Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.149
Filtrar
1.
PLoS Negl Trop Dis ; 16(11): e0010846, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36395110

RESUMO

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.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Ixodidae , Carrapatos , Animais , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Febre Hemorrágica da Crimeia/prevenção & controle , Febre Hemorrágica da Crimeia/epidemiologia , Espanha/epidemiologia
2.
Parasit Vectors ; 15(1): 411, 2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36335395

RESUMO

BACKGROUND: Haemaphysalis flava is a hematophagous ectoparasite that acquires the nutrition needed for development and reproduction by sucking blood and digesting the blood meal. During blood-sucking and blood-meal digestion, the prevention of blood coagulation is important for this tick. Previous studies have shown that heat shock cognate 70 (HSC70) protein has certain anticoagulant activities, but its immunogenicity remains unclear. Also, whether the mutation of individual bases of the TKD-like peptide of HSC70 through the overlap extension method can change its anticoagulant activities and immunogenicity remains to be investigated. METHODS: The gene encoding the HSC70 protein was cloned from a complementary DNA library synthesized from H. flava. The coding gene of the TKD-like peptide of HSC70 was mutated into a TKD peptide coding gene (HSC70TKD) using the overlap extension method. Escherichia coli prokaryotic expression plasmids were constructed to obtain the recombinant proteins of HSC70 (rHSC70) and HSC70TKD (rHSC70TKD). The purified rHSC70 and rHSC70TKD were evaluated at different concentrations for anticoagulant activities using four in vitro clotting assays. Emulsifying recombinant proteins with complete and incomplete Freund's adjuvants were subcutaneously immunized in Sprague Dawley rats. The serum antibody titers and serum concentrations of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) were detected using an indirect enzyme-linked immunosorbent assay to assess the immunogenicity of rHSC70 and rHSC70TKD. RESULTS: The open reading frame of HSC70 was successfully amplified and found to have a length of 1958 bp. The gene encoding the TKD-like peptide of HSC70 was artificially mutated, with the 1373-position adenine (A) of the original sequence mutated into guanine (G), the 1385-position cytosine (C) mutated into G and the 1386-position G mutated into C. rHSC70 and rHSC70TKD that fused with His-tag were obtained using the expression plasmids pET-28a-HSC70 and pET-28a-HSC70TKD, respectively. rHSC70 and rHSC70TKD prolonged the thrombin time (TT) and reduced the fibrinogen (FIB) content in the plasma, but did not affect the prothrombin time (PT) or activated partial thromboplastin time (APTT) when compared to the negative control. Interestingly, the ability of rHSC70TKD to prolong the TT and reduce the FIB content in the plasma was better than that of rHSC70. The specific antibody titers of both rHSC70 and rHSC70TKD in rat serum reached 1:124,000 14 days after the third immunization. The serum concentration of IFN-γ in the rHSC70TKD group was higher than that in the rHSC70 group. The rHSC70 group has the highest serum concentration of IL-4, and the serum concentration of IL-4 in the rHSC70TKD group was higher than that in the negative group. CONCLUSIONS: rHSC70 and rHSC70TKD exhibited anticoagulant activities by prolonging the TT and reducing the FIB content in vitro. rHSC70TKD had better anticoagulant activities than rHSC70. Both rHSC70 and rHSC70TKD had good immunogenicity and induced humoral and cellular immunity.


Assuntos
Interleucina-4 , Ixodidae , Animais , Ratos , Anticoagulantes/farmacologia , Anticoagulantes/metabolismo , Escherichia coli/metabolismo , Resposta ao Choque Térmico , Proteínas de Choque Térmico HSC70/genética , Proteínas de Choque Térmico HSC70/metabolismo , Ixodidae/genética , Ratos Sprague-Dawley , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
3.
Genes (Basel) ; 13(11)2022 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-36360286

RESUMO

Ticks rank second in the world as vectors of disease. Tick infestation is one of the factors threatening the health and survival of giant pandas. Here, we describe the mitogenomes of Ixodes acutitarsus and Ixodes ovatus parasitizing giant pandas, and perform comparative and phylogenetic genomic analyses on the newly sequenced and other available mitogenomes of hard ticks. All six newly determined mitogenomes contain a typical gene component and share an ancient Arthropoda gene arrangement pattern. Our study suggests that I. ovatus is a species complex with high genetic divergence, indicating that different clades of I. ovatus represent distinct species. Comparative mitogenomic analyses show that the average A + T content of Ixodidae mitogenomes is 78.08%, their GC-skews are strongly negative, while AT-skews fluctuate around 0. A large number of microsatellites are detected in Ixodidae mitogenomes, and the main microsatellite motifs are mononucleotide A and trinucleotide AAT. We summarize five gene arrangement types, and identify the trnY-COX1-trnS1-COX2-trnK-ATP8-ATP6-COX3-trnG fragment is the most conserved region, whereas the region near the control region is the rearrangement hotspot in Ixodidae mitogenomes. The phylogenetic trees based on 15 genes provide a very convincing relationship (Ixodes + (Robertsicus + ((Bothriocroton + Haemaphysalis) + (Amblyomma + (Dermacentor + (Rhipicentor + (Hyalomma + Rhipicephalus))))))) with very strong supports. Remarkably, Archaeocroton sphenodonti is embedded in the Haemaphysalis clade with strong supports, resulting in paraphyly of the Haemaphysalis genus, so in-depth morphological and molecular studies are essential to determine the taxonomic status of A. sphenodonti and its closely related species. Our results provide new insights into the molecular phylogeny and evolution of hard ticks, as well as basic data for population genetics assessment and efficient surveillance and control for the giant panda-infesting ticks.


Assuntos
Genoma Mitocondrial , Ixodes , Ixodidae , Ursidae , Animais , Ixodidae/genética , Filogenia , Ixodes/genética , Genoma Mitocondrial/genética
4.
PLoS One ; 17(11): e0269150, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36346809

RESUMO

Repellents serve an important role in bite protection. Tick repellents largely rely on biomechanisms that induce responses with direct contact, but synthetic pyrethroids used as spatial repellents against insects have received recent attention for potential use in tick protection systems. An in vitro vertical climb assay was designed to assess spatial repellency against Dermacentor variabilis, Amblyomma americanum, and Ixodes scapularis adult, female ticks. Climbing behavior was assessed with and without the presence of two spatial repellents, transfluthrin and metofluthrin. Repellency parameters were defined to simulate the natural questing behavior of ambushing ticks, including measures of detachment, pseudo-questing duration, climbing deterrence, and activity. Significant effects were observed within each parameter. D. variabilis showed the greatest general susceptibility to each repellent, followed by A. americanum, and I. scapularis. The most important and integrative measure of repellency was climbing deterrence-a measure of the spatial repellent's ability to disrupt a tick's natural propensity to climb. Transfluthrin deterred 75% of D. variabilis, 67% of A. americanum, and 50% of I. scapularis. Metofluthrin was slightly more effective, deterring 81% of D. variabilis, 73% of A. americanum, and 72% of I. scapularis. The present study poses a novel paradigm for repellency and reports a preliminary assessment of spatial repellent effect on tick behavior. Further research will assess spatial repellency in a more natural setting, scale exposure conditions, and incorporate host cues.


Assuntos
Dermacentor , Repelentes de Insetos , Ixodes , Ixodidae , Animais , Feminino , Amblyomma , Repelentes de Insetos/farmacologia
5.
J Vis Exp ; (188)2022 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-36314816

RESUMO

Rickettsioses are caused by a broad range of obligate intracellular bacteria belonging to the genus Rickettsia that can be transmitted to vertebrate hosts through the bite of infected arthropod vectors. To date, emerging or re-emerging epidemic rickettsioses remain a public health risk due to the difficulty in diagnosis, as diagnostic methods are limited and not standardized or universally accessible. Misdiagnosis resulting from a lack of recognition of the signs and symptoms may result in delayed antibiotic treatment and poor health outcomes. A comprehensive understanding of Rickettsia characteristics would ultimately improve clinical diagnosis, assessment, and treatment with improved control and prevention of the disease. Functional studies of rickettsial genes are crucial for understanding their role in pathogenesis. This paper describes a procedure for the electroporation of the Rickettsia parkeri strain Tate's Hell with the shuttle vector pRAM18dSFA and the selection of transformed R. parkeri in tick cell culture with antibiotics (spectinomycin and streptomycin). A method is also described for the localization of transformed R. parkeri in tick cells using confocal immunofluorescence microscopy, a useful technique for checking transformation in vector cell lines. Similar approaches are also suitable for the transformation of other rickettsiae.


Assuntos
Ixodidae , Infecções por Rickettsia , Rickettsia , Carrapatos , Animais , Humanos , Carrapatos/genética , Rickettsia/genética , Infecções por Rickettsia/microbiologia , Vetores Genéticos/genética , Linhagem Celular , Eletroporação
6.
Acta Parasitol ; 67(4): 1708-1718, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36217073

RESUMO

PURPOSE: This study determined the diversity and distribution of tick species infesting domestic dogs and the life cycle parameters of the dominant dog tick species. METHODS: An island-wide, cross-sectional survey of tick species infesting domestic dogs was carried out, and the life cycle of the most commonly occurring dog tick, Rhipicephalus sanguineus was studied under laboratory conditions. RESULTS: A total of 3026 ticks were collected from 1219 dogs in all 25 districts. Eight species in five genera were identified: R. sanguineus (63.4%), R. haemaphysaloides (22.0%), Haemaphysalis bispinosa (12.5%), Haemaphysalis intermedia (0.9%), Haemaphysalis turturis (0.6%), Amblyomma integrum (0.4%), Dermacentor auratus (0.2%) and Hyalomma sp (0.1%). R. sanguineus was the dominant species in the Dry and Wet zones, while R. haemaphysaloides was the dominant species in the Intermediate Zone. Species diversity (Shannon diversity index H) was 1.135, 1.021and 0.849 in the Intermediate, Dry and Wet zones, respectively. The three-host life cycle of R. sanguineus was completed within 70-126 days, and all three stages successfully fed on New Zealand white rabbits under laboratory conditions. The Reproductive Efficiency Index (REI) and Reproductive Fitness Index (RFI) were 50.8 ± 9.69 and 9.1 ± 5.01, respectively. Larger females had higher reproductive success. CONCLUSIONS: Of the eight species infesting domestic dogs in Sri Lanka, R. sanguineaus was the most frequently occurring tick species. The three-host life cycle of R. sanguineus was successfully completed within an average of 98 days on New Zealand white rabbits. The number of eggs laid, duration of the pre-oviposition period, incubation period and parasitic periods of all three life stages were lower than in previous records.


Assuntos
Doenças do Cão , Ixodidae , Rhipicephalus sanguineus , Infestações por Carrapato , Cães , Feminino , Animais , Coelhos , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária , Infestações por Carrapato/parasitologia , Sri Lanka/epidemiologia , Estudos Transversais , Estágios do Ciclo de Vida , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia
7.
J Vector Ecol ; 47(2): 188-194, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36314673

RESUMO

The movement of Ixodes pacificus and Dermacentor occidentalis adult ticks down a hill slope under natural conditions was investigated using the mark-release-recapture (MRR) method. We evaluated the movement of host-seeking adult ticks down a hill slope to determine if ticks travel downhill from an uphill area to trail margins below. During the tick seasons in 2016-2018, the ticks were collected by flagging, marked with paint, released at a predetermined location, and recaptured by weekly flagging. Of the 188 female and 114 male I. pacificus marked and released 30 m above the trail in 2016, 11 (5.8%) females and one (0.9%) male were recaptured at the trail. In 2017, of the 71 female and 52 male I. pacificus, none were recaptured. In 2018, nine (3.6%) female and one (0.4%) male I. pacificus were recaptured of the 247 female and 287 males marked and released. Fifteen (18.5%) female and six (7.3%) male D. occidentalis were recaptured of the 81 females and 82 males marked and released in 2017. The trail deterred further movement with only 0.6% of I. pacificus and 8.3% of D. occidentalis recaptured on the opposite side of the trail. This study demonstrated that some I. pacificus and D. occidentalis adults found along the uphill side of trails may have originated from an area 30 m from the trail margin, some travelling at a rate of 1.6-1.9 m/day under natural conditions in chaparral.


Assuntos
Dermacentor , Ixodes , Ixodidae , Masculino , Feminino , Animais , Estações do Ano , California
8.
Parasit Vectors ; 15(1): 368, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36242057

RESUMO

BACKGROUND: The protein ferritin, which plays an important role in the maintenance of iron homeostasis, is indispensable for iron detoxification, resistance to oxidative stress and innate immunity. Ticks, which are obligate blood-sucking ectoparasites, have to deal with a large amount of iron when they take a blood meal. METHODS: Sequence analysis was undertaken using bioinformatics. A recombinant (r) expression vector, rferritin, was constructed for a prokaryotic expression system. A quantitative polymerase chain reaction platform was used to detect the spatial and temporal expression patterns of target genes and their responses to a low temperature environment. Knockdown of the ferritin genes through RNA interference was used to analyze their effects on physiological parameters of ticks. RESULTS: Two ferritin genes, HrFer1 and HrFer2, were cloned from the tick Hyalomma rufipes. Their open reading frames are 519 base pairs (bp) and 573 bp in length, and number of coding amino acids 170 and 190, respectively. The phylogenetic tree showed that HrFer1 and HrFer2 have a close evolutionary relationship with the H subunit of ferritin. In vitro experiments showed that rHrFer1 and rHrFer2 had concentration-dependent iron chelating activity. The relative expression of the two ferritin genes was higher in the ovary and midgut of H. rufipes. RNA interference results demonstrated that HrFer1 and HrFer2 expression had a significant effect on engorged body weight, number of eggs laid, and mortality of H. rufipes, and that HrFer2 also had a significant effect on feeding duration. Furthermore, the relative expression of ferritin decreased significantly in a low temperature environment, suggesting that HrFer1 and HrFer2 play a regulatory role in the cold stress response of H. rufipes. CONCLUSIONS: The results of the present study improve our understanding of the involvement of ferritins in tick blood-feeding.


Assuntos
Ixodidae , Carrapatos , Aminoácidos/genética , Animais , Feminino , Ferritinas/genética , Ferro/metabolismo , Quelantes de Ferro , Ixodidae/fisiologia , Filogenia , Carrapatos/fisiologia
9.
Emerg Microbes Infect ; 11(1): 2632-2635, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36214427

RESUMO

We identified relapsing fever (RF) Borrelia in 1.45% (145/10426) of the ticks and 1.40% (40/2850) of the wild mammals in a field investigation in China. Three RF Borrelia species, including human-pathogenic Borrelia miyamotoi, Borrelia persica and unclassified Babesia sp. were determined. Main species determined from ticks was B. miyamotoi (44.14%), followed by the unclassified Borrelia sp. (42.76%), and Borrelia theileri (13.10%). In wild mammals, main species found was B. persica (57.50%), followed by the unclassified Borrelia sp. (40.00%), and B. miyamotoi (2.50%). We determined B. theileri and B. persica in China for the first time. The coexistence of RF Borrelia species in one tick species in a given region was observed, with the most frequent coexistence seen for B. miyamotoi and the unclassified Borrelia sp. in Dermacentor silvarum, Haemaphysalis japonica, Haemaphysalis longicornis, and Ixodes persulcatuss respectively. The wide distribution and high variety of RF Borrelia in China pose a potential threat to public health.


Assuntos
Borrelia , Ixodes , Ixodidae , Febre Recorrente , Animais , Humanos , Febre Recorrente/diagnóstico , Febre Recorrente/epidemiologia , Febre Recorrente/veterinária , Borrelia/genética , China/epidemiologia , Mamíferos
10.
Exp Appl Acarol ; 88(1): 127-138, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36282440

RESUMO

This study was initiated to assess the seasonality and to investigate the morphology of questing ixodid ticks in an urban habitat in Central Europe, Hungary. A neglected part of a large cemetery, with sparse tree covering and dense lower vegetation, was sampled monthly from February 2019 to May 2021. All ticks were analyzed morphologically, and selected specimens by amplifying and sequencing two genetic markers. During the study 3818 ticks were collected, including Ixodes ricinus (n = 2772), Ixodes frontalis (n = 350) and Haemaphysalis concinna (n = 696). Ixodes ricinus adults and nymphs showed year-round activity, whereas H. concinna was not active during winter months and early spring. Most I. frontalis nymphs were collected in late winter and early spring, whereas the peak activity of larvae was during late autumn. Interestingly, during the spring, the peak activity of I. ricinus adults and nymphs was later (in May) when preceded by a warm winter in 2020. In contrast, the 2019 and 2021 spring activity peaks occurred in March and April after sharply rising temperatures in February. This shift in the peak activity of I. ricinus coincided with the initiation of questing activity of H. concinna. Three notably different morphotypes and four malformed specimens of I. ricinus were found. However, these were not significantly different in their mitochondrial haplotypes and phylogenetic clustering from typical specimens of this species. On the other hand, I. frontalis was represented by two remarkably different haplogroups, between which in the nymph stage there were no recognizable morphological differences, suggesting the status of these as cryptic species.


Assuntos
Ixodes , Ixodidae , Animais , Filogenia , Ninfa , Ecossistema
11.
Exp Appl Acarol ; 88(2): 225-241, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36309608

RESUMO

The present study reports anomalies in Hyalomma dromedarii and Hyalomma rufipes adults collected from dromedary camels (Camelus dromedarius) in Aswan, Egypt, between January and June 2022. A total of 52 adult ticks displayed one or several local and/or general anomalies. A wide variety of local anomalies was observed including atrophy of one or multiple legs, ectromely, absence of accessory adanal and subanal plates, fusion of adanal and accessory plates, and presence of sclerotized formation in the ventral plate, as well as abnormalities of the spiracle, anal groove, festoon, parma, and posteromedian groove. General anomalies comprised of asymmetries and gynandromorphism. Local anomalies were documented among H. dromedarii and H. rufipes, whereas general anomalies were documented only from H. dromedarii. The present work represents the first report of deuterogynander intrigue gynandromorphism in H. dromedarii, as well as the first report of morphological abnormalities in H. dromedarii and H. rufipes from Egypt.


Assuntos
Ixodidae , Infestações por Carrapato , Carrapatos , Animais , Camelus , Egito , Infestações por Carrapato/veterinária
12.
Arch Microbiol ; 204(11): 677, 2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36282427

RESUMO

Rhipicephalus microplus tick is the ectoparasite causing the greatest economic losses in the livestock industry. Multi-resistance in ticks is increasing, generating the inefficiency of traditional ixodicides, for which biological control has been proposed as an alternative. In this work, we analyze the histomorphological damage caused by the bacterial strain EC-35 on Rhipicephalus microplus. The ixodicidal effect of EC-35 total protein was evaluated on larval or adult ticks comparing with the commercial ixodicide coumaphos 0.02% as a control. Female ticks were processed using the paraffin-embedding technique and stained with hematoxylin-eosin. Also, the pathogenicity of EC-35 was evaluated by capillary feeding and coelom inoculation tests. The identification of the bacterium was performed using the molecular markers 16S RNA and rpoB, by PCR and sequencing technique, and the evolutionary distance was analyzed by Bayesian phylogenetic inference. No differences were observed in the perimeter and area of larvae treated with EC-35 or Coumaphos. The thickness of the integument decreased a 65% with the EC-35 treatment (6.01 ± 0.6 µm) and of 30% in coumaphos (12.04 ± 1.2 µm) in larvae compared with the control group (18.41 ± 2 µm), while no difference was found in adult ticks. The capillary feeding test and coelom inoculation with EC-35 showed an inhibition of reproductive potential of 99.8 ± 7 and an oviposition Inhibition 97 ± 3.02%. The EC-35 strain was genetically related to Serratia marcescens, concluding that these bacteria caused high mortality, oviposition Inhibition, and integument thinning and drastic loss of histoarchitecture in R. microplus tick larvae.


Assuntos
Ixodidae , Rhipicephalus , Animais , Feminino , Rhipicephalus/genética , Serratia marcescens/genética , Ixodidae/genética , Filogenia , Cumafos/farmacologia , Amarelo de Eosina-(YS)/farmacologia , Hematoxilina/farmacologia , Teorema de Bayes , Larva , RNA
13.
Parasit Vectors ; 15(1): 378, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36261834

RESUMO

BACKGROUND: Hard ticks (Ixodidae) are hematophagous ectoparasites that transmit various pathogens to a variety of hosts including humans. Transhumant herds have been involved in the spread of ticks and associated Rickettsia spp., and studies on this neglected topic have been unexplored in many regions including Pakistan. This study aimed to investigate ticks infesting transhumant herds of sheep (Ovis aries) and goats (Capra hircus) in district Shangla, Khyber Pakhtunkhwa, Pakistan. METHODS: Of the 144 examined animals, 112 hosts (68 sheep and 44 goats) of transhumant herds were infested by 419 ticks of different life stages including nymphs (105; 25%), males (58; 14%) and females (256; 61%). For molecular analyses, DNA was extracted from 64 collected ticks and subjected to PCR for the amplification of tick 16S rDNA and ITS2 partial sequences and for the amplification of rickettsial gltA and ompA gene sequences. RESULTS: All tick specimens were identified as Ixodes kashmiricus based on morphological features. The obtained 16S rDNA and ITS2 sequences showed 95.7% and 95.3% identity, respectively, with Ixodes kazakstani reported from Kyrgyzstan. In the phylogenetic tree, the sequences clustered with members of the Ixodes ricinus species complex, including I. kazakstani and Ixodes apronophorus. Additionally, rickettsial gltA and ompA partial sequences were 99.7% identical to Rickettsia sp. endosymbiont of Ixodes spp. from Panama and Costa Rica and 99.2% with Rickettsia endosymbiont from the USA. Phylogenetically, the rickettsial gltA and ompA partial sequences from I. kashmiricus clustered with various haplotypes of Rickettsia endosymbiont, which were sister cladded to Rickettsia monacensis. CONCLUSIONS: This is the first genetic report of I. kashmiricus and associated Rickettsia sp. Large-scale tick surveillance studies across the country are needed to investigate Ixodes ticks and associated pathogens.


Assuntos
Ixodes , Ixodidae , Rickettsia , Humanos , Masculino , Feminino , Animais , Ovinos/genética , Ixodes/microbiologia , Filogenia , Rickettsia/genética , Ixodidae/microbiologia , Cabras , DNA Ribossômico
14.
Vaccine ; 40(47): 6795-6801, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36244881

RESUMO

The southern cattle fever tick (SCFT) Rhipicephalus (Boophilus) microplus, is considered the most important ectoparasite of livestock in the world because of high financial losses associated with direct feeding and transmission of the hemoparasites Babesia bovis, B. bigemina, and Anaplasma marginale. Unfortunately, SCFT in many parts of the world have evolved resistance to all market-available pesticides thus driving development of new control technologies. Vaccination against ticks using the tick gut protein Bm86 has been shown to be effective against acaricide-resistant ticks. This technique has been successfully implemented in Puerto Rico for the control of acaricide-resistant R. microplus on dairy and beef cattle. Observations from Puerto Rico indicate a potentially positive interaction between anti-tick vaccination when used in conjunction with systemic acaricide treatment. In this project, controlled animal studies were completed directly comparing efficacy of anti-tick vaccination with and without systemic acaricide. Results show that the Bm86 anti-tick vaccine in combination with the macrocyclic lactone, Moxidectin, expressed a synergistic interaction, providing greater and longer efficacy than either treatment alone.


Assuntos
Acaricidas , Anaplasmose , Babesiose , Doenças dos Bovinos , Ixodidae , Rhipicephalus , Infestações por Carrapato , Vacinas , Bovinos , Animais , Acaricidas/metabolismo , Lactonas/metabolismo , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária
15.
Parasit Vectors ; 15(1): 321, 2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36085039

RESUMO

BACKGROUND: Arthropod-borne pathogens and their vectors are present throughout Africa. They have been well studied in livestock of sub-Saharan Africa, but poorly studied in companion animals. Given their socioeconomic importance, the African Small Companion Animal Network (AFSCAN), as part of the WSAVA Foundation, initiated a standardized multi-country surveillance study. METHODS: In six countries (Ghana, Kenya, Nigeria, Tanzania, Uganda, and Namibia) in both rural and urban settings, 160 infested cats were sampled to assess their ectoparasite community (ticks and fleas), as well as the micro-parasite prevalence within those ectoparasites (60 and 118 pools of ticks and fleas, respectively) and blood (276 cats, including 116 non-infested). RESULTS: Almost two thirds of all infested cats originated from Tanzania and Kenya. Despite the large macro-geographical variation, no consistent difference was found in ectoparasite diversity and numbers between East and West Africa. Far more flea-infested than tick-infested cats were found. The most dominant ectoparasite was Ctenocephalides felis. Among the ticks, the exophilic Haemaphysalis spp. were the commonest, including species that are not typically linked with companion animals (Haemaphysalis spinulosa and Haemaphysalis elliptica). The most prevalent pathogens found in the blood and fleas were Bartonella henselae and Mycoplasma haemofelis. In the ticks, the dog-associated Hepatozoon canis was most commonly found. A high degree of co-parasitism was found in all countries and habitats. CONCLUSIONS: Our continent-wide standardized field study highlights the cat's potential to serve as a reservoir of pathogens that can be transmitted to humans or livestock, especially when cats are expected to become more commonly kept in African villages and towns.


Assuntos
Infestações por Pulgas , Ixodidae , Sifonápteros , Carrapatos , Animais , Vetores Artrópodes , Gatos , Cães , Infestações por Pulgas/epidemiologia , Infestações por Pulgas/veterinária , Gana , Humanos , Gado
16.
Vet Parasitol ; 310: 109787, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36054968

RESUMO

This study evaluated the acaricidal activity of thymol and carvacrol on Rhipicephalus microplus populations with different resistance profiles and investigated the synergistic effect of combinations of these monoterpenes with cypermethrin. The adult immersion test (AIT) was used to characterize the susceptibility of tick populations (45 field populations) to synthetic acaricides: deltamethrin, amitraz and chlorfenvinphos. The larval packet test (LPT) was used to determine the LC50 values for thymol (25 tick populations) and carvacrol (20 tick populations). The susceptible strain Porto Alegre (POA) was used as a reference for calculating the resistance ratio (RR). Subsequently, larval immersion tests (LIT) were performed with combinations of cypermethrin with thymol or carvacrol to assess a synergistic effect. In the AIT, deltamethrin showed efficacy > 90% in one (2.2%) population tested (mean: 12.1 and 11.1 for populations 1-25 and 26-40, respectively), whereas amitraz and chlorfenvinphos showed efficacy > 90% for two (4.4%) populations (mean: 61.3 and 47.3 for populations 1-25 and 26-40, respectively) and eight (17.7%) populations (mean: 69.7 and 59.7 for populations 1-25 and 26-40, respectively). In the LPT, the LC50 values for thymol and carvacrol varied from 0.67 to 2.12 mg/mL and 0.55-3.21 mg/mL, with an average LC50 for populations of 1.49 and 1.75 mg/mL, respectively. For thymol, no resistance was observed in any of the populations, values of RR50 > 1.5. There was no correlation between the LC50 values for thymol and the efficacy of the chemical acaricides tested. Regarding carvacrol, for only one tick population had the value of RR50 > 1.5, indicating an incipient resistance. No correlation was observed between the LC50 values for carvacrol and the efficacy of tested acaricides. The combination of thymol and carvacrol with cypermethrin showed a synergistic effect in the resistant population (Jaguar - thymol 4.19 and carvacrol 3.67), and no synergistic interaction were showed in the susceptible population. Answering the questions we conclude that: 1 - The comparison between the LC50 values for thymol and carvacrol in field populations and the susceptible strain POA suggests the absence of cross-resistance (ticks and terpenes), and the differences between the LC50 values for thymol and carvacrol in the different R. microplus populations are inherent to the characteristics of each population tested; 2 - the combination of thymol or carvacrol with cypermethrin showed a synergistic effect with different activity according to the population of ticks.


Assuntos
Acaricidas , Clorfenvinfos , Ixodidae , Rhipicephalus , Acaricidas/química , Acaricidas/farmacologia , Animais , Clorfenvinfos/farmacologia , Cimenos , Larva , Piretrinas , Timol/química , Timol/farmacologia
17.
Zootaxa ; 5173(1): 1-73, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-36095415

RESUMO

Ixodes brevisetosus n. sp. from Papua New Guinea, Ixodes contrarius n. sp. from Costa Rica, Ixodes guglielmonei n. sp. from Argentina and Chile, Ixodes insulae n. sp. from Australia, Ixodes moralesi n. sp. from Guatemala and Panama, Ixodes rio n. sp. from Brazil, Ixodes robbinsi n. sp. from Canada and the United States and Ixodes tinamou n. sp. from Peru (Acari: Ixodidae) are described based on females, nymphs and larvae from various avian hosts (Charadriiformes: Charadriidae; Falconiformes: Falconidae; Galliformes: Cracidae, Odontophoridae, Phasianidae; Passeriformes: Acanthizidae, Cardinalidae, Emberizidae, Fringillidae, Furnariidae, Melanocharitidae, Orthonychidae, Paridae, Passeridae, Petroicidae, Thamnophilidae, Troglodytidae, Turdidae; Strigiformes: Strigidae; Tinamiformes: Tinamidae) and a rodent (Rodentia: Muridae). Females, nymphs and larvae of all new species are similar to those of Ixodes auritulus Neumann, 1904, but can be distinguished by the shape of the scutum and basis capituli, relative length of idiosomal setae, auriculae and internal projection on palpal segment I, degree of development of dorsoapical and mesodorsal spurs on palpal segment I, and measurements and proportions of various structures. Females, nymphs and larvae of I. auritulus s. str. are redescribed based on specimens from passerine birds (Furnariidae, Troglodytidae, Turdidae) in Chile. The subspecies I. auritulus zealandicus Dumbleton, 1961 is elevated to species status, Ixodes zealandicus Dumbleton, 1961. Based on our extensive survey and morphological analyses, we evaluate the actual species richness in the I. auritulus species group and discuss future directions in the systematics of this group of ticks.


Assuntos
Ixodes , Ixodidae , Parasitos , Passeriformes , Aves Canoras , Animais , Feminino , Ixodes/anatomia & histologia , Larva , Ninfa , Roedores
18.
Parasit Vectors ; 15(1): 316, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36071436

RESUMO

BACKGROUND: Mate choice is a fundamental element of sexual selection and has the potential to shape the evolution of traits. Mate choice based on body size has been shown to be a common trait in several arthropod species. In hard ticks, a taxon of medical and veterinary importance, engorgement weight is positively correlated with reproductive output but it is unknown whether adult males show mate choice. Here, we experimentally investigated whether males (i) use chemical cues to choose their mating partner, (ii) consistently choose for the same female individual and (iii) prefer females with highest weight after feeding. METHODS: We used two experimental setups which allowed chemical communication between ticks: (i) a horizontal tube preventing physical contact with the female and (ii) an arena where tactile cues were allowed. In total, we tested 62 different triads in 124 tests (66 tests in the horizontal tube and 58 in the arena) composed of one male that could choose between two engorged females. Specifically, we tested 42 triads in the tube and 46 in the arena; 24 triads were repeatedly tested in the tube while 38 triads were tested in both setups. RESULTS: We found no preference for individual or heavier females in either setup. However, in the horizontal tube setup, males significantly preferred females that were not visited by them in the previous test. CONCLUSIONS: Our results suggest a lack of male mate choice despite heavier females having higher fecundity. However, future studies should take into account that males may recognize the potential mating partners they previously met.


Assuntos
Ixodidae , Reprodução , Animais , Tamanho Corporal , Sinais (Psicologia) , Feminino , Fertilidade , Masculino
19.
J Infect ; 85(6): 683-692, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36152736

RESUMO

BACKGROUND: Crimean-Congo haemorrhagic fever (CCHF) is a widespread tick-borne viral infection, present across Africa and Eurasia, which might pose a cryptic public health problem in Uganda. We aimed to understand the magnitude and distribution of CCHF risk in humans, livestock and ticks across Uganda by synthesising epidemiological (cross-sectional) and ecological (modelling) studies. METHODS: We conducted a cross-sectional study at three urban abattoirs receiving cattle from across Uganda. We sampled humans (n = 478), livestock (n = 419) and ticks (n = 1065) and used commercially-available kits to detect human and livestock CCHF virus (CCHFV) antibodies and antigen in tick pools. We developed boosted regression tree models to evaluate the correlates and geographical distribution of expected tick and wildlife hosts, and of human CCHF exposures, drawing on continent-wide data. FINDINGS: The cross-sectional study found CCHFV IgG/IgM seroprevalence in humans of 10·3% (7·8-13·3), with antibody detection positively associated with reported history of tick bite (age-adjusted odds ratio = 2·09 (1·09-3·98)). Cattle had a seroprevalence of 69·7% (65·1-73·4). Only one Hyalomma tick (CCHFV-negative) was found. However, CCHFV antigen was detected in Rhipicephalus (5·9% of 304 pools) and Amblyomma (2·9% of 34 pools) species. Modelling predicted high human CCHF risk across much of Uganda, low environmental suitability for Hyalomma, and high suitability for Rhipicephalus and Amblyomma. INTERPRETATION: Our epidemiological and ecological studies provide complementary evidence that CCHF exposure risk is widespread across Uganda. We challenge the idea that Hyalomma ticks are consistently the principal reservoir and vector for CCHFV, and postulate that Rhipicephalus might be important for CCHFV transmission in Uganda, due to high frequency of infected ticks and predicted environmental suitability. FUNDING: UCL Global Challenges Research Fund (GCRF) and Pan-African Network on Emerging and Re-Emerging Infections (PANDORA-ID-NET) funded by the European and Developing Countries Clinical Trials Partnership (EDCTP) under the EU Horizon 2020 Framework Programme for Research and Innovation.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Ixodidae , Rhipicephalus , Humanos , Animais , Bovinos , Febre Hemorrágica da Crimeia/epidemiologia , Febre Hemorrágica da Crimeia/diagnóstico , Estudos Transversais , Estudos Soroepidemiológicos , Uganda/epidemiologia
20.
J Vet Med Sci ; 84(11): 1469-1473, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36123016

RESUMO

In this study, Babesia screening was conducted in 55 rodents and 160 tick samples collected from primary forests and an oil palm plantation in Sarawak, Malaysian Borneo. PCR targeting the 18S ribosomal DNA revealed the presence of Babesia spp. DNA detected in two questing male Haemaphysalis shimoga ticks collected from the oil palm plantation. Sequence analysis revealed that both sequences were identical and had 98.6% identity to a Babesia macropus sequence obtained from Eastern grey kangaroos (Macropus giganteus) in Australia. Phylogenetic tree revealed clustering with marsupial-associated Babesia spp. in the Babesia sensu stricto clade. Whether or not H. shimoga is the competent vector and the importance of the Babesia sp. detected in this study warrants more investigation.


Assuntos
Babesia , Ixodidae , Animais , Babesia/genética , Filogenia , Macropodidae , Malásia , Bornéu , RNA Ribossômico 18S/genética , Genótipo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...