bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative oral bioavailability of microgranulated amoxicillin in pigs
Authors: Anfossi P. , Zaghini A. , Grassigli G. , Menotta S. , Fedrizzi G.
Published: March 2003

A new microgranulated formulation of amoxicillin trihydrate for in‐feed medication was developed using a lipogelled matrix. Its relative bioavailability was compared with powdered drug in pigs and an assessment was made to determine whether therapeutic concentrations were achieved. Microgranules containing 10% (MICR10) and 30% (MICR30) amoxicillin and free amoxicillin trihydrate powder (reference, AMX) were administered at dosages of 50 mg of amoxicillin/kg b.w. using a three‐way‐crossover design. Amoxicillin analysis in serum was performed by a sensitive high performance liquid chromatography (HPLC) method with fluorometric detection, using an extraction procedure already described for edible tissues of fish and adapted and validated for pig serum. The oral bioavailability of both microgranulated formulations was higher than that of the reference formulation [relative bioavailability (F): 153.9 ± 58.2% for MICR10; 126.2 ± 70.5% for MICR30] and the area under the concentration–time curve (AUC) values of MICR10 and AMX formulations were significantly different (P < 0.05). Differences between the mean maximum concentration (Cmax), time of Cmax (tmax) and mean residence time (MRT) of the drug formulations were not significant. Microgranulated amoxicillin is suitable for in‐feed administration to pigs and, because of its higher oral bioavailability compared with the powdered compound, it may be more effective for the treatment of susceptible infections.
Current status of HBV vaccine escape variants – a mathematical model of their epidemiology
Authors: Wilson J. N. , Nokes D. J. , Carman W. F.
Published: March 2003

We present a deterministic model of the possible emergence of a vaccine escape variant of hepatitis B virus (HBV). The model identifies the key unknowns determining this process: the protection afforded by the current vaccines against particular HBV variants; the infectiousness of these variants; and the current prevalence of individuals infectious with the variants (each factor relative to wild‐type). By making pessimistic assumptions about these unknowns we show that even a highly infectious variant, under a vaccine programme that affords no protection against the variant, would still take decades to emerge. Thus the current low prevalence of variants is not evidence for the cross‐reactivity of the current vaccines or for a lack of infectiousness in the variants. As any vaccine failure will be inapparent for decades it may be sensible to recommend vaccine modifications now rather than later.
Pathogenicity of GBV‐C/HGV infection
Authors: Müller C.
Published: March 2003

Extensive studies of GBV‐C/HGV in acute and chronic hepatitis non‐A–non‐E have failed to provide hard evidence for a major role in this disease. Persistent GBV‐C/HGV viraemia is in most cases associated with normal ALT levels, and only in a minority of patients are mild elevations of aminotransferases found. Its disease‐inducing capacity is questionable and the findings accumulated so far are best explained by looking at GBV‐C/HGV as a well‐adapted, predominantly parenterally transmitted, persistent virus; it might be transmitted concomitantly with another, still unidentified hepatitis non‐A–non‐E virus. This does not exclude the possibility that GBV‐C/HGV might, in some rare cases and under certain circumstances, induce a hepatitis‐like illness as seen with other viruses such as EBV or CMV. GBV‐C/HGV definitely plays a minor role only, if any, in post‐transfusion and community‐acquired hepatitis non‐A–non‐E.
Histological and virological long‐term outcome in patients treated with interferon‐α2b and ribavirin for chronic hepatitis C
Authors: Schvarcz R. , Glaumann H. , Reichard O. , Weiland O.
Published: March 2003

Long‐term virological and histological outcome following interferon‐α2b (IFN‐α2b) and ribavirin treatment for 24 weeks was studied in 20 patients with chronic hepatitis C who were without a lasting response to IFN as monotherapy. Following combination therapy, sustained virological response (SR) was achieved in 12 patients (i.e. hepatitis C virus (HCV) RNA negative in serum 6months post‐treatment). Eleven of these patients remained HCV RNA negative in serum 2 years post‐treatment. A virological long‐term response (LTR) was more frequent in patients with a previous end‐of‐treatment response to IFN monotherapy than in non‐responders. Liver histology at follow‐up, ≥24months post‐treatment, showed substantial improvement in patients with a virological LTR to the combination treatment. In all nine patients biopsied at the 2‐year follow‐up, liver inflammation had disappeared totally (grade=0), and the stage (fibrosis) had improved. In contrast, no significant changes in grade or stage were noted in patients with a virological non‐LTR to combination treatment. A significant improvement in inflammation was noted, in patients with a virological LTR, from 3.6 to 0.2 (P<0.01) and in fibrosis from 2.0 to 1.4 (P<0.05) whereas the corresponding scores for patients with a virological non‐LTR did not change significantly, from 3.1 to 1.5 for inflammation and for fibrosis from 1.3 to 1.3. We conclude that patients with chronic hepatitis C who achieve a virological sustained response 6months post‐treatment with IFN‐α2b and ribavirin will remain virological responders for a follow‐up period of least 24months, concomitant with a disappearance of inflammatory activity and a marked improvement of fibrosis in the liver.
Mycophenolic acid, an immunosuppressive agent, inhibits HBV replication in vitro
Authors: Gong Z. J. , De Meyer S. , Clarysse C. , Verslype C. , Neyts J. , De Clercq E. , Yap S. H.
Published: March 2003

Mycophenolate mofetil (MMF), the morpholinoethyl ester of mycophenolic acid (MPA), is currently used as an immunosuppressive agent in kidney transplant recipients. After oral administration, MMF is hydrolysed to MPA, the active compound, which is a potent inhibitor of inosine monophosphate dehydrogenase (IMP‐DH). Inhibition of this enzyme results in a depletion of the intracellular GTP and dGTP pools. MPA has been shown to inhibit the replication of a number of viruses, including arena viruses (Junin and Tacaribe), yellow fever virus, reovirus‐1, parainfluenza‐3 virus, Coxsackie B4 virus, Epstein–Barr virus and human immunodeficiency virus. To examine whether MPA also has an inhibitory effect on HBV replication, experiments were performed using cultures of primary human hepatocytes and HBV‐transfected, HepG2 2.2.15 cells. After in vitro infection with HBV in human hepatocytes, HBV covalently‐closed‐circular (ccc) DNA and HBV mRNAs were detectable in the cells during the 10 days following infection. HBV DNA and hepatitis B surface antigen (HBsAg) were also secreted into the culture medium. In the presence of 10 μg ml–1 MPA (the therapeutic serum level of MPA as an immunosuppressive agent) in culture medium, HBV ccc DNA and HBV mRNAs became undetectable 5 days after treatment was started. The secretion of HBV DNA and HBsAg into the medium was also markedly reduced. No cytotoxic effect of the drug was noted during the experiments. The effect of MPA on HBV replication was abolished by the presence of guanosine (50 μg ml–1). In HepG2 2.2.15 cells (which contain an integrated tandem dimer of the HBV genome), MPA treatment had no significant inhibitory effect on the secretion of HBV DNA and HBsAg into the culture medium. HBV ccc DNA and HBV mRNAs in HepG2 2.2.15 cells were also not affected. The observed effect of MPA on HBV replication in primary human hepatocyte cultures may involve only episomal replication and may have clinical implications, especially before integration of HBV DNA into the host genome.
Statistical models for predicting response to interferon‐α and spontaneous seroconversion in children with chronic hepatitis B
Authors: Comanor  , Minor  , Conjeevaram  , Roberts  , Alvarez  , Bern  , Goyens  , Rosenthal  , Lachaux  , Shelton  , Sarles  , Sokal
Published: March 2003

To develop prognostic models for identifying children with hepatitis B who are likely to respond to interferon‐α (IFN‐α) or to spontaneously seroconvert, we evaluated results of a multinational controlled trial comprising 70 children with chronic hepatitis B who received IFN‐α and 74 children who did not receive therapy. Prognostic models were developed using SMILES (similarity of least squares), which is a data analysis network that incorporates multidimensional relationships in the clinical data of complex diseases. Commonly collected clinical data included age, gender, serum aminotransferase (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) and hepatitis B virus (HBV) DNA levels, and IFN‐α dose. Additional data included pretreatment directional information (e.g. increases or decreases in serum aminotransferase and HBV DNA levels), liver biopsy results, race and transmission mode. Using data available prior to initiation of treatment, the SMILES models achieved prospective predictions of 89% for responders, 96% for non‐responders, 100% for seroconverters and 93% for non‐seroconverters. Although not predictive by themselves, the variables that had the greatest impact on predictions for IFN‐α response were HBV DNA pretreatment direction, baseline HBV DNA, IFN‐α dose and gender. The variables that had the greatest impact on predictions for spontaneous seroconversion were ALT pretreatment direction, baseline HBV DNA level, age and AST pretreatment direction. Therefore, these models may be useful in determining, in children with hepatitis B, the likelihood of response to IFN‐α and spontaneous seroconversion.
Apoptotic cell death does not parallel other indicators of liver damage in chronic hepatitis C patients
Authors: Rodrigues  , Brites  , Serejo  , Costa  , Ramalho  , De Moura M. Carneiro
Published: March 2003

The mechanisms of hepatocyte damage and the events that lead to high rates of chronic liver disease in hepatitis C virus (HCV) infection remain unclear. Recent in vitro studies have suggested that the HCV core protein may disrupt specific signalling pathways of apoptosis. This prompted us to study patients with chronic HCV infection to: determine the extent of apoptosis in the liver; evaluate whether clinical and biochemical data are correlated with histological findings; and to investigate if apoptosis is related to the histological activity of the disease. Twelve patients with chronic hepatitis C were included in the study. Liver histology was scored by using the histological activity index (HAI) of Knodell et al. DNA fragmentation was assessed in liver tissue by the terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick end‐labelling (TUNEL) assay. Routine methods were used to determine serum markers of liver disease. Bile acids were measured in serum and liver by gas chromatography. Patients were placed, according to their HAI score, into group A (3.8 ± 0.3) or group B (7.8 ± 0.8) (P < 0.01). Liver enzymes tended to be higher in group B patients than in patients of group A. Levels of toxic bile acids in serum were greater in patients than in controls (P < 0.01). Chenodeoxycholic acid values were slightly higher in serum and liver of patients in group A. Liver biopsies with low HAI scores showed an increased rate of apoptosis (18.0 ± 4.0 apoptotic cells per field) compared to those with higher HAI scores (6.6 ± 2.1, P < 0.05) or to controls (3.5 ± 0.4, P < 0.01). Hence, less severe liver disease, associated with lower histological grades and biochemistries, as well as increased levels of chenodeoxycholic acid, induces an expanded apoptotic response. The lower apoptotic rate in advanced liver disease may be associated with the high incidence of hepatocellular dysplasia/neoplasia.
Transfusion‐transmissible virus and hepatocellular carcinoma: a case–control study
Authors: Skelton  , Kew  , Yu  , Crookes  , Swanevelder  , Hodkinson
Published: March 2003

Although transfusion‐transmissible virus (TTV) is often present in the serum of patients with acute and chronic non‐A–C liver diseases, its hepatotropism, pathogenicity to the liver and hepatocarcinogenicity have not been proven. We used a case‐control format to compare the prevalence of TTV infection among 148 southern African Blacks with hepatocellular carcinoma and 148 matched hospital‐based controls, and to test for possible interactive effects between this virus and hepatitis B virus (HBV) and hepatitis C virus (HCV) in the development of the tumour. We also determined the prevalence of TTV in 988 blood donors in Gauteng province of South Africa. The presence of TTV DNA in serum samples was detected by using the polymerase chain reaction, Southern hybridization and nucleotide sequencing. Individuals infected with TTV did not have an increased risk of developing hepatocellular carcinoma (relative risk 1.1; 95% confidence limits 0.5–2.4). Moreover, co‐infection with TTV did not further increase the risk of tumour development in patients chronically infected with HBV and/or HCV. TTV was present in the serum of 2.2% of blood donors: 4.0% in Black and 1.5% in White donors. We conclude that TTV is unrelated to the development of hepatocellular carcinoma in Black Africans.
Subacute thyroiditis during treatment with combination therapy (interferon plus ribavirin) for hepatitis C virus
Authors: Paraná  , Cruz  , Lyra  , Cruz
Published: March 2003

Autoimmune thyroiditis has been frequently reported during interferon monotherapy for hepatitis C, but there are few reports concerning subacute thyroiditis. Recently, combination therapy of IFN plus ribavirin has become the preferred therapeutic schedule for chronic hepatitis C. Similarly to interferon monotherapy, there are no reports concerning subacute thyroiditis during combination therapy. We described four episodes of subacute thyroiditis occurring in three patients during antiviral combination therapy. All patients had symptoms compatible with hyperthyroidism, which could be misdiagnosed as IFN side‐effects. The antiviral treatment was continued in all three patients and thyroid function increased progressively with pharmacological treatment for hyperthyroidism. We concluded that subacute thyroiditis may be a complication of combination antiviral therapy and should be investigated in patients presenting with compatible symptoms, in order to differentiate from IFN side‐effects.
Quantitative evaluation of cytomegalovirus DNA in infantile hepatitis
Authors: Funato T. , Satou N. , Abukawa D. , Satou J. , Abe Y. , Ishii K. K. , Iinuma K. , Kaku M. , Sasaski T.
Published: March 2003

We used a PCR method to develop a diagnostic assay for the detection of cytomegalovirus (CMV) DNA in infantile hepatitis, which has been suggested to be associated with CMV infection. CMV DNA was detected in 25 (58.1%) of 43 patients with elevated serum alanine aminotransferase (ALT) levels but no jaundice, and no hepatitis B or C as assessed by conventional PCR. None of the samples from 97 healthy infants tested positive for CMV DNA. We assayed CMV DNA quantitatively in blood using a real‐time PCR system that allowed reproducible detection of at least 10 copies of CMV DNA. When 1 μg of DNA from each blood sample was used in this system, a good correlation was obtained between the calculated and measured copy numbers of CMV DNA. This system detected CMV DNA in 29 patients (67.4%) with liver dysfunction. Serial studies in patients with liver dysfunction revealed that CMV DNA copy number decreased, ultimately to below 10, as the ALT levels normalized. In contrast, no CMV DNA copies were detectable by the real‐time system in any of the samples from control subjects. These results highlight the usefulness of detecting CMV DNA in the diagnosis of infantile hepatitis and indicate that the real‐time quantitative PCR assay may be a valuable tool for monitoring CMV‐associated infantile hepatitis.
Quantification of fibrosis progression in patients with chronic hepatitis C using a Markov model
Authors: Deuffic‐Burban S. , Poynard T. , Valleron A.‐J.
Published: March 2003

The knowledge of fibrosis progression in chronic hepatitis C and the impact of new treatments on progression is limited by the number of available liver biopsies per patient. Moreover, liver biopsies identify a patient's stage of fibrosis at a given point in time, but cannot quantify the time spent in that stage nor the date of transition to that stage. This paper assesses the potential of Markov modelling to overcome these difficulties. The data from interferon‐treated (n=185) and untreated patients (n=102) are analysed to illustrate the power of this technique.

The model accurately reproduced the distributions of patients in the different fibrosis stages at two subsequent biopsies. A quantification of the role of cofactors in the progression of the disease, and the impact of interferon treatment are given. In subjects who are 40 years old and have been infected for 10 years, the model predicted that 274 of 1000 untreated patients, but only 42 of 1000 treated patients, would progress from F0 or F1 to F3 or F4 fibrosis over the next 5 years. The model also confirms that as age and duration of infection increase, the risk of fibrosis progression increases, while the impact of treatment with interferon decreases.

Hence Markov modelling is an accurate tool in the analysis of fibrosis progression in chronic hepatitis C. It will be valuable for the quantification of the effect of new treatments on fibrosis progression in hepatitis C.
Alcohol abstinence does not offset the strong negative effect of lifetime alcohol consumption on the outcome of interferon therapy
Authors: Tabone M. , Sidoli L. , Laudi C. , Pellegrino S. , Rocca G. , Della Monica P. , Fracchia M. , Galatola G. , Molinaro G. C. , Aricò S. , Pera A.
Published: March 2003

summary. Heavy alcohol consumption has been reported to negatively affect the outcome of interferon therapy. We studied the impact of lifetime alcohol consumption in patients with chronic hepatitis C treated with interferon after 6 months of alcohol withdrawal. Alcohol intake was measured when patients with chronic hepatitis C were referred to us for the first time, and from that moment complete abstinence was recommended. After 6 months of abstinence, 150 patients with persistent elevated serum alanine aminotransferase (ALT) have been treated with interferon (IFN)‐α, 3 or 6 summaryU three times per week for 12 months. Univariate and multivariate analysis were performed to identify the predictors of treatment response. Carbohydrate‐deficient transferrin was employed to assess alcoholic abstinence. The sustained response rate felt from 33% in nondrinkers to 20% of mild‐drinkers and to only 9% in heavy drinkers. Drinker patients showed a relapse rate twice as high as that of nondrinkers. According to the multivariate analysis, the strongest independent predictors of nonresponse were genotype 1b infection, age of the patients and their lifetime alcohol intake. Carbohydrate‐deficient transferrin detected at baseline, at 3 months of therapy and at the end of follow‐up gave a positive result only in eight determinations (1.77%), confirming the compliance of patients to our recommendation of alcohol abstinence. Lifetime alcohol consumption has a strong negative effect on the outcome of interferon treatment, mainly in heavy drinkers. A 6‐month period of abstinence may not be sufficient to offset this negative effect on treatment outcome.
Fatigue in patients with chronic hepatitis C
Authors: Poynard T. , Cacoub P. , Ratziu V. , Myers R. P. , Dezailles M. H. , Mercadier A. , Ghillani P. , Charlotte F. , Piette J. C. , Moussalli J. ,   for the multivirc group*
Published: March 2003

summary. In numerous studies of symptoms in patients with chronic hepatitis C there has been no systematic assessment of both fatigue and extrahepatic manifestations. Our objective was to assess the prevalence of fatigue in patients with hepatitis C virus (HCV) infection, and to identify associations between fatigue and clinical and biological hepatic and extrahepatic manifestations. We studied 1614 patients. Data were prospectively recorded during the first visit of patients infected with HCV and the prevalence of fatigue and its association with dermatological, rheumatological, neurological and nephrological manifestations; diabetes; arterial hypertension; auto‐antibodies, and cryoglobulinaemia were assessed. Then, using multivariate analysis, we identified demographic, biochemical, immunological, virological, and histological factors associated with the presence of fatigue.

Fatigue was present in 53% of patients (95% confidence interval 51–56). In 17% of patients (95% confidence interval 15–19) fatigue was severe, impairing activity. Five other extrahepatic manifestations had a prevalence above 10% including, in decreasing order: arthralgia, paresthesia,

myalgia, pruritus, and sicca syndrome. In univariate and multivariate analyses, fatigue, in comparison with the absence of fatigue, was associated with female gender, age over 50 years, cirrhosis, depression and purpura. Independent of these associations, fatigue was associated with arthralgia, myalgia, paresthesia, sicca syndrome and pruritus. The prevalence of fibromyalgia (as defined by the association of fatigue with arthralgia or myalgia) was 19% (95% confidence interval 17–21). There was no significant association between fatigue and the following characteristics: viral load or genotype, alcohol consumption, abnormal thyroid function, and type and level of cryoglobulinaemia. Hence, fatigue is the most frequent extrahepatic manifestation in patients infected with HCV. Fatigue is independently associated with female gender, age over 50 years, cirrhosis, depression and purpura.
Dietary strategies of Old World Fruit Bats (Megachiroptera, Pteropodidae): how do they obtain sufficient protein?
Authors: Courts S. E.
Published: March 2003

The complexity of dietary strategies evolved by megachiropterans (Pteropodidae) is gaining recognition, although there are relatively few reports of feeding habits other than frugivory, and even fewer of non‐herbivorous ones. This paper reviews the information obtained so far on how the diets of Old World fruit bats may provide them with sufficient protein, as most fruits are known to be low in this vital nutrient. There is evidence to suggest that pollen, leaves or insects may provide wild pteropodids with the extra protein that studies in captivity have shown to be necessary.
The use of trackway counts to establish an index of deer presence
Authors: Mayle B. A. , Putman R. J. , Wyllie I.
Published: March 2003

The use of transect counts of faecal pellet groups together with counts of trackways crossing the perimeter of a woodland block were investigated as a means of establishing an index of deer presence and relative abundance. Surveys were undertaken in 38 sites in agricultural landscapes in south and east England. Correlations between trackways per 100 m and faecal pellet groups per 100 m were highly significant when all sites or sites with Roe Deer (Capreolus capreolus) as the main species present were considered. Deer densities were estimated from the faecal pellet group counts and the results used to calibrate the method. Trackway counts as described provide a quick and effective means of establishing a scalar index of deer presence.
Catastrophic events and recovery from low densities in populations of otariids: implications for risk of extinction
Authors: Gerber Leah R. , Hilborn Ray
Published: March 2003

Two key factors in a population's risk of extinction are major population declines induced by natural or anthropogenic events (catastrophes) and whether the population's rate of growth increases or decreases at very low abundance levels. These two elements should be included in any population viability analysis (PVA), but estimates of the frequency and intensity of catastrophic events and data on the dynamics of low population densities are difficult to obtain. We examined the literature on population dynamics of otariids (fur seals and sea lions), to determine how frequently populations are subjected to major population declines, and to what extent depleted populations recover from low population size. We present frequency distributions for percentage declines for otariid life‐stages (pup, juvenile, adult female and male), and describe eight examples of events leading to a population decline of 50% or greater among otariids. We found that numerous otariid populations have been reduced to very low densities by exploitation (low enough to be thought extinct) and have recovered to levels where they are no longer at risk of extinction. This suggests that the reduction in population rate of increase at low densities in otariid populations may not be strong.
The use of willingness‐to‐pay approaches in mammal conservation
Authors: White Piran C. L. , Bennett Alison C. , Hayes Emma J. V.
Published: March 2003

With limited monetary resources available for nature conservation, policy‐makers need to be able to prioritize conservation objectives. This has traditionally been done using qualitative ecological criteria. However, since declines in species and habitats are largely the result of socio‐economic and political forces, human preferences and values should also be taken into account. An environmental economics technique, contingent valuation, provides one way of doing this by quantifying public willingness‐to‐pay towards specific conservation objectives.

In this paper, the use of this approach for quantifying public preferences towards the UK Biodiversity Action Plans for four different British mammal species is considered. The species included are the Red Squirrel Sciurus vulgaris, the Brown Hare Lepus europaeus, the Otter Lutra lutra and the Water Vole Arvicola terrestris. Willingness‐to‐pay for conservation was increased by the inclusion of the Otter among the species, membership of an environmental organization and awareness of the general and species‐specific threats facing British mammals. It was reduced by the presence of the Brown Hare among the species being considered.

These findings for British mammals are compared with other willingness‐to‐pay studies for mammal conservation worldwide. Willingness‐to‐pay tends to be greater for marine mammals than terrestrial ones, and recreational users of species (tourists or hunters) are generally more willing than residents to pay towards species conservation. The choice of technique for eliciting willingness‐to‐pay from respondents is also shown to be highly significant.

Willingness‐to‐pay values for British mammals derived from contingent valuation are sensitive to the species included rather than merely symbolic. This indicates that, with care, such measures can be used as a reliable means of quantifying public preferences for conservation, and therefore contributing to the decision‐making process. However, irrespective of the internal consistency of contingent valuation, the validity of the approach, especially for use in nature conservation, is disputed. Willingness‐to‐pay is likely to reflect many interrelated factors such as ethical and moral values, knowledge and tradition, and monetary values may not be an adequate representation of these broader considerations. Willingness‐to‐pay approaches should therefore be used in addition to, rather than in place of, expert judgements and more deliberative approaches towards policy decision‐making for conservation.
Abundance of Lutzomyia ovallesi but not Lu. gomezi (Diptera: Psychodidae) correlated with cutaneous leishmaniasis incidence in north‐central Venezuela
Authors: FELICIANGELI DORA M. , RABINOVICH JORGE
Published: March 2003

In north‐central Venezuela Lutzomyia gomezi and Lu. ovallesi are the main endophilic/anthropophilic species of phlebotomine sandflies implicated as vectors of cutaneous leishmaniasis (CL). Lutzomyia ovallesi has been found infected with Leishmania braziliensis (1.2%) and less often with Le. mexicana (0.07%), while Le. braziliensis infections have also been found in Lu. gomezi (0.47%). We investigated population densities of these sandflies using two sampling methods with four series of collections between January 1991 and March 1995 at El Ingenio, Miranda State. All‐night outdoor collections from a Shannon trap were correlated with indoor collections from CDC light–traps by linear regression, which proved to be statistically significant for both species. Estimated numbers of female sandflies per house per night were found to be proportional to monthly precipitation (i.e. rainfall), with a lag time of seven months for Lu. ovallesi and of six months for Lu. gomezi. Predominance of Lu. ovallesi over Lu. gomezi (c. 10 :1 ) was observed throughout the year, with the number of infected females estimated as 0.043 ± 0.047 Lu. ovallesi and 0.0085 ± 0.0124 Lu. gomezi per CDC trap per house per night (ratio ∼ 5:1). The mean rate of new CL cases per house per year and sandfly abundance were correlated by linear regression, showing a statistically significant relationship for Lu. ovallesi but not for Lu. gomezi. The negative intercept indicated that, on average, the CDC trap density exceeds 800 Lu. ovallesi females/house/year before new CL cases occur at El Ingenio.
The efficacy of entomopathogenic nematodes for controlling housefly infestations of intensive pig units
Authors: RENN
Published: March 2003

The efficacy of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis after formulation into a housefly bait was compared with a commercial bait formulation of methomyl for the control of houseflies in a U.K. pig farm. The housefly infestation was confined to the farrowing unit, which consisted of ten farrowing houses, where two adjacent houses were sequentially re‐stocked with pregnant sows at weekly intervals. Shortly after re‐stocking, one house was baited with one of the nematode species and the other with methomyl. Significantly fewer flies (P < 0.05) were counted in the houses baited with either S. feltiae or H. megidis than those baited with methomyl. The efficacy of S. feltiae sprayed on to the manure was also compared with methomyl bait. Counts of houseflies carried out in the farrowing cycle before this treatment were not significantly different (P > 0.05); however, significantly fewer flies (P < 0.05) occurred after S. feltiae was sprayed. The efficacy of encapsulated S. feltiae was also compared with methomyl bait and no significant difference was observed (P > 0.05).
Use of climatic data and satellite imagery to model the abundance of Culicoides imicola, the vector of African horse sickness virus, in Morocco
Authors: BAYLIS  , BOUAYOUNE  , TOUTI  , HASNAOUI EL H.
Published: March 2003

African horse sickness (AHS) is a vector‐borne, infectious disease of equids caused by African horse sickness virus (AHSV) . The only proven field vector of the virus is the biting midge Culicoides imicola. Following a recent epizootic (1989–91) of AHS in Morocco, light traps and automatic weather stations were operated for 2 years at twenty‐two sites distributed over much of the country. The annually‐averaged mean daily trap catch of C. imicola at these sites was negatively correlated with wind speed, and positively correlated with the average and mean annual minimum NDVI (Normalized Difference Vegetation Index, a remotely sensed measure of vegetation activity). There were no significant correlations between the mean daily trap catch and air temperature, soil temperature, relative humidity, saturation deficit, rainfall, altitude or the mean annual maximum or range of NDVI. The best two‐variable model, which combined WindspeedMnAvMn (the average daily minimum wind speed of the least windy month) and NDVImin (the average annual minimum NDVI) as predictors, explained over 50% of the variance in the annually‐averaged mean daily trap catch of C. imicola. There was a significant, positive correlation between minimum wind speed at night and the daily mortality rate of adult female C. imicola and it is suggested that the relationship between wind speed and the abundance of C. imicola arises from effects on adult mortality or dispersal. Considering several climatic variables, in North Africa NDVImin was most significantly correlated with total annual rainfall. It is suggested that the relationship between NDVImin and the abundance of C. imicola arises from the impact of soil moisture on both. It is proposed that areas of Morocco with higher levels of soil moisture in late summer or autumn provide more, larger and/or more enduring breeding sites for C. imicola, as well as supporting more photosynthetically active vegetation and hence having higher NDVI.
A new species of the Simulium damnosum complex from Uganda, and comparative morphology of the tarsal claws in females of this complex
Authors: KRÜGER  , NURMI  , GARMS
Published: March 2003

The female, male, pupa and larva of Simulium (Edwardsellum) pandanophilum sp. nov. (Diptera: Simuliidae) from western Uganda are described. Diagnostic features are the shape of the tarsal claws of females and, cytogenetically, new intraspecific inversions on chromosomes I and II. Simulium pandanophilum is assigned to the Simulium damnosum complex. Different tarsal claw shapes of West African members of the S. damnosum complex are also described.
Sibling species distributions of the Simulium damnosum complex in the West African Onchocerciasis Control Programme area during the decade 1984–93, following intensive larviciding since 1974
Authors: Boakye D. A. , Back C. , Fiasorgbor G. K. , Sib A. P. P. , Coulibaly Y.
Published: March 2003

Abstract.During the decade from 1984 to 1993, nine species of the Simulium damnosum complex of blackflies (Diptera: Simuliidae) were identified from the area covered by the Onchocerciasis Control Programme. These were S. damnosum s.s., S. dieguerense, S. konkourense, S. leonense, S. sanctipauli, S. sirbanum, S. soubrense, S. squamosum, and S. yahense. Some of these species were found to consist of two chromosomal variant populations. These were S. konkourense‘Konkouré' and ‘Menankaya' forms, S. sanctipauli sensu stricto and‘Djodji' form, S. soubrense‘Chute Milo' and ‘Beffa' forms. The distribution of these twelve cytological taxa was assessed in relation to the two main vegetation zones of West Africa (forest and savanna), topography, river size and other factors. The range of each species was influenced by seasonal climatic changes in wind movement and river water level.

The most widely distributed species were S. sirbanum and S. damnosum s.s., associated with savanna areas, recorded from all river basins. Simulium dieguerense was restricted mainly to Western Mali on the Rivers Bafing and Bakoye in the Senegal River basin. Simulium squamosum was identified from rivers draining mountainous areas in both the forest and savanna zones. Simulium yahense was found in small permanent rivers along a wide forested band parallel to the coast and was absent from the plains of Togo and Benin. Members of the S. sanctipauli subcomplex had restricted distributions except for S. sanctipauli s.s., which was widespread in large rivers of the forest zone from Sierra Leone to the Volta Lake in Ghana. Simulium soubrense‘Beffa' form occurred in Togo and Benin, S. soubrense‘Chutes Milo' form in Guinea, both ‘Konkouré' and ‘Menankaya' forms of S. konkourense occurred predominantly in Guinea and S. leonense in Sierra Leone. The relevance of the distribution maps and the importance of the data bank to vector control larvicidal operations are discussed.
Field responses ofGlossina austenito sticky panels on Unguja Island, Zanzibar
Authors: Vreysen Marc J. B. , Zhu Zeng‐Rong , Saleh Khalfan M.
Published: March 2003

Abstract.Two designs of cross‐shaped sticky panels (XT and XLP) were compared with the royal blue–white legpanel (LPBuWh) in the Jozani forest on Unguja Island as trapping devices for male Glossina austeni. Single coloured royal blue (XTBu) and bi‐coloured royal blue–white XT (XTBuWh) caught more than twice as many male G. austeni as the LPBuWh, whereas single coloured black XT trapped significantly fewer flies (10%) than the control LPBuWh. XT's in various horizontal and diagonal blue–white configurations likewise trapped more flies than the LPBuWh, except a horizontally striped blue–white XT which trapped fivefold fewer flies than the LPBuWh. Cross‐shaped LP in the blue–white (XLPBuWh) and black–white (XLPBlWh) combination scored significantly better than the control LPBuWh. Similar fly numbers were trapped with XTBuWh and XLPBuWh. Long‐term trapping data indicated that the XTBu, XTBuWh and XLPBuWh were three‐ to fourfold more effective in trapping female flies than the LPBuWh.

The landing bias on bi‐coloured panels was low in the blue–white but more pronounced in the blue–black and white–black combinations and was affected by the type of sticky panel used. A high proportion (49%) of the flies alighted on the bottom corners of the XTBu panel, but landing positions were more scattered if white was added.

Increasing the width of the XTBu from 70 to 120 cm improved the catch by a factor of two as compared with standard sized XTBu. The effect of doubling the height of the XT on total fly catch was negligible.

At present, it is the XTBu which can be recommended as the best trapping device for male and female G. austeni.
Induced immunity against the mosquito Anopheles stephensi: reactivity characteristics of immune sera
Authors: Almeida A. P. G. , Billingsley P. F.
Published: March 2003

This study shows the progression of immune responses in mice during five sequential immunizations with Anopheles stephensi mosquito extracts, characterized by ELISA, Western blot and immunohistochemistry. When exposed repeatedly to mosquito bites, control mice developed antibodies which reached titres of 1 : 105, reacted weakly in Western blot analysis and were localized to the salivary glands. Mice immunized with mosquito head plus salivary glands, midgut, ovary, fat body, midgut microvilli (Mv) and midgut basolateral plasma membrane (Blm), showed increased titre with each successive boost. Epitopes were shared between sera or were specific to the immunizing or heterologous extract. Anti‐Mv and Blm sera recognized proteins labelled by anti‐midgut serum and gave specific reactions with the midgut and head. Cross‐reactivity was confirmed immunohistochemically.
Visual responses of Musca domestica to pheromone impregnated targets in poultry units
Authors: Chapman J. W. , Knapp J. J. , Goulson D.
Published: March 2003

Field trials investigating the effect of visual cues on catches of Musca domestica (Diptera: Muscidae) at toxic targets impregnated with the female sex pheromone (Z)‐9‐tricosene, were conducted in a caged‐layer deep‐pit poultry unit in southern England. Targets treated with azamethiphos and baited with 2.5 g of 40% (Z)‐9‐tricosene impregnated beads caught significantly greater numbers of M. domestica than control targets. The greater attractiveness of the pheromone impregnated targets persisted for at least 5 weeks. The addition of longitudinal black stripes, or a regularly spaced pattern of black spots, to the white targets had no effect on catch rates. However, a pattern of clustered black spots, designed to imitate groups of feeding M. domestica, significantly increased target catches; this effect was particularly pronounced in the targets impregnated with (Z)‐9‐tricosene. Trials comparing the attractiveness of white and fluorescent yellow pheromone‐treated targets under two different lighting regimes indicated that M. domestica does not have a significant preference for either colour. The implications of these results in relation to the control of M. domestica populations in poultry units are discussed.
Multiple host feeding in field populations of Anopheles culicifacies and An. subpictus in Sri Lanka
Authors: Amerasinghe P. H. , Amerasinghe F. P.
Published: March 2003

A histological technique was used to detect the multiple blood‐feeding of female mosquitoes, within the same gonotrophic cycle, in field populations of the malaria vectors Anopheles culicifacies and An.subpictus (Diptera: Culicidae) at a village in the low country of Sri Lanka, during 1994–96. Among 3306 An.culicifacies and 871 An.subpictus engorged females examined, respectively, 34.4% and 30.4% were multiple‐fed. In these two species, double meals accounted for 92.7% and 89.5%, and triple meals for 7.3% and 10.5% of multiple meals, respectively. More females of An.culicifacies (53.7%) than An.subpictus (44.5%) multiple‐fed on different nights. Multiple feeding rates in the two species were independent of sample size and field abundance. In An.culicifacies, but not An.subpictus, these rates were proportional to ambient temperature but not to humidity. Bloodmeal ELISA showed that 8.3% of 242 An.culicifacies were human‐fed and 80% of these (i.e. 6.6%) were concurrently bovid‐fed. Combining the histological and ELISA data, it was estimated that multiple feeding involving a human host had occurred in 7.2% of the blood‐feeding An.culicifacies population at this study site. Only 1.2% of 406 An.subpictus were human‐fed and all of these were concurrently bovid‐fed. Multiple bloodfeeding within the same gonotrophic cycle was attributed to a local ‘frequent feeding strategy’ in these primarily zoophagic and endophilic malaria vectors. Unfortunately this strategy enhances their human‐biting rate and hence their vectorial capacity.
Olfactory responses to attractants and repellents in tsetse
Authors: Voskamp K. E. , Everaarts E. , Den Otter C. J.
Published: March 2003

The aims of this study were to investigate how antennal olfactory cells of tsetse (Diptera: Glossinidae) code odour quality and how they are able to discriminate between attractive and repellent odours. For Glossina pallidipes Austen, a survey is presented of the cells’ responses to attractive (1‐octen‐3‐ol, acetone, 3‐methylphenol, carbon dioxide) and repellent stimuli (2‐methoxyphenol, acetophenone, lactic acid, naphthalene). In addition, the responses of these cells to binary mixtures and the dose–response curves of 1‐octen‐3‐ol, 3‐methylphenol, 2‐methoxyphenol and acetophenone are presented. A minority of the cells responded to one attractant or repellent only, whereas the vast majority were excited by more than one of the attractive and/or repellent stimuli. It is proposed that the peripheral olfactory cells of tsetse discriminate between different compounds via an across‐fibre pattern coding, in which the cells that specifically code for attractants or repellents may play a substantial role in composing a unique excitation pattern that informs the central nervous system about the specificity of odours.
Interspecific competition between sibling species larvae of Anopheles arabiensis and An. gambiae
Authors: Schneider P. , Takken W. , Mccall P. J.
Published: March 2003

Mosquito larvae of the sibling species Anopheles arabiensis Patton and An. gambiae Giles sensu stricto (Diptera: Culicidae) were investigated for interspecific competition. Single‐species and mixed‐species populations were reared at 27°C from the first instar to pupation at different densities (100, 200 or 400 larvae/200 cm2 tray) with a constant amount of food, 0.2 mg/larva/day. Pupae obtained from mixed populations were identified to species using PCR. Both species had a 1 : 1 sex ratio at pupation. Development time to pupation averaged about one day less for An. arabiensis compared to An. gambiae, ranging from 0.93–1.49 d for males and from 0.44–0.84 d for females in single populations. In mixed species populations the difference for males ranged from 0.99–1.58 d and for females from 0.93–1.62 d. Survival rates of An. gambiae s.s. were significantly higher than those of An. arabiensis in both the single‐species and mixed‐species populations. Mixed‐species rearing did not have an effect on the survival of An. gambiae, whereas the mortality rate of An. arabiensis was significantly higher in mixed populations than when only this species was reared at the same densities, suggesting a competitive disadvantage for An. arabiensis in mixed populations. High proportions of larvae (4–35%) were lost during development; these losses could not be accounted for by corpses found in the rearing pans. The possibility of cannibalism was investigated by rearing each species separately in small containers (five per 50 ml), inspected every 6 h, but no cannibalism was detected at any stage of development in either species. It was concluded that, under these experimental circumstances, interspecific competition between both species did occur but with a detrimental effect on An. arabiensis only. Relevance of these findings to the ecology of both species in the field is discussed briefly.
Effects of temperature and larval diet on development rates and survival of the dengue vector Aedes aegypti in north Queensland, Australia
Authors: Tun‐Lin W. , Burkot T. R. , Kay B. H.
Published: March 2003

Immature development times, survival rates and adult size (wing‐lengths) of the mosquito Aedes aegypti (L.) (Diptera: Culicidae) were studied in the laboratory at temperatures of 10–40°C. The duration of development from egg eclosion (hatching of the first instar) to adult was inversely related to temperature, ranging from 7.2 ± 0.2 days at 35°C to 39.7 ± 2.3 days at 15°C. The minimum temperature threshold for development (t) was determined as 8.3 ± 3.6°C and the thermal constant (K) was 181.2 ± 36.1 day‐degrees above the threshold. Maximum survival rates of 88–93% were obtained between 20 and 30°C. Wing‐length was inversely related to temperature. The sex ratio (♀:♂) was 1 : 1 at all temperatures tested (15, 20, 25 and 35°C) except 30°C (4 : 3).

Under field conditions at Townsville and Charters Towers, north Queensland, the duration of immature development varied according to the container position (i.e. shaded or exposed) and the availability of food resources, as well as inversely with temperature. These data indicate that containers with an abundance of organic matter (e.g. those used for striking plant cuttings) or those amongst foliage or under trees (e.g. discarded plastic tubs and tyres) tended to produce the largest adult Ae. aegypti, which had faster development and better immature survival. As such progeny have been linked to a greater risk of dengue transmission, it would seem important to focus on control of such containers.
Repellency of deet to nymphs of Triatoma infestans
Authors: Alzogaray R. A. , Fontan A. , Zerba E. N.
Published: March 2003

The repellency of N,N‐diethyl‐3‐methylbenzamide (deet) to Triatoma infestans (Klug) (Hemiptera: Reduviidae) was evaluated using third‐instar nymphs and a video tracking technique. Three experimental designs were used: (a) the test arena floor was divided into two halves, only one of which was treated with deet; (b) the arena floor was divided into an inner circle and an outer ring, only the latter treated with deet; (c) half of the test arena was covered by a filter paper roof treated with deet (out of reach of the nymphs). In all three types of experiment, a repellent effect was demonstrated proportional to the dose of deet. When a host (pigeon) was shielded by deet‐treated gauze, the rate of blood‐feeding by the nymphs was inhibited. Topical pre‐treatment of the nymphs with N‐ethylmaleimide, to block chemoreception, inhibited the repellency.
Shared salinity tolerance invalidates a test for the malaria vector Anopheles farauti s.s. on Guadalcanal, Solomon Islands
Authors: Foley D. H. , Bryan J. H.
Published: March 2003

Among the Punctulatus Group of Anopheles mosquitoes (Diptera: Culicidae), first‐instar larvae of the medically unimportant freshwater Anopheles farauti species No. 7 survives a seawater tolerance test (SST) that was previously thought to be diagnostic for the saltwater‐tolerant malaria vector species, An. farauti Laveran s.s. Salt tolerance in these two closely related isomorphic species appears to be a shared derived character within the Farauti Complex. Failure to differentiate An. farauti s.s. from An. farauti No.7 will overestimate potential malaria vector numbers and waste limited larval control resources. Use of the SST should therefore be discontinued on Guadalcanal and other techniques such as allozyme electrophoresis used instead.