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Prevalence of skin sores and scabies in remote Australian Aboriginal communities remains unacceptably high, with Group A Streptococcus (GAS) the dominant pathogen. We aim to better understand the drivers of GAS transmission using mathematical models. To estimate the force of infection, we quantified the age of first skin sores and scabies infection by pooling historical data from three studies conducted across five remote Aboriginal communities for children born between 2001 and 2005. We estimated the age of the first infection using the Kaplan–Meier estimator; parametric exponential mixture model; and Cox proportional hazards. For skin sores, the mean age of the first infection was approximately 10 months and the median was 7 months, with some heterogeneity in median observed by the community. For scabies, the mean age of the first infection was approximately 9 months and the median was 8 months, with significant heterogeneity by the community and an enhanced risk for children born between October and December. The young age of the first infection with skin sores and scabies reflects the high disease burden in these communities.
General Practitioner consultation rates for influenza-like illness (ILI) are monitored through several geographically distinct schemes in the UK, providing early warning to government and health services of community circulation and intensity of activity each winter. Following on from the 2009 pandemic, there has been a harmonization initiative to allow comparison across the distinct existing surveillance schemes each season. The moving epidemic method (MEM), proposed by the European Centre for Disease Prevention and Control for standardizing reporting of ILI rates, was piloted in 2011/12 and 2012/13 along with the previously proposed UK method of empirical percentiles. The MEM resulted in thresholds that were lower than traditional thresholds but more appropriate as indicators of the start of influenza virus circulation. The intensity of the influenza season assessed with the MEM was similar to that reported through the percentile approach. The MEM pre-epidemic threshold has now been adopted for reporting by each country of the UK. Further work will continue to assess intensity of activity and apply standardized methods to other influenza-related data sources.
An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI −6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group.
Aim: To describe the recruitment, ophthalmic examination methods and distribution of ocular biometry of participants in the Norfolk Island Eye Study, who were individuals descended from the English Bounty mutineers and their Polynesian wives. Methods: All 1,275 permanent residents of Norfolk Island aged over 15 years were invited to participate, including 602 individuals involved in a 2001 cardiovascular disease study. Participants completed a detailed questionnaire and underwent a comprehensive eye assessment including stereo disc and retinal photography, ocular coherence topography and conjunctival autofluorescence assessment. Additionally, blood or saliva was taken for DNA testing. Results: 781 participants aged over 15 years were seen (54% female), comprising 61% of the permanent Island population. 343 people (43.9%) could trace their family history to the Pitcairn Islanders (Norfolk Island Pitcairn Pedigree). Mean anterior chamber depth was 3.32mm, mean axial length (AL) was 23.5mm, and mean central corneal thickness was 546 microns. There were no statistically significant differences in these characteristics between persons with and without Pitcairn Island ancestry. Mean intra-ocular pressure was lower in people with Pitcairn Island ancestry: 15.89mmHg compared to those without Pitcairn Island ancestry 16.49mmHg (P = .007). The mean keratometry value was lower in people with Pitcairn Island ancestry (43.22 vs. 43.52, P = .007). The corneas were flatter in people of Pitcairn ancestry but there was no corresponding difference in AL or refraction. Conclusion: Our study population is highly representative of the permanent population of Norfolk Island. Ocular biometry was similar to that of other white populations. Heritability estimates, linkage analysis and genome-wide studies will further elucidate the genetic determinants of chronic ocular diseases in this genetic isolate.
The current paper presents information from a survey of the practices associated with the control of ectoparasites on sheep in Northern Ireland in 2005, including the estimated total quantities of pesticide active ingredients used. It also provides comparative data to that obtained from previous surveys in 1981 (Jess & Marks 1986), 1988 (Foy et al.1995) and 1997 (Jess et al.2000). The total number of sheep farms in Northern Ireland decreased by 25% to 8822 farms with a consequent 26% reduction in total sheep population to 2·1 million sheep compared with the previous survey in 1997. During this period, the number of sheep treated for ectoparasites decreased by 40%. The total quantity of organophosphorus (OP) compounds used for ectoparasite control decreased by approximately 67%, from 7·8 tonnes in 1997 to 2·6 tonnes in 2005, during which an estimated 0·38 of all sheep treated for ectoparasites received the OP active ingredient diazinon. The survey results indicate a decline in the practice of plunge-dipping sheep for ectoparasite control with the proportion of farms using this treatment method decreasing from 0·58 to 0·16 between 1997 and 2005. In 1997, an estimated 0·8 of all sheep treated for ectoparasites in Northern Ireland were plunge-dipped, which reduced significantly to 0·28 during 2005. Conversely, the use of alternative methods has increased with pour-on formulations of insecticides, macrocyclic lactones and growth regulators being applied to 0·33 of all sheep treated in 2005 compared with 0·09 in 1997. Use of intramuscular or subcutaneous injections of macrocyclic lactones for ectoparasite control has also increased to 0·24 of all sheep treated in 2005 compared with 0·1 in 1997. The proportion of sheep treated in communal spray showers also increased from 0·01 in 1997 to 0·14 in 2005. Control of blowfly maggots (Lucilia spp.) and prevention of sheep scab (Psoroptes ovis) were the main reasons given by farmers for sheep treatments. On the farms that plunge-dipped, an estimated 0·68 of surplus dip wash was disposed of immediately after dipping took place, with 0·8 of farms emptying the dipping tanks using a vacuum tanker and 0·54 spreading the surplus dip wash directly onto land. An estimated 0·35 of these farmers mixed the dip wash with slurry pre-disposal. The survey suggests that the products used for spray showers are those recommended for plunge-dipping as there are no contemporary products recommended for use in spray showers. Macrocyclic lactone injections recorded in the survey had the dual function of controlling both endo- and ectoparasites.
This review deals with the problems faced by those monogenean (platyhelminth) parasites that attach themselves to fish skin. The structure of the skin and the ways in which the posterior hook-bearing haptor achieves virtually permanent attachment to the skin are considered. Small marginal hooklets are specialized for attachment to superficial host epidermal cells, finding anchorage in the terminal web of keratinous tonofilaments, while large hooks (hamuli) may penetrate into and lodge in the collagenous dermis. The complementary roles of suction and sticky secretions in haptor attachment and the role of the pharynx in temporary attachment during feeding are also considered. During leech-like locomotion the haptor is briefly detached and, at this critical time, the anterior end is strongly fixed to the wet, current-swept and possibly slimy skin by a sticky secretion. This secretion is deployed on paired pads or discs, the latter sometimes backed up by suction. After attachment by the haptor is re-established, the special tegument covering the anterior adhesive areas may be instrumental in their instant release. The role of fish skin in the phenomenon of host specificity and in the generation of a defensive response against monogeneans is considered and site-specificity of parasites on the host's body is discussed. Possible selection pressures exerted by predatory ‘cleaner’ organisms are briefly evaluated.
The monogenean (platyhelminth) skin parasite Entobdella soleae
from the common sole (Solea solea) lays tetrahedral eggs.
One of the 4 corners of the tetrahedron is a detachable operculum which
is bonded to the rest of the egg-shell by cement.
Most of this cement layer, beginning at the inner surface of the shell
and running through almost to the outer surface (a
distance of about 2 μm), is more or less uniform in thickness (30–38
nm), or tapers slightly. About 345 nm from the outer
surface the cement layer narrows abruptly to about 10 nm. The cement is
exposed on the inner surface of the shell, but
in most eggs a layer of shell about 10 nm thick covers the narrow outer
region of the cement layer. When experimentally
perforated eggs were incubated with trypsin, the wide inner layer of cement
was digested, but the narrow outer region
initially remained intact. These observations are discussed in relation
to the following (1) survival of the eggs during
embryonic development, (2) hatching, (3) the ‘hinge’ often
connecting the operculum to the empty egg-shell, (4) the
rapid hatching that occurs in some other monogeneans.
Considerable diversity has been found in the reproductive behaviour of benedeniine (capsalid) monogenean parasites. Mating has been observed in Benedenia sp. 1 from the gills of Lutjanus carponatatus; externally attached spermatophores are not involved and parasites indulge in mutual cross-insemination with intromission. In contrast, there is evidence of spermatophore involvement in Benedenia sp. 2 from the fins of Lethrinus miniatus; mating was not observed but an individual was found carrying an external ovoid spermatophore attached by a stalk lodged in the vagina. In specimens of Benedeniella macrocolpa and B. posterocolpa, in which the male reproductive system was functional and the female system not fully developed, the everted cirrus was seen to be lodged in the parasite's own uterus, with, in some individuals, the tip of the cirrus inside the ootype. This is the first time that the copulatory organ has been observed inside the female reproductive tract of the same individual, not just in benedeniines but in monogeneans in general, and is also the first demonstration that monogeneans are capable of self-insemination via the uterine route.
The eggs and oncomiracidia of two species of the capsalid genus Encotyllabe are described. These parasites were identified tentatively as E. caballeroi Velasquez, 1977 and E. caranxi Lebedev, 1967. If these identifications are correct, then E. caballeroi is recorded from two new hosts, Gymnocranius audleyi and the nemipterid Scolopsis monogramma, and E. caranxi from a new host, Pseudocaranx dentex, and a new locality, Heron Island, Queensland, Australia. Encotyllabines have not previously been recorded from fishes of the family Nemipteridae. The eggs of the two parasites failed to hatch spontaneously and did not hatch when exposed to a variety of potential hatching stimuli, but the oncomiracidia within survived for many weeks. Oncomiracidia expelled from eggs by cover-slip pressure are unciliated and possess a saucer-shaped haptor like that of other capsalids with three pairs of median sclerites and 14 marginal hooklets. The paths of tendons associated with the accessory sclerites and the presence of haptoral loculi suggest that encotyllabines are related to the trochopodines. Observations on a single juvenile specimen of E. caballeroi show that the accessory sclerites and the tendons are lost early in development and that one pair of hamuli (probably the posterior pair) ceases to grow early in post-oncomiracidial life. The loculi persist a little longer but also disappear before full sexual maturity is reached.
A description is given of three contrasting adhesive attitudes exhibited by three species of capsalid monogeneans from the gills of three different species of teleost fish from Heron Island, Queensland, Australia. The proximal end of the primary lamella of the coral trout, Plectropomus maculatus has a wide inner border, free from secondary lamellae, on each flat face. The haptor of Trochopus plectropomi is small enough to attach to this flat surface without folding. Benedenia sp. 1 attaches itself to the gills of stripey, Lutjanus carponatatus, by folding the haptor longitudinally around the inner edge of the primary lamella. Most specimens of T. plectropomi and all specimens of Benedenia sp. 1 were orientated with the anterior end projecting towards the tip of the primary lamella. Benedenia sp. 2 generally prefers relatively flat surfaces in the gill chamber but is more versatile in its choice of attachment sites on its host, the blacktip cod, Epinephelus fasciatus; two specimens were attached to the gill arch, one to a gill raker and one to the dorsal pharyngeal tooth pad.
Using soles (Solea solea) infected experimentally with oncomiracidia of the monogenean skin parasite Entobdella soleae, it was found that the parasite begins to assemble eggs at about 85 days post infection and may survive for as long as 6½12 months at 12± 1°C. Growth of the anterior hamuli continues throughout life but the growth rate decreases with time. The oldest (largest) parasites recovered from laboratory soles were similar in size to the largest parasites collected in the wild.
Mycteronastes undulatae gen. nov., sp. nov. (Monogenea: Monocotylidae) is described from the nasal cavities of Raja undulata caught off Arcachon in France and off Lisbon (Tagus estuary) and Sines in Portugal. Merizocotyle icopae Beverley-Burton & Williams, 1989, be-comes Mycteronastes icopae n. comb., the type species of Mycteronastes gen. nov. Similarities between M. icopae and M. undulatae include the arrangement of the haptor loculi and hooks, the general disposition of the reproductive system, the presence of eyespots and the habitat (the nasal cavities of the host). However, a distinctive feature is the absence of a copulatory sclerite and bulb in M. undulatae. The diagnoses of the following taxa are amended: Monocotylidae, Merizocotylinae and Merizocotyle.
The anatomy and behaviour of the oncomiracidia of Kuhnia scombri, K. sprostonae and Grubea cochlear, related mazocraeid monogeneans from the gill chamber of the mackerel, Scomber scombrus, caught off Plymouth are compared. K. sprostonae and G. cochlear are new records at Plymouth. The most important anatomical difference between these larvae is that those of Kuhnia spp. possess a pair of pigment-shielded eyes which are lacking in G. cochlear. The freshly hatched larvae of Kuhnia spp. are strongly photopositive but this response wanes after about 1 h in K. scombri and 1–5 h in K. sprostonae. No response to light was detected in larvae of G. cochlear. Most older larvae of Kuhnia spp. and of G. cochlear swim continuously upwards and downwards, even in ‘darkness’, indicating an alternation between positive and negative geotropism. The larvae of Kuhnia spp. possess angular cells (?) of unknown function close to the pharynx. The larvae of all three species contain prominent anterior glands and lipid droplets; the latter are depleted during their long free-swimming lives (up to 36 h in Kuhnia spp. at 13–14°C).
An echinostome cercaria (? Cercaria spinifera La Valette, 1855) with 37 collar spines and paraoesophageal glands has been recorded for the first time in Britain from the gastropod Planorbarius corneus. The cercariae penetrate into and encyst in planarians. Observations made on cercariae during penetration indicate that the paraoesophageal glands are used to enter the body of the planarian and that the so-called penetration glands have some other function. Gastropod molluscs may also serve as second intermediate hosts, but there is evidence to indicate that anatomically similar cercariae from different host individuals vary in their second intermediate host preferences.
The eggs of the polyopisthocotylean monogenean Plectanocotyle gurnardi (van Beneden & Hesse, 1863) Llewellyn, 1941, from the gills of gurnards (Triglidae) develop and hatch readily when maintained in the laboratory. However, the impression was gained that some or all of this hatching might be the consequence of inadvertent shadowing or accidental mechanical disturbance of the eggs by the investigators. Since similar stimuli are known to induce hatching in some other monogeneans (see Kearn, 1982; Whittington & Kearn, 1988) and since such stimuli are likely to be generated by the activities of potential hosts, it was decided to embark on a more detailed investigation of hatching in P. gurnardi and to attempt to learn more about the behaviour of gurnards. During these investigations, the availability of freshly hatched larvae of P. gurnardi presented an opportunity to study their behaviour and to expand our knowledge of their anatomy.
Samples of middle ear effusions from 102 children with serous and mucoid otitis media were cultured for mycoplasmas and bacteria. No sample yielded mycoplasmas but bacteria were cultured from 48 (47 per cent). Organisms commonly regarded as pathogens were present in 25 samples (Haemophilus influenzae 17, Streptococcus pneumoniae four, other streptococci four). The only sample from which anaerobic bacteria were isolated was from a patient with cholesteatoma.
It has been established that the wall of the metacercarial cyst of the strigeid digenean Apatemon (Australapatemon) minor from the leech Erpobdella octoculata shares with Apatemon (Apatemon) gracilis the remarkable ability to expel the metacercaria forcibly from the cyst, an event which presumably occurs when the cysts are eaten by the bird definitive host. When cysts of A. minor are treated in vitro with a solution containing a mixture of bile salts and trypsin following pretreatment with acid pepsin, the metacercaria is expelled in an explosive manner through a canal at the narrow end of the pear-shaped cyst. This expulsion is produced by a sudden and substantial inward expansion of the birefringent wall, as a consequence of which the cyst lumen is virtually eliminated. Expulsion of the metacercaria in this explosive manner also occurs when similarly pretreated cysts are exposed to either bile salts alone or to trypsin, but cysts treated with the latter take longer to respond. When the cyst wall is perforated with a needle, inward expansion of the wall occurs and the metacercaria is forcibly ejected through the perforation. A variety of other pretreatments and treatments was tested but pepsin appears to be the most effective “primer”, apparently producing localized changes which permit the exit of the metacercaria. These observations are discussed in relation to the mechanism of expulsion.