Environmental drivers of parasite load and species richness in introduced parakeets in an urban landscape.

Introduced species represent a threat to native wildlife worldwide, due to predation, competition, and disease transmission. Concurrent introduction of parasites may also add a new dimension of competition, i.e. parasite-mediated competition, through spillover and spillback dynamics. Urban areas are major hotspots of introduced species, but little is known about the effects of urban habitat structure on the parasite load and diversity of introduced species. Here, we investigated such environmental effects on the ectoparasite load, richness, and occurrence of spillback in two widespread invasive parakeets, Psittacula krameri and Myiopsitta monachus, in the metropolitan area of Rome, central Italy. We tested 231 parakeets and found that in both species parasite load was positively influenced by host abundance at local scale, while environmental features such as the amount of natural or urban habitats, as well as richness of native birds, influenced parasite occurrence, load, and richness differently in the two host species. Therefore, we highlight the importance of host population density and habitat composition in shaping the role of introduced parakeets in the spread of both native and introduced parasites, recommending the monitoring of urban populations of birds and their parasites to assess and manage the potential occurrence of parasite-mediated competition dynamics as well as potential spread of vector-borne diseases.

Phylogenetic analysis of partial sequences of elongation factor 1alpha identifies major groups of lice (Insecta: Phthiraptera).

As a first attempt to use molecular data to resolve the relationships between the four suborders of lice and within the suborder Ischnocera, we sequenced a 347-bp fragment of the elongation factor 1alpha gene of 127 lice (Insecta: Phthiraptera) as well as outgroup taxa from the order Psocoptera. A number of well-supported monophyletic groups were found but the relationships among many of these groups could not be resolved. While it is probable that multiple substitutions at high divergences and ancient radiation over a short period of time have contributed to the problem, we attribute most of this lack of resolution to the high ratio of taxa to characters. Nevertheless, the sequence data unequivocally support a number of important relationships that are at variance with the conclusions of morphological taxonomy. These include the sister group relationship of Chelopistes and Oxylipeurus, two lice occupying different ecological niches on the same host, which have previously been assigned to different families. These results provide evidence in support of the hypothesis that lice have speciated in situ on the host in response to niche specialization and that this has given rise to convergent morphologies in the lice of different host groups which share similar ecological niches. We discuss our attempts to overcome the limitations of this large data set, including the use of leaf stability analysis, a new method for analyzing the stability of taxa in a phylogenetic tree, and examine a number of hypotheses of relationships based on both traditional taxonomy and host associations.

Preventive periimplant protocol.

The primary responsibility of the clinician treating a patient with implant dentistry is to provide a long-term favorable prognosis. In consideration of changes in implant materials and restorative designs, familiarity with the relationship of the periimplant tissues to the implant components is essential. Maintaining healthy tissues requires understanding the influence of the intraoral bacterial flora, recognizing deviations from health, and initiating an appropriate preventive protocol. Various implements that are available for plaque control and debridement are discussed.

Hyperinsulinaemic hypoglycaemia in an infant with mosaic trisomy 13.

An infant with mosaic trisomy 13, who was small for gestational age, became severely hypoglycaemic. For the first 19 days of life, glucose requirements to maintain normoglycaemia were high (up to 21.7 mg/kg/min) and at the same time the infant had high plasma insulin levels and low glucose insulin ratios. Treatment with hydrocortisone and susphrine was of questionable benefit. Hyperinsulinism abated by the third week of life. This case illustrates early remission of hyperinsulinaemic hypoglycaemia and raises the possibility of an association with trisomy 13.

Intussusception associated with necrotizing enterocolitis.

Two premature infants whose clinical picture initially was that of necrotizing enterocolitis eventually developed intussusception. The symptomatology of these two conditions is similar, and when they coexist, recognition of a complicating intussusception is difficult. The pathogenic relationship between necrotizing enterocolitis and intussusception remains obscure. The possibility that necrotizing enterocolitis can be a leading point in the development of intussusception is discussed.