Ticks and control methods

Paratransgenic quantum vaccinology

Tick vaccines are an environmentally friendly intervention for the prevention and control of tick-borne diseases affecting humans and animals worldwide. From our perspective, the challenges in tick vaccinology have encouraged the implementation of new interventions. In this opinion article we propose paratransgenic quantum vaccinology as a new approach that integrates platform trends in biotechnology, such as omics datasets combined with big data analytics, machine learning, and paratransgenesis with a systems biology perspective. This innovative approach allows the identification of protective epitopes in tick- and/or pathogen-derived proteins for the design of chimeric vaccine candidate antigens which can be produced by commensal/symbiotic microorganisms eliciting a protective response in the host.

Molecular Detection of Ehrlichia ruminantium in Cattle From Different Agro-Ecological Zones of Cameroon: Implication for the Understanding of the Heartwater Epidemiology

Although Amblyomma variegatum and Ehrlichia ruminantium infections have been reported in cattle from some agro-ecological zones (AEZs) of Cameroon, the transmission patterns of this bacterium seem to vary according to endemic areas and its prevalence as well as that of Heartwater remains not well understood in most sub-Saharan African countries. This study was designed to detect E. ruminantium infections in cattle of four AEZs of Cameroon and to identify areas presenting enzootic stability and those with potentially high risk for Heartwater. Blood samples were collected from cattle in four AEZs of Cameroon. DNA was extracted from blood and semi-nested PCR targeting the 16S rRNA gene of E. ruminantium was used to search for this bacterium. From 569 cattle analysed, an E. ruminantium DNA fragment was detected in 197 of them, giving an overall prevalence of 34.6%. The highest prevalence of E. ruminantium of 48.0% was recorded in cattle from AEZ IV and the lowest (26.0%) in those from AEZ III. Among the AEZs, significant differences (X2 = 14.85, p = 0.002) were recorded in terms of the prevalence of E. ruminantium infections. Villages of the westerly areas are at higher risk for E. ruminantium infections. This study revealed a high prevalence and a wide distribution of E. ruminantium infections in AEZs of Cameroon. It enabled the identification of areas showing an enzootic stability for E. ruminantium transmission as well as those where the transmission of this bacterium is low and where livestock are at higher risk of developing Heartwater.

Molecular Epidemiology and Phylogeny of Theileria ovis and Theileria lestoquardi in Sheep and Goats from Southern Punjab, Pakistan

Background: Theileria spp. are responsible for ovine and caprine theileriosis, leading to significant morbidity and mortality in small ruminants. The present study aims to investigate Theileria spp. infections in small ruminants from Southern Punjab in Pakistan, and genetic characterize revealed Theileria spp. isolates. Methods: A total of 93 sheep and 107 goats were sampled between May and August 2022. Blood smears were examined microscopically, and PCR amplification targeting the 18S rRNA gene was performed to detect Theileria spp. Additionally, specific PCR assays targeting 18S rRNA and ms1 partial sequences were used to identify Theileria ovis and T. lestoquardi, respectively.  Results: The prevalence of Theileria spp. was significantly higher using PCR (13.5%) compared to microscopic screening (5%). Sheep showed a higher prevalence rate (19.4%) compared to goats (8.4%) (p = 0.024). Young sheep aged ≤ 1 year were more commonly infected with Theileria spp. (41%) compared to older sheep (p = 0.006). The prevalence of Theileria spp. was higher in sheep-only herds (37.3%) compared to goat-only herds (18%) or mixed-species herds (8.1%) (p = 0.015). The prevalence rates of T. ovis and T. lestoquardi were 9% and 2.5%, respectively, with four animals (2 goats and 2 sheep) showing co-infection. Phylogenetic analysis revealed that our T. ovis 18S rRNA sequence clustered with previously reported sequences from sheep in Turkey, China, Spain, and goats in Tanzania. The obtained T. lestoquardi ms1 partial sequence formed a distinct cluster from other T. lestoquardi isolates in Pakistan and neighboring countries.  Conclusion: Theileria spp. co-circulation in Pakistani small ruminants, particularly the presence of T. ovis and T. lestoquardi, highlights the need for attention from animal health decision-makers due to their financial and health impacts.

Nuttalliella namaqua Bedford, 1931, a sole extant species of the genus Nuttalliella - a scoping review

Nuttalliella namaqua Bedford, 1931 is the sole extant tick species that belongs to the genus and family Nuttalliella and Nuttalliellidae respectively. With the characteristics that are respectively distinctive to hard and soft ticks, it is regarded as the species closest to the ancestral lineage of ticks as well as the missing link between the Argasidae and Ixodidae families. In this review, literature search of the articles reporting on N. namaqua was done in Google Scholar and PubMed databases. After relevance and eligibility screening, 12 articles were deemed eligible and appraised. The results showed that N. namaqua was respectively distinct to limited regions of Africa such as Botswana, Namibia, Mozambique, South Africa and Tanzania. The review also indicated that N. namaqua was collected from murid rodents, African Savanna hare, scrub hare, elephant shrews, rock hyraxes, black backed jackal, lizards and off-host in locations that include under a stone, rock crevices, on a rock wall and respectively in the nests of an eagle and a lesser striped swallow. Irrespective of all the reports, natural hosts of the nymphs are still not clearly defined. Numerous phylogeny studies have reported Nuttalliellidae as the sister-lineage to Argasidae and Ixodidae tick families. Moreover, a recent report indicated that the similarities between Nuttalliellidae and the fossil families Deinocrotonidae and Legionaris award them to be merged into one family, preferably Nuttalliellidae Thus, further research on this family, will perhaps provide more knowledge about its unclear distribution, life cycle as well as the evolution of ticks in general.

Morpho-molecular investigation of ectoparasitic infestation of companion animals in Sylhet city, Bangladesh

Ticks (Ixodida) and Fleas (Siphonaptera) are considered among the most important arthropod of public health concern due to their ability to transmit vector-borne pathogens to humans. By sharing a common environment, vector-borne diseases constituted major setbacks to the development of a pet population in Bangladesh. This study aimed to determine companion animal-associated ticks and fleas based on morpho-molecular approaches. Between December 2021 and May 2022, 74 animals (62 cats and 12 dogs) were examined, of which 17 (27.4%) cats and 9 (75.0%) dogs had ectoparasitic infestations, with 35.1% overall prevalence. Morphometrical examination showed the ectoparasites in these animals were Ctenocephalides spp. (flea) and Riphicephalus spp. (tick). Genetic analysis using the mitochondrial markers i.e. Cytochrome c oxidase subunit 1 (cox1) revealed the presence of two flea species i.e., Ctenocephalides canis, Ctenocephalides felis, and one tick species Rhipicephalus sanguineus. Interviews of animal owners indicate that 35.14% of them had no concern about ectoparasitic infestation or ectoparasites-borne diseases. Our results indicated that fleas and ticks were the most common ectoparasites in companion animals of this area. The zoonotic nature of some ectoparasites can be regarded as a public health alert. The findings will assist epidemiologists and policymakers in offering customized guidance for upcoming monitoring and preventive tactics in this area.

Participatory and Conventional Investigation of Tick Infestation in Camels and Cattle of Somali Pastoral Areas, Eastern Ethiopia

Ticks are a common parasite that affect many animals by causing slowed growth, reduced milk output, and financial losses for industries that depend on animal hides and skins. From June to December 2017, participatory and conventional investigations on tick infestation in camels and cattle were conducted in Kebribayah and Afdem districts of Ethiopia's Somali Regional State. The aim of this study was to determine the prevalence and density of ticks in these animals and establish strategic control measures to enhance livestock productivity and livelihoods in pastoral areas. The current study found that the prevalence of tick infestation in Kebribayah and Afdem districts was 83.3% and 86.8%, respectively. Rhipicephalus pulchellus (48.9%) was identified as the most common tick species in camels and cattle, followed by Amblyomma gemma (26.3%), Hyalomma truncatum (11.6%), Amblyomma lepidum (6.7%), and Amblyomma variegatum (6.5%). Among the variables considered, age and body condition score were significant risk factors (p < 0.001). Tick density varied depending on the recorded months and seasons (p < 0.001), with the highest mean tick density occurring in November (32.69 ± 21.750) and during the wet season (28.56 ± 19.750). Livestock owners in Kebribayah and Afdem ranked topical acaricide application as the most effective tick control method, followed by ivermectin injections, with the traditional hand removal method being the least effective. These rankings were consistent across both districts, and there was moderate agreement among livestock keepers from both regions regarding the best method. Afdem livestock keepers had slightly weak agreement on high tick burden in spring (W = 0.475, p = 0.127), and Kebribayah livestock keepers showed slightly strong agreement in tick burden across seasons (W = 0.700, p = 0.038), with spring having a significantly higher burden than winter. Consequently, participatory appraisal indicated that ticks were important and prevalent ectoparasites in the study area. Finally, strategic tick control appropriate for specific management and production environments should be implemented biannually in wet seasons.

Epidemiology and molecular characterization of Theileria annulata in ticks collected from cattle in the central part of Tamil Nadu, India

Tick-borne diseases are the most common in cattle in the tropical and subtropical regions of India and lead to substantial economic losses to small and marginal farmers. This study aimed to identify the diverse species of ticks infesting cattle in the central part of Tamil Nadu, India, and to assess the prevalence of Theileria annulata infection in various species of ticks through PCR. Out of 123 cross-bred and 105 native breed cattle examined for tick infestation, 40 (18%) and 29 (12.7%) cattle were infested with Ixodid ticks, respectively. The most prevalent tick species identified was Rhipicephalus microplus (n=589), followed by Hyalomma anatolicum (n=532), Hyalomma marginatum (n=145), Haemaphysalis intermedia (n=79), and Rhipicephalus haemophysaloides (n=1) found in the study area. The prevalence and intensity of the tick infestation were found to be higher in cross-bred (71.04%) than native breed cattle (28.96%), and there was no significant difference between the studied breeds (chi-square value =24; df =20; p value =0.24) was observed. However, a significant difference in the H. anatolicum tick infestation was observed between the Cauvery Delta (14.30%) and the North-Western (20%) zones of Tamil Nadu (p<0.05). DNA fragments of 193 bp derived from 18S rRNA gene sequences of T. annulata were amplified using species-specific primers. Of these, 16 out of 37 (43.2%) and 10 out of 39 (29%) pooled samples of H. anatolicum and 4 out of 18 (22.2%) and 1 out of 5 (20%) pooled samples of H. marginatum were found positive for T. annulata from the Cauvery Delta and North-Western zones, respectively. R. microplus, H. intermedia, and R. haemaphysaloides from these regions were negative. These findings confirm that H. anatolicum (52.17%) is the predominant vector for T.annulata rather than H. marginatum (18.84%), and the PCR is a useful method of determining the infection rates in ticks collected from animals carrying low levels of T. annulata piroplasms.

A social-ecological systems approach to tick bite and tick-borne disease risk management: Exploring collective action in the Occitanie region in southern France

Ticks are amongst the most important zoonotic disease vectors affecting human and animal health worldwide. Tick-borne diseases (TBDs) are rapidly expanding geographically and in incidence, most notably in temperate regions of Europe where ticks are considered the principal zoonotic vector of Public Health relevance, as well as a major health and economic preoccupation in agriculture and equine industries. Tick-borne pathogen (TBP) transmission is contingent on complex, interlinked vector-pathogen-host dynamics, environmental and ecological conditions and human behavior. Tackling TBD therefore requires a better understanding of the interconnected social and ecological variables (i.e., the social-ecological system) that favor disease (re)-emergence. The One Health paradigm recognizes the interdependence of human, animal and environmental health and proposes an integrated approach to manage TBD. However, One Health interventions are limited by significant gaps in our understanding of the complex, systemic nature of TBD risk, in addition to a lack of effective, universally accepted and environmentally conscious tick control measures. Today individual prevention gestures are the most effective strategy to manage TBDs in humans and animals, making local communities important actors in TBD detection, prevention and management. Yet, how they engage and collaborate within a multi-actor TBD network has not yet been explored. Here, we argue that transdisciplinary collaborations that go beyond research, political and medical stakeholders, and extend to local community actors can aid in identifying relevant social-ecological risk indicators key for informing multi-level TBD detection, prevention and management measures. This article proposes a transdisciplinary social-ecological systems framework, based on participatory research approaches, to better understand the necessary conditions for local actor engagement to improve TBD risk. We conclude with perspectives for implementing this methodological framework in a case study in the south of France (Occitanie region), where multi-actor collaborations are mobilized to stimulate multi-actor collective action and identify relevant social-ecological indicators of TBD risk.

Epidemiological analysis of cattle ticks and tick-borne pathogens in Gadag district, Karnataka state in India

In the present study, epidemiological analysis on 839 ticks collected from 50 cattle in Gadag district, Karnataka state, tick identification and detection of tick-borne pathogens was conducted by PCR, sequencing, and phylogeny. The morphological identification revealed that Haemaphysalis spp. [48.6%], Rhipicephalus spp. [48.4%], and Hyalomma spp. [3.0%] tick genera in Gadag district. Further, a higher infestation of Haemaphysalis spp. [69.0%] and Rhipicephalus spp. [62.3%] in Shirahatti and Gadag taluk, respectively was observed. Based on the taluk-wise and tick genus-wise analysis, a higher number of ticks was present in the dewlap region of cattle body sites, except for Hyalomma spp., the majority of which was present in the neck. Tick genus prevalence was 45.1, 42.7%, and 12.2 for Haemaphysalis spp., Rhipicephalus spp., and Hyalomma spp., respectively. The mean tick per cattle was 11.6, 11.0, and 2.5 for Rhipicephalus spp., Haemaphysalis spp., and Hyalomma spp., respectively. The prevalence of Anaplasma marginale, Babesia spp., and Rickettsia rickettsii was 8.0, 6.4, and 6.4%, respectively in the tick DNA samples and was negative for Ehrlichia and Theileria spp. The sequencing of the cytochrome oxidase subunit 1 gene revealed the presence of Haemaphysalis bispinosa, Rhipicephalus decoloratus, and Rhipicephalus microplus tick species in the Gadag district. The phylogenetic analysis revealed the tick species have similarities and identity with the isolates from India and neighboring countries. Thus, the study provides knowledge on tick genus distribution and tick-borne pathogens in Gadag district, Karnataka which will help in developing the control and prevention strategies by the policymakers and for profitable dairy farming by farmers.

Molecular detection of Babesia and Theileria species/genotypes in sheep and ixodid ticks in Erzurum, Northeastern Turkey: First report of Babesia canis in sheep

Piroplasmosis is a tick-borne protozoan disease caused by Babesia and Theileria species in ruminants. This study sought to determine the presence and prevalence of the agents causing piroplasmosis among sheep in Erzurum province, Turkey. It also sought to identify the tick species infesting the sheep and investigate the possible role of the ticks in the transmission of piroplasmosis. A total of 1621 blood samples and 1696 ixodid ticks from infested sheep were collected. Each blood sample and 115 tick pools were subjected to PCR assay. A total of 307 blood samples were found to be positive for Babesia spp. and Theileria spp. according to molecular analysis. The sequence analysis was revealed the presence of B. ovis (0.4%), B. crassa (0.4%), B. canis (0.4%), T. ovis (69.3%), Theileria sp. (26.6%), and Theileria sp. OT3 (2.9%) in 244 samples. The collected ticks were identified as D. marginatus (62.5%), Hae. parva (36.2%), Hae. punctata (1.1%), Rh. turanicus (0.1%), and H. marginatum (0.1%). The molecular analysis of the adult tick samples revealed T. ovis and T. annulata positivity in the D. marginatus pools, B. crassa and T. ovis positivity in the Hae. parva pools, and T. ovis positivity in the Hae. punctata pools. These results provide up-to-date data concerning tick-borne protozoan diseases of sheep and tick species infesting sheep in the region. The sheep breeding industry is an important livelihood for the region so it is essential to perform repeated studies on these pathogens in order to prevent disruptions to animal husbandry.

Host-pathogen interaction in arthropod vectors: Lessons from viral infections

Haematophagous arthropods can harbor various pathogens including viruses, bacteria, protozoa, and nematodes. Insects possess an innate immune system comprising of both cellular and humoral components to fight against various infections. Haemocytes, the cellular components of haemolymph, are central to the insect immune system as their primary functions include phagocytosis, encapsulation, coagulation, detoxification, and storage and distribution of nutritive materials. Plasmatocytes and granulocytes are also involved in cellular defense responses. Blood-feeding arthropods, such as mosquitoes and ticks, can harbour a variety of viral pathogens that can cause infectious diseases in both human and animal hosts. Therefore, it is imperative to study the virus-vector-host relationships since arthropod vectors are important constituents of the ecosystem. Regardless of the complex immune response of these arthropod vectors, the viruses usually manage to survive and are transmitted to the eventual host. A multidisciplinary approach utilizing novel and strategic interventions is required to control ectoparasite infestations and block vector-borne transmission of viral pathogens to humans and animals. In this review, we discuss the arthropod immune response to viral infections with a primary focus on the innate immune responses of ticks and mosquitoes. We aim to summarize critically the vector immune system and their infection transmission strategies to mammalian hosts to foster debate that could help in developing new therapeutic strategies to protect human and animal hosts against arthropod-borne viral infections.

Natural levels of Rhipicephalus microplus infestation and Anaplasma marginale infection in Angus and Ultrablack calves

Infections by Anaplasma marginale and infestations by Rhipicephalus microplus occur endemically in Brazil, representing an obstacle to expanding the use of taurine breeds, which are more susceptible. In this study, the levels of infection by A. marginale and infestation by R. microplus were monitored in 31 calves that were either purebred or had a high degree of taurine blood: 17 Angus (100% taurine) and 14 Ultrablack (ca. 82% taurine and 18% Zebu). The animals were evaluated on 13 occasions at 12-day intervals. The levels of A. marginale infection were determined by quantification of DNA copy number (CN) by qPCR, and ticks were monitored by two methods: counting adult females (≥ 4.5 mm) and scoring the level of tick infestation considering all visible instars in the animals' bodies. No significant effects were observed between the means of CN of A. marginale, tick counts and scores among Angus and Ultrablack animals. The repeatability estimates for CN of A. marginale, tick counts and tick scores were 0.53, 0.12 and 0.16, respectively. The correlations between CN and tick counts and scores were close to zero, whereas the correlations between tick assessment methods were 0.57. The absence of differences between the two genetic groups indicates, under the conditions of the present study, that the low degree of Zebu blood did not influence the levels of infection by A. marginale or infestation by R. microplus. The results also suggest that the evaluation of the levels of infestation by ticks using scores can provide information closer to the real infestation rate considering that it uses all the visible instars of the parasites.

Descriptive DNA barcoding of Argas (Persicargas) arboreus and Argas (Persicargas) persicus ticks (Ixodida: Argasidae) infesting birds in Egypt

Argas ticks are primary parasites of birds with veterinary importance. Nevertheless, these ticks have received little attention regarding molecular identification studies. DNA barcoding is a powerful technique for identifying tick species besides traditional morphological identification. The present work is a first effort to divulge DNA sequences of Argas (Persicargas) arboreus from Egypt and worldwide. We used cytochrome c oxidase subunit I (COI) from A. arboreus infesting herons, and from the fowl tick Argas (Persicargas) persicus. Our results pointed out another success for the Folmer primers that are widely used in DNA barcoding, permitting the discrimination of morphologically similar A. arboreus and A. persicus.

The control of Hyalomma ticks, vectors of the Crimean–Congo hemorrhagic fever virus: Where are we now and where are we going?

At a time of major global, societal, and environmental changes, the shifting distribution of pathogen vectors represents a real danger in certain regions of the world as generating opportunities for emergency. For example, the recent arrival of the Hyalomma marginatum ticks in southern France and the concurrent appearance of cases of Crimean–Congo hemorrhagic fever (CCHF)—a disease vectored by this tick species—in neighboring Spain raises many concerns about the associated risks for the European continent. This context has created an urgent need for effective methods for control, surveillance, and risk assessment for ticks and tick-borne diseases with a particular concern regarding Hyalomma sp. Here, we then review the current body of knowledge on different methods of tick control—including chemical, biological, genetical, immunological, and ecological methods—and the latest developments in the field, with a focus on those that have been tested against ticks from the genus Hyalomma. In the absence of a fully and unique efficient approach, we demonstrated that integrated pest management combining several approaches adapted to the local context and species is currently the best strategy for tick control together with a rational use of acaricide. Continued efforts are needed to develop and implement new and innovative methods of tick control.

Disease-bearing Hyalomma ticks are an increasingly emerging threat to humans and livestock worldwide. Various chemical, biological, genetic, and ecological methods for tick control have been developed, with variable efficiencies. Today, the best tick control strategy involves an integrated pest management approach.

Molecular detection of pathogens in the ova and unfed larvae of Rhipicephalus annulatus and Haemaphysalis bispinosa ticks infesting domestic cattle of south India

This study aimed to investigate the presence of pathogens in the engorged ticks infesting domestic cattle, their ova, and unfed larvae. The engorged female ticks infesting domestic cattle of Wayanad district of Kerala, south India were collected and kept for oviposition. The dead females after the complete oviposition, their egg masses, and unfed larvae were screened for the presence of various pathogens by specific PCRs. The presence of Babesia bigemina, Anaplasma marginale, A. phagocytophilum, and Rickettsia spp. similar to R. raoultii was confirmed in Rhipicephalus annulatus ticks, their egg masses, and unfed larvae. Theileria orientalis was detected in Rh. annulatus females, but not in their egg masses or progenies. The presence of A. phagocytophilum and Rickettsia spp. similar to R. raoultii was confirmed in Haemaphysalis bispinosa ticks, their egg masses, and unfed larvae too. The presence of coinfections of B. bigemina with A. phagocytophilum and A. marginale were detected in Rh. annulatus ticks and their progenies.

Geographical distribution of hard ticks (Acari:Ixodidae) and tick-host associations in Benin, Burkina-Faso, Ivory-Coast and Togo

Knowledge of ticks and associated pathogens is crucial to assess the risk of exposure of humans and animals to pathogens. For this review, we collected relevant data from published articles and field collections to provide an update on the biodiversity of ticks, and tick-host associations in four countries of West Africa: Benin, Burkina-Faso, Ivory-Coast, and Togo. The literature review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search was limited to literature published from 1953 to 2021 in English and French sources. Out of 104 articles retrieved, only 41 studies met the eligibility criteria and were included in the review. The final database included a total of 53,619 adults, nymphs and larval ticks belonging to 24 species and five genera (Amblyomma, Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus) that were collected from 23 different species of wild and domestic animals. This is the first record of Ixodes aulacodi and Rhipicephalus simpsoni in Benin, together with two new host records for A. latum. This checklist allows an update on tick-host associations and provides information on the diversity of ticks in West Africa.

Seasonal Dynamics and Predilection Sites of Ticks (Acari: Ixodidae) Feeding on Cows in the Western Parts of the Djurdjura, Algeria

The present study aimed to determine the phenology and predilection sites of ticks infesting cattle in the western region of Djurdjura (North Algeria) from November 2018 and October 2020. Nineteen cattle farms located in thirteen localities within four provinces were visited monthly for two years. Among the 289 examined cattle, 64.36 ± 2.81% (n=189) were infested by ticks. Of the 10,243 collected ticks, the most abundant tick species was Rhipicephalus bursa (31.57 ± 0.46%), followed by R. annulatus (31.26 ± 0.45%), Hyalomma marginatum (10.67 ± 0.30%), H. lusitanicum (7.02 ± 0.25%), H. excavatum (5.52±%0.22), H. scupense (4.27 ± 0.19%) and H. impeltatum (3.32 ± 0.17%). Ticks of the Hyalomma species were present throughout the year but in a limited number during the winter. H. scupense and H. impletatum showed similar activity from March to October and peaked in April and July, respectively (P&lt;0.001). H. lusitanicum and H. excavatum were active from April to November and both peaked in September and October respectively. Rhipicephalus bursa was collected from April to August and R. annulatus from July to October. R. turanicus was active between April and June. Hyalomma genus had an affinity of attachment for the inguinal region (P&lt;0.001). All parasitic stages of R. annulatus had an affinity for the necks (P&lt;0.001). Nymphs of R. bursa prefer the neck (P&lt;0.001), the adults attach to the perennial and inguinal regions (P&lt;0.001). R. turanicus attach to the ears (P&lt;0.001). As far as we know, this is the first study on the phenology and predilection sites of cattle ticks in the west region of Djurdjura in Algeria.

Anti-Tick Vaccines: Current Advances and Future Prospects

Ticks are increasingly a global public health and veterinary concern. They transmit numerous pathogens that are of veterinary and public health importance. Acaricides, livestock breeding for tick resistance, tick handpicking, pasture spelling, and anti-tick vaccines (ATVs) are in use for the control of ticks and tick-borne diseases (TTBDs); acaricides and ATVs being the most and least used TTBD control methods respectively. The overuse and misuse of acaricides has inadvertently selected for tick strains that are resistant to acaricides. Furthermore, vaccines are rare and not commercially available in sub-Saharan Africa (SSA). It doesn't help that many of the other methods are labor-intensive and found impractical especially for larger farm operations. The success of TTBD control is therefore dependent on integrating all the currently available methods. Vaccines have been shown to be cheap and effective. However, their large-scale deployment for TTBD control in SSA is hindered by commercial unavailability of efficacious anti-tick vaccines against sub-Saharan African tick strains. Thanks to advances in genomics, transcriptomics, and proteomics technologies, many promising anti-tick vaccine antigens (ATVA) have been identified. However, few of them have been investigated for their potential as ATV candidates. Reverse vaccinology (RV) can be leveraged to accelerate ATV discovery. It is cheap and shortens the lead time from ATVA discovery to vaccine production. This chapter provides a brief overview of recent advances in ATV development, ATVs, ATV effector mechanisms, and anti-tick RV. Additionally, it provides a detailed outline of vaccine antigen selection and analysis using computational methods.

Distribution and prevalence of ticks and tick-borne pathogens of wild animals in South Africa: A systematic review

Ticks are significant ectoparasites of animals and humans. Published data indicate that most vectors that transmit livestock and human pathogens in sub-Saharan Africa, are native to the region and originate from wild animals. Currently, there is a paucity of information on the role of wild animals on the epidemiology of zoonotic tick-borne pathogens in South Africa. This systematic review focuses on the distribution of ticks and prevalence of tick-borne pathogens in different wild animals in South Africa to identify potential reservoir hosts and possible hotspots for emergence of novel tick-borne pathogens. Following several screening processes, 38 peer-reviewed studies published from 1970 to 2021, were deemed eligible. The studies reported on ticks collected from 63 host species of 21 host families, mostly Canidae, Felidae, Bovidae and Muridae. A total of 49 tick species of nine genera, i.e. Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, Margaropus, Nuttalliella, Rhipicentor and Rhipicephalus, were reported. Nine tick species, i.e. Amblyomma marmoreum, Am. hebraeum, Haemaphysalis elliptica, Hyalomma truncatum, I. rubicundus, Rh. appendiculatus, Rh. (B.) decoloratus, Rh. evertsi evertsi and Rh. simus were the most commonly reported. Pathogens of the genera Anaplasma, Babesia, Hepatozoon and Theileria were identified in the wild animals. This review provides more insight on the ecology of ticks and tick-borne pathogens of wild animals in South Africa and gives useful information for predicting their future spread. It also demonstrates that wild animals habour a diverse range of tick species. This level of diversity entails a similarly high potential for emergence of novel tick-borne pathogens. The review further indicates that wild animals in South Africa are sentinels of tick-borne protozoans of veterinary importance and some bacterial pathogens as most ticks they habour are known vectors of pathogens of domestic animals and humans. However, studies on potential tick-borne zoonoses are under-represented and should be included in future epidemiological surveys, especially in the light of climate change and other anthropogenic threats which might result in the emergence of novel tick-borne pathogens.

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Wild animals in South Africa harbor a wide range of tick species of veterinary and medical importance.

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Forty-nine tick species belonging to 9 genera were reported from 63 wild host species of 21 families.

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Majority of the ticks occur throughout all nine provinces of South Africa.

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Wildlife in South Africa are sentinels of tick-borne protozoans and some bacterial pathogens of veterinary importance.

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The review also emphasizes the host preference of the ticks and the pathogens they transmit.

Cattle ticks and tick-borne diseases: a review of Uganda's situation

Herein we review the epidemiology of ticks and tick-borne diseases (TTBDs), their impact on livestock health and on the economy, control and associated challenges in Uganda. Ticks are leading vectors of economically important pathogens and are widespread in Uganda due to suitable climatic conditions. Besides the physical injury inflicted on the animal host, ticks transmit a number of pathogens that can cause morbidity and mortality of livestock if untreated, resulting in economic losses. Uganda suffers an aggregated annual loss (direct and indirect) of over USD 1.1 billion in the TTBDs complex. East Coast fever (ECF) caused by a protozoan haemoparasite, Theileria parva, is the most prevalent and economically important tick-borne disease (TBD) in Uganda and its vector, the brown ear tick (Rhipicephalus appendiculatus) widely distributed. Other prevalent TBDs in Uganda include anaplasmosis, babesiosis and heartwater. We highlight the role of agro-ecological zones (AEZs) and livestock management system in the distribution of TTBDs, citing warm and humid lowlands as being ideal habitats for ticks and endemic for TBDs. Control of TTBDs is a matter of great importance as far as animal health is concerned in Uganda. Indigenous cattle, which make up over 90% of the national herd are known to be more tolerant to TTBDs and most farms rely on endemic stability to TBDs for control. However, exotic cattle breeds are more capital intensive than indigenous breeds, but the increasing adoption of tick-susceptible exotic cattle breeds (especially dairy) in western and central Uganda demands intensive use of acaricides for tick control and prevention of TBDs. Such acaricide pressure has unfortunately led to selection of acaricide-resistant tick populations and the consequent acaricide resistance observed in the field. Vaccination against ECF, selective breeding for tick resistance and integrated tick control approaches that limit tick exposure, could be adopted to interrupt spread of acaricide resistance. We recommend increasing monitoring and surveillance for TTBDs and for emerging acaricide resistance, improved extension services and sensitization of farmers on tick control measures, appropriate acaricide use and the development and implementation of vaccines for the control of TTBDs as more sustainable and effective interventions. A tick control policy should be developed, taking into account variations of agro-ecological zones, farm circumstances and indigenous technical knowledge, and this should be incorporated into the overall animal health program.

The Efficacy of Ultrasonic Pest Repellent Devices against the Australian Paralysis Tick, Ixodes holocyclus (Acari: Ixodidae)

Ultrasonic pest repellers are often promoted as a means of protecting people and pets from the bites of hematophagous arthropods, such as ticks. However, to date, there has been no published research on the effectiveness of these devices against the Australian paralysis tick, Ixodes holocyclus Neumann. The purpose of this study was to test the effectiveness of nine ultrasonic devices against female I. holocyclus. Two arenas were constructed, one for the test (with the ultrasonic device) and one for the control (no device). Each arena had a test and an escape chamber, connected by a corridor. Twenty ticks were placed in each test chamber. After the ultrasonic device was operated for 1 h, the number of ticks in both chambers was recorded. Ten replicates were conducted for each device. The average number of ticks that moved from the test to the escape chamber was greater in all the test arenas, with three devices being statistically different from the control. However, the highest percent of ticks that escaped was only 19.5%. This amount is insufficient to offer adequate protection against tick bites and this study adds further weight to previous investigations that ultrasonic devices should not be employed in pest management.

Interactive effects of biological, human and environmental factors on tick loads in Boran cattle in tropical drylands

Background

Tick-borne diseases (TBDs) are a serious threat to humans, wildlife and livestock, and cause severe economic losses in many tropical drylands. The effective control of TBDs has been constrained by limited understanding of what determines tick loads in animals. We tested interactive effects of several biological factors (sex, age and body condition), one environmental factor (rainfall) and one human factor (management type) on tick loads in animals.

Methods

We collected ticks on animals at four sampling sites in the semi-arid savanna area of Laikipia County, Kenya, of which two are commercial ranches and the other two are open pastoral grazing areas. From 2017 to 2019, we collected a total of 2038 ticks from 619 domestic animals from various cattle and camel herds and from 79 tranquilised wild animals.

Results

Generally, wild herbivores (zebras, rhinos and elephants) had higher tick loads than domestic animals. As 83% of the tick samples were taken from Boran cattle, we analysed tick load in these cattle in more detail. Boran cattle had high tick loads in the wet season, especially those animals in poor condition. No differences were found between female and male cattle, regardless of season. The calves had high tick loads during both the wet and dry seasons, whereas the sub-adult and adult cattle had less ticks during the dry season. Cattle on the intensively managed ranches had lower tick load than those in the transhumant management system.

Conclusion

These findings highlight the importance of establishing effective control of ticks on domestic animals in transhumant management systems as tick loads were high on these animals in both the wet and dry season.

Graphic abstract

Ticks and Tick-Borne Diseases of Livestock in the Middle East and North Africa: A Review

Ticks are important vectors of an array of viral, bacterial and protozoan pathogens resulting in a wide range of animal and human diseases. There is limited information in the literature about tick species in the Middle East and North Africa (MENA) countries, even though they have suitable climate and vegetation for ticks and their hosts. We reviewed the occurrence of tick species and the pathogens they transmit from the MENA on published papers from 1901-2020. We found taxonomic records of 55 tick species infesting livestock representing the following eight genera: Ornithodoros, Otobius, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, and Rhipicephalus. In addition, 15 pathogens were recorded causing diseases of significance, with Crimean-Congo hemorrhagic fever, theileriosis, babesiosis and anaplasmosis being widely distributed diseases in the region. In recent decades, there has been increasing trends in disease occurrence and movement associated with global movement of humans and global trade of animals. We suggest that disease control and prevention could be achieved effectively through good integration between public health, veterinary medicine and animal management, and ecological approaches. We recommend further research in the areas of tick ecology and tick born-disease transmission. Furthermore, we suggest evaluation and improvement of disease control policies in the region.

First Molecular Detection of Babesia ovis, Theileria spp., Anaplasma spp., and Ehrlichia ruminantium in Goats from Western Uganda

Ticks and tick-borne diseases are major impediments to livestock production. To date, there have been several studies on the prevalence of tick-borne pathogens (TBPs) in cattle, but very few studies have documented TBPs in goats in Uganda. In this study, polymerase chain reaction assays and sequence analysis of different molecular markers were used to assess the presence and genetic characteristics of TBPs in 201 goats from Kasese district in western Uganda. The risk factors associated with TBP infections were also analyzed. We detected Theileria spp. (13.4%), Anaplasma phagocytophilum (10.9%), Anaplasma ovis (5.5%), Babesia ovis (5.5%), and Ehrlichia ruminantium (0.5%). The sequences of B. ovis ssu rRNA and A. ovismsp4 genes showed some degree of diversity among the parasite isolates in this study. The E. ruminantium pCS20 sequence formed a well-supported clade with isolates from Amblyomma variegatum ticks from Uganda. Wildlife interaction, sampling location, low body condition score, tick infestation, and herd size were significantly associated with TBP infections in the goats. The findings in this study provide important information on the epidemiology of tick-borne pathogens in Uganda, and show that goats could be potential reservoirs for tick-borne pathogens.

Detection and Molecular Characterization of Babesia canis vogeli and Theileria annulata in Free-Ranging Dogs and Ticks from Shahriar County, Tehran Province, Iran

Background:

We aimed to detect and characterize vector-borne parasites of Babesia and Theileria in dog and ticks by PCR assay. Canine babesiosis is a significant tick-borne disease caused by different Babesia species. As the infection has not been reported in Shahriar region Tehran, Iran, molecular techniques allowed us to identify tick-borne parasites in asymptomatic dogs.

Methods:

The number of 40 dog peripheral blood samples and 27 skin attached ticks were analyzed by molecular PCR assay. The specific primers were used for detecting Babesia canis, B. gibsoni and T. annulata.

Results:

B. c. vogeli was detected in 10 dog blood samples (25%). Additionally, T. annulata infection was identified in 13 dog blood samples (32.5%) and 18 isolated tick DNAs (66.7%). The results of PCR were confirmed by 18S rRNA and Tams1 gene sequence analyzing and have been registered in GenBank under following accession numbers for B. c. vogeli (MH793502) and T. annulata (MK105284). Conclusion: The verification of T. annulata infection in free-ranging dogs and ticks shows dogs might be considered as important natural carriers/reservoirs for T. annulata in enzootic region for bovine theileriosis. The obtained data may be useful for veterinary practitioners and dog owners to aware of Babesia and Theileria infection in dog and tick to establish the effective preventive measures.

Molecular Detection, Phylogenetic Analysis, and Genetic Diversity of Theileria annulata, Babesia bigemina, and Anaplasma marginale in Cattle in Three Districts of Egypt

BACKGROUND

Under the poor hygienic conditions, tick-borne pathogens cause severe economic losses to the cattle industry.

PURPOSE

The current study investigated the presence of Theileria annulata, Babesia bigemina, and Anaplasma marginale, the most relevant tick-borne pathogens in cattle, in 3 provinces of Egypt utilizing species-specific PCR assays.

METHODS

PCR was conducted, on bovine blood specimens, using primers targeting the T. annulata merozoite-piroplasm surface antigen (Tams1, 768 bp), A. marginale major surface protein-1b gene (msp1b, 265 bp), and B. bigemina small subunit ribosomal RNA gene (SSrRNA, 543 bp).

RESULTS

PCR findings revealed overall prevalences of T. annulata, B. bigemina, and A. marginale as 22.0% (33/150), 19.33% (29/150), and 10.6% (16/150), respectively. The co-infection with two or three pathogens was detected in 20.0% (30/150) of examined specimens. Sequence analyses indicated that T. annulata and A. marginale varied from those of corresponding GenBank sequences revealing percent identities ranging from 90.68 to 97.75% and from 94.98 to 98.63%, respectively. On the other hand, the obtained B. bigemina sequences showed a high similarity with those previously reported in GenBank with a percent identity ranging from 98.85 to 100%.

CONCLUSION

T. annulata was the most prevalent tick-borne pathogen in examined bovine specimens. The genetic diversity of markers used for identification of T. annulata and A. marginale should be highly considered.

First detection of Theileria parva in cattle from Cameroon in the absence of the main tick vector Rhipicephalus appendiculatus

A major risk factor for the spread of livestock diseases and their vectors is the uncontrolled transboundary movement of live animals for trade and grazing. Such movements constrain effective control of tick-transmitted pathogens, including Theileria parva. Only limited studies have been undertaken to identify ticks and tick-borne diseases (TTBDs) affecting cattle in central African countries, including Cameroon. We hereby report the collection of baseline data on the prevalence of T. parva in Cameroon through a countrywide cross-sectional survey, conducted in 2016, involving collection of blood samples from cattle from 63 sites across the five agro-ecological zones (AEZs) of the country. ELISA-based surveillance of infected cattle was performed on 479 randomly selected samples and revealed specific antibodies to T. parva in 22.7% and T. mutans in 41.1% of cattle. Screening of 1,340 representative DNA samples for the presence of T. parva identified 25 (1.86%) positives using a p104 antigen gene-based nested PCR assay. The positives were distributed across agro-ecological zones I, II, III and V. None of the p104 positive cattle exhibited clinical symptoms of East Coast fever (ECF). Using reverse line blot (RLB), 58 (4.3%) and 1,139 (85%) of the samples reacted with the T. parva and T. mutans oligonucleotide probes, respectively. This represents the first report of T. parva from Cameroon. Surprisingly, no Rhipicephalus appendiculatus ticks, the main vector of T. parva, were identified in a parallel study involving comprehensive morphological and molecular survey of tick species present in the country. Only two of the 25 p104 positive cattle were PCR-positive for the CD8+ T-cell target schizont-expressed antigen gene Tp1. Cloning and sequencing of Tp1 amplicons revealed sequence identity with the reference T. parva Muguga. This new finding raises serious concerns of a potential spread of ECF into the central African region.

Knowledge and perception on ticks and tick-borne diseases among veterinary medicine students from the North African countries of Algeria, Egypt, and Tunisia

Ticks are important vectors of both animal and human pathogens. The epidemiology of tick-borne diseases (TBDs) has dramatically changed in several regions in the world. As parasitology is a continuously growing field, assessing the knowledge of veterinary medicine students provides useful indicators and information on the level of intervention required to adapt parasitological courses to meet the demands in a changing world.

This study aimed to assess, in three North African veterinary education establishments, the basic parasitology knowledge of veterinary medicine students. Such a study is essential to build up core competencies regarding ticks and TBDs, and to suggest suitable adjustment measures to parasitology courses.

The present study was based on a self-administered and anonymous questionnaire on ticks and TBDs basic knowledge and perception. The survey was completed by 558 veterinary medicine students in Algeria, Egypt, and Tunisia in 2018. The students were divided into two groups: the “before” group – students who had not yet completed the parasitology course, and the “after” group – students who had already completed it.

In all studied countries, the “after” students' group gave significantly more correct answers (83.16%) than the “before” students' group (16.84%) (p < 0.001). Similarly, the percentage of “no answer” was higher in the “before” students' group (51.02%) compared to the “after” students' group (48.98%) (p < 0.001). The most frequent false answers provided by the “after” students' group regarded the number of tick species present in their own countries (5.14% of correct answers), and the most common tick species in their countries (18.11% of correct answers).

Almost 58.38% (216/370) of the “after” students' group knew that ticks transmit zoonotic pathogens to humans; among them, only 63 (29.17%) gave the correct names of the zoonotic diseases in their country.

Among the three countries, more than 80% of the “after” students' group thought that climate has an influences on ticks. According to this group, the most frequent factor that has influences on ticks' abundance is heat (53.02%).

As North African countries share several similitudes, we suggest creating a network of parasitological teachers where common teaching sources and resources could be developed for both teachers and students in the region. This network would allow the exchange of teaching approaches and materials to introduce harmonization into veterinary parasitological courses across North African countries. This is particularly important when considering the increasing incidence of ticks and TBDs in the region.

Review of clinical aspects, epidemiology and diagnosis of haemotropic Mycoplasma ovis in small ruminants: current status and future perspectives in tropics focusing on Malaysia

Mycoplasma ovis (formerly Eperythrozoon ovis) is an epierythrocytic parasitic bacterium of small ruminants known as haemotropic mycoplasma, which is transmitted mechanically by biting flies and contaminated instruments. Acute mycoplasmosis causes severe haemolytic anaemia and mortality in young animals. At the same time, chronic disease may produce mild anaemia and varying degrees of morbidity depending on several factors, including age, reproductive status, the plane of nutrition, immunological status and the presence of concurrent infection. Haemotropic Mycoplasma ovis is currently recognised as an emerging zoonotic pathogen which is widely distributed in the sheep and goat producing areas of tropics and subtropics, where the disease is nearly endemic. Human infection has been reported in pregnant women, immunocompromised patients and people exposed to animals and arthropods. The current diagnosis of haemoplasma relies on microscopic evaluation of Giemsa-stained blood smear and PCR. Although there are few published reports on the incidence of haemotropic Mycoplasma ovis infection of small ruminants in Malaysia, information on its prevalence, risk factors, severity and economic impacts is grossly inadequate. Therefore, a large-scale survey of small ruminant flocks is necessary to elucidate the current seroprevalence status and molecular characteristics of haemotropic M. ovis infection in Malaysia using ELISA and PCR sequencing technologies. In the future, surveillance programs, including vector forecast, quarantine, monitoring by periodic surveys and public enlightenment, will limit the internal and transboundary spread of M. ovis, enhance control efforts and mitigate production losses in Malaysia.

Molecular detection of Theileria spp. and Babesia ovis Infection in Sheep in Baneh, Iran

The purpose of the present study was to investigate the Theileria and Babesia infection in sheep using polymerase chain reaction (PCR) assay in Baneh, Iran. Theileria and Babesia are apicomplexan parasites that have both vertebral and invertebrate hosts. These protozoa, which are transmitted by tick vectors, are considered to be the most important causes of parasitic diseases in Iran.The detection methods of Babesia and Theileria spp. are morphological examination, serology tests, and more recently, molecular assays, such as PCR. In this study, a total of 66 blood samples were collected and analyzed using specific primers for Theileria annulata, T. ovis, T. lestoquardi, and Babesia ovis. Two PCR methods were used, namely semi-nested PCR and competitive PCR. Based on the results of the PCR assay of 66 sheep blood samples, B. ovis, T. ovis, T. lestoquardi, and T. annulata were detected in 57 (86.4%), 28 (42.4%), 0, and 16 (24%) cases, respectively. Detection of low levels of protozoan infection with high morbidity in the tested animals shows their status as a carrier that keeps the infection in the region and extends the protozoan life cycle. Another important factor is the geographical situation of Baneh as a border city since the hemoprotozoan infection is present in this region. Moreover, piroplasmida infection was found in Iraq and other neighboring provinces. Therefore, animal husbandry in Baneh is at the risk of infection with Babesia and Theileria. The collected data in this study are useful for reaching a better understanding of the epizootiology of theileriosis and babesiosis, in order to control and prevent the diseases in this region.

Interrupted Blood Feeding in Ticks: Causes and Consequences

Ticks are obligate hematophagous arthropods and act as vectors for a great variety of pathogens, including viruses, bacteria, protozoa, and helminths. Some tick-borne viruses, such as Powassan virus and tick-borne encephalitis virus, are transmissible within 15–60 min after tick attachment. However, a minimum of 3–24 h of tick attachment is necessary to effectively transmit bacterial agents such as Ehrlichia spp., Anaplasma spp., and Rickettsia spp. to a new host. Longer transmission periods were reported for Borrelia spp. and protozoans such as Babesia spp., which require a minimum duration of 24–48 h of tick attachment for maturation and migration of the pathogen. Laboratory observations indicate that the probability of transmission of tick-borne pathogens increases with the duration an infected tick is allowed to remain attached to the host. However, the transmission time may be shortened when partially fed infected ticks detach from their initial host and reattach to a new host, on which they complete their engorgement. For example, early transmission of tick-borne pathogens (e.g., Rickettsia rickettsii, Borrelia burgdorferi, and Babesia canis) and a significantly shorter transmission time were demonstrated in laboratory experiments by interrupted blood feeding. The relevance of such situations under field conditions remains poorly documented. In this review, we explore parameters of, and causes leading to, spontaneous interrupted feeding in nature, as well as the effects of this behavior on the minimum time required for transmission of tick-borne pathogens.

A genetic and immunological comparison of tick-resistance in beef cattle following artificial infestation with Rhipicephalus ticks

Host resistance to ticks can be explored as a possible approach of combating tick infestations to complement the existing unsustainable tick control methods. Thirty-six beef cattle animals were used, consisting of Angus, Brahman and Nguni breeds, with each breed contributing 12 animals. Half of the animals per breed were artificially challenged with Rhipicephalus microplus and the other half with R. decoloratus unfed larvae per animal. Skin biopsies and blood samples were collected pre-infestation and 12 h post-infestation from the feeding sites of visibly engorging ticks. The success rate of the ticks was high and had an influence even at the early time point. Increased lymphocytes and blood urea nitrogen levels as well as decreased levels of segmented neutrophils were observed in the Angus, which were the opposite of those in the Brahman and Nguni. The increase in cholesterol, which was highest in the Angus and lowest in the Nguni, may be due to altered protein metabolism. The expression profiles of genes TRAF6, TBP, LUM and B2M were significantly different among breeds. Five genes (CCR1, TLR5, TRAF6, TBP, BDA20) had increased or constant expression post-infestation, whereas the expression of CXCL8, IL-10 and TNF-α decreased or remained the same after tick challenge. Genes that showed variation are involved in discouraging long-term supply of blood meal to the tick and those associated with immune responses. The gene LUM is a potential biomarker for tick resistance in cattle. The response to infestation by the breeds was consistent across the tick species.

Do rainfall and tick burden affect the efficacy of pour-on formulations against Rhipicephalus (Boophilus) microplus?

Rhipicephalus (Boophilus) microplus is the most important livestock tick, causing economical losses especially in tropical and subtropical regions. Pour-on formulations using synthetic chemicals, remain the most farmer friendly conventional form of tick control method. Misuse of acaricides can lead to the emergence of resistance, residual chemicals in animal products, the poisoning of vertebrates and environment contamination. Despite the increase in the use of pour-on formulations, little is known regarding the therapeutic and residual efficacy of these products after the treated animals are exposed to rainfall. Moreover, information is scanty on whether efficacy is modulated by different levels of tick burden. Three studies were conducted. In the two first experiments, we evaluated the therapeutic and residual efficacies of commercial pour-on products (fluazuron 2.5 mg/kg and fipronil 1.0 mg/kg, respectively) on cattle naturally infested with R. (B.) microplus under the condition of simulated rainfall. In the third study, we investigated whether tick burden affects the efficacy of the drugs used a chemical control method involving three different formulations (Day 0: cypermethrin 5.0 mg/kg + chlorpyrifos 7.0 mg/kg + citronellal 0.5 mg/kg; Day 7: fluazuron 3.0 mg/kg + abamectin 0.5 mg/kg and Day 56: fipronil 1.0 mg/kg + fluazuron 3.0 mg/kg). Tick counts were performed on different days to assess efficacy. It was observed that the residual efficacy of the commercial formulations was lower on animals that received simulated rain. In addition, therapeutic and residual efficacies of the products were reduced in the group of animals with a high tick burden of R. (B.) microplus. In conclusion, rainfall decreases the efficacy of acaricides. Also, the tick burden must be considered when selecting a pour-on formulation.

Pentaplex PCR assay for rapid differential detection of Babesia bigemina, Theileria annulata, Anaplasma marginale and Trypanosoma evansi in cattle

A multiplex PCR (mPCR) assay for simultaneous detection and differentiation of four major haemoparasites in crossbred cattle was established using parasite specific genomic DNA and four sets of primer pairs targeting AMA-1, Tams1, MSP5 and VSG genes of Babesia bigemina, Theileria annulata, Anaplasma marginale and Trypanosoma evansi generating precise amplicons of 448, 156, 382 and 110 bp, respectively. An internal amplification control, 202 bp bovine β-casein gene fragment, was simultaneously amplified with four target genes to avoid false-negative results. The sensitivity of mPCR was 3.44 × 10², 5.9 × 10³, 2.88 × 10² and 3.3 × 10³ copies for B. bigemina, T. annulata, A. marginale and T. evansi, respectively. mPCR of cattle clinical samples (n = 516), suspected for haemoparasites, revealed single haemoparasitic infection in 279 (54.06%) cases, whereas mixed infection was recorded in 54 (10.46%) samples. In clinical samples, coinfection with T. annulata and A. marginale was the most common. The findings of mPCR were consistent with uniplex PCR under field conditions except for subtle variations in A. marginale infection. Overall, the mPCR assay represents an economical, reproducible and robust diagnostic tool for concurrent detection of cattle haemoparasites and large scale epidemiological studies.

Genetic diversity, piroplasms and trypanosomes in Rhipicephalus microplus and Hyalomma anatolicum collected from cattle in northern Pakistan

The two most important tick species in Pakistan are Rhipicephalus microplus and Hyalomma anatolicum. When associated with cattle, these have one or three host life cycles, respectively, with potential implications for their population genetics and for their vector role in the transmission of pathogens. To compare the two tick species in this context with molecular-phylogenetic methods, during the present study 123 ticks were collected from cattle in northern Pakistan. Two mitochondrial markers of 36 ticks were molecularly analyzed. All 11 R. microplus specimens had identical cox1 haplotypes, whereas the 25 H. anatolicum specimens had nine cox1 haplotypes. The latter belonged to two distinct phylogenetic lineages with high support. However, in the 16S rRNA gene these differences were less evident. Among the 113 ticks molecularly analyzed for tick-borne protozoa, the sequence of Babesia occultans was successfully amplified from two specimens of H. anatolicum. Theileria annulata was present in both R. microplus (10.4%) and H. anatolicum (27.3%), with significantly higher prevalence rate in the latter species. Only one tick, a H. anatolicum female, was positive in the PCR detecting Trypanosoma spp. Sequencing revealed the presence of a new genotype, with the closest phylogenetic relationship to stercorarian trypanosomes (in particular, to a tick-associated Trypanosoma sp. from Japan). In conclusion, the above differences between R. microplus and H. anatolicum may be partly related to their life cycles involving one host or three hosts, respectively. Among the others, host switching (reducing chances of inbreeding) and shorter periods spent on-host (reducing gene flow between cattle herds) are supposed to be important drivers of cox1 gene diversification in case of H. anatolicum as a three host tick species. These results highlight the importance of studying differences in intraspecific genetic diversity and piroplasm burdens between one host and three host ticks in the local scale. In addition, a Trypanosoma sp. molecularly identified in H. anatolicum is reported here for the first time from South Asia, deserving further evaluation concerning its host and vector species.

Preliminary investigation of acaricidal activity of leaf extract of Nicotiana tabacum on dog tick Rhipicephalus sanguineus

BACKGROUND AND AIM

Tick infestation of domestic animals remains a major constraint to livestock productivity across all agro-ecological zones most especially in small animal practice. The most common method of tick control is the use of synthetic acaricide. However, a widespread increase of acaricidal resistance, scarcity and high cost of acaricides especially to farmers of low-income earnings in developing countries support the need for alternative tick control methods. Among the alternative methods for tick control is herbal therapy. In this study, we investigated the acaricidal activity of methanol and N-hexane leaf extracts of Nicotiana tabacum against dog ticks - Rhipicephalus sanguineus.

MATERIALS AND METHODS

Larvicidal and adulticidal activity of N. tabacum leaf extract were examined on the dog tick - R. sanguineus in an in vitro experiment using larval packet test and adult immersion test respectively. Phytochemical and Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the leaf extract were also carried out using standard methods.

RESULTS

We observed a tick mortality rate that was concentration-dependent. However, N-hexane extract showed a higher significant acaricidal effect than methanol extract. Lethal dose (LD50) of N. tabacum was 0.06. High quantity of terpenoids was obtained from N. tabacum. Lower tick glutathione S-transferase observed with varying concentration of N. tabacum. GC-MS revealed Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S) - Nicotine, Citronellyl propionate, Crotonaldehyde, Lavandulyl acetate, trans-Phytol and Amitrole (3-Amino-1, 2, 4-triazole) in N. tabacum.

CONCLUSION

Both methanol and N-hexane leaf extracts of N. tabacum exhibited observable acaricidal property against the larvae and adult R. sanguineus of dog.

Characterization of an iron-inducible Haemaphysalis longicornis tick-derived promoter in an Ixodes scapularis-derived tick cell line (ISE6)

Background

Ticks are important vectors of disease-causing pathogens. With the rise of resistance to chemical acaricides, alternative methods in tick control are warranted. Gene manipulation has been successful in controlling mosquitoes and mosquito-borne diseases and is now looked upon as a candidate method to control ticks and tick-borne pathogens. Our previous study has identified the actin and ferritin promoter regions in the Haemaphysalis longicornis tick.

Results

Here, the ferritin-derived promoter from the H. longicornis tick was characterized in silico, and the core promoter sequences and some of its important components were identified. Several truncations of the promoter region were created and inserted to a reporter plasmid to determine the important components for its activity. The activities of the truncated promoters on the Ixodes scapularis tick cell line (ISE6) were measured via a dual luciferase assay using experimental and control reporter genes. To induce the promoter’s activity, transfected ISE6 cells were exposed to ferrous sulfate. The 639 nucleotides truncated promoter showed the highest activity on ISE6 cells when exposed to 1 mM ferrous sulfate.

Conclusion

In this study, we characterized an iron-inducible tick promoter that could be a valuable tool in the development of a gene-manipulation system to control ticks and tick-borne pathogens.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3574-9) contains supplementary material, which is available to authorized users.

Molecular detection and genetic characterisation of pathogenic Theileria, Anaplasma and Ehrlichia species among apparently healthy sheep in central and western Kenya

Tick-borne diseases (TBDs) caused by Theileria, Babesia, Anaplasma and Ehrlichia species are common in tropical and subtropical regions. In this study, we investigated the presence and genetic diversity of Theileria spp., Anaplasma ovis, B. ovis, E. ruminantium and Anaplasma spp. in sheep from the Machakos and Homa Bay counties of Kenya. In order to improve the diagnosis and control of ovine TBDs, a total of 76 blood samples from apparently healthy sheep were screened using a polymerase chain reaction (PCR). The assays were conducted using primers based on Theileria spp. 18S rRNA, Anaplasma ovis Major surface protein-4 (AoMSP4), B. ovis 18S rRNA, E. ruminantium pCS20 and Anaplasma spp. 16S rRNA. The overall infection rates for Theileria spp., A. ovis, E. ruminantium and Anaplasma spp. were 39/76 (51.3%), 26/76 (34.2%), 6/76 (7.9%) and 31/76 (40.8%), respectively. The overall co-infection was 47/76 (61.8%). All Theileria spp. positive samples were confirmed to be of Theileria ovis on sequencing. A phylogenetic analysis of the 18S rRNA gene sequences of T. ovis revealed that all isolates of this study clustered with T. ovis sequences extracted from the GenBank suggesting this gene is highly conserved. E. ruminantium pCS20 sequences were in the same clade on the phylogenetic tree. However, three AoMSP4 sequences from this study appeared in the same clade, while one sequence formed a separate branch revealing genetic divergence. The 16S rRNA sequencing revealed uncharacterised Anaplasma spp. and A. ovis. The phylogenetic analyses of the uncharacterised Anaplasma spp. revealed that the two sequences from this study appear in an independent clade from other sequences extracted from the GenBank. This study provides important information regarding the occurrence of tick-borne pathogens and their degree of genetic diversity among sheep in Kenya, which is useful for the diagnosis and control of TBDs.

Molecular detection and characterization of tick-borne protozoan and rickettsial pathogens isolated from cattle on Pemba Island, Tanzania

Tick-borne diseases cause significant losses to livestock production in tropical and subtropical regions. In Tanzania, detailed studies on tick-borne pathogens in cattle using sensitive molecular detection methods are scarce. In this study, we investigated the occurrence of Theileria spp., Babesia spp., Anaplasma spp. and Ehrlichia spp. in 245 blood samples collected from cattle on Pemba Island, Tanzania. We used polymerase chain reaction (PCR) and gene sequencing to detect and identify pathogens. PCR screening revealed overall infection rates of 62.4% for Theileria spp., 17.6% for Babesia bigemina, 15.9% for Anaplasma marginale, 7.4% for Ehrlichia ruminantium and 4.5% for Babesia bovis. Further analysis using sequences of Theileria spp. 18S rRNA revealed infection of cattle with Theileria mutans (68.6%), Theileria taurotragi (48.4%), Theileria parva (41.2%), and Theileria ovis (1.9%). Co-infections of cattle, with up to six tick-borne pathogens, were revealed in 46.9% of the samples. Sequence analysis indicated that T. parva p104, E. ruminantium pCS20 and A. marginale MSP-5 genes are conserved among cattle blood samples in Pemba, with 99.3%-100%, 99.6%-100% and 100% sequence identity values, respectively. In contrast, the B. bigemina RAP-1a and B. bovis SBP-2 gene sequences were relatively diverse with 99.5%-99.9% and 66.4%-98.7% sequence identity values respectively. The phylogenetic analyses revealed that T. parva p104, E. ruminantium pCS20 and A. marginale MSP-5 gene sequences clustered in the same clade with other isolates from other countries. In contrast, the B. bigemina RAP-1 and B. bovis SBP-2 gene sequences showed significant differences in the genotypes, as they appeared in separate clades. This study provides important data for understanding the epidemiology of tick-borne diseases, and is expected to improve the approach for diagnosis and control of tick-borne diseases in Tanzania.

Strategies for the control of Rhipicephalus microplus ticks in a world of conventional acaricide and macrocyclic lactone resistance

Infestations with the cattle tick, Rhipicephalus microplus, constitute the most important ectoparasite problem for cattle production in tropical and subtropical regions worldwide, resulting in major economic losses. The control of R. microplus is mostly based on the use of conventional acaricides and macrocyclic lactones. However, the intensive use of such compounds has resulted in tick populations that exhibit resistance to all major acaricide chemical classes. Consequently, there is a need for the development of alternative approaches, possibly including the use of animal husbandry practices, synergized pesticides, rotation of acaricides, pesticide mixture formulations, manual removal of ticks, selection for host resistance, nutritional management, release of sterile male hybrids, environmental management, plant species that are unfavourable to ticks, pasture management, plant extracts, essential oils and vaccination. Integrated tick management consists of the systematic combination of at least two control technologies aiming to reduce selection pressure in favour of acaricide-resistant individuals, while maintaining adequate levels of animal production. The purpose of this paper is to present a current review on conventional acaricide and macrocyclic lactone resistance for better understanding and control of resistant ticks with particular emphasis on R. microplus on cattle.

Prevalence of tick-borne haemoparasites in small ruminants in Turkey and diagnostic sensitivity of single-PCR and RLB

Background

Tick-borne haemoparasitic diseases (TBHDs), caused by Theileria, Babesia, Anaplasma and Ehrlichia, are common in regions of the world where the distributions of host, pathogen and vector overlap. Many of these diseases threaten livestock production and some also represent a concern to human public health. The primary aim of this study was to determine the prevalence of the above-mentioned pathogens in a large number of blood samples (n = 1979) collected from sheep (n = 1727) and goats (n = 252) in Turkey. A secondary aim was to assess the diagnostic sensitivity of a number of species-specific polymerase chain reaction (PCR) tests and the reverse line blotting (RLB) assay. DNA samples were screened using species-specific PCR for the presence of Theileria ovis, Theileria sp. MK, T. lestoquardi, T. uilenbergi, T. luwenshuni, Babesia ovis, Anaplasma ovis and A. phagocytophilum while RLB was undertaken to test for the presence of all known Theileria, Babesia, Anaplasma and Ehrlichia species. The diagnostic sensitivity of these two approaches was then compared in terms of their ability to detect single species and mixed infections.

Results

Overall, 84 and 74.43% of the small ruminants sampled were identified as hosting one or more pathogen(s) by species-specific PCR and RLB respectively. The presence of Theileria sp. OT1, T. luwenshuni and T. uilenbergi in Turkey was revealed for the first time while the presence of Babesia motasi, B. crassa and T. separata in Turkish small ruminants was confirmed using molecular methods. A high prevalence of mixed infection was evident, with PCR and RLB approaches indicating that 52.24 and 35.42% of animals were co-infected with multiple species, respectively. More than 80% of the mixed infections contained T. ovis and/or A. ovis. The RLB approach was found to be capable of detecting mixed infections with species such as Theileria sp. OT1, Theileria sp. OT3, T. separata, B. crassa and Babesia spp.

Conclusion

The results indicated that pathogens causing TBHDs are highly prevalent in sheep and goats in Turkey. The diagnostic sensitivity of species-specific single PCR was generally higher than that of RLB. However, the latter approach was still capable of identifying a high proportion of individuals containing mixed-species infections. The use of species-specific single PCR is recommended to accurately estimate pathogen prevalence and to identify co-infected hosts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2151-3) contains supplementary material, which is available to authorized users.

Surveillance of ticks and associated pathogens in free-ranging Formosan pangolins (Manis pentadactyla pentadactyla)

Chinese pangolins are critically endangered insectivorous mammals distributed in several South and Southeast Asian countries. In recent years, there has been an increase in spread of tick-borne diseases in both humans and animals worldwide. Currently, limited information is available on ticks and associated pathogens infesting pangolins. The objective of the present study was to survey ticks and associated pathogens in the Formosan pangolin population in Southeastern Taiwan. Free-ranging Formosan pangolins captured during ecological survey were examined for the presence of ticks. DNA extracted from these ticks was used to identify the tick species and also to detect the tick-borne pathogens, by molecular methods. In the present study, we found 25% (13/52) of pangolins captured during 2012-2014 infested with ixodid ticks. A total of 21 ticks were collected and 3 species were identified: Haemaphysalis hystricis (14/21), Haemaphysalis formosensis (2/21) and Amblyomma testudinarium (5/21). We detected four different tick-borne pathogens, where one was identical to Anaplasma sp. strain An.H1446 while others showed close resemblance to Rickettsia conorii subsp. caspia A-167, Ehrlichia sp. TC251-2 and Cytauxzoon spp., respectively. The present study is the first survey of ticks infesting the free-ranging Chinese pangolins and pathogens harboured by these ticks. This information is important to know the diversity of ticks and tick-borne pathogens, and its conservation significance to pangolins and other sympatric wildlife. Important future step should be regular surveillance of ticks and tick-borne diseases at human-domestic animals-wildlife interface, which can provide a useful insight into the dynamics of these pathogens and can help control and prevent outbreak of zoonoses.

Ixodes scapularis Tick Saliva Proteins Sequentially Secreted Every 24 h during Blood Feeding

Ixodes scapularis is the most medically important tick species and transmits five of the 14 reportable human tick borne disease (TBD) agents in the USA. This study describes LC-MS/MS identification of 582 tick- and 83 rabbit proteins in saliva of I. scapularis ticks that fed for 24, 48, 72, 96, and 120 h, as well as engorged but not detached (BD), and spontaneously detached (SD). The 582 tick proteins include proteases (5.7%), protease inhibitors (7.4%), unknown function proteins (22%), immunity/antimicrobial (2.6%), lipocalin (3.1%), heme/iron binding (2.6%), extracellular matrix/ cell adhesion (2.2%), oxidant metabolism/ detoxification (6%), transporter/ receptor related (3.2%), cytoskeletal (5.5%), and housekeeping-like (39.7%). Notable observations include: (i) tick saliva proteins of unknown function accounting for >33% of total protein content, (ii) 79% of proteases are metalloproteases, (iii) 13% (76/582) of proteins in this study were found in saliva of other tick species and, (iv) ticks apparently selectively inject functionally similar but unique proteins every 24 h, which we speculate is the tick's antigenic variation equivalent strategy to protect important tick feeding functions from host immune system. The host immune responses to proteins present in 24 h I. scapularis saliva will not be effective at later feeding stages. Rabbit proteins identified in our study suggest the tick's strategic use of host proteins to modulate the feeding site. Notably fibrinogen, which is central to blood clotting and wound healing, was detected in high abundance in BD and SD saliva, when the tick is preparing to terminate feeding and detach from the host. A remarkable tick adaptation is that the feeding lesion is completely healed when the tick detaches from the host. Does the tick concentrate fibrinogen at the feeding site to aide in promoting healing of the feeding lesion? Overall, these data provide broad insight into molecular mechanisms regulating different tick feeding phases. These data set the foundation for in depth I. scapularis tick feeding physiology and TBD transmission studies.

Effect of Euphorbia cyparissias ointments on acanthosis

BACKGROUND

A pharmaco-chemical investigation of the Euphorbia cyparissias plant was justified by its known multiple therapeutic valences. Numerous components from extracts and latex of Euphorbiacae were identified, revealing a large plant family with a polyvalent therapeutic activity.

MATERIALS AND METHODS

The aim of the study was to assess the skin tolerance level to irritation on different testing concentrations, of Euphorbia cyparissias extracts and ointments. Study was accomplished in rats and dogs, with the identification of all possible skin injuries and histological changes, after a simple patch test methodology.

RESULTS

Ointment dermatological testing on rats, proved to be bearable on epilated skin at concentrations of 1, 2 and 5%. Ointments and mother tincture with higher concentrations (10% and 20%), led to irritation and cutis damages, and this was revealed through histology.

CONCLUSION

Ointment tested on dog's skin was tolerable for epilated skin to concentrations of 1, 2 and/or 5%, additional testing on human volunteers confirmed the same situation.