Recent Progress on Tick-Borne Animal Diseases of Veterinary and Public Health Significance in China.

Ticks and tick-borne diseases pose a growing threat to human and animal health, which has brought great losses to livestock production. With the continuous expansion of human activities and the development of natural resources, there are more and more opportunities for humans to contract ticks and tick-borne pathogens. Therefore, research on ticks and tick-borne diseases is of great significance. This paper reviews recent progress on tick-borne bacterial diseases, viral diseases, and parasitic diseases in China, which provides a theoretical foundation for the research of tick-borne diseases.

CHANGES IN THE LEVELS OF THEILERIA ORIENTALIS IKEDA TYPE INFECTION IN HAEMAPHYSALIS LONGICORNIS NYMPHS OVER A SIX-MONTH PERIOD.

This study aimed to investigate whether the infection intensity of Theileria orientalis Ikeda type organisms within Haemaphysalis longicornis larvae and nymph stages fluctuated over 6 mo after feeding as larvae on infected calves in the field. Naïve larvae, hatched from eggs, were fed on infected calves for 5 days while contained within cotton socks glued over the calves' ears. Larvae were first sampled immediately post-feeding and then sampled every 3 wk for 23 wk in total, after molting to nymphs. All larvae and nymphs were tested for T. orientalis Ikeda organisms using quantitative PCR. The qPCR results showed that the infection intensity of Haemaphysalis longicornis larvae and nymphs was not constant over the sampling period, and after initially dropping after molting to nymphs, it then rose with fasting to a maximum at 17 and 23 wk post-feeding. The significant rise in T. orientalis Ikeda organisms observed at 23 wk postfeeding may explain why more severe clinical cases of bovine theileriosis in New Zealand are seen in the spring when nymphs are the predominant instar questing.

Stray Mexico origin cattle captured crossing into Southern Texas carry Babesia bovis and other tick-borne pathogens.

Cattle fever ticks, Rhipicephalus microplus and R. annulatus have been eradicated from the United States and inspectors from the U.S. Department of Agriculture (USDA), Animal Plant Health Inspection Service (APHIS), Cattle Fever Tick Eradication Program (CFTEP) monitor the quarantine zone along the Texas border to prevent the introduction of livestock carrying cattle fever ticks from Mexico. Stray livestock apprehended by CFTEP in the zone are checked for ticks and tested for infectious disease-causing pathogens but are not evaluated for evidence of infection with tick-borne pathogens. We tested blood samples collected from stray cattle by CFTEP inspectors for evidence of infection with tick-borne pathogens. As a comparison group representing U.S. resident cattle, we tested blood samples that had been sent to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for unrelated testing. Both sets of blood samples were evaluated using the same specific and broad-spectrum PCR assays. For the border cattle the overall prevalence of infection with one or more tick-borne pathogen was 58.5 % (79/135) with many co-infections, including 30 cattle positive for Babesia bovis and/or Babesia bigemina (22.2 %) and 77 cattle positive for Anaplasma marginale (57 %), three of these animals were also positive for Borrelia theileri. No resident cattle represented by the TVMDL samples were infected with either of the Babesia spp., or with Borrelia theileri, but three were positive for Theileria orientalis and 7.3 % (7/96) were positive for A. marginale. These data show that cattle originating in Mexico have a higher prevalence of infection with tick-borne pathogens relative to resident U.S. cattle and specifically, a proportion are infected with bovine Babesia, which is absent from U.S. cattle populations. Consequently, these stray cattle may be a reservoir of tick-borne pathogens and if populations of Boophilus ticks become reestablished in areas where they had previously been eradicated, could pose a significant risk to the U.S. Cattle industry.

Trends and Opportunities in Tick-Borne Disease Geography.

Tick-borne diseases are a growing problem in many parts of the world, and their surveillance and control touch on challenging issues in medical entomology, agricultural health, veterinary medicine, and biosecurity. Spatial approaches can be used to synthesize the data generated by integrative One Health surveillance systems, and help stakeholders, managers, and medical geographers understand the current and future distribution of risk. Here, we performed a systematic review of over 8,000 studies and identified a total of 303 scientific publications that map tick-borne diseases using data on vectors, pathogens, and hosts (including wildlife, livestock, and human cases). We find that the field is growing rapidly, with the major Ixodes-borne diseases (Lyme disease and tick-borne encephalitis in particular) giving way to monitoring efforts that encompass a broader range of threats. We find a tremendous diversity of methods used to map tick-borne disease, but also find major gaps: data on the enzootic cycle of tick-borne pathogens is severely underutilized, and mapping efforts are mostly limited to Europe and North America. We suggest that future work can readily apply available methods to track the distributions of tick-borne diseases in Africa and Asia, following a One Health approach that combines medical and veterinary surveillance for maximum impact.

Molecular evidence indicts Haemaphysalis leachi (Acari: Ixodidae) as the vector of Babesia rossi in dogs in Nigeria, West Africa.

Babesia rossi is the most pathogenic among the large canine babesias and it is the major cause of canine babesisosis in Nigeria. In South Africa it is transmitted by Haemaphysalis elliptica however, its putative vector in Nigeria where Rhipicephalus sanguineus is the most prevalent tick on dogs compared to Haemaphysalis species has not been ascertained. The incongruity between tick distribution and the frequent detection of B. rossi in Nigeria motivated this investigation to identify the local vector(s) of B. rossi. A total of 3805 ticks were collected from 363 naturally infested dogs from different parts of Nigeria. Of these numbers, 758 engorged female ticks; Rh. sanguineus (n = 660) and H. leachi (n = 98) were incubated for oviposition and hatching. After the completion of egg laying, Rh. sanguineus (n = 69) and H. leachi (n = 24) and their resulting progenies were screened for the presence of B. rossi DNA using a nested PCR targeting the 693 bp of the 18S rRNA gene of Babesia spp. Amplification and sequencing of B. rossi DNA was successful in the adults of H. leachi and their resulting egg and larval progenies but not in the adult Rh. sanguineus and progenies. The B. rossi DNA sequences from the H. leachi and their progenies have 99-100 % identity to each other and 98-99 % identical to sequences of B. rossi in GenBank (GenBank: MH143395.1), thus confirming transovarian passage. This evidence confirms for the first time following the reclassification of H. leachi to H. elliptica in South Africa the role of H. leachi in the transmission of B. rossi in dogs in Nigeria.

Response of Leucine-Rich Repeat Domain-Containing Protein in Haemaphysalis longicornis to Babesia microti Infection and Its Ligand Identification.

Haemaphysalis longicornis is a blood-feeding hard tick known for transmitting a variety of pathogens, including Babesia How the parasites in the imbibed blood become anchored in the midgut of ticks is still unknown. Leucine-rich repeat domain (LRR)-containing protein, which is associated with the innate immune reaction and conserved in many species, has been detected in H. longicornis and has previously been indicated in inhibiting the growth of Babesia gibsoni However, the detailed mechanism is unknown. In this study, one of the ligands for LRR from H. longicornis (HlLRR) was identified in Babesia microti, designated BmActin, using glutathione transferase (GST) pulldown experiments and immunofluorescence assays. Moreover, RNA interference of HlLRR led to a decrease in the BmActin mRNA expression in the midgut of fully engorged ticks which fed on B. microti-infected mice. We also found that the expression level of the innate immune molecules in H. longicornis, defensin, antimicrobial peptides (AMPs), and lysozyme, were downregulated after the knockdown of HlLRR. However, subolesin expression was upregulated. These results indicate that HlLRR not only recognizes BmActin but may also modulate innate immunity in ticks to influence Babesia growth, which will further benefit the development of anti-Babesia vaccines or drugs.

Epidemiological link between canine monocytic ehrlichiosis caused by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto in Argentina.

In this work, we analyze data that support an epidemiological link between cases of canine monocytic ehrlichiosis (CME) by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto as vector in an endemic area for this tick in Argentina. In a blood sample of a 1-year-old toy poodle with CME compatible clinical signs, which showed CME typical morulae in monocytes in Giemsa-stained blood smear, DNA of E. canis was detected by PCR. Further, DNA of E. canis was also detected in a female of R. sanguineus s.s. collected on the infected dog. Rhipicephalus sanguineus s.s. is the only member of the R. sanguineus group that prevails in the study area. The results of this study suggest that R. sanguineus s.s. may play a more important role in the transmission of E. canis than it was assumed so far. The epidemiological link between CME cases and R. sanguineus s.s. as vector in temperate areas of Argentina described in this work contrast previous studies which found that R. sanguineus sensu lato "tropical lineage" (which is absent in the study area) is competent to transmit E. canis but not R. sanguineus s.s.

Prevalence and distribution of pathogen infection and permethrin resistance in tropical and temperate populations of Rhipicephalus sanguineus s.l. collected worldwide.

The brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.) Latreille (Acari: Ixodidae), is a peridomestic, cosmopolitan parasite of dogs known to vector numerous pathogens of veterinary and medical importance. Recent phylogenetic analyses separate this tick into temperate and tropical lineages. Populations of Rh. sanguineus s.l. have been reported to exhibit sodium channel target site insensitivity to permethrin and etofenprox, which is likely due to the prolonged use of pyrethroids against many pests in and around the home. In this study, populations collected in the Caribbean, Africa, Asia, Europe and North America, were tested to identify the distribution of a known resistance mechanism, pathogen-vector interactions and phylogeny in relation to latitude. Using molecular assays, populations from 29 distinct locations were simultaneously geographically typed and screened for bacterial infection by Rickettsia, Ehrlichia, Babesia and Hepatozoon species, and for the presence of a sodium channel single nucleotide polymorphism known to confer permethrin resistance. Implications of these results on Rh. sanguineus s.l. management in association with geographical distribution will be discussed.

Scarcity of Hepatozoon americanum in Gulf Coast tick vectors and potential for cultivating the protozoan.

American canine hepatozoonosis (ACH) is a debilitating tick-borne disease characterized by pyrexia, body wasting, myopathy, mucopurulent ocular discharge, and periosteal proliferation. The causative agent, Hepatozoon americanum, is an apicomplexan that utilizes the Gulf Coast tick, Amblyomma maculatum, as its definitive host and vector. Unlike most tick-borne disease agents, H. americanum is not transmitted via a tick bite, but is transmitted when canids ingest a tick vector that contains sporulated oocysts within the tick hemocoel or paratenic hosts with cystozoites. Our understanding of H. americanum prevalence is based on its detection in the intermediate host, wild or domestic canids, with domestic canids often showing clinical signs at the time of diagnosis. The frequency of H. americanum in A. maculatum, on the other hand, is unknown; this gap in our knowledge hinders our understanding of transmission risk. Furthermore, current diagnostic assays are limited in efficacy, and serologic assays are not widely available. To begin to address gaps in our knowledge, we developed a TaqMan® multiplex qPCR assay for H. americanum detection in A. maculatum tick extracts and evaluated infection rates in questing adult A. maculatum. Additionally, we used a co-culture system to expose H. americanum stages to host cells for in vitro development. Results from qPCR analysis of over 500 tick extracts revealed no positive samples; this suggests both low transmission risk by adult Gulf Coast tick ingestion in the sampled areas, and that surveillance should be focused in areas where ACH has been diagnosed at higher frequencies. Hepatozoon americanum was detectable by qPCR in co-culture of an infected canine buffy coat with ISE6 (Ixodes scapularis embryonic) tick cells, and microscopic examination of samples from those days revealed some structures that were suspicious for developing stages. These data are a starting point for future work to advance our understanding of H. americanum transmission and mechanisms of disease in canids with ACH.

Molecular evidence confirms occurrence of Rhipicephalus microplus Clade A in Kenya and sub-Saharan Africa.

BACKGROUND: The tick vector Rhipicephalus microplus which transmits Babesia spp. and rickettsial pathogens has not been reported in Kenya since 1998. More recently, the pathogenic Babesia bovis has been detected in cattle blood DNA. The status of R. microplus in Kenya remains unknown. This study employed morphological and molecular tools to characterize R. microplus originating from Kenya and assess the genetic relationships between Kenyan and other African R. microplus genotypes. METHODS: Ticks were collected in south-eastern Kenya (Kwale County) from cattle and characterized to investigate the existence of R. microplus. Genetic and phylogenetic relationships between the Kenyan and other annotated R. microplus reference sequences was investigated by analysis of the cytochrome c oxidase subunit 1 (cox1) gene. To further characterize Kenyan ticks, we generated low coverage whole genome sequences of two R. microplus, one R. decoloratus and R. appendiculatus. A B. bovis specific TaqMan probe qPCR assay was used to detect B. bovis in gDNA from R. microplus ticks. RESULTS: Occurrence of R. microplus was confirmed in Kwale County, Kenya. The Kenyan R. microplus cox1 sequences showed very high pairwise identities (> 99%) and clustered very closely with reference African R. microplus sequences. We found a low genetic variation and lack of geographical sub-structuring among the African cox1 sequences of R. microplus. Four complete mitochondrial (mt) genomes for two R. microplus, one R. decoloratus and one R. appendiculatus were assembled from next generation sequence data. The mitochondrial genome sequences of the two Kenyan R. microplus ticks clustered closely with reference genome sequences from Brazil, USA, Cambodia and India forming R. microplus Clade A. No B. bovis was detected in the Kwale R. microplus DNA. CONCLUSIONS: These findings confirm the presence of R. microplus in Kenya and suggest that R. microplus Clade A is prevalent in cattle in sub-Saharan Africa. These and other recent findings of widespread occurrence of R. microplus in Africa provide a strong justification for urgent surveillance to determine and monitor the spread of R. microplus and vector competence of Boophilus ticks for B. bovis in Africa, with the ultimate goal of strategic control.

Molecular detection of pathogens in ticks and fleas collected from companion dogs and cats in East and Southeast Asia.

BACKGROUND: Ticks and fleas are considered amongst the most important arthropod vectors of medical and veterinary concern due to their ability to transmit pathogens to a range of animal species including dogs, cats and humans. By sharing a common environment with humans, companion animal-associated parasitic arthropods may potentially transmit zoonotic vector-borne pathogens (VBPs). This study aimed to molecularly detect pathogens from ticks and fleas from companion dogs and cats in East and Southeast Asia. METHODS: A total of 392 ticks and 248 fleas were collected from 401 infested animals (i.e. 271 dogs and 130 cats) from China, Taiwan, Indonesia, Malaysia, Singapore, Thailand, the Philippines and Vietnam, and molecularly screened for the presence of pathogens. Ticks were tested for Rickettsia spp., Anaplasma spp., Ehrlichia spp., Babesia spp. and Hepatozoon spp. while fleas were screened for the presence of Rickettsia spp. and Bartonella spp. RESULT: Of the 392 ticks tested, 37 (9.4%) scored positive for at least one pathogen with Hepatozoon canis being the most prevalent (5.4%), followed by Ehrlichia canis (1.8%), Babesia vogeli (1%), Anaplasma platys (0.8%) and Rickettsia spp. (1%) [including Rickettsia sp. (0.5%), Rickettsia asembonensis (0.3%) and Rickettsia felis (0.3%)]. Out of 248 fleas tested, 106 (42.7%) were harboring at least one pathogen with R. felis being the most common (19.4%), followed by Bartonella spp. (16.5%), Rickettsia asembonensis (10.9%) and "Candidatus Rickettsia senegalensis" (0.4%). Furthermore, 35 Rhipicephalus sanguineus ticks were subjected to phylogenetic analysis, of which 34 ticks belonged to the tropical and only one belonged to the temperate lineage (Rh. sanguineus (sensu stricto)). CONCLUSION: Our data reveals the circulation of different VBPs in ticks and fleas of dogs and cats from Asia, including zoonotic agents, which may represent a potential risk to animal and human health.

A tick cell line as a powerful tool to screen the antimicrobial susceptibility of the tick-borne pathogen Anaplasma marginale.

Anaplasma marginale is the causative agent of the severe bovine anaplasmosis. The tick Rhipicephalus microplus is one of the main vectors of A. marginale in tropical and subtropical regions of the world. After the tick bite, the bacterium invades and proliferates within the bovine erythrocytes leading to anemia, impairment of milk production and weight loss. In addition, infection can cause abortion and high mortality in areas of enzootic instability. Immunization with live and inactivated vaccines are employed to control acute bovine anaplasmosis. However, they do not prevent persistent infection. Consequently, infected animals, even if immunized, are still reservoirs of the bacterium and contribute to its dissemination. Antimicrobials are largely employed for the prophylaxis of bovine anaplasmosis. However, they are often used in sublethal doses which may select pre-existing resistant bacteria and induce genetic or phenotypic variations. Therefore, we propose a new standardized in vitro assay to evaluate the susceptibility of A. marginale strains to different antimicrobials. This tool will help health professionals to choose the more adequate treatment for each herd which will prevent the selection and spread of resistant strains. For that, we initially evaluated the antimicrobial susceptibility of two field isolates of A. marginale (Jaboticabal and Palmeira) infecting bovines. The least susceptible strain (Jaboticabal) was used for the standardization of an antimicrobial assay using a culture of Ixodes scapularis-derived tick cell line, ISE6. Results showed that enrofloxacin (ENRO) at 0.25, 1 or 4 µg/mL and oxytetracycline (OTC) at 4 or 16 µg/mL are the most efficient treatments, followed by OTC at 1 µg/mL and imidocarb dipropionate (IMD) at 1 or 4 µg/mL. In addition, this proposed tool has technical advantages compared to the previously established bovine erythrocyte culture. Thereby, it may be used to guide cattle farmers to the correct use of antimicrobials. The choice of the most suitable antimicrobial is essential to eliminate persistent infections, prevent the spread of resistant strains and help controlling of bovine anaplasmosis.

Tick-borne pathogens and their vectors in Kazakhstan - A review.

Tick-borne diseases (TBDs), in particular Crimean-Congo hemorrhagic fever (CCHF) and tick-borne encephalitis (TBE), have been found to be expanding beyond their traditional geographic locations in Kazakhstan, which led to increased awareness and concern against TBDs in recent years. The tick fauna of Kazakhstan includes more than 30 species of human-biting ixodid ticks, recognized as carriers of a number of dangerous infectious pathogens that cause CCHF, TBE, tularemia, tick-borne rickettsioses and Lyme borreliosis. This paper presents the current knowledge of the main vectors of tick-borne pathogens (TBP) occurring in Kazakhstan, as well as a review of recent studies of ticks performed with the use of molecular methods being currently developed and widely utilized by Kazakh epidemiologists.

Theileria orientalis Ikeda in host-seeking Haemaphysalis longicornis in Virginia, U.S.A.

The Asian longhorned tick, Haemaphysalis longicornis, has recently become established in the United States. In East Asia, Australia, and New Zealand, the native and previously introduced ranges, this tick is a vector of an important pathogen of cattle, Theileria orientalis. In 2017, the pathogenic Ikeda genotype of T. orientalis was associated with cattle mortalities in Virginia and in 2018 the exotic H. longicornis was detected at this same site. To investigate the possible role of this exotic tick in the epidemiology of theileriosis in Virginia, we tested host-seeking H. longicornis for piroplasm infections. We document the detection of exotic Theileria orientalis Ikeda genotype in 12.7 % (15/118) environmentally collected H. longicornis using both the 18S rRNA and major piroplasm surface protein (MPSP) gene targets. This is the first detection of a pathogen in H. longicornis in its introduced range in the United States and offers new insight into the animal health risks associated with the introduction of this exotic tick species to North America.

Molecular detection and genetic characteristics of Babesia gibsoni in dogs in Shaanxi Province, China.

BACKGROUND: Several members of genus Babesia are important pathogens causing babesiosis in dogs. In China, at least five Babesia species have been described in dogs or ticks. This study sought to determine the prevalence and molecular characteristics of various Babesia spp. in dogs in cities in Shaanxi Province in China, including Xi'an and Hanzhong. METHODS: A total of 371 blood samples were collected from pet dogs presenting to veterinary clinics in the cities of Xi'an and Hanzhong in Shaanxi, China. Babesia spp. DNA was detected via amplification of partial 18S rRNA genes by semi-nested PCR. Almost full-length 18S rRNA, ITS, partial TRAP and complete cytb genes were recovered for analysis of the genetic characteristics and relationships with known isolates. RESULTS: A single species, Babesia gibsoni, was identified in dogs in Xi'an and Hanzhong. Consistently, B. gibsoni was also detected in 14 ticks collected from positive dogs. Sequence similarities and phylogenetic analysis suggested that the isolates identified herein showed a closer genetic relationship with isolates from East Asian countries rather than India, Bangladesh, or the USA. Sequence analysis based on tandem repeat analysis of the TRAP gene further revealed that specific haplotypes were circulating in both Xi'an and Hanzhong, with no specific regionality. In addition, 10.9% of all isolates with atovaquone (ATV)-resistance were identified because of M121I mutation in the deduced cytb protein. CONCLUSIONS: This study revealed a high prevalence rate of Babesia infection. Babesia gibsoni was the only Babesia species identified in cases of canine babesiosis in the cities of Xi'an and Hanzhong cities in Shaanxi, China. In addition, the TRAP gene presented high genetic diversity across isolates. Such information is useful for elucidating the epidemiological characteristics of canine babesiosis, as well as the overall genetic diversity of Babesia spp. circulating in dog populations in Shaanxi Province.

Cercopithifilaria species in dogs and ticks from Greece.

Filarioids of the genus Cercopithifilaria (Spirurida, Onchocercidae) are parasites of wild and domestic animals in tropical and subtropical regions being transmitted by ixodid ticks. Though this filarioid species have been studied in canine and tick populations in Europe, data on their species diversity and geographical distribution in Greece is scant. Thus, the aims of this study were to investigate the presence of Cercopithifilaria spp. in dogs and ticks across Greece and to assess the possible risk factors. A total of 500 skin biopsies were collected from dogs, while 508 ticks were collected from 180 infested animals and examined. Sediments from skin biopsies were microscopically screened for detection of dermal microfilaria (mfs). Skin samples (n = 115) and tick specimens (n = 153) were molecularly subjected by PCR. Overall, 70 samples (14%) scored positive for mfs. Specifically, 68 samples (13.6%) were positive for Cercopithifilaria bainae and two (0.4%) were co-infected with C. bainae and Cercopithifilaria sp. II. Molecular analyses revealed that all sequences obtained belong to C. bainae. Haplotype I was the most frequent (92.6%), followed by haplotype XVIII (3%) and haplotypes II and IX (1.5%). Three new haplotypes of C. bainae, named XIX, XX, and XXI, were also identified. Among the risk factors examined, habitat, dog use, body weight, tick infestation history, and the use of acaricides were associated with the presence of C. bainae. The estimated prevalence of Cercopithifilaria spp. demonstrates that these filarioids are common in dogs and ticks in Greece. Finally, the identification of 7 haplotypes for C. bainae confirms their genetic variability.

Molecular evidence of Babesia caballi and Theileria equi in equines and ticks in Nigeria: prevalence and risk factors analysis.

Babesia caballi and Theileria equi are biological agents responsible for equine piroplasmosis (EP). We conducted a robust and extensive epidemiological study in Nigeria on the prevalence and risk factors of EP. Blood (468, both horses and donkeys) and ticks (201 pools) were screened using polymerase chain reaction (PCR). DNA of equine piroplasms was observed in tick pools with B. caballi amplified in Rhipicephalus evertsi evertsi only [minimum infection rate (MIR) of 7.6%] while T. equi was observed in R. e. evertsi (MIR, 61.6%), Hyalomma dromedarii (MIR, 23.7%) and H. truncatum (MIR, 50.0%). Overall results showed that 196/468 (41.9%) animals were positive for equine piroplasms (both B. caballi and T. equi). The prevalence for T. equi was 189/468 (40.4%) compared to 7/468 (1.5%) for B. caballi. In the horses and donkeys, respectively, the prevalence for T. equi was (39.9%; 112/281) and (41.2%; 77/187) compared with (1.4%; 4/281) and (1.6%; 3/187) due to B. caballi. Our analysis showed that location (Jigawa state), Talon breed, horses used for work and reproduction, unsatisfactory husbandry practices, contact with other mammals are risk factors that associated positivity to T. equi infection in horses, whilst horses kept on intensive management appeared to be less prone to infection. On the other hand, Jangora breed of donkeys and location (Jigawa state) are risk factors to infection with T. equi in donkeys. Findings suggest the persistence of EP in equids and ticks in Nigeria.

Ectoparasites of red foxes (Vulpes vulpes) with a particular focus on ticks in subcutaneous tissues.

In the present study, we identified the ectoparasite communities of red foxes in three regions of Poland that encompassed two endemic regions for the occurrence of Dermacentor reticulatus, as well as a region that is free of this tick species ('gap' area). Our study sites were selected to enable the role of foxes as hosts for juvenile (nest dwelling) and adult (exophilic) D. reticulatus ticks to be determined, and to assess their contribution to the spread of this important vector of Babesia canis. We compared also ectoparasite communities between adult foxes with those of fox cubs. Finally, we carried out a systematic search for subcutaneous ticks determining their prevalence and abundance. In 2016-2018, 366 adult foxes and 25 live-trapped cubs were examined for ectoparasites. Ectoparasites were identified based on morphological features, PCR amplification and sequencing. The total prevalence of ectoparasites was higher in cubs (68%) than in adults (62.8%). In adults, 15 parasite species were recorded, including four tick species, seven flea species, scabies, and one Anopluran species each in the genera Felicola and Lipoptena. In cubs, six ectoparasite species were found, including Ixodes kaiseri, a species not found in adults. Although Ixodes ricinus and D. reticulatus were the dominant tick species on adult foxes, no D. reticulatus ticks were found on cubs. Subcutaneous ticks were common (38%) and abundant in all areas. Molecular analysis of subcutaneous nodules allowed the identification of 17 I. ricinus and five D. reticulatus. In conclusion, red foxes play a minor role as hosts of D. reticulatus.

Climate change implications for the distribution of the babesiosis and anaplasmosis tick vector, Rhipicephalus (Boophilus) microplus.

Climate change ranks among the most important issues globally, affecting geographic distributions of vectors and pathogens, and inducing losses in livestock production among many other damaging effects. We characterized the potential geographic distribution of the ticks Rhipicephalus (Boophilus) microplus, an important vector of babesiosis and anaplasmosis globally. We evaluated potential geographic shifts in suitability patterns for this species in two periods (2050 and 2070) and under two emissions scenarios (RCPs 4.5 and 8.5). Our results anticipate increases in suitability worldwide, particularly in the highest production areas for cattle. The Indo-Malayan region resulted in the highest cattle exposure under both climate change projections (2050), with increases in suitability of > 30%. This study illustrates how ecological niche modeling can be used to explore probable effects of climate change on disease vectors, and the possible consequences on economic dimensions.

Molecular detection and characterization of tick-borne haemoparasites among cattle on Zanzibar Island, Tanzania.

Tick-borne diseases (TBDs) are serious constraints to livestock production in Tanzania and other tropical and subtropical countries and impact the livelihoods of resource-poor farming communities in the region. In Tanzania, detailed studies on tick-borne pathogens (TBPs) in cattle using sensitive molecular detection methods are scarce. The objective of this study was to investigate the occurrence and species composition of bovine TBPs in cattle kept in Zanzibar Island. A total of 236 blood samples were randomly collected in cattle population in June and July 2019. We used polymerase chain reaction (PCR) and gene sequencing to detect and identify pathogens. PCR screening of all 236 samples revealed that 64.5% of animals were infected by TBPs, including Theileria parva (34.3%), T. mutans (38.1%), T. taurotragi (30.9%), Anaplasma marginale (10.2%), Babesia bigemina (5.1%), T. velifera (3.4%) and B. bovis (2.1%). Overall a total of 86 animals (36.4%) were co-infected with up to five pathogens including T. parva, T. mutans, T. taurotragi, A. marginale and B. bigemina. The pathogens mostly involved in the co-infection were T. parva, T. taurotragi and T. mutans. Sequence analysis indicated that T. parva p104 and B. bigemina RAP1a genes are diverse among the sampled animals in Zanzibar Island, with 99.64%-100% and 99.51%-100% nucleotide sequence identity value respectively. In contrast, the A. marginale MSP-5, T. mutans 18S rRNA V4 region and B. bovis SBP-2 genes are conserved, with 100%, 99.05%-100% and 99.66%-100% nucleotide sequence identity values respectively. The phylogenetic analyses revealed that T. parva p104 and B. bigemina RAP1a gene sequences showed significant differences of genotypes, as they appear in different clades. Meanwhile, A. marginale MSP-5, T. mutans 18S rRNA V4 region and B. bovis SBP-2 gene sequences appear in the same clade with other sequences extracted from the NCBI GenBank. The epidemiological findings revealed in this study will provide important information on tick-borne diseases in Tanzania and will be used as scientific basis for planning future control strategies.