Experimental Infection

The clinical and virological protection induced by an E2 sub-unit marker-vaccine against Classical Swine Fever (CSF) was examined during an experimental infection in vaccinated and non-vaccinated pigs. Forty-®ve pigs were equally distributed over three adjacent pens of an isolation unit, there was only indirect (airborne) contact between pigs in the dierent pens. In pen 3 all pigs were vaccinated twice with 4 weeks interval. Pigs in pens 1 and 2 were not vaccinated. Two weeks after booster vaccination, one randomly selected pig in the middle pen was experimentally inoculated with CSF virus. After the initial virus spread in the infected pen, all pigs in the non-vaccinated adjacent pen were infected. In the vaccinated pen, seven out of 14 pigs became infected during the experiment. Survival analysis showed that virus transmission by direct and indirect contact was signi®cantly p`0X001 delayed in vaccinated pigs as compared to non-vaccinated pigs. In the non-vaccinated pens over 40% of the pigs died and typical clinical signs were noticed. In the vaccinated pen no mortality and no clinical symptoms were observed. Although double vaccination with an E2 sub-unit marker-vaccine was able to prevent the clinical course of the disease it was unable to prevent infection through indirect contact. This ®nding combined with the slow serological response after vaccination will complicate the possible use of the vaccine in emergency vaccination programmes. 7

In order to study B. henselae transmission among cats, five young cats were kept in confinement for two years, one of them being inoculated by SC route with B. henselae (10 5 UFC). Only occasional contact among cats occurred but the presence of fleas was observed in all animals throughout the period. Blood culture for isolation of bacteria, PCR-HSP and FTSZ (gender specific), and BH-PCR (species-specific), as well as indirect immunofluorescence method for anti-B. henselae antibodies were performed to confirm the infection of the inoculated cat as well as the other naive cats. Considering the inoculated animal, B. henselae was first isolated by blood culture two months after inoculation, bacteremia last for four months, the specific antibodies being detected by IFI during the entire period. All contacting animals presented with bacteremia 6 months after experimental inoculation but IFI did not detect seroconversion in these animals. All the isolates from these cats were characterized as Bartonella (HSP and FTSZ-PCR), henselae (BH-PCR). However, DNA of B. henselae could not be amplified directly from peripheral blood by the PCR protocols used. Isolation of bacteria by blood culture was the most efficient method to diagnose infection compared to PCR or IFI. The role of fleas in the epidemiology of B. henselae infection in cats is discussed.

Hydatidosis is endemic in Neuquén, Patagonia, Argentina, even though sanitary authorities have been performing a control programme since 1970. At present, the programme is in consolidation phase, and dogs have being evaluated by arecoline purgation. The aims of this study were to evaluate diagnostic performance of a coproantigen (CAg) ELISA test developed "in house" and to assess CAg detection in prepatent period. We examined 8 dogs experimentally infected with Echinococcus granulosus and 403 rural dogs in an endemic area in Neuquén using CAg ELISA test and arecoline purgation. Within the experimental dog group, sensitivity and specificity of the test were 93.6% and 88.5% respectively. In rural dogs group, the overall prevalence of canine echinococcosis was 3.7% using arecoline purgation and 12.4% by the CAg test; sensitivity and specificity of the test using arecoline purge as standard were 73.3% and 89.9% respectively. Possible cross reactions in CAg test were evaluated in rural dogs: CAg was undetectable in 96.4% of the dogs infected only with taeniids nonE. granulosus, and in 90.1% of dogs infected with non-taeniid helminths. The CAg test could detect infections within prepatent period and produced negative results after worm expulsion. Our test showed adequate diagnostic performance with experimentally and naturally infected dogs, in the epidemiological situation of Neuquén. Employment of this sensitive and practical method for surveillance in the control programme in Neuquén would improve screening of canine echinococcosis by detecting infected dogs even with low burdens or within prepatent period.

Human schistosomiasis is associated with IgE and eosinophilia, feature of a type 2 response. In experimental investigations, murine model has been widely used in order to dissect the immune responses involved in the expression of protective immunity or disease in Schistosoma mansoni infection. Collectively, observations made in this model and in humans demonstrated a strong contrast since a Th2 response in infected mice is involved in the expression of pathology, however, in infected humans the same type of response is rather beneficial for the host. This review will consider the relevance of extrapolating studies of immune responses from experimentally infected rats a semi-permissive host, to studies on S. mansoni infected humans. ᮊ

During the period from July 2002 to June 2003, infectious bursal disease (IBD) was suspected in 101 commercial flocks of broiler chickens on the basis of clinical and post mortem findings in some districts of the Haryana state, India. Bursal samples were collected randomly from 20 flocks for the detection of infectious bursal disease virus (IBDV) by reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR assay. IBDV could be detected in 17 samples as evidenced by amplification of 643 bp fragment of the very variable region of VP2 gene of virus by agarose gel electrophoresis. The authenticity of the amplicons was further confirmed by nested PCR generating amplicons of 552 bp using internal primers.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

To better understand the potential environmental health risk presented by West Nile virus (WNV)-contaminated feces, we quantified the amount of WNV present in the feces of experimentally infected American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus). Peak fecal titers ranged from 10(3.5) to 10(8.8) plaque-forming units (PFU)/g for 10 American crows and from 10(2.3) to 10(6.4) PFU/g for 10 fish crows. The presence of infectious WNV in bird feces indicates a potential for direct transmission of WNV. Thus, handlers of sick or dead birds should take appropriate precautions to avoid exposure to fecal material.

One-step multiplex RT-PCR assay for the detection of peste des petits ruminants virus in clinical samples Veterinary Research Communications, 30(6), 655-666 ABSTRACT A single-tube one-step multiplex RT-PCR was standardized to amplify both 337 bp and 191 bp fragments of N and M genes of peste des petits ruminants virus (PPRV), respectively, and only a 337 bp fragment of N gene of Rinderpest virus (RPV). The RT-PCR using purified viral RNA was easily adopted for direct detection of PPRV in clinical field samples and its differentiation from RPV. The amplified N and M gene products were confirmed to be PPRV-and RPV-specific by their size in 1.5% agarose gel and restriction analysis. In the assay, the Qiagen one-step RT-PCR kit containing the Ominiscript and Sensiscript reverse transcriptases and Hot star Taq DNA polymerase was utilized. The sensitivity of the assay was found to be 100 fg of PPRV RNA. Compared with a two-step assay, the one-step assay is easier and time-saving as it requires just a single buffer for both reactions, reverse transcription (RT) and PCR. In experimentally infected goats, PPRV was detectable by the one-step RT-PCR in nasal and ocular swabs 7-17 days post infection (p.i.). and in oral swabs 7-15 days p.i. Out of 32 clinical field samples tested, 18 were positive by sandwich ELISA (S-ELISA), while 22 were positive by the one-step RT-PCR.

In the present study we collected 177 serum samples from ostriches (Struthio camelus) infected experimentally with A/ostrich/South Africa/Middleton/2004 (H5N2) highly pathogenic avian influenza virus. We tested these samples using the haemagglutination inhibition (HI) test, the agar gel immunodiffusion test and three enzyme-linked immunosorbent assay kits. We considered the HI test, with homologous antigen and including pre-treatment of sera with 10% chicken red blood cells, as the gold standard. Detectable specific antibodies appeared on day 7 post-infection and persisted until the termination of the experiment. The relative sensitivity and specificity of the tests under evaluation and Cohen's K value were calculated. The results reported herein could be of assistance to decision-makers in drafting guidelines for the definition of the health status of ostriches and for trade purposes.

ABSTRACT Guava (Psidium guajava) fruit is vulnerable to postharvest diseases, such as anthracnose. In the present study, molecular characterisation and pathogenicity of Colletotrichum associated with antharcnose disease of guava fruit were conducted. From anthracnose lesion of guava, 20 isolates were successfully recovered. Based on colony colours, conidia, appressoria and presence or absence of setae, and ITS regions and ß-tubulin gene sequences, the isolates were identified as Colletotrichum gloeosporioides. Phylogenetic analysis based on combined data-sets using neighbour-joining method showed that C. gloeosporioides isolates did not group with C. gloeosporioides epitype strain, and thus the isolates were referred to as C. gloeosporioides species complex or C. gloeosporioides sensu lato. Pathogenicity tests using wounded treatment showed that C. gloeosporioides isolates from guava were pathogenic causing anthracnose on the fruits. The present study showed that C. gloeosporioides sensu lato is the most common species causing antharcnose disease of guava fruit.

Although the use of tanniferous plants or condensed tannins as an alternative to anthelmintics to control gastrointestinal nematodes has been largely documented in sheep, studies remain scarce in goats. The objective of this study was therefore to assess the possible impact of condensed tannins in goats infected with adult Haemonchus contortus. Two groups of cull goats were experimentally infected with 10.000 L3 of H. contortus. After 4 weeks, quebracho extracts, representing 5% of the diet DM, were administered for 8 days to one of the two groups. Goats of the second group remained as controls. One week after the end of quebracho administration, the goats were euthanised. Individual egg excretion and pathophysiological parameters were measured weekly during the study. At the end of the study, worm counts were assessed and histological samples from the abomasa were taken to count the numbers of mucosal mast cells, globule leukocytes and eosinophils. The administration of tannins was associated with a significant decrease in egg excretion, which persisted until the end of experiment. This reduction was not associated with any difference in worm number but with a significant decrease in female fecundity. No significant changes in the mucosal density of the three inflammatory cell types were detected between the two groups. These results indicate that the major consequence of tannin consumption in goats is a reduction in worm fecundity and egg output, which does not seem related to significant changes in the local mucosal response.

Anaplasmosis, caused by the tick-borne rickettsia, Anaplasma marginale, is an economically important disease of cattle in the United States and worldwide. Cattle that recover from acute infection become carriers in which low or microscopically undetectable A. marginale rickettsemia persists. Tetracycline antimicrobials are currently the only drug used in the US for treatment of acute anaplasmosis. There are currently no drugs specifically licensed for elimination of persistent infections. This study tested the efficacy of three oxytetracycline treatment regimens to clear A. marginale from cattle that were persistently infected. Forty Angus  Simmental steers, aged 6-12 months were experimentally infected with A. marginale. After the steers recovered from acute infection, seroconverted, and were confirmed infected using nested PCR followed by DNA hybridization, the carrier status of each animal was ascertained by sub-inoculation of blood into a separate, splenectomized Holstein calf. The steers were then blocked by bodyweight and randomly assigned as follows to four treatment groups: Treatment A, 300 mg/ml solution of oxytetracycline (Tetradure LA-300, Merial Canada Inc.) administered at 30 mg/kg, by intramuscular (IM) injection on day 0; Treatment B, the same 300 mg/ml solution of oxytetracycline administered at 30 mg/kg, IM on day 0 and again on day 5; Treatment C, a 200 mg/ml solution of oxytetracycline (Liquamycin LA-200, Pfizer Animal Health) administered at 22 mg/kg, intravenously (IV), q 24 h for 5 days (a treatment dose that corresponds with current Office International des Epizooties (OIE) recommendations for treatment prior to export). The fourth group consisted of untreated infected control cattle. All steers were still nested PCR and cELISA positive at 60 days after treatment. Infection was confirmed by subinoculation of blood into a www.elsevier.com/locate/vetpar Veterinary Parasitology 127 61-73 splenectomized Holstein calf. These results demonstrated that the treatment regimens tested failed to clear A. marginale infections in carrier cattle. #

Pigs, asymptomatically infected with Actinobacillus pleuropneumoniae in their upper respiratory tract, can transmit the infection. Detection of such animals is indispensable to prevent the intake of the disease in a herd. This study was conducted to evaluate bacteriology, polymerase chain reaction (PCR) and serology for the detection of subclinically infected pigs. Pigs were inoculated onto the tonsils with an A. pleuropneumoniae serotype 9 strain (n ¼ 12, group 1) or phosphate buffered saline solution (PBSS) (n ¼ 5, group 2). To prevent infection of the lungs, pigs of group 1 were treated three times with sodium ceftiofur as an aerosol. A third group ðn ¼ 5Þ was inoculated intranasally with the same strain. All animals were euthanized 30 days post-inoculation (dpi). In pigs of group 1, clinical signs were not observed. A small lung lesion was found in only one pig and A. pleuropneumoniae was isolated from this lesion. The bacterium was not isolated from the lungs of animals that did not develop lung lesions. A. pleuropneumoniae was demonstrated in tonsils of 9/12 animals using bacteriological isolation, whereas it was demonstrated in mixed bacterial cultures from tonsils of all 12 animals by PCR. In non-infected animals (group 2), clinical signs were not observed and A. pleuropneumoniae was not demonstrated in any sample. All intranasally infected animals (group 3) developed disease signs and lung lesions. High antibody titers against ApxI, ApxII and heat-stable antigens were detected in animals that developed lung lesions. Antibody titers against these antigens were low or absent in all other pigs. It was concluded that pigs carrying A. pleuropneumoniae in the upper respiratory tract generally do not show measurable antibodies in serum. Therefore, sensitive Veterinary Microbiology 88 (2002) 385-392 : S 0 3 7 8 -1 1 3 5 ( 0 2 ) 0 0 1 5 0 -5 methods for the detection of the etiological agent such as PCR are required to identify carrier animals, while serological methods are not suitable. #

Different transmission routes, including the ingestion of undercooked meat, can result in Toxoplasma gondii infection in humans. The development of effective prevention strategies is hampered by a lack of quantitative information on the contamination level of different types of meat. Therefore, we developed a method for detection and quantification of T. gondii. The method involved preparation of crude DNA extract from hundred gram samples of meat, magnetic capture of T. gondii DNA and, quantitative real-time PCR targeting the T. gondii 529-bp repeat element. The detection limit of this assay was approximately 230 tachyzoites per 100 g of meat sample. There was a linear relation between the number of parasites added to the samples and Cp-values. Results obtained with the PCR method were comparable to bioassay results for experimentally infected pigs, and to serological findings for sheep. In addition, the T. gondii in 50% of the positive sheep samples could be genotyped by sequencing of the GRA6 gene, after isolation of the gene by magnetic capture. Two subtypes of GRA6 type II were identified in the 16 samples from sheep. For seven samples, the identification of T. gondii as type II was confirmed by microsatellite typing. The PCR method can be used as an alternative to bioassay for detection and genotyping of T. gondii, and to quantify the organism in meat samples of various sources.

The efficacy of triclabendazole in sheep experimentally infected with Fasciola hepatica was studied. Two groups of 12 lambs were infected with a susceptible (S) or a resistant (R) strain of F. hepatica. Eight weeks after infection, six lambs of each group (ST and RT) were treated with triclabendazole (10 mg/kg). The other lambs were used as untreated controls (SC and RC).

A PCR assay was developed for the detection of Streptococcus suis serotypes 2 and 1/2. This multiplex PCR is based on the amplification of the gene coding for 16S rRNA of S. suis and on the amplification of the cps2J gene coding for the capsule of S. suis serotypes 2 and 1/2. An internal control was constructed and added in this test to monitor the efficiency of amplification in each reaction. To evaluate the specificity of the test, 31 strains of other bacterial species related to S. suis or isolated from pigs and 42 strains of S. suis serotypes 1 and 3 to 34 were analyzed. The detection threshold of the test was 28 S. suis CFU/ml. The specificity and the sensitivity of the multiplex PCR test and the presence of an internal control allowed the analysis of biological samples without a culture step. The PCR assay was then applied to the detection of 14 S. suis serotype 1/2 strains, 88 S. suis serotype 2 strains isolated from pigs, and 25 S. suis serotype 2 strains isolated from humans. This test was also applied to analyze tonsil samples of pigs experimentally infected and carrier pigs without any symptoms.

FTIR microscopy was used to detect and discriminate the two wood decaying fungi Trametes versicolor and Schizophyllum commune in experimentally infected beech wood blocks. The distribution of fungal mycelium in wood was locally resolved and semiquantitatively recorded using FTIR microscopy combined with a focal plane array detector and image analysis. Cluster analysis revealed major diVerences between FTIR spectra recorded from wood Wbers and empty vessel lumina and spectra from mycelium of both fungal species, irrespective of whether the fungi were grown on the surface of wood or inside vessel lumina. Species-speciWc clustering of spectra of fungal mycelium grown on the wood surface and inside vessel lumina demonstrated the potential of FTIR microscopy to discriminate among fungal species decaying wood. 

Concurrent infections provoked by the sea lice Lepeophtheirus simplex and the monogenean Neobenedenia sp. on bullseye puffer fish Sphoeroides annulatus, reared in tanks, have been related to skin pathology and mortality. Freshwater treatment is widely used to treat two parasite groups, but the results differ depending on the parasite species, life stage and exposure time. The present study describes the effectiveness of freshwater treatments to remove both parasites. Sea lice nauplii and free swimming copepodids, reared in the laboratory, were exposed to freshwater treatments for periods from 30 s to 16 min. Fish experimentally infected with sea lice or monogeneans were exposed to freshwater for 15 to 90 min and 10 to 60 min, respectively. All sea lice nauplii and copepodids were killed by freshwater dips at 2.5 and 14 min, respectively. For pre-adult and adult sea lice, 30 and 60 min of freshwater exposure significantly reduced up to 95 and 99% respectively. However, most freshwater exposures did not reduce chalimus stages more than 10%. Immature and adult populations of monogeneans showed a significant reduction of 95% at 20 min of exposure. These results indicate that, if used properly, freshwater baths constitute an efficient alternative to control these mixed ectoparasite infections on bullseye puffer fish reared in tanks.

Using the enteropathogenic Escherichia coli (EPEC) genome sequence, we found that EPEC E2348/69 has an lpfABCDE gene cluster homologous (about 60% identical at the protein level) to the Salmonella long polar fimbria (LPF) operon. To determine whether this operon is essential for adherence, the lpfABCD E23 genes were deleted from EPEC strain E2348/69 by allelic exchange. Analysis of the resulting EPEC⌬lpfABCD E23 strain showed no change in adherence to HeLa cells or to human intestinal biopsy cells in the in vitro organ culture (IVOC) system compared to the wild type. Sera from volunteers experimentally infected with E2348/69 showed no antibody response to the major subunit protein, LpfA. These results suggested that the lpf E23 gene cluster is

The hard clam, Mercenaria mercenaria, has been affected by severe mortality episodes associated with the protistan parasite QPX (Quahog Parasite Unknown) for several years. Despite the commercial importance of hard clams in the United States, molecular bases of defense mechanisms in M. mercenaria, especially during QPX infection, remain unknown.

Isospora suis ist ein einzelliger Parasit des Schweins und der Erreger der Saugferkelkokzidiose. Diese Erkrankung zeigt eine hohe Morbidität in betroffenen Ferkelzuchtbetrieben und ist damit ein wichtiger wirtschaftlicher Faktor in der Schweineproduktion. Im Verlauf der Infektion wird die Schleimhaut des Dünndarmepithels in Jejunum und Ileum stark geschädigt, was zu charakteristischen unblutigen Durchfällen führt. Eine Folge der reduzierten Nährstoffaufnahme im so geschädigten Dünndarm sind verminderte Absetzgewichte und ein starkes Auseinanderwachsen der Würfe, zusätzlich können Sekundärinfektionen mit anderen Darmpathogenen die Mortalitätsrate erhöhen. Trotz der wirtschaftlichen und veterinärmedizinischen Bedeutung der Saugferkelkokzidiose sind die Interaktionen zwischen Wirt und Parasit bislang nur unzureichend aufgeklärt. Dieser Übersichtsartikel befasst sich mit dem Lebenszyklus von I. suis und den klinischen und parasitologischen Charakteristika der Saugferkelkokzidiose. Weiters werden verschiedene Modelle der experimentellen Infektion und etablierte in vitro-Methoden zur Erforschung von I. suis vorgestellt. Er gibt einen Überblick über die natürliche Altersresistenz gegen Infektionen mit I. suis, die Immunantwort verschiedener Wirte bei anderen Kokzidieninfektionen (Eimeria spp., Cryptosporidium muris) und eine Zusammenfassung der Besonderheiten des Immunsystems des Schweins und seiner Entwicklung in den ersten Lebenswochen. Isospora suis, an intestinal protozoan parasite of swine, is the causative agent of neonatal coccidiosis, a disease with high morbidity in affected pig-breeding units and consequently of high economic importance. Infection leads to damage of the mucosal surface in the jejunum and ileum and to non-haemorrhagic diarrhoea. As a result, weight gain of piglets is reduced and secondary infections with other enteric pathogens may lead to increased mortality. Despite its economic and veterinary importance, host-parasite interactions are still poorly understood. To examine these interactions experimental infection models are established using outbred piglets infected with defined numbers of parasites on different days of life. This review discusses the life cycle of Isospora suis and the clinical and parasitological characteristics of porcine neonatal coccidiosis including pathology, and compare the different experimental infection models and the tools for studying Isospora suis in vitro. Moreover, it summarises findings about natural age resistance of pigs against infections with Isospora suis, our current knowledge about immune response to other coccidial infections, e.g. with Eimeria spp. in different hosts, and gives a short overview on peculiarities of the porcine immune system and its development in young animals which may play a role in porcine coccidiosis.

Summary Kirkova, Z., P. Petkov & D. Goundasheva, 2005. Clinical and haematological studies in dogs, experimentally infected with Trichuris vulpis. Bulg. J. Vet. Med., 8, No 2, 141�148. The experiment was performed on 9 mixed-breed dogs (6 infected and 3 non-infected controls). The experimental infection was provoked with Trichuris vulpis (10000 eggs/kg). The clinical signs and the following haematological parameters were monitored: haemoglobin, packed cell volume, red blood cell counts and morphology, mean corpuscular haemoglobin (MCH), mean corpuscular hae- moglobin concentration (MCHC), mean corpuscular volume (MCV), haemoglobin index (HbI), erythrocyte sedimentation rate (ESR), total and differential white blood cell counts. A typical clinical signs of the disease was the diarrhoea that resulted in full exhaustion and cachexia. In infected dogs, elevated haemoglobin and MCH values were observed between post infec- tion days 60 and 207, decreased MCV by day 15 and 35 and no change...

This research is the first record of the infection of Apis florea by Nosema ceranae, a newly identified pathogen of honeybee in Thailand which was initially isolated from A. florea workers. Each Nosema free-bee was fed 2 μl of 50% (w/v) sucrose solution containing 0, 10,000 20,000 or 40,000 Nosema spores/bee. The survival rates of treated bees were significantly lower compared to control bees. Infectivity was not statistically different among the three spore concentrations, whereas no infection was found in control bees. Protein content of control bee hypopharyngeal glands 14 days post inoculation (p.i) was significantly higher (21.47± 0.17 mg/bee) compared to all treatments. The infection ratio of bees treated with 40,000 spores/bee increased with time after inoculation. These results suggest that N. ceranae has a significant negative effect on honeybee hypopharyngeal gland protein production and contributes to their shortened life span.

To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of

Skin physiology in cats has received little attention. The aim of this study was to evaluate the long-term influence of sex, time and the level of dietary fat and energy on the dynamics and qualities of the hair coat. Twenty-four European short-haired laboratory cats were followed over a 1-year period. They were divided into eight groups of three, according to: sex (12 males and 12 females), sexual status (intact or neutered) and diets [(high energy 4300 kcal/kg as fed, 21% fat) vs. (moderate energy 3500 kcal/kg as fed, 10% fat)]. Both diets were fed for 6 months to all cats following a cross-over design. The following parameters were evaluated throughout the study: thickness of hair coat and hair lengths (neck, rump, lateral, flank), hair regrowth (after periodic clippings of 25 cm 2 areas), and telogen/anagen ratio. The thickness of the hair coat initially varied from 1.2-1.7 cm on the neck, 1-1.4 cm on the rump, 1.8-2.5 cm on the flank, and hair shaft lengths were 1.7-2.5, 3.7-3.9 and 2.5-3.2 cm, respectively. Comparison of values revealed few statistical differences: increase of the thickness of hair coat in neutered cats (male and female) during the study, and increase of the length of lateral hairs in all groups during the study. Over all periods and in all groups, the curve of growth was similar (rapid then slower). Some transient variations were attributed to temporary changes in ambient conditions. In conclusion, neither sex, nutrition or season (in housed cats) influenced the general quality of hair coat, in particular hair regrowth. Funding: Royal Canin. Veterinary Dermatology 2004, 15 (Suppl. 1), 41-69 Ó 2004 ESVD and ACVD 41 Poster Abstracts Poster Abstracts

Management of grazed grasslands for production and/or conservation objectives requires a thorough understanding of the choices of feeding sites by herbivores, and of the biological processes involved. Most models of the feeding strategies of herbivores are based on the principle that optimising the intake of energy (or some nutrient) is the primary goal of foragers but other selective forces, such as parasitism, could be important. Gastrointestinal parasites (including cyathostome nematodes) have powerful effects on the fitness of herbivores and may act as a major selection pressure favouring host behaviour that reduces the risk of encountering parasites. Among large herbivores, horses have perhaps the most marked tendency to select particular feeding sites within grasslands. We test here: (1) whether horses select feeding patches with relatively low parasite densities and (2) if their choice is affected by their parasite load. We used 10 two-year old saddle-horses and three periods. In the first period, the horses were under natural parasitism which varied strongly among individuals; in the second period they were all dewormed, and in the third, a sub-set of the horses was experimentally infected with cyathostome larvae. Ninety-eight percent of the infective larvae in the pasture were found <1 m from faeces. The main determinant of the choice of feeding patch by horses was the availability of patches of different parasite risk and grass height. Controlling for availability, the horses used tall grasses (>16 cm) less than expected, whether the grass was contaminated or not, and they selected for short patches >1 m from faeces, where the risk of encountering parasites was low. These results suggest that selection of feeding sites by horses is driven by an interaction between their nutritional and anti-parasite strategies: the horses avoid the patches of tall grass which are generally of low quality and areas contaminated by parasite larvae which leads them to prefer the patches of short grass far from faeces. The parasite status of the horses at the time of the experiment had no effect on their feeding choices. However, before concluding that the challenge by cyathostomes has no effect on the selection of feeding sites in horses, it will be necessary to test whether the history of parasitism of the individuals, rather than the current status, is important. #

Brucellergene OCB (Rhône-Mérieux) was used as an allergen to define the intrinsic parameters of a skin test and to compare its properties with serology for the diagnosis of bovine brucellosis. The skin test was also evaluated for its capacity to solve problems associated with false positive reactions in serological tests. The optimal reading delay for the skin test was 72 hours. The brucellosis allergic reaction was two to three times less intense than the tuberculosis allergic reaction. An increase of 1.1 mm or more in the skin thickness was therefore considered to be an adequate cut-off. The specificity calculated for 1192 brucellosis-free animals (including animals from brucellosis-free herds in which false positive serological reactions had been reported) was 99-83 per cent (95 per cent confidence interval [CI] 99-40 to 99-98 per cent). The sensitivity determined from 27 experimentally infected heifers ranged from 93 per cent (95 per cent CI 76 to 100 per cent) to 78 per cent (9...

This work evaluated the infection of opossums (Didelphis aurita) by Rickettsia felis, Rickettsia bellii, and Rickettsia parkeri and their role as amplifier hosts for horizontal transmission to Amblyomma cajennense and=or Amblyomma dubitatum ticks. Infection in D. aurita was induced by intraperitoneal inoculation with R. felis (n ¼ 4 opossums), R. bellii (n ¼ 4), and R. parkeri (n ¼ 2). Another group of six opossums were inoculated intraperitoneally with Leibovitz-15 sterile culture medium, representing the uninfected groups (n ¼ 2 opossums simultaneously to each infected group). Opossum blood samples collected during the study were used for DNA extraction, followed by real-time polymerase chain reaction targeting the rickettsial gene gltA, hematology, and detection of Rickettsia spp.-reactive antibodies by indirect immunofluorescence assay. Opossums were infested with uninfected A. cajennense and=or A. dubitatum for 30 days postinoculation (DPI). Flat ticks molted from ticks fed on opossums were allowed to feed on uninfected rabbits, which were tested for seroconversion by immunofluorescence assay. Samples of flat ticks were also tested by real-time polymerase chain reaction. Inoculated opossums showed no clinical abnormalities. Antibodies to Rickettsia spp. were first detected at the second to fourth DPI, with detectable titers until the 150th DPI. Rickettsemia was detected only in one opossum inoculated with R. parkeri, at the eighth DPI. Only one A. cajennense tick (2.0%) previously fed on a R. parkeri-inoculated opossum became infected. None of the rabbits infested with opossum-derived ticks seroconverted. The study demonstrated that R. felis, R. bellii, and R. parkeri were capable to produce antibody response in opossums, however, with undetectable rickettsemia for R. felis and R. bellii, and very low rickettsemia for R. parkeri. Further studies must be done with different strains of these rickettsiae, most importantly the strains that have never gone through in vitro passages.

Bovine herpesvirus 1 (BHV-1) is frequently associated with abortion in naturally and experimentally infected cattle. Most of the virus isolation and immunofluorescent antibody protocols described in the literature for detecting BHV-1 in bovine foetuses are rather laborious, costly and time-consuming. The detection is described of BHV-1 in the tissues of a naturally aborted bovine foetus by a nested PCR assay with no further hybridization procedures. Optimal results were achieved by filtering the foetal tissues on a chromatography column before DNA extraction, by using two pairs of primers in a nested PCR and by evaluating the amplification products on silver-stained polyacrylamide gels. This nested PCR was faster and easier to perform than the virus isolation test. To our knowledge, this is the first time that BHV-1 has been detected in the tissues of a naturally infected bovine foetus by means of a nested PCR. The test seems to be a practical alternative for rapid detection of BHV-...

An eighteen day trial was performed to evaluate the effect of necrotizing hepatopancreatitis (NHP) disease on the physiological, nutritional and immunological status of adult white shrimp (Litopenaeus vannamei). Shrimp were divided into infected and non-infected groups; infected shrimp were fed with hepatopancreas homegenates positive to NHP bacterium, while non-infected shrimp were fed with healthy hepatopancreas. No significant differences were observed for protein, glucose, acylglicerides, cholesterol, ammonia and urea concentrations in haemolymph. However, lactate levels increased by 95% in infected shrimp compared to non-infected shrimp at 18th day post inoculation; similarly, nitrite levels in infected shrimp significantly raised by 141% and 66% at 15th and 18th days respectively. The total phenoloxidase and phenoloxidase activities of infected shrimp increased significantly at 7th day post inoculation, whereas no significant differences were detected for prophenoloxidase and total hemocyte count. The antibacterial activity decreased in infected shrimp at 15th day post inoculation. Total proteinase, trypsin and quimotrypsin activities increased after 15 days from inoculation in infected shrimp; however trypsin and quimotrypsin activities returned to their original levels after 18 days. Results suggest that shrimp maintained a homeostasis status in most of the monitored parameters, while others were modified and returned to their original levels, indicating that shrimp can withstand the disease during the first phase by performing different physiological and biochemical modifications in order to maintain homeostasis (general adaptation syndrome).

The mainstay of tuberculosis diagnosis in cattle and deer has been the tuberculin skin test. Recent advances have allowed the incorporation of blood based assays to the diagnostic arsenal for both cattle and deer. Use of defined and specific antigens has allowed for improved specificity of cell mediated assays in both cattle and deer and advances in antibody tests for tuberculosis have potential for use in free-ranging and captive cervid populations. Combined use of blood-based assays with skin testing will require further understanding of the effect of skin testing on the accuracy of blood based assays. Models of experimental infection of cattle have allowed for increased understanding of natural disease pathogenesis. Differences likely exist; however, between cattle and deer in both disease distribution and primary route of inoculation in naturally infected animals. Published by Elsevier B.V.

There is large spatial and temporal variation in the Gyrodactylus parasite fauna across natural guppy (Poecilia reticulata) populations in Trinidad. The life history evolution of these fish could be affected differently in the various habitats depending on the local parasite selection pressure. Here, we experimentally infected three guppy populations with three gyrodactylid strains in the laboratory and monitored the infection by recording the number of parasites and host mortality in a full factorial design. The origin of the guppy population and parasite strain, and the size of the hosts explained significant variation in the survival of hosts. Larger fish carried the highest parasite loads and experienced the highest mortality rates, which suggests that parasite-mediated selection may favour smaller phenotypes, possibly counter-balancing selection pressures by gape-limited predators, mate choice and female fecundity. We observed significant variation in virulence between parasite strains with the captive-bred experimental strain (Gt3) causing the highest mortality of hosts whilst reaching only relatively low maximum burdens. This suggests that adaptations to the captive environment and/or inbreeding depression may alter the virulence of such captive-bred parasites. There were significant differences in survival rate between guppy populations, with infected guppies from the large population of the Lower Aripo River showing a higher survival rate than the fish from the small and genetically less diverse Upper Aripo River population. Ó

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The understanding of reciprocal interactions between Crassostrea gigas and Vibrio sp., whether these be virulent or avirulent, is vital for the development of methods to improve the health status of cultured oysters. We describe an original non-invasive experimental infection technique using cohabitation, designed to explore these interactions. Using real-time PCR techniques we examined the dynamics of virulent and avirulent Vibrio sp. in oyster hemolymph and tank seawater, and made a parallel study of the expression of four genes involved in oyster immune defense: Cg-BPI, Cg-EcSOD, Cg-IκB, Cg-TIMP.

A cDNA expression library prepared from Babesia gibsoni merozoite mRNA was screened with B. gibsoni- infected dog serum. cDNA encoding a 50-kDa protein was cloned and designated the P50 gene. The complete nucleotide sequence of the P50 gene was 1,922 bp. Computer analysis suggested that the sequence of the P50 gene contained an open reading frame of 1,401 bp with