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bovine babesiosis in dual purpose calves in the state of yucatan, mexico.thirty-eight dual purpose calves in the 3 agricultural zones of the state of yucatan, mexico were monitored for antibodies to babesia bovis and b. bigemina from close to birth up to 12 months of age. the results showed that infection with both parasites is widespread throughout the 3 zones. many of the animals had produced antibody to both parasites by 6 months of age indicating high transmission rates resulting in enzootic stability for both parasites. any changes to agricultural practices in t ...19989719829
a common high molecular weight antigen of babesia bovis isolates from mexico.cattle from an area of mexico endemic with babesia bovis infections have a dominant antibody response to a 152kda antigen of the tamaulipas strain of b. bovis. a mab termed pb/5, showing a specific reactivity to this 152kda antigen in western blots, was identified. the mab which reacted with the blunt end of b. bovis in an indirect fluorescent antibody test also reacted to a 152kda antigen in two other isolates (nuevo leon and yucatan), and a 175kda antigen in the huasteca b. bovis isolate from ...200010675745
development of amitraz resistance in field populations of boophilus microplus (acari: ixodidae) undergoing typical amitraz exposure in the mexican tropics.the purpose of this study was to determine the effect of amitraz selection pressure on the development of resistance in field populations of boophilus microplus in the mexican tropics. three farms (fa(1), fa(2) and fa(3)) in yucatan, mexico, were selected in this study. amitraz was applied as a whole body sprays to all cattle on each farm for tick control once monthly for 15 months. from each farm, 20-30 b. microplus engorged females were collected every 3 months. the modified larval immersion t ...200818242859
seroprevalence of neospora caninum antibodies in beef cattle in three southern states of mexico.the aims of the present study were to examine the seroprevalence of neosporosis in beef herds from three southern states of mexico and determine the association with several risk factors. a cross-sectional serological survey for neospora caninum was carried out by sampling a total of 596 animals from 31 herds in chiapas, veracruz, and yucatan states and tested using an elisa assay (idexx) to detect anti-n. caninum antibodies. the overall prevalence was 11.6%, (95% ci: 0.93-0.14), however, the pr ...200919016341
first report of the cattle tick rhipicephalus microplus resistant to ivermectin in mexico.three cattle farms with ticks, rhipicephalus microplus, thought to be resistant to ivermectin in yucatan, mexico were studied (sfdo, spn, luady). each field-population was collected and tested twice several months apart. the larval immersion test was used on the progeny of collected adult females to test the susceptibility to ivermectin. dose-mortality regressions, lethal concentrations (lc), their confidence intervals and slope were estimated by probit analysis. resistance ratios (rr) were dete ...201019951828
using msa-2b as a molecular marker for genotyping mexican isolates of babesia bovis.variable merozoite surface antigens of babesia bovis are exposed glycoproteins having a role in erythrocyte invasion. members of this gene family include msa-1 and msa-2 (msa-2c, msa-2a(1), msa-2a(2) and msa-2b). to determine the sequence variation among b. bovis mexican isolates using msa-2b as a genetic marker, pcr amplicons corresponding to msa-2b were cloned and plasmids carrying the corresponding inserts were purified and sequenced. comparative analysis of nucleotide and deduced amino acid ...200919931189
[bull horn wounds. a 1 year experience at the o'horán general hospital mérida, yucatán, méxico].taurine medicine has been able to open the way to the advance of science and to the adaptation of science to the patient with a bull horn wound so that at present, 95% of patients now survive gorings that were fatal in earlier times.200319753722
prevalence of abortion and stillbirth in a beef cattle system in southeastern mexico.prenatal mortality is an important cause of production losses in the livestock industry. this study estimates the prevalences of abortion and stillbirth in a beef cattle system and determines the significance of some risk factors, in the tropics of mexico. data were obtained from a zebu cattle herd and their crosses with bos taurus breeds, in yucatan, mexico. the logit of the probability of an abortion or stillbirth was modeled using binary logistic regression. the risk factors tested were: year ...200919449114
[isolation of a field strain of babesia bigemina (piroplasma: babesiidae) and establishment of in vitro culture for antigen production].isolation of a field strain of babesia bigemina (piroplasma: babesiidae) and establishment of in vitro culture for antigen production. bovine b abesiosis, caused by babesia bigemina, is a barrier for livestock development; it results in high economic loss to mexican livestock. control requires adequate antigens for diagnosis and vaccination programs. however, because of antigenic variation among babesia strains, it is necessary to use antigens prepared from local strains. the purpose of the pres ...200718457120
detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus-3 in beef cattle of yucatan, mexico.we collected blood samples from 756 > or =2-year-old cattle in 54 herds in yucatan, mexico, and used all of those to determine the antibody seroprevalences (in an indirect enzyme-linked inmunosorbance assay) to bovine respiratory syncytial virus (brsv) and risk factors for animal-level seropositivity. we used 728 of the same samples (from 52 of the same herds) to do the same for parainfluenza virus-3 (piv3). cattle were selected by two-stage cluster sampling. herd-level and animal-level risk fac ...200717590461
spatial distribution of acaricide profiles (boophilus microplus strains susceptible or resistant to acaricides) in southeastern mexico.the ability of boophilus microplus strains to be susceptible (-) or resistant (+) to amidines (am), synthetic pyrethroids (sp), and/or organo-phosphates (op) (or acaricide profiles) was investigated in 217 southeastern mexican cattle ranches (located in the states of yucatán, quintana roo, and tabasco). three questions were asked: (1) whether acaricide profiles varied at random and, if not, which one(s) explained more (or less) cases than expected, (2) whether the spatial distribution of acarici ...200717349747
productivity of different cow genetic groups in dual-purpose cattle production systems in south-eastern mexico.the objective was to evaluate the effect of cow genetic group, nutritional level and their interaction on some economically important traits of dual-purpose herds managed under field conditions. nine herds were monitored during a production cycle in yucatan, mexico. herds were grouped into four nutritional levels (nl) based on the metabolizable energy (me) apparently available on pasture, nutritional management, and milk production. cows were classified into three genetic groups (gg): low (< or ...200617265774
prevalence and potential risk factors for amitraz resistance in boophilus microplus ticks in cattle farms in the state of yucatan, mexico.southern cattle tick, boophilus microplus, control in the mexican tropics is based on the application by spray, dip or pour-on of acaricides. in mexico the first report of ticks resistant to amitraz was reported in 2002. amitraz resistance affecting the cattle industry of yucatan state, mexico, has not been investigated. a cross-sectional study was carried out in order to investigate the possible association between management risk factors and the prevalence of b. microplus ticks resistant to am ...200616730819
roles played by esterase activity and by a sodium channel mutation involved in pyrethroid resistance in populations of boophilus microplus (acari: ixodidae) collected from yucatan, mexico.pyrethroid resistance in boophilus microplus (canestrini) (acari: ixodidae) was studied by correlating discriminating-dose (dd) bioassay results and esterase activity or the frequency of a sodium channel mutation known to be involved in pyrethroid resistance in nine field strains of b. microplus from yucatan, mexico. two tick strains (p67 and b74) were identified as susceptible to cypermethrin, deltamethrin, and flumethrin by dd, one strain (p65) was susceptible to cypermethrin and resistant to ...200516465743
prevalence and potential risk factors for organophosphate and pyrethroid resistance in boophilus microplus ticks on cattle ranches from the state of yucatan, mexico.a cross-sectional study was carried out in order to investigate the association between management risk factors and the prevalence of organophosphate (op) and synthetic pyrethroid (sp) resistance in boophilus microplus ticks in yucatan state, mexico. ninety-eight cattle ranches were randomly selected and a sample of 20-30 engorged female b. microplus ticks was collected at each. the modified larvae packet test was used to detect op and sp tick resistance. a questionnaire was administered on each ...200616413971
genetic and non-genetic effects on productive and reproductive traits of cows in dual-purpose herds in southeastern mexico.data on productive and reproductive performance of cows in dual-purpose herds were analyzed to determine the effect of some environmental and genetic factors on saleable milk yield (smy), lactation length (ll), daily saleable milk per lactation (dmyl), calving interval (ci), and daily saleable milk per calving interval (myci) in dual-purpose herds in yucatan, mexico. repeatabilities (re) for these traits were also estimated. data were obtained from monthly visits to 162 herds from 1996 to 2000. ...200516342032
nontyphoidal salmonella from human clinical cases, asymptomatic children, and raw retail meats in yucatan, mexico.we report the results of a 3-year salmonella surveillance study of persons with diarrhea; asymptomatic children; and retail pork, poultry, and beef in yucatan, mexico.200616323087
bovine viral diarrhoea virus in beef cattle herds of yucatan, mexico: seroprevalence and risk factors.a survey of bovine viral diarrhoea virus (bvdv) infection was carried out from june 2001 to july 2002 in a non-vaccinated beef cattle population from the livestock region of yucatan, mexico, to assess seroprevalence and identify risk factors related to seroprevalence. the aim was also to estimate the intra-herd correlation (r(e)) and design effect (d) of bvdv seropositivity. cattle were selected by a two-stage cluster sampling. blood samples were collected from 560 animals originating from 40 he ...200516153725
the effect of management factors on the seroprevalence of anaplasma marginale in bos indicus cattle in the mexican tropics.a cross-sectional study with a two-stage design and proportional distribution was carried out to determine the effect of management factors on the seroprevalence of anaplasma marginale in bos indicus cattle in the mexican tropics. serum was obtained from 384 cattle aged 1-2 years on 92 farms. the number of samples was proportionally distributed according to the number of farms in eastern yucatan. antibody activity against a. marginale was assessed using the card agglutination test. a primary scr ...200414998312
seroprevalence of and risk factors for leptospiral antibodies among cattle in the state of yucatan, mexico.sera obtained from cattle in the state of yucatan, mexico, were screened using the microscopic agglutination test against 13 serovars of leptospira interrogans. a total of 62.8% (461/734) cows were positive for one or more serovars. this seroprevalence probably reflects infection because vaccination against leptospirosis has not been practised in yucatan. the most common antibodies detected were those against antigens of serovars hardjo (54.1%) and tarassovi (53.3%). region was the only risk fac ...200314509536
prevalence of benzimidazole resistant nematodes in sheep flocks in yucatan, mexico.thirty-eight sheep flocks, located in three municipalities in the eastern yucatan, mexico, were surveyed for gastrointestinal nematodes resistant to benzimidazole (bzd) anthelmintics (ah). on each flock, 30 sheep were randomly distributed into two groups of 15 animals: albendazole group (5mg/kg bw) and untreated control group. animals were refrained from any food (either browsing/grazing or supplement) for a period of 16 h prior to treatment. faecal egg counts (fec) and larval cultures were perf ...200312732464
seroprevalence of and risk factors for infectious bovine rhinotracheitis in beef cattle herds of yucatan, mexico.the main objective of this cross-sectional study was to estimate the seroprevalence of infectious bovine rhinotracheitis (ibr) in a population of non-vaccinated beef cattle in the livestock region of yucatan, mexico and to determine potential risk factors related to the seroprevalence. also, we estimated the intraherd correlation (r(e)) and design effect (d) of ibr seropositivity. cattle were selected by two-stage cluster sampling. blood samples were collected from 564 animals from 35 herds. ser ...200312609465
effect of moxidectin against natural infestation of the cattle tick boophilus microplus (acarina: ixodidae) in the mexican tropics.the study was divided in to two trials and carried out in a ranch in eastern yucatan state, mexico. in the first trial, two groups of 15 bostaurusxbosindicus heifers, 6-12 month of age and naturally infested with boophilus microplus ticks were used. heifers in group 1 were treated with a 1% injectable formulation of moxidectin at the dose of 0.20mg/kg body weight by subcutaneous injection. the other group remained as untreated controls. number of immature and engorging female ticks were assessed ...200312531295
[serum monitoring of igg and igm babesia bigemina (haemosporidia: babesiidae) antibodies in calves from the mexican tropics].antibody dynamics (igg and igm) against babesia bigemina was studied on 41 under 15 days of age from three ranches (r1, r2 and r3) in yucatan, mexico. blood samples were collected every 30 days, for eight months. sera were tested by the indirect fluorescent antibody method to detect igg and igm. overall igm seroprevalence during the calves first eight months of life was 17.1% without relation to age. overall igg seroprevalence was 66.8%, increasing with age. seroprevalence in r1, r2 and r3 were ...199810751937
management factors associated with babesia bovis seroprevalence in cattle from eastern yucatán, mexico.the effect of management on the seroprevalence of babesia bovis was studied in 399 bos indicus cattle 1-2 years old from 92 farms in the eastern yucatán, méxico. the management factors studied were: farm-type, production system, herd size, farm size, stocking density, vector control, dipping interval, type of dipping, type of acaricide and cattle introduction to the farm. a cross-sectional study was carried out (2-stage cluster sampling). the number of serum samples was proportionally distribute ...199910423779
heritability and factors affecting growth traits and age at first calving of zebu beef heifers in south-eastern mexico.information for this study was obtained from a commercial beef enterprise located in the subhumid tropics of yucatan, mexico. data from 664 females of different zebu breeds born from 1972 to 1983 were considered for analyses. weaning and 18-month weights were adjusted to 240 (w240) and to 550 (w550) days of age, respectively. the statistical model included the fixed effects of years of birth, season of birth, age of dam at calving, breed of heifer and the random effect of sire within breed. arit ...19979316237
use of multiplex polymerase chain reaction-based assay to conduct epidemiological studies on bovine hemoparasites in mexico.a study was conducted to test the applicability of a polymerase chain reaction (pcr)-based approach for the simultaneous detection of the bovine hemoparasites babesia bigemina, b. bovis and anaplasma marginale. bovine blood samples from cattle ranches of a previously determined enzootic zone in the yucatan peninsula of mexico, were collected from peripheral blood and processed for pcr analysis. blood samples were subjected to dna amplification by placing an aliquot in a reaction tube containing ...19938134659
[leptospirosis in the yucatan. serological study in humans and animals]. 19846474260
evaluation of a colorimetric babesia bigemina-dna probe within an epidemiological survey.an epidemiological survey was conducted in southeast mexico, in an effort to establish the serological reactivity and carrier status to babesia bigemina of an indigenous cattle population. the prevalence was obtained through the indirect fluorescent antibody test (ifat), using an in vitro culture-derived b. bigemina antigen. a specific, digoxigenin-coupled, approximately 6 kb b. bigemina-dna probe (bbdp), was used to indicate the presence of the parasite. serum samples from 925 animals of all ag ...19921343694
survey of rhipicephalus microplus resistance to ivermectin at cattle farms with history of macrocyclic lactones use in yucatan, mexico.engorged females of rhipicephalus microplus were collected from 30 cattle farms in yucatan, mexico to evaluate ivermectin resistance. the larval progeny of each tick sample were produced in laboratory and evaluated using the larval immersion test to obtain the larval mortality. concentration-mortality data were subjected to probit analysis to generate lethal concentrations (lc). resistance ratio (rr) of each tick sample was calculated by dividing its lc with that of an ivermectin-susceptible str ...201020570047
gene expression in caged fish as indicators of contaminants exposure in tropical karstic water bodies.karstic areas in yucatan are very permeable, which allows contaminants to move rapidly into the aquifer. in the present study, we evaluated gene expression of vitellogenin (vtg) and cytochrome p-450 1a (cyp1a) in caged juvenile zebrafish deployed for 15 days in 13 different water bodies, cenotes and aguadas, throughout karstic region of the yucatan peninsula. gene expression was evaluated using qrt-pcr. results indicated induction of vtg in 7 water bodies with respect to reference cage. the high ...201122014761
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