bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of josamycine on the control of ileitis in weaned piglets under field conditions
Authors: Kyriakis S. C. , Alexopoulos C. , Saoulidis K. , Lekkas S. , Miliotis CH. C. , Sauveroche B.
Published: March 2003

The effect of josamycine on the control of ileitis in weaned piglets under field conditions.J. vet Pharmacol. Therap.25,279–284.

The aim of this trial was to evaluate the effect of in‐feed josamycine on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at weaning age (25 ± 2 days old) were allocated into three experimental groups, each group comprising of four pens with 24 piglets in each pen. Group one (T1) served the trial as negative control group (unmedicated), group T2 was administered josamycine at 36 mg/kg of feed and group T3 was administered josamycine at 50 mg/kg of feed. Treatments lasted for 14 days followed by an observation period of 28 days. Administration of josamycine at both inclusion levels tested had a beneficial effect compared with the negative control group, by the reduction of prevalence of diarrhoea, the enhancement of growth performance and the reduction of prevalence ofLawsonia intracellularisin the intestine, as determined either by the PCR method or by specific histopathological examinations. The beneficial effect of josamycine was more pronounced at the inclusion level of 50 mg/kg of feed.
Disposition of oral clarithromycin in foals
Authors: Jacks S. , Gigue`re S. , Gronwall R. R. , Brown M. P. , Merritt K. A.
Published: March 2003

Clarithromycin offers numerous advantages over erythromycin and thus, is an attractive alternative for the treatment ofRhodococcus equiinfections in foals. The disposition of clarithromycin was investigated in 6 foals after intragastric administration at a dose of 10 mg/kg body weight. Detectable serum concentrations of clarithromycin were found in 3 of 6 foals at 10 minutes and in all foals by 20 minutes post‐administration. Time to peak serum concentration (Tmax) was 1.5 hours and peak serum concentration (Cmax) was 0.92±0.17 μg/ml. Mean serum concentrations decreased to 0.03 μg/ml at 24 h. No adverse reactions were noted during or after IG administration in any of the foals. Based on the pharmacokinetic parameters, the MIC90ofR. equiisolates, and predicted steady state concentrations, an oral dose of 7.5 mg/kg given every 12 hours would appear appropriate for the treatment ofR. equiinfections in foals.
Pharmacokinetics and toxicity of bromide following high‐dose oral potassium bromide administration in healthy Beagles
Authors: March P. A. , Podell M. , Sams R. A.
Published: March 2003

The pharmacokinetics of a multidose regimen of potassium bromide (KBr) administration in normal dogs was examined. KBr was administered at 30 mg/kg p.o. q 12 h for a period of 115 days. Serum, urine, and cerebrospinal fluid (CSF) bromide (BR) concentrations were measured at the onset of dosing, during the accumulation phase, at steady‐state, and after a subsequent dose adjustment. Median elimination half‐life and steady‐state serum concentration were 15.2 days and 245 mg/dL, respectively. Apparent total body clearance was 16.4 mL/day/kg and volume of distribution was 0.40 L/kg. The CSF:serum BR ratio at steady‐state was 0.77. Dogs showed no neurologic deficits during maintenance dosing but significant latency shifts in waves I and V of the brainstem auditory evoked response were evident. Following a subsequent dose adjustment, serum BR concentrations of approximately 400 mg/dL were associated with caudal paresis in two dogs. Estimated half‐life during the accumulation phase was shorter than elimination half‐lives reported in other studies and was likely related to dietary chloride content. The range of steady‐state concentrations achieved suggests individual differences in clearance and bioavailability between dogs. The described protocol reliably produced serum BR concentrations that are required by many epileptic patients for satisfactory seizure control.
Hepatitis C virus infection and related chronic liver disease in a resident elderly population: the Silea study
Authors: Monica F. , Lirussi F. , Nassuato G. , Castelletto M. R. , Mottola A. , Okolicsanyi L.
Published: March 2003

The prevalence of hepatitis C virus (HCV) infection increases with advancing age, but the disease has been poorly studied in the elderly. A population‐based study was therefore carried out to investigate the prevalence of HCV infection and the severity of HCV‐related chronic liver disease in the elderly. One thousand and sixty‐three people (≥60 years of age) were screened for antibodies to HCV (anti‐HCV) and for possible abnormalities of common liver function tests. Positive subjects and sex and age‐matched anti‐HCV‐ negative controls were recalled 12 months later for measurements of liver enzymes, confirmatory testing of anti‐HCV, HCV RNA analysis and HCV genotyping. All subjects answered a specific questionnaire concerning medical history and possible risk factors. Forty‐four subjects were positive for anti‐HCV, the prevalence being 4.1%. Thirty‐five positive subjects and 35 controls were investigated further. Risk factors for acquiring HCV were found to be: blood transfusion, surgical intervention and the use of non‐disposable syringes. Abnormal alanine aminotransferase levels were found in 13 patients (37.1%). HCV RNA genotyping showed type 1b in three (15.8%), type 2a in 13 (68.4%) and not classified in three (15.8%) patients. There was no relationship between abnormalities of serum aminotransferase, the rate of HCV RNA positivity and HCV genotypes. Ultrasound abnormalities were present in 13 (37.1%) patients. In this elderly population the relatively high prevalence of HCV infection was thought to be caused by previous parenteral exposure. The low incidence of liver disease could be related to the prevalence of HCV genotype 2a in the majority of these patients, and hints at the possibility of an HCV carrier state in elderly individuals.
Hepatitis G virus infection in acute fulminant hepatitis: prevalence of HGV infection and sequence analysis of a specific viral strain
Authors: Sheng L. , Soumillion A. , Beckers N. , Wu C.‐G. , Verslype C. , Nevens F. , Pirenne J. , Aerts R. , Kosala H. , Fevery J. , Yap S. H.
Published: March 2003

Hepatitis G virus (HGV) is a recently discovered RNA virus, which belongs to the Flaviviridae family. Although HGV infection is usually not associated with elevated serum transaminases, some recent studies have reported that HGV infection is found in a significant number of patients with fulminant hepatitis and may play a role in its etiopathogenesis. In this study the prevalence of HGV infection was determined in 500 healthy blood donors and in 24 patients admitted to hospital because of acute liver failure caused by fulminant hepatitis. The presence of HGV RNA was tested in sera, obtained at admission and before any transfusion was given, by a sensitive seminested reverse transcriptase–polymerase chain reaction (RT–PCR) assay specific for detection of the non‐structural (NS)5 region. Nine of the 500 blood donors (1.8%) and two of the 24 patients (8.3%) were found to be HGV RNA positive. One patient was co‐infected with HCV and was known to be an intravenous (i.v.) drug user. After intensive supporting treatment, this patient recovered completely. The second patient had no serological markers of known viral hepatitis infection, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV), Epstein–Barr virus (EBV) and herpes simplex virus (HSV). This patient was successfully transplanted. From both patients, from HGV RNA‐positive healthy blood donors and from other patients coinfected with HCV, a part of the HGV NS3 region (nucleotides 4191–4345, EMBL entry U45966) was cloned and sequenced. Sequence comparison revealed that the NS3 region of HGV in patients with fulminant hepatitis contained three nucleotide substitutions as part of the six substitutions described in previous work. These nucleotide substitutions were not found in the tested blood donors or in patients with HCV co‐infection. Our findings therefore support the concept of the association of fulminant hepatitis with infection of a specific HGV strain.
Mechanism of emergence of hepatitis B virus escape variants: approaches to prevention
Authors: Thomas H. C.
Published: March 2003

Hepatitis B virus causes a chronic infection in a large proportion of cases. One possible mechanism whereby hepatitis B avoids the host defences is by mutation of antigenic epitopes. This article reviews current views in the area.
Human recombinant single‐chain antibody fragments, specific for the hypervariable region 1 of hepatitis C virus, from immune phage‐display libraries
Authors: Zhai W. , Davies J. , Shang D. Z. , Chan S. W. , Allain J. ‐P.
Published: March 2003

The hypervariable region 1 (HVR1) of hepatitis C virus (HCV) may contain a potential neutralization site and the generation of human single‐chain antibody fragments (scFv) to HVR1 may therefore provide a useful tool for the study of HCV. In this report, we have isolated and characterized three anti‐HVR1 scFv clones from two patient‐derived phage‐displayed libraries and HCV HVR1 peptides. scFv S52/20 and S53/6 were selected with serologically cross‐reactive HVR1 peptides. scFv p3f10 was obtained by screening the library from patient MH with an autologous HVR1 peptide. Nucleotide sequencing showed that the VH chains and Vκ chains of all three scFv antibodies were derived from VH3 and Vκ1 family germline V‐genes, respectively. The specificity and affinity of the recombinant scFv antibodies were examined by enzyme‐linked immunosorbent assay (ELISA) and an affinity biosensor, using HVR1 peptides. S52/20 scFv binding to S52 HVR1 peptide was blocked by preincubation with soluble peptide S52 and was partially competed by one of three HCV‐infected patient sera. In addition, scFv S52/20 blocked the binding of HCV‐susceptible Molt‐4 cells to immobilized S52 peptide. This study demonstrates that recombinant human scFv antibodies to HCV HVR1 can be produced in vitro and directly confirms that HVR1 of HCV elicits highly specific antibodies. The very high specificity of these antibodies to HVR1 may limit their potential use in passive immunization therapy against HCV, and further engineering of the scFvs needs to be performed to generate broad‐spectrum blocking scFvs.
Interferon treatment with or without oral ganciclovir in HBeAg‐negative chronic hepatitis B: a randomized study
Authors: Hadziyannis  , Alexopoulou  , Papakonstantinou  , Petraki  , Manesis
Published: March 2003

The treatment of HBeAg‐negative chronic hepatitis B with alpha interferon alone is unsatisfactory. We evaluated the efficacy of combined administration of interferon‐a2a (IFN) with oral ganciclovir, a nucleoside analogue. Forty patients with hepatitis B virus (HBV)‐DNA‐positive/HBeAg‐negative chronic hepatitis B, were randomized to receive 4.5 MU IFN thrice weekly, subcutaneously, alone or in combination with 3 g ganciclovir per os daily for 26 weeks and followed for 12 months after treatment. Mean serum HBV‐DNA levels decreased by 4.0 log10 in the combination group (from 5 × 106 to 4.8 × 102 copies/ml) and by 2.2 log10 in the interferon group (from 8 × 106 to 4.8 × 104 copies/ml) by quantitative polymerase chain reaction (PCR). HBV‐DNA became undetectable in 11 of 20 (55%) and in three of 20 (15%) patients in the two groups, respectively (P=0.02). The alanine aminotransferase levels became normal in all patients receiving combination therapy, compared to 75% of those in the interferon group. After cessation of therapy, HBV‐DNA increased or reappeared in all patients with 85% also relapsing biochemically. One year after treatment, three patients in each group (15%) remained in sustained biochemical remission with very low serum HBV‐DNA levels (median 15 700 copies/ml). We conclude that, in HBeAg‐negative chronic hepatitis B, 6‐month combination therapy with oral ganciclovir and IFN is associated with complete biochemical remission in all treated patients and a 4 log10 decrease in serum HBV‐DNA levels. The end of treatment efficacy of this combination scheme is far super‐ ior to that of IFN monotherapy but sustained responses are few. Further studies are warranted to evaluate the efficacy of prolonged combination schemes with nucleoside analogues and IFN, compared to IFN monotherapy.
Natural course of progression of liver fibrosis in Japanese patients with chronic liver disease type C – a study of 527 patients at one establishment
Authors: Matsumura  , Moriyama  , Goto  , Tanaka  , Okubo  , Arakawa
Published: March 2003

Patients with chronic hepatitis C infection show a gradual progression of fibrosis to liver cirrhosis and hepatocellular carcinoma (HCC). We studied whether the progression of liver fibrosis differed among Japanese subjects who were infected with different hepatitis C virus (HCV) genotypes. In 527 patients we examined whether there was a relationship between gender, age, history of blood transfusion, interval between date of blood transfusion and date of liver biopsy or date of diagnosis of HCC, serum alanine aminotransferase level, platelet count or HCV genotype, with the extent of liver fibrosis, classified into four stages (F1–F4). Moreover, we compared the mean rate of liver fibrosis progression per year in patients with each HCV genotype. Patients who had a higher fibrosis score tended to be older, have a lower platelet count and a longer interval since blood transfusion than those who had a lower fibrosis score. The mean rate of liver fibrosis progression was 0.12 ± 0.15 stages per year after the blood transfusion. However, the progression rate of liver fibrosis in patients who had received a blood transfusion when they were ≥ 30 years of age was 0.19 ± 0.22, while the progression rate of liver fibrosis in the patients who had received a blood transfusion when they were < 30 years was 0.09 ± 0.09. In conclusion, chronic hepatitis C is a progressive disease, and patients with genotype 1b, 2a and 2b have a similar rate of progression of liver fibrosis. Particular attention should be paid to patients who are infected with HCV when ≥ 30 years of age, because intrahepatic fibrosis rapidly progresses in these patients.
Retreatment for 24 vs 48 weeks with interferon‐α2b plus ribavirin of chronic hepatitis C patients who relapsed or did not respond to interferon alone
Authors: Enríquez J. , Gallego A. , Torras X. , Pérez‐Olmeda T. , Diago M. , Soriano V. , Luján M.‐S. , García‐Samaniego J.
Published: March 2003

We assessed the efficacy of interferon (IFN) plus ribavirin over 24 or 48 weeks for the retreatment of patients with chronic hepatitis C who had relapsed or did not respond to a previous course of IFN. One‐hundred and twenty patients (69 non‐responders and 51 relapsers) were randomly assigned to receive IFN‐α2b (3 million units thrice weekly) plus ribavirin (1000–1200 mg per day) for 24 weeks (group A: 58 patients) or 48 weeks (group B: 62 patients). Treatment was discontinued at week 12 if the alanine aminotransferase (ALT) level remained elevated. The rate of sustained response was 15.5% in group A and 37.1% in group B (P=0.013). Relapsers treated for 48 weeks had a sustained response rate of 66.6% compared with a sustained response rate of only 25% in those treated for 24 weeks (P=0.004). Moreover, a sustained response was seen in 14.3% of non‐responders treated for 48 weeks and in 8.8% of those treated for 24 weeks (P=0.71). Fifty‐three per cent of patients with a normal ALT level and undetectable hepatitis C virus (HCV) RNA at week 12 had a sustained response compared with 14% of those who were HCV RNA positive at week 12 (P < 0.001). Independent predictive factors of sustained response were: therapy for 48 weeks (P=0.0026), relapse after IFN treatment (P=0.0006), loss of HCV RNA at week 12 (P=0.0008) and HCV genotype non‐1 (P=0.024). Hence, in patients with chronic hepatitis C who failed to respond to a previous course of IFN monotherapy, combination therapy with IFN plus ribavirin for 48 weeks seems to be more effective than IFN plus ribavirin for 24 weeks.
Changing scenario of hepatitis A virus and hepatitis E virus exposure among the primitive tribes of Andaman and Nicobar Islands, India over the 10‐year period 1989–99
Authors: Murhekar M. V. , Sehgal S. C. , Murhekar K. M. , Padbhidri S. P. , Chitambar S. D. , Arankalle V. A.
Published: March 2003

The Andaman and Nicobar Islands, Union Territory of India, are home to six primitive tribes. Studies carried out earlier among these tribes revealed very high rates of hepatitis B infection. We have now studied hepatitis A and E infection among them. A total of 951 serum samples were collected from four accessible tribes (Nicobarese, Shompens, Onges and Great Andamanese) and tested for antibodies against hepatitis A and E viruses. In addition, 240 serum samples collected a decade earlier from age‐stratified Nicobarese were also screened. Hepatitis A virus (HAV) infection was found to be highly endemic among all the tribes, whereas hepatitis E virus (HEV) infection was common among the Nicobarese and Shompens. The age group‐wise prevalence of these infections among the Nicobarese showed different patterns, HAV prevalence rising significantly from those aged 10 years and thereafter reaching a plateau, whereas HEV prevalence was found to be more evenly distributed over all age groups, but rising somewhat after 30 years of age. Over the last decade, the prevalence of HAV among the Nicobarese has declined slightly, particularly in those aged 10 years or less whereas HEV infection has more than doubled over all age ranges. Different HEV prevalence observed among the tribes could not be attributed to differences in sanitation or water supply. This fact and the different age‐wise patterns of HAV and HEV prevalences is suggestive of different modes of transmission of HEV that are not shared. The highest rates for HEV were among those tribes which reared pigs suggesting that pigs might serve as reservoir of HEV. Further studies are needed, however, to validate these findings.
The application of GIS‐modelling to mustelid landscape ecology
Authors: Gough Mary C. , Rushton Stephen P.
Published: March 2003

Landscapes are mosaics of habitat patches. The composition, configuration and connectivity of these elements changes in space and time as a result of ‘natural’ and human disturbance. Landscapes provide the ecological template for the life history and behavioural processes that determine animal spacing patterns. An understanding of the effects of landscape dynamics on mammal distributions is therefore vital if populations are to be managed effectively. Members of the Mustelidae present a considerable practical and theoretical challenge because of the great range of morphological, behavioural and ecological variation within the family. Habitat use data have been gathered only for a small number of Mustelidae species and most studies have been conducted with few individuals at small spatial scales and over relatively short time spans. Consequently, our knowledge of the landscape ecology of mustelids is very limited. Modelling can provide a strong conceptual framework for investigating mustelid‐habitat relationships. We review the potential of different modelling approaches for analysing the influence of landscape dynamics on the distributions of mustelids.
Sugar meals and longevity of the sandfly Phlebotomus papatasi in an arid focus of Leishmania major in the Jordan Valley
Authors: Schlein Yosef , Jacobson Raymond L.
Published: March 2003

The sugar diet and life‐span of Phlebotomus papatasi were studied in a typical zoonotic focus of Leishmania major in an arid area of the Jordan Valley during 1996–1997. Plant‐tissue residues (cellulose particles) were identified in the stained guts of 23% of P. papatasi and significant amounts of sugar were found in the gut of 16%. Feeding on different plants was demonstrated by using their branches, suffused with cellulose stain, as baits in the field. Ingested, stained cellulose was detected in 10% of the sandflies (6% of males, 12.5% of females) caught near bait‐branches of common local plants, mostly Chenopodiaceae. The similar rates of plant and sugar feeding, with the observed absence of aphids (ruling out the availability of honeydew), implied that the sugar meals of sandflies were obtained directly from plants.

The relative paucity of sugar meals in P. papatasi coincided with a short life‐span, evaluated by daily growth lines in the cuticle. The age of the oldest females was estimated to be 8 days, and 6 days for males. Under local conditions, the first gonotrophic cycle can be completed in 6 days and the usual transmission of L. major is apparently afterwards, when females ingest blood to initiate another cycle. Only about 9% of P. papatasi females survived > 6 days.
Molecular and kinetic evidence for allelic variants of esterase Estβ1 in the mosquito Culex quinquefasciatus
Authors: Small G. J. , Karunaratne S. H. P. P. , Chadee D. D. , Hemingway J.
Published: March 2003

Elevated esterase Estβ1 was purified from larvae of newly isolated strains of the mosquito Culex quinquefasciatus from Colombia (COL) and Trinidad (TRI) with resistance to organophosphate (OP) insecticides. Insecticide interactions were compared with those of elevated Estβ12 from the OP‐resistant Habana strain and the non‐elevated Estβ13 from the susceptible PelSS strain. On the basis of insecticide binding efficiency, all elevated Estβ1 esterases were readily distinguishable. Differences between the EcoRI restriction fragment patterns of the amplified estβ1 gene in COL and TRI strains compared with each other, and between amplified estβ11, estβ12 and the non‐amplified estβ13, suggest differences in their nucleotide sequence. Considering their variable insecticide binding efficiencies, these genetic differences would imply that, in contrast to estα2 and estβ2, amplification of estβ1 has occurred several times independently. Generally, the elevated Estβ1s were more reactive with insecticides than the non‐elevated Estβ13. This supports the hypothesis that the elevated esterase‐based mechanism confers resistance through amplification of alleles coding for esterases which have a greater specificity for the insecticides they sequester than the esterases coded by their non‐amplified counterparts.
Experimental comparison of anthropophily between geographically dispersed populations ofLutzomyia whitmani(Diptera: Psychodidae)
Authors: Campbell‐Lendrum D. H. , Pinto M. C. , Brandão‐Filho S. P. , De Souza A. A. , Ready P. D. , Davies C. R.
Published: March 2003

Lutzomyia whitmani, a major vector of cutaneous leishmaniasis in Brazil, occupies diverse habitats from the Amazon forest canopy to suburban animal pens. Three mitochondrial lineages ofLu. whitmani(‘Amazonian’, ‘North–South’ and ‘North‐east’) have parapatric distributions coinciding with different ecological zones. We assessed the host preferences of populations representing the three lineages in standardized field experiments, and found thatLu. whitmaniin all sites were significantly more attracted to humans than to dogs or chickens. Females from a southerly population of the North–South lineage showed the greatest degree of anthropophily.Lu. whitmanifrom Amazonia were also strongly attracted to human baits, contradicting previously published accounts. Intraspecific comparisons in non‐Amazonian sites suggest thatLu. whitmaniis less anthropophilic thanLu. intermediabut more so thanLu. longipalpis. No significant difference was detected in anthropophily betweenLu. whitmaniin the Amazon and eitherLu. dendrophylaorLu. gomezi. Anthropophilic behaviour was demonstrated in the same site forLu. complexa,Lu. flaviscutellataandLu. brachyphalla, but not forLu. infraspinosa.
Laboratory testing of a lethal ovitrap for Aedes aegypti
Authors: Zeichner B. C. , Perich M. J.
Published: March 2003

Laboratory tests were conducted to determine the feasibility of making the mosquito ovitrap lethal to Aedes aegypti (L.) when they attempt to oviposit in the trap. Heavy‐weight velour paper strips (2.54 × 11 cm) were used as an alternative to the wooden paddle normally provided as a substrate for mosquito oviposition. The paper strips were pretreated with insecticide solutions and allowed to dry before being used in oviposition cups of 473 ml capacity, filled with water initially to within 2.5 cm of the brim. Insecticides chosen for their quick knock‐down efficacy were bendiocarb 76% WP (1.06 mg a.i./strip) and four pyrethroids: permethrin 25% WP (0.16 mg a.i./strip), deltamethin 4.75% SC (0.87 mg a.i./strip), cypermethrin 40% WP (2.81 mg a.i./strip), and cyfluthrin 20% WP (0.57 mg a.i./strip).

 For experimental evaluation, two oviposition cups (one with an insecticide‐treated strip and one with an untreated strip) were placed in cages (cubic 30 cm) with gravid female Ae. aegypti mosquitoes (aged 6–8 days) from a susceptible laboratory strain. Mortality‐rates of female mosquitoes were 45% for bendiocarb, 47% for permethrin, 98% for deltamethrin, 100% for cypermethrin, and 100% for cyfluthrin. Young instar larvae added to the treated cups died within 2 h. After water evaporation from the cups for 38 days, fresh mosquito females had access to previously submerged portions of the velour paper paddle, and mortality rates of 59% or more occurred. Cups that had water (360 ml) dripped into them, to simulate rain, produced female mosquito mortality rates of > 50% and all larvae died within 3 h of being added. These tests demonstrate that the ovitrap can be made lethal to both adults and larvae by insecticidal treatment of the ovistrip. Field efficacy trials are underway in Brazil to access the impact of this simple, low‐cost, environmentally benign approach on populations of the dengue vector Ae. aegypti.
Identification of bloodmeals in haematophagous Diptera by cytochrome B heteroduplex analysis
Authors: Boakye D. A. , Tang J. , Truc P. , Merriweather A. , Unnasch T. R.
Published: March 2003

We developed a DNA assay for bloodmeal identification in haematophagous insects. Specific host cytochrome B gene sequences were amplified by PCR and classified on the basis of their mobility in a heteroduplex assay. In the blackfly Simulium damnosum s.l. (Diptera: Simuliidae), human cytochrome B DNA sequences were identifiable up to 3 days following ingestion of the bloodmeal. In the tsetse Glossina palpalis (Diptera: Glossinidae) collected from tsetse traps in Ivory Coast, bloodmeals were identified as taken from domestic pigs on the basis of their heteroduplex pattern and DNA sequence. Evidently the cytochrome B sequence shows sufficient interspecific variation to distinguish between mammalian host samples, while exhibiting minimal intraspecific variation. The stability of DNA in bloodmeals, for several days post‐ingestion by haematophagous insects, allows PCR‐HDA assays to be used reliably for host identification.
Susceptibility of British head lice, Pediculus capitis, to imidacloprid and fipronil
Authors: Downs A. M. R. , Stafford K. A. , Coles G. C.
Published: March 2003

The head louse, Pediculus capitis De Geer (Phthiraptera: Pediculidae) has developed resistance to organochlorines, the organophosphate malathion and to pyrethroids in the U.K. Therefore, headlice from Bristol school children were bioassayed against two new insecticides, fipronil and imidacloprid. Pediculus capitis was fully susceptible to imidacloprid, but it required a relatively high dose and acted slowly. Fipronil acted faster at lower dose, but seemed to be affected by cross‐resistance in a small proportion of P. capitis.
Permethrin resistance ratios compared by two methods of testing nymphs of the German cockroach, Blattella germanica
Authors: Ladonni H.
Published: March 2003

For the German cockroach, Blattella germanica L. (Dictyoptera: Blattellidae), the permethrin resistance ratio (RR) was assessed by topical application and by tarsal contact tests, using first‐instar nymphs of five strains from Tehran, Iran. Each test was replicated three or four times with 10 nymphs aged 2–3 days; mortality was scored 24 h post‐treatment. The reference susceptible strain showed LD50 permethrin 0.0175 μl/nymph from topical application, KT50 of 8.41 min and LT50 of 12.82 following tarsal contact with permethrin 15 mg/m2. In four wild strains (F1 generation) the RR varied from 4.14 to 4.7 for mortality after topical application, from 4.2 to 6.45 for mortality and 17–27 for knockdown following tarsal contact tests. Hence, overall knockdown results gave much higher RRs than for mortality data. Resistance ratios based on both methods of treatment were very similar: one strain showed a slightly higher value by topical application (RR 4.6 vs. 4.2, i.e. 1.1‐fold difference) whereas the other three strains gave slightly greater RR (1.2–1.4 fold) by tarsal contact. Resistance was abolished by cotreatment with the synergist piperonyl butoxide plus permethrin (ratio 3 : 1 required for full efficacy), indicating that mixed‐function oxidases were inhibited as a major metabolic pathway in all four resistant strains.
Cost‐comparison of DDT and alternative insecticides for malaria control
Authors: Walker K.
Published: March 2003

In anti‐malaria operations the use of DDT for indoor residual spraying has declined substantially over the past 30 years, but this insecticide is still considered valuable for malaria control, mainly because of its low cost relative to alternative insecticides. Despite the development of resistance to DDT in some populations of malaria vector Anopheles mosquitoes (Diptera: Culicidae), DDT remains generally effective when used for house‐spraying against most species of Anopheles, due to excitorepellency as well as insecticidal effects. A 1990 cost comparison by the World Health Organization (WHO) found DDT to be considerably less expensive than other insecticides, which cost 2 to 23 times more on the basis of cost per house per 6 months of control. To determine whether such a cost advantage still prevails for DDT, this paper compares recent price quotes from manufacturers and WHO suppliers for DDT and appropriate formulations of nine other insecticides (two carbamates, two organophosphates and five pyrethroids) commonly used for residual house‐spraying in malaria control programmes. Based on these ‘global’ price quotes, detailed calculations show that DDT is still the least expensive insecticide on a cost per house basis, although the price appears to be rising as DDT production declines. At the same time, the prices of pyrethroids are declining, making some only slightly more expensive than DDT at low application dosages. Other costs, including operations (labour), transportation and human safety may also increase the price advantages of DDT and some pyrethroids vs. organophosphates and carbamates, although possible environmental impacts from DDT remain a concern. However, a global cost comparison may not realistically reflect local costs or effective application dosages at the country level. Recent data on insecticide prices paid by the health ministries of individual countries showed that prices of particular insecticides can vary substantially in the open market. Therefore, the most cost‐effective insecticide in any given country or region must be determined on a case‐by‐case basis. Regional coordination of procurement of public health insecticides could improve access to affordable products.
Impact of irrigation on malaria in Africa: paddies paradox
Authors: Ijumba J. N. , Lindsay S. W.
Published: March 2003

The high population growth rate of the African continent has led to an increased demand for food and is in danger of outstripping agricultural production. In order to meet this need, many governments have sought ways of improving food production by initiating large‐scale irrigation projects, involving reclamation of arid and semi‐arid areas for the cultivation of crops. Although crop irrigation promises one solution to alleviating hunger and encourages economic growth, irrigation has often been blamed for aggravating disease in local communities. Malaria is one of the major tropical diseases associated with irrigation schemes, and changes in the transmission pattern of this disease following irrigation development have been a perennial subject of debate. It has often been assumed that high numbers of malaria vector Anopheles mosquitoes (Diptera: Culicidae) resulting from irrigation schemes lead inevitably to increased malaria in local communities. However, recent studies in Africa have revealed a more complex picture. Increased numbers of vectors following irrigation can lead to increased malaria in areas of unstable transmission, where people have little or no immunity to malaria parasites, such as the African highlands and desert fringes. But for most of sub‐Saharan Africa, where malaria is stable, the introduction of crop irrigation has little impact on malaria transmission. Indeed, there is growing evidence that for many sites there is less malaria in irrigated communities than surrounding areas. The explanation for this finding is still unresolved but, in some cases at least, can be attributed to displacement of the most endophilic and anthropophilic malaria vector Anopheles funestus Giles by An. arabiensis Patton with lower vectorial capacity, as the latter thrives more than the former in ricefields. Similarly, among members of the An. gambiae complex, some cytotypes of An. gambiae sensu stricto are more vectorial than others. For example, the Mopti form has high vectorial capacity and breeds perennially in irrigated sites, whereas the savanna form is often sympatric but more seasonal. Also we suggest that many communities near irrigation schemes benefit from the greater wealth created by these schemes. Consequently irrigation communities often have greater use of bednets, better access to improved healthcare and receive fewer infective bites compared with those outside such development schemes. Thus, in most cases, irrigation schemes in Africa do not appear to increase malaria risk, except in areas of unstable transmission. However, developers should take the opportunity to improve health‐care facilities for local communities when planning irrigation schemes wherever they occur.
Validity of species status of the parasitic mite  Otodectes cynotis
Authors: Lohse J. , Rinder H. , Gothe R. , Zahler M.
Published: March 2003

Abstract A combined molecular and phenotypic approach was used to determine whether ear mites of the genus Otodectes (Acari: Psoroptidae) belong to a single species. The second internal transcribed spacer (ITS 2) of the rDNA of 16 isolates from 11 cats, two dogs, one arctic fox and two ferrets originating from four different continents was characterized. In addition, mites from dog, cat and arctic fox were investigated morphologically. Sequence comparisons revealed five different, but closely related genotypes which did not segregate according to host species or geographical origin. Morphologically, mites of the three host species did not differ significantly in their body or leg sizes. These investigations support the view that ear mites of the genus Otodectes from different hosts and geographical origins belong to a single species, Otodectes cynotis (Hering).
Simultaneous identification of species and molecular forms of the Anopheles gambiae complex by PCR‐RFLP
Authors: Fanello C. , Santolamazza F. , Della Torre A.
Published: March 2003

Abstract For differential identification of sibling species in the Anopheles gambiae Giles complex (Diptera: Culicidae), including simultaneous separation of M and S molecular forms within An. gambiae Giles sensu stricto, we describe a PCR‐RFLP method. This procedure is more efficient, faster and cheaper than those used before, so is recommended for large‐scale processing of field‐collected larval and adult specimens to be identified in malaria vector studies.
Are vocationally trained general practitioners better GPs? A review of research designs and outcomes
Authors: Hindmarsh J Harré , Coster G D , Gilbert C
Published: March 2003

Implicit and explicit in reviews of and changes to vocational education for general practitioners in the 1990s is the challenge to defend the assumption that vocationally trained GPs are better GPs. This paper provides a review of the international literature which has reported on outcomes of general practice vocational training programmes. Through the review we identify both the types of research methodologies used (including a brief discussion of their strengths and limitations) and the outcomes reported of vocational training. Twenty‐five studies on the outcomes of vocational training are reviewed. These studies used multiple data sources and one of four methodologies: pre‐ and post‐training comparisons, analysis of learners' or teachers' accounts, audits of general practice or analysis of examination pass rates. When collated, the following range of outcomes from vocational training were identified: improved quality of patient care, increased knowledge, improved general practice skills, increased confidence and desirable GP attitudes and personality traits, increased adherence to practice guidelines and higher examination pass rates. The paper concludes with a summary of research and education issues which arise when we examine the question posed at the outset: are trained GPs better GPs?
An international database on medical education: the European Medical School Information System (EMSIS)
Authors: Eysenbach G , Cloos J‐M , Jacobsen C T , Antepohl W
Published: March 2003

An electronic database containing the curricula and other information of more than 200 medical schools from 40 different countries has been compiled and made accessible via the World Wide Web (http://yi.com/emsis), with the aims of providing an overview and to enable a comparison of the curricula of Medical Schools in Europe, of facilitating the cooperation between Medical Schools in Europe and allowing medical students to plan their studying period abroad. The database contains the addresses of medical schools, general information about each medical school (number of students, hospital beds available for teaching, etc.), exchange information (exchange networks the medical school is participating in) and extensive curriculum information, consisting of more than 10 000 course descriptions. All information has largely been entered by the medical schools themselves. Medical schools may update the database directly via the Internet at any time. Users may perform simple queries, for example by country or city, or may perform more complex searches such as `show all medical schools teaching gynaecology in the fourth year'.
Supporting the bereaved relative: reflections on the actor's experience
Authors: Sutton
Published: March 2003

For several months I and a team of fellow performers were involved, as simulated bereaved relatives, with a research project based in hospitals in the north‐west of England. The project, the European Donor Hospital Education Programme, EDHEP (UK), was set up in order to provide a research input into the already established EDHEP in Europe. The programme is designed to develop communication and interpersonal skills among health care workers in Intensive Care/Therapy Units, especially in the breaking of bad news of death to near relatives and in asking consent for the removal of tissues and/or organs for transplantation. The associated research was initiated by an international grouping of clinical psychologists with the purpose of assessing the efficacy of the training schedule. Results are expected soon from the main body of research, some aspects of which provide analytical data drawn from encounters between health care professionals and actors as simulated relatives. Here, however, the experiences and feelings of the `relatives' themselves are described, discussed and reflected upon.
Computer‐aided learning: an overvalued educational resource?
Authors: Devitt Peter , Palmer Edward
Published: March 2003

Aim

 The aim of this study was to evaluate the place of computer‐aided learning in a basic science course in the undergraduate medical curriculum at the University of Adelaide.

Methods

 A software program was written which would allow students to study the anatomy and physiology of the liver and biliary tree in three different styles. Identical content was produced, matched for each style (problem‐based, didactic and free text response) and students randomly allocated to one of four groups (three computer and one control). Students were tested before and after access to the program.

Results

 Ninety second‐year students completed the study. Those students who had access to the material in the problem‐based and free text response styles did no better in the post‐study test than the controls, whilst the group who had studied the didactically presented computer material performed significantly better than the other three groups. All three computer groups accessed the material on a similar number of occasions, but the group who had access to the free text entry program spent significantly less time on computer study.

Conclusions

 If computer materials are to be provided as a learning resource for the basic medical sciences, provision must be made for the style of teaching of the course and the style of learning of the students attending that course.
Invasion genetics of the Mediterranean fruit fly: variation in multiple nuclear introns
Authors: VILLABLANCA F. X. , RODERICK G. K. , PALUMBI S. R.
Published: March 2003

Biological invasions generally start from low initial population sizes, leading to reduced genetic variation in nuclear and especially mitochondrial DNA. Consequently, genetic approaches for the study of invasion history and population structure are difficult. An extreme example is the Mediterranean fruit fly,Ceratitis capitata(Medfly), for which successive invasions during this century have resulted in a loss of 60% of ancestral genetic variation in isozymes and 75% of variation in mitochondrial DNA. Using Medflies as an example, we present a new approach to invasion genetics that measures DNA sequence variation within introns from multiple nuclear loci. These loci are so variable that even relatively recently founded Medfly populations within California and Hawaii retain ample genetic diversity. Invading populations have only lost 35% of the ancestral genetic variation. Intron variation will allow high‐resolution genetic characterization of invading populations in both natural and managed systems, although non‐equilibrium methods of analysis may be necessary if the genetic diversity represents sorting ancestral polymorphism.
Habitat islands, genetic diversity, and gene flow in a Patagonian rodent
Authors: KIM I. , PHILLIPS C. J. , MONJEAU J. A. , BIRNEY E. C. , NOACK K. , PUMO D. E. , SIKES R. S. , DOLE J. A.
Published: March 2003

The effects of terrestrial habitat islands on gene flow and genetic diversity in animal populations have been predicted and discussed in theoretical terms, but empirical data are needed to test these predictions and provide an understanding of the relationships of life‐history characteristics to genetics of insular species. We studied saxicolous mice (Phyllotis xanthopygus) in Patagonia to explore genetic structure, phylogeography, and gene flow in a species inhabiting natural habitat islands. Phylogeographic analyses based on mtDNA sequences revealed two haplotype clades, which presumably reflect early Pleistocene factors that temporarily separated the mice into two geographically isolated groups. The Río Chubut, which lies within a glacial drainage basin bisecting northern Patagonia, might have affected gene flow in the species. Although we anticipated isolation by distance and founder phenomena associated with habitat islands, in some habitat patches we found evidence of high local genetic diversity. The amount of divergence in the mitochondrial cytochrome b gene (≈ 3.4%) in animals at a single locality could best be explained through a combination of historical factors and metapopulation source–sink theory. Demographic shifts, dispersal, and episodic recolonization are important in the life history and genetic population structure of P. xanthopygus.
The use of (GACA)4 PCR to sex Old World vultures (Aves: Accipitridae)
Authors: WINK M. , SAUER‐GÜRTH H. , MARTINEZ F. , DOVAL G. , BLANCO G. , HATZOFE O.
Published: March 2003

A PCR method was developed employing a single primer (GACA)4 to sex Black vultures (Aegypius monachus), Lappet‐faced vultures (Torgos tracheliotus), and Griffon vultures (Gyps fulvus). Using the (GACA)4 primer several PCR products were generated. One or more PCR products displayed a sex‐specific pattern, i.e. they were only present in females (probably corresponding to repetitive DNA on the W chromosome) but absent in males. The sex ratio of 85 Griffon vultures from Spain was almost 1.
Microsatellite analysis of genetic population structure in an endangered salmonid: the coastal cutthroat trout (Oncorhynchus clarki clarki)
Authors: WENBURG JOHN K. , BENTZEN PAUL , FOOTE CHRIS J.
Published: March 2003

The genetic population structure of coastal cutthroat trout (Oncorhynchus clarki clarki) in Washington state was investigated by analysis of variation in allele frequencies at six highly polymorphic microsatellite loci for 13 anadromous populations, along with one outgroup population from the Yellowstone subspecies (O. clarki bouvieri) (mean heterozygosity = 67%; average number of alleles per locus = 24). Tests for genetic differentiation revealed highly significant differences in genotypic frequencies for pairwise comparisons between all populations within geographical regions and overall population subdivision was substantial (FST = 0.121, RST = 0.093), with 44.6% and 55.4% of the among‐population diversity being attributable to differences between streams (FSR = 0.054) and between regions (FRT = 0.067), respectively. Analysis of genetic distances and geographical distances did not support a simple model of isolation by distance for these populations. With one exception, neighbour‐joining dendrograms from the Cavalli‐Sforza and Edwards’ chord distances and maximum likelihood algorithms clustered populations by physiogeographic region, although overall bootstrap support was relatively low (53%). Our results suggest that coastal cutthroat trout populations are ultimately structured genetically at the level of individual streams. It appears that the dynamic balance between gene flow and genetic drift in the subspecies favours a high degree of genetic differentiation and population subdivision with the simultaneous maintenance of high heterozygosity levels within local populations. Results are discussed in terms of coastal cutthroat trout ecology along with implications for the designation of evolutionarily significant units pursuant to the US Endangered Species Act of 1973 and analogous conservation units.
A DNA test to sex most birds
Authors: GRIFFITHS RICHARD , DOUBLE MIKE C. , ORR KATE , DAWSON ROBERT J. G.
Published: March 2003

Birds are difficult to sex. Nestlings rarely show sex‐linked morphology and we estimate that adult females appear identical to males in over 50% of the world's bird species. This problem can hinder both evolutionary studies and human‐assisted breeding of birds. DNA‐based sex identification provides a solution. We describe a test based on two conserved CHD (chromo‐helicase‐DNA‐binding) genes that are located on the avian sex chromosomes of all birds, with the possible exception of the ratites (ostriches, etc.; Struthioniformes). The CHD‐W gene is located on the W chromosome; therefore it is unique to females. The other gene, CHD‐Z, is found on the Z chromosome and therefore occurs in both sexes (female, ZW; male, ZZ). The test employs PCR with a single set of primers. It amplifies homologous sections of both genes and incorporates introns whose lengths usually differ. When examined on a gel there is a single CHD‐Z band in males but females have a second, distinctive CHD‐W band.