Review of health economic models exploring and evaluating treatment and management of hospital-acquired pneumonia and ventilator-associated pneumonia.

BACKGROUND: Hospital-acquired pneumonia (HAP) is pneumonia that occurs ≥48 h after hospital admission; it is the most common hospital-acquired infection contributing to death. Ventilator-associated pneumonia (VAP) arises ≥48-72 h after intubation. Opinions differ on whether VAP is a subset of HAP; the same pathogens predominate in both. Compared with VAP-free controls, patients developing VAP are twice as likely to die and have significantly longer stays in intensive care units. Guidelines recommend that microbiological cultures should guide antibiotic treatment, but these lack sensitivity and take 48-72 h to process, meaning that initial therapy must be empiric, generally with broad-spectrum agents. Given increasing pressure to improve both antibiotic stewardship and patient outcomes, the National Institute for Health and Care Excellence and the Infectious Diseases Society of America recommend research into rapid molecular diagnostic tests to identify causative organisms and their antibiotic resistances. Ideally, these would supersede culture, being quicker and more sensitive. In the UK, the INHALE research programme, funded by the National Institute for Health Research, is exploring rapid molecular diagnostics to inform treatment of HAP/VAP and, given resource implications, incorporates a health economic component. AIM: To identify previous economic modelling of HAP/VAP costs to inform this component. METHODS: Literature review of HAP/VAP studies with economic modelling identified from three databases. FINDINGS: Twenty studies were identified. Only one study specifically evaluated strategies to improve diagnosis; the remaining 19 studies omitted this important aspect. CONCLUSION: HAP/VAP modelling would be improved by better awareness of long-term outcomes and treatment complexity. To the authors' knowledge, no similar literature reviews of economic modelling for HAP/VAP have been published.

A European consensus for the evaluation and management of infants with an equivocal diagnosis following newborn screening for cystic fibrosis.

Screening newborns for cystic fibrosis (CF) is considered to be an ethical undertaking in regions with a significant incidence of the condition. Current screening protocols result in recognition of infants with an equivocal diagnosis. A survey of European practice suggested inconsistencies in the evaluation and management of these infants. We have undertaken a consensus process using a modified Delphi method. This has enabled input of CF specialists from a wide geographical area to a rigorous process that has provided a clear pathway to a consensus statement. A core group produced 21 statements, which were modified over a series of three rounds (including a meeting arranged at the European CF Conference). A final document of 19 statements was produced, all of which achieved a satisfactory level of consensus. The statements cover four themes; sweat testing, further assessments and investigations, review arrangements and database. This consensus document will provide guidance to CF specialists with established screening programmes and those who are in the process of implementing newborn screening in their region.

A survey of current practice with regard to oral care for children being treated for cancer.

The aim of the study was to establish current UK oral care practice for children with cancer. A telephone survey of all 22 United Kingdom Children's Cancer Study Group (UKCCSG) centres was undertaken. Nineteen (86%) of the centres reported using guidelines/protocols for mouth care. The use of routine preventive oral care therapies showed the greatest variation between centres. Four centres (18%) did not use any prophylactic oral care therapy other than basic oral hygiene, whereas seven (32%) routinely used a combination of three or more agents. Chlorhexidine was the most frequently administered prophylactic therapy (17/22 centres, 77%), followed by nystatin (11/22 centres, 50%). There was little variation in advice given to parents/patients on basic oral hygiene. Regarding dental check-ups, 9/22 centres (41%) recommended children to attend a hospital-linked dental clinic. Only at 8/22 centres (36%) did children undergo a dental check-up before commencing cancer treatment. The survey identified significant variation in preventive oral care therapies and dental check-ups at the UKCCSG centres. Attention needs to be given to establishing evidence based, effective strategies.

Reproductive development in young boars exposed to sexually mature, nonpregnant sows and gilts.

Thirty Yorkshire boars were allotted by litter to one of two treatment groups. Fifteen boars were reared, from 14 to 22 wk of age, in fenceline contact with mature sows and gilts that were randomly exhibiting estrus. Fifteen littermates of these boars, reared without exposure to females, served as controls. Boar-to-boar sexual behaviors were observed 1 hour daily from 16 to 22 wk of age. At ages 14 to 30 wk, boars were weighed at 4-wk intervals. Five boars per treatment were slaughtered when 22 wk old and twelve others (six per treatment) when 30 wk old. Vesicular gland, bulb of the prostate gland, bulbourethral gland, and each testis, cauda epididymis, and combined caput and corpus epididymis were closely trimmed and weighed. Left cauda epididymal sperm and left testis elongated spermatids were determined by homogenization and hemacytometer counting. At 26, 30, and 38 wk of age, boars were tested for mating efficiency by exposure to an estrous gilt. Boars exposed to females tended to be lighter at 22 wk and were lighter at 30 wk (P<.05). Total male-to-male sexual acts from 16 to 22 wk were correlated with mating-efficiency score at 26 and 30 wk (r = .69 and .68, respectively; (P<.05)). Correlation between testicle size and total testicle elongated spermatids was high at 30 wk of age (r = .92; P<.001). Results indicated that exposing young boars to mature females had limited effects on the boars' reproductive development; however, there were strong indications of a relationship between boar behavior during rearing and postpuberal mating performance.

Measuring social behavior: social dominance.

Social dominance develops more slowly when young animals are kept in intact peer groups where they need not compete for resources. Learned generalizations may cause smaller and weaker animals to accept subordinate status readily when confronted with strangers that would be formidable opponents. Sexual hormones and sensitivity to them can influence the onset of aggression and status attained. After dominance orders are established, they tend to be stable in female groups but are less so in male groups. Psychological influences can affect dominance relationships when strangers meet and social alliances within groups may affect relative status of individuals. Whether status associated with agonistic behavior is correlated with control of space and scarce resources needs to be determined for each species and each kind of resource. When such correlations exists, competitive tests and agonistic behavior associated with gaining access to scarce resources can be useful to the observer in learning about dominance relationships rapidly. Examples are given to illustrate how estimates of social dominance can be readily attained and some strengths and weaknesses of the various methods.

Mating behavior, boar-to-boar behavior during rearing and soundness of boars penned individually or in groups from 6 to 27 weeks of age.

Individual and group-reared boars were compared in two experiments, for treatment effects on mating behavior, growth rate, feed consumption and feed/gain. Soundness also was evaluated in one experiment. Boar-to-boar behaviors were studied in group-penned boars. In Exp. 1, boars were either reared in a group of five or individually from 12 to 27 wk of age, or group-penned from 12 to 19 wk and individually from 1-9 wk. In Exp. 2, boars were either penned individually from 6 to 27 wk, group-penned (eight/pen) from 6 to 27 wk, grouped from 6 to 12 wk and then penned individually, or individually penned from 6 to 12 wk and then group-penned. Beginning at 29 wk of age, boars were tested every 2 wk for mating behavior in the presence of an estrous gilt. Four mating tests were conducted in Exp. 1 and five tests in Exp. 2. Individually penned boars grew faster from 6 to 12 wk old in Exp. 2, but no other treatment effects on growth rate were observed. Treatment had very little effect on mating test behaviors, but individual penning markedly reduced leg soundness. Sheath sniffing first appeared at 16 to 18 wk of age in group-penned boars and was followed closely by anal sniffing. Side nosing increased between 20 and 23 wk. Mounting activity from 12 to 27 wk old was correlated with mating test score in Exp. 1 (.76; P less than .01) and Exp. 2 (.55; P less than .05).

Effects of feeding systems on social and feeding behavior and performance of finishing pigs.

Two experiments were conducted to study the effects of feeding systems on feeding behavior, aggression, social ranks and average daily gain (ADG) of pigs. In Exp. 1, feed was delivered during the day from 1100 to 1400 and at night from 2300 to 0200. One pen containing 10 barrows and 10 gilts was used. Correlation coefficients were calculated between pairs of traits. In Exp. 2, four feeding systems were tested using similar group composition as in Exp. 1. Two feeding systems were ad libitum, offering either dry or wet feed; the other two used time-restricted feeding from 0900 to 1100 and from 1600 to 1800, but with water supplied either ad libitum or time-restricted. Analyses of variance were used to test feeding system effects; correlation coefficients were calculated for pairs of traits. Results of Exp. 1 indicated that pigs displayed predominantly daytime activities. Frequency of aggressive acts were correlated significantly with feeding frequency (r = .48), time to first feeding (r = -.50) and ADG (r = .56). In Exp. 2, pigs on time-restricted feeding with ad libitum water had significantly depressed ADG and reduced feed intake. A possible association between time-restricted feeding and water intake is postulated. Feeding behavior, aggression and social rank were associated with ADG in time-restricted systems but not in ad libitum systems. There was a tendency in time-restricted-fed pigs for the more aggressive pigs to perform more feeding activities, to rank higher in the social order, and to gain faster.

The effect of rearing environment on sexual behavior of young beef bulls.

Fifty-eight Polled Hereford bull calves were weaned at an average age of 196 d. They were penned individually after weaning and contact was limited to fenceline exposure to bulls in adjacent pens, except when grouped for weighing every 28 d. Six months after weaning they were allotted to one of the following 10-wk rearing treatments: 1) individually penned; 2) individually penned, but exposed to a heifer in estrus for 30 min every 2 wk; 3) group penned; 4) group penned, but each bull exposed to a heifer in estrus for 30 min every 2 wk. The week after allotment was designated wk 0. All 58 bulls, penned together after wk 12, had single-bull mating tests during wk 10, 22 and 32 and multi-bull mating tests during wk 12, 24 and 34. Mean serving capacity and mean serving efficiency were both greater (P less than .05) for individually-penned bulls than for group-penned bulls during the first single-bull and the first multi-bull mating test. No significant serving-capacity differences were present in subsequent single-bull or multi-bull mating tests, but serving efficiency was greater (P less than .05) for group-penned bulls in all subsequent tests, except the last multi-bull mating test. Mean serving capacity was greater (P less than .05), as was mean serving efficiency (P less than .01), for bulls in single-bull mating tests than for those in multi-bull tests. Exposure to heifers during rearing did not affect libido or mating ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Beak trimming effects on behavior patterns, fearfulness, feathering, and mortality among three stocks of White Leghorn pullets in cages or floor pens.

White Leghorn pullets of the Y1, Y2, and North Central Randombred (NCR) experimental stocks were used. Half of the birds of each stock had half of the upper and less of the lower mandible removed at 4 wk of age by making a V-shaped cut as viewed from the side (BT), whereas the other half retained their beaks intact (IN). Pullets were moved from growing pens to a layer house at 18 wk of age. Seventy-two cages and 30 floor pens were filled with 6 and 20 birds per unit, respectively. Pullets within a cage or floor pen were all of the same genetic stock and beak treatment. All measurements were performed within 10 wk after housing, except for mortality in cages. When kept in cages, genetic stocks did not show behavioral differences. However, in floor pens, stock differences were detected in feeding, crouching, and nonaggressive pecking. When kept in cages, the stocks also differed in 24-wk body weight, weight gain from 18 to 24 wk, and certain measures of fearfulness in both cages and pens, and in feather condition at 21 and 22 wk. Mortality from cannibalism and hen-days survival of caged IN pullets differed among genetic stocks. Mortality from cannibalism was absent among pullets kept in experimental floor pens. In cages, BT pullets were less active, gained less weight, and had lower incidence of cannibalism than IN pullets. Also, BT pullets were less nervous and had better feather condition than IN pullets. However, trimming beaks to prevent cannibalism was less effective in NCR pullets than in Y1 or Y2 pullets. In floor pens, BT pullets showed less activity and reduced feeding frequency and less fearfulness as indicated by duration of induced tonic immobility. Agonistic behaviors were not different between BT and IN pullets. From these results, beak trimming could be interpreted as having either stressful or stress-alleviating effects, depending on the criteria used. However, proper beak trimming appears beneficial when cannibalistic pecking is likely to be a problem. The relative benefits of beak trimming vary among genetic stocks.

Review: welfare perspectives on hens kept for egg production.

The wild ancestors of chickens, along with those of most other farm animals, were preadapted to domestication because their lack of specialized requirements allowed them to adapt to a wide variety of environments provided by humans. Currently most commercial chickens kept for table-egg production are incubated, reared, and maintained as productive adults in high-density, artificial environments. Nevertheless, there are limits to adaptability as indicated by behavioral, physiological, immunological, and individual productivity indicators when environmental conditions become extreme. However, with the exception of obvious injury, no single criterion is likely to be adequate. Multiple indicators are required to obtain reliable evaluation of whether husbandry practices and environmental conditions reduce hens' welfare significantly. Concern for the well-being of hens has led to the phasing out of cages in two European countries. Although cages are known to be associated with some problems of well-being, it is known also that they have some welfare advantages for hens over alternative systems of production and they have definite economic advantages for producers. Therefore, it is doubtful whether the use of cages should be denied without exploring further the possibilities of cage modification or genetic selection aimed at improving the well-being of hens in such environments. Ethical perspectives relative to animals have been evolving since the time of Aristotle more than 300 yr B.C. Recent developments include divergence of welfare concerns between utilitarian and animal rights based philosophies. The utilitarians generally agree that animals may be used for human benefit if unnecessary pain and suffering are avoided and humane care and management criteria are met. Fundamentally, rights-oriented groups reject such exploitation. The general public exhibits a continuum of attitudes towards animals. However, there are indications that they are moving towards a protectionist attitude toward farm animals. Many requirements for good husbandry are known. However, uncertainty prevails in some areas, particularly with the necessity of routine procedures such as beak trimming and the amount of space needed, optimal group size, and whether nests, roosts, litter, and other quality of environment features are necessities or luxuries in terms of hens' welfare. Floor and feeder space and group size seem to be of paramount importance, and space that is adequate for well-being seems to be greater than that which yields the greatest net income. Genetic solutions to several behavior-related problems that compromise hens' well-being seem to be feasible and worthy of greater emphasis by commercial poultry breeders.

Improving animal well-being through genetic selection.

This paper reviews the possibilities of adapting laying hens to cages by means of genetic selection. By selecting separately for rate of lay and longevity using a kin selection method, a strain of laying hen has been developed that shows much less feather pecking and cannibalism than a control strain, and with no decrease in productivity. This experimental strain enjoys a higher level of welfare in cages because it does not require beak trimming.

Group selection for adaptation to multiple-hen cages: beak-related mortality, feathering, and body weight responses.

The hypothesis was tested that selection on the basis of family means for increased survival and hen-housed egg production, when sisters with intact beaks were kept together in multiple-bird cage, would cause adaptive changes in behavior. Specifically, it was posited that beak-inflicted injuries causing cannibalistic mortality and feather loss and damage would be reduced. Body weight effects were not predicted, but were examined. Three stocks were compared; the Selected (S), representing the seventh generation of selection, the Randombred Control (C) from which S was derived, and a commercial stock (X), known to be highly productive and peak-trimmed by commercial producers. Pullets were placed in single-bird (1H) as well as in 12-hen (12H) cages using a completely randomized block experimental design. Mortality from beak-inflicted injuries differed among stocks in total hens lost (P < 0.005). Of 576 per stock in 12H cages 287, 128, and 46 replacements were used from 17 to 44 wk in X, C, and S, respectively, to maintain group size. The C and S hens also differed from 44 to 59 wk and 17 to 59 wk. X hens were not included in comparisons of mortality beyond 44 wk. Relative incidence of mortality caused by vent-cloacal injuries differed with X > C = S (P < 0.005 for X vs C and S). For cages with > or = 1 cannibalistic death, X had twice (P < 0.025) and C 1.6 times (P < 0.10) as many with repeated losses as S. Means and variances of feather scores were different for 1H vs 12H cages, ages, and genetic stocks. Greater variances were observed in 12H cages and among older birds. Within 1H units, genetic stocks did not differ in general, but in 12H cages X and C were always more variable than S. In 12H cages, mean feather scores and body weights were decreased and S hens had better feathering than either C or X. The evidence supported the hypothesis.

Group selection for adaptation to multiple-hen cages: behavioral responses.

Three stocks of White Leghorns were compared for behavioral traits when kept in single-bird (1H) and 12-hen (12H) layer-house cages. Genetic stocks consisted of a commercial strain (X), a randombred control (C), and a stock derived from C and selected on the basis of kin's group performance information for increased survival and egg production over seven generations (S). Experimental units consisted of four consecutive 1H cages or a single 12H cage. All birds within a unit had intact beaks and were of the same stock. Each stock was represented by hens in 48 units of both 1H and 12H cages, and by 48 males (C and S stocks only) in 1H cages. Birds that died were replaced. Observations involved hens in their home cages except for tonic immobility (TI) and pair contests. Observations carried out soon after birds were placed in layer-house cages indicated that avoidance of the observer was essentially absent after pullets were observed on the 1st and 2nd d. Behavioral profile frequencies differed for nearly all behaviors compared in 1H and 12H environments. Following initially high crouching and low feeding frequencies, apparently normal levels were present by Days 15 and 16 posthousing. During the initial adaptation phase, genetic stock differences were not found within 1H cages and were present in only 2 of 10 categories in 12H cages. Young adult profiles also indicated no differences among stocks in 1H cages, but stock differences were found in 6 of 12 categories in 12H cages. In those cases, X strain hens differed from hens of the C and S stocks, but C and S hens did not differ from each other. Comparisons carried out between hens in 1H and 12H cages revealed that fearfulness was greater in 12H cages. Genetic stock comparisons, involving relative fearfulness and feeding and movement in a frustrating situation indicated that the X stock frequently differed from both C and S, but C and S did not usually differ from each other. However, observations of hens' agonistic activity in the 12H home cage environment revealed that the S stock had fewer agonistic acts than the C stock from which it was derived, and both C and S had less agonistic activity than the X stock. Pair contests carried out within and between C and S stocks in both sexes yielded results inconsistent with those for agonistic activity in 12H cages. The C and S hens did not differ, but S males were more aggressive and, in between-strain contests, were more dominant.

Research note: genetic adaptation to multiple-bird cage environment is less evident with effective beak trimming.

Selection of hens with intact beaks for high performance in multiple-bird cages has produced a stock that clearly exceeds its unselected control when hens have intact beaks but shows less advantage when comparisons involve effectively beak-trimmed birds. The selected stock performed at about the same level as a stock recently derived from a commercial source (but with two generations of relaxed selection) when birds had intact beaks but at a lower level when birds had their beaks trimmed. Relative incidences of deaths from cannibalistic pecking were partially responsible for the results obtained.

Fertility from natural matings influenced by social and physical environments in multiple-bird cages.

Various social and physical environments were tested for effects on fertility using three White Leghorn strains in multiple-bird cages. Familiarizing breeder males with the cage environment before introducing females had no appreciable effect. Area per bird (560 vs. 1130 cm.-2) and cage height (40 vs. 80 cm.) were not detected as significant variables. Firmer wire flooring and previous mating experience of males appeared to confer advantages in establishing fertility.

Reproductive performance of three strains of chickens in colony-cage and floor-pen environments.

Genetic strains, ages, and housing environments were studied for their effects of egg production, gains in weight and fertility over an eight-week interval. Rate of egg production in small floor pens was clearly superior to that in high-density, commercial type colony cages. Fertility was influenced by all major variables and by interactions among some of them. One genetic stock was clearly superior to two others. Differences between strains were more clearly evident in the rigorous colony-cage environment than in floor pens. Fertility in colony cages was lower than in floor pens over the eight-week test, but the difference decreased with time. Young males had higher fertility than older ones.

Corticosteroid levels in white Leghorn hens as affected by handling, laying-house environment, and genetic stock.

Correlation coefficients between handling time and plasma corticosteroid concentration of White Leghorn hens were minimal when times varied from 43 to 161 sec (r = .17; P less than .05, df = 244), and no association was found when blood collection times exceeding 90 sec were omitted (r = -.02, df = 219). Handling times carried to specific endpoints of 30 and 60 sec indicated no difference, but times of 60, 120, 180, and 600 sec were associated with highly significant differences in corticosteroid levels that were inconsistent between genetic stocks. Strains selected for increased part-year egg mass responded less rapidly to handling than did unselected control strains. Confinement of hens for 4 to 6 hr in nests within their own pens caused increases of greater than 30% in corticosteroids as compared to samples obtained from hens caught directly from the floor. Neither floor pen vs. colony cage nor genetic stock differences were found for plasma corticosteroid levels of hens at a mean age of 55 weeks. Adrenocorticotropic hormone stimulation of 63-week-old hens caused an 8.5-fold increase in corticosteroids above basal but failed to elicit differential effects associated with environments or genetic stocks. Nevertheless, hens kept in floor pens had 10.8% higher survival in the laying house and exceeded colony-cage hens by more than 40% in hen-day egg mass for the final 10 weeks of a 40-week laying period.

Agonistic and nonagonistic behaviors of pullets of dissimilar strains of White Leghorns when kept separately and intermingled.

Agonistic and nonagonistic behaviors were compared for pullets of two white Leghorn strains. One strain had been selected for part-year egg production; the other was the unselected control from which the selected strain was derived. There were two experiments in which the strains were kept separately and intermingled in laying-house floor pens. The selected strain had social dominance over the control at 5 months (before sexual maturity), but that dominance had diminished or disappeared when strangers of the two strains were placed together at 17 months. Nevertheless, because of social inertia, selected strain pullets maintained undiminished dominance over control pullets for the entire laying year when they were kept together from housing time onward. Selected strain females had more aggressive acts, more feeding activity, and spent less time resting than control females in both separated- and intermingled-strain housing environments. When pullets of the two strains were kept together, the relative frequencies of their agonistic behaviors were changed, but nonagonistic activities were not altered. Pullets had increased frequencies of pecking and fighting, but not of chases and threats, when they were hungry and feeding. Pullets with higher social status had more feeding activity when feed was constantly available, but that was not apparent when all were hungry and feeding. Preening activity increased as pullets aged.

Fear-related behavior of hens in cages: effects of rearing environment, age, and habituation.

At 18 weeks, pullets reared in floor pens and cages were placed in cages designed for laying hens. Tests were conducted for escape and avoidance behavior and for duration of tonic immobility at 23 and 40 weeks of age. Rearing environment effects were not detected for either measure. Paired comparisons did not reveal effects of age or habituation on duration of induced tonic immobility.

Replacing hens in cages: effect on subsequent egg production.

Comparisons were made to determine whether replacing hens that died in multiple-hen cages would alter the subsequent well-being of such groups, as indicated by rate of egg production. In only one of four comparisons was a significantly lower rate of lay obtained from hens in cages that received replacements in the 1st 5-wk period following replacements. Differences were not detected during the 2nd 5-wk period in any of the four comparisons. Consequences of replacing vs. not replacing hens are discussed briefly.