Variation of diazinon and amitraz susceptibility of Hyalomma marginatum (Acari: Ixodidae) in the Rabat-Sale-Kenitra region of Morocco.

In the present study, the acaricide susceptibility status of Hyalomma marginatum in Morocco was investigated in the Rabat-Sale-Kenitra region using the Larval Packet Test. The overall LC50 value for diazinon and amitraz was 115 ppm (95% CI: [104; 125]) and 22 ppm (95% CI: [21; 23]), respectively. The LC50 values varied significantly between the nine sampled locations (P<0.001) ranging from 75 ppm (95% CI: [65; 84]) in Ouelmes to 179 ppm (95% CI: [139; 201]) in Jorf El Melha for diazinon and from 18 ppm (95% CI: [15; 21]) in Skhirat to 28 ppm (95% CI: [24; 31]) in Ouelmes for amitraz. Sequencing of the target-site of diazinon, acetylcholinesterase 1 (AChE1), indicated that previously reported resistance mutations in AChE1 were absent in ticks from Jorf El Melha surviving 500 ppm diazinon. This study is the first report on the H. marginatum susceptibilty status to the most frequently used acaricides in Morocco and indicates that acaricide tick resistance is emerging.

Ticks and Tick-Borne Pathogens Abound in the Cattle Population of the Rabat-Sale Kenitra Region, Morocco.

Tick-borne pathogens cause the majority of diseases in the cattle population in Morocco. In this study, ticks were collected from cattle in the Rabat-Sale-Kenitra region of Morocco and identified morphologically, while tick-borne pathogens were detected in cattle blood samples via polymerase chain reaction assay and sequencing. A total of 3394 adult ixodid ticks were collected from cattle and identified as eight different tick species representing two genera, Hyalomma and Rhipicephalus. The collected ticks consisted of Hyalomma marginatum, Hyalomma anatolicum excavatum, Rhipicephalus sanguineus sensu lato, Rhipicephalus bursa, Hyalomma detritum, Hyalomma lusitanicum, Hyalomma dromedarii, and Hyalomma impeltatum. The overall prevalence of tick-borne pathogens in blood samples was 63.8%, with 29.3% positive for Babesia/Theileria spp., 51.2% for Anaplasma/Ehrlichia spp., and none of the samples positive for Rickettsia spp. Sequencing results revealed the presence of Theileria annulata, Babesia bovis, Anaplasma marginale, Theileria buffeli, Theileria orientalis, Babesia occultans, Anaplasma phagocytophilum, Anaplasma capra, Anaplasma platys, Anaplasma bovis, Ehrlichia minasensis, and one isolate of an unknown bovine Anaplasma sp. Crossbreeds, females, older age, and high tick infestation were the most important risk factors for the abundance of tick-borne pathogens, which occurred most frequently in Jorf El Melha, Sidi Yahya Zaer, Ait Ichou, and Arbaoua locations.

Acaricide resistance status and identification of resistance mutations in populations of the two-spotted spider mite Tetranychus urticae from Ethiopia.

The intensive use of pesticides is a common practice for the management of the two-spotted spider mite, Tetranychus urticae, in greenhouses and field farms of Ethiopia. However, incidence of resistance and possible resistance mechanisms in T. urticae populations from Ethiopia have not yet been studied. Here, we assessed the toxicity of various acaricides-bifenazate, abamectin, emamectin benzoate, profenofos, fenbutatin oxide, fenpyroximate, amitraz and chlorfenapyr-on T. urticae populations sampled from six flower greenhouse farms, three strawberry greenhouse farms, one field-grown vegetable farm and two wild populations. In parallel, all populations were screened for known target-site mutations. All tested populations were fully susceptible to bifenazate, abamectin, emamectin benzoate and profenofos, but resistant against fenbutatin oxide and fenpyroximate. Four populations showed considerable levels of resistance against amitraz and one population was resistant to chlorfenapyr. Several target-site mutations were identified in the tested populations, including G119S, A201S, T280A, G328A and F331W/C/Y in acetylcholinesterase and the F1538I and L1024V mutation in the voltage-gated sodium channel. The F1538I mutation was found in eight out of 12 populations, whereas the L1024V mutation was only found in two populations. The H92R mutation in the PSST subunit of complex I and the I1017F mutation in chitin synthase 1 was detected in half of the tested populations. The G326E and I321T mutations in the glutamate-gated chloride channel 3 were also detected, but more rarely, whereas mitochondrial cytochrome b mutations were not detected. The current study revealed multiple resistance patterns in Ethiopian T. urticae populations and together with the wide presence of target-site mutations, calls for the wise use of acaricides in the management of T. urticae in Ethiopia.

Methylation of selected CpG islands involved in the transcription of myeloperoxidase and superoxide dismutase 2 in neutrophils of periparturient and mid-lactation cows.

It is generally accepted that intracellular killing of microorganisms by production of reactive oxygen species (ROS) in the phagosome of the neutrophil is an important arm of innate defense. High-producing dairy cows are prone to periparturient metabolic and infectious diseases. Both myeloperoxidase (MPO) activity and ROS production decrease the day of parturition. Several studies have demonstrated changes in the expression of genes involved in, for example, metabolism and defense in the circulating neutrophil during peripartum. In this study, we wanted to further characterize the periparturient neutrophil in terms of its oxidative killing capacity by analyzing the oxidative burst at 3 levels. First, the ROS phenotype was evaluated using chemiluminescence. The cows (sampled within 24 h after parturition and at 135 d in milk) showed a significantly slower production of ROS at parturition. Both primiparous (n = 13) and multiparous (n = 12) cows were included in this study, but parity did not affect the kinetics of ROS production. Second, the expression of 11 genes involved in ROS production was measured in the same cows: cytochrome b-245 α and ß chain (CYBA, CYBB; coding for membrane-bound constituents of NADPH oxidase); neutrophil cytosolic factors 1, 2, and 4 (NCF1, NCF2, and NCF4); Rac family small GTPase 1 and 2 (RAC1 and RAC2; coding for regulatory proteins of NADPH oxidase); superoxide dismutase 2 (SOD2); catalase (CAT); myeloperoxidase (MPO; coding for enzymes involved in metabolizing downstream ROS); and spleen-associated tyrosine kinase (SYK; involved in signaling). During peripartum, a shift in expression in the oxidative killing pathway was observed, characterized by a downregulation of MPO and a simultaneous upregulation of the genes coding for NADPH oxidase. Third, as total DNA methylation is known to change during pregnancy, we investigated whether the observed differences were due to different methylation patterns. Promotor regions initiate transcription of particular genes; therefore, we analyzed the methylation status in annotated CpG islands of MPO and SOD2, 2 genes with a significant difference in expression between both lactation stages. The differences in methylation of these CpG islands were nonsignificant. High-throughput techniques may be necessary to obtain more detailed information on the total DNA methylation dynamics in bovine neutrophils and increase our understanding of how gene expression is controlled in neutrophils.

Reactive oxygen species generation by bovine blood neutrophils with different CXCR1 (IL8RA) genotype following Interleukin-8 incubation.

BACKGROUND: Associations between polymorphisms in the bovine CXCR1 gene, encoding the chemokine (C-X-C motif) receptor 1 (IL8RA), and neutrophil traits and mastitis have been described. In the present study, blood neutrophils were isolated from 20 early lactating heifers with different CXCR1 genotype at position 735 or 980. The cells were incubated with different concentrations of recombinant bovine IL-8 (rbIL-8) for 2 or 6 h and stimulated with phorbol 12-myristate 13-acetate (PMA) or opsonized zymosan particles (OZP). Potential association between CXCR1 genotype and production of reactive oxygen species (ROS) was studied. RESULTS: Although on single nucleotide polymorphisms (SNPs) may potentially affect CXCR1 function, SNPs c.735C > G and c.980A > G showed no association with ROS production with or without incubation of rbIL-8. Neutrophils incubated with rbIL-8 for 2 or 6 h showed higher PMA- and lower OZP-induced ROS production compared to control without rbIL-8. CONCLUSIONS: In the present study no association could be detected between superoxide production by isolated bovine neutrophils during early lactation and CXCR1 gene polymorphism. IL-8 showed to possess inhibitory effects on ROS generation in bovine neutrophils.