Ocular Dirofilariasis Case in Thailand Confirmed by Molecular Analysis to Be Caused by Dirofilaria immitis

A rare ocular dirofilariasis case along with the clinical characteristics, treatment, and outcome is reported. A whitish roundworm (10.6 cm long and 0.5 mm width) emerged from the pterygium, a triangular tissue growth on the cornea of the eye, of a male patient. The worm had a rounded anterior part, mouth without lips, smooth cuticular surface, and short rounded posterior tail with spicules: these features suggested that it was a male Dirofilaria sp. Molecular identification confirmed that the worm belonged to Dirofilaria immitis. This is the first molecular confirmation that D. immitis is a causative agent of ocular dirofilariasis in Thailand: dirofilariasis is a newly emerging zoonotic disease. Physicians should be alert to zoonotic filarial worms and knowledgeable about treatment of this disease.

Reduction in Insect Attachment Caused by Different Nanomaterials Used as Particle Films (Kaolin, Zeolite, Calcium Carbonate)

In the present investigation, we compared the reduction in attachment ability of the southern green stinkbug Nezara viridula (Hemiptera: Pentatomidae) to glass induced by three different nanoparticle (kaolin, zeolite, and calcium carbonate) films. Using traction force experiments, behavioral experiments, and scanning electron microscopy observations, we analyzed the insect attachment ability and linear speed on untreated and treated glass with the three particle films. The three nanomaterials strongly reduced insect attachment ability mainly owing to contamination of attachment pads. The ability to reduce insect attachment was different for the three tested particle films: kaolin and zeolite induced a significantly higher reduction in N. viridula safety factor than calcium carbonate. The coating of the surface was more uniform and compact in kaolin and zeolite compared to calcium carbonate particle film. Moreover, kaolin and zeolite particles can more readily adhere to N. viridula attachment devices, whereas calcium carbonate particles appeared less adherent to the cuticular surface compared to the two aluminosilicate (kaolin and zeolite) particles. Only the application of kaolin reduced insect linear speed during locomotion. Nanoparticle films have a great potential to reduce insect attachment ability and represent a good alternative to the use of insecticides for the control of pentatomid bugs and other pest insects.

The role of houseflies, Musca domestica L. (Diptera: Muscidae) as a mechanical vector for ESKAPE pathogens and drug resistance

Introduction: The housefly (Musca domestica) is an important host for various pathogenic bacteria, including the ESKAPE group and acts as a reservoir for transmitting resistance factors. In this regard, this study was performed in order to survey the role of houseflies as a mechanical vector for ESKAPE pathogens and antibiotic resistance profiles of these strains in the four teaching hospitals and rural area in Babol, north of Iran. In this cross-sectional study, 280 adult house flies were collected with a sterilized nylon net. Methods: All samples were put inside separately in a sterile tube and anesthetized using freezing at 0ᵒC for 5 minutes. Bacterial isolates were identified from the external and internal surfaces. The antibiotic susceptibility test was performed by the disk diffusion method. A. baumannii, P. aeruginosa and Enterobacter isolates were not detected in rural samples. Only, one methicillin-resistance S. aureus was found in rural flies. In hospitals, the prevalence of the ESKAPE pathogens in the Cuticular surface and GI were 22.9% and 22.1%, respectively. Results: In total, the highest and lowest frequency rate was related to P. aeruginosa (6.1%) and A. baumannii (1.1%). Also, 66.7%, 5.9% and 12.5% of A. baumannii, P. aeruginosa and Enterobacter were resistant to imipenem, respectively. 21.4% of E. faecium were resistant to vancomycin. In total, 63 (22.5%) bacterial species collected from both the Cuticular surface and GI, 29 (46%) were multidrug-resistant (MDR). Conclusion: Houseflies obtained from hospitals may be involved in the distribution of drug-resistant bacteria and may increase the potential of human exposure to drug-resistant organisms.

Soft ticks perform evaporative cooling during blood-feeding

Feeding on the blood of warm-blooded vertebrates is associated to thermal stress in haematophagous arthropods. It has been demonstrated that blood-sucking insects protect their physiological integrity either by synthesising heat-shock proteins or by means of thermoregulatory mechanisms. In this work, we describe the first thermoregulatory mechanism in a tick species, Ornithodoros rostratus. By performing real-time infrared thermography during feeding on mice we found that this acarian eliminates big amounts of fluid (urine) through their coxal glands; this fluid quickly spreads over the cuticular surface and its evaporation cools-down the body of the tick. The spread of the fluid is possible thanks to capillary diffusion through the sculptured exoskeleton of Ornithodoros. We discuss our findings in the frame of the adaptive strategies to cope with the thermal stress experienced by blood-sucking arthropods at each feeding event warm-blooded hosts.

Collembola cuticles and the three-phase line tension

The cuticles of most springtails (Collembola) are superhydrophobic, but the mechanism has not been described in detail. Previous studies have suggested that overhanging surface structures play an important role, but such structures are not a universal trait among springtails with superhydrophobic cuticles. A novel wetting experiment with a fluorescent dye revealed the extent of wetting on exposed surface structures. Using simple wetting models to describe the composite wetting of the cuticular surface structures results in underestimating the contact angles of water. Including the three-phase line tension allows for a prediction of contact angles in the observed range. The discrepancy between the contact angle predicted by simple models and those observed is especially large in the springtail Cryptopygus clavatus which changes, seasonally, from superhydrophobic to wetting without a large change in surface structure; C. clavatus does not have overhanging surface structures. This large change in observed contact angles can be explained with a modest change of the three-phase line tension.

Comparison and correlation between chemical profiles of cephalic salivary glands and cuticle surface of workers of Apis mellifera (Hymenoptera, Apidae)

The cuticle surface of insects displays functions in communication, such as recognition. It is known that oenocytes are responsible for the origin of the compounds found in the epicuticle. Secretion of exocrine glands might be added to the original composition during the insect’s life. The aims of the present study were (i) to quantify and to qualify the chemical compounds in cephalic salivary glands (CSG) and cuticle surface of workers of Apis mellifera L., 1758; (ii) to compare chemical profiles of both gland and cuticle; (iii) to verify if the epicuticular and CSG profile compositions allow separation of the workers into phase-related groups. Glands and wings of newly emerged workers, nurses, and foragers were analyzed by gas chromatography – mass spectrometry. The results have shown that the main compounds in both were hydrocarbons. The Mantel correspondence analysis showed that there was relatively strong correspondence between CSG and cuticular surface in all groups, mainly nurses and foragers. From a total of 37 detected compounds, 29 were the same in both compartments. The results indicated that the gland secretion might be used to replenish the cuticular compounds. In conclusion, glands and cuticle profiles were phase-related and the CSG may be a potential auxiliary source of cuticular hydrocarbon replenishment in the studied species.