Severe Rhipicephalus sanguineus tick infestation in a home from rural area of Nanchang in China

On October 13, 2021, a tick infestation occurred in a home in rural area of Nanchang city, China, and we were asked to inspect the tick infestation. Ticks were collected in the largest number on courtyard door jambs, followed by living room and bedroom door jambs. Ticks were identified morphologically as Rhipicephalus sanguineus adults. The 16S rRNA analysis effectively distinguished the ticks in this study from other Rhipicephalus species, including R. sanguineus south-east, temperate and tropical lineages and identified genetically as R. sanguineus south China lineage. Tick samples were subjected to conventional PCR analysis and detected negative for the presence of tick-borne pathogens. Our findings indicate that there was low transmission risk of tick-borne pathogens to humans in the tick-infested home. Further studies are needed to proactively investigate the tick species in Nanchang, and determine the presence of tick-borne pathogens for assessing their threat to human health in the region.     

Ticks (Acari: Ixodida) infesting humans in the provinces of Kelkit Valley, a Crimean-congo hemorrhagic fever endemic region in Turkey

Ticks are mandatory blood feeding ectoparasites leading transmission of various tick-borne pathogens to human and animals. Since 2002, thousands of human tick bites and numerous Crimean-Congo Hemorrhagic Fever cases have been reported in several provinces in the Kelkit Valley region in Turkey. Despite increased cases of tick bites and tick-borne diseases, no taxonomic information is available about the tick species infesting humans in the region. In the present study, a tick survey on humans was performed to determine the species composition of ticks infesting humans in several provinces of Kelkit Valley. In the survey, 1,460 ticks (721 males, 516 females and 223 nymphs) were collected from tick-infested humans. A total of 19 tick species have been found on humans in the region, including 7 Hyalomma, 2 Argas, 2 Haemaphysalis, 2 Ixodes, Dermacentor and 3 Rhipicephalus species. Infestation of Dermacentor reticulatus on humans was documented for the first time in Turkey.     

Molecular Detection of Tick-Borne Pathogens in Humans with Tick Bites and Erythema Migrans,in the Netherlands

BackgroundTick-borne diseases are the most prevalent vector-borne diseases in Europe. Knowledge on the incidence and clinical presentation of other tick-borne diseases than Lyme borreliosis and tick-borne encephalitis is minimal, despite the high human exposure to these pathogens through tick bites. Using molecular detection techniques, the frequency of tick-borne infections after exposure through tick bites was estimated.MethodsTicks, blood samples and questionnaires on health status were collected from patients that visited their general practitioner with a tick bite or erythema migrans in 2007 and 2008. The presence of several tick-borne pathogens in 314 ticks and 626 blood samples of this cohort were analyzed using PCR-based methods. Using multivariate logistic regression, associations were explored between pathogens detected in blood and self-reported symptoms at enrolment and during a three-month follow-up period.ResultsHalf of the ticks removed from humans tested positive for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, Borrelia miyamotoi and several Babesia species. Among 92 Borrelia burgdorferi s. l. positive ticks, 33% carried another pathogen from a different genus. In blood of sixteen out of 626 persons with tick bites or erythema migrans, DNA was detected from Candidatus Neoehrlichia mikurensis (n = 7), Anaplasma phagocytophilum (n = 5), Babesia divergens (n = 3), Borrelia miyamotoi (n = 1) and Borrelia burgdorferi s. l. (n = 1). None of these sixteen individuals reported any overt symptoms that would indicate a corresponding illness during the three-month follow-up period. No associations were found between the presence of pathogen DNA in blood and; self-reported symptoms, with pathogen DNA in the corresponding ticks (n = 8), reported tick attachment duration, tick engorgement, or antibiotic treatment at enrolment.ConclusionsBased on molecular detection techniques, the probability of infection with a tick-borne pathogen other than Lyme spirochetes after a tick bite is roughly 2.4%, in the Netherlands. Similarly, among patients with erythema migrans, the probability of a co-infection with another tick-borne pathogen is approximately 2.7%. How often these infections cause disease symptoms or to what extend co-infections affect the course of Lyme borreliosis needs further investigations.     

Diversity of Rickettsiales in the Microbiome of the Lone Star Tick,Amblyomma americanum

Ticks are important vectors for many emerging pathogens. However, they are also infected with many symbionts and commensals, often competing for the same niches. In this paper, we characterize the microbiome of Amblyomma americanum (Acari: Ixodidae), the lone star tick, in order to better understand the evolutionary relationships between pathogens and nonpathogens. Multitag pyrosequencing of prokaryotic 16S rRNA genes (16S rRNA) was performed on 20 lone star ticks (including males, females, and nymphs). Pyrosequencing of the rickettsial sca0 gene (also known as ompA or rompA) was performed on six ticks. Female ticks had less diverse microbiomes than males and nymphs, with greater population densities of Rickettsiales. The most common members of Rickettsiales were “Candidatus Rickettsia amblyommii” and “Candidatus Midichloria mitochondrii.” “Ca. Rickettsia amblyommii” was 2.6-fold more common in females than males, and there was no sequence diversity in the sca0 gene. These results are consistent with a predominantly vertical transmission pattern for “Ca. Rickettsia amblyommii.”     

Comparison of tick-borne microorganism communities in Ixodes spp. of the Ixodes ricinus species complex at distinct geographical regions

Characterizing the tick-borne microorganism communities of Ixodes ricinus (sheep tick) and Ixodes persulcatus (taiga tick) from the I. ricinus species complex in distinct geographical regions of Eastern Europe and European Russia, we demonstrated differences between the two ticks. Taiga ticks were more frequently mono- and co-infected than sheep ticks: 24.4 % (45/184 tested ticks) versus 17.5 % (52/297) and 4.3 % (8/184) versus 3.4 % (10/297), respectively. Ginsberg co-infection index values were significant at the various sites. Diversity of the tick-borne microorganism communities was estimated by the Shannon index, reaching values of 1.71 ± 0.46 and 1.20 ± 0.15 at the sheep-tick and the taiga-tick harbored sites, respectively. Richness of the tick-borne microorganism community in the sheep tick collection sites was about twice the value of the taiga tick collection sites. Future investigations are warranted to further characterize the peculiarities of the tick-borne microorganism communities among the ticks of the Ixodes ricinus complex.     

Prevalence and Genotypes of Anaplasma Species and Habitat Suitability for Ticks in a Mediterranean Ecosystem

Anaplasma species are tick-transmitted pathogens that impact veterinary and human health. Sicily is one of the locations where these pathogens are endemic. Sicily represents a typical Mediterranean ecosystem to study Anaplasma infection and tick habitat suitability. The aims of this study were (i) to characterize by 16S rRNA and species-specific msp4 gene PCR the prevalence and genotypes of A. marginale, A. phagocytophilum, and A. ovis in the most abundant host species in Sicilian provinces and (ii) to correlate differences between hosts and between western and eastern Sicily with the habitat suitability for ticks in these regions. Differences were found in the prevalence of Anaplasma spp. between different hosts and between western and eastern provinces. The differences in Anaplasma prevalence between different hosts may be explained by pathogen host tropism. The differences between western and eastern provinces correlated with the tick habitat suitability in these regions. The analysis of Anaplasma genotypes suggested a higher host and regional specificity for A. phagocytophilum than for A. marginale and A. ovis strains, a finding probably associated with the broader host range of A. phagocytophilum. The presence of identical A. marginale genotypes in the two regions may reflect cattle movement. The results for A. ovis suggested the possibility of some genotypes being host specific. These results provide information potentially useful for the management of tick-borne diseases caused by Anaplasma spp. in Sicily and other Mediterranean regions and may contribute to the development of models to predict the risks for these tick-borne pathogens.     

Molecular analysis of tick-borne protozoan and rickettsial pathogens in small ruminants from two South African provinces

Tick-borne protozoan and rickettsial diseases are a major threat to livestock in tropical and sub-tropical regions of Africa. In this study we investigated the presence and distribution of Theileria spp., Babesia ovis, Anaplasma ovis, Anaplasma phagocytophilum, Ehrlichia ruminantium and SFG Rickettsia in sheep and goats from Free State and KwaZulu-Natal provinces. A total of 91 blood samples were screened in this study, 61 from goats and 30 from sheep. PCR assay was conducted using primers based on Theileria spp. 18S rRNA, Babesia ovis (BoSSU rRNA), Anaplasma ovis (AoMSP4), Anaplasma phagocytophilum epank1, Ehrlichia ruminantium pCS20 and SFG Rickettsia OmpA. Overall infection rates of Theileria spp., Anaplasma ovis and Ehrlichia ruminantium were 18 (19.8%), 33 (36.3%) and 13 (14.3%), respectively. The co-infection of two pathogens were detected in 17/91 (18.7%) of all samples, goats having higher rates of co-infection compared to sheep. Phylogenetic tree analysis sequence of pCS20 gene of E. ruminantium of this study was found to be in the same clade with Kumm2 and Riverside strains both from South Africa. The phylogram of SSU rRNA of Theileria ovis had longer branch length compared to all other sequences most of which were from Asia and Middle East. This study provides important data for understanding the tick-borne diseases occurrence in the study area and it is expected to improve the approach for the diagnosis and control of these diseases.     

Isolation and Identification of Rickettsia massiliae from Rhipicephalus sanguineus Ticks Collected in Arizona

Twenty Rhipicephalus sanguineus ticks collected in eastern Arizona were tested by PCR assay to establish their infection rate with spotted fever group rickettsiae. With a nested PCR assay which detects a fragment of the Rickettsia genus-specific 17-kDa antigen gene (htrA), five ticks (25%) were found to contain rickettsial DNA. One rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of Vero E6 monkey kidney cells and XTC-2 clawed toad cells, and its cell culture and genotypic characteristics were determined. Fragments of the 16S rRNA, GltA, rOmpA, rOmpB, and Sca4 genes had 100%, 100%, 99%, 99%, and 99%, respectively, nucleotide similarity to Rickettsia massiliae strain Bar29, previously isolated from R. sanguineus in Catalonia, Spain (L. Beati et al., J. Clin. Microbiol. 34:2688-2694, 1996). The new isolate, AZT80, does not elicit cytotoxic effects in Vero cells and causes a persistent infection in XTC-2 cells. The AZT80 strain is susceptible to doxycycline but resistant to rifampin and erythromycin. Whether R. massiliae AZT80 is pathogenic or infectious for dogs and humans or can cause seroconversion to spotted fever group antigens in the United States is unknown.     

Molecular detection of pathogens from ectoparasites recovered from peri-domestic animals,and the first description of a Candidatus Midichloria sp. from Haemaphysalis wellingtoni from rural communities in Malaysia

Rural communities in Malaysia have been shown to be exposed to Coxiella, Borrelia and rickettsial infections in previous seroprevalence studies. Further research is necessary to identify the actual causative agents and the potential vectors of these infections. The arthropods parasitizing peri-domestic animals in these communities may serve as the vector in transmitting arthropod-borne and zoonotic agents to the humans.Molecular screening of bacterial and zoonotic pathogens from ticks and fleas collected from dogs, cats and chickens from six rural communities in Malaysia was undertaken. These communities were made up of mainly the indigenous people of Malaysia, known as the Orang Asli, as well as settlers in oil palm plantations. The presence of Coxiella burnetii, Borrelia, and rickettsial agents, including Rickettsia and Anaplasma, was investigated by performing polymerase chain reaction (PCR) and DNA sequencing.Candidatus Rickettsia senegalensis was detected in one out of eight pools of Ctenocephalides felis fleas. A relapsing fever group Borrelia sp. was identified from one of seven Haemaphysalis hystricis ticks tested. The results from the PCR screening for Anaplasma unexpectedly revealed the presence of Candidatus Midichloria sp., a potential tick endosymbiont, in two out of fourteen Haemaphysalis wellingtoni ticks tested. C. burnetii was not detected in any of the samples tested.The findings here provide evidence for the presence of potentially novel strains of rickettsial and borrelial agents in which their impact on public health risks among the rural communities in Malaysia merit further investigation. The detection of a potential endosymbiont of ticks also suggest that the presence of tick endosymbionts in the region is not fully explored.     

Survey of Ixodes pacificus Ticks in California Reveals a Diversity of Microorganisms and a Novel and Widespread Anaplasmataceae Species

Ixodes pacificus ticks can harbor a wide range of human and animal pathogens. To survey the prevalence of tick-borne known and putative pathogens, we tested 982 individual adult and nymphal I. pacificus ticks collected throughout California between 2007 and 2009 using a broad-range PCR and electrospray ionization mass spectrometry (PCR/ESI-MS) assay designed to detect a wide range of tick-borne microorganisms. Overall, 1.4% of the ticks were found to be infected with Borrelia burgdorferi, 2.0% were infected with Borrelia miyamotoi and 0.3% were infected with Anaplasma phagocytophilum. In addition, 3.0% were infected with Babesia odocoilei. About 1.2% of the ticks were co-infected with more than one pathogen or putative pathogen. In addition, we identified a novel Anaplasmataceae species that we characterized by sequencing of its 16S rRNA, groEL, gltA, and rpoB genes. Sequence analysis indicated that this organism is phylogenetically distinct from known Anaplasma species with its closest genetic near neighbors coming from Asia. The prevalence of this novel Anaplasmataceae species was as high as 21% at one site, and it was detected in 4.9% of ticks tested statewide. Based upon this genetic characterization we propose that this organism be called ‘Candidatus Cryptoplasma californiense’. Knowledge of this novel microbe will provide awareness for the community about the breadth of the I. pacificus microbiome, the concept that this bacterium could be more widely spread; and an opportunity to explore whether this bacterium also contributes to human or animal disease burden.     

Detection of Anaplasma bovis in an undescribed tick species collected from the eastern rock sengi Elephantulus myurus

Ticks are important vectors of numerous pathogens causing illness, fatalities, and economic loss worldwide. Infectious disease episodes are increasing, and novel tick-borne pathogens are described frequently. Identification of novel reservoir hosts and vectors of tick-borne pathogens is essential if control measures are to be successful. In South Africa, the eastern rock sengi, Elephantulus myurus , hosts a number of tick species of veterinary importance. Despite this, there remains a paucity of information regarding the tick fauna of this species, the pathogen associations of ticks that it hosts, and its role as a reservoir host of tick-borne pathogens. The current study documents the tick fauna of E. myurus and sympatric small mammal species in Limpopo Province, South Africa. The pathogen associations of ticks hosted by elephant shrews were also investigated by PCR screening of engorged nymphs for a broad range of bacterial and protozoan tick-borne infections, including Borrelia burgdorferi sensu lato and members of Apicomplexa and the order Rickettsiales. There were marked differences in tick species and abundance among host species. Elephantulus myurus was heavily, and predominantly, parasitized by an as-yet undescribed tick species that we identify as Rhipicephalus sp. near warburtoni. PCR and sequence analysis revealed the presence of Anaplasma bovis in this tick species, which may have consequences for livestock production and conservation efforts in the area where this tick species occurs.     

Influence of the Biotope on the Tick Infestation of Cattle and on the Tick-Borne Pathogen Repertoire of Cattle Ticks in Ethiopia

Background

The majority of vector-borne infections occur in the tropics, including Africa, but molecular eco-epidemiological studies are seldom reported from these regions. In particular, most previously published data on ticks in Ethiopia focus on species distribution, and only a few molecular studies on the occurrence of tick-borne pathogens or on ecological factors influencing these. The present study was undertaken to evaluate, if ticks collected from cattle in different Ethiopian biotopes harbour (had access to) different pathogens.

Methods

In South-Western Ethiopia 1032 hard ticks were removed from cattle grazing in three kinds of tick biotopes. DNA was individually extracted from one specimen of both sexes of each tick species per cattle. These samples were molecularly analysed for the presence of tick-borne pathogens.

Results

Amblyomma variegatum was significantly more abundant on mid highland, than on moist highland. Rhipicephalus decoloratus was absent from savannah lowland, where virtually only A. cohaerens was found. In the ticks Coxiella burnetii had the highest prevalence on savannah lowland. PCR positivity to Theileria spp. did not appear to depend on the biotope, but some genotypes were unique to certain tick species. Significantly more A. variegatum specimens were rickettsia-positive, than those of other tick species. The presence of rickettsiae (R. africae) appeared to be associated with mid highland in case of A. variegatum and A. cohaerens. The low level of haemoplasma positivity seemed to be equally distributed among the tick species, but was restricted to one biotope type.

Conclusions

The tick biotope, in which cattle are grazed, will influence not only the tick burden of these hosts, but also the spectrum of pathogens in their ticks. Thus, the presence of pathogens with alternative (non-tick-borne) transmission routes, with transstadial or with transovarial transmission by ticks appeared to be associated with the biotope type, with the tick species, or both, respectively.     

Detection of Alpha and Gamma-Proteobacteria in <Emphasis Type="Italic">Amblyomma triste</Emphasis> (Acari: Ixodidae) from Uruguay

Amblyomma triste is the most prevalent tick species reported in human tick bites in Uruguay and has been found to be infected with Rickettsia parkeri, but no other microorganisms have been reported from this tick. A sample of 254 adults of A. triste was collected by flagging on vegetation in suburban areas in southern Uruguay. Pools of five ticks were assembled and a screening for the DNA from the resulting 51 pools was realized by PCR assays using primers for amplifying a fragment of 16S rRNA gene for members of Anaplasmataceae. Seventeen pools were positive (33%) and the sequenciation of the gene fragment amplified revealed the presence of a putative new Alpha-Proteobacterium (denominated Atri-uru). The phylogenetic analysis showed that this microorganism is closely related to the symbiont of I. ricinus denominated ‘Candidatus Midichloria mitochondrii’ and other associated organisms. This rickettsial symbiont of ticks is included in a recent new clade proposed for the Alpha subclass of the Proteobacteria. The discovery of this bacterium in A. triste is the first evidence of this group of Rickettsiales detected in the Genus Amblyomma, and the first record in South America. Also, in two of 17 positive samples a Gamma-Proteobacterium related to Francisella-like organisms was detected.     

Prevalence of Anaplasma and Bartonella spp. in Ticks Collected from Korean Water Deer (Hydropotes inermis argyropus)

Deer serve as reservoirs of tick-borne pathogens that impact on medical and veterinary health worldwide. In the Republic of Korea, the population of Korean water deer (KWD, Hydropotes inermis argyropus) has greatly increased from 1982 to 2011, in part, as a result of reforestation programs established following the Korean War when much of the land was barren of trees. Eighty seven Haemaphysalis flava, 228 Haemaphysalis longicornis, 8 Ixodes nipponensis, and 40 Ixodes persulcatus (21 larvae, 114 nymphs, and 228 adults) were collected from 27 out of 70 KWD. A total of 89/363 ticks (266 pools, 24.5% minimum infection rate) and 5 (1.4%) fed ticks were positive for Anaplasma phagocytophilum using nested PCR targeting the 16S rRNA and groEL genes, respectively. The 16S rRNA gene fragment sequences of 88/89 (98.9%) of positive samples for A. phagocytophilum corresponded to previously described gene sequences from KWD spleen tissues. The 16S rRNA gene fragment sequences of 20/363 (5.5%) of the ticks were positive for A. bovis and were identical to previously reported sequences. Using the ITS specific nested PCR, 11/363 (3.0%) of the ticks were positive for Bartonella spp. This is the first report of Anaplasma and Bartonella spp. detected in ticks collected from KWD, suggesting that ticks are vectors of Anaplasma and Bartonella spp. between reservoir hosts in natural surroundings.     

Tick-Borne Rickettsial Pathogens in Ticks and Small Mammals in Korea

In order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (Hemaphysalis spp. and Ixodes spp.) were screened using molecular techniques. Ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the Republic of Korea (ROK) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). From the 1,638 tick samples, species-specific fragments of Anaplasma phagocytophilum (1 sample), Anaplasma platys (52 samples), Ehrlichia chaffeensis (29 samples), Ehrlichia ewingii (2 samples), Ehrlichia canis (18 samples), and Rickettsia rickettsii (28 samples) were amplified by PCR assay. Twenty-one pooled and individual tick samples had mixed infections of two (15 samples) or three (6 samples) pathogens. In addition, 424 spleen samples from small captured mammals (389 rodents, 33 insectivores, and 2 weasels) were screened for selected zoonotic pathogens. Species-specific DNA fragments of A. phagocytophilum (110 samples), A. platys (68 samples), E. chaffeensis (8 samples), E. ewingii (26 samples), E. canis (51 samples), and Rickettsia sp. (22 samples) were amplified by PCR assay. One hundred thirty small mammals had single infections, while 4, 14, and 21 striped field mice (Apodemus agrarius) had mixed infections of four, three, and two pathogens, respectively. Phylogenetic analysis based on nucleotide sequence comparison also revealed that Korean strains of E. chaffeensis clustered closely with those from China and the United States, while the Rickettsia (rOmpA) sequences clustered within a clade together with a Chinese strain. These results suggest that these agents should be considered in differential diagnosis while examining cases of acute febrile illnesses in humans as well as animals in the ROK.     

First survey of ticks,tick-borne pathogens (Theileria,Babesia, Anaplasma and Ehrlichia) and Trypanosoma evansi in protected areas for threatened wild ruminants in Tunisia

The aim of the study was to identify ticks present in the environment and wild Tunisian ruminants and to detect tick-borne pathogens and Trypanosoma evansi DNA in these specimens. Sampling was done throughout each season from the environment in three protected areas around Tunisia: El Feidja, Haddaj and Oued Dekouk. Ticks were collected also, from one fawn of Barbary red deer and eight naturally deceased wild ruminants (one Barbary red deer, five Scimitar-horned oryx, one Addax antelope and one Dorcas gazelle), all of which lived in various protected areas. PCR and nested PCRs were performed to detect the presence of Theileria spp., Babesia spp., Trypanosoma evansi, Ehrlichia spp., Anaplasma spp., Anaplasma bovis and Anaplasma phagocytophilum DNA in these tick specimens. A total of 352 ticks were collected, belonging to six different species: Hyalomma excavatum (80.6%), Hyalomma dromedarii (10.2%), Hyalomma marginatum (0.5%), Rhipicephalus bursa (0.5%), Rhipicephalus sanguineus sensu lato (5.1%) and Ixodes ricinus (2.8%). Pathogens have been detected in 25% of H. dromedarii, 9.1% of H. excavatum and 5% of R. sanguineus sensu lato. The percentage of detection of T. evansi was 0.2%. Ehrlichia spp.-Anaplasma spp. were detected in 10.1% of ticks. Anaplasma spp. and A. bovis were detected in 7.6%, and 0.8% of examined ticks, respectively. None of the Theileria spp., Babesia spp., or A. phagocytophilum DNA was detected in the tested ticks. To our knowledge, the present study represents the first identification of these six tick species and the first detection of rickettsial pathogens and T. evansi in North African wild ruminants' species. These results extend the knowledge about the diversity of ticks and tick-borne pathogens in wildlife and justify further investigations of the possible role of R. sanguineus sensu lato in the transmission of T. evansi.     

Avian Migrants Facilitate Invasions of Neotropical Ticks and Tick-Borne Pathogens into the United States

Migratory birds have the potential to transport exotic vectors and pathogens of human and animal health importance across vast distances. We systematically examined birds that recently migrated to the United States from the Neotropics for ticks. We screened both ticks and birds for tick-borne pathogens, including Rickettsia species and Borrelia burgdorferi. Over two spring seasons (2013 and 2014), 3.56% of birds (n = 3,844) representing 42.35% of the species examined (n = 85) were infested by ticks. Ground-foraging birds with reduced fuel stores were most commonly infested. Eight tick species were identified, including seven in the genus Amblyomma, of which only Amblyomma maculatum/Amblyomma triste is known to be established in the United States. Most ticks on birds (67%) were neotropical species with ranges in Central and South America. Additionally, a single Ixodes genus tick was detected. A total of 29% of the ticks (n = 137) and no avian blood samples (n = 100) were positive for infection with Rickettsia species, including Rickettsia parkeri, an emerging cause of spotted fever in humans in the southern United States, a species in the group of Rickettsia monacensis, and uncharacterized species and endosymbionts of unknown pathogenicity. No avian tick or blood samples tested positive for B. burgdorferi, the etiologic agent of Lyme disease. An extrapolation of our findings suggests that anywhere from 4 to 39 million exotic neotropical ticks are transported to the United States annually on migratory songbirds, with uncertain consequences for human and animal health if the current barriers to their establishment and spread are overcome.