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Marc Desquesnes Ketsarin Kamyingkird Mathieu Pruvot Chanya Kengradomkij Geraldine Bossard Nachai Sarataphan Sathaporn Jittapalapong 《Preventive veterinary medicine》2009,90(3-4):233-241
Trypanosoma evansi is generally considered a mild pathogen in bovines. However, in Asia, acute and chronic signs have been observed in cattle, with high levels of parasitaemia, abortion and death. Investigations in Asian cattle are needed to better understand this epidemiological situation. To generate comparable data at a regional level, development and standardization of an antibody-enzyme linked immunosorbent assay for T. evansi (ELISA/T. evansi) was initiated and applied in an epidemiological survey carried out in dairy cattle in Thailand. A batch of 1979 samples was collected from dairy farms located throughout the country's four regions. Soluble T. evansi antigens initially produced in France were also produced in Thailand for comparison and technology transfer. Screening of 500 samples allowed us to identify reference samples and to determine the cut-off value of the ELISA. Seropositive animals – some of them confirmed by PCR – were found in the four regions, in 12 out of 13 provinces, in 22 out of 31 districts, in 56 farms out of 222 (25%, 95%CI ± 6%) and in 163 animals out of 1979 (8.2, 95%CI ± 1.2%). Estimated seroprevalence in 35 farms ranged between 1% and 30%, and in 21 farms it was >30%. Approximately 25% of survey cattle were exposed to the infection, in various situations. A sub-sample of 160 sera was tested on both antigens. Wilcoxon's (Z = 1.24; p = 0.22) and McNemars's tests (CHI2 = 3.55; p = 0.09) did not show any significant differences, showing that the locally produced antigen is suitable for further evaluation in the surrounding countries. Use of this standardized serological method will broaden knowledge of the prevalence and impact of the disease at the regional level in South-East Asia. Further validation of this ELISA will be necessary in other host species such as buffalo, horse and pig. 相似文献
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Tawin Inpankaew Tawisa Jiyipong Kannika Wongpanit Nongnuch Pinyopanuwat Wissanuwat Chimnoi Chanya Kengradomkij Xuenan Xuan Ikuo Igarashi Lihua Xiao Sathaporn Jittapalapong 《Tropical animal health and production》2014,46(2):487-490
The objectives of this study were to determine the individual and herd-level prevalence and genotype of Cryptosporidium and to identify putative risk factors associated with Cryptosporidium spp. infections in water buffaloes in northeast Thailand. Fecal samples from 600 water buffaloes of 287 farms in six provinces were collected and tested using DMSO-modified acid-fast staining and polymerase chain reaction. The overall prevalence of Cryptosporidium infections in buffaloes was 5.7 and 8.7 % among individual animals and herds, respectively. The provinces with highest infected Cryptosporidium were located in the Sakon Nakhon Basin in the northern part of the region. In addition, higher herd prevalence was observed among farms with more than five buffaloes (30 %) than those with five or less animals (16.2 %). Thirty (88.2 %) of the 34 Cryptosporidium-positive samples were Cryptosporidium parvum and four (11.8 %) were Cryptosporidium ryanae. 相似文献
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An Avena sterilis biotype was found to be highly resistant to aryloxyphenoxypropionate (APP) herbicides, especially diclofop-methyl. At the enzyme level, this biotype contained a modified acetyl-coenzyme A carboxylase (ACCase) with six-fold resistance to diclofop acid. Absorption and translocation of [14C]diclofop-methyl applied to the leaf axil of the two-leaf stage plants were similar in both susceptible and resistant biotypes. However, the rate of metabolism of [14C]diclofop was increased 1·5-fold in this resistant biotype compared to the susceptible. Experiments with tetcyclacis, a cytochrome P450 monooxygenase inhibitor, indicated that inhibition of this enhanced diclofop metabolism increased diclofop-methyl phytotoxicity in this biotype. Studies with ten individual families of the resistant biotype indicated that both mechanisms of resistance, an altered target site and enhanced metabolism, are present in each individual of the population. Hence, it is likely that these two mechanisms of resistance both contribute to resistance in this biotype. © 1997 SCI. 相似文献
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Ekkasit Phongphitak Chanya Maneechote Benjavan Rerkasem Sansanee Jamjod 《Weed Biology and Management》2014,14(3):159-166
Sprangletop (Leptochloa chinensis L. Nees) is a serious grass weed in direct‐seeded rice cropping systems in Thailand. One population of sprangletop, BLC1, was found to be resistant to fenoxaprop‐p‐ethyl at 62‐fold the concentration of a susceptible biotype, SLC1. This study elucidated the inheritance of resistance to fenoxaprop‐p‐ethyl in this sprangletop BLC1 genotype. The reaction to the herbicide at 0.12–2.4 mg ai L?1 was determined in the seedlings of self‐pollinated resistant BLC1, susceptible SLC1 and SLC1 that had been allowed to cross‐pollinate with BLC1. At 0.24 mg ai L?1, all the seedlings of SLC1 were killed, while 99% of BLC1 survived, along with 5% of the cross‐pollinated SLC1 seedlings, which were considered to be putative F1 hybrids. The root and shoot lengths of the F1 hybrids in 0.24 mg ai L?1 of fenoxaprop‐p‐ethyl, relative to those in the absence of the herbicide, were close to or the same as the resistant parent, indicating that the resistance is a nearly complete to complete dominant trait. One‐hundred‐and‐forty‐one of the F2‐derived F3 families were classified by their response to the herbicide at 0.24 and 0.48 mg ai L?1 into 39 homozygous susceptible : 72 segregating : 30 homozygous resistant, fitted with a 1:2:1 ratio at χ2 = 1.21 and P = 0.56, indicating that the resistance to fenoxaprop‐p‐ethyl in the sprangletop BLC1 genotype is controlled by a single gene. 相似文献
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Anupong Wongtamee Chanya Maneechote Tonapha Pusadee Benjavan Rerkasem Sansanee Jamjod 《Genetic Resources and Crop Evolution》2017,64(1):23-39
Weedy rice (Oryza sativa f. spontanea Baker) is one of the most serious weeds in direct-seeded rice production; adversely affecting rice areas and yield in Thailand. The objectives of this study were to evaluate the level of morphological and agronomical variation and the level and pattern of genetic diversity and population structure of weedy rice populations in Thailand. Sixty-three weedy rice populations collected from three rice production areas of Thailand were sampled over four rice cultivation seasons to study phenotypic characteristics, genetic diversity and population structure. All analysis included comparison with seven cultivated rice varieties and seven local common wild rice populations. The results demonstrated considerable genetic and morphological variation, population structure, and changing dynamics of Thai weedy rice populations, both within and between regions and growing seasons. Phenotypic and genotypic variations and population structure of weedy rice populations changed temporally, with a trend over five years toward greater similarity to companion crop rice varieties. The ongoing gene flow, combined with ecological conditions created by farmers’ selection and agronomic practices, may enhance fitness and adaptability of weedy rice populations and stimulate the evolution of invasiveness in weedy rice plants. The adaptive evolution of weedy rice tended to parallel cultivated rice for high adaptation to the agronomic practices, possibly including selection for crop mimicry, which has led to the convergence of weedy populations phenotypically and genetically with the companion crop rice. 相似文献
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