Genus Ornithodoros Research Articles

Risk of African Swine Fever Virus Sylvatic Establishment and Spillover to Domestic Swine in the United States.

African swine fever virus (ASFV) causes a high-consequence foreign animal disease that has emerged along international trade routes. Owing to high lethality and resulting trade sanctions, establishment of this disease in the United States would have devastating economic consequences. ASFV can be transmitted by soft ticks in the genus Ornithodoros or directly between swine, including domestic, feral, and wild swine. Consequently, the spatial risk of ASFV establishment depends on where susceptible animals, with or without competent vectors, co-occur. We synthesized county-level historical records of soft tick occurrence, current maps of feral swine distribution, and domestic swine inventory to evaluate the risk of ASFV establishment and spillover in the United States. Areas of California, Florida, and much of the southwestern United States were classified as high risk for ASFV establishment and spillover should an introduction event occur. Our analyses indicate that California, Texas, Georgia, and Florida are high-priority candidates for proactive risk reduction strategies. Domestic swine are often produced in high-biosecurity environments, mitigating health risks associated with contacting infected hosts and vectors. However, small-scale and organic pig producers in much of the southern United States remain more vulnerable to disease emergence.

Occurrence of autogeny in a population of Ornithodoros fonsecai (Acari: Argasidae)

Ornithodoros fonsecai is an argasid tick that is endemic to Brazil and has been described in the municipality of Bonito, state of Mato Grosso do Sul. Some specimens of this species were found in a cave in the municipality of Nobres, state of Mato Grosso. The specific identification of this population was confirmed by means of morphology and molecular biology. The mitochondrial 16S rDNA partial sequence of this species from Nobres has been deposited in GenBank (MK158949). The objective of this study was to elucidate the biology of O. fonsecai from Nobres, and to report autogeny in this tick population. Along three laboratory generations was observed molting of first nymphal instar to the second instar without feeding, a typical behavior of species included in the subgenus Alectorobius. The first generation (F1) presented five nymphal instars (N1 to N5), and most of adults emerged through molting of N5. The last nymphal instar of second generation (F2) was N4, but most of adults emerged from N3. In the third generation (F3) the last nymphal instar was N5, with most of the adults emerging from N4. In F2, some females (n = 20) originated from N3 began laying eggs without a blood meal. It was observed that those N3 fed twice before they molted to autogenic females. However, autogenic behavior occurred in relation to third generation females (F3) with specimens originating from N4 (n = 12) that were fed only once as nymphs. This behavior has already been reported as obligatory for the genera Otobius and Antricola, while it is facultative for one species of genus Argas and for four species of genus Ornithodoros. However, the present report provides the first record of facultative autogeny for a species of Ornithodoros in Brazil.

Survey of Tick-borne-disease from Ornithodoros spp. in Uninhabited Islands of Korea.

ObjectiveThe aim of this study is to survey data of ticks distribution of Korean islands and to investigate pathogens in Argasid ticks.IntroductionTicks and tick-borne diseases have been thought global important issues, because it's affect to animal and human health and are the cause of significant economic losses. The genus Ornithodoros spp., which is included in Family Argasidae, is usually associated with wild animals including seabirds and it was difficult to investigate because seabirds’ nests are found in inaccessible uninhabited islands. However, Ornithodoros spp. has been known for the vector of many diseases including African swine fever.MethodsIn this study, nest with soil and litter of seabirds were collected, to investigate Ornithodoros species from 9 uninhabited islands, Nan-do, Chilsan-do, Chilbal-do, Sogukhol-do, Googul-do, Gaerin-do, Sasu-do, Hong-do (Hallyeohaesang) and Dok-do located western and southern part of the Korea from July, 2017 to September in 2018. The islands are known for breeding places of migratory and resident birds. Maximum ten nests with soil and litter of seabirds were collected from one uninhabited island for the conservation of the islands environment. Ticks were collected from nest with soil and litter of seabirds using Tullgren funnel and were assayed for tick identification by PCR using 16S rRNA gene and tick-borne pathogens including Rickettia spp., Borrelia spp., Bartonella spp., Ehrlichia chaffensis, Ehrlichia canis, Anaplasma phagocytophilum and Anaplasma bovis by nested PCR.ResultsTotal 65 Ornithodoros species ticks from 338 seabird's (black-tailed gull, Larus crassirotris; streaked shearwater, Calonectris leucomelas and Swinhoe's storm petrel, Oceanodroma monorhis) nesting soil with litter in 9 uninhabited islands. In the sequence identification of 16S rRNA gene fragment of Ornithodoros species, O. capensis and O. sawaii were 37 and 28, respectively. In the analyses of tick-borne pathogens, Borrelia spp. (n=5) was detected in O. sawaii from Gaerin-do and Googul-do. The total detection rate of Borrelia sp. from Ornithodoros spp. was 7.69% (5/65).ConclusionsIn this research, we discovered that O. sawaii are habitat in west and southern part of uninhabited islands to breeding place of black-tailed gulls and streaked shearwater and O. capensis are habitat in uninhabited islands related to breeding place of streaked shearwater. This is first report of the Borrelia spp. from Ornithodoros sawaii in Korea.

Description of Ornithodoros montensis n. sp. (Acari, Ixodida: Argasidae), a parasite of the toad Rhinella arenarum (Amphibia, Anura: Bufonidae) in the Monte Desert of Argentina.

A new tick species of the genus Ornithodoros (Acari: Argasidae) was described from larvae collected on the toad Rhinella arenarum in a locality from Argentina belonging to the Monte Biogeographic Province. Ornithodoros montensis n. sp. was described based on morphological traits and sequences of the mitochondrial 16S rRNA gene. The diagnostic characters for this species are a combination of idiosoma oval, dorsal plate pyriform with posterior margin slightly concave, dorsal surface with 17 pairs of setae (7 anterolateral, 4 to 5 central and 5 to 6 posterolateral), ventral surface with 6 pairs of setae and 1 pair on anal valves, three pairs of sternal setae, postcoxal setae absent, and hypostome pointed apically with dental formula3/3 in the anterior half and 2/2 posteriorly almost to base. Phylogenetic analysis of 16S rDNA sequences and a principal component analysis based on morphometric characters provided additional support to the description of O. montensis as an independent lineage within the genus Ornithodoros. Larvae of O. montensis are phylogenetically closely related to O. puertoricensis, O. rioplatensis, O. talaje s.s., O. guaporensis, O. hasei and O. atacamensis, all of them belonging to the "O. talaje group".

ICTV Virus Taxonomy Profile: Asfarviridae.

The family Asfarviridae includes the single species African swine fever virus, isolates of which have linear dsDNA genomes of 170-194 kbp. Virions have an internal core, an internal lipid membrane, an icosahedral capsid and an outer lipid envelope. Infection of domestic pigs and wild boar results in an acute haemorrhagic fever with transmission by contact or ingestion, or by ticks of the genus Ornithodoros. Indigenous pigs act as reservoirs in Africa, where infection is endemic, and from where introductions occur periodically to Europe. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Asfarviridae, which is available at www.ictv.global/report/asfarviridae.

Fiebre recurrente transmitida por garrapatas: ¿otra etiología subdiagnosticada en Latinoamérica tropical?

La fiebre recurrente transmitida por garrapatas (FRTG) es una enfermedad infecciosa de carácter zoonótico causada por espiroquetas del género Borrelia, transmitidas al hombre y animales a través de la picadura de garrapatas “blandas” (familia Argasidae) del género Ornithodoros (1,2). En la naturaleza, las borrelias se mantienen en un ciclo enzoótico que involucra mamíferos silvestres (principalmente roedores), donde las garrapatas adquieren las espiroquetas después de cortos periodos de hematofagia (15-90 minutos), permaneciendo infectadas crónicamente con la posibilidad de transmitir los microorganismos a nuevos individuos vertebrados, incluyendo al hombre, quien actúa como un hospedero accidental (2).

African Swine Fever (ASF) and Ticks. No Risk of Tick-mediated ASF Spread in Poland and Baltic States.

Infectious diseases of swine, particularly zoonoses, have had a significant influence on nutritional safety and availability of pig meat as high-energy protein product since the time that pigs were domesticated back in the 7th century BC. The main sources of swine infectious diseases include the so-called primary sources (direct infection, i.e. through contact with infected and sick animals) and secondary sources (contaminated meat products, slaughter products, and vectors, including ticks). At present, the most serious epidemiological and economic threat to swine breeding in Europe is African swine fever (ASF). This disease, originally coming from Africa, is incurable and causes death of infected pigs and wild boars during 7−10 days after infection. Among the various factors that influence the spread of ASF, important role is played by ticks from the genus Ornithodoros, mainly from the species Ornithodoros moubata. Research on the ASF indicates that other species of ticks can also transmit the virus to healthy pigs in laboratory conditions. Sylvatic and domestic cycles of ASF virus transmission, which have been described so far, require further studies and updating in order to point the potential new vectors in the Caucasus and Eastern Europe affected by the ASF. Effective methods of control and biosecurity may significantly slow down the spread of ASF, which undoubtedly is a major threat to world pig production and international swine trade.

A 13-year old girl with pancytopenia at the presentation of a Borrelia hispanica infection: a case report and review of the literature

BackgroundIt is not uncommon that a child with a febrile illness of unknown etiology is admitted to the hospital. When the complete blood count reveals a pancytopenia, the diagnostic process can be a real challenge.Case presentationA 13-year girl of Arab-Berber descent presented with abdominal pain and fever after a holiday in northwestern Morocco. A complete blood count revealed a pancytopenia and blood smear test results revealed spirochetes. Borrelia hispanica was identified by sequencing the 16S ribosomal ribonucleic acid gene. Our patient was treated with tetracyclines and during this treatment we saw full clinical and hematological recovery.ConclusionsBorrelia hispanica is a known cause of tick-borne relapsing fever and is transmitted to humans through the bite of soft ticks of the genus Ornithodoros (Alectorobius). Although the link between tick-borne relapsing fever and thrombocytopenia has been documented, there are only a few case reports of tick-borne relapsing fever presenting with pancytopenia. To the best of our knowledge, there is no previous report of Borrelia hispanica presenting with pancytopenia.

Tick-borne relapsing fever in Sabzevar (Khorasan Razavy Province), North-Eastern Iran

Background: Soft ticks play an important role in transmission of bacteria, rikettsia and viral diseases to human. In Iran soft ticks of the genus Ornithodoros spread the tick-borne diseases.Objective: Present study was performed to investigate the latest situation of tick-borne relapsing fever (TBRF) among people and tick infectivity to Borrelia in Sabzevar, an endemic tick-borne relapsing fever region in Iran.Methodology: Ticks were collected in the sampled areas of Sabzevar County by clustered random sampling. The suspected cases of TBRF were passively detected in the study villages. Each of Ornitodoros tholozani was separately crushed and resultant homogenate was inoculated intraperitoneally into a white mouse.Results: A total of 3892 soft ticks were collected and identified. The Argas and Ornitodoros genus were observed 69.6 % and 30.4 %, respectively. Argas persicus, Ornitodoros lahorensis, O. tholozani and A. reflexus species were found 68.0 %, 25.6 %, 4.8% and 1.6 %, respectively. A. persicus (68.0 %) and A. reflexus were found as the highest and the lowest frequent species. Totally 5.2 % of O. tholozani ticks infected with Borrelia persica. Among individuals who suspected to the TBRF, 5 cases infected with B. persica.Conclusions: The vector infectivity rates were 5.2 % which can be an important factor and ability to make proper decide decision for better TBRF management and revision of control measures. Also this study raises our country TBRF epidemiological aspects and improves them.Bangladesh Journal of Medical Science Vol.15(4) 2016 p.551-555

African swine fever virus transmission cycles in Central Europe: Evaluation of wild boar-soft tick contacts through detection of antibodies against Ornithodoros erraticus saliva antigen.

BackgroundAfrican swine fever (ASF) is one of the most complex viral diseases affecting both domestic and wild pigs. It is caused by ASF virus (ASFV), the only DNA virus which can be efficiently transmitted by an arthropod vector, soft ticks of the genus Ornithodoros. These ticks can be part of ASFV-transmission cycles, and in Europe, O. erraticus was shown to be responsible for long-term maintenance of ASFV in Spain and Portugal. In 2014, the disease has been reintroduced into the European Union, affecting domestic pigs and, importantly, also the Eurasian wild boar population. In a first attempt to assess the risk of a tick-wild boar transmission cycle in Central Europe that would further complicate eradication of the disease, over 700 pre-existing serum samples from wild boar hunted in four representative German Federal States were investigated for the presence of antibodies directed against salivary antigen of Ornithodoros erraticus ticks using an indirect ELISA format.ResultsOut of these samples, 16 reacted with moderate to high optical densities that could be indicative of tick bites in sampled wild boar. However, these samples did not show a spatial clustering (they were collected from distant geographical regions) and were of bad quality (hemolysis/impurities). Furthermore, all positive samples came from areas with suboptimal climate for soft ticks. For this reason, false positive reactions are likely.ConclusionIn conclusion, the study did not provide stringent evidence for soft tick-wild boar contact in the investigated German Federal States and thus, a relevant involvement in the epidemiology of ASF in German wild boar is unlikely. This fact would facilitate the eradication of ASF in the area, although other complex relations (wild boar biology and interactions with domestic pigs) need to be considered.

A 13-Year Old Female with Pancytopenia at the Presentation of a Borrelia Hispanica Infection: Case Report and Review of the Literature

Background: It is not uncommon that a child with a febrile illness of unknown etiology is admitted to the hospital. When the complete blood count reveals a pancytopenia, the diagnostic process can be a real challenge. Case presentation: A 13-year female of Arab-Berber descent presented with abdominal pain and fever after a vacation in north-western Morocco. Complete blood count revealed a pancytopenia and blood smear revealed spirochetes. Borrelia hispanica was identified by sequencing the 16S rRNA gene. The patient was treated with tetracyclines and during this treatment we saw full clinical and hematological recovery. Conclusions: Borrelia hispanica is a known cause of Tick-borne relapsing fever and is transmitted to humans through the bite of soft ticks of the genus Ornithodoros (Alectorobius). Although the link between tick-borne relapsing fever (TBRF) and thrombocytopenia has been documented, there are only a few case reports of TBRF presenting with pancytopenia. To the best of our knowledge, there is no previously report of Borrelia hispanica presenting with pancytopenia.

New insights into the role of ticks in African swine fever epidemiology.

African swine fever (ASF), one of the most important diseases of swine, is present in many African countries, as well as in eastern Europe, Russia and Sardinia. It is caused by a complex virus, ASF virus (ASFV), for which neither vaccine nor treatment is available. ASFV affects swine of all breeds and ages, and also replicates in soft ticks of the genus Ornithodoros, facilitating ASFV persistence and reocurrence of disease. Depending on the involvement of these ticks, and the presence or not of sylvatic asymptomatic animals, several epidemiological cycles have been identified. The disease persists in East and southern African countries in a sylvatic cycle between O. porcinus (of the O. moubata species complex) and common warthogs. In some countries a domestic pig-tick cycle exists, whereas in other regions, notably West Africa, the role of soft ticks has not been demonstrated, and ASFV is transmitted between domestic pigs in the absence of tick vectors. Even in several East and Central African countries which have the sylvatic or domestic cycle, the majority of outbreaks are not associated with ticks or wild suids. In Europe, O. erraticus was detected and identified as a crucial vector for ASF maintenance in outdoor pig production on the Iberian Peninsula. However, in most parts of Europe, there is a lack of information about the distribution and role of Ornithodoros ticks in ASF persistence, particularly in eastern regions. This article reviews ASF epidemiology and its main characteristics, with a special focus on the distribution and role of soft ticks in ASF persistence in different settings. Information abouttick detection, control measures and future directions for research is also included.

New records of rare Ornithodoros (Acari: Argasidae) species in caves of the Brazilian Amazon

The genus Ornithodoros is worldwide distributed and features 113 known species. However, some species are rare and collections are scarce. The present paper expands the known distribution of two species of soft ticks, O. rondoniensis and O. marinkellei , by about 1400 km to the east, in caves in two municipal districts in the state of Para, northern Brazil. These species were previously known only from the western Brazilian Amazon. Furthermore, some morphological details and molecular analysis are shown.

Ornithodoros faccinii n. sp. (Acari: Ixodida: Argasidae) parasitizing the frog Thoropa miliaris (Amphibia: Anura: Cycloramphidae) in Brazil

BackgroundMost argasid ticks from the Neotropical region are parasites of mammals and birds, with a few records from reptiles. Many species of the genus Ornithodoros are known only through larval descriptions, and their chaetotaxy and morphological characteristics have been used to separate the taxa. In the present study, we describe the larva and the nymph of first instar of a new species of the genus Ornithodoros that was collected from frogs of the species Thoropa miliaris.MethodsLarvae of Ornithodoros were collected from frogs of the species T. miliaris at waterfalls in the state of Rio de Janeiro, southeastern Brazil. The larval and nymphal description was based on optical and scanning electron microscopy. Molecular analysis using the argasid 16S rRNA sequences available in GenBank was also conducted.ResultsOrnithodoros faccinii sp. n. is closely related to Ornithodoros clarki Jones & Clifford, Ornithodoros marinkellei Kohls, Clifford & Jones, Ornithodoros capensis Neumann and Ornithodoros sawaii Kitaoka & Susuki. However, the larval morphology of the new species is unique. The mitochondrial 16S rDNA partial sequence of O. faccinii generated in the present study was deposited in GenBank under the number KP861242.ConclusionsThe larvae collected from Thoropa miliaris are a new species, Ornithodoros faccinii n. sp. This is the first report of argasid ticks on frogs in Brazil, the second on frogs and the third on Amphibia in the Neotropical region.

Development of vaccines against Ornithodoros soft ticks: An update

Ticks are parasites of great medical and veterinary importance since they are vectors of numerous pathogens that affect humans, livestock and pets. Among the argasids, several species of the genus Ornithodoros transmit serious diseases such as tick-borne human relapsing fever (TBRF) and African Swine Fever (ASF). In particular, Ornithodoros erraticus is the main vector of these two diseases in the Mediterranean while O. moubata is the main vector in Africa. The presence of these Ornithodoros ticks in domestic and peridomestic environments may greatly hinder the eradication of TBRF and ASF from endemic areas. In addition, there is a constant threat of reintroduction and spreading of ASF into countries from where it has been eradicated (Spain and Portugal) or where it was never present (the Caucasus, Russia and Eastern Europe). In these countries, the presence of Ornithodoros vectors could have a tremendous impact on ASF transmission and long-term maintenance. Therefore, elimination of these ticks from at least synanthropic environments would contribute heavily to the prevention and control of the diseases they transmit. Tick control is a difficult task and although several methods for such control have been used, none of them has been fully effective against all ticks and the problems they cause. Nevertheless, immunological control using anti-tick vaccines offers an attractive alternative to the traditional use of acaricides. The aim of the present paper is to offer a brief overview of the current status in control measure development for Ornithodoros soft ticks, paying special attention to the development of vaccines against O. erraticus and O. moubata. Thus, our contribution includes an analysis of the chief attributes that the ideal antigens for an anti-tick vaccine should have, an exhaustive compilation and analysis of the scant anti-soft tick vaccine trials carried out to date using both concealed and salivary antigens and, finally, a brief description of the new reverse vaccinology approaches currently used to identify new and more effective protective tick antigens.

On the situation of African swine fever and the biological characterization of recent virus isolates

African swine fever (ASF), a disease notifiable to the World Organization of Animal Health (OIE), is characterized by severe, unspecific clinical signs and high mortality rates. Hosts for ASF virus (ASFV) are only members of the family Suidae and soft ticks of the genus Ornithodoros. Currently, no vaccine is available and therefore, the control is primarily based on strict sanitary measures. The most important part is the early detection of the disease within affected animal holdings and the fast and reliable confirmation by laboratory diagnosis. Infections of domestic pigs and European wild boar with recent Armenian, Sardinian, Lithuanian or Kenyan ASFV isolates lead to severe, acute disease courses with the predominant symptom of high fever (> 41 degrees C) accompanied by further unspecific clinical signs such as lethargy, loss of appetite, diarrhoea, respiratory symptoms, and an increased bleeding tendency. In experimental infection studies the mortality rate reached 100%. The most prominent pathomorphological findings included ebony-colored gastrohepatic lymph nodes, lung oedema, petechiae in the renal cortex, and oedema of the gallbladder wall. In the light of the current epidemiological situation with endemic ASFV infections on Sardinia, outbreaks in Russia and several Eastern EU Member States there is a risk for an introduction in further, previously unaffected EU countries including Germany. Hence, appropriate sample materials (serum, blood, spleen) of domestic pigs with unspecific clinical symptoms or pathomorphological findings should be examined for both ASFV and classical swine fever virus.

Two new species of Ornithodoros (Ixodida; Argasidae) from the Southern Cone of South America.

Two new species of the genus Ornithodoros were described from larvae collected in Argentina and Chile. Ornithodoros xerophylus n. sp. was described from specimens collected on the small rodent Graomys centralis in Argentina. The diagnostic characters for this species are a combination of dorsal plate slightly oval with a length of approximately 250 µm, 16 pairs of dorsal setae, hypostome with apex rounded and dental formula 2/2 in most rows, 3/3 apically, and capsule of the Haller's organ oval in shape without reticulations. Larvae of Ornithodoros lahillei n. sp. were collected on the reptiles Philodryas chamissonis and Callopistes maculatus in Chile. The diagnostic characters for O. lahillei are a combination of dorsal plate subtriangular with margins corrugated and posterior margin convex, dorsal surface with 14 pairs of setae, absence of postcoxal setae, and hypostome with apex pointed and dental formula 3/3 in anterior third and 2/2 in the middle and basal portion. Phylogenetic analysis of 16S rDNA sequences and a Principal Component Analysis based on morphometric characters provided additional support to the description of O. lahillei and O. xerophylus as two independent lineages within the genus Ornithodoros.

Borrelia crocidurae in Ornithodoros ticks from northwestern Morocco: a range extension in relation to climatic change?

Tick-borne relapsing fever (TBRF) is caused by Borrelia spirochetes transmitted to humans by Argasid soft ticks of the genus Ornithodoros. We investigated the presence of Ornithodoros ticks in rodent burrows in nine sites of the Gharb region of northwestern Morocco where we recently documented a high incidence of TBRF in humans. We assessed the Borrelia infection rate by nested PCR and sequencing. All sites investigated were colonized by ticks of the Ornithodoros marocanus complex and a high proportion of burrows (38.4%) were found to be infested. Borrelia infections were observed in 6.8% of the ticks tested. Two Borrelia species were identified by sequencing: B. hispanica and B. crocidurae. The discovery in northwestern Morocco of Ornithodoros ticks infected by B. crocidurae represents a 350 km range extension of this Sahelo-Saharan spirochete in North Africa. The spread of B. crocidurae may be related to the increasing aridity of northwestern Morocco in relation to climate change.

No evidence of African swine fever virus replication in hard ticks

African swine fever (ASF) is caused by African swine fever virus (ASFV), a tick-borne DNA virus. Soft ticks of the genus Ornithodoros are the only biological vectors of ASFV recognized so far. Although other hard ticks have been tested for vector competence, two commonly found tick species in Europe, Ixodes ricinus and Dermacentor reticulatus, have not been assessed for their vector competence for ASFV. In this study, we aimed to determine whether virus replication can occur in any of these two hard tick species (I. ricinus and/or D. reticulatus), in comparison with O. moubata (the confirmed vector), after feeding them blood containing different ASFV isolates using an improved in vitro system. DNA quantities of ASFV in these infected hard ticks were measured systematically, for 6 weeks in I. ricinus, and up to 8 weeks in D. reticulatus, and the results were compared to those obtained from O. moubata. There was evidence of virus replication in the O. moubata ticks. However, there was no evidence of virus replication in I. ricinus or D. reticulatus, even though viral DNA could be detected for up to 8 weeks after feeding in some cases. This study presents the first results on the possible vector competence of European hard (ixodid) ticks for ASFV, in a validated in vitro feeding setup. In conclusion, given the lack of evidence for virus replication under in vitro conditions, D. reticulatus and I. ricinus are unlikely to be relevant biological vectors of ASFV.

Horizontal gene transfer of a vertebrate vasodilatory hormone into ticks

The horizontal gene transfer (HGT) of functional molecules is found in higher eukaryotes, but its influence on their evolution has not been fully evaluated. Here we describe the HGT of a vertebrate vasodilator, adrenomedullin (ADM), into ticks of the genus Ornithodoros and hypothesize its involvement in tick evolution. The salivary glands of Ornithodoros ticks contain ADM-like vasodilators, tick-adrenomedullin (TAM). ADM-like molecules, including TAM, are conserved in all vertebrates and Ornithodoros ticks but not in any other invertebrates, including Argas ticks, which share a common ancestor with Ornithodoros ticks. In addition, the close evolutionarily relationship between TAM and ADM is supported through genomic sequence and phylogenetic relatedness analyses. Ornithodoros ticks horizontally acquired vertebrate ADM and currently employ it to facilitate blood feeding. The acquisition of TAM might result in a beneficial change in feeding behaviour and influence the divergence of Ornithodoros ticks.