Emergence of behavioural avoidance strategies of malaria vectors in areas of high LLIN coverage in Tanzania.

Despite significant reductions in malaria transmission across Africa since 2000, progress is stalling. This has been attributed to the development of insecticide resistance and behavioural adaptations in malaria vectors. Whilst insecticide resistance has been widely investigated, there is poorer understanding of the emergence, dynamics and impact of mosquito behavioural adaptations. We conducted a longitudinal investigation of malaria vector host choice over 3 years and resting behaviour over 4 years following a mass long-lasting insecticidal nets (LLINs) distribution in Tanzania. By pairing observations of mosquito ecology with environmental monitoring, we quantified longitudinal shifts in host-choice and resting behaviour that are consistent with adaptation to evade LLINs. The density of An. funestus s.l., declined significantly through time. In tandem, An. arabiensis and An. funestus s.l. exhibited an increased rate of outdoor relative to indoor resting; with An. arabiensis reducing the proportion of blood meals taken from humans in favour of cattle. By accounting for environmental variation, this study detected clear evidence of intra-specific shifts in mosquito behaviour that could be obscured in shorter-term or temporally-coarse surveys. This highlights the importance of mosquito behavioural adaptations to vector control, and the value of longer-term behavioural studies.

Investigating associations between biting time in the malaria vector Anopheles arabiensis Patton and single nucleotide polymorphisms in circadian clock genes: support for sub-structure among An. arabiensis in the Kilombero valley of Tanzania.

BACKGROUND: There is growing evidence that the widespread use of Long-Lasting Insecticidal Nets (LLINs) is prompting malaria vectors to shift their biting towards times and places where people are not protected, such as earlier in the evening and/or outdoors. It is uncertain whether these behavioural shifts are due to phenotypic plasticity and/or ecological changes within vector communities that favour more exophilic species, or involve genetic factors within vector species to limit their contact with LLINs. Possibly variation in the time and location of mosquito biting has a genetic basis, but as yet this phenomenon has received little investigation. Here we used a candidate gene approach to investigate whether polymorphisms in selected circadian clock genes could explain variation in the time and location of feeding (indoors versus outside) within a natural population of the major African malaria vector Anopheles arabiensis. METHODS: Host-seeking An. arabiensis were collected from two villages (Lupiro and Sagamaganga) in Tanzania by Human Landing Catch (HLC) technique. Mosquitoes were classified into phenotypes of "early" (7 pm-10 pm) or "late" biting (4 am -7 am), and host-seeking indoors or outdoors. In these samples we genotyped 34 coding SNPs in 8 clock genes (PER, TIM, CLK, CYC, PDP1, VRI, CRY1, and CRY2), and tested for associations between these SNPs and biting phenotypes. SNPs in 8 mitochondrial genes (ATP6, ATP8, COX1, COX2, COX3, ND3, ND5 and CYTB) were also genotyped to test population subdivision within An. arabiensis. RESULTS: The candidate clock genes exhibited polymorphism within An. arabiensis, but it was unrelated to variation in the timing and location of their biting activity. However, there was evidence of strong genetic structure within An. arabiensis populations in association with the TIM, which was unrelated to geographic distance. Substructure within An. arabiensis was also detected using mitochondrial markers. CONCLUSIONS: The variable timing and location of biting in An. arabiensis could not be linked to candidate clock genes that are known to influence behaviour in other Diptera. This finding does not rule out the possibility of a genetic basis to biting behaviour in this malaria vector, but suggests these are complex phenotypes that require more intensive ecological, neuronal and genomic analyses to understand.

Biocompatibility of single-walled carbon nanotube composites for bone regeneration.

OBJECTIVES: The purpose of this study was to evaluate in vivo biocompatibility of novel single-walled carbon nanotubes (SWCNT)/poly(lactic-co-glycolic acid) (PLAGA) composites for applications in bone and tissue regeneration. METHODS: A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight and 12 weeks post-implantation were compared with control (Sham) and PLAGA (five rats per group/point in time). Rats were observed for signs of morbidity, overt toxicity, weight gain and food consumption, while haematology, urinalysis and histopathology were completed when the animals were killed. RESULTS: No mortality and clinical signs were observed. All groups showed consistent weight gain, and the rate of gain for each group was similar. All groups exhibited a similar pattern for food consumption. No difference in urinalysis, haematology, and absolute and relative organ weight was observed. A mild to moderate increase in the summary toxicity (sumtox) score was observed for PLAGA and SWCNT/PLAGA implanted animals, whereas the control animals did not show any response. Both PLAGA and SWCNT/PLAGA showed a significantly higher sumtox score compared with the control group at all time intervals. However, there was no significant difference between PLAGA and SWCNT/PLAGA groups. CONCLUSIONS: Our results demonstrate that SWCNT/PLAGA composites exhibited in vivo biocompatibility similar to the Food and Drug Administration approved biocompatible polymer, PLAGA, over a period of 12 weeks. These results showed potential of SWCNT/PLAGA composites for bone regeneration as the low percentage of SWCNT did not elicit a localised or general overt toxicity. Following the 12-week exposure, the material was considered to have an acceptable biocompatibility to warrant further long-term and more invasive in vivo studies. Cite this article: Bone Joint Res 2015;4:70-7.

Adverse local reactions to amethocaine cream--audit and case reports.

Amethocaine has recently been introduced as a topical local anaesthetic preparation. Following sporadic reports of severe local adverse effects, we conducted an audit of 372 children attending our hospital for day surgery. We conclude that 4% amethocaine cream is a safe and effective topical anaesthetic and that the incidence of severe local adverse reactions is rare. We also report two of these local reactions, one involving occupational exposure.

An analysis of residual deformity in club feet submitted to early operation.

The contributions made by metatarsus primus varus, medial subluxation of the navicular, and angulation of the neck of the talus to the residual deformity in treated club feet were assessed from radiographs. Their relation to the appearance of the feet, to the age of the patient, to the results of operations, and to the age at the time of the first operation were investigated. Lateral rotation of the ankle and flattening of the talus were also studied. Medial subluxation of the navicular was found to be the most important factor influencing both the appearance of the feet and the lateral rotation of the ankle. Relocation of the talonavicular joint correlated with the success of operative treatment; and the timing of the primary operation determined the degree of relocation which could be achieved. Metatarsus primus varus and angulation of the talus were of little importance. Increased emphasis is given to the need for early relocation of the talonavicular joint.

The results of early operation in talipes quino-varus. A preliminary report.

The results of operation performed within the first six months of life upon seventy-seven resistant club feet are presented. The indications for and the rationale of early operation are discussed. Particular attention has been paid to the relationship between the age at operation and the outcome more than four years later; the results were greatly superior when operation was undertaken early. Two surgical techniques are compared, the postero-medial release proving better than a simple posterior release. The relationship between clinical and radiological assessment is discussed, and also the influence of the results reported upon future practice.

Injuries of the midtarsal joint.

Injuries involving the midtarsal joint, which are frequently misdiagnosed, have been studied to clarify the mechanism, classification and treatment. The necessity for routine antero-posterior, lateral and oblique radiographs is emphasised. Seventy-one injuries have been classified according to the direction of the deforming force:medial, longitudinal compression, lateral, plantar and crush types are described. Included in the medial and lateral types is a hitherto undescribed tarsal rotation or "swivel" injury. The mechanism whereby longitudinal compression causes fractures of the body of the navicular is described, and two varieties having different prognoses are defined: one due to purely longitudinal compression and the other due to longitudinal compression with a medial component. The results of treatment have been assessed clinically and radiologically. Reduction, open if necessary, with internal fixation, is recommended for displace fractures: primary arthrodesis is not indicated. For severe persistent symptoms from medial and longitudinal force injuries triple arthrodesis is recommended, and from lateral force injuries, calcaneo-cuboid arthrodesis.