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At least 1,477 records · Page 82Linked to original sources
PubMed1993

Changes in malathion and pyrethroid resistance after cypermethrin selection of Culex quinquefasciatus field populations of Cuba.

Use of the organophosphorus insecticide malathion for mosquito control in Cuba, for 7 years up to 1986, selected elevated non-specific esterase and altered acetylcholinesterase (AChE) resistance mechanisms in Culex quinquefasciatus. In central Havana space-spraying of malathion was replaced by the pyrethroid cypermethrin in 1987: alternate cycles of malathion and cypermethrin were applied in some of the more rural areas of Havana district during 1987-91. Consequently, populations of Cx quinquefasciatus in the central area of Havana developed resistance to cypermethrin, but there is no evidence of pyrethroid resistance in the outlying areas. Malathion resistance levels declined significantly after 1986, measured both by bioassay and the frequency of the elevated esterase resistance mechanism, and then stabilized with no measurable decline during 1990 in any of the populations tested. These populations had less than 10% frequency of susceptible homozygotes for both the esterase and AChE resistance mechanisms, indicating that organophosphate resistance is still prevalent in Cuban Cx quinquefasciatus. These two mechanisms appear to be in linkage equilibrium, suggesting that current selection for double resistance is not strong. In the central Havana region, pirimiphos-methyl, an organophosphorus insecticide unaffected by the two common malathion resistance mechanisms, is now being used in a resistance management strategy designed to avoid pyrethroid resistance spreading.

Animals↗
PubMed2006

Behavioural responses of dairy cattle to the stable fly, Stomoxys calcitrans, in an open field environment.

Individual cows (25 in each of four herds) were monitored 8-10 times weekly for 12 weeks (stable fly season) on a southern California dairy, with 100 observations per cow. The numbers of biting stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae) on the front legs and the frequencies of four fly-repelling behaviours per 2-min observation period [head throws, front leg stamps, skin twitches (panniculus reflex) and tail flicks] were recorded. Fly numbers varied, peaking at 3.0-3.5 flies per leg in week 9 (late May). Weekly herd mean frequencies of fly-repelling behaviours were highly dependent on fly numbers, with a linear regression r(2) > 0.8. Head throws and stamps were less frequent than skin twitches and tail flicks. Individual cows differed in numbers of stable flies and behaviours. Behaviours were correlated with flies for individual cows, but at a lower level than were herd means (r = 0.3-0.7). Cows that stamped more within a herd tended to have lower fly counts; other fly-repelling behaviours were less effective. Cows maintained ranks within a herd with regard to fly numbers (r = 0.47), head throws (0.48), leg stamps (0.64), skin twitches (0.69) and tail flicks (0.64). Older cows tended to harbour higher fly numbers and to stamp less relative to younger adult cows. Ratios of leg stamps and head throws to fly numbers dropped significantly through time, suggesting habituation to pain associated with fly biting. Tail flicks were not effective for repelling Stomoxys, but were easiest to quantify and may help in monitoring pest intensity. At this low-moderate fly pressure, no consistent impacts on milk yield were detected, but methods incorporating cow behaviour are recommended for future studies of economic impact.

Analysis of Variance↗
PubMed2004

Diagnosis of flea allergy dermatitis: comparison of intradermal testing with flea allergens and a FcepsilonRI alpha-based IgE assay in response to flea control.

The objective of this study was to evaluate the accuracy of in vivo and in vitro tests in the diagnosis of flea allergy dermatitis in comparison with history, clinical signs and response to flea control. Intradermal testing using four different sources of flea allergens and FcepsilonRIalpha-based immunoglobulin (Ig)E assays were performed in 15 flea-allergic dogs, 15 atopic dogs and 15 dogs infested with fleas but showing no clinical signs of skin disease. Sensitivity, specificity, negative predictive value, positive predictive value and accuracy were calculated for all five tests and results varied greatly. Sensitivity, specificity and overall accuracy were 27, 83 and 64%, respectively, for one extract (Isotec), 67, 90 and 82% for another extract (Greer), 93, 90 and 91% for flea saliva, 40, 90 and 73% for the recombinant Cte f 1 both produced by Heska Corp. and 87, 53 and 64% for a FcepsilonRIalpha-based IgE assay. These results indicate that intradermal testing with flea extracts is more accurate in the diagnosis of flea allergy dermatitis than in vitro tests. Moreover, pure flea saliva used as a reagent for intradermal testing provided the best results in terms of sensitivity, specificity and overall accuracy although the Greer extract, a whole body flea extract, also allowed a good correlation between intradermal testing results and clinical approach to flea allergy dermatitis diagnosis.

Allergens↗
PubMed1995

The role of mast cells in treatment of scabies.

OBJECTIVE: The purpose of this study was to recognize the role of mast cells in the pathogenesis of scabies. METHODS: One hundred and fifty patients and 10 controls were included in the study. Group 1 included 20 patients without previous treatment. In group 2, 80 patients were treated with antiscabietic drugs. Group 3 had 50 patients who received an antiscabietic drug followed by 3 days of crotamiton. Diurnal and nocturnal skin biopsies were taken from group 1. In groups 2 and 3, the biopsies were taken after 2 weeks of treatment. Sections were cut and stained by hematoxylin and eosin and Giemsa stains. RESULTS: Mast cells were increased in diurnal and nocturnal biopsies. Evident degranulation of mast cells was detected in nocturnal biopsies. The mast cell number decreased to half its pretreatment number in patients treated with antiscabietic drugs and to its normal number in patients treated with antiscabietic drugs followed by 3 days with crotamiton. CONCLUSION: The number of mast cells are increased in scabietic lesions. This plays a role in the pathogenesis of the clinical and histologic picture of scabies. We recommend that an antiscabietic drug should be followed by 3 days of crotamiton in the treatment of scabies.

Administration, Cutaneous↗
PubMed1985

Variation in cutaneous sensation between synthetic pyrethroid insecticides.

Synthetic pyrethroids are potent insecticides, utilized for food protection and general pest control. Numerous investigations have indicated that ultra-low volume applications are effective and may eliminate the developing problem of resistance to the currently utilized insecticides. The most prominent health symptom that accompanies topical contact with these agents appears to be a cutaneous sensation, paresthesia. In this investigation, a substantial difference in the degree of paresthesia was noted between the formulated grade of 4 synthetic pyrethroids. Also, dl-alpha tocopheryl acetate was statistically validated as an efficacious therapeutic agent for cutaneous exposure to these insecticides.

Administration, Topical↗
PubMed2004

Flies and Helicobacter pylori infection.

Houseflies have been proposed to be a reservoir and vector for Helicobacter pylori. We assessed the effect of insecticide spraying in villages in The Gambia on H. pylori infection in young children. Effective control of flies did not prevent infection with H. pylori.

Animals↗
PubMed2005

Single blind, randomised, comparative study of the Bug Buster kit and over the counter pediculicide treatments against head lice in the United Kingdom.

OBJECTIVE: To compare the effectiveness of the Bug Buster kit with a single treatment of over the counter pediculicides for eliminating head lice. DESIGN: Single blind, multicentre, randomised, comparative clinical study. SETTING: Four counties in England and one county in Scotland. PARTICIPANTS: 133 young people aged 2-15 years with head louse infestation: 56 were allocated to the Bug Buster kit and 70 to pediculicide treatment. INTERVENTIONS: Home use of proprietary pediculicides (organophosphate or pyrethroid) or the Bug Buster kit. MAIN OUTCOME MEASURE: Presence of head lice 2-4 days after end of treatment: day 5 for the pediculicides and day 15 for the Bug Buster kit. RESULTS: The cure rate using the Bug Buster kit was significantly greater than that for the pediculicides (57% v 13%; relative risk 4.4, 95% confidence interval 2.3 to 8.5). Number needed to treat for the Bug Buster kit compared with the pediculicides was 2.26. CONCLUSION: The Bug Buster kit was the most effective over the counter treatment for head louse infestation in the community when compared with pediculicides.

Adolescent↗
PubMed1999

HIV associated eosinophilic folliculitis--differential diagnosis and management.

Eosinophilic folliculitis (EF) is a chronic, intensely pruritic condition of unknown pathogenesis that causes marked morbidity in those HIV patients whom it affects. There is a wide differential diagnosis of itchy skin conditions in HIV which are amenable to different treatments. It is therefore essential to take a biopsy of each suspected case and examine multiple sections of the biopsy to confirm or refute a diagnosis of EF. Treatment of EF can be difficult but we hope that by suggesting a rational approach to this and considering possible therapeutic options more patients may be helped with this troublesome dermatosis.

Administration, Topical↗