp. identified was R. africae (n = 15) in four tick species, followed by R. conorii (n = 5) in three tick species (Haemaphysalis elliptica, Rhipicephalus appendiculatus, and Rh. decoloratus). Rickettsia conorii subsp. israelensis was detected in one tick pool. These findings indicate that multiple Rickettsia spp. capable of causing human illness are circulating in the four diverse geographical regions of Uganda including new strains previously known to occur in the Mediterranean region. Physicians should be informed about Rickettsia spp. as potential causes of acute febrile illnesses in these regions. Continued and expanded surveillance is essential to further identify and locate potential hotspots with Rickettsia spp. of concern.