RESUMO
A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.
RESUMO
This study evaluated potential relationships between parasite egg/oocyst outputs in cow-calf beef herds located within the United States Northern Great Plains and herd longitude and latitude. Management of study herds was typical of herds from this region. Parasite egg/oocyst counts were measured from 10 cows and 5 calves selected from each herd near the end of the traditional grazing season (October 1993). The types and numbers of eggs and oocysts recovered from both cows and spring-born calves were consistent with those described in other studies. No significant relationship between fecal egg/oocyst counts and latitude was observed in calves or cows. Monezia egg output exhibited no significant correlation with longitude for calves or cows. In cows, a significant negative correlation was detected between coccidian oocyst counts and herd longitude but not between helminth egg counts and longitude. In calves, Nematodirus, trichostrongyle and Trichuris egg output and coccidian oocyst output were all negatively correlated with longitude. This negative correlation suggests that nematode populations within the study area decreased slightly from an east to west direction.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Fezes/parasitologia , Oocistos , Óvulo , Doenças Parasitárias em Animais/epidemiologia , Animais , Bovinos , Feminino , Masculino , Meio-Oeste dos Estados Unidos/epidemiologia , Doenças Parasitárias em Animais/parasitologiaRESUMO
North American bison (Bison bison) producers face many challenges, including the potential clinical and economics problems caused by trichostrongyle nematodes within their herds. Little is known about the prevalence, intensity, geographical distribution and clinical significance of these parasites in commercial bison herds, even from regions where bison production has become popular. This study involved a large herd of bison from eastern South Dakota that was experiencing clinical parasitism due to a temporary over-stocking problem. After documenting fecal egg counts (FECs) and trichostrongyle genera present among the 3 main age-categories (i.e. adults, yearlings, calves) of bison during this heavily infected grazing season, the effects of doramectin treatment on the different age groups was also evaluated. This is the first bison study using PCR to identify genera of trichostrongyles in fecal samples. Virtually all 103 bison fecal samples from all 3 age classes were shedding trichostrongyle eggs by the end of the season, and the mean FECs were 34 eggs/g (EPG) among the cows, 125 EPG in the yearlings, and 186 EGP among calves. Based upon this heavily-infected herd, there is evidence that the susceptibility of bison to trichostrongyles is more similar to beef cattle than to sheep. Other parasites such as Moniezia, Nematodirus, Trichuris, and coccidians were also identified in these samples. All but 3 of the 51 samples analyzed with PCR shown at least 1 trichostrongyle genera. Ostertagia was detected in 68.6% of the samples, Cooperia in 80.39%, Haemonchus in at least 73% and Trichostrongylus in 16% of the herd. Most commonly, bison were infected with combinations of Haemonchus/Ostertagia/Cooperia. After treatment with doramectin, the mean FECs dropped by 99.9% for all of the bison age classes.
Assuntos
Anti-Helmínticos/uso terapêutico , Bison , Ivermectina/análogos & derivados , Trichostrongyloidea/isolamento & purificação , Tricostrongiloidíase/veterinária , Animais , Feminino , Ivermectina/administração & dosagem , Ivermectina/uso terapêutico , Masculino , Tricostrongiloidíase/classificação , Tricostrongiloidíase/tratamento farmacológicoRESUMO
The objective of this study was to evaluate the use of a single pasture, limited treatment methodology to assess the impact of gastrointestinal nematodes on weight gain in grazing cattle. From a group of 450 British crossbred, yearling spayed heifers, 60 animals were randomly selected (prospective randomization) prior to placement on summer pasture. Each of these 60 animals was weighed, a fecal sample obtained for nematode egg count and a uniquely numbered ear tag applied. A randomly assigned group of 30 received treatment with one ivermectin sustained release bolus, while the remaining 30 served as non-treated controls. The treatment and control groups rejoined the remaining non-treated 390 animals, and were grazed as a single group for 165 days. At grazing conclusion, treatment and control cattle were individually weighed, and fecal samples obtained for nematode egg counts. Treatment was associated with a 0.064 kg per grazing day gain increase, or a 10 kg increase over the grazing season (P = 0.02). Nematode egg counts at grazing initiation were not different between treatment and control (P = 0.30), though egg counts in treated cattle at study end were lower than control (P < 0.0001). Results of this study support the use of a single pasture limited treatment approach for measuring the effect that internal nematodes have on weight gain in grazing cattle under commercial range conditions.
Assuntos
Doenças dos Bovinos/parasitologia , Gastroenteropatias/veterinária , Infecções por Strongylida/veterinária , Estrongilídios/crescimento & desenvolvimento , Animais , Peso Corporal , Bovinos , Doenças dos Bovinos/epidemiologia , Fezes/parasitologia , Feminino , Gastroenteropatias/epidemiologia , Gastroenteropatias/parasitologia , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , South Dakota/epidemiologia , Estatísticas não Paramétricas , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/parasitologiaRESUMO
The main purpose of this study was to determine the effects of cortisone on the number and size of primary Echinococcus multilocularis cysts developing in a moderately resistant strain of mice, i.e., C3H/HeJ. Computerized image analysis was used to measure the surface area occupied by hydatid cysts 10 wk after inoculation of the mice with E. multilocularis eggs. Our second objective was to compare the infectivity of primary E. multilocularis hydatid cysts in C57BL/6J-Ay/a (lethal yellow) mice with that in C57BL/6J-a/a (non-agouti black) mice. The data obtained show no difference between the C3H/HeJ and C57BL/6J-a/a strains of mice; yet, the image analysis method was able to detect a slight increase in the total cyst size within the Ay/a mutant of the C57BL/6J strain. Treatment of C3H/HeJ mice with cortisone drastically increased both the number of cysts and the average size of each cyst when the treatment occurred early in the infection.
Assuntos
Anti-Inflamatórios/uso terapêutico , Cortisona/uso terapêutico , Equinococose/tratamento farmacológico , Animais , Anti-Inflamatórios/farmacologia , Carnívoros , Cortisona/farmacologia , Equinococose/imunologia , Equinococose/patologia , Echinococcus/efeitos dos fármacos , Echinococcus/crescimento & desenvolvimento , Echinococcus/imunologia , Genes Letais/imunologia , Processamento de Imagem Assistida por Computador , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , Imunidade Inata/imunologia , Fígado/parasitologia , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos MutantesRESUMO
Methods for killing Echinococcus multilocularis eggs within stool or intestinal samples, without damaging the diagnostic value of the sample, would significantly reduce the risk of animal health providers acquiring alveolar hydatid disease. The first objective of this study was to determine whether E. multilocularis eggs located in fox intestines can survive storage at -70 C for at least 4 days. Results showed that none of 72,000 E. multilocularis eggs remained infectious to defined strains of mice under these conditions, yet, similar eggs recovered from nonfrozen carcasses stored at 4 C for the same time period were viable. The structural identities of adult worms and eggs were not significantly altered by the freezing and thawing processes. These results indicate that ultracold temperatures can be used to kill or inactivate E. multilocularis eggs, making them safe to handle when diagnosing this parasite in definitive hosts. The second objective of this study was to determine whether E. multilocularis eggs could survive freezing to -70 C if commonly used cryopreservation protocols were used. The use of the cryoprotectant solution, 5% dimethyl sulfoxide-35% saline-60% lamb serum, with a -1 C/min freezing rate was unable to prevent the eggs from being killed by freezing to -70 C. Rapid cooling by plunge freezing into liquid nitrogen was also lethal to E. multilocularis eggs. Only a few of the many potential cryopreservation protocols were tested in this study, so it is not yet possible to completely rule out the possibility of preserving these eggs at ultralow temperatures, but it does indicate that temperatures below -70 C are lethal to eggs even under favorable storage conditions.
Assuntos
Criopreservação/veterinária , Equinococose Hepática/veterinária , Echinococcus/fisiologia , Raposas/parasitologia , Animais , Equinococose Hepática/parasitologia , Congelamento , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBARESUMO
The effects of tunicamycin (TM) on the uptake and incorporation of tritiated galactose into the tegumental membrane and carcass from adult Hymenolepis diminuta were examined to assess the potential usefulness of this inhibitor for studying the function of the tapeworm surface glycocalyx. Hymenolepis diminuta adults (11 days old) were preincubated for 1 hr, pulsed for 30 min with [3H]galactose and [14C]leucine, and chased for 2 hr; replicate experiments were conducted in which all media contained no TM or TM at 10 micrograms/ml. Tunicamycin significantly inhibited the incorporation of tritiated galactose into the tapeworm's carcass and 30,000-g tegumental membrane fraction. Incorporation of tritiated galactose into the tapeworm's tegumental surface membrane also was inhibited significantly when expressed relative to the incorporation of [14C]leucine. Tunicamycin did not affect the amounts of free, i.e., soluble, [3H]galactose or [14C]leucine recovered from the tapeworms not did it affect the short-term (2 min) uptake of [3H]galactose by tapeworms. Thus, the inhibitory effect of TM appears to be at the level of protein glycosylation rather than carbohydrate (galactose) transport. The data indicate that TM might be useful for producing tapeworm surface membranes with diminished carbohydrate moieties.
Assuntos
Antibacterianos/farmacologia , Galactose/metabolismo , Hymenolepis/efeitos dos fármacos , Tunicamicina/farmacologia , Análise de Variância , Animais , Glicosilação/efeitos dos fármacos , Hymenolepis/metabolismo , Leucina/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , TrítioRESUMO
Two new species of Eimeria were observed in the feces of captive white-tailed deer fawns, Odocoileus virginianus, from Alabama. The first new species was easily recognized because of its small size. Sporulated oocysts are spherical, average 10.2 by 10.0 microm, and lack a micropyle and oocyst residuum. Oocysts contain a polar granule and elongate-ellipsoidal sporocysts that measure 6.7 by 3.1 microm. A Stieda body is present on the sporocysts. Oocysts were observed in the feces, and gamonts and oocysts were observed in the jejunum of a month-old fawn from Minnesota that died from enteritis due to this species. Oocysts of this small species were present in 5 of the 6 white-tailed deer fawns examined. Oocysts of a second new species are ellipsoidal and average 29.5 by 24.6 microm. The oocyst encloses an oocyst residuum, polar granule, and elongate-ellipsoidal sporocysts that average 16.0 by 9.0 microm. A Stieda body and substieda body are present on the sporocysts. Oocysts of the second new species were present in 4 of the 6 white-tailed deer fawns examined. Oocysts of E. ivensae are ovoid or flask-like and average 32.0 by 20.8 microm. The oocyst wall is rough, contains a micropyle, and encloses elongate-ellipsoidal sporocysts that average 16.5 by 7.8 microm. A Stieda body is present on the sporocysts. Oocysts of E. ivensae were present in 4 of the 6 white-tailed deer fawns. Oocysts of E. odocoilei are spherical or slightly subspherical and measure 24.7 by 21.5 microm. They enclose ovoid sporocysts that average 12.7 by 8.8 microm. A Stieda and substieda body are present on the sporocyst. Oocysts of E. odocoilei were present in 4 of the 6 white-tailed deer fawns.
Assuntos
Coccidiose/veterinária , Cervos/parasitologia , Eimeria/isolamento & purificação , Animais , Coccidiose/parasitologia , Eimeria/classificação , Fezes/parasitologia , Contagem de Ovos de Parasitas/veterinária , VirginiaRESUMO
The strobilocercus stage of the cat tapeworm Taenia taeniaeformis is surrounded by a single syncytial sheet of cytoplasm called the tegument. The outer membrane of the tegument covers both the scolex/strobila (S/S) and the bladder portions of the strobilocercus, but only the S/S region is resistant to intestinal digestion. It has been suggested that the glycocalyx, the surface-exposed glycoconjugates of the outer membrane, may serve to insulate underlying surface membrane components from digestion. In this study, we used lectin binding to test the hypothesis that the glycocalyx of the S/S is different from that of the bladder and that this may serve as the resistance mechanism of the S/S to digestion. Biotin-labeled lectins and an avidin-glucose oxidase detection system were applied to whole strobilocerci and to 1-microm epon-araldite plastic-embedded sections. Lectins bound to either both regions of the strobilocerci, to the S/S regions only, or did not bind at all. The restriction of some glycoconjugates to the glycocalyx of the S/S region only is consistent with our hypothesis.
Assuntos
Carboidratos/análise , Taenia/química , Taenia/ultraestrutura , Animais , Gatos , Histocitoquímica , Lectinas , Microscopia EletrônicaRESUMO
Echinococcus multilocularis causes a rare but potentially lethal zoonotic disease in humans. This tapeworm has been known to be endemic in foxes (Vulpes vulpes) and coyotes (Canis latrans) within the northern United States since the 1960s. One purpose of this study was to provide recent data on the prevalence of E. multilocularis in foxes and coyotes from eastern South Dakota. In a survey conducted from 1987 to 1991 and involving 137 foxes and 9 coyotes from this area, 74.5% of the foxes and 4 of the coyotes were infected. To assess the possible prevalence of alveolar echinococcosis in a group at presumptive high risk, we also conducted a serological survey of members of the South Dakota Trappers Association in 1990 and 1991. Serum samples from 115 trappers were evaluated for the presence of E. multilocularis antibodies using enzyme-linked immunosorbent assay tests involving a purified antigen called Em2, a crude E. multilocularis antigen, and a recombinant E. multilocularis antigen called II/3-10. None of the trappers showed antibody evidence for the presence of E. multilocularis. Roughly half of the surveyed individuals had trapped more than 50 foxes during their life, and almost one-fourth had trapped more than 1,000 foxes.
Assuntos
Carnívoros/parasitologia , Equinococose Hepática/epidemiologia , Raposas/parasitologia , Doenças Profissionais/epidemiologia , Zoonoses , Adolescente , Adulto , Distribuição por Idade , Idoso , Animais , Animais Selvagens , Anticorpos Anti-Helmínticos/sangue , Autopsia/veterinária , Criança , Equinococose Hepática/transmissão , Echinococcus/imunologia , Humanos , Pessoa de Meia-Idade , Prevalência , South Dakota/epidemiologiaRESUMO
This article has described current recommendations for nutritional support of the burned pediatric patient. A checklist for monitoring the progress of pediatric burn patients from admission to discharge is included.
Assuntos
Queimaduras/terapia , Nutrição Enteral , Nutrição Parenteral Total , Criança , Ingestão de Energia , Alimentos Formulados , Humanos , Nutrição ParenteralRESUMO
Pediatric patients with severe burns exhibit growth delays. This study investigates weight history after discharge. Twenty-seven children with burns covering more than 40% of their total body surface area were studied from admission until 2 to 4 years after injury. Younger children decreased their weights for height; older patients mainly increased theirs. Alterations during the first year of follow-up correlated with alterations until 2 and 3 years (r = 0.91 and r = 0.76, respectively). Once initiated, net weight gain continued, whereas net weight losses diminished with time. Preburn equivalent weights, however, could not be reached within 3 years. Special attention must be paid to children who are close to or less than their ideal body weights at the time of injury, especially if they are young, because further weight loss may be critical. Outpatient nutritional therapy should be focused to control these developments.
Assuntos
Distinções e Prêmios , Queimaduras/metabolismo , Redução de Peso , Adolescente , Distribuição por Idade , Metabolismo Basal , Queimaduras/reabilitação , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Masculino , Fenômenos Fisiológicos da Nutrição , Alta do Paciente , Estudos Retrospectivos , Aumento de Peso/fisiologia , Redução de Peso/fisiologiaRESUMO
A previous study indicated that formulas for determining caloric requirements of severely burned children overestimated their needs. This study was undertaken to determine the caloric intake required to maintain weight in patients under 12 years of age with burns over more than 30% total body surface area. The 102 patients studied were divided into two groups according to weight changes. A comparison of the actual caloric intakes of these groups was conducted. Multivariate regression analysis indicated that body surface area in square meters and burn surface were significant predictors of caloric requirements to maintain weight in these patients. It was determined that 1800 kcal was a plausible value for the calories per body surface area. Therefore the regression was formed with 1800 kcal as the multiplier of body surface area, and the multiplier of burn surface area was estimated. The resulting formula provides 1300 kcal/m2 burned, which is 900 kcal/m2 burned less than our previously suggested formula.
Assuntos
Peso Corporal , Queimaduras/dietoterapia , Ingestão de Energia , Superfície Corporal , Queimaduras/metabolismo , Criança , Pré-Escolar , Nutrição Enteral , Humanos , Lactente , Estado NutricionalRESUMO
New formulas for estimating the caloric requirements of burned children have been suggested. These formulas appeared to exceed the caloric estimates made by the Galveston Shriners Burns Institute formula. This study was undertaken to compare the Curreri Junior formulas and the Galveston Shriners Burns Institute formula with the actual intake required by pediatric patients with burns greater than 30% total body surface area to maintain weight. The 121 patients studied were divided into three age groups to coincide with those in the Curreri Junior formulas and calorie requirements as estimated by both formulas were determined. The comparison of these estimations with the actual intake required to maintain weight indicated that there is a significant difference in the caloric requirement per m2 burn between the age three and under group and the older age group. The results also suggest that overfeeding may occur with the historic formulas.
Assuntos
Queimaduras/terapia , Ingestão de Energia , Nutrição Enteral , Alimentos Formulados , Peso Corporal , Criança , Fenômenos Fisiológicos da Nutrição Infantil , Pré-Escolar , Humanos , Lactente , Necessidades NutricionaisRESUMO
Nutritional support is provided to children after severe burn injuries in amounts derived from empirical formulas or measurements of resting energy expenditure. To scrutinize these methods, indirect calorimetry measurements were performed on 74 survivors of burns (greater than or equal to 40% total body surface area) and compared to their actual caloric intake, percent weight change, and optimal caloric requirements formulated from the Curreri and Shriners' equations. These parameters showed that in spite of an initial deficit in actual caloric intake as compared to formulated goals, weight was maintained, whereas resting energy expenditures ranged from 30% to 40% below the actual caloric intake. Furthermore, a subgroup of patients (n = 42) who met +/- 20% of their formulated needs were stratified by extent of burn; this illustrated a significant weight gain in the more severely burned children. In conclusion, nutritional formulas in popular use overestimate caloric requirements in severe burns, whereas resting energy expenditure measurements require an additional factor of 30% to maintain body weight.
Assuntos
Queimaduras/metabolismo , Ingestão de Energia , Metabolismo Energético , Peso Corporal , Queimaduras/dietoterapia , Criança , Alimentos Formulados , Humanos , Aumento de PesoRESUMO
Formulas for estimating the caloric requirements of pediatric and adult patients with burns have been suggested. However, the needs of adolescent patients with burns have not been specifically addressed. This study was undertaken to determine the calorie intake required to maintain weight of adolescent patients with burns over more than 35% of the total body surface area. The 29 patients studied were divided into two groups according to sex. Caloric requirements were determined with the use of the Galveston surface area formula and the Curreri formula. The comparison of these estimations with the actual intake required to maintain weight indicated that there is a significant difference between the calories indicated by the formulas and the actual intake. A surface area formula that also correlates with the results of indirect-calorimetry studies is suggested for this adolescent population with burns.
Assuntos
Queimaduras/terapia , Ingestão de Energia , Necessidades Nutricionais , Adolescente , Superfície Corporal , Peso Corporal , Calorimetria Indireta , Feminino , Humanos , MasculinoRESUMO
Formulas for estimating the caloric requirements of pediatric patients with burns have been suggested. However, the needs of infant patients with burns have not been specifically addressed. This study was undertaken to determine the caloric intake required to maintain weight in patients under 1 year of age who had burns covering more than 25% total body surface area. Thirty patients were studied, and a comparison was made between the actual intake required for weight maintenance and the suggested calorie levels provided by published pediatric caloric formulas. The results indicated that a new formula was needed. Multivariate regression analysis indicated that body surface area and burn surface area were significant predictors of caloric requirements, but body surface area was the more important predictor in this infant population. The equation resulting from the regression provides 2100 kcal/m2 body surface area/day plus 1000 kcal/m2 body surface area burned/day.
Assuntos
Queimaduras/metabolismo , Fatores Etários , Temperatura Corporal , Peso Corporal , Queimaduras/terapia , Metabolismo Energético , Feminino , Humanos , Lactente , Alimentos Infantis , Tempo de Internação , MasculinoRESUMO
OBJECTIVE: To evaluate effectiveness of an allicin-based product in neonatal calves inoculated with Cryptosporidium parvum. DESIGN: Randomized controlled study. ANIMALS: 43 neonatal calves. PROCEDURE: Calves were inoculated with 1.5 x 10(8) or 7.5 x 10(5) C parvum oocysts within 2 days after birth. Calves were given an allicin-based product once after inoculation or daily for 7 days after inoculation or were not treated. Calves that developed diarrhea were treated by administration of the product. Fecal consistency scores and weight gains were statistically evaluated. RESULTS: Mean daily weight gain and severity of diarrhea in calves 4 to 21 days old were unaffected by prophylactic use of the product. However, intensive prophylactic administration may have delayed onset of C parvum-induced diarrhea in calves inoculated with the lower dose of oocysts. CLINICAL IMPLICATIONS: Administration of an allicin-based product did not alter duration of C parvum-induced diarrhea or enhance weight gain in neonatal calves. However, intensive prophylactic administration of an allicin-based product may delay onset of diarrhea in calves exposed to C parvum oocysts.
Assuntos
Anti-Infecciosos/uso terapêutico , Doenças dos Bovinos/tratamento farmacológico , Criptosporidiose/veterinária , Cryptosporidium parvum , Ácidos Sulfínicos/uso terapêutico , Animais , Animais Recém-Nascidos , Bovinos , Criptosporidiose/tratamento farmacológico , Diarreia/tratamento farmacológico , Diarreia/veterinária , Dissulfetos , MasculinoRESUMO
α-Santalol is active component of sandalwood oil and has been shown to have chemopreventive effects against chemically and UVB-induced skin cancer development in mice. α-Santalol is also shown to have skin permeation enhancing effects. Honokiol and magnolol isolated from Magnolia officinalis bark extract have also been shown to have chemopreventive effects against chemically and UVB-induced skin cancer in mice. This study was conducted to investigate the combination effects of α-santalol, honokiol and magnolol to study any additive/synergistic effects to lower the doses required for chemoprevention. Pretreatment of combinations of α-santalol with honokiol and magnolol significantly decreased tumor multiplicity upto 75% than control, α-santalol, honokiol and magnolol alone in SKH-1 mice. Combination of α-santalol with honokiol and magnolol also decreased cell viability, proliferation, and enhanced apotosis in comparison to α-santalol, honokiol and magnolol alone in Human epidrmoid carcinoma A431 cells. Overall, the results of present study indicated combinations of α-santalol with honokiol and magnolol could provide chemoprevention of skin cancer at lower doses than given alone.
Assuntos
Anticarcinógenos/administração & dosagem , Compostos de Bifenilo/administração & dosagem , Lignanas/administração & dosagem , Sesquiterpenos/administração & dosagem , Neoplasias Cutâneas/prevenção & controle , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quimioterapia Combinada , Feminino , Camundongos , Neoplasias Induzidas por Radiação/prevenção & controle , Sesquiterpenos Policíclicos , Neoplasias Cutâneas/etiologia , Raios UltravioletaRESUMO
Haemonchus contortus infections have been increasingly reported in ungulates from cold climates even though past studies have shown that the free-living juveniles from this species survive poorly under freezing conditions. Overwintering strategies of H. contortus have not been documented in the Unites States Northern Great Plains. A PCR survey identified H. contortus as vastly predominant trichostrongyle species present (in addition to occasional detections of Teladorsagia sp.) in a closed farm flock of sheep from Brookings County, SD. Benzimidazole (BZ) and avermectin (AV) anthelmintics had been used intensely for many years on this flock. During the autumn season, three fecal egg count reduction tests (doramectin, albendazole, and moxidectin) were performed over a 4 year span to assess drug effectiveness within the flock. Significant drug resistance was found in Haemonchus adults with doramectin (69% efficacy), marginal resistance was found with albendazole (90% efficacy) and no resistance was found in moxidectin (100% efficacy). The following spring, pre-lambing and post-lambing fecals were obtained from albendazole and moxidectin treatment years to assess the resistance of the tissue-dwelling fourth-stage juveniles (J4s) at those times. Albendazole treated pre-lambing fecals averaged only 4 EPG and treated post-lambing fecals increased to 454 EPG, indicating that many of the J4s were not killed during the autumn treatment. Moxidectin pre-lambing fecals averaged only 1 EPG, and post-lambing fecals only increased to 6 EPG in the treated moxidectin population and 1422 EPG in the untreated moxidectin population. In addition to evaluating the ability of H. contortus to overwinter as drug resistant tissue-dwelling J4s, this study also evaluated the overwintering ability of pasture-dwelling, free-living third-stage juveniles at this farm. In the summers of 2010 and 2011, naïve tracer lambs were placed on a H. contortus contaminated pasture for 3 weeks to assess J3 winter survival. In 2010, tracer lambs only averaged 7 EPG whereas drylotted control lambs averaged 2 EPG; in 2011, tracer lambs averaged 2 EPG while the control lambs averaged 1 EPG. These results suggest that at this northern plains farm, yearly transmission of H. contortus is predominately through drug-resistant J4s. This is consistent with other cold-climate, overwintering studies involving H. contortus from Europe.