Diurnal biting of malaria mosquitoes in the Central African Republic indicates residual transmission may be "out of control".

Malaria control interventions target nocturnal feeding of the Anopheles vectors indoors to reduce parasite transmission. Mass deployment of insecticidal bed nets and indoor residual spraying with insecticides, however, may induce mosquitoes to blood-feed at places and at times when humans are not protected. These changes can set a ceiling to the efficacy of these control interventions, resulting in residual malaria transmission. Despite its relevance for disease transmission, the daily rhythmicity of Anopheles biting behavior is poorly documented, most investigations focusing on crepuscular hours and nighttime. By performing mosquito collections 48-h around the clock, both indoors and outdoors, and by modeling biting events using circular statistics, we evaluated the full daily rhythmicity of biting in urban Bangui, Central African Republic. While the bulk of biting by Anopheles gambiae, Anopheles coluzzii, Anopheles funestus, and Anopheles pharoensis occurred from sunset to sunrise outdoors, unexpectedly ∼20 to 30% of indoor biting occurred during daytime. As biting events did not fully conform to any family of circular distributions, we fitted mixtures of von Mises distributions and found that observations were consistent with three compartments, corresponding indoors to populations of early-night, late-night, and daytime-biting events. It is not known whether these populations of biting events correspond to spatiotemporal heterogeneities or also to distinct mosquito genotypes/phenotypes belonging consistently to each compartment. Prevalence of Plasmodium falciparum in nighttime- and daytime-biting mosquitoes was the same. As >50% of biting occurs in Bangui when people are unprotected, malaria control interventions outside the domiciliary environment should be envisaged.

Effects of life history strategies and habitats on limb regeneration in plethodontid salamanders.

BACKGROUND: Salamanders are the only tetrapods that exhibit the ability to fully regenerate limbs. The axolotl, a neotenic salamander, has become the model organism for regeneration research. Great advances have been made providing a detailed understanding of the morphological and molecular processes involved in limb regeneration. However, it remains largely unknown how limb regeneration varies across salamanders and how factors like variable life histories, ecologies, and limb functions have influenced and shaped regenerative capacities throughout evolution. RESULTS: This study focuses on six species of plethodontid salamanders representing distinct life histories and habitats. Specimens were examined for regeneration ability after bite injuries as well as after controlled amputations. Morphological investigations revealed great regenerative abilities in all investigated species and frequent anatomical limb anomalies. Correlations were observed with respect to speed of regeneration and habitat. CONCLUSIONS: Investigating regeneration in non-model salamander taxa is essential for disentangling shared features of the regeneration process versus those that may be more taxon-specific. Gaining insights into variable aspects of regeneration under natural conditions and after conspecific biting rather than controlled amputations adds important new datapoints for understanding the evolutionary framework of regeneration and provides a broader context for interpreting findings made in the model organism axolotl.

Nestling sex and behaviour determine the host preference of insect vectors in avian nests.

Sexual differences in pathogen prevalence in wildlife often arise from varying susceptibility influenced by factors such as sex hormones and exposure to pathogens. In the case of vector-borne pathogens, host selection by insect vectors determines the exposure of hosts to infections, largely affecting the transmission of these infectious diseases. We identify the blood-feeding patterns of insect vectors in Blue Tit (Cyanistes caeruleus) nestlings in a 3-year study. Blood from both nestlings and insect vectors (Culicoides spp. and Simuliidae) captured inside nest-boxes were used to molecularly determine the sex of the host. We then compared the sex-ratios of the nestlings that had been bitten and those of the complete brood in each nest. We found that males were bitten more frequently than females in 2021, when males weighed less in comparison to other years. Additionally, we molecularly identified bitten nestlings individually by genotyping the DNA of blood obtained from both, the vector's abdomen and nestlings of each brood in 2022. Nestlings more frequently bitten by vectors were males, weighed less and were closest to the nest entrance. To our knowledge this is the first study identifying the nestling selection by insect vectors in bird nests under natural conditions. These results contribute to understanding the mechanisms of host selection by insect vectors, shedding light on pathogen transmission and offering insights into the observed sex-biased infections in wildlife populations.

Bite hard: Linking cranial loading mechanics to ecological differences in gnawing behavior in caviomorph rodents.

The mammalian skull is very malleable and has notably radiated into highly diverse morphologies, fulfilling a broad range of functional needs. Although gnawing is relatively common in mammals, this behavior and its associated morphology are diagnostic features for rodents. These animals possess a very versatile and highly mechanically advantageous masticatory apparatus, which, for instance, allowed caviomorph rodents to colonize South America during the Mid-Eocene and successfully radiate in over 200 extant species throughout most continental niches. Previous work has shown that differences in bite force within caviomorphs could be better explained by changes in muscle development than in mechanical advantages (i.e., in cranial overall morphology). Considering the strong bites they apply, it is interesting to assess how the reaction forces upon the incisors (compression) and the powerful adductor musculature pulling (tension) mechanically affect the cranium, especially between species with different ecologies (e.g., chisel-tooth digging). Thus, we ran finite element analyses upon crania of the subterranean Talas' tuco-tuco Ctenomys talarum, the semi-fossorial common degu Octodon degus, and the saxicolous long-tailed chinchilla Chinchilla lanigera to simulate: (A) in vivo biting in all species, and (B) rescaled muscle forces in non-ctenomyid rodents to match those of the tuco-tuco. Results show that the stress patterns correlate with the mechanical demands of distinctive ecologies, on in vivo-based simulations, with the subterranean tuco-tuco being the most stressed species. In contrast, when standardizing all three species (rescaled models), non-ctenomyid models exhibited a several-fold increase in stress, in both magnitude and affected areas. Detailed observations evidenced that this increase in stress was higher in lateral sections of the snout and, mainly, the zygomatic arch; between approximately 2.5-3.5 times in the common degu and 4.0-5.0 times in the long-tailed chinchilla. Yet, neither species, module, nor simulation condition presented load factor levels that would imply structural failure by strong, incidental biting. Our results let us conclude that caviomorphs have a high baseline for mechanical strength of the cranium because of the inheritance of a very robust "rodent" model, while interspecific differences are associated with particular masticatory habits and the concomitant level of development of the adductor musculature. Especially, the masseteric and zygomaticomandibular muscles contribute to >80% of the bite force, and therefore, their contraction is responsible for the highest strains upon their origin sites, that is, the zygomatic arch and the snout. Thus, the robust crania of the subterranean and highly aggressive tuco-tucos allow them to withstand much stronger forces than degus or chinchillas, such as the ones produced by their hypertrophied jaw adductor muscles or imparted by the soil reaction.

Scaling of buccal mass growth and muscle activation determine the duration of feeding behaviours in the marine mollusc Aplysia californica.

The mechanical forces experienced during movement and the time constants of muscle activation are important determinants of the durations of behaviours, which may both be affected by size-dependent scaling. The mechanics of slow movements in small animals are dominated by elastic forces and are thus quasistatic (i.e. always near mechanical equilibrium). Muscular forces producing movement and elastic forces resisting movement should scale identically (proportional to mass2/3), leaving the scaling of the time constant of muscle activation to play a critical role in determining behavioural duration. We tested this hypothesis by measuring the duration of feeding behaviours in the marine mollusc Aplysia californica whose body sizes spanned three orders of magnitude. The duration of muscle activation was determined by measuring the time it took for muscles to produce maximum force as A. californica attempted to feed on tethered inedible seaweed, which provided an in vivo approximation of an isometric contraction. The timing of muscle activation scaled with mass0.3. The total duration of biting behaviours scaled identically, with mass0.3, indicating a lack of additional mechanical effects. The duration of swallowing behaviour, however, exhibited a shallower scaling of mass0.17. We suggest that this was due to the allometric growth of the anterior retractor muscle during development, as measured by micro-computed tomography (micro-CT) scans of buccal masses. Consequently, larger A. californica did not need to activate their muscles as fully to produce equivalent forces. These results indicate that muscle activation may be an important determinant of the scaling of behavioural durations in quasistatic systems.

Livestock keeping, mosquitoes and community viewpoints: a mixed methods assessment of relationships between livestock management, malaria vector biting risk and community perspectives in rural Tanzania.

BACKGROUND: Livestock keeping is one of the potential factors related to malaria transmission. To date, the impact of livestock keeping on malaria transmission remains inconclusive, as some studies suggest a zooprophylactic effect while others indicate a zoopotentiation effect. This study assessed the impact of livestock management on malaria transmission risks in rural Tanzania. Additionally, the study explored the knowledge and perceptions of residents about the relationships between livestock keeping and malaria transmission risks in a selected village. METHODS: In a longitudinal entomological study in Minepa village, South Eastern Tanzania, 40 households were randomly selected (20 with livestock, 20 without). Weekly mosquito collection was performed from January to April 2023. Indoor and outdoor collections used CDC-Light traps, Prokopack aspirators, human-baited double-net traps, and resting buckets. A subsample of mosquitoes was analysed using PCR and ELISA for mosquito species identification and blood meal detection. Livestock's impact on mosquito density was assessed using negative binomial GLMMs. Additionally, in-depth interviews explored community knowledge and perceptions of the relationship between livestock keeping and malaria transmission risks. RESULTS: A total of 48,677 female Anopheles mosquitoes were collected. Out of these, 89% were Anopheles gambiae sensu lato (s.l.) while other species were Anopheles funestus s.l., Anopheles pharoensis, Anopheles coustani, and Anopheles squamosus. The findings revealed a statistically significant increase in the overall number of An. gambiae s.l. outdoors (RR = 1.181, 95%CI 1.050-1.862, p = 0.043). Also, there was an increase of the mean number of An. funestus s.l. mosquitoes collected in households with livestock indoors (RR = 2.866, 95%CI: 1.471-5.582, p = 0.002) and outdoors (RR = 1.579,95%CI 1.080-2.865, p = 0.023). The human blood index of Anopheles arabiensis mosquitoes from houses with livestock was less than those without livestock (OR = 0.149, 95%CI 0.110-0.178, p < 0.001). The majority of participants in the in-depth interviews reported a perceived high density of mosquitoes in houses with livestock compared to houses without livestock. CONCLUSION: Despite the potential for zooprophylaxis, this study indicates a higher malaria transmission risk in livestock-keeping communities. It is crucial to prioritize and implement targeted interventions to control vector populations within these communities. Furthermore, it is important to enhance community education and awareness regarding covariates such as livestock that influence malaria transmission.

Extensive Schmallenberg virus circulation in Germany, 2023.

Schmallenberg virus (SBV) and bluetongue virus (BTV) are both transmitted by Culicoides biting midges and infect predominantly ruminants. To investigate the extent of virus spread in the 2022 and 2023 vector seasons, we serologically tested wild ruminants from western Germany. While antibodies against BTV were not detected in any animal, regardless of age or sampling time, numerous wild ruminants tested positive for antibodies to SBV. In 2022, a low seroprevalence of 4.92% was measured. In sharp contrast, 40.15% of the animals tested positive in 2023. Of the young animals, about 31.82% were seropositive, clearly indicating large-scale SBV circulation in summer and autumn 2023.

Isolation and whole-genome sequence analysis of Balagodu virus in Japan.

Whole-genome sequencing of a virus isolated from Culicoides biting midges in southern Japan in 2020 revealed that it is a strain of Balagodu virus (BLGV; genus Orthobunyavirus; family Peribunyaviridae; order Bunyavirales). A solitary instance of BLGV isolation occurred in India in 1963. All assembled segments comprise complete protein-coding sequences that are similar to those of other orthobunyaviruses. The consensus 3'- and 5'-terminal sequences of orthobunyaviruses' genomic RNAs are also conserved in the Japanese BLGV strain. Here, we update the geographic distribution of BLGV and provide its complete sequence, contributing to the clarification of orthobunyavirus phylogeny.

The possible role of haematophagous flies in the incidence of bovine teat papillomatosis.

The relationship between the incidence of bovine teat papillomatosis and the activity of haematophagous flies was investigated in Japan. A total of 15,737 flies consisting of 33 species were collected by dry ice-baited mosquito net (DMN) trap and a sweep net from udders of cattle. Simulium aokii (Takahasi) of Simuliidae (black flies) was the predominant species, followed by S. tobetsuense Ono and S. iwatense (Shiraki). Simulium aokii had the highest peak in October, followed by September. Numbers of blood spots from the bites per teat in nulliparous cattle were significantly correlated with numbers of S. aokii collected by DMN trap. Numbers of teats with warts and spots of blood from the bites per teat were significantly more abundant in anterior teats than posterior teats. The average incidence of teat papillomatosis in nulliparous cattle was significantly higher than that in parous cattle, and the highest incidence by month was in May, followed by April. Although bovine papillomavirus (BPV) DNA was not detected in flies examined, the presence of black flies and blood spots from their bites were associated with subsequent high incidence of growing warts. In particular, it would pay to give attention to species such as S. aokii that severely attack udders in the present locality. Further investigations for the detection of BPV DNA from flies parasitizing on teats are needed.

Winter activity of Culicoides (Diptera: Ceratopogonidae) inside and outside stables in Germany.

Culicoides biting midge species (Diptera: Ceratopogonidae) of the Obsoletus Group and the Pulicaris Complex are considered the major vectors of bluetongue and Schmallenberg viruses in Europe. Overwintering strategies of these arboviruses are controversially discussed, with the ongoing activity of vector species and a non-disrupted transmission cycle during winter being a plausible explanation. Although data on Culicoides winter activity are relatively scant, a seasonal vector-free period (SVFP), during which adult Culicoides are not or hardly active, is questionable. To determine winter activity and define SVFPs according to the EU Commission Regulation No 1266/2007, adult Culicoides were trapped weekly with UV-light traps from October to April 2019/2020 and 2020/2021 inside and outside stables on 16 farms throughout Germany. Temperature measurements were taken regularly at each trapping site since the temperature is a known driver of biting midge activity. In 960 indoor and outdoor catches, 32,377 Culicoides were trapped, with 90.9% of them belonging to the Obsoletus Group, 6.1% to the Pulicaris Complex and 3.0% to 'other Culicoides' according to morphological identification. The majority (61.3%) of Culicoides were trapped indoors, with substantial numbers of specimens collected from October to December, in March and in April, and only a few or no specimens in January and February. Obsoletus Group biting midges were active indoors for almost the entire winter. Outdoors, Culicoides numbers decreased from October to December, few or no specimens were caught from January to March, and high numbers were captured in April. Of the collected Culicoides, 2028 were blood-fed, of which 94.6% were trapped in the stables. The indoor SVFP, although calculated for blood-fed instead of parous females, lasted for almost 4 months (late November until mid-March) in winter 2019/2020 and 2 months (January and February) in winter 2020/2021. The outdoor SVFPs covered almost the entire study period in both winters, with slight differences between the onsets and the ends. The Culicoides activity significantly depended on temperature. Specimens of the Obsoletus Group were caught at an average temperature of 7.4°C (minimum 0.3°C) and of the Pulicaris Complex at an average temperature of 10.3°C (minimum 1.2°C). These temperatures were reached inside the stables over more extended periods than outside. The average indoor temperatures were 1.2 K higher than the average outdoor temperatures, although absolute temperature differences of up to 9.0 K were recorded. Based on Culicoides activity, the results of the present study indicate an almost continuous potential for virus transmission in winter within livestock houses.

Blood meal sources of mosquitoes (Diptera: Culicidae) in domestic and open green environments from two urbanisations of temperate Argentina.

Understanding the blood-feeding patterns of mosquitoes is essential for evaluating their potential as disease vectors, especially in urban areas where mosquitoes coexist with humans, domestic animals and wildlife. This study aimed to bridge a substantial gap in regional knowledge by identifying the blood meal sources of field-collected mosquitoes in domestic and open green environments from two urbanisations of temperate Argentina, the Área Metropolitana de Buenos Aires (AMBA) and Tandil, using molecular techniques. Female mosquitoes were collected from November 2019 to March 2020 and April-May 2021. A bipartite network analysis was performed for each environment and urbanisation. A total of 103 blood meals from Aedes (2 species) and Culex (7 species) were identified. Among these, five mammal and 18 bird species were recognised as hosts. Aedes mosquitoes exclusively fed on mammals, while Culex mosquitoes exhibited a broader host range including both birds and mammals. In AMBA, the open green environments were composed by more mosquito species than the domestic environments, while both presented similar numbers of vertebrate species. In contrast, in open green environments from Tandil only blood-fed Aedes albifasciatus were collected. For open green environments of AMBA and domestic environments of Tandil, results suggested some degree of host selection. For the three main vectors of diseases in the region, Aedes aegypti, Ae. albifasciatus and Culex pipiens molestus, we present the first molecular evidence of human blood meals in South America. Epidemiological significance of the present findings is discussed.

Does malocclusion affect ingestion: a systematic review.

OBJECTIVES: The multifactorial aspect of malocclusions and their consequences on ingestion function is rarely described in the literature. The aims of this review are (i) to investigate the relationship between oral ingestion and malocclusion and (ii) to gather malocclusion tools that could help screen subjects at risk of malocclusion-related ingestion disorders. MATERIAL AND METHODS: A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P 2015) guidelines. The analysis methods and inclusion criteria have been documented in a protocol published in the Prospective International Register of Systematic Reviews (PROSPERO) under the registration number CRD42023395840. The bibliographic search involved the PubMed®, Cochrane and PROSPERO databases. RESULTS: A total of 29 articles published between 2007 and 2023 were retained by the search criteria for the qualitative synthesis. Twenty of the studies found that the severity of malocclusion has a negative impact on oral ingestion. This review highlights that malocclusion and ingestion impairments are associated but it is not possible to determine causality due to the observational approach of many of the studies. CONCLUSION: Malocclusion has a negative impact on ingestion function. During orthodontic consultations, particular interest should be directed towards chewing, biting, and swallowing disorders, which can affect patients' nutritional status. This review offers arguments for designing further studies assessing the extent to which malocclusions may affect nutritional status. CLINICAL RELEVANCE: Orthodontic treatment should focus on improving patients' ingestion.

Timely Questions Emerging in Chronobiology: The Circadian Clock Keeps on Ticking.

Chronobiology investigations have revealed much about cellular and physiological clockworks but we are far from having a complete mechanistic understanding of the physiological and ecological implications. Here we present some unresolved questions in circadian biology research as posed by the editorial staff and guest contributors to the Journal of Circadian Rhythms. This collection of ideas is not meant to be comprehensive but does reveal the breadth of our observations on emerging trends in chronobiology and circadian biology. It is amazing what could be achieved with various expected innovations in technologies, techniques, and mathematical tools that are being developed. We fully expect strengthening mechanistic work will be linked to health care and environmental understandings of circadian function. Now that most clock genes are known, linking these to physiological, metabolic, and developmental traits requires investigations from the single molecule to the terrestrial ecological scales. Real answers are expected for these questions over the next decade. Where are the circadian clocks at a cellular level? How are clocks coupled cellularly to generate organism level outcomes? How do communities of circadian organisms rhythmically interact with each other? In what way does the natural genetic variation in populations sculpt community behaviors? How will methods development for circadian research be used in disparate academic and commercial endeavors? These and other questions make it a very exciting time to be working as a chronobiologist.

Chemical Composition, Repellent, and Oviposition Deterrent Potential of Wild Plant Essential Oils against Three Mosquito Species.

In this study, the chemical composition, repellent, and oviposition deterrent effects of five plant essential oils (EOs) extracted from Lantana camara (Verbenaceae), Schinus terebinthifolia (Anacardiaceae), Callistemon viminalis (Myrtaceae), Helichrysum odoratissimum (Asteraceae), and Hyptis suaveolens (Lamiaceae) were evaluated against Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus. When tested at 33.3 µg/cm2, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum were effective repellents against Ae. aegypti (89%, 91%, 90%, and 51% repellency, respectively), but they were less repellent against An. gambiae (66%, 86%, 59%, and 49% repellency, respectively). Interestingly, L. camara, S. terebinthifolia, C. viminalis, and H. odoratissimum exhibited 100% repellency against Cx. quinquefasciatus at 33.3 µg/cm2. In time-span bioassays performed at 333 µg/cm2, the EO of L. camara exhibited 100% repellence against Ae. aegypti and An. gambiae for up to 15 min and against Cx. quinquefasciatus for 75 min. The oviposition bioassays revealed that L. camara exhibited the highest activity, showing 85%, 59%, and 89% oviposition deterrence against Ae. aegypti, An. gambiae, and Cx. quinquefasciatus, respectively. The major compounds of L. camara, S. terebinthifolia, and C. viminalis were trans-ß-caryophyllene (16.7%), α-pinene (15.5%), and 1,8-cineole (38.1%), respectively. In conclusion, the L. camara and S. terebinthifolia EOs have the potential to be natural mosquito repellents.

3D Printing/Additive Manufacturing of Single- Implant Overdentures. A Randomized controlled clinical trial.

OBJECTIVES: Mandibular single-implant overdenture is a well-established treatment modality for the management of completely edentulous patients. The use of CAD/CAM printing technology to fabricate complete dentures and overdentures is burgeoning. The trial aimed to clinically evaluate 3D-printed single-implant overdentures and compare outcomes to those of overdentures manufactured using conventional techniques. MATERIALS AND METHODS: A randomized clinical trial (RCT) was designed. Twenty-eight participants were randomly allocated into two equal groups. Participants in the control group received conventionally manufactured single-implant overdentures, while participants in the printed group received digital light processing (DLP) printed single-implant overdentures. An evaluation was conducted to assess the rates of implant survival and success, as well as overdenture survival and success, along with the measurement of maximum biting force (MBF) over a one-year follow-up period. Data was collected and subjected to statistical analysis. Statistical significance was determined using a two-sided p-value with a threshold of less than 0.05. RESULTS: The printed denture group had higher implant survival (100%) and success rates (92.8%) compared to the conventional denture group (85.7% survival, 85.7% success). Overdenture survival and success rates were 100% in the printed group and 78.6% in the conventional group. Both groups showed a significant increase in maximum biting force (MBF) at 3, 6, and 12 months of follow-up (P<0.001). The printed group demonstrated a statistically significant improvement in MBF compared to the conventional group (P<0.001). CONCLUSIONS: 3D-printed mandibular single-implant overdentures may represent an alternative to conventionally fabricated ones.

Prevalence of body-focused repetitive behaviors in a diverse population sample - rates across age, gender, race and education.

BACKGROUND: Prevalence estimates for body-focused repetitive behaviors (BFRBs) such as trichotillomania differ greatly across studies owing to several confounding factors (e.g. different criteria). For the present study, we recruited a diverse online sample to provide estimates for nine subtypes of BFRBs and body-focused repetitive disorders (BFRDs). METHODS: The final sample comprised 1481 individuals from the general population. Several precautions were taken to recruit a diverse sample and to exclude participants with low reliability. We matched participants on gender, race, education and age range to allow unbiased interpretation. RESULTS: While almost all participants acknowledged at least one BFRB in their lifetime (97.1%), the rate for BFRDs was 24%. Nail biting (11.4%), dermatophagia (8.7%), skin picking (8.2%), and lip-cheek biting (7.9%) were the most frequent BFRDs. Whereas men showed more lifetime BFRBs, the rate of BFRDs was higher in women than in men. Rates of BFRDs were low in older participants, especially after the age of 40. Overall, BFRBs and BFRDs were more prevalent in White than in non-White individuals. Education did not show a strong association with BFRB/BFRDs. DISCUSSION: BFRBs are ubiquitous. More severe forms, BFRDs, manifest in approximately one out of four people. In view of the often-irreversible somatic sequelae (e.g. scars) BFRBs/BFRDs deserve greater diagnostic and therapeutic attention by clinicians working in both psychology/psychiatry and somatic medicine (especially dermatology and dentistry).

Measurement of voluntary bite forces in large carnivores using a semi-automated reward-driven system.

Bite force is a key performance trait of the feeding system, but maximal in vivo bite force has been measured in few large mammals. The alternative, modelling of bite force from anatomy, cannot be validated without in vivo measurements. To overcome existing limitations of ethics, safety and animal well-being, we propose a semi-automated method to obtain voluntary maximum bite forces from large mammals using bite plates that automatically dispense a food reward if an incrementally increasing threshold force value is reached. We validated our method using two Malayan sun bears, two Andean spectacled bears and a lioness. We show that voluntary bite force measurement using positive reinforcement is a non-invasive and reliable method to record maximum voluntary bite force performance in large mammals. Our results further show that in vivo data are critical as modeling efforts from osteology have greatly underestimated bite forces in Andean spectacled bears.

Effects of vegetation densities on the performance of attractive targeted sugar baits (ATSBs) for malaria vector control: a semi-field study.

BACKGROUND: Attractive targeted sugar baits (ATSBs) control sugar-feeding mosquitoes with oral toxicants, and may effectively complement core malaria interventions, such as insecticide-treated nets even where pyrethroid-resistance is widespread. The technology is particularly efficacious in arid and semi-arid areas. However, their performance remains poorly-understood in tropical areas with year-round malaria transmission, and where the abundant vegetation constitutes competitive sugar sources for mosquitoes. This study compared the efficacies of ATSBs (active ingredient: 2% boric acid) in controlled settings with different vegetation densities. METHODS: Potted mosquito-friendly plants were introduced inside semi-field chambers (9.6 m by 9.6 m) to simulate densely-vegetated, sparsely-vegetated, and bare sites without any vegetation (two chambers/category). All chambers had volunteer-occupied huts. Laboratory-reared Anopheles arabiensis were released nightly (200/chamber) and host-seeking females recaptured using human landing catches outdoors (8.00 p.m.-9.00 p.m.) and CDC-light traps indoors (9.00 p.m.-6.00 a.m.). Additionally, resting mosquitoes were collected indoors and outdoors each morning using Prokopack aspirators. The experiments included a "before-and-after" set-up (with pre-ATSBs, ATSBs and post-ATSBs phases per chamber), and a "treatment vs. control" set-up (where similar chambers had ATSBs or no ATSBs). The experiments lasted 84 trap-nights. RESULTS: In the initial tests when all chambers had no vegetation, the ATSBs reduced outdoor-biting by 69.7%, indoor-biting by 79.8% and resting mosquitoes by 92.8%. In tests evaluating impact of vegetation, the efficacy of ATSBs against host-seeking mosquitoes was high in bare chambers (outdoors: 64.1% reduction; indoors: 46.8%) but modest or low in sparsely-vegetated (outdoors: 34.5%; indoors: 26.2%) and densely-vegetated chambers (outdoors: 25.4%; indoors: 16.1%). Against resting mosquitoes, the ATSBs performed modestly across settings (non-vegetated chambers: 37.5% outdoors and 38.7% indoors; sparsely-vegetated: 42.9% outdoors and 37.5% indoors; densely-vegetated: 45.5% outdoors and 37.5% indoors). Vegetation significantly reduced the ATSBs efficacies against outdoor-biting and indoor-biting mosquitoes but not resting mosquitoes. CONCLUSION: While vegetation can influence the performance of ATSBs, the devices remain modestly efficacious in both sparsely-vegetated and densely-vegetated settings. Higher efficacies may occur in places with minimal or completely no vegetation, but such environments are naturally unlikely to sustain Anopheles populations or malaria transmission in the first place. Field studies therefore remain necessary to validate the efficacies of ATSBs in the tropics.

Seasonal assessment on the effects of time of night, temperature and humidity on the biting profile of Anopheles farauti in north Queensland, Australia using a population naive to malaria vector control pressures.

BACKGROUND: Anopheles farauti is one of the major vectors of malaria in the Southwest Pacific region and is responsible for past outbreaks in Australia. With an adaptable biting profile conducive to behavioural resistance to indoor residual spraying (IRS) and insecticide-treated nets (ITNs), its all-night biting behaviour can switch to biting mostly in the early evening. With limited insight into the biting profile of An. farauti populations in areas that have not encountered IRS or ITNs, the aim of this study was to develop insights on the biting behaviour of a malaria control naive population of An. farauti. METHODS: Biting profiles of An. farauti were conducted at Cowley Beach Training Area, in north Queensland, Australia. Initially, encephalitis virus surveillance (EVS) traps were used to document the 24-h biting profile of An. farauti and then human landing collections (HLC) were used to follow the 18.00-06.00 h biting profile. The human landing catches (HLC) were performed at both the end of the wet (April) and dry (October) seasons. RESULTS: Data exploration using a Random Forest Model shows that time of night is the most important variable for predicting An. farauti biting activity. Temperature was found to be the next important predictor, followed by humidity, trip, collector, and season. The significant effect of time of night and peak in time of night biting, between 19.00 and 20.00 h was also observed in a generalized linear model. The main effect of temperature was significant and non-linear and appears to have a positive effect on biting activity. The effect of humidity is also significant but its relationship with biting activity is more complex. This population's biting profile is similar to populations found in other parts of its range prior to insecticide intervention. A tight timing for the onset of biting was identified with more variation with the end of biting, which is likely underpinned by an endogenous circadian clock rather than any light intensity. CONCLUSION: This study sees the first record of a relationship between biting activity and the decreasing temperature during the night for the malaria vector, Anopheles farauti.

Porcine ear necrosis: characterization of lesions and associated pathogens.

Porcine ear necrosis (PEN) is characterized by ulcerative lesions of the ear auricle. To investigate that problem, three farms with PEN in nursery pigs were included, and the study aim was to characterize PEN and the potential role of pathogens and mycotoxins. Within each farm, one batch of weaned piglets was included and the prevalence and severity of PEN were monitored for 6-7 weeks. Within each batch, 30 PEN-affected/non-affected animals were randomly selected. Blood samples were taken from these animals, to assess the systemic presence of pathogens and mycotoxins, as well as punch biopsies from the ear auricle for histopathological examination. From 10 animals, scrapings and swabs from the lesions were subjected to nanopore metagenomic sequencing and bacteriological cultivation, respectively. In all three farms, lesions appeared within 3-4 weeks post-weaning. The prevalence at the end of the nursery was 33%, 24%, and 46% for farms A, B, and C, respectively. Most affected pigs had mild to moderate lesions. Blood samples revealed low to very low levels of pathogens and mycotoxins. Different bacteria such as Staphylococcus, Streptococcus, Fusobacterium, Mycoplasma, and Clostridium species were identified by sequencing in the scrapings. The first two pathogens were also most often identified in bacterial cultures. Mycoplasma hyopharyngis was only found in PEN-affected pigs. Histopathological changes were primarily observed in the outer layer of the epidermis. The results suggest that PEN lesions develop by damage to the outer part of the skin e.g. by ear suckling or biting, followed by multiplication of opportunistic pathogens.