Impact Of Mites Research Articles

Microscopic Menaces: The Impact of Mites on Human Health.

Mites are highly prevalent arthropods that infest diverse ecological niches globally. Approximately 55,000 species of mites have been identified but many more are yet to be discovered. Of the ones we do know about, most go unnoticed by humans and animals. However, there are several species from the Acariformes superorder that exert a significant impact on global human health. House dust mites are a major source of inhaled allergens, affecting 10-20% of the world's population; storage mites also cause a significant allergy in susceptible individuals; chiggers are the sole vectors for the bacterium that causes scrub typhus; Demodex mites are part of the normal microfauna of humans and their pets, but under certain conditions populations grow out of control and affect the integrity of the integumentary system; and scabies mites cause one of the most common dermatological diseases worldwide. On the other hand, recent genome sequences of mites provide novel tools for mite control and the development of new biomaterial with applications in biomedicine. Despite the palpable disease burden, mites remain understudied in parasitological research. By better understanding mite biology and disease processes, researchers can identify new ways to diagnose, manage, and prevent common mite-induced afflictions. This knowledge can lead to improved clinical outcomes and reduced disease burden from these remarkably widespread yet understudied creatures.

Parasitic mites alter chicken behaviour and negatively impact animal welfare

The northern fowl mite, Ornithonyssus sylviarum, is one of the most common and damaging ectoparasites of poultry. As an obligate blood feeding mite, the northern fowl mite can cause anaemia, slower growth, and decreased egg production of parasitized birds. However, the impact of mites or other ectoparasites on hen behaviour or welfare is not well studied. Here, we use activity sensors (three-axis accelerometers) affixed to individual birds to continuously record hen movement before, during, and after infestation with mites. Movements recorded by sensors were identified to specific bird behaviours through a previously trained algorithm, with frequency of these behaviours recorded for individual birds. Hen welfare was also determined before, during, and after mite infestation of hens using animal-based welfare metrics. Northern fowl mites significantly increased hen preening behaviour and resulted in increased skin lesions of infested birds.

Imaging coprolite taphonomy and preservation

The impact of coprolite taphonomy on parasite remains and aDNA recovery has been recognized. In general, coprolites from sites protected by geologic features such as caves and rock shelters exhibit the best preservation. In contrast, coprolites from open sites can be badly affected by taphonomic processes as shown by analyses of parasite eggs. For eggs, the impact of mites and free-living nematodes has been quantified. Mites are associated with poor pinworm egg preservation. In other studies, percolation of water through sediments has a negative impact on egg recovery. We note that dietary remains can also decompose at open sites. Through scanning electron microscopy (SEM), we present examples of screened but chemically untreated microscopic remains. “Panorama” SEM images provide an excellent visual overview of the taphonomy of dietary remains. For this study, our focus is on Southwestern coprolites as a demonstration of diversity within a single region. Examples from caves and rock shelters were examined first to describe the taphonomic challenges for protected sites. Then, attention was turned to coprolites from open sites. In general, the challenges noted for parasite preservation are seen for other microfossils. However, the preservation of lignin, sporopollenin, calcium oxalate, and siliceous microfossils is generally better than cellulose structures. These observations are relevant to the selection process of samples for aDNA analysis and immunological study. This is especially relevant for the gut microbiome since decomposer fungi and bacteria molecular signals could be recovered in metagenomic analysis.

Host-plant variety and not climate determines the establishment and performance of Aceria lantanae (Eriophyidae), a biological control agent of Lantana camara in South Africa.

The flower-galling mite Aceria lantanae (Cook) (Trombidiformes: Eriophyidae) was released for the biological control of Lantana camara L. (Verbenaceae) in South Africa in 2007, but has displayed variable and patchy establishment throughout the weed's range. Surveys were undertaken in 2013-2014, both seasonally and during the mite's peak infestation periods, to determine the influence of climatic factors on its performance. Although there were seasonal differences in the percentages of mite-infested inflorescences, these did not differ significantly between altitudinal zones. There were also no significant relationships between the percentages of mite-infested inflorescences and either of annual rainfall, temperature or relative humidity. A field inoculation trial revealed significant differences between 10 common South African L. camara varieties in their susceptibility to A. lantanae. Only three varieties displayed appreciable susceptibility (50-61% of inflorescences infested), whereas six displayed only slight to moderate susceptibility (8-21%) and one displayed a lack of susceptibility (no infestation). These data support the contention that differential varietal susceptibility and not climate is responsible for the variable performance of A. lantanae on L. camara in South Africa. Complementing the current biotype of A. lantanae, originally sourced from Florida (USA), with other biotypes from different L. camara genotypes in Central and South America could increase the mite's impact on the weed.

The Effect of Hummingbird Flower Mites on Nectar Availability of Two Sympatric Heliconia Species in a Brazilian Atlantic Forest

Hummingbird flower mites feed and reproduce in flowers of host plants pollinated by hummingbirds, and use the nostrils and bill of the hummingbird to move from plant to plant. These mites compete with the pollinator for the nectar produced by flowers. An investigation was made of the relationship between the pattern of nectar production and the effects of hummingbird flower mites in the flowers of two sympatric species of Heliconia (Heliconiaceae). Nectar production was sampled by carrying out two experiments: 2-hour intervals and accumulated nectar. Flowers with and without mites were used in both experiments. Exclusion of mites increased nectar production, especially in accumulated daily production (a maximum of 49 % more nectar). Both Heliconia species had the same pattern of nectar production: a high concentration in the morning, which was progressively reduced as the day passed. This pattern of nectar production coincides with the behaviour of the pollinator, which makes more frequent visits in the morning, as observed in a previous study. The results suggest that the impact of mites on nectar availability of Heliconia is more important with regard to total volume of nectar produced irrespective of flower longevity. A high variation among individuals in nectar produced in the populations was also observed. Hummingbird flower mites strongly affect availability of nectar for hummingbirds.

Impact and management of the eriophyoid mite Trisetacus juniperinus on the evergreen cypress Cupressus sempervirens

Abstract 1 In the Mediterranean region, the eriophyoid mite Trisetacus juniperinus causes considerable damage to the evergreen cypress, Cupressus sempervirens L., particularly in nurseries and young stands, disturbing the apical growth of the tree.2 The impact of mites on survival and apical growth of two commercial clones of cypress (Agrimed and Bolgheri), as well as the results of differently timed pesticide applications to suppress mite population on newly grafted trees, were evaluated.3 Mites easily infested clonal scions from rootstocks that were previously infested in the nursery, inducing tip deformation and disturbance of the growth. Apical growth was significantly lower in infested than in control trees 2 years following the graft.4 Deformed apical buds were left early by mites, which dispersed in the crown and may have incurred high mortality. This is interpreted as a defensive reaction of the cypress to the mite attack, which involves costs resulting in reduced apical growth in both clones. However, mites partly overcame tree defences in the Bolgheri clone.5 Healthy rootstock and graft material should be used to limit damage and maintain plant growth because natural infestations rarely occur. In case of attack, a pesticide should be applied as soon as possible because precocious mite infestation has a log‐lasting effect on tree growth, with considerable economic damage.

Impact of Mites and Miticides on the Photosynthetic Biology of Strawberry and Red Raspberry Leaves

Limited twospotted spider mite feeding significantly reduced the CO2 assimilation rate of red raspberry leaves and damaged the photosynthetic apparatus prior to visible damage to the leaf. The impact of miticides on the photosynthetic biology of raspberry and strawberry leaves was tested in growth chambers, greenhouses, and the field, with similar results across environments. In general, miticides appear to reduce the photosynthetic capacity of the leaves for 10 to 14 days, with reductions of ≈30% occurring within the first several days. Chlorophyll fluorescence and fourth-derivative spectroscopy of intact leaf lamina showed changes in the structure and function of the photosynthetic apparatus in response to chemical treatment. High temperature reduced physiological processes in strawberry plants grown at two diurnal regimes (30/24C, 21/15C); however, the relative degree of reduction in photosynthetic activity due to miticide application was similar for both. A preliminary screening of mite-resistant and -susceptible red raspberry genotypes after prolonged infestation suggested varying levels of physiological tolerance of mite damage, which are not well-correlated with visual appearance.