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1.
Rev Bras Parasitol Vet ; 30(1): e025220, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33605390

RESUMO

Southern cattle tick resistance to pour-on and injectable acaricides has yet to be evaluated on a broader scope, and the paucity of information on the subject may hinder efforts to control this parasite. The objective of this study was to evaluate the resistance profile of ten populations of Rhipicephalus microplus to the acaricides fluazuron, fipronil and ivermectin in cattle herds in Mato Grosso do Sul, Brazil. The larval immersion test (LIT) was used to evaluate susceptibility to ivermectin and fipronil and the adult immersion test (AIT) was performed to evaluate fluazuron. Samples were randomly obtained in ten farms, and in general, we found resistance in five samples to fluazuron and in four samples to ivermectin and fipronil. Six samples showed incipient resistance to ivermectin and fipronil. Five of the ten evaluated samples showed resistance and/or incipient resistance to all the active ingredients, and the other five to two active ingredients. Among the samples classified as resistant, the average resistance ratio for ivermectin was 2.75 and 3.26 for fipronil. These results demonstrate the advanced status of resistance to the most modern chemical groups for the control of R. microplus in the state of Mato Grosso do Sul.


Assuntos
Acaricidas , Doenças dos Bovinos , Resistência a Medicamentos , Rhipicephalus , Infestações por Carrapato , Acaricidas/farmacologia , Animais , Brasil , Bovinos , Doenças dos Bovinos/parasitologia , Ivermectina/farmacologia , Compostos de Fenilureia/farmacologia , Pirazóis/farmacologia , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária
2.
Parasitol Res ; 120(2): 383-394, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33447885

RESUMO

Ticks are considered the second most important vectors of pathogens worldwide, after mosquitoes. This study provides a systematic review of vector-host relationships between ticks and mammals (domestic and wild) and consolidates information from studies conducted in Colombia between 1911 and 2020. Using the PRISMA method, 71 scientific articles containing records for 51 tick species (Argasidae and Ixodidae) associated with mammals are reported. The existing information on tick-mammal associations in Colombia is scarce, fragmented, or very old. Moreover, 213 specimens were assessed based on morphological and molecular analyses, which allowed confirming eight tick species associated with mammals: Amblyomma calcaratum, Amblyomma dissimile, Amblyomma mixtum, Amblyomma nodosum, Amblyomma ovale, Amblyomma varium, Ixodes luciae, and Ixodes tropicalis. Several tick species are molecularly confirmed for Colombia and nine new relationships between ticks and mammals are reported. This research compiles and confirms important records of tick-mammal associations in Colombia.


Assuntos
Vetores Artrópodes/fisiologia , Mamíferos/parasitologia , Infestações por Carrapato/veterinária , Carrapatos/fisiologia , Animais , Argasidae/classificação , Argasidae/genética , Argasidae/fisiologia , Vetores Artrópodes/classificação , Vetores Artrópodes/genética , Colômbia , Interações Hospedeiro-Parasita , Ixodidae/classificação , Ixodidae/genética , Ixodidae/fisiologia , Infestações por Carrapato/parasitologia , Carrapatos/classificação , Carrapatos/genética
3.
PLoS One ; 15(9): e0239029, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941509

RESUMO

In studies assessing tick abundance, the use of live traps to capture and euthanize rodent hosts is a commonly used method to determine their burden. However, captive animals can experience debilitating or fatal capture stress as a result prior to collection. An alternative method is the use of lethal traps, but this can potentially lead to tick drop-off between the time of capture and collection. In this study, in order to determine whether subjecting animals to capture stress is inevitable, we tested the difference in sheep tick (Ixodes ricinus) larval burdens between bank voles (Myodes glareolus) captured alive and euthanized, and lethally trapped bank voles. During 2017 and 2018, 1318 bank voles were captured using live (Ugglan Special no. 2) and lethal (Rapp2 Mousetrap) traps during two consecutive years over three seasons in two locations in Norway. Voles captured alive would remain captive until euthanized, while lethally trapped voles were killed instantly upon capture. Log-linear models, accounting for overdispersion, were used to determine whether trap type was influencing observed tick burden. Bank voles captured in lethal traps carried 5.7% more larvae compared to euthanized voles captured in live traps, but this difference was not significant (p = 0.420). Males were overall captured 2.7 times more frequently than females, and the sex ratio was equal in both trap types. This study shows that the use of lethal traps to determine tick burden of rodents is sufficiently reliable, without having to subject animals to potentially lethal stress, hereby reducing some ethical concerns of animal suffering and the results thereof, without compromising accuracy. Lethal trapping is also often more economical and practical, further favoring this collection method.


Assuntos
Arvicolinae/parasitologia , Monitoramento Epidemiológico/veterinária , Infestações por Carrapato/epidemiologia , Animais , Feminino , Ixodes/patogenicidade , Larva , Masculino , Noruega , Infestações por Carrapato/veterinária , Carrapatos/patogenicidade
4.
Exp Appl Acarol ; 82(2): 281-294, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32886258

RESUMO

The efficacy of Allium sativum and Cannabis sativa against Rhipicephalus microplus ticks was evaluated using the adult immersion and the larval packet test. In addition, an in silico approach was utilized by performing a docking study in order to identify the active ingredients from both plants. Results showed a comparatively high lethal effect of A. sativum and C. sativa on egg laying (index of egg laying = 0.26 and 0.24, respectively), egg hatching (33.5 and 37.1, respectively), and total larval mortality (100%, both), at 40 mg/mL. When applied to cattle which had been inoculated with larvae ticks, it was observed that a 45% solution of both herbal extracts significantly reduced the number of ticks by 96 h post treatment. We analyzed in silico 27 known active molecules from both plants and identified in the PubChem database to explore the hypothesis that the effect found on ticks was based on inhibition of acetylcholinesterase (AChE). Vitamin E and cannabidiol are the most potent AChE inhibitors with docking scores of -15.85 and -14.38, respectively. Based on these findings, we conclude that A. sativum and C. sativa may potentially be used for the control of R. microplus, and should be further investigated as a potential supplement to or replacement of synthetic acaricides.


Assuntos
Acaricidas , Cannabis/química , Doenças dos Bovinos/prevenção & controle , Alho/química , Extratos Vegetais/farmacologia , Rhipicephalus , Infestações por Carrapato/veterinária , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Larva , Infestações por Carrapato/prevenção & controle
5.
PLoS One ; 15(8): e0228366, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866142

RESUMO

The role of questing ticks in the epidemiology of tick-borne diseases in Kenya's Maasai Mara National Reserve (MMNR), an ecosystem with intensified human-wildlife-livestock interactions, remains poorly understood. We surveyed the diversity of questing ticks, their blood-meal hosts, and tick-borne pathogens to understand potential effects on human and livestock health. By flagging and hand-picking from vegetation in 25 localities, we collected 1,465 host-seeking ticks, mostly Rhipicephalus and Amblyomma species identified by morphology and molecular analysis. We used PCR with high-resolution melting (HRM) analysis and sequencing to identify Anaplasma, Babesia, Coxiella, Ehrlichia, Rickettsia, and Theileria pathogens and blood-meal remnants in 231 tick pools. We detected blood-meals from humans, wildebeest, and African buffalo in Rh. appendiculatus, goat in Rh. evertsi, sheep in Am. gemma, and cattle in Am. variegatum. Rickettsia africae was detected in Am. gemma (MIR = 3.10) that had fed on sheep and in Am. variegatum (MIR = 250) that had fed on cattle. We found Rickettsia spp. in Am. gemma (MIR = 9.29) and Rh. evertsi (MIR = 200), Anaplasma ovis in Rh. appendiculatus (MIR = 0.89) and Rh. evertsi (MIR = 200), Anaplasma bovis in Rh. appendiculatus (MIR = 0.89), and Theileria parva in Rh. appendiculatus (MIR = 24). No Babesia, Ehrlichia, or Coxiella pathogens were detected. Unexpectedly, species-specific Coxiella sp. endosymbionts were detected in all tick genera (174/231 pools), which may affect tick physiology and vector competence. These findings show that ticks from the MMNR are infected with zoonotic R. africae and unclassified Rickettsia spp., demonstrating risk of African tick-bite fever and other spotted-fever group rickettsioses to locals and visitors. The protozoan pathogens identified may also pose risk to livestock production. The diverse vertebrate blood-meals of questing ticks in this ecosystem including humans, wildlife, and domestic animals, may amplify transmission of tick-borne zoonoses and livestock diseases.


Assuntos
Infestações por Carrapato/epidemiologia , Doenças Transmitidas por Carrapatos/epidemiologia , Carrapatos/patogenicidade , Animais , Animais Selvagens , Babesia , Bovinos , Doenças dos Bovinos/microbiologia , Coxiella , Ecossistema , Ehrlichia , Humanos , Ixodidae/microbiologia , Quênia/epidemiologia , Rhipicephalus , Rickettsia , Ovinos , Theileria , Infestações por Carrapato/veterinária , Doenças Transmitidas por Carrapatos/microbiologia , Carrapatos/parasitologia , Zoonoses
6.
Exp Appl Acarol ; 82(1): 125-135, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32856170

RESUMO

Ticks are among the best studied parasitic groups as they spread important pathogens of medical and veterinary importance worldwide. Migratory birds can play an important role in transporting ticks infected with pathogens across wide geographic regions. It is therefore important to understand which factors promote tick parasitism rates across their avian hosts and the associated potential for disease spread. Here, we identified the host attributes of infestation probability of ticks from the genus Amblyomma in 955 birds from Pantanal, Brazil. Infestation rates exhibited considerable variation across the 129 avian species surveyed and were explained by both host ecological traits and evolutionary history. The probability of an individual bird being infested with immature ticks (larvae and/or nymphs) was higher across resident bird species that forage at ground level and during the wet season. Bird species that feed on vertebrates were less likely to be infested by ticks. Other ecological traits known to promote tick exposure (age, body mass, social behavior, and sex) did not predict infestation probability. Our findings demonstrate that tick occurrence in Pantanal birds is determined by avian host attributes, but tick occurrence throughout the year constrains exposure to host-seeking ticks. Moreover, the ecology of the avian host might prevent the potential spread of tick-borne diseases outside Pantanal as migratory hosts are likely less infested by ticks.


Assuntos
Doenças das Aves , Aves/parasitologia , Estações do Ano , Infestações por Carrapato , Migração Animal , Animais , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Brasil , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária , Carrapatos
7.
PLoS One ; 15(8): e0237191, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776959

RESUMO

The American dog tick, Dermacentor variabilis, is a veterinary- and medically- significant tick species that is known to transmit several diseases to animal and human hosts. The spatial distribution of this species in North America is not well understood, however; and knowledge of likely changes to its future geographic distribution owing to ongoing climate change is needed for proper public health planning and messaging. Two recent studies have evaluated these topics for D. variabilis; however, less-rigorous modeling approaches in those studies may have led to erroneous predictions. We evaluated the present and future distribution of this species using a correlative maximum entropy approach, using publicly available occurrence information. Future potential distributions were predicted under two representative concentration pathway (RCP) scenarios; RCP 4.5 for low-emissions and RCP 8.5 for high-emissions. Our results indicated a broader current distribution of this species in all directions relative to its currently known extent, and dramatic potential for westward and northward expansion of suitable areas under both climate change scenarios. Implications for disease ecology and public health are discussed.


Assuntos
Distribuição Animal/fisiologia , Dermacentor/fisiologia , Doenças do Cão/epidemiologia , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária , Algoritmos , Animais , Mudança Climática , Cães , Ecossistema , Previsões , Humanos , Modelos Estatísticos , América do Norte/epidemiologia , Chuva , Temperatura
8.
Exp Appl Acarol ; 82(1): 161-169, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32809185

RESUMO

Morphological abnormalities in ticks have rarely been reported in nature. The existing knowledge about anomalies in ticks collected in Africa is very sparse. In this paper, we describe abnormalities in Amblyomma, Hyalomma, and Rhipicephalus ticks collected from cattle, sheep, goats, camels, and horses in Kassala and North Kordofan states, Sudan, between January and August 2017. A number of 15 adult ticks displayed one or several local anomalies, such as ectromely, abnormalities of the ventral plates, and body deformities, besides newly described multiple cuticula scars. This study presents the first report of local anomalies in ticks belonging to three genera in Sudan and highlights the need to investigate the association between such morphological abnormalities and tick biology.


Assuntos
Animais Domésticos/parasitologia , Ixodidae/anatomia & histologia , Infestações por Carrapato , Animais , Bovinos , Cavalos , Ovinos , Sudão , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/veterinária
9.
PLoS Pathog ; 16(8): e1008759, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745135

RESUMO

Ticks (order: Ixodida) are a highly diverse and ecologically important group of ectoparasitic blood-feeding organisms. One such species, the seabird tick (Ixodes uriae), is widely distributed around the circumpolar regions of the northern and southern hemispheres. It has been suggested that Ix. uriae spread from the southern to the northern circumpolar region millions of years ago and has remained isolated in these regions ever since. Such a profound biographic subdivision provides a unique opportunity to determine whether viruses associated with ticks exhibit the same evolutionary patterns as their hosts. To test this, we collected Ix. uriae specimens near a Gentoo penguin (Pygoscelis papua) colony at Neko harbour, Antarctica, and from migratory birds-the Razorbill (Alca torda) and the Common murre (Uria aalge)-on Bonden island, northern Sweden. Through meta-transcriptomic next-generation sequencing we identified 16 RNA viruses, seven of which were novel. Notably, we detected the same species, Ronne virus, and two closely related species, Bonden virus and Piguzov virus, in both hemispheres indicating that there have been at least two cross-circumpolar dispersal events. Similarly, we identified viruses discovered previously in other locations several decades ago, including Gadgets Gully virus, Taggert virus and Okhotskiy virus. By identifying the same or closely related viruses in geographically disjunct sampling locations we provide evidence for virus dispersal within and between the circumpolar regions. In marked contrast, our phylogenetic analysis revealed no movement of the Ix. uriae tick hosts between the same locations. Combined, these data suggest that migratory birds are responsible for the movement of viruses at both local and global scales.


Assuntos
Doenças das Aves/epidemiologia , Aves/parasitologia , Interações Hospedeiro-Parasita , Ixodes/fisiologia , Infecções por Vírus de RNA/virologia , Vírus de RNA/classificação , Infestações por Carrapato/veterinária , Animais , Doenças das Aves/parasitologia , Filogenia , Infecções por Vírus de RNA/genética , Vírus de RNA/genética , Vírus de RNA/isolamento & purificação , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/parasitologia
10.
J S Afr Vet Assoc ; 91(0): e1-e6, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32633987

RESUMO

Otobius megnini has been associated with certain clinical conditions in horses in both California and Mexico. A number of cases similar to those described previously have been identified by the author in South Africa. This case report summarises these cases to demonstrate that the clinical condition occurs readily in South Africa and may be increasing in occurrence. The disease has minimal coverage in the literature making it more likely that a veterinarian, unfamiliar with the disease, will miss the diagnosis. The author would like to make veterinarians aware of this as a potential differential diagnosis. This study is a retrospective review of clinical data. Clinical records of patients with similar clinical signs and treatment were reviewed and grouped together as relevant cases for this case report. Ten cases of O. megnini associated neuromuscular dysfunction are reported, suggesting a link between the occurrence of the tick and the clinical condition. Clinical signs include third eyelid prolapse, localised muscle fasciculations, elevated heart rate and limb stamping. Serum chemistry changes commonly show increased aspartate aminotransferase and creatine kinase enzymes activities. The occurrence of the ticks within South Africa and the increasing number of cases presented demonstrate the need for more investigation into the pathophysiology of this condition.


Assuntos
Argasidae/fisiologia , Doenças dos Cavalos/diagnóstico , Infestações por Carrapato/veterinária , Animais , Diagnóstico Diferencial , Feminino , Doenças dos Cavalos/parasitologia , Cavalos , Masculino , Estudos Retrospectivos , África do Sul , Infestações por Carrapato/diagnóstico , Infestações por Carrapato/parasitologia
11.
PLoS One ; 15(7): e0234005, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609768

RESUMO

Rhipicephalus microplus is recognized as a tick species highly prevalent in cattle, with a wide pantropical distribution that seems to continue spreading geographically. However, its role as a biological vector has been scarcely studied in the livestock context. In this study, a 16S rRNA next-generation sequencing analysis was used to determine bacterial diversity in salivary glands and gut of R. microplus from two contrasting livestock agroecosystems in Antioquia, Colombia. Both the culture-independent approach (CI) and the culture-dependent (CD) approach were complementarily adopted in this study. A total of 341 unique OTUs were assigned, the richness showed to be higher in the Northern than in the Middle Magdalena region, and a high diversity was found at the phylum and genus levels in the samples obtained. With the CI approach, Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria were the most common phylum of bacteria regardless of the organ, or geographic origin of the specimens analyzed. While the relative abundance of bacteria at a phylum level with the CD approach varied between analyzed samples, the data obtained suggest that a high diversity of species of bacteria occurs in R. microplus from both livestock agroecosystems. Bacterial genera such as Anaplasma, Coxiella, and Ehrlichia, recognized for their implications in tick-borne diseases, were also detected, together with endosymbionts such as Lysinibacillus, previously reported as a potential tool for biological control. This information is useful to deepen the knowledge about microbial diversity regarding the relations between endosymbionts and pathogens and could facilitate the future development of epidemiological surveillance in livestock systems.


Assuntos
Bactérias/classificação , Rhipicephalus/genética , Rhipicephalus/microbiologia , Animais , Bactérias/genética , Bovinos , Doenças dos Bovinos/microbiologia , Colômbia , Microbioma Gastrointestinal/genética , Gado/genética , RNA Ribossômico 16S/genética , Saliva/química , Infestações por Carrapato/veterinária , Doenças Transmitidas por Carrapatos/epidemiologia
12.
Ann Parasitol ; 66(2): 255-257, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32592549

RESUMO

The aim of this study was to recognise the etiological factor of a disease with symptoms of lameness and cardiac failure, which occurred in one dog 4 weeks after invasion by ticks. A serological examination as well as molecular examination (PCR) was done. In the sample of the serum, the presence of antibodies specific to Borrelia burgdorferi were detected. Antibiotic therapy with doxycycline did not cause significant improvement, so the owners of the dog decided about its euthanasia. During the necroscopy, a dilated heart was recognised. In the heart samples, the genetic material of Borrelia was detected. The results of serological and molecular examinations showed that in the discussed case, an etiological factor of the disease was spirochetes. In light of the research, veterinary practitioners should keep in mind the presence of Lyme disease in dogs in Poland and include it in differential diagnoses for lameness and cardiological problems.


Assuntos
Infecções por Borrelia , Doenças do Cão , Miocardite , Infestações por Carrapato , Animais , Anticorpos Antibacterianos/sangue , Infecções por Borrelia/complicações , Infecções por Borrelia/diagnóstico , Doenças do Cão/diagnóstico , Doenças do Cão/etiologia , Doenças do Cão/microbiologia , Doenças do Cão/parasitologia , Cães , Eutanásia Animal , Coração/parasitologia , Miocardite/diagnóstico , Miocardite/etiologia , Polônia , Infestações por Carrapato/complicações , Infestações por Carrapato/microbiologia , Infestações por Carrapato/veterinária
13.
Parasitol Res ; 119(10): 3523-3529, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32572573

RESUMO

The cattle tick Rhipicephalus microplus has a large impact on cattle production due to its bloodsucking habit and transmission of pathogens that cause babesiosis and anaplasmosis. Application of acaricides constitutes the major control method but is often accompanied by serious drawbacks, including environmental contamination and an increase in acaricide resistance by ticks. The recent development of anti-tick vaccines has provided positive results in the post-genomic era, owing to the rise of reverse vaccinological and bioinformatics approaches to analyze and identify candidate protective antigens for use against ticks. The ATAQ protein is considered a novel antigen for the control of the cattle tick R. microplus; it is expressed in midguts and Malpighian tubules of all ticks from the Rhipicephalus genus. However, genetic diversity studies are required. Here, the ATAQ gene was sequenced of seven R. microplus tick isolates from different regions in Mexico to understand the genetic diversity. The results showed that sequence identity among the Mexican isolates ranged between 98 and 100% and 97.8-100% at the nucleotide and protein levels, respectively. Alignments of deduced amino acid sequences from different R. microplus ATAQ isolates in Mexico revealed a high degree of conservation. However, the Mexican isolates differed from the R. microplus "Mozambique" strain, at 20 amino acid residues. Finally, the analysis of more R. microplus isolates, and possibly of other Rhipicephalus species, to determine the genetic diversity in the ATAQ locus is essential to suggest this antigen as a vaccine candidate that might control tick infestations.


Assuntos
Proteínas de Artrópodes/genética , Doenças dos Bovinos/prevenção & controle , Rhipicephalus/imunologia , Infestações por Carrapato/veterinária , Vacinas/imunologia , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/imunologia , Bovinos , Variação Genética , México , Rhipicephalus/genética , Alinhamento de Sequência , Infestações por Carrapato/prevenção & controle , Vacinas/administração & dosagem
14.
Parasitol Res ; 119(8): 2411-2420, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32533261

RESUMO

In Uganda, the role of ticks in zoonotic disease transmission is not well described, partly, due to limited available information on tick diversity. This study aimed to identify the tick species that infest cattle. Between September and November 2017, ticks (n = 4362) were collected from 5 districts across Uganda (Kasese, Hoima, Gulu, Soroti, and Moroto) and identified morphologically at Uganda Virus Research Institute. Morphological and genetic validation was performed in Germany on representative identified specimens and on all unidentified ticks. Ticks were belonging to 15 species: 8 Rhipicephalus species (Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus microplus, Rhipicephalus decoloratus, Rhipicephalus afranicus, Rhipicephalus pulchellus, Rhipicephalus simus, and Rhipicephalus sanguineus tropical lineage); 5 Amblyomma species (Amblyomma lepidum, Amblyomma variegatum, Amblyomma cohaerens, Amblyomma gemma, and Amblyomma paulopunctatum); and 2 Hyalomma species (Hyalomma rufipes and Hyalomma truncatum). The most common species were R. appendiculatus (51.8%), A. lepidum (21.0%), A. variegatum (14.3%), R. evertsi evertsi (8.2%), and R. decoloratus (2.4%). R. afranicus is a new species recently described in South Africa and we report its presence in Uganda for the first time. The sequences of R. afranicus were 2.4% divergent from those obtained in Southern Africa. We confirm the presence of the invasive R. microplus in two districts (Soroti and Gulu). Species diversity was highest in Moroto district (p = 0.004) and geographical predominance by specific ticks was observed (p = 0.001). The study expands the knowledge on tick fauna in Uganda and demonstrates that multiple tick species with potential to transmit several tick-borne diseases including zoonotic pathogens are infesting cattle.


Assuntos
Doenças dos Bovinos/parasitologia , Ixodidae/classificação , Infestações por Carrapato/veterinária , Animais , Biodiversidade , Bovinos , Ixodidae/anatomia & histologia , Ixodidae/genética , Infestações por Carrapato/parasitologia , Uganda
15.
Exp Parasitol ; 216: 107937, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32535114

RESUMO

The chemical composition and acaricidal activity of plant-derived essential oils was assessed against Rhipicephalus microplus ticks. The essential oils of Mentha arvensis, Cymbopogon citratus and C. nardus were assessed for acaricidal activity against Rhipicephalus microplus. Essential oils (EO) of plants were separated by hydrodistillation (three times) and analyzed using gas chromatography - mass spectrometer (GC-MS). For bioassays, engorged females of R. microplus were exposed to C. citratus and C. nardus EO at 2%, 3%, 4% and 5% concentrations; and to M. arvensis EO at 1%, 3%, and 5% for 5 min. The weight egg mass, nutrient index (N.I), egg production index (E.P.I), hatching and control rate were evaluated. Non-feed larvae of R. microplus were exposed to essential oils with 0.25%, 0.5%; 1%; 1.5% and 2% concentrations; the mortality rate was measured after 48 h. Only engorged females presented reduced biological activities (oviposition, E.P.I) after exposure to M. arvensis at 3%, when in comparison to both positive and negative controls. The hatchability of R. microplus larvae ranged from 66.9% (after exposure to C. nardus EO at 5%) to 99.2% (positive control). The nutrition index was lower (46.6%) for the exposure to M. arvensis EO at 5%. M. arvensis at 3% and 5% concentrations was significantly efficient for engorged females when compared to control (53.7% and 47.5%, respectively). C. citratus EO at 1%, 1.5% and 2% concentrations yielded better results in the larval packet test, causing 100% mortality. Nonetheless, C. nardus and M. arvensis EO at 2% yielded 66% and 39% mortality, respectively. The study showed that M. arvensis presented potential for the control of R. microplus engorged females while C. citratus and C. nardus presented potential as a larvicide.


Assuntos
Acaricidas , Cymbopogon/química , Mentha/química , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Rhipicephalus , Acaricidas/isolamento & purificação , Animais , Bioensaio/veterinária , Bovinos , Doenças dos Bovinos/parasitologia , Destilação/métodos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Dose Letal Mediana , Monoterpenos/isolamento & purificação , Monoterpenos/farmacologia , Óleos Voláteis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Óleos Vegetais/isolamento & purificação , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária
16.
Parasitol Res ; 119(7): 2039-2045, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32377908

RESUMO

Ticks are ectoparasites that feed on blood of a broad taxonomic range of terrestrial and flying vertebrates and are distributed across a wide range of environmental conditions. Here, we explore the biotic and abiotic factors on infestation probability of ticks of the genus Amblyomma and assess the degree of host specificity based on analysis of 1028 birds surveyed across Brazil. We show that tick infestation rates exhibited considerable variation across the 235 avian species analyzed and that the probability of an individual bird being parasitized by immature ticks (larvae and nymphs) increased with annual precipitation. Host phylogeny and two host ecological traits known to promote tick exposure (body mass and foraging behavior) did not predict infestation probability. Moreover, immature ticks displayed a low degree of host specificity at the family level. Lastly, tick occurrence in birds carrying infection with avian malaria and related parasites did not differ from those free of these haemosporidian parasites, indicating a lack of parasite avoidance by immature ticks. Our findings demonstrate that tick occurrence in birds across Brazilian biomes responds to environmental factors rather than ecological and evolutionary host attributes.


Assuntos
Aves/parasitologia , Meio Ambiente , Especificidade de Hospedeiro/fisiologia , Interações Hospedeiro-Parasita/fisiologia , Ixodidae/fisiologia , Infestações por Carrapato/veterinária , Animais , Doenças das Aves/epidemiologia , Doenças das Aves/parasitologia , Brasil/epidemiologia , Larva , Malária Aviária/epidemiologia , Ninfa , Filogenia
17.
PLoS One ; 15(5): e0233567, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437470

RESUMO

An outbreak of Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a major human and animal health concern in Mexicali, Mexico. Due to high rates of brown dog tick infestation, susceptibility, and association with humans, dogs serve as sentinels and have a key role in the ecology of RMSF. A cross-sectional household questionnaire study was conducted in six rural and urban locations to characterize dog ecology and demography in RMSF high-and low-risk areas of Mexicali. In addition, we tracked movement patterns of 16 dogs using a GPS data logger. Of 253 households, 73% owned dogs, and dog ownership tended to be higher in high-risk areas, with a mean dog:human ratio of 0.43, compared with 0.3 in low-risk areas. Dogs in high-risk areas had higher fecundity and roamed more, but the dog density and numbers of free-roaming dogs were comparable. There was a higher proportion of younger dogs and lower proportion of older dogs in high-risk areas. The high proportion of immunologically naïve puppies in high risk areas could result in a lack of herd immunity leading to a more vulnerable dog and human population. The marked increase of space use of free-roaming dogs in high-risk areas suggests that unrestrained dogs could play an important role in spreading ticks and pathogens. As means to limit RMSF risk, practical changes could include increased efforts for spay-neuter and policies encouraging dog restraint to limit canine roaming and spread of ticks across communities; due to dog density is less impactful such policies may be more useful than restrictions on the number of owned dogs.


Assuntos
Doenças do Cão/epidemiologia , Cães/parasitologia , Febre Maculosa das Montanhas Rochosas/veterinária , Infestações por Carrapato/veterinária , Distribuição Animal , Animais , Estudos Transversais , Doenças do Cão/transmissão , Cães/fisiologia , Feminino , Humanos , Masculino , México/epidemiologia , Animais de Estimação/parasitologia , Animais de Estimação/fisiologia , Rhipicephalus sanguineus/fisiologia , Febre Maculosa das Montanhas Rochosas/epidemiologia , Febre Maculosa das Montanhas Rochosas/transmissão , Infestações por Carrapato/epidemiologia , Infestações por Carrapato/transmissão
18.
Rev Bras Parasitol Vet ; 29(2): e016919, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428183

RESUMO

Dogs have been implicated as main reservoirs for visceral leishmaniasis (VL) in urban areas. Therefore, studies on this species provide important data for public health. Thus, the objective of the present study was to ascertain the seroprevalence of canine VL (CVL) and the associated factors in the Brejo Paraibano microregion, northeastern Brazil. A total of 409 dogs were sampled from the eight municipalities of the microregion: Alagoa Grande, Alagoa Nova, Areia, Bananeiras, Borborema, Matinhas, Pilões and Serraria. The diagnosis of CVL was made using an enzyme-linked immunosorbent assay (ELISA S7®), through which the prevalence observed was 29.3%. By robust Poisson regression analysis two factors were associated with seroprevalence: illiterate/incomplete elementary owner's education level (prevalence ratio = 1.57; 95% CI = 1.05-2.34; p-value = 0.027) and tick infestation (prevalence ratio = 1.82; 95% CI = 1.27-2.61; p-value = 0.001). It is concluded that the seroprevalence of CVL in the Brejo Paraibano microregion is high. The factors associated with seroprevalence indicated the importance to develop socioeducational actions on the population, and the finding that tick infestation was associated with seroprevalence shows that there is a need for investigation regarding the role of ticks in the epidemiology of CVL.


Assuntos
Doenças do Cão/epidemiologia , Leishmaniose Visceral/epidemiologia , Distribuição Animal , Animais , Brasil/epidemiologia , Reservatórios de Doenças/parasitologia , Reservatórios de Doenças/veterinária , Doenças do Cão/sangue , Doenças do Cão/parasitologia , Cães , Escolaridade , Feminino , Humanos , Leishmaniose Visceral/sangue , Leishmaniose Visceral/veterinária , Masculino , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Infestações por Carrapato/veterinária
19.
Exp Parasitol ; 215: 107919, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32442440

RESUMO

Rhipicephalus microplus, the cattle tick, is a major cause of economic losses in bovine production. Due to the widespread acaricidal resistance to commercially available products, as well as their toxicity and environmental impact, alternative control methods are required. Nanoformulations produced from plant extracts as bioactive substances are very promising as innovative acaricidal agents. Thus, the aim of this study was to evaluate the in vitro repellent activity of Pilocarpus spicatus essential oil and its nanoemulsion against R. microplus, using larval repellent test (RT). The essential oil was extracted by hydrodistillation, using a Clevenger-type apparatus. The nanoemulsion was prepared with 5% essential oil, 5% tween 80, and 90% water, using the phase inversion method (50 mg/mL). Limonene was the major component (46.8%) of the essential oil, as determined by gas chromatography-mass spectrometry (GC/MS) and confirmed by flame ionization detection (GC/FID). According to the RT results, the essential oil had a repellent activity greater than 69%, from concentrations of 3.12 mg/mL (69.81 ± 10%) to 50 mg/mL (98.10 ± 0.6%), whereas the nanoemulsion at 50 mg/mL presented repellent activities of 97.14 ± 1.37% and 97.89 ± 0.52% 6 and 10 h after treatment, respectively. These values regarding to total repellency were very close to those calculated for mortality corrected by Abbott's formula. The phase inversion method preserved the chemical and physical characteristics of the essential oil since both reached an equal repellent effect at the same concentration. Therefore, P. spicatus essential oil and nanoemulsion had excellent repellent activities against R. microplus larvae, demonstrating its potential for future use as an alternative for tick control.


Assuntos
Óleos Voláteis/farmacologia , Pilocarpus/química , Óleos Vegetais/farmacologia , Rhipicephalus/efeitos dos fármacos , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Emulsões/farmacologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Larva/efeitos dos fármacos , Limoneno/análise , Modelos Lineares , Óleos Voláteis/isolamento & purificação , Folhas de Planta/química , Óleos Vegetais/isolamento & purificação , Distribuição Aleatória , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária
20.
Res Vet Sci ; 131: 92-97, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32325299

RESUMO

Rhipicephalus microplus is the most significant tick of livestock and its control is particularly challenging due to its resistance to commercial acaricides. Pasture rotation is considered a management strategy that could help control R. microplus, however, the literature only contemplates mathematical models and little is known about the effects of this practice in the field. The objective of this work was to determine whether pasture rotation is an efficient method for controlling R. microplus. Two different experiments were performed that involved groups of continuous and rotational grazing bovines. Female ticks measuring 4.5-8.0 mm were counted on animals while larvae in pasture were counted using the flannel drag technique. Treatment for infested bovines was applied when the average group tick count was ≥30 females. The results showed that rotational grazing (with 20-day periods of rest) had a higher tick count on-host than continuous grazing (P < 0.05) and additional bovine treatment was needed. Sixty and 105 days were needed to re-infest and disinfest pasture of R. microplus larvae, respectively. The first treatment of bovines occurred 91 days after the animals were placed in a closed area. The results indicate that rotational grazing is not an efficient way to control R. microplus.


Assuntos
Criação de Animais Domésticos , Doenças dos Bovinos/prevenção & controle , Rhipicephalus/fisiologia , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária , Acaricidas/farmacologia , Criação de Animais Domésticos/métodos , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Larva/efeitos dos fármacos , Infestações por Carrapato/prevenção & controle
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