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The current study examined the impact of ultraviolet (UV)‐B radiation in Metarhizium pingshaense blastospores' photolyase expression and their virulence against Rhipicephalus microplus. Blastospores were exposed to UV under laboratory and field conditions. Ticks were treated topically with fungal suspension and exposed to UV‐B in the laboratory for three consecutive days. The expression of cyclobutane pyrimidine dimmers (CPDs)‐photolyase gene maphr1‐2 in blastospores after UV exposure followed by white light exposure was accessed after 0, 8, 12, 24, 36, and 48 h. Average relative germination of blastospores 24 h after in vitro UV exposure was 8.4% lower than 48 h. Despite this, the relative germination of blastospores exposed to UV in the field 18 h (95.7 ± 0.3%) and 28 h (97.3 ± 0.8%) after exposure were not different (p > 0.05). Ticks treated with fungus and not exposed to UV exhibited 0% survival 10 days after the treatment, while fungus‐treated ticks exposed to UV exhibited 50 ± 11.2% survival. Expression levels of maphr1‐2 8, 12, and 24 h after UV‐B exposure were not different from time zero. Maphr1‐2 expression peak in M. pingshaense blastospores occurred 36 h after UV‐B exposure, in the proposed conditions and times analyzed, suggesting repair mechanisms other than CPD‐mediated‐photoreactivation might be leading blastospores' germination from 0 to 24 h. [ABSTRACT FROM AUTHOR]

BACKGROUND: The control of ticks is challenged by the resistance of tick populations to chemical acaricides. In this study, we evaluated, under laboratory conditions, the efficacy of Heterorhabditis bacteriophora against Rhipicephalus (Boophilus) microplus engorged females with varying body weights (150, 200, 250, 300 or 350 mg per female) or from eight different geographical populations. We also determined the efficacy of H. bacteriophora for tick control under field conditions. RESULTS: R. microplus engorged females with varying body weights exposed to 150 juveniles of H. bacteriophora resulted in a high control efficacy (97.5% to 98.4%). Tests with females from different geographical populations comprised eight tick strains treated with H. bacteriophora and their respective control groups. The biological parameters of females exposed to nematode treatments did not differ significantly and resulted in 89% to 99% of control efficacy. Trials conducted under field conditions were performed in field plots with Megathyrsus maximus grass. Treatment groups received eight cadavers of Tenebrio molitor fully colonized with H. bacteriophora at 1 week prior to the release of female ticks, whereas control groups were untreated. On the first day of the experiment, six engorged females were distributed in each plot. On day 42 and day 63, the apical portion of the grasses with R. microplus larvae were collected and quantified. The population of R. microplus larvae was reduced up to 73.1% in plots treated with H. bacteriophora at day 63 after treatment. CONCLUSION: R. microplus engorged females with varying body weights or from different geographical populations were highly susceptible to H. bacteriophora. The field test demonstrated the efficacy of H. bacteriophora in reducing R. microplus larvae in infested pastures. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background Epizootic bovine abortion ( EBA) is a tick-transmitted abortive disease of beef cattle in the western United States. Infected cattle do not have clinical signs until abortion occurs, usually within the last trimester of gestation. There is little information on the hematologic response of the dam following infection. Objective The purpose of this study was to determine if changes in blood leukocytes and serum IgG concentrations could be detected following experimental infection of pregnant heifers with the etiologic agent of EBA (ao EBA). Methods Twelve Angus heifers were infected during gestation with the ao EBA using an inoculum prepared from the thymus of an infected fetus. Five pregnant heifer controls were given an inoculum prepared from the thymus of an ao EBA-negative calf. PCVs, total and differential leukocyte counts, and serum IgG concentrations were measured weekly following administration of the inocula until abortion or calving. Gross and microscopic examinations were performed on all aborted fetuses to confirm infection. Results Eleven of 12 heifers in the treatment group aborted, and significant findings were decreased lymphocyte counts at weeks 1 and 14 postinoculation and increased monocyte counts at week 4 compared with control animals. Serum IgG concentrations were significantly increased at weeks 6-8 and 11 in the treatment group. Conclusions Leukogram changes are subtle in infected cattle. Future research efforts should be aimed at development of an antibody test specific for detection of previously infected animals, which could graze safely on EBA-endemic pastures. [ABSTRACT FROM AUTHOR]

Readily available information as to the management of arthropod bites, stings, and infestations is important to have but often difficult to find. This article brings such information together in one reference for use by the practicing pediatrician, dermatologist, and family practitioner. Preventive measures are stressed and therapy is outlined for each entity; the rationale for many of the interventions is discussed. It is not the intent of this paper to cover each subject comprehensively. [ABSTRACT FROM AUTHOR]

Provides information on several venomous arthropods. Evolution of stinging hymenoptera; Physiology of bee stings; Dermatological expression of a fire ant sting.