110 research outputs found
Differential diagnosis of three common Ixodes spp. ticks infesting songbirds of western Europe : Ixodes arboricola, I. frontalis and I. ricinus
The three most common Ixodes spp. ticks found on songbirds in Western Europe are Ixodes
frontalis, I. arboricola and I. ricinus. As the latter species is a generalist, it shares several
avian hosts with the two strictly ornithophilic species. Infestations of the three species can
overlap in time and space, implying that tick-borne pathogens maintained by the ornithophilic
ticks and their hosts could be bridged by I. ricinus to non-avian hosts. Whereas the
endophilic Ixodes arboricola only occurs in cavities, I. frontalis has been collected frequently
by flagging methods from understory vegetation, which is also the habitat of the fielddwelling
I. ricinus. As the latter two species have rather similar morphological
characteristics, they can easily be confused with each other. In this study, we present
scanning electron photomicrographs of all developmental stages of I. arboricola and I.
frontalis, and provide a differential diagnosis key to distinguish the ornithophilic ticks from I.
ricinus. In addition, we interpreted their phylogenetic associations based on mitochondrial
16S rDNA with other Ixodes spp. ticks (I. lividus, I. turdus, I. brunneus, I. vespertilionis, I.
trianguliceps, I. hexagonus, I. scapularis).Fund for Scientific Research âFlanders (FWO)http://www.elsevier.com/locate/ttbdishb201
New foci of Rhipicephalus microplus in West Africa
The invasive character of Rhipicephalus microplus was observed in Benin, the
second West-African country from which this ticks species has been collected after the
initial confirmed record in Ivory Coast in 2007. A cross-sectional study was carried out in
the Department of Mono to examine the presence of the tick R. microplus. The survey
covered 9 herds (villages) in an agro-ecological zone inhabited by agro-pastoralists,
including the State Farm of Kpinnou that imported Girolando cattle from Brazil. Almost
800 ticks were sampled from 36 cattle, on average four cattle per village. The morphological
identification revealed ticks of two different genera: Rhipicephalus and Amblyomma.
Rhipicephalus microplus was the only representative of the species previously
known as Boophilus or blue ticks. Its taxonomic identity was confirmed molecularly by
PCRâRFLP. A comparison was made with the situation of R. microplus in Brazil.The Belgian Development Cooperation (BDC) for the
financial support of this research project as part of a Masters programme offered by the Institute of Tropical
Medicine in Antwerp, Belgium.http://www.springerlink.com/content/100158/ab201
SNP analysis infers that recombination is involved in the evolution of Amitraz resistance in Rhipicephalus microplus
Rhipicephalus microplus, better known as the Asiatic cattle tick, is a largely invasive
ectoparasite of great economic importance due to the negative effect it has on agricultural
livestock on a global scale, particularly cattle. Tick-borne diseases (babesiosis and anaplasmosis)
transmitted by R. microplus are alarming as they decrease the quality of livestock
health and production. In sub-Saharan Africa, cattle represent a major source of meat and
milk, but this region of the world is severely affected by the Rhipicephalus microplus tick.
The principal method for tick control is the use of chemical acaricides, notably amitraz,
which was implemented in the 1990âs after resistance to other acaricides surfaced. However,
the efficiency of chemical control is hindered by an increase in the frequency of mutant
resistance alleles to amitraz in tick populations. Presently, the only way to assess amitraz
resistance is by means of larval packet tests, but this technique is time-consuming and not
particularly cost effective. The main aims of this study were three-fold. First, we attempted
to correlate two known SNPs in the octopamine/tyramine (OCT/Tyr) receptor with amitraz
resistance in South African field samples of R. microplus. Second, we calculated gametic
disequilibrium for these SNPs to determine whether they are randomly associated. Lastly,
we conducted a study to assess the evolutionary effects of recombination within the OCT/
Tyr receptor. Our results confirmed that the two SNPs are associated with amitraz resistance
in the South African tick strain, and that they are in gametic disequilibrium. Additionally,
recombination was detected in the OCT/Tyr receptor generating two recombinant haplotypes. These results are of concern to farmers in sub-Saharan Africa, and the emergence
of amitraz resistance should be closely monitored in future. Therefore, we present a
quick and affordable RFLP based diagnostic technique to assess amitraz resistance in field
samples of R. microplus.S1 Fig. Subpopulation structure of ticks across South Africa. Ticks from each farm were
placed into subpopulations (1â15) depending on the region from which they were collected.
Grid blocks were constructed 300 x 300 km over the country for accurate overall segregation of
populations. The farms from which tick samples were analyzed are indicated in the table, along
with their grid block number and province. Farm numbers correspond with sample number,
e.g. sample 44.1MF is sample 1 of female R. microplus from farm 44.S1 Table. GenBank accession numbers for all R. microplus OCT/Tyr receptor sequences.S2 Table. Genotypes of field samples of R. microplus ticks at the two published SNP positions.S3 Table. Rhipicephalus microplus larval packet test results.Funding was provided by (a) Gauteng
Department of Agriculture and Rural Development, C
Maritz-Olivier. (b) Zoetis South Africa (Pty) Ltd., C
Maritz-Olivier (c) National Research Foundation,
THRIP grant nr: 83890.http://www.plosone.orgam201
Morphological identification of ticks (Acari: Ixodidae) infesting donkeys (Equus asinus) in Maputo Province, Mozambique
Donkeys (Equus asinus) are rustic animals, but in Africaâs poorest regions, they can present multiple health problems, including tick infestation. The studyâs objective was to determine the species composition of ticks that infest donkeys in Maputo Province (Mozambique). Ticks were collected in five conveniently selected southern districts of Maputo Province (Moamba, MatutuĂne, Marracuene, Boane, and Matola) and were identified to species level using a stereoscopic microscope with the aid of dichotomous identification keys. In total, 500 ticks were collected from all 88 selected donkeys. Three genera of ticks were identified, namely Rhipicephalus (97.2%; 486/500), Amblyomma (2.2%; 11/500), and Hyalomma (0.6%; 3/500). Seven species were identified, of which Rhipicephalus evertsi evertsi with 50.4% (252/500) was the most prevalent, followed by Rhipicephalus appendiculatus (27.4%; 137/500), Rhipicephalus turanicus (11.6; 10/500), Rhipicephalus (boophilus) microplus (6.8; 20/500), Amblyomma hebraeum (2.2%; 11/500), Rhipicephalus sanguineus (1%; 5/500) and Hyalomma truncatum (0.6%; 3/500). Rhipicephalus evertsi evertsi occurred in all locations, whereas Hyalomma truncatum occurred only in the Boane district. Males were the most prevalent (67.2%; 336/500). The study revealed that donkeys in Maputo Province were infested with seven tick species of which R. evertsi evertsi was the main species.https://link.springer.com/journal/10493hj2023Veterinary Tropical Disease
First interception of Aedes (Stegomyia) albopictus in Lucky bamboo shipments in Belgium
Six gel-and five water-transported Dracaena braunii shipments originating from the South coast of China were screened for exotic mosquito species during a surveillance project on exotic vectors in Belgium. In November 2013, a live Aedes (Stegomyia) albopictus larva was detected in a gel substrate. This is the first direct evidence of the importation of Ae. albopictus on gel-transported Lucky bamboo. It also confirms that the importation risk of Ae. albopictus by transport of ornamental bamboo plants remains. In addition to the registration of appropriate biocides, a structured and permanent surveillance programme is needed in Belgium to allow for the early detection of invasive mosquito species and the timely implementation of control measures. JournalThe Federal Agency for the Safety of the Food Chain (FASFC)http://e-m-b.orgam201
Abondance saisonniÚre des tiques (Acari / Ixodidae) infestant le bétail dans quatre régions irriguées au Maroc
A study has been conducted between April 2007 and March 2008 to identify tick species infesting cattle in four irrigated regions in Morocco and to determine their abundance and phenology. The influence of climate, type of farm, age, sex and origin of the animals on the tick infestation was analyzed. 5,777 ticks have been collected and ten species identified, Hyalomma scupense 1,544 (26.7%), Hyalomma marginatum 1,489 (25.8%), Hyalomma lusitanicum 199 (3.4%), Hyalomma excavatum 554 (6.1%), Hyalomma dromedarii 59 (1.0%), Hyalomma impeltatum 26 (0.5%), Rhipicephalus sanguineus 266 (4.6%), Rhipicephalus turanicus 232 (4.0%), Rhipicephalus bursa 391 (10.2%) and Rhipicephalus (Boophilus) annulatus 1,017 (17.6%). The activity of most of the species was limited to spring and summer. According to the study, age and type of farm have a significant influence on the degree of infestation of cattle by ticks, whereas the origin and sex of the animals and climate had less influence.
Key words: Ticks, Ixodidae, Cattle, Irrigated areas, MoroccoUne Ă©tude a Ă©tĂ© menĂ©e entre Avril 2007 et Mars 2008 au niveau de quatre rĂ©gions irriguĂ©es du Maroc dans le but dâidentifier les espĂšces de tiques qui infestent les bovins et de dĂ©terminer leur abondance et leur phĂ©nologie. L'influence du climat, le type dâĂ©levage, l'Ăąge, le sexe et la race des bovins sur l'infestation des tiques ont Ă©tĂ© analysĂ©s. 5777 tiques ont Ă©tĂ© recueillies et dix espĂšces identifiĂ©es, Hyalomma scupense 1544 (26,7%), Hyalomma marginatum 1489 (25,8%), Hyalomma lusitanicum 199 (3,4%), Hyalomma excavatum 554 (6,1%), Hyalomma dromedarii 59 (1,0%), Hyalomma Impeltatum 26 (0,5 %), Rhipicephalus sanguineus 266 (4,6%), Rhipicephalus turanicus 232 (4,0%), Rhipicephalus bursa 391 (10,2%) et Rhipicephalus (Boophilus) annulatus 1017 (17,6%). L'activitĂ© de la plupart des espĂšces a Ă©tĂ© limitĂ©e au printemps et Ă lâĂ©tĂ©. Selon cette Ă©tude, l'Ăąge et le type d'Ă©levage ont une influence significative sur le degrĂ© d'infestation des bovins par les tiques, alors que l'origine et le sexe des bovins et du climat ont eu moins d'influence.
Mots clés : Tiques, Ixodidae, Bovins, Zones irriguées, Maro
Genetic diversity, acaricide resistance status and evolutionary potential of a Rhipicephalus microplus population from a disease-controlled cattle farming area in South Africa
The Southern cattle tick, Rhipicephalus microplus is a hematophagous ectoparasite of great veterinary and economic importance. Along with its adaptability, reproductive success and vectoring capacity, R. microplus has been reported to develop resistance to the major chemical classes of acaricides currently in use. In South Africa, the Mnisi community in the Mpumalanga region offers a unique opportunity to study the adaptive potential of R. microplus. The aims of this study therefore included characterising acaricide resistance and determining the level and pattern of genetic diversity for R. microplus in this region from one primary population consisting of 12 communal dip-stations. The level of acaricide resistance was evaluated using single nucleotide polymorphisms (SNPs) in genes that contribute to acaricide insensitivity. Additionally, the ribosomal internal transcribed spacer 2 (ITS2) gene fragments of collected individuals were sequenced and a haplotype network was constructed. A high prevalence of alleles attributed to resistance against formamidines (amitraz) in the octopamine/tyramine (OCT/Tyr) receptor (frequency of 0.55) and pyrethroids in the carboxylesterase (frequency of 0.81) genes were observed. Overall, the sampled tick population was homozygous resistant to pyrethroid-based acaricides in the voltage-gated sodium channel (VGS) gene. A total of 11 haplotypes were identified in the Mnisi R. microplus population from ITS2 analysis with no clear population structure. From these allele frequencies it appears that formamidine resistance in the Mnisi community is on the rise, as the R. microplus populations is acquiring or generating these resistance alleles. Apart from rearing multi-resistant ticks to commonly used acaricides in this community these ticks may pose future problems to its surrounding areas.Zoetis (Pty) Ltd., South Africa, the National Research Foundation Technology and Human Resources for Industry Programme (Grant number TP12082911252) and the Belgium Development Cooperation (DGD) FA3 project.http://www.elsevier.com/locate/ttbdis2017-06-30hb2016GeneticsVeterinary Tropical Disease
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