bluuebunny/crossref_metadata_2025 huggingface dataset:
Viral and host factors in the prediction of response to interferon‐α therapy in chronic hepatitis C after long‐term follow‐up
Authors: Knolle P. A. , Kremp S. , Höhler T. , Krummenauer F. , Schirmacher P. , Gerken G.
Published: March 2003

Acute infection with hepatitis C virus (HCV) develops into a chronic hepatitis in about 50–70% of patients. Treatment of these patients with interferon‐α (IFN‐α) results in a sustained long‐term response in only 15–20% but causes numerous unwanted side‐effects in a higher percentage of patients. The aim of our study was to define host or viral parameters that would allow identification of responders and non‐responders to IFN‐α prior to the onset of treatment. We studied a group of 87 patients suffering from chronic hepatitis C who were treated with IFN‐α. After long‐term follow‐up, 18 patients (21%) showed a sustained response to IFN‐α therapy (normalization of serum transaminases and loss of viral RNA from serum) for up to 7 years after therapy had ceased. By univariate and multivariate analyses, no host factors were found to be predictive of response to therapy. Neither the degree of inflammation or fibrosis in liver biopsy samples obtained before treatment nor immunogenetic factors (major histocompatibility complex II haplotype and tumour necrosis factor‐α promoter polymorphism) were associated with response to therapy. In contrast, viral parameters showed a strong association with response to therapy. HCV genotype 3 was found significantly more frequently in responders (P = 0.034), and mean HCV RNA concentration was lower in responders (3.1 × 104) than in non‐responders (2.5 × 105) (P = 0.01). By multivariate analysis, both HCV genotype and HCV RNA concentration were independent predictors of response to therapy. However, exact prediction of response to treatment for an individual patient was not possible on the basis of pretreatment viral RNA concentration or viral genotype. The best association with response to therapy was found to be clearance of HCV RNA from serum 3 months after the start of treatment (32 of 34 partial and sustained responders vs 0 of 53 non‐responders; P = 0.001). In conclusion, determination of pretreatment viral factors, but not host factors, was significantly correlated with treatment response but did not give an accurate prediction for patients, whereas clearance of HCV RNA from serum after 3 months of therapy was predictive of response to therapy.
Characterization of the T‐ and B‐cell immune response to a new recombinant pre‐S1, pre‐S2 and SHBs antigen containing hepatitis B vaccine (Hepagene™); evidence for superior anti‐SHBs antibody induction in responder mice
Authors: Jones C. D. , Page M. , Bacon A. , Cahill E. , Bentley M. , Chatfield S. N.
Published: March 2003

Hepagene™ is a novel recombinant particle consisting of the pre‐S1, pre‐S2 and small surface (SHBs) antigens (Ag) of the hepatitis B virus (HBV) and is adjuvanted with alhydrogel in the final formulation. It has been primarily developed to enhance anti‐SHBs antibody titres in inadequate responders, to conventional SHBsAg vaccines. Since non‐compliance is also a problem with existing HBV vaccine schedules, the ability to accelerate current immunization regimens to provide more rapid protection has also been an important objective. Here we describe the T‐ and B‐cell responses to Hepagene™ in two strains of responder mouse (BALB/c and SWR/J).
Hepatitis viruses and the safety of blood donations
Authors: Gerlich W. H. , Caspari G.
Published: March 2003

Since the beginning of blood transfusions concomitant transmission of viral hepatitis has been a frequent and serious side‐effect. A first measure to reduce the frequency of transmission was the screening of blood donors for elevated levels of liver enzymes in the blood, which was introduced in Germany in the 1960s, but not in most other countries. After the discovery of hepatitis B virus (HBV), donors in all countries have been screened since the 1970s for its surface antigen (HBsAg). When it was realized that there was at least one other type of virus that was even more frequently transmitted, screening for liver enzymes and HBV antibodies (anti‐HBc) was introduced as a surrogate marker in most, but not all, countries in the 1980s. Furthermore, donors at risk for parenterally transmitted viruses were excluded. The discovery of the hepatitis C virus (HCV) genome and the development of sensitive anti‐HCV assays has meant that reliable detection of persistently infected HCV carriers has been possible since 1991. Recently infected donors, however, are infectious for several weeks or months before anti‐HCV is detectable. Therefore, starting in April 1999 all donations in Germany have to be tested, by nucleic acid amplification tests, for the presence of HCV RNA, although preliminary experience shows that such recent HCV infections are very rare. Newly detected viruses, named GBV‐C or HGV and TTV, have been detected in patients with non‐A‐E post‐transfusion hepatitis, but their association with the disease seems to be coincidental. These viruses cause persistent viraemia and are quite prevalent world‐wide, but do not cause any known disease. At present, transfusion‐transmitted hepatitis has been virtually eliminated, and any improvement in safety will be very small and will require huge costs.
Hepatitis G virus infection in renal transplant recipients
Authors: Isaacson A. H. , Bhardwaj B. , Qian K. , Davis G. L. , Kato T. , Mizokami M. , Lau J. Y. N.
Published: March 2003

To determine the prevalence and clinical significance of hepatitis G virus (HGV)/GB virus C (GBV‐C) infection in renal transplant recipients, prospectively collected serum samples from a cohort of cadaveric renal transplant patients were studied for the presence of HGV RNA using a sensitive reverse transcription ‘nested’–polymerase chain reaction (RT–PCR) based on primers derived from the 5’ untranslated region. All positive PCR amplicons were sequenced bidirectionally and aligned. The nucleotide substitution rate was estimated by the 6‐parameter method, and a phylogenetic tree was constructed using the Neighbour‐joining method. HGV RNA was detected in 11/93 (12%) patients pretransplant and in 15/90 (17%) patients 1–4 years post‐transplant. All PCR amplicons were confirmed to be specific for HGV by sequencing. Phylogenetic tree construction revealed that 17 PCR amplicons had sequences related to HGV and one had a sequence related to GBV‐C. Two HGV RNA‐positive patients pretransplant became HGV RNA negative post‐transplant, and seven HGV RNA‐negative patients pretransplant became HGV RNA positive post‐transplant. There was no relationship between hepatitis C virus (HCV) and HGV infection. There were also no differences in age, gender distribution, ethnic origin, the total number of blood units transfused and either graft or patient survival between patients who were positive or negative for HGV RNA. We conclude that HGV infection is common among renal transplant candidates and recipients. Most of the isolates had sequences related to the HGV prototype. HGV infection does not appear to adversely affect clinical outcome in renal transplant recipients during early follow‐up.
Translation of hepatitis C virus RNA
Authors: Hellen C. U. T. , Pestova T. V.
Published: March 2003

The 341‐nucleotide 5’ non‐translated region is the most conserved part of the hepatitis C virus (HCV) genome. It contains a highly structured internal ribosomal entry site (IRES) that mediates cap‐independent initiation of translation of the viral polyprotein by a mechanism that is unprecedented in eukaryotes. The first step in translation initiation is assembly of eukaryotic initiation factor (eIF) 3, eIF2, GTP, initiator tRNA and a 40S ribosomal subunit into a 43S preinitiation complex. The HCV IRES recruits this complex and directs its precise attachment at the initiation codon to form a 48S complex in a process that does not involve eIFs 4A, 4B or 4F. The IRES contains sites that bind independently with the eIF3 and 40S subunit components of 43S complexes, and structural determinants that ensure the correct spatial orientation of these binding sites so that the 48S complex assembles precisely at the initiation codon.
Oral prostaglandin (PGE2) therapy for chronic viral hepatitis B and C
Authors: Hyman A. , Yim C. , Krajden M. , Read S. , Basinski A. S. H. , Wanless I. , Levy G. , Heathcote J.
Published: March 2003

The cytoprotective effects of prostaglandins have been utilized in the prevention of hepatitis B virus reactivation after liver transplantation. This pilot study evaluated the effects of oral prostaglandin E2 (PGE2) in chronic viral hepatitis B and C. Twenty patients with chronic hepatitis B and 20 patients with chronic hepatitis C received 4mgday–1 PGE2 for 6 months. The lymphocyte antiviral enzyme 2’,5’‐oligoadenylate synthetase (2’,5’‐OAS) and peripheral blood monocyte procoagulant activity (PCA) were measured before, during and after the treatment. Three of 20 hepatitis B and five of 20 hepatitis C patients withdrew from the study. Eight of 17 hepatitis B patients responded: in seven of these eight patients, serum alanine aminotransferase (ALT) levels normalized; loss of viral replication was sustained in all eight patients; and seroconversion from hepatitis Be antigen (HBeAg) to hepatitis Be antibody (HBeAb) positivity occurred in seven patients over the 48‐week duration of this study. In 14 of the 15 hepatitis C patients, hepatitis C virus (HCV) RNA remained detectable and the serum ALT levels remained elevated. 2’,5’‐OAS levels and PCA values did not correlate with other markers of response to PGE2 therapy in either chronic hepatitis B or C. In summary, PGE2 was associated with sustained loss of viral replication in 47% of chronic hepatitis B patients; no beneficial effects were apparent in chronic hepatitis C.
Replication status and histological features of patients with triple (B, C, D) and dual (B, C) hepatic infections
Authors: Mathurin  , Thibault  , Kadidja  , Ganne‐Carrié  , Moussalli  , El Younsi  , Di Martino  , Lunel  , Charlotte  , Vidaud  , Opolon  , Poynard
Published: March 2003

In patients with multiple hepatotropic viral infections (B and C, or B, C and D), the reciprocal influence of each virus remains controversial. The aims of this study were twofold: first, to determine the impact of multiple infection on the replication status of B, C and D viruses and on histological features; and second, to compare patients with multiple infection to patients infected only with the hepatitis C virus (HCV). We retrospectively included 50 patients with multiple infection and 50 control HCV patients, who were matched on independent factors associated with fibrosis, such as age, gender, alcohol consumption and duration of infection. The replication status of hepatitis B virus (HBV), HCV and hepatitis D virus (HDV), and histological lesions, were determined. In patients with multiple infection, HCV RNA was present less frequently (44% vs 98%, P < 0.001) and the prevalence of cirrhosis was higher (35% vs 8%, P < 0.001). Among patients with triple infection (n = 16), HBV replication was observed in 25%, HCV RNA was detectable in only two (P < 0.0001) and HCV viremia was significantly lower than in the matched HCV patients (0 vs 54.7, P < 0.0001). Among patients with dual infection (n = 34), HCV RNA was present less frequently in those with serological markers of active HBV infection than in those without (30% vs 79%, P = 0.01). Hence, multiple infection is associated with a decrease of HCV replication. Cirrhosis seems to be more frequently observed in patients with multiple infection. In patients with triple infection, serum HCV RNA and markers of HBV replication were absent in 80%, suggesting that HDV acts as a dominant virus. In patients with dual infection, HBV and HCV exert an alternative, dominant replication.
Intrahepatic transfusion‐transmitted virus detected by in situ hybridization in patients with liver diseases
Authors: Jiang  , Luo  , He
Published: March 2003

Transfusion‐transmitted virus (TTV) has been identified from patients with post‐transfusion hepatitis of unknown aetiology, but the clinical relevance remains unclear. The aim of this study was to evaluate TTV in liver. We studied 15 patients with hepatitis non‐A–E and 44 with hepatitis B virus (HBV). The nested polymerase chain reaction (PCR) with primers corresponding to the conserved region of the published TTV genome was employed to amplify TTV fragments in serum, and in situ hybridization was used to detect TTV in biopsied liver specimens. TTV DNA was detected in serum from six (40%) of 15 patients with hepatitis of unknown aetiology and from 16 (36.4%) of 44 patients with chronic hepatitis B, respectively. The intrahepatic viral fragment was detected in 17 (77.3%) of 22 patients with TTV in serum. There was no statistical difference in the prevalence of TTV infection between the two groups (hepatitis non‐A–E 40% vs HBV 25%, P > 0.75). When patients in both groups, with and without TTV, were compared, no differences were found in serum alanine aminotransferase (ALT) levels (hepatitis non‐A–E: 131.5 ± 66.6 vs 244.2 ± 257.4, P=0.955; HBV: 240.1 ± 418.9 vs 214.6 ± 276.7 U l−1, P=0.761) or histological activity index (grade) score (hepatitis non‐A–E: 6.4 ± 5.5 vs 5.6 ± 5.9, P=0.689; HBV: 5.6 ± 3.7 vs 5.5 ± 3.7, P=0.345). HBV DNA levels in patients with and without TTV co‐infection did not differ significantly (300 ± 776.4 μg ml−1vs 97.1 ± 160.5 μg ml−1, P=0.980). Hence, TTV does exist in liver, but plays no role in hepatitis or aggravation of liver damage when co‐infected with HBV.
Treatment of chronic hepatitis C virus infection in patients with cirrhosis
Authors: Zeuzem
Published: March 2003

Chronic hepatitis C virus (HCV) infection eventually leads to cirrhosis in 20–30% of patients and to hepatocellular carcinoma (HCC) in 1–5% of patients. Rates of sustained virological response with standard interferon‐α (IFN‐α) are low in patients without cirrhosis (generally < 20%) and are even lower in those with cirrhosis. Combination therapy with IFN and ribavirin improves response rates in patients with chronic hepatitis C without cirrhosis, and the results from subgroups of HCV‐infected patients with advanced fibrosis or cirrhosis are encouraging. Importantly, treatment with IFN slows progression of liver fibrosis, regardless of HCV genotype or early response to therapy, and reduces the risk of HCC by two‐ to fivefold. The risk of development of HCC is also lower in patients who show at least a partial response to IFN therapy compared with those who show no response. There is a clear need for more definitive studies of treatment in patients with chronic hepatitis C and cirrhosis, ideally using therapies with greater efficacy. Nonetheless, based on the potential to slow the progression of liver fibrosis (regardless of treatment response) and to reduce the risk of HCC, a greater number of HCV‐infected patients with cirrhosis should be considered as candidates for IFN treatment. Preliminary data indicate that pegylated IFNs have improved virological response rates and may have additional clinical benefits in the prevention or reduction of fibrosis and retardation of progression of cirrhosis and HCC in these patients.
Presence of TTV DNA in serum, liver and peripheral blood mononuclear cells from patients with chronic hepatitis
Authors: López‐Alcorocho J. M. , Mariscal L. F. , De Lucas S. , Rodríguez‐Iñigo E. , Casqueiro M. , Castillo I. , Bartolomé J. , Herrero M. , Manzano M. L. , Pardo M. , Carreño V.
Published: March 2003

The main site of TT virus (TTV) replication remains unknown. Therefore, we have studied the presence and titres of TTV DNA in paired serum, liver and PBMC samples from 50 patients with liver disease (32 with chronic hepatitis B or C, seven with cryptogenic hepatitis and 11 with nonviral liver disease) were included. TTV DNA was analysed by polymerase chain reaction (PCR) using primers from the open reading frame 1 (ORF 1) and from the untranslated region (UTR) and titres were semiquantified by PCR using an external standard. TTV DNA was detected in 26% of serum, 24% of liver and 14% of PBMC samples with ORF 1 primers. When UTR primers were used, 70% of serum and liver samples and 64% of PBMC were TTV DNA positive. No differences between TTV positive and negative patients were found regarding epidemiological or biochemical parameters. Trypsin treatment and fluorescent in situ hybridization confirm the intracellular location of TTV in PBMC. The mean of TTV DNA titres was statistically higher in liver than in serum or PBMC. TTV titres in serum correlated with those in PBMC but not with those in liver. In conclusion, although the liver seems to be the main site for TTV replication, this virus is also able to infect PBMC.
HCV RNA levels during therapy with amantadine in addition to interferon and ribavirin in chronic hepatitis C patients with previous nonresponse or response/relapse to interferon and ribavirin
Authors: Carlsson T. , Lindahl K. , Schvarcz R. , Wejstal R. , Uhnoo I. , Shev S. , Reichard O.
Published: March 2003

Interferon (IFN) alpha in combination with ribavirin (RIB) is standard therapy for patients with chronic hepatitis C virus (HCV) infection. However, many patients do not respond with sustained HCV clearance to this therapy. At present, no accepted treatment strategy exists for these patients. Recent preliminary data have suggested that amantadine (AMA) is effective against HCV infection. In a pilot study, we treated 13 nonresponders and 10 response/relapsers to previous IFN/RIB therapy with AMA 200 mg per day in combination with IFN 3 MU thrice weekly, and RIB 1000 mg per day for 24 weeks, with a 24‐week follow‐up period after end‐of‐treatment. At the end‐of‐treatment, 1 previous nonresponder and 5 previous response/relapsers were HCV RNA negative. At the end of follow‐up, only 1 previous response/relapser remained HCV RNA negative and had a sustained response. During therapy, serum HCV RNA became undetectable in 4 previous nonresponders, of whom 3 had a breakthrough at week 24. Twenty‐one patients continued therapy without dose reductions. One patient discontinued therapy prematurely due to sleeping disturbances, and another patient was withdrawn from therapy due to heavy alcohol intake. We conclude that the addition of AMA to IFN and RIB was well tolerated but had little, if any, impact on HCV RNA eradication in nonresponders or response/relapsers to previous IFN/RIB combination therapy.
Fluctuation of serum HCV‐RNA levels in untreated blood donors with chronic hepatitis C virus infection
Authors: Kuramoto I. K. , Moriya T. , Schoening V. , Holland P. V.
Published: March 2003

The hepatitis C virus (HCV)‐RNA levels were measured in 281 serum samples from 32 untreated volunteer blood donors prospectively collected over a period of 14–73 months. The HCV‐RNA levels were tested by the branched DNA signal amplification assay. The mean HCV‐RNA levels of each donor ranged from 4.92 log10–6.36 log10 gene equivalents/mL (25%, median, 75% percentile; 5.51, 5.79, 6.12 log10 gene equivalents/mL). The fluctuations of HCV‐RNA levels in individuals, represented by the ratio of the maximum value divided by the minimum value, ranged from a 1.7‐ to a 141‐fold change. Fluctuations with more than a 10‐fold change were observed in five subjects: 11‐, 15‐, 17‐, 96‐ and 141‐fold changes. Eleven subjects were followed for at least 5 years; all subjects had fluctuations of HCV‐RNA levels greater than 3‐fold during the observation period. No blood donor was observed whose HCV levels changed from a high‐level phase to a low‐level phase or from low to high. No subjects cleared HCV during follow‐up, although two had undetectable HCV‐RNA levels transiently. These findings reveal that changes in HCV‐RNA levels occur which are unrelated to treatment with interferon and ribavirin.
First phase viral kinetic parameters as predictors of treatment response and their influence on the second phase viral decline
Authors: Layden Jennifer E. , Layden Thomas J. , Reddy K. Rajender , Levy‐Drummer Rachel S , Poulakos Jennifer , Neumann Avidan U.
Published: March 2003

summary. It has recently been shown that upon initiation of interferon (IFN) treatment there is a biphasic decline in hepatitis C virus (HCV) RNA levels. In preliminary results, the rate of second phase viral decline has been shown to be an excellent predictor of treatment response. In this analysis, we determined whether the first phase viral kinetic parameters affected the rate of second phase viral decline. We also assessed whether first phase viral kinetic parameters could be used to predict treatment response within 24 h of initiating treatment. This study is a retrospective analysis of two completed studies from which detailed kinetic data were obtained in patients infected with genotype 1 HCV. In both studies, viral levels were measured frequently over the first 24 h, allowing the determination of IFNs effectiveness in blocking viral production and the viral load at the end of the first phase (v1). The second phase decline slope was calculated by log‐linear regression on measurements of serum HCV RNA during days 2, 7 and 14. In study one, sustained viral response (SVR) rates were obtained, allowing the determination of the first phase's predictive power for SVR. Logistic regression and fisher exact tests were used to analyse data. In study one, no patient achieved SVR without an IFN effectiveness greater than 98% and a V1 less than 250 000 copies/mL. When V1 and IFN effectiveness werecombined to predict SVR, a negative predictive value= 100%, positive predictive value=71% and accuracy of 95% was obtained after only 24 h of IFN treatment. Both studies illustrated strong correlations for both IFN effectiveness and V1 with the rate of 2nd phase slope (P < 0.001). V1 also correlated significantly with a calculation of infected cell loss (delta), which is a major determinant of the second phase viral decline. These results suggest that early viral kinetics may predict lack of response after only 24 h of treatment initiation and indicate a strong link between the degree of viral load reduction during the first phase, and the subsequent 2nd phase decline slope. This might be explained by a viral dynamics model assuming a jump‐start of the immune response when viral loads are reduced below a threshold, subsequently giving rise to a faster 2nd phase decline slope.
Did the Arabian Oryx live in Egypt during pharaonic times?
Authors: Manlius N.
Published: March 2003

Thanks to a colour reproduction faithfully completed by French explorer Frédéric Cailliaud in the early XIXth century, we are able to view a missing Theban painting dating from the reign of Amenophis II (under the New Empire). It depicts a hunting scene in the desert and an oryx whose morphology and, above all, whose coat colouration obviously match those of the Arabian Oryx. Consequently, we put forward the hypothesis of the possible presence of the Arabian Oryx in the Eastern Desert in Egypt during pharaonic times.
Morphology of the second‐ and third‐instar larvae of Dermatobia hominis by scanning electron microscopy
Authors: DE FILIPPIS THELMA , LEITE
Published: March 2003

Larvae of Dermatobia hominis 10–27 days old were collected from experimentally infected rats and their morphology was studied by scanning electron microscopy. The moult from the second to third instar occurs at 18 days, with emergence from the host at 30 days post‐infection. The second‐instar larvae bear on the pseudocephalon, antennae (coeloconic sensilla), and coeloconic and basicoconic sensilla on the maxillary sensory complex. The thoracic segments bear small backwardly‐directed spines anteriorly and ventral trichoid and campaniform sensilla. The first four abdominal segments have small and large backwardly‐directed spines that are absent on segments five and six. The seventh and eighth abdominal segments have medium‐sized forwardly‐directed spines. Abdominal segments are encircled by campaniform sensilla. The terminal end of the eighth abdominal segment bears the anus, prominent anal lobes and two spiracular openings on each spiracular plate. Spiracular plates show a radial sun ray pattern. The rear abdomen also bears an ecdysal aperture, several pores and eight coeloconic sensilla. Although there are slight morphological differences, the spines (predominantly flat and thorn‐like) and sensilla (campaniform and coeloconic) of the third‐instar larvae show a similar arrangement to that of second‐instar larvae. Thoracic trichoid sensilla are not seen in third‐instar larvae. A perispiracular gland aperture is situated above each posterior spiracular opening. These morphological features are compared with those of other cuterebrid larvae.
Host preferences of tsetse (Diptera: Glossinidae) based on bloodmeal identifications
Authors: CLAUSEN  , ADEYEMI  , BAUER  , BRELOEER  , SALCHOW  , STAAK
Published: March 2003

An enzyme‐linked immunosorbent assay (ELISA) was developed to identify the origin of vertebrate blood in the guts of 29 245 wild‐caught flies of eleven Glossina species from various ecological zones of Africa. Depending on the quality of the bloodmeal samples, 62.8% of the samples were identified and could be assigned to a host‐group (e.g. ruminant), family (e.g. Bovidae) or species (e.g. Bos spp.). A total of 13 145 samples (44.9%) was identifiable up to the species level. With a few exceptions, the present results are in agreement with earlier published reports. Glossina austeni and G. fuscipleuris seemed to have a distinct feeding preference for Suidae (mainly bushpig). Glossina morsitans ssp. fed mainly on Suidae (mainly warthog), although local variations were observed and in some areas hippopotamus or ruminants replaced the warthog as the main host. Bushbuck seemed to be the principal food source for G. longipalpis and G. fusca. Glossina pallidipes fed mainly on ruminants (buffalo, bushbuck and cattle) but, depending on host availability and location, Suidae were also important hosts. Hippopotamus was identified as the main source of blood‐meals for G. brevipalpis. The main hosts for G. longipennis were Suidae (mainly bushpig) and not rhinoceros as had been reported 40 years earlier. The opportunistic feeding behaviour of the palpalis tsetse group was confirmed. The results showed that changes in environment, fauna and host availability may result in modification of tsetse feeding patterns.
Distribution of the Simulium damnosum complex on Bioko island, Equatorial Guinea, and the potential for onchocerciasis elimination by vector eradication
Authors: McCALL  , CHEKE  , WILSON,  , POST  , FLOOK  , MANK  , SIMA  , MAS
Published: March 2003

Onchocerciasis is endemic on the island of Bioko, Equatorial Guinea, where it is transmitted by the ‘Bioko form’ of the Simulium damnosum complex, a cytospecies unique to the island. To determine the distribution of vector breeding, three dry season and two wet season expeditions were made in 1989, 1996 and 1997, and 226 of the island's 247 rivers (91.5%) were visited. Of these 226 rivers, 130 (58%) were flowing during the dry season, forty‐five (20%) supported aquatic stages of Simuliidae of any species and twenty‐five (11%) contained larvae or pupae of the S. damnosum complex. The twenty‐one rivers not prospected were in the mountainous south of the island, where an additional seventeen rivers were reached but not satisfactorily prospected. Of these thirty‐eight rivers, twenty‐nine were considered highly likely to support vector breeding, bringing the total number of rivers which could harbour the vector during the dry season to fifty‐four (21.9% of the island's total). Breeding was believed to be limited to river stretches below 1000 m altitude, and during the dry season the total length of those stretches which could support breeding on Bioko was estimated to be 1020 km. A combination of factors, including low river discharges during the dry season, the relatively low water temperature on Bioko, the suitability of limited stretches of most rivers as vector breeding sites and the close proximity of many rivers within a small geographical area, render the vector vulnerable to eradication by aerial treatment of rivers with insecticide. The isolation of the Bioko form of the S. damnosum complex suggests that reinvasion following treatment would be unlikely, and eradication of the vector might be achieved by a dry season larviciding programme in one or two years.
Thanaka (Limonia acidissima) and deet (di‐methyl benzamide) mixture as a mosquito repellent for use by Karen women
Authors: LINDSAY  , EWALD  , SAMUNG  , APIWATHNASORN  , NOSTEN
Published: March 2003

The prevention and treatment of drug‐resistant malaria is becoming increasingly difficult. On the Thai–Myanmar border multi‐drug resistant strains of falciparum malaria are increasing and, because the malaria vector Anopheles bite outdoors during early evening, insecticide house‐spraying or impregnated bednets provide only limited protection. Therefore, the protective efficacy of repellent formulations containing di‐methyl benzamide (deet) and permethrin against local vectors was estimated, when applied to the skin, and their acceptability amongst pregnant Karen women who are at relatively high risk from malaria was assessed. Human landing catches of mosquitoes showed that almost complete protection was achieved using different formulations of 20% deet and 0.5% permethrin for up to 6 h. All‐night collections from human subjects indicated that this repellent combination reduced exposure to malaria parasites by at least 65 and 85% for those transmitted by Anopheles minimus and An. maculatus, respectively, the two principal vectors in this area. Pregnant women in the camps preferred repellents which were mixed with ‘thanaka’, a root paste made from pulp of the wood apple tree, Limonia acidissima, used locally as a cosmetic. Apart from a temporary warming sensation where repellent thanaka was applied to the skin, the repellents were well tolerated. An intervention trial is currently in progress to determine whether deet mixed with thanaka can protect pregnant women against malaria in this part of the world. Bioassays using a laboratory strain of Aedes aegypti demonstrated that thanaka is itself slightly repellent at high dosages and the mixture with deet provides protection for over 10 h. This treatment would therefore also provide some personal protection against dengue, which is increasing locally, transmitted by Ae. aegypti and Ae. albopictus biting during the daytime.
Determination of dengue virus serotypes in individual Aedes aegypti mosquitoes in Colombia
Authors: ROMERO‐VIVAS  , LEAKE  , FALCONAR
Published: March 2003

Adult Aedes aegypti mosquitoes were collected in Puerto Triunfo, central Colombia, where dengue is endemic, during a six month period. Viral infection within the head of each individual mosquito was identified by an immunofluorescent assay (IFA) using a flavivirus‐specific monoclonal antibody. The dengue virus serotype, present in each flavivirus‐positive specimen, was then determined in portions of the remaining thorax using IFAs with serotype‐specific monoclonal antibodies. Among 2065 female Aedes aegypti collected and tested, twenty‐four flavivirus‐positive individuals were found (minimum infection rate 11.6%), three identified as dengue type‐1 and twenty‐one as dengue type‐2 virus. This was consistent with the isolation of only these two serotypes of dengue virus from dengue fever patients within this town. No vertical transmission of dengue virus could be detected in 1552 male Aedes aegypti collected. This method is inexpensive, simple, rapid to perform and suitable for use in developing countries to identify and distinguish different serotypes of dengue virus in their vectors during eco‐epidemiological investigations.
Factors affecting numbers ofCulicoidesin truck traps in coastal Queensland
Authors: Kettle D. S. , Edwards Penelope B. , Barnes A.
Published: March 2003

Abstract.Truck trap collections of Ceratopogonidae were made over a period of 27 months (November 1973–February 1976) at Tingalpa Creek, in southeast Queensland, Australia. Six collections were made on each of 95 days, giving 570 observations and a total of 29 378 Culicoides. Two collections were made before, one at, and three after sunset. Separate analyses were made of the catches of thirteen entities: male and female C. austropalpalis, C. brevitarsis, C. marksi, C. marmoratus and C. victoriae, female C. henryi and C. longior, and total C. bundyensis.

Catches were dominated by C. brevitarsis (35.2%) and C. marmoratus (32.3%) and, with C. victoriae, were taken on almost every collecting day over all seasons. Sex ratios (M:F) varied from 0:100 for C. longior to 130:100 for C. marksi. Collections of all entities, except female C. henryi, were greatest (50–70% of the daily catch) at sunset. In winter there was substantial activity in the hour before sunset. Time of day was the most important variable, accounting for 15–45% of the observed variation. Between‐day differences were significant for all except C. austropalpalis, C. victoriae and male C. marksi. Culicoides brevitarsis, C. bundyensis and C. longior had highly significant annual cycles, C. victoriae and female C. austropalpalis had significant lunar cycles, and C. longior had a significant tidal cycle. Logarithms of catches of female C. austropalpalis, C. brevitarsis, C. henryi, C. marmoratus, and female and male C. victoriae were inversely related to linear wind speed. Log catches of female C. austropalpalis, C. brevitarsis, C. marmoratus and C. victoriae, and male C. marksi and C. victoriae were positively related to temperature (quadratic).
Selection of susceptible and refractory lines ofGlossina morsitans centralisforTrypanosoma congolenseinfection and their susceptibility to different pathogenicTrypanosomaspecies
Authors: Moloo S. K. , Kabata J. M. , Waweru F. , Gooding R. H.
Published: March 2003

Abstract.In a single generation of selection, two lines of Glossina morsitans centralis were established that differed significantly in susceptibility to Trypanosoma congolense clone IL 1180. Reciprocal crosses demonstrated that susceptibility was a maternally inherited trait. Differences between the lines, to all phases of the trypanosome infection, were maintained for eight generations, whereas differences in susceptibility to midgut infections were maintained for twenty‐eight generations. Thereafter, the lines did not differ in susceptibility to Trypanosoma congolense IL 1180. Susceptibility to infections with Trypanosoma congolense IL 1180 was only a weak predictor of susceptibility to T. congolense clones IL 13‐E3 and K60/1, as well as clone T. brucei brucei STIB 247‐L. However, the susceptible and refractory lines displayed these phenotypes when tested with Trypanosoma vivax, indicating that the factors that affect susceptibility to trypanosomes are expressed both within and outside the midgut.
Failure of Hydrotaea aenescens, a larval predator of the housefly, Musca domestica, to establish in wet poultry manure on a commercial farm in Florida, U.S.A.
Authors: Hogsette J. A. , Jacobs R. D.
Published: March 2003

Hydrotaea aenescens (Weidemann) (Diptera: Muscidae) larvae and pupae were released in high‐rise pullet houses in Pascoe County, Florida, U.S.A., for biological control of houseflies, Musca domestica L. (Diptera: Muscidae), in three separate tests during a 14‐month period (April 1994–May 1995) and did not become established. However, H. aenescens believed to be from our releases did become established at a caged‐layer farm 0.3 km from the release farm. Moisture in pullet house manure generally exceeded 80%, which is above the level at which H. aenescens is reared in colony. Caged‐layer manure was also very wet, but crusted areas provided sites for H. aenescens larval development. Results demonstrate that H. aenescens adults will disperse from release sites and populate preferred sites without becoming a nuisance.
Estimation of the effects of buffalo fly (Haematobia irritans exigua) on the milk production of dairy cattle based on a meta‐analysis of literature data
Authors: Jonsson N. N. , Mayer D. G.
Published: March 2003

Published reports on the effect of buffalo flyHaematobia irritans exiguaDe Meijere (Diptera: Muscidae) and the closely related horn fly (H. irritans) were examined and analysed using non‐linear weighted regression techniques in an attempt to establish the relationship between daily production loss (D), average number of parasites (n) and the average damage per parasite per day (d), and to provide estimates of expected losses in milk yield (MYD) and live‐weight gain (LWG) in dairy cattle. A Mitscherlich three‐parameter model was used to explain the relationship between the total loss of production attributable to buffalo flies and the average number of flies associated with cattle. This model was significant (P< 0.01), withR2 = 20.2% and predicted a threshold number of flies (n = 30) below which no adverse effects would be noted. At a moderate level of infestation (n = 200)dMYDwas 2.6 ml/fly/day anddLWGwas 0.14 g/fly/day, resulting in estimated daily losses in milk yield (DMYD) and live‐weight gain (DLWG) of 520 ml and 28 g, respectively.
Courtship and mating by the sandfly Phlebotomus duboscqi, a vector of zoonotic cutaneous leishmaniasis in the Afrotropical region
Authors: Valenta D. T. , Killick‐Kendrick R. , Killick‐Kendrick M.
Published: March 2003

Courtship behaviour of males of the Afrotropical sandfly Phlebotomus duboscqi Neveu‐Lemaire (Diptera: Psychodidae) involved mounting the female and clasping her ‘waist' with the male coxites placed between the female's thorax and abdomen. This behaviour, which we call ‘piggy‐backing', was preceded by male wing beating, perhaps involving mate recognition and contact pheromones. It did not seem to be pre‐ or postcopulatory mate guarding. Piggy‐backing was attempted by P. duboscqi males on females of other species (P. papatasi and P. perniciosus) and even on other male P. duboscqi. The majority of female P. duboscqi piggy‐backed by males were already inseminated, and most of the courting did not lead to copulation. This, coupled with the presence of a mating plug (semen) in each spermatheca of inseminated females, suggests that female P. duboscqi are monogamous for at least the first gonotrophic cycle. Male courtship with piggy‐backing was more intense when females could feed on a hamster than when a hamster was present but the females were denied access to the host. It is suggested that, when a hamster was available to the females, the conditions in the laboratory are similar to those in rodent holes, the natural habitat of P. duboscqi.
Role of small mammals in the persistence of Louping‐ill virus: field survey and tick co‐feeding studies
Authors: Gilbert L. , Jones L. D. , Hudson P. J. , Gould E. A. , Reid H. W.
Published: March 2003

Louping‐ill (LI) is a tick‐borne viral disease of red grouse,Lagopus lagopus scoticusLath. (Tetraonidae: Galliformes), and sheep,Ovis ariesL. (Bovidae: Artiodactyla), that causes economic loss to upland farms and sporting estates. Unvaccinated sheep, grouse and mountain hares,Lepus timidusL. (Leporidae: Lagomorpha), are known to transmit LI virus, whereas red deer,Cervus elaphusL. (Cervidae: Artiodactyla),and rabbits,Oryctolagus cuniculusL. (Leporidae: Lagomorpha),do not. However, the role of small mammals is unknown. Here, we determine the role of small mammals, in particular field voles,Microtus agrestisL. (Muridae: Rodentia), in the persistence of LI virus on upland farms and sporting estates in Scotland, using field sampling and non‐viraemic transmission trials. Small mammals were not abundant on the upland sites studied, few ticks were found per animal and none of the caught animals tested sero‐positive to LI virus. Laboratory trials provided no evidence that small mammals (field voles, bank voles,Clethrionomys glareolusL. (Muridae: Rodentia), and wood mice,Apodemus sylvaticusL. (Muridae: Rodentia), can transmit LI virus between cofeeding ticks and, in the field, LI virus was prevalent only in areas with known LI virus competent hosts (grouse, mountain hares or unvaccinated sheep) and absent elsewhere. In contrast to the case of tick‐borne encephalitis (TBE) virus in Europe, it is concluded that small mammals seem to be relatively unimportant in LI virus persistence.
Sampling methods for phlebotomine sandflies
Authors: Alexander B.
Published: March 2003

A review is presented of methods for sampling phlebotomine sandflies (Diptera: Psychodidae). Among ∼500 species of Phlebotominae so far described, mostly in the New World genusLutzomyiaand the Old World genusPhlebotomus, about 10% are known vectors ofLeishmaniaparasites or other pathogens. Despite being small and fragile, sandflies have a wide geographical range with species occupying a considerable diversity of ecotopes and habitats, from deserts to humid forests, so that suitable methods for collecting them are influenced by environmental conditions where they are sought. Because immature phlebotomines occupy obscure terrestrial habitats, it is difficult to find their breeding sites. Therefore, most trapping methods and sampling procedures focus on sandfly adults, whether resting or active. The diurnal resting sites of adult sandflies include tree holes, buttress roots, rock crevices, houses, animal shelters and burrows, from which they may be aspirated directly or trapped after being disturbed. Sandflies can be collected during their periods of activity by interception traps, or by using attractants such as bait animals, CO2or light. The method of trapping used should: (a) be suited to the habitat and area to be surveyed, (b) take into account the segment of the sandfly population to be sampled (species, sex and reproduction condition) and (c) yield specimens of appropriate condition for the study objectives (e.g. identification of species present, population genetics or vector implication). Methods for preservation and transportation of sandflies to the laboratory also depend on the objectives of a particular study and are described accordingly.
African horse sickness epidemiology: vector competence of South African Culicoides species for virus serotypes 3, 5 and 8
Authors: Venter G. J. , Graham S. D. , Hamblin C.
Published: March 2003

The oral susceptibilities of 17 Culicoides species to infection with African horse sickness virus (AHSV) serotypes 3, 5 and 8 were determined by feeding field‐collected midges on AHSV infected horse blood. The mean titres of virus in the bloodmeals for the three serotypes of AHSV were between 5.7 and 6.5 log10TCID50/ml. Virus was detected, after 10 days incubation at 23.5°C, in the Culicoides imicola Kieffer (Diptera: Ceratopogonidae) that had fed on blood containing AHSV 5 (8.5%) and 8 (26.8%), and in the Culicoides bolitinos Meiswinkel that had fed on AHSV 3 (3.8%), 5 (20.6%) and 8 (1.7%). Although 44.4% of the C. imicola were shown to have ingested AHSV 3 immediately after feeding, no virus was detected in 96 C. imicola after incubation. The relatively high titres of virus recorded in individual midges of both species after 10 days incubation suggested a fully disseminated infection. Previously, C. imicola was considered to be the only field vector of AHSV in Africa. Identifying C. bolitinos as a potential vector for AHSV is an important finding, which if proven will have a significant impact on our understanding of the epidemiology of AHS. No AHSVs could be detected in the other 15 species of Culicoides assayed, which suggests that some of the southern African Culicoides species are refractory to AHSV infection. However, further work with larger numbers of each species will be necessary to confirm this observation.
Comparison of three pyrethroid treatments of top‐sheets for malaria control in emergencies: entomological and user acceptance studies in an Afghan refugee camp in Pakistan
Authors: Graham K. , Mohammad Nasir , Rehman Hamid , Farhan Mushtaq , Kamal Mohammed , Rowland M.
Published: March 2003

Abstract Insecticide‐treated bedding materials (sheets and blankets) could be protective against vectors of malaria and leishmaniasis − especially in complex emergencies, epidemics and natural disasters where people are more likely to sleep in exposed situations. Comparison of cotton top‐sheets impregnated with different pyrethroids (permethrin 500 mg/m2, deltamethrin 25 mg/m2 or alphacypermethrin 25 mg/m2) for effectiveness against mosquitoes (Diptera: Culicidae) was undertaken in a refugee camp in Pakistan. Predominant species encountered were Anopheles stephensi Liston, An. pulcherrimus Theobald, An. nigerrimus Giles, Culex quinquefasciatus Say, Cx. tritaeniorhynchus Giles and other culicine mosquitoes. All three pyrethroid treatments performed significantly better than the untreated sheets in deterrence and killing of mosquitoes. No significant differences were found between the three insecticides tested in terms of entomological effect. Washing of the treated sheets greatly reduced their effectiveness. In a user acceptance study conducted among 88 families (divided into four groups), six families complained of irritation of the skin and mucous membranes. Of these reports, one was from the placebo group (using untreated sheets) and the other five (5/22 = 23%) from families using deltamethrin‐treated sheets. All families allocated to permethrin and alphacypermethrin groups declared an appreciation for the intervention and reported no side‐effects. Ten of the placebo group disliked the intervention, citing no prevention of mosquito biting as the reason. Side‐effects associated with deltamethrin indicate that alphacypermethrin and permethrin are more appropriate first choice insecticides for treatment of sheets and blankets.
A comparison of the vector competence of the biting midges, Culicoides (Avaritia) bolitinos and C. (A.) imicola, for the Bryanston serotype of equine encephalosis virus
Authors: Venter G. J. , Groenewald D. , Venter E. , Hermanides K. G. , Howell P. G.
Published: March 2003

Abstract Equine encephalosis virus (EEV) is widespread and prevalent in southern Africa. In this study, the oral susceptibility of Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae) to EEV was confirmed. In addition, C. (A.) bolitinos Meiswinkel, collected in the high‐lying eastern Free State, South Africa, was systemically infected with the Bryanston serotype of EEV after feeding through a membrane on artificially infected equine blood containing 4.7 log10 PFU/mL of EEV. The mean infectivity of Bryanston virus in C. bolitinos increased from 1.2 log10 PFU/midge, in midges assayed for virus immediately after feeding on the blood‐virus mixture, to 3.1 log10 PFU/midge in midges assayed after 10 days' incubation at 23.5°C. Elevated virus infectivity titres, found in individual infected C. bolitinos, suggested that this Culicoides species is a vector of EEV. This bovine dung‐breeding Culicoides species may play an important role in transmitting EEV in the cooler parts of southern Africa, where it can be the most abundant Culicoides species collected near livestock. In the present study the prevalence of infection obtained for C. bolitinos (2.2%) with the Bryanston serotype of EEV was significantly lower than that of C. imicola (18.4%). After incubation, the Bryanston serotype of EEV was also isolated from one of 110 C. onderstepoortensis Fiedler assayed. However, the virus titre in this midge was 1.2 log10 PFU/midge, which is not different from the titre that would be expected immediately after feeding on the blood‐virus mixture. Culicoides species that survived the incubation period and that were negative for the presence of Bryanston virus were C. magnus Colaço (96), C. bedfordi Ingram & Macfie (95) and C. pycnostictus Ingram & Macfie (45).