Acaroid mite, intestinal and urinary acariasis

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.

Regulation of three subtypes of SOD gene in Aleuroglyphus ovatus (Acari:Acaridae) under lead stress

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the mite antioxidant defense system, involved in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Nevertheless, the SOD gene family was yet to be reported in stored grain pest mite (Aleuroglyphus ovatus). In this study, A. ovatus was used to evaluate the response of SOD gene during lead stress. A. ovatus were separately exposed to different concentration lead (12.5, 25, 50, and 100 mg/kg), which induce the dynamic trend of SOD enzyme activity initially increased and then reduced with an increase in lead concentration, whereas they were still substantially higher than the control group. Moreover, after lead stress, it was found that all of the three SOD genes showed enhanced relative messenger RNA expression at high concentrations and decreased relative expression at low concentrations, which indicated that lead stress induces the expression of AoSODs. The present work implies that AoSODs play an important role in resisting oxidative damage caused by lead stress.

A lectin gene is involved in the defense of Pleurotus ostreatus against the mite predator Tyrophagus putrescentiae

The storage mite, Tyrophagus putrescentiae, found worldwide in many habitats, is an important pest of edible mushrooms. Excessive chemical spraying for pest control has been linked to environmental pollution, health risks, insecticide resistance development, and food safety. Host resistance can be sustainable and cost-effective and provide effective and economical pest control. Previous studies have reported that the oyster mushroom Pleurotus ostreatus has evolved effective defense mechanisms against T. putrescentiae attack, but the underlying mechanism remains unclear. Here we report that a lectin gene from P. ostreatus mycelia, Polec2, induced fungal resistance to mite grazing. Polec2 belongs to a galectin-like lectin classification, encoding a protein with β-sandwith-fold domain. Overexpression of Polec2 in P. ostreatus led to activation of the reactive oxygen species (ROS)/mitogen-activated protein kinases (MAPKs) signaling pathway, salicylic acid (SA), and jasmonate (JA) biosynthesis. The activation resulted in bursts of antioxidant activities of catalases (CAT), peroxidases (POD), superoxide dismutases (SOD), and increased production of SA, JA, jasmonic acid-isoleucine (JA-Ile) and jasmonic acid methyl ester (MeJA), accompanied by reduced T. putrescentiae feeding and suppressed its population. We also provide an overview of the phylogenetic distribution of lectins across 22 fungal genomes. Our findings shed light on the molecular mechanisms of P. ostreatus' defense against the mite predator and will be useful in investigating the molecular basis of fungi-fungivory interactions and gene mining for pest-resistance genes.

Effects of Long-Term Exposure to Cadmium on Development, Reproduction and Antioxidant Enzymes of Aleuroglyphus ovatus (Acari: Acaridae)

Grain contaminated by cadmium (Cd) has become a serious food security problem, and it is necessary to determine and evaluate the toxic effect and defense mechanism of long-term heavy metal pollution in grain. In order to evaluate the effects of long-term heavy metal Cd stress on the stored grain pests, Aleuroglyphus ovatus were fed with an artificial diet supplemented with different concentrations of Cd (0, 5, 10, 20 mg/kg). The development, fecundity and detoxification enzymes of A. ovatus were analyzed and observed. In this study, the immature duration of A. ovatus was significantly prolonged under long-term Cd stress. Moreover, the survival duration of female adults was significantly shortened. The total number of eggs laid and the daily number laid per female adult decreased significantly. There were significant differences in protein content at protonymph and tritonymph stages when the concentration of Cd exceeded 10 mg/kg. The protein content of female adults was higher than that of male adults. The activity of detoxification enzymes showed differences in different conditions, such as development stage, Cd concentration and gender. These findings confirmed that A. ovatus were sensitive to Cd, and their offspring were severely affected under long-term Cd stress. Therefore, A. ovatus is a good model for evaluating the toxicity of long-term heavy metal Cd stress. The study provides the basis and enriches the research content of heavy metal pollution on mites, contributing to the harmonious and healthy development between the environment and human beings.

Mites, ticks, anaphylaxis and allergy: The Acari hypothesis

Anaphylaxis is a poorly understood immune process in which a Th2-/IgE-mediated adaptive response commandeers cellular machinery, typically reserved for defense against multicellular ectoparasites, to activate against otherwise benign molecules. Its clinical manifestations consist of rapid pathophysiological reflexes that target epithelial surfaces. The galactose-α-1,3-galactose hypersensitivity response is a compelling model of anaphylaxis for which causation has been demonstrated. At the core of the model, a tick bite sensitizes a recipient to a tick foodstuff. As proposed herein, the model likely informs on the origin of all allergic inflammation; namely, allergy is not intended to protect against seemingly harmless and irrelevant materials, but is, instead, intended to rid epithelial surfaces of pathogen-bearing Acari, i.e., mites and ticks. The demonstrated adjuvant activity of acarian gastrointestinal secretions, when paired with the polyphagous diet of mites, renders acarians eminently suited to accounting, mechanistically, for many, if not all, human allergies.

Storage Mite Infestation of Dry-Stored Food Products and Its Relation to Human Intestinal Acariasis in the City of Minia, Egypt

Initial data on the prevalence of storage mites in dry-stored food products and estimates of the presence of mites in human stool in the city of Minia, Egypt are provided. In total, 847 samples were collected randomly from houses and retail stores between March 2017 and February 2018. In addition, 1,000 human stool samples were collected for the detection of the presence of mites. Mites were extracted from 285 of 840 (33.9%) samples, and mite contamination was found to be most prevalent in wheat flour (73.3%). In total, 11 mite species belonging to six families were identified, with the pest species Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) (TP) being the most prevalent (91.2% of samples). The seasonal density distribution showed the highest storage mite density in March-April, followed by October, and the lowest in January. In addition, mites were detected in 87 (8.7%) human stool samples, with significant associations between certain occupations and some personal characteristics. Therefore, more attention needs to be paid to intestinal acariasis arising from mite infestation of dry-stored food products.

A Gustatory Receptor Used for Rapid Detection of Tyrophagus putrescentiae in Fungi Hosts

The storage mite, Tyrophagus putrescentiae, found worldwide in many habitats, is an important pest of edible fungi in China. Storage mites are tiny and difficult to observe, especially when they occur in fungi composts. In this study, one gustatory receptor protein (TputGR1) was identified from the transcriptome of T. putrescentiae. Phylogenetic analysis of GRs families from 10 arthropod species revealed that TputGR1 had high homology with the SccaGR1 of Sarcoptes scabiei and TurtGR1-2 of Tetranychus urticae, but low homology with other insect species, Drosophila melanogaster, Anopheles gambiae, Bombyx mori, Aedes aegypti, Culex quinquefasciatus, and Pediculus humanus. We developed a detection system for the mite on fungi hosts using the GR protein and the loop-mediated isothermal amplification (LAMP). This procedure was rapid (60 min from sampling to result) and had high sensitivity (0.5 ng/mL). LAMP provided rapid and reliable detection of T. putrescentiae. It has good specificity for single samples and for large-scale surveys.

Effect of Fungal Species on the Development and Reproductive Traits of the Fungal-Feeding Mite Rhizoglyphus robini (Astigmata: Acaridae)

The bulb mite, Rhizoglyphus robini (Claparède; Astigmata: Acaridae), is a cosmopolitan pest with a broad host range, including commercially grown edible fungi in China. In this study, we recorded the development and reproductive traits of the bulb mite reared on four mushroom species: Agaricus bisporus Lange, Pleurotus ostreatus Kumm, Pleurotus pulmonarius (Fr.) Quél., and Lentinula edodes (Berk.) Pegler at six constant temperatures ranging from 15 to 31°C and 80% RH. Developmental time for the immature stages was significantly affected by fungal species, ranging from 9.45 ± 1.83 d (reared on L. edodes at 31°C) to 26.39 ± 2.10 d (reared on A. bisporus at 15°C). Edible fungi species significantly affected intrinsic rates of natural increase (rm) at 31°C (varied from 0.23 to 0.28) as did the mite's net reproductive rates (R0) (103.78, 90.43, 70.77, and 97.45, respectively). Longevity, fecundity and female lifespan were dependent on host fungi.

Health Hazards Associated with Arthropod Infestation of Stored Products

Insects and mites are common inhabitants and accidental invaders of food, including durable commodities, and their presence can have both direct and indirect effects on human health. The most common direct effect is contamination of food with arthropod fragments and related contaminants, which may be allergenic or even carcinogenic. The most important indirect effect is that their presence can change the storage microenvironment, making durable products suitable for the rapid development of fungi and other microorganisms. Some of these fungi can produce toxins (e.g., aflatoxins) that endanger human health. Insects may actively or passively contribute to the spread of microorganisms, increasing product contamination, and they may host bacteria that have developed antibiotic resistance, contributing to their spread in food. Several species also may host, attract, or transmit tapeworms, predators, or parasitoids that may affect health. This review synthesizes research on these topics and suggests directions for future research.

Booklice (Liposcelis spp.), Grain Mites (Acarus siro), and Flour Beetles (Tribolium spp.): 'Other Pests' Occasionally Found in Laboratory Animal Facilities

Pests that infest stored food products are an important problem worldwide. In addition to causing loss and consumer rejection of products, these pests can elicit allergic reactions and perhaps spread disease-causing microorganisms. Booklice (Liposcelis spp.), grain mites (Acarus siro), and flour beetles (Tribolium spp.) are common stored-product pests that have previously been identified in our laboratory animal facility. These pests traditionally are described as harmless to our animals, but their presence can be cause for concern in some cases. Here we discuss the biology of these species and their potential effects on human and animal health. Occupational health risks are covered, and common monitoring and control methods are summarized.

Insights Into the Evolution of Chemoreceptor Genes Superfamily in Tyrophagus putrescentiae (Acari: Acaridae)

All living organisms, including animals, plants, fungi, and bacteria, use the olfactory system to recognize chemicals or pheromone from their environment. Insects detect a volatile substance using odorant receptors (ORs) or gustatory receptors (GRs) and ionotropic receptors (IRs). The gene families of the olfactory system in Acari are still not clear. In this study, we identified seven ORs, one GR, and five IRs from the transcriptome of the storage mite, Tyrophagus putrescentiae Schrank. No olfactory coreceptor was found in this transcriptome. Phylogenetic analysis of these gene families with other Arthropoda species revealed the conservation of carbon dioxide receptors in all tested flying insects and T. putrescentiae Most of these ORs and GRs were unique to three mosquitoes (Anopheles gambiae Giles, Culex quinquefasciatus Say, and Aedes aegypti L.), Ixodes scapularis Say and Pediculus humanus L., indicating their involvement in specific aspects of both gustatory and olfactory perception. Some clades contained receptors obtained from all tested insect vector species, indicating a degree of conservation among some vector-dependent OR lineages. IRs family was a highly dynamic and independent original of the chemoreceptor genes subfamily. Our findings would make it possible for future research on the chemosensory recognition mechanism in Acari.

First case of intestinal acariasis from Egypt

We are hereby reporting a case where the eggs and adults of the mold mites; Tyrophagus putrescentiae (Shrank) and the trophozoites of Blastocystis sp. were found in stool of three years old child from Minia City, Egypt. Intestinal mite infection was diagnosed after repeated identification of mite’ stages from six consecutive stool samples to exclude the possibilities of contamination and spurious infection. The patient was suffering from severe colicky abdominal pain and burning sensation around the anus one month ago. All other members of his family were having the same acarine in their feces, but were all symptomless. The patient was treated with ivermectin 200 µg/kg body weight once every 10 days for three doses. His cure indicated that he was having asymptomatic blastocystosis.

Characterization of the complete mitochondrial genome of the storage mite pest Tyrophagus longior (Gervais) (Acari: Acaridae) and comparative mitogenomic analysis of four acarid mites

Mites of the genus Tyrophagus are economically important polyphagous pest commonly living on stored products and also responsible for allergic reactions to humans. Complete mitochondrial genomes (mitogenomes) and the gene features therein are widely used as molecular markers in the study of population genetics, phylogenetics as well as molecular evolution. However, scarcity on the sequence data has greatly impeded the studies in these areas pertaining to the Acari (mites and ticks). Information on the Tyrophagus mitogenomes is quite critical for phylogenetic evaluation and molecular evolution of the mitogenomes within Acariformes. Herein, we reported the complete mitogenome of the allergenic acarid storage mite Tyrophagus longior (Astigmata: Acaridae), an important member of stored food pests, and compared with those of other three acarid mites. The complete mitogenome of T. longior was a circular molecule of 13,271 bp. Unexpectedly, only 19 transfer RNA genes (tRNAs) were present, lacking trnF, trnS1 and trnQ. Furthermore, it also contained 13 protein-coding genes (PCGs) and 2 genes for rRNA (rrnS and rrnL) commonly detected in metazoans. The four mitogenomes displayed similar characteristics with respect to the gene content, nucleotide comparison, and codon usages. Yet, the gene order of T. longior was different from that in other Acari. The J-strands of the four mitogenomes possessed high A+T content (67.4-70.0%), and exhibited positive GC-skews and negative AT-skews. Most inferred tRNAs of T. longior were extremely truncated, lacking either a D- or T-arm, as found in other acarid mites. In T. longior mitogenome the A+T-rich region was just 50 bp in length and can be folded as a stable stem-loop structure, whereas in the region some structures of microsatellite-like (AT)n and palindromic sequences was not present. Besides, reconstructing of the phylogenetic relationship based on concatenated amino acid sequences of 13 PCGs supported that monophyly of the family Acaridae and the order Astigmata, to which the former belongs. Our results were consistent with the traditional classifications.

Temperature-Dependent Development and Reproductive Traits of Tyrophagus putrescentiae (Sarcoptiformes: Acaridae) Reared on Different Edible Mushrooms

China is the largest producer, consumer, and exporter of mushrooms in the world. The storage mite, Tyrophagus putrescentiae Schrank, is one of the most important arthropod pests in mushroom cultivation. This study investigated the development and reproductive traits of this mite reared on four mushroom species: Agaricus bisporus Lange, Pleurotus ostreatus Kumm, Auricularia polytricha (Mont.) Sacc., and Flammulina velutipes (Fr.) Sing., at seven constant temperatures ranging from 16 to 34 °C at 80% relative humidity. Development time for the immature stages decreased with increasing temperature, and was also significantly affected by mushroom species. The shortest immature developmental period (7.0 ± 0.2 d) was observed at 31 °C when reared on F. velutipes, while the longest development was at 16 °C (36.0 ± 0.3 d) reared on P. ostreatus. The effects of temperature and mushroom hosts on the development, female longevity, and reproduction were also significant. The lower threshold temperatures from egg-to-adult for the four mushroom species were 11.97, 12.02, 10.80, and 11.57 °C, for A. bisporus, P. ostreatus, Au. polytricha, and F. velutipes, and the thermal constants were 133.3, 136.8, 165.2, and 135.9 degree days (°C d), for the same mushroom species, respectively. Life table parameters at 25 °C were estimated as follows: net reproductive rates (R0), 59.16, 28.94, 42.62, and 62.93, and intrinsic rate of natural increase (rm), 0.24, 0.13, 0.17, and 0.24, respectively. These results suggest that these mushrooms are suitable hosts for T. putrescentiae, and the storage mite may be able to adapt to higher temperatures.

The complete mitochondrial genome of the brown leg mite, Aleuroglyphus ovatus (Acari: Sarcoptiformes): evaluation of largest non-coding region and unique tRNAs

The circular mitochondrial genome (mitogenome) of Aleuroglyphus ovatus was sequenced. It was 14,328 bp long, and consisted of 37 coding genes including 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. This is the first description of the complete mitogenome of a species in the Acaridae (Acari: Sarcoptiformes). The mtDNA gene order for A. ovatus is identical to those of Dermatophagoides farinae and D. pteronyssinus, but distinctly different from the mtDNA of other Acari. Most inferred tRNA genes of A. ovatus are extremely truncated (48-62 bp), lack stem-loops on either the T- or D-arm (except the trnK), and are unable to fold into the canonical tRNA cloverleaf structure. The largest non-coding region (378 bp) contained several conserved sequences involved in the regulation of mitogenome replication, including one core sequence (ACAT) associated with termination of the J-strand replication and several hypothetical stem-loop structures. The microsatellite-like (AT)n sequence in the largest non-coding region was observed in two other Astigmata species, but it has not been found in other Acari.

When mites attack: domestic mites are not just allergens

Domestic mite species found in indoor environments and in warm or tropical regions are well known for causing allergic disorders. However, little is known about human acariasis, in which mites invade and parasitize the human body in various tissues from the gastrointestinal tract to the lung. Here, we summarize the reported cases of human acariasis of pulmonary, intestinal, oral (anaphylaxis), urinary, otic, and vaginal systems. Because the clinical symptoms of acariasis often overlap with other disease symptoms leading to frequent misdiagnosis, we highlight the need for more attention on these infections.

Emerging risk of infestation and contamination of dried fruits by mites in the Czech Republic

The introduction of live insects into human food is rare in developed countries. However, we report, for the first time, an emerging risk that exists from dried fruit in Central Europe. Recently, massive and frequent infestation of dried fruit imported from the Mediterranean region by the mite, Carpoglpyhus lactis L. (Acarina: Carpoglyphidae), has been found. In 180 samples taken from supermarkets, 13% were contaminated; the contamination levels ranged from 0 to 660 mites per g of dried fruit. The contamination was found in dried apricots, figs, plums and raisins. To estimate the risks and food preferences of C. lactis, its growth rate was examined under laboratory conditions. Starting with a hypothetical population of 10 mites per g of dried fruit, the risk level of 1000 mites per g of dried fruit is reached at 42 days for dried figs, 49 days for dried pineapple and 63 days for dried apricots, dates and plums at 25 °C and 85% relative humidity. We found that mites are able to enter every dried fruit packing material tested, including polypropylene and aluminum foils. This indicates that mites can move from package to package in supermarkets. Mites are known as allergen producers and vectors of mycotoxin-producing fungi. These findings indicate that an increased risk of C. lactis contamination exists in dried fruit.

Acaricidal effects of natural six-carbon and nine-carbon aldehydes on stored-product mites

The toxicities of three plant volatiles, (2E)-hexenal, (2E, 6Z)-nonadienal and (2E)-nonenal, intermediate products of the oxylipin biosynthesis pathway, were tested on three mites of importance for medical purposes and as pests. The aldehydes were diluted in hexane separately and incorporated into diets in ranges of 4-143 mg g(-1). The final density of mites in control and aldehyde-enriched diets was compared after 21 days. The aldehydes were toxic to the mites, whose final density showed an inverse correlation with aldehyde concentration. In addition to the effects of aldehyde concentration, the final density of mites was also influenced by the different aldehydes tested and the interaction among aldehyde concentration and chemical structure. In a functional combination of aldehydes and species, the doses calculated for growth inhibition and eradication of mites ranged from 4 to 35 mg g(-1) and from 36 to 314 mg g(-1), respectively. Due to the protective role displayed by natural six-carbon and nine-carbon aldehydes, these compounds are potential candidates for controlling stored-product mites in stored food and feed products.

Mites in clinical stool specimens: potential misidentification as helminth eggs

We report the finding of unexpected microscopic oval structures in clinical stool samples processed by AFIP/Medicina Laboratorial, a laboratory performing routine clinical analysis in São Paulo, Brazil. Surprisingly, these objects were identified as mite eggs, sometimes accompanied by adult mites. Because misidentification of mite eggs as helminth ova may lead to erroneous treatment with far-reaching consequences, we sought to verify the frequency of adult mites and mite eggs among a number of processed stool specimens. Given their similarity to some helminth eggs, it is important that clinical laboratories recognize these structures, especially in geographic regions where intestinal parasitosis is prevalent.

Experimental method for isolating and identifying dust mites from sputum in pulmonary acariasis

The aim of this study was to pilot a simpler and more effective method for identifying dust mites in sputum. Dust mites and their allergens have been implicated in respiratory diseases, including pulmonary acariasis, and several studies have identified mites in sputum. Further research is dependent on the development of a faster and simpler diagnostic test. We have demonstrated that dust mites artificially introduced into sputa, could be identified after the sputa were liquefied with bleach, when the liquid sample was observed under the microscope. Liquefaction times for serous, mucous, purulent and hemoptoic sputa varied from 10 to 30 min (mean 17.5). The test had a sensitivity of 80% (95% CI 68.2-88.2%) as 46/60 mites were identified. This procedure can be performed quickly at room temperature, is simple, inexpensive, repeatable, and less labourious than previous methods.

Clinical significance of mites in urine

We report a case where a mite egg found in urine caused diagnostic confusion. The possibility of gut or bladder mite infection should be entertained only after repeated identification of mites in urine or stool samples from a symptomatic patient with no other cause for the symptoms and where the possibilities of contamination and spurious infection have been excluded.

Acaroid mites (Acari: Astigmata) in Chinese traditional medicines

Almost 2000 samples of the dried plants and animals used in Chinese traditional medicine were collected from a storehouse in Huainan city, Anhui province, China, where they had been kept for at least 6 months. When examined, every sample was found to contain acaroid mites. The mites included representatives of 44 species belonging to 22 genera and seven families. It seems that samples of Chinese traditional medicine frequently become severely infested with mites while in storage. More importance should be attached to protecting the medicines against mite infestation and to protecting against acariasis those who ingest or simply handle the medicines.