| age structure of horn fly (diptera: muscidae) populations estimated by pterin concentrations. | pterins accumulate in the head capsules of horn flies, haematobia irritans irritans (l.), as a linear function of time and temperature. pterin concentrations were used to estimate chronological ages and to establish correlations between chronological age and ovarian development and reproductive success in 12 horn fly populations in 1988 and 1989. male ages were estimated spectrofluorometrically. there were statistically significant differences between years in population age structure measured b ... | 1992 | 1495079 |
| interactive response of the horn fly (diptera: muscidae) and selected breeds of beef cattle. | statistically significant differences were observed in the population density of the horn fly, haematobia irritans irritans (l.), on different breeds of beef cattle. the european breed chianina had a population density of horn flies generally less than or equal to 50% than that of the british cattle breeds (angus, hereford, polled hereford, and red poll) and another european breed (charolais). generally, no significant difference existed among numbers of horn flies on hereford, polled hereford, ... | 1991 | 1842801 |
| antibody responses in cattle infested with haematobia irritans irritans (diptera: muscidae). | antibody response to feeding by the horn fly, haematobia irritans irritans (l.), was measured in naturally infested cattle as well as in controlled infestations. humoral antibody level was not correlated with fly abundance in natural infestations. correlations between the antibody response and fly abundance were extremely variable among animals. antibody response to horn fly salivary antigens peaked within 4 wk after fly abundance reached 150 flies per animal. in controlled infestations, antibod ... | 1995 | 7473617 |
| insecticides and acaricides: resistance and environmental impact. | insecticides continue to be the primary means of control for ectoparasites on livestock. intensive use of these materials has led to resistance to organochlorines, organophosphates and pyrethroids among populations of haematobia irritans irritans, h. irritans exigua and lucilia cuprina. similarly, use of acaricides has led to resistance in one-host boophilus ticks to all currently-used organophosphate-carbamates, synthetic pyrethroids and amidines. resistance in multi-host ticks is less widespre ... | 1994 | 7711312 |
| efficacy of brahman breeding in the management of insecticide-resistant horn flies (diptera: muscidae) on beef cattle. | the efficacy of brahman breeding used as an alternative tactic to manage insecticide-resistant populations of adult horn flies, haematobia irritans irritans (l.), was determined. concentration-mortality bioassays done at booneville and hope, ar, in 1988 and 1989, respectively, showed that horn fly populations were resistant to diazinon, pirimiphos methyl, tetrachlorvinphos, and methoxychlor. data showed loss of field efficacy for coumaphos and delnav. mean horn fly counts on braham cows were sig ... | 1994 | 8144749 |
| cloning, sequencing, and characterization of a complementary dna from haematobia irritans irritans (diptera: muscidae) that shares significant homology to a yeast atpase. | a study of the molecular genetics of the horn fly, haematobia irritans irritans (l.), has resulted in the isolation and sequencing of a 2316-bp complementary dna (cdna) clone, hfn2b. an open reading frame was found, the deduced 464 amino acid sequence of which encodes a protein with 40% identity to afg1, a member of a yeast family of atpases; it contains an atp- or gtp-binding p-loop motif. northern and southern blot analyses do not reveal significant differences in the expression of the gene ho ... | 1995 | 8551518 |
| the effects of selection for size in cattle on horn fly population density. | statistically significant differences were observed in the population density of the horn fly, haematobia irritans irritans l., on angus cows having significantly different frame sizes. angus cows, averaging < 112.5 cm in height at the hip, had significantly lower numbers of horn flies than angus cows that measured 112.5-117.5 cm, 117.5-120 cm, 120-126 cm and > 126 cm in height at the hip. the angus i cows ( < 112.5 cm in height at the hip) were significantly shorter in length (mean distance fro ... | 1996 | 8744704 |
| screening of haematobia irritans irritans (diptera: muscidae) populations for pyrethroid resistance-associated sodium channel gene mutations by using a polymerase chain reaction assay. | a polymerase chain reaction (pcr)-based rapid screening procedure was developed to test individual horn flies, haematobia irritans irritans (l.), for the presence of a specific nucleotide substitution in the sodium channel gene sequence that has been associated with pyrethroid resistance. by a systematic optimization of reaction conditions and judicious choice of pcr primers differing in dna sequence by a single nucleotide, we identified pyrethroid-susceptible or resistant sodium channel alleles ... | 1998 | 9775598 |
| survival, ovarian development and bloodmeal size for the horn fly haematobia irritans irritans reared in vitro. | horn flies, haematobia irritans irritans (linneaus) (diptera: muscidae) were reared in vitro using cattle, pig, horse, rabbit, sheep, goat or chicken blood. the highest survival, bloodmeal size and rate of ovarian development were recorded for both female and male flies fed cattle blood. flies fed pig, rabbit, sheep and goat blood showed intermediate survival. flies fed chicken blood showed the lowest survival rates, ingested the smallest bloodmeals and did not develop ovaries. the relationship ... | 2000 | 10872865 |
| bovine teat atresia associated with horn fly (haematobia irritans irritans (l.))-induced dermatitis. | mammary gland lesions characterized primarily as mammary teat atresia were observed in a limousin beef cattle herd in eastern texas. atresia of multiple teats per mammary gland was reported in first-calf heifers at the time of calving. pathogens were not identified in eight mammary glands collected at slaughter. histology of affected glands demonstrated superficial and deep perivascular inflammation and fibrosing dermatitis of teat and mammary gland skin that resulted in formation of the atretic ... | 2000 | 10896402 |
| purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of horn fly, haematobia irritans irritans (diptera: muscidae). | this work describes the purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of haematobia irritans irritans (diptera: muscidae). the enzyme was purified using a one-step process, consisting of affinity chromatography on sbti-sepharose. the purified protease showed one major active proteinase band on reverse zymography with 0.15% gelatin, corresponding to a molecular mass of 25.5 kda, with maximum activity at ph 9.0. the purified trypsin-li ... | 2000 | 11195976 |
| dynamics of haematobia irritans irritans (diptera: muscidae) infestation on nelore cattle in the pantanal, brazil. | from june 1993 to may 1995, horn fly counts were conducted twice a month on untreated nelore cattle raised extensively in the pantanal. horn fly population showed a bimodal fluctuation and peaks were observed every year after the beginning (november/december) and at the end (may/june) of the rainy season, which coincided with mid-late spring and mid-late fall, respectively. horn flies were present on cattle throughout the year in at least 64% of the animals. mean horn fly numbers on animals did ... | 2001 | 11391414 |
| comparison of two methods (visual estimates and filming) for counts of horn flies (haematobia irritans irritans) (l.) (diptera: muscidae). | visual estimates are generally used for counts of horn flies, haematobia irritans (l.) and play an important role as an instrument to quantify fly populations in scientific studies. in this study, horn fly counts were performed on 30 nelore steers in the municipality of araçatuba, sp brazil, from january to december 1998. flies were counted weekly by two methods: the estimate method whereby estimates of the number of flies on one side of the animal are obtained by visual observation, and the fil ... | 2002 | 11750116 |
| use of the polymerase chain reaction to investigate the dynamics of pyrethroid resistance in haematobia irritans irritans (diptera: muscidae). | a field study was conducted from 1991 through 1997 to evaluate the use of pyrethroid and organophosphate (op) ear tags, alternated yearly, for the control of a pyrethroid resistant horn fly, haematobia irritans (l.), population in louisiana. fly resistance was monitored by weekly fly counts, filter paper bioassays and diagnostic polymerase chain reaction (pcr) assays for the presence of pyrethroid resistance-associated mutations in the sodium channel gene coding region. fly control in the first ... | 2002 | 12349858 |
| variation in population density of horn flies (haematobia irritans irritans) (l.) (diptera: muscidae) in nellore cattle (bos indicus). | the population density of horn flies was evaluated in the year 1998 in the municipality of araçatuba, são paulo brazil, in relation to temperature and rainfall conditions. two lots of 30 nellore steers (bos indicus) were used which had no insecticidal treatment and were naturally infested with horn flies. the infestations were assessed by two counting methods, i.e., the traditional estimate method and the filming method. the highest fly frequencies were recorded in spring, summer, autumn and the ... | 2003 | 14637033 |
| survey of resistance to permethrin and diazinon and the use of a multiplex polymerase chain reaction assay to detect resistance alleles in the horn fly, haematobia irritans irritans (l.). | a field survey was conducted in 2001 to evaluate resistance to pyrethroid and organophosphate (op) insecticides on horn flies, hematobia irritans irritans (l.), from seven ranches in the state of tamaulipas, mexico, and from three locations in central texas. filter papers impregnated with either technical permethrin or diazinon were used to measure the levels of resistance to pyrethroids and ops. a multiplex polymerase chain reaction (pcr) assay was used on individual horn flies from these field ... | 2003 | 14765674 |
| evaluation of a recombinant salivary gland protein (thrombostasin) as a vaccine candidate to disrupt blood-feeding by horn flies. | the potential for controlling blood-feeding by the cattle pest, haematobia irritans irritans (horn fly), was tested by vaccination against thrombostasin (ts), an inhibitor of mammalian thrombin that is released into skin during horn fly blood-feeding. the increase in blood meal size that occurred for flies feeding on sensitized non-vaccinated hosts was blocked and egg development in female flies was delayed when horn flies fed on rabbits and cattle immunized with recombinant ts. this demonstrati ... | 2004 | 15149788 |
| purification, characterization, and cloning of a serine proteinase inhibitor from the ectoparasite haematobia irritans irritans (diptera: muscidae). | the fly haematobia irritans irritans is one of the most important ectoparasites in cattle production, due to its ability to suck large amounts of blood. this report describes the purification and characterization of a serine proteinase inhibitor (hiti) present in h. i. irritans head and thorax extracts. the hiti purified by affinity chromatography on trypsin-sepharose has a molecular mass of 7029da by maldi-tof mass spectrometry. hiti inhibited bovine trypsin, human neutrophil elastase, and a tr ... | 2004 | 15172217 |
| association of the kdr and superkdr sodium channel mutations with resistance to pyrethroids in louisiana populations of the horn fly, haematobia irritans irritans (l.). | pyrethroid resistance in three horn fly populations in louisiana was monitored by weekly fly counts, filter paper bioassays, and diagnostic pcr assays for the presence of pyrethroid resistance-associated mutations in the sodium channel gene coding region. the pcr assay for the knockdown resistance (kdr) and superkdr sodium channel mutations was used to determine the frequency of the target site insensitivity mechanism in the populations of horn flies, which possessed varying degrees of insectici ... | 2005 | 15817215 |
| validation of a subjective counting method for a horn flies (haematobia irritans irritans) (diptera: muscidae) population in a cattle herd. | a trained observer direct count method to measure horn fly population was evaluated to determine the reliability (inter-observer agreement) and its validity when compared with a "gold standard" method (video film). all the counts were performed with the animals restrained in a chute in a single herd. a direct count of horn flies by each of two observers on opposite sides of the animal was made. in addition a videotape recording of the counting surface on each animal was made. horn flies were cou ... | 2005 | 16011876 |
| the role of hiti, a serine protease inhibitor from haematobia irritans irritans (diptera: muscidae) in the control of fly and bacterial proteases. | blood-sucking arthropods are vectors responsible for the transmission of several pathogens and parasites to vertebrate animals. the horn fly haematobia irritans irritans (diptera: muscidae) and the tick boophilus microplus are important hematophagous ectoparasites that cause losses in cattle production. a serine protease inhibitor from a thorax extract of the fly h. irritans irritans (hiti) was previously isolated, characterized and cloned. in the present study we described the expression, purif ... | 2005 | 16054488 |
| role of kdr and esterase-mediated metabolism in pyrethroid-resistant populations of haematobia irritans irritans (diptera: muscidae) in brazil. | the horn fly, haematobia irritans irritans (l.) (diptera: muscidae), has become a problem for brazilian cattle producers even though its introduction into brazil is relatively recent. failure to control this cattle pest is becoming a concern, and horn fly populations from several ranches from the state of mato grosso do sul were surveyed for pyrethroid resistance. susceptibility bioassays revealed that cypermethrin resistance was widespread and reached high levels in horn fly populations through ... | 2006 | 17017226 |
| does gender really matter in contaminant exposure? a case study using invertebrate models. | exposure to contaminants in the environment is indiscriminate and multiple species/populations of all sexes are potentially at risk. in this paper we examine the current information available on gender specific differences in invertebrates following exposure to environmental contaminants. because of their close association with the environment and diversity of habitats, invertebrates are uniquely at risk for adverse responses to pollutants. since 97% of all animal species are invertebrates, it w ... | 2007 | 17097631 |
| population dynamics of horn fly, haematobia irritans irritans (l.) (diptera: muscidae), on hereford cattle in uruguay. | abundance of adult horn flies, haematobia irritans irritans (l.), was monitored on 25 untreated hereford cows in tacuarembó department, uruguay, during three consecutive grazing seasons, from october 1999 to may 2002. the population showed a variable pattern of abundance during three years, with peaks in late summer-early fall of each year. adult flies were continuously present, although in very low numbers in intervening winters. numbers of flies per cow rarely exceeded a reference level of 200 ... | 2008 | 18093739 |
| validation of phage display method for protease inhibitor selection using synthetic hybrid peptides. | a recombinant haematobia irritans irritans trypsin inhibitor (hiti - mw 7030 kda)) phagemid library was constructed and displayed functionally on the tip of the filamentous m13 phage. a combinatorial library of 7.2 x 10(6) mutants was created with hiti mutations restricted to the p1'-p3' and p5' positions of the reactive site. this combinatorial library was selected for trypsin-like pr2 proteases of metarhizium anisopliae fungus, and 11 hiti mutants containing the following substitutions: k17g, ... | 2010 | 20615196 |
| molecular characterization and immunolocalization of the olfactory co-receptor orco from two blood-feeding muscid flies, the stable fly (stomoxys calcitrans, l.) and the horn fly (haematobia irritans irritans, l.). | biting flies are economically important blood-feeding pests of medical and veterinary significance. chemosensory-based biting fly behaviours, such as host/nutrient source localization and ovipositional site selection, are intriguing targets for the development of supplemental control strategies. in an effort to expand our understanding of biting fly chemosensory pathways, transcripts encoding the highly conserved insect odorant co-receptor (orco) were isolated from two representative biting fly ... | 2013 | 23278866 |
| survival and fate of salmonella enterica serovar montevideo in adult horn flies (diptera: muscidae). | contamination of cattle peripheral lymph nodes with salmonella enterica is proposed to occur via a transdermal route of entry. if so, bacteria may be introduced to cattle by biting arthropods. biting flies, such as horn flies (haematobia irritans irritans (l.)) (diptera: muscidae), are intriguing candidates for transmitting salmonella to cattle because they provide a route of entry when they breach the skin barrier during blood feeding. using a green fluorescent protein-expressing strain of salm ... | 2014 | 25276929 |
| discovery of the rdl mutation in association with a cyclodiene resistant population of horn flies, haematobia irritans (diptera: muscidae). | the horn fly, haematobia irritans irritans, is an obligate blood-feeding parasite of cattle that causes significant economic impact in many countries. we investigated the resistance of a horn fly population from louisiana/usa to endosulfan, a cyclodiene insecticide. bioassays were performed in 2010 and 2011 in order to determine the resistance ratio of the population to endosulfan and a pcr assay was developed to detect the rdl mutation which is the replacement of an alanine with a serine at the ... | 2013 | 24055107 |
| effects of the botanical compound p-anisaldehyde on horn fly (diptera: muscidae) repellency, mortality, and reproduction. | the horn fly, haematobia irritans irritans (l.) (diptera: muscidae), is an economically important obligate blood feeder that mainly attacks cattle in europe, asia, and north and south america. as horn fly resistance to conventional insecticides becomes more common, alternative control tactics, such as application of bioactive botanical natural products are being investigated. p-anisaldehyde has been found in many plant species, and it has shown effects that include mortality, attractancy, and in ... | 2018 | 29029251 |
| simultaneous detection of pyrethroid, organophosphate, and cyclodiene target site resistance in haematobia irritans (diptera: muscidae) by multiplex polymerase chain reaction. | the horn fly, haematobia irritans irritans (l., 1758) (diptera: muscidae), is an important pest that causes significant economic losses to the livestock industry, but insecticide resistance in horn fly populations has made horn fly control increasingly difficult to achieve. in this study, we developed a multiplex polymerase chain reaction (pcr) assay to simultaneously detect target site resistance to pyrethroids (kdr mutation), organophosphates (g262a acetylcholinesterase mutation), and cyclodie ... | 2014 | 25276924 |
| susceptibility of the horn fly, haematobia irritans irritans (diptera: muscidae), to insecticides in brazil. | since horn fly populations became established throughout brazil, complaints regarding control failure have increased around the country. a broad survey to evaluate the susceptibility of horn flies to both organophosphate (op) and pyrethroid insecticides was conducted from october 2000 to april 2003. bioassays using filter papers impregnated with cypermethrin, permethrin or diazinon were conducted on 154 horn fly populations in 14 states and 78 municipalities. resistance to cypermethrin, the acti ... | 2013 | 22832752 |