ABSTRACT The complete surface glycoprotein (SU) nucleotide sequences of three French isolates of caprine arthritis-encephalitis virus (CAEV) were determined and compared with those of previously described isolates: three American isolates and one French isolate. Phylogenetic analyses revealed the existence of four distinct and roughly equidistant evolutionary CAEV subtypes. Four conserved and five variable domains were identified in the SU. The fine specificities of antibodies produced against these domains during natural infection were examined using a pepscan analysis. Nine immunogenic segments were delineated throughout the conserved and variable domains of SU, two of them corresponding to conserved immunodominant epitopes. Antigenic determinants which may be involved in the immunopathogenic process induced by CAEV were identified. These results also provide sensitive and specific antigen peptides for the serological detection and differentiation of CAEV and visna/maedi virus infections.

Semen and peripheral blood mononuclear cells (PBMC) samples of 15 infected and 3 non-infected bucks were evaluated for the presence of caprine arthritis–encephalitis virus (CAEV), by double-nested polymerase chain reaction (d-n-PCR). In order to locat the presence of vı́rus, semen samples were separated into cell-free seminal fluids (CFSF), enriched non-spermatozoal cells fraction (NSCF), and spermatozoa (SPZ). All PBMC samples from infected bucks were positive for CAEV-DNA but only 8 out of 15 semen samples were positive for CAEV-DNA. The presence of virus was not necessarily concordant in different fractions of semen from the same buck over time. In addition, the virus was isolated from CFSF in primary goat synovial membrane (GSM) cell culture, in which productive infection was demonstrated by syncytia formation. This is the first report describing the presence of CAEV-DNA and also of replication-competent virus in semen from CAEV seropositive bucks. Such results suggest the possibility of sexual transmission of CAEV.

Twenty-three sheep farms and 15 dairy goat farms, located in western France and randomly selected, were surveyed for gastrointestinal nematodes resistant to anthelmintics. On each of the 23 sheep farms, 60 lambs were randomly distributed into four groups of 15: untreated control group, fenbendazole (benzimidazole) group (5 mg/kg BW), ivermectin group (0.2 mg/kg BW) and levamisole hydrochloride group (6.8 mg/kg BW). On each of the 15 goat farms, 30 adult goats were allocated into two groups of 15: untreated control group and fenbendazole group (10 mg/kg BW). Faecal egg counts and larval cultures were done 10 to 14 days after anthelmintic treatment. Furthermore, egg hatch assays conducted with thiabendazole were performed on pooled faeces of fenbendazole treated goats, results being expressed as Logarithmic Concentration50 (LC50). Faecal egg count reductions (FECR) less than 95% are indicative of anthelmintic resistance and LC50 values above 0.1 μg/ml suggest benzimidazole (BZ) resistance. On this basis, in the sheep survey, anthelmintic resistance occurred on 83% of farms for benzimidazole and on 50% of farms for levamisole. Post-treatment larval cultures indicated Teladorsagia/Trichostrongylus and Cooperia were the predominant resistant genera. A negative relationship was found between FECR with fenbendazole and the average number of annual BZ treatments given to ewe-lambs (P<0.01). In contrast, no case of ivermectin resistant nematodes was seen in the 23 sheep farms. In goat survey, virtually all the 15 surveyed farms showed the occurrence of benzimidazole resistant nematodes according to the results of both FECR test and egg hatch assay. In post-treatment coprocultures, Teladorsagia/Trichostrongylus was the predominant larval type on seven farms, and Haemonchus on two farms, while on the remaining farms there was a well-balanced mixture of all the genera including Oesophagostomum/Chabertia. Although no relationship could be established between drenching practices and results of in vivo and in vitro tests, the frequent and sometimes exclusive use of BZ compounds associated with a permanent underdosing of these drugs achieved by using sheep dose rates are probably the main causes of the very high frequency of BZ resistance in nematodes on goats. The consequences of anthelmintic resistance on sheep and goat parasitism management are discussed.

Shedding of caprine arthritis encephalitis virus (CAEV) was assessed in semen and blood mononuclear cells of six bucks (four beers and two saanens) experimentally contaminated with a viral strain (CAEV Cork) and on three non-infected controls. CAEV was identified by polymerase chain reaction (PCR) in blood mononuclear cells of all infected animals but only in seminal fluid and non-spermatic cells of one buck and in non spermatic cells of another. presence of CAEV in semen could have implications in the dissemination and control of the disease. (C) Inra/Elsevier, Paris.

Shedding of caprine arthritis encephalitis virus (CAEV) was assessed in semen and blood mononuclear cells of six bucks (four boers and two saanens) experimentally contaminated with a viral strain (CAEV Cork) and on three non-infected controls. CAEV was identified by polymerase chain reaction (PCR) in blood mononuclear cells of all infected animals but only in seminal fluid and non-spermatic cells of one buck and in non-spermatic cells of another. Presence of CAEV in semen could have implications in the dissemination and control of the disease.

One hundred and eighty-seven dairy goats originating from 7 farms in western France were treated individually with febantel (probenzimidazole drug) at a dose rate of 5 mg/kg in spring 1991. Individual faecal samples were collected on d 0, 7 and 21 post-treatment and processed for counting first stage larvae of Muellerius capillaris (LPG: larvae per gram of faeces). Eggs of digestive tract strongyles were also counted on d 0 and 7 (EPG: eggs per gram of faeces). Blood samples were taken on d 0 to assess pepsinogen concentration related to abomasal damage caused by strongyle infection. The individual characteristics of the goats were recorded. The procedure was repeated on the same animals in autumn 1991. The faecal larval count reduction (FLCR) was mainly related to farm and season: farm 1 in the spring and farm 6 in the autumn showed a higher proportion of high responder (HR) goats (FLCR > 80%), whereas farm 3 exhibited a lower proportion of HR goats in the autumn. On the other hand, the characteristics of the goats (breed, physiological status, age, weight, presence or absence of wattles and horns) as well as the initial level of parasitism (LPG, EPG and pepsinogen concentration) all had a role which was limited or zero on the variability of response to treatment. Goats could not be individually categorized according to their response level because the FLCR values obtained in the spring were not repeated in the autumn, suggesting that other environmental parameters could be involved.

Serum samples from 533 strongyle-free goats were analysed to assess the normal values of pepsinogen concentration. Results obtained from adult goats (> 12 months) indicated higher values of pepsinogen compared with sheep and cattle, with more than 25% of the animals exceeding 1000 milliunits of released tyrosine (mU TYR). Weaned goats less than 6 months old had lower pepsinogen concentrations than the adult goats: 490 ± 175 mU TYR vs. 825 ± 414 mU TYR for the French Alpine breed and 397 ± 135 mU TYR vs. 709 ± 274 mU TYR for the Saanen breed. Saanen goats showed lower pepsinogen values than French Alpine goats. Additional sources of variation included farm and duration of lactation. Pepsinogen determinations were highly repeatable for 4.5 months, suggesting a pronounced stability of pepsinogen levels for the same non-infected animals.