The Potential Use of Volatile Biomarkers for Malaria Diagnosis

Pathogens may change the odor and odor-related biting behavior of the vector and host to enhance pathogen transmission. In recent years, volatile biomarker investigations have emerged to identify odors that are differentially and specifically released by pathogens and plants, or the pathogen-infected or even cancer patients. Several studies have reported odors or volatile biomarkers specifically detected from the breath and skin of malaria-infected individuals. This review will discuss the potential use of these odors or volatile biomarkers for the diagnosis of malaria. This approach not only allows for the non-invasive mean of sample collection but also opens up the opportunity to develop a biosensor for malaria diagnosis in low-resource settings.

Mosquito-Textile Physics: A Mathematical Roadmap to Insecticide-Free, Bite-Proof Clothing for Everyday Life

Garments treated with chemical insecticides are commonly used to prevent mosquito bites. Resistance to insecticides, however, is threatening the efficacy of this technology, and people are increasingly concerned about the potential health impacts of wearing insecticide-treated clothing. Here, we report a mathematical model for fabric barriers that resist bites from Aedes aegypti mosquitoes based on textile physical structure and no insecticides. The model was derived from mosquito morphometrics and analysis of mosquito biting behavior. Woven filter fabrics, precision polypropylene plates, and knitted fabrics were used for model validation. Then, based on the model predictions, prototype knitted textiles and garments were developed that prevented mosquito biting, and comfort testing showed the garments to possess superior thermophysiological properties. Our fabrics provided a three-times greater bite resistance than the insecticide-treated cloth. Our predictive model can be used to develop additional textiles in the future for garments that are highly bite resistant to mosquitoes.

Which Incision is Better for Orthotopic Rat Liver Transplantation, Transverse or Midline?

Orthotopic rat liver transplantation (OLT) is a complex procedure extensively applicable to basic science, myriad complications can occur, incision-related self-biting has not been reported after liver transplantation. For the project of tolerance induction through stem cells, OLT was performed from inbred Sprague Dawley (SD) rat to SD (control group, n = 9), SD to Lewis (chronic rejection, n = 11), and OLT from Lewis allograft to Brown Norway (BN) rats (acute rejection, n = 63), the acute rejection group was sub-grouped into the transverse incision group(n = 26) and midline group(n = 37), Cyclosporine A was injected at 2mg/kg into the rejection groups once daily for 14 days, lidocaine cream alone or with naloxone was used for pain-relieving. The recipient survival and wound status were the primary endpoint of this study. For SD→SD, 30-day survival rate was 88.9%, no self-biting behavior occurred; for SD→Lewis, 30-day survival rate was 54.5%, the degree II of self-biting occurred in 2 cases. For Lewis→BN with transverse incision, 30-day survival rate was 51.8%, severe self-biting occurred in 16 cases in 8–27 days and 5 more cases over 30 days, which caused death or euthanasia, the degree 2 of biting occurred in 2 cases. For Lewis→BN with midline incision, 30-day survival rate was 86.0%, no severe self-biting occurred, mild self-biting in 2 cases. There was difference in the biting–related survival between two sub-groups (p = 0.003). In conclusion, incision-related self-biting behavior is species-specific for rats, the transverse incision is the pain-causing reason; the midline one is effective to avert occurrences.

The seasonal dynamics and biting behavior of potential Anopheles vectors of Plasmodium knowlesi in Palawan, Philippines

Background A small number of human cases of the zoonotic malaria Plasmodium knowlesi have been reported in Palawan Island, the Philippines. Identification of potential vector species and their bionomics is crucial for understanding human exposure risk in this setting. Here, we combined longitudinal surveillance with a trap-evaluation study to address knowledge gaps about the ecology and potential for zoonotic spillover of this macaque malaria in Palawan Island. Methods The abundance, diversity and biting behavior of human-biting Anopheles mosquitoes were assessed through monthly outdoor human landing catches (HLC) in three ecotypes representing different land use (forest edge, forest and agricultural area) across 8 months. Additionally, the host preference and biting activity of potential Anopheles vectors were assessed through comparison of their abundance and capture time in traps baited with humans (HLC, human-baited electrocuting net—HEN) or macaques (monkey-baited trap—MBT, monkey-baited electrocuting net—MEN). All female Anopheles mosquitoes were tested for the presence of Plasmodium parasites by PCR. Results Previously incriminated vectors Anopheles balabacensis and An. flavirostris accounted for > 95% of anophelines caught in longitudinal surveillance. However, human biting densities were relatively low (An. balabacensis: 0.34–1.20 per night, An. flavirostris: 0–2 bites per night). Biting densities of An. balabacensis were highest in the forest edge, while An. flavirostris was most abundant in the agricultural area. The abundance of An. balabacensis and An. flavirostris was significantly higher in HLC than in MBT. None of the 357 female Anopheles mosquitoes tested for Plasmodium infection were positive. Conclusions The relatively low density and lack of malaria infection in Anopheles mosquitoes sampled here indicates that exposure to P. knowlesi in this setting is considerably lower than in neighboring countries (i.e. Malaysia), where it is now the primary cause of malaria in humans. Although anophelines had lower abundance in MBTs than in HLCs, An. balabacensis and An. flavirostris were caught by both methods, suggesting they could act as bridge vectors between humans and macaques. These species bite primarily outdoors during the early evening, confirming that insecticide-treated nets are unlikely to provide protection against P. knowlesi vectors. Graphical abstract

The Seasonal Dynamics and Biting Behavior of Potential Anopheles Vectors of Plasmodium Knowlesi in Palawan, Philippines

Background: A small number of human cases of the zoonotic malaria Plasmodium knowlesi have been reported in Palawan Island, the Philippines. Identification of potential vector species and their bionomics is crucial for understanding of human exposure risk in this setting. Here, we combined longitudinal surveillance with a trap-evaluation study to address knowledge gaps about the ecology and potential for zoonotic spillover of this macaque malaria in Palawan Island.Methods: The abundance, diversity and biting behavior of human-biting Anopheles mosquitoes were assessed through monthly outdoor Human Landing Catches (HLC) in three ecotypes representing different land use (forest-edge, forest and agricultural area) across 8 months. Additionally, the host preference and biting activity of potential Anopheles vectors was assessed through comparison of their abundance and capture time in traps baited with humans (HLC, human-baited electrocuting net – HEN) or macaques (monkey-baited trap – MBT, monkey-baited electrocuting net – HEN). All female Anopheles mosquitoes were tested for presence of Plasmodium parasite by PCR.Results: Previously incriminated vectors Anopheles balabacensis and An. flavirostris accounted for >95% of Anophelines caught in longitudinal surveillance. However human biting densities were relatively low (An. balabacensis: 0.34 -1.20 per night, An. flavirostris: 0-2 bites per night). Biting densities of An. balabacensis were highest in the forest-edge while An. flavirostris was most abundant in the agricultural area. The abundance of An. balabacensis and An. flavirostris was significantly higher in HLC than MBT. None of the 357 female Anopheles mosquitoes tested for Plasmodium infection were positive.Conclusions: The relatively low density and lack of malaria infection in Anopheles mosquitoes sampled here indicates that exposure to P. knowlesi in this setting is considerably lower than neighbouring countries (Malaysia) where it is now the primary cause of malaria in humans. Although Anophelines had lower abundance in MBT than HLC, An. balabacensis and An. flavirostris were caught by both methods suggesting they could act as bridge vectors between humans and macaques. These species bite primarily outdoors and in early evening; confirming that Insecticide Treated Nets are unlikely to provide protection against P. knowlesi vectors.

Morphological Changes in the Mandibles Accompany the Defensive Behavior of Indiana Mite Biting Honey Bees Against Varroa Destructor

The honey bee (Apis mellifera) is the most important managed pollinator to sustainable agriculture and our ecosystem. Yet managed honey bee colonies in the United States experience 30–40% losses annually. Among the many biotic stressors, the parasitic mite Varroa destructor is considered one of the main causes of colony losses. Bees’ mite-biting behavior has been selected as a Varroa-tolerant or Varroa-resistant trait in the state of Indiana for more than a decade. A survey of damaged mites from the bottom of a colony can be used as an extended phenotype to evaluate the mite-biting behavior of a colony. In this study, on average, 37% of mites sampled from the breeding stocks of 59 colonies of mite biters in Indiana were damaged or mutilated, which is significantly higher than the 19% of damaged mites found in commercial colonies in the southern United States. Indiana mite biter colonies had a higher proportion of damaged mites, although among the damaged mites, the number of missing legs was not significantly higher. In addition, the morphology of pollen-forager worker bee mandibles was compared by X-ray microcomputed tomography for six parameters in two populations, and a difference was detected in one parameter. Our results provide scientific evidence that potentially explains the defensive mechanism against Varroa mites: structural changes in the worker bee mandibles.

Is There a Link between Suckling and Manipulation Behavior during Rearing in Pigs?

Inadequate possibilities to perform oral manipulation behavior for pigs can lead to misdirection and thus tail biting. Our study aimed to analyze manipulation behaviors of weaner pigs with focus on tail biting and the relationship with agonistic characteristics of the piglets during suckling. We analyzed the individual manipulation behavior of 188 weaner pigs. General health condition and tail lesions were determined weekly. Correlations were estimated between weight at weaning and at the end of rearing period, frequency of manipulative rearing behaviors and Dominance and social tension index based on suckling behavior. Principal component and cluster analyses were performed to identify groups of piglets which showed similar suckling and rearing behaviors. Tail biting increased at the middle and end of rearing with switching roles of biters and victims. Tail lesions were correlated with received tail biting behavior but occurred with a delay of more than a week. The frequency of performed tail biting was correlated with dominance index (rs = −0.256, p < 0.01) and weaning weight (rs = −0.199, p < 0.05). We assume that performed tail biting is more often observed in pigs who show mainly submissive behavior in teat disputes.