Environmental factors associated with Dictyocaulus viviparus and Fasciola hepatica prevalence in dairy herds from Costa Rica.

Dictyocaulosis and fasciolosis are parasitic diseases that cause considerable economic losses for owners of farm animals worldwide, with special relevance on fasciolosis because it is an emerging zoonosis. Indirect diagnosis of these diseases through analyses of bulk milk tank samples has allowed carrying out large-scale prevalence studies, while the use of geographical information systems has helped to visualize and determine those variables that affect distribution of these pathogens. This study is intended to describe the spatial distribution of Dictyocaulus viviparus and Fasciola hepatica in dairy herds from Costa Rica, as well as their associated environmental factors. Bulk milk tank samples from 526 dairy herds in the three most important dairy regions of Costa Rica were analyzed using enzyme immunoassays. Results from the farms were subjected to spatial analyses using Holdridge's life zones, relief and soil type environmental layers. Of the total bulk milk tank samples analyzed, 3.8% (n=20) and 3.6% (n=19) were positive for D. viviparus and F. hepatica, respectively. Moran's I analysis revealed the existence of potential cluster (Moran's I=1.789, z=12.726 p<0.05) for D. viviparus. Consequently, Getis-Ord General G analysis showed that the spatial distribution of positive farms in the dataset was clustered (Observed General G=0.015, variance=0.000001, z=12.823, p<0.05). No significant positive spatial autocorrelation (Moran's I=0.038, z=0.286, p>0.0.5) was observed for F. hepatica. Furthermore, a significant difference was detected in the spatial locations of both parasites (latitude p<0.05, longitude p<0.05), and about the spatial distribution of both D. viviparus negative and positive farms (latitude p<0.05, longitude p<0.05), as well as in F. hepatica negative and positive farms regarding on latitude (p<0.05), but not on longitude (p>0.05). In the case of environmental factors, significant differences were found for D. viviparus and F. hepatica with respect to types of soil, precipitation, altitudinal belts, life zones, biotemperature, and elevation.

Genes of the bovine lungworm Dictyocaulus viviparus associated with transition from pasture to parasitism.

Genes necessary to enable nematode parasitic life after free-living larval life are of substantial interest to understand parasitism. We investigated transcriptional changes during transition to parasitism in the bovine lungworm Dictyocaulus viviparus, one of the most important parasites in cattle farming due to substantial economic losses. Upregulated transcripts in either free-living, developmentally arrested L3 or parasitic immature L5 were identified by suppression subtractive hybridization (SSH) followed by differential screening and subsequent virtual Northern blot verification. From 400 sequenced clones of parasitic L5, 372 (93.0%) upregulated high quality ESTs were obtained clustering into 30 contigs and 38 singletons. Most conceptual translated peptides were SCP/TAPS "family" members also known as pathogenesis-related protein (PRP) superfamily (28.5% of total ESTs), cysteine proteases (24.5%), and H-gal-GP orthologues (9.9%). These proteins are predicted to play key roles in fundamental biological processes such as nutrition and development but also parasite-host interactions and immune defense mechanisms. Increased energy requirement of the rapidly developing L5 lungworm stage was obvious in a proportion of 12.2% upregulated ESTs being components of the respiratory chain. From the developmentally arrested L3 stage sequencing of 200 clones resulted in 195 high quality ESTs (97.0%) clustering into 7 contigs and 3 singletons only. Besides a hypothetical protein (70.1% of total ESTs) most transcripts encoded the cleavage stimulation factor subunit 2 (17.5%), which is a component of the poly(A(+)) machinery and found to be involved in gene silencing. Obtained data provide the basis for future fundamental research into genes associated with parasitic lifestyle but also applied research like vaccine and/or drug development.

Prevalence of endoparasites in stray and fostered dogs and cats in Northern Germany.

To get an overview of the current state of endoparasite prevalences in stray and not well-cared dogs and cats, faecal samples of 445 stray and foster dogs and 837 stray and foster cats were collected at their arrival at animal shelters in Lower Saxony (Germany). They were investigated for infections with endoparasites by the use of sedimentation-flotation method. Additionally, 341 canine and 584 feline samples were investigated by IDEXX SNAP® Giardia test. Stages of endoparasites were found coproscopically in 9.4 % (n = 42) of the canine samples, 4.0 % were positive for Toxocara canis, 0.9 % for hookworms, 0.4 % for Toxascaris leonina and 0.2 % for Hammondia-like oocysts. Giardia-coproantigen was detected in 11.4 % of the canine samples. In cats, 33.6 % (n = 281) were coproscopically positive for helminths and/or protozoa. Toxocara cati was found in 27.1 %, Isospora spp. in 7.5 %, Capillaria spp. 5.0 %, Taeniidae in 2.0 %, hookworms in 1.1 %, Giardia sp. in 0.7 %, Aelurostrongylus abstrusus in 1.0 % and Toxoplasma-like oocysts in 0.1 %. Coproantigen specific for Giardia sp. was detected in 6.8 % of the feline samples. Dogs and cats up to 1 year of age were more frequently infected with endoparasites than animals over 1 year of age (p < 0.001). Toxocara spp. and Isospora spp. were detected significantly more often in younger dogs and cats, respectively (p < 0.05 and p < 0.001). Stray dogs or cats older than 1 year were significantly more frequently infected with endoparasites than dropped off animals of the same age group (p < 0.05). Using the faecal egg count reduction test, the therapeutic efficacy of some anthelmintics was tested. All tested anthelmintics showed high efficacy and no suspected anthelmintic resistance was found. However, endoparasite-infected stray and free-roaming cats and dogs may contribute considerably to the contamination of public parks, playgrounds and sandpits with zoonotic parasites and therefore have to be considered a public health problem.

Occurrence of Bartonella henselae and Borrelia burgdorferi sensu lato co-infections in ticks collected from humans in Germany.

Bartonella (B.) henselae is the zoonotic agent of cat scratch disease. B. henselae has been associated with therapy-resistant Lyme disease in humans suggesting that B. henselae and Borrelia burgdorferi sensu lato might be transmitted concurrently by ticks. In the present study we found that 16 (6.9%) of 230 Ixodes ricinus collected from humans harboured DNA of Bartonella spp. Fifteen positive ticks were infected with B. henselae and one tick with B. clarridgeiae. Twenty-five percent of the 16 Bartonella positive ticks were co-infected with Borrelia burgdorferi sensu lato. Our data show that B. henselae is present in Ixodes ricinus and that ticks may serve as source of infection for humans.

A cross-sectional survey of gastrointestinal parasites with dispersal stages in feces from Costa Rican dairy calves.

A cross-sectional study was carried out to determine the prevalence of gastrointestinal parasites and lungworm nematodes in dairy calves from five different ecoclimatic areas of Costa Rica. Also intensity of infection of nematodes was determined. In order to describe management practices and anthelmintic control, a questionnaire was applied in 73 farms. The influence of area, farm, host (breed, age) and ecological factors (low and high rainfall period) upon eggs per gram feces (epg) of gastrointestinal nematodes (GIN) and first larval stage counts (L1) of Dictyocaulus viviparus were investigated. Furthermore, association of host, ecological and management risk factors to the prevalence of gastrointestinal parasites and D. viviparus were analyzed. The most prevalent GIN, cestodes and protozoan identified in dairy farms were similar in all areas studied. Strongylidae was the most prevalent parasite group detected, represented mainly by Haemonchus spp. and Cooperia spp., whereas Ostertagia spp. and Mecistocirrus digitatus were barely found. The most prevalent protozoan was Eimeria spp. The questionnaire applied to producers revealed the following management practices: weaning age of calves 1-4 months (52.1%), semi-confinement of calves upon 5-8 months of age (41.1%), number of paddocks used for calves <10 (57.5%), first deworming of calves at ages ≥15 days (74.70%) and deworming of calves at intervals >60 days (52.1%). Anthelmintic products were changed in 56.1% of the farms at intervals between 13 and 24 months. Although 91.8% of the farms had veterinary assistance, the majority performed parasite control regimes according to the criteria of the producers (66.7%). Common practices were the dispersion of animal feces on the pastures (64.4%) and use of disinfectant in the milking room (63.4%). The analyses of variance showed significant influence (p<0.05) of age, rainfall period, interaction of rainfall period on area (rainfall period×area) and nested effect of farm within area [farm (area)] on epg of Strongylidae; age, area, rainfall period×area and [farm (area)] on epg of Strongyloides papillosus; age, rainfall period and farm (area) on epg of Trichuris spp.; rainfall period, rainfall period×area and [farm (area)] on L1 of D. viviparus. The logistic regression analyses determined area, semi-confinement, management of feces, use of disinfectant in the milking room as risk factors for the presence of Strongylidae, S. papillosus and Trichuris spp; rainfall, age, paddock numbers for D. viviparus; and area, age, veterinary assistance, deworming program, age at first deworming and use of disinfectant in the milking room for Eimeria spp. and Buxtonella sulcata.

Giardia in symptomatic dogs and cats in Europe--results of a European study.

The percentage of Giardia infection in dogs and cats with gastrointestinal signs presenting to clinics was examined across Europe using the IDEXX SNAP Giardia Test (IDEXX Laboratories). Veterinary practices were asked to identify diarrheic and/or vomiting dogs and cats and to use the test on fecal samples from these animals. A selection for "asymptomatic" testing was also available on the data collection sheet for testing that occurred outside the target "symptomatic" population. Results from 8685 dogs and 4214 cats were submitted during the sampling period from 2005 to 2006. Analysis of the data showed 24.78% of the samples positive for Giardia among tested dogs and 20.3% among tested cats. The younger the dog or the cat, the higher the risk of being positive, peaking in the category below 6 months. The main clinical symptom, diarrhoea, also showed a higher risk of being positive, OR's of acute diarrhoea were almost double of those of the category "asymptomatic" for dogs or cats, the same range was calculated for chronic diarrhoea. Differences in participating countries were also seen. The risk of being positive was half or less in UK, Spain, Netherlands, Italy compared to Germany, and only in Belgium it showed to be higher. The results of this study show that Giardia is a common enteric agent among dogs and cats with gastrointestinal signs in Europe.

Endoparasite control management on horse farms--lessons from worm prevalence and questionnaire data.

REASONS FOR PERFORMING STUDY: Increasing prevalence of anthelmintic resistance in equine nematodes calls for a reexamination of current parasite control programmes to identify factors influencing control efficacy and development of resistance. OBJECTIVES: To investigate if associations occur between prevalence of parasitic nematodes and management practices. METHODS: German horse farms (n = 76) were investigated in 2003 and 2004. Information on farm and pasture management with respect to endoparasite control measures obtained using a questionnaire survey. Faecal examinations were performed in parallel. RESULTS: Horses (n = 2000) were examined by faecal nematode egg counts, grouped into foals, yearlings and mature individuals for statistical analyses. Farms were categorised into 3 types, riding, stud farms and small holdings. Count regression models were used to analyse strongyle faecal egg count data. Following dichotomisation of faecal egg count (FEC) data, prevalence of strongyle and Parascaris equorum infections were assessed by logistic regression models as a function from various management factors. Yearlings on stud farms showed a 2-fold higher risk of being positive for strongyle FEC, higher (i.e. > or =3 per year) anthelmintic drug treatment frequencies were associated with reduced strongyle infection rates only in mature individuals but not in foals or yearlings, foals on farms fertilising pastures with horse manure had a significantly higher risk of being P. equorum FEC positive and yearlings on stud farms were more often showing incomplete FECR following anthelmintic treatment compared to yearlings on other farm types. The mean yearly treatment frequencies per age group were: foals 4.52, yearlings 3.26 and mature horses 2.72 times, respectively. CONCLUSION AND POTENTIAL RELEVANCE: To delay the development of anthelmintic, resistance management should include additional nonchemotherapeutic parasite control strategies, FEC-monitoring, controlled quarantine treatment of new arrivals and control of efficacy by the faecal egg count reduction test on a regular basis.

The use of bulk-tank milk ELISAs to assess the spatial distribution of Fasciola hepatica, Ostertagia ostertagi and Dictyocaulus viviparus in dairy cattle in Flanders (Belgium).

Fasciola hepatica, Ostertagia ostertagi and Dictyocaulus viviparus are helminth parasites with a wide distribution and an important economic impact in cattle in temperate climates. This paper describes the spatial distribution of F. hepatica, O. ostertagi and D. viviparus in dairy herds in Flanders (Belgium). One thousand eight hundred herds were selected at random from the Flemish dairy population (n=7002), stratified on community level to obtain a sample representative for the entire study area. From each herd, a bulk milk sample collected in autumn 2006 was analysed with previously described antibody-ELISAs in order to identify herds where the parasite infection level is likely to cause production loss (F. hepatica and O. ostertagi) (defined as economic infections) or where patent infections have been present over the past grazing season (D. viviparus). The herd prevalence of economic infections with F. hepatica and O. ostertagi was 37.3% (95% Confidence Interval (CI): 35.1-39.7) and 59.1% (95%CI: 56.8-61.4), respectively. The herd prevalence of D. viviparus was 19.6% (95%CI: 17.7-21.6). On 28.9% (CI 26.8-31.3) of the herds, low levels of infection were observed for all three of the helminths. The presence of clustering of (economic) infections was studied using Moran's I, whereas the location and size of the clusters were studied using the spatial scan statistic, the Local Indicator of Spatial Association and Kernel density plotting. A marked clustering in the spatial distribution of F. hepatica and a mild clustering in the spatial distribution of O. ostertagi were observed. D. viviparus infections were spread evenly over Flanders. Knowledge of locations of high risk areas can lead to increased awareness and may be the start of the development of regionally adapted control measures.

Stage-dependent transcriptional changes and characterization of paramyosin of the bovine lungworm Dictyocaulus viviparus.

The bovine lungworm Dictyocaulus viviparus is of major economic importance in cattle farming in the temperate zones. The invertebrate protein paramyosin is one of the main components of muscle thick filaments but can also exhibit immunomodulatory functions. It represents a promising vaccine candidate in parasitic helminths. In this study, D. viviparus paramyosin (DvPmy) was characterized on the transcriptional as well as genomic level. The identified genomic sequence comprises 19 introns compared to only 10 introns in the Caenorhabditis elegans orthologue. Quantitative real time PCR transcriptional analysis revealed paramyosin transcription throughout the whole parasite's life cycle with the highest transcription rate in the agile moving first-stage larvae and the lowest in motionless hypobiosis induced third stage larvae. Recombinantly expressed DvPmy was found to bind collagen and IgG. Thereby the present study is the first showing that nematode paramyosin has the capability for immunomodulation and thus may be involved in host immune defence.

Experiences with Duddingtonia flagrans administration to parasitized small ruminants.

The aim of this study was to investigate the effect of the nematophagous fungus Duddingtonia flagrans applied orally to small ruminants in a field study in Germany. 20 female, pure breed goat kids and 20 female, pure breed lambs, all naturally infected with GIN, were kept on pasture and fed additionally with concentrates amended by 5 x 10(5) spores of D. flagrans per kilogram bodyweight daily for 3 months during pasture season. The equally sized control groups got the concentrate without spores. Every fortnight data of body weight, eggs per gram faeces and larval development in faecal cultures and on pasture were collected. Following 3 months of spore feeding the control goats showed arithmetic mean faecal egg counts of 1235 (+/-533) eggs per gram (epg) faeces, in comparison to 517 (+/-671) epg in the fungus-fed group (p<0.001). No statistically significant difference was found between the two sheep groups. The maximum in larval reduction in faeces was found at the end of the fungus-feeding period (81.3% in the sheep groups and to 67.9% in the goat groups), but without statistical significance. At the end of the study the mean body weight gain in the fungus-treated groups tended to be higher than in the control groups, but not showing statistically significant differences. Only regarding the first-year-grazing-goats, the bodyweights of the post-feeding period revealed significant (p<0.05) differences between fungus-fed and control group. However, no statistically significant differences were observed in qualitative faecal cultures, pasture larvae counts, serum pepsinogen-level and PCV. In the study presented here, no clear effect of fungus could be observed. Furthermore, climatic conditions during the study period may have demonstrated how vulnerable the fungus application is to such parameters.

Comparative efficacy of imidacloprid, selamectin, fipronil-(S)-methoprene, and metaflumizone against cats experimentally infested with Ctenocephalides felis.

Four active ingredients--imidacloprid selamectin, fipronil-(S)-methoprene, and metaflumizone--were tested to assess the speed of flea kill against existing flea infestations and subsequent reinfestations. Thirty flea-infested cats were allocated to four treatment groups and one untreated control group. Flea counts were performed 6, 18, and 48 hours after treatment (day 0) and 2, 4, and 24 hours after weekly flea reinfestations. Cats were also reinfested with fleas after the 6- and 18-hour counts on day 0 and after the 2- and 4-hour counts on subsequent count days. Imidacloprid provided significantly greater flea kill at diverse time points. At the 24-hour counts, all compounds showed expected and similar high efficacies. On study day 34, imidacloprid showed the highest efficacy at 24 hours after reinfestation, with 90.8% flea reduction compared with 55.7% to 67.4% in the other treatment groups. A single topical application of imidacloprid provided a high efficacy in the early elimination of adult fleas, limiting the risk of pathogen transmission and flea allergy dermatitis.

Monitoring of basophil sensitization to antigens of the cat flea (Ctenocephalides felis felis): a new tool for the diagnosis of feline flea bite hypersensitivity?

Suitability of blood basophils for in vitro diagnosis of flea allergy dermatitis (FAD) or flea bite hypersensitivity was studied in cats. A functional in vitro test (FIT) for sensitized type I allergic effector cells was used to evaluate the degree and kinetics of in vivo basophil sensitization against flea antigens in cats under long-term flea exposure. FIT results were compared with intradermal (IDT) and serological testing. Before, during, and after weekly repeated exposure to Ctenocephalides felis; 14 cats were repetitively FIT-assessed for general and flea-specific sensitization. In three cats, flea-specific sensitization was seen before and throughout flea exposure. Five cats, although generally sensitized, never developed a flea-specific sensitization. Six cats initially FIT-negative became sensitized for flea antigen during flea infestation. Induction, upregulation, and binding of C. felis-specific sensitizing antibodies to basophils during flea challenge may explain the developing sensitization in these cats. Strong discrepancies between the levels of flea-specific circulating IgE and basophil sensitization contrasted comparable results for basophil and mast cell sensitization using FIT and IDT, respectively. Hence, the FIT might provide an immunological supplement to the clinical diagnosis of FAD in cats by elucidating the state of basophil-sensitization to flea antigens. And it may be a comfortable alternative to IDT.

Dictyocaulus viviparus seroprevalence and epidemiology in Costa Rican dairy cattle.

A cross-sectional serological survey of Dictyocaulus viviparus was carried out to determine the prevalence of lungworm infections in 28 dairy cattle farms distributed in five selected areas from Costa Rica. The influence of area, farm, host (breed, age and lactation number) and ecological factors (altitude and life zones) on the presence of lungworm infection was analyzed. A sub-sample of 924 sera collected between September 1998 and July 1999 was processed by ELISA (Ceditest). A total of 162 (17.5%) animals from 26 (93.0%) farms showed antibodies against D. viviparus. The overall seroprevalence detected among areas was Poás 25.0%, Cartago 24.3%, Tilarán 22.0%, Alfaro Ruiz 12.0% and San Carlos 12.1%. Using analysis of variance no significant influence of area and host factors on D. viviparus infections was determined, whereas the variable farm within area was highly significant (p<0.001). However, altitude and life zones showed significant association to seropositive animals, when a Chi-square test was applied. In altitudes of 1000-2000 m (p<0.001) and life zones of Lower Montane moist forest and Montane moist forest (p<0.001) D. viviparus infections in bovines were significantly higher. The results obtained in this study indicate a high D. viviparus seroprevalence in the analyzed farms and that the factors farm, altitude and life zones were significantly related to lungworm infections.

Prevalence of Toxocara spp., Toxascaris leonina and ancylostomidae in public parks and beaches in different climate zones of Costa Rica.

This epidemiological study was conducted in different regions of Costa Rica to determine the prevalence of the developmental stages of potential zoonotic intestinal helminths of dogs and cats in public places. Samples were collected within three main climate zones including rural and urban areas during both the rainy and the dry season. Faecal and environmental samples were taken from 69 parks and beaches. Of the faecal samples 3% contained Toxascaris spp. eggs, 7% Toxocara spp. eggs and 55% contained ancylostomidae eggs. Of the soil samples, 2% contained ancylostomidae eggs and 0.8% contained ascarid eggs. Significant differences in the presence of parasites were found in faecal samples of dry, moist and wet climate zones and between the dry and rainy seasons. Significant differences in the presence of eggs and larvae were also found in the grass samples in the dry, the moist and the wet climate zones and between the different seasons. No significant differences were found between rural and urban areas.

Dynamics of infections with gastrointestinal parasites and Dictyocaulus viviparus in dairy and beef cattle from Costa Rica.

A longitudinal survey was carried out to determine and describe the prevalence and intensity of gastrointestinal parasite infections and Dictyocaulus viviparus in a dairy and a beef cattle farm of two different ecological zones in Costa Rica. The influence of anthelmintic treatment, age and meteorological factors (rainfall, minimum and maximum temperatures) on gastrointestinal nematodes and D. viviparus counts was determined. Calves were subjected to monthly sampling of feces and blood between April 2002 and March 2003. Coprological techniques were used to detect gastrointestinal helminthes, protozoan and D. viviparus. Blood samples were analyzed for antibodies to D. viviparus by ELISA. The most prevalent gastrointestinal parasites detected on both farms (dairy cattle, A; beef cattle, B) were Eimeria spp. (94.7%, 93.7%), Strongylidae (75.0%, 81.4%), Buxtonella sulcata (38.0%, 21.6%) and Strongyloides papillosus (29.8%, 31.7%), whereas Moniezia benedeni (4.8%, 9.1%), Trichuris spp. (7.3%, 13.2%), Toxocara vitulorum (0.0%, 1.8%) and Entamoeba bovis (2.5%, 1.1%) were less prevalent. Mean fecal egg counts (FEC) showed highest values of Strongylidae in April, May and July (>335.3 eggs/g feces) on farm A, and April, May and August (>304.3 eggs/g feces) on farm B. S. papillosus presented low FEC throughout the year on farm A, on farm B the highest values were obtained in April (303.0 eggs/g feces). Trichuris spp. presented maximum FEC values in May (328.6 eggs/g feces) on farm A and in June (157.5 eggs/g feces) on farm B. Treatment and age had significant influence on infection intensity of Strongylidae (farms A and B), S. papillosus (farms A and B) and Trichuris spp. (farm A). Rainfall had significant effect on S. papillosus (farms A and B) and Trichuris spp. (farm B). Maximum temperature showed significant effect on S. papillosus (farm A) and Trichuris spp. (farms A and B). Minimum temperature had significant influence on Strongylidae (farm A), S. papillosus (farms A and B) and Trichuris spp. (farm B). Haemonchus spp. (57%, 66%) and Cooperia spp. (30.0%, 30.7%) were the most prevalent genera identified by coproculture on both farms, in contrast, Trichostrongylus spp. and Oesophagostomum spp. were less frequent. Patent lungworm infections were low on both farms (10.8%, 1.8%). On farm A, high prevalence of antibodies against D. viviparus was determined only at the beginning of the study, in contrast, on farm B the seroprevalence fluctuated throughout the year. Treatment, age and maximum temperature had significant effect on D. viviparus counts on farm A, but not on farm B.

Evaluation of a serological method for the detection of Taenia saginata cysticercosis using serum and meat juice samples.

Two peptides, HP6-2 and Ts45S-10, were used as antigens for the detection of antibodies against Taenia saginata cysticercosis in serum and meat juice samples using enzyme-linked immunosorbent assay (ELISA). Positive control samples were obtained from animals experimentally infected (serum) and from animals naturally infected (meat juice). The two peptides and a pooled preparation of both peptides were evaluated, and their cut-off points with both sample categories were calculated. ELISA results from these different peptides were compared. Sensitivity and specificity of HP6-2 using serum were calculated as being 100 and 98%, respectively, showing to be higher than the values for the other antigens used. The average optical density (OD) value for negative samples was 0.646, whereas it was 1.702 for the positive control samples. This peptide was used to examine serum samples from animals with cysts and random field serum samples. For meat juice samples the pooled peptides showed the highest sensitivity and specificity, as they were 100 and 95%, respectively. The average OD values for the negative and the positive reference meat juice samples were 0.379 and 1.291, respectively. The optimal dilution of the meat juice samples for the ELISA was very low, as it was 1:20 using the pooled peptides, compared with 1:800 serum dilution using HP6-2. To the authors' knowledge, this is the first report of a successful testing for T. saginata cysticercosis using meat juice.

Detection of a gypsy-like sequence in the genome of the cat flea Ctenocephalides felis (Bouché 1835).

The gypsy virus of Drosophila melanogaster is the first identified retrovirus of insects. Its infectious properties have been reported, and it is able to cause diverse mutations of the phenotype in the fruit fly. As a typical endogenous retrovirus, it is transmitted vertically as part of the host genome, but horizontal transmission has also been shown for the D. melanogaster gypsy virus. Using polymerase chain reaction with degenerate primers designed from the gypsy element of Drosophila subobscura, a gypsy-like sequence was amplified from the genome of the cat flea Ctenocephalides felis in a pool of laboratory and field strains. High identities with other gypsy-like sequences of Drosophila spp. can be detected. In contrast to some of these gypsy sequences, the 410-bp fragment of C. felis possesses two deletions, which are localised in the env gene region. Because of these deletions and the lack of virus particles in C. felis, the criteria for host infectivity are not fulfilled. Nevertheless, the general detection of a gypsy-like sequence in C. felis and the capability of the ectoparasite to act as transmitter of viral diseases can be of importance for the cat flea's position in the epidemiology of diseases, which are accompanied by a higher rate of mutation.

Cases of reduced cyathostomin egg-reappearance period and failure of Parascaris equorum egg count reduction following ivermectin treatment as well as survey on pyrantel efficacy on German horse farms.

In 2003 and 2004, on a total of 63 different German horse farms, a survey using the faecal egg count reduction (FECR) test was performed to investigate the efficacy of ivermectin (IVM, Ivomec) and pyrantel (PYR, Banminth) treatment against gastro-intestinal nematodes in a total of 767 horses. IVM treatment resulted in 100% reduction of the cyathostomin egg production 14 and 21 days post-treatment (d.p.t.) on 37 farms. On the remaining five farms, the mean faecal egg count reduction ranged between 97.7 and 99.9%. The mean cyathostomin FECR following PYR treatment ranged between 92.2 and 100% on the 25 farms tested. Therefore, based on the 90% FECR threshold suggested for detection of anthelmintic resistance in horses, neither IVM nor PYR anthelmintic resistance was detected. However, if the thresholds recommended for the detection of resistance in small ruminants were applied, on one and four farms signs of reduced IVM and PYR efficacy, respectively, were observed. In 2005, to further investigate these findings, the cyathostomin egg-reappearance period (ERP) following IVM treatment was examined on six selected farms, two of which were found to show less than 99.8% FECR in the previous survey. On these two latter farms, the ERP was less than 5 weeks, while on the other four it was at least 8 weeks. Earlier investigations described IVM cyathostomin ERP of at least 9 weeks. The efficacy of IVM to reduce Parascaris equorum egg excretion was also studied. On one farm in 2 consecutive years, IVM treatment did not lead to a significant reduction in P. equorum faecal egg counts in one and five young horses, respectively.

Visual diagnosis of Taenia saginata cysticercosis during meat inspection: is it unequivocal?

A total of 267 cysts were collected from March to December 2004 from two main abattoirs in northern Germany. The cysts were classified by the usual organoleptic methods during meat inspection as Cysticercus bovis. The reported prevalence of cysticercosis in the abattoirs was 0.48 and 1.08%, respectively. The cysts were examined macroscopically for description of their morphology and constituents and classified as viable or degenerating (dead). The DNA was extracted from these cysts and subjected to polymerase chain reaction (PCR) for evaluation of the detection methods used and to make certain that the cysts did indeed belong to C. bovis, as indicated at the slaughterhouses. Two sets of primers were used with different sensitivity levels. The first, HDP1, was able to detect 200 fg of Taenia saginata DNA and 100 pg of C. bovis DNA. The other primer set, HDP2, was able to detect 1 pg of T. saginata DNA and 1 ng of C. bovis DNA. No more than 52.4% of the samples tested positive for C. bovis in the PCR using both primers, while 20% of the viable cysts and 49.2% of the degenerating cysts tested negative with both primers.