Comparative pathogenicity of three genetically distinct types of Trypanosoma congolense in cattle: clinical observations and haematological changes

The pathology of African bovine trypanosomosis was compared in Zebu cattle subcutaneously inoculated with three clones of trypanosomes corresponding to the three genetically distinct types of Trypanosoma congolense; savannah-type, west African riverine/forest-type and kilifi-type. All inoculated animals became parasitaemic between 7 and 11 days post-infection (dpi). The savannah-type showed consistently higher levels of parasitaemia and lower packed red cell volume percentages and leukocyte counts than the other two types. The syndrome was also more severe in the savannah-type and led inexorably to death between 29 and 54 dpi while animals with the forest or the kilifi-types recovered from earlier symptoms and haematological alterations after 3 months of infection. By the end of the experiment, the animals self-cured from the forest-type infection and the kilifi-type passed under control. The results of the present study indicated clear difference in pathogenicity between the three types of T. congolense; the savannah-type was virulent while the forest-type was of low pathogenicity and the kilifi-type was non-pathogenic.     

Virucidal efficacy of four new disinfectants

Virucidal efficacy was evaluated for four recently available disinfectants: chlorine dioxide, potassium peroxymonosulfate, a quaternary ammonium compound, and citricidal (grapefruit extract). Sodium hypochlorite (3%) and tap water were used as positive and negative controls respectively. Feline herpesvirus, feline calicivirus, and feline parvovirus were exposed to the manufacturers' recommended dilutions of the evaluated disinfectants. Both chlorine dioxide and potassium peroxymonosulfate completely inactivated the three viruses used in this study. These disinfectants can aid in controlling nosocomial transmission of viruses with less of the deleterious effects of sodium hypochlorite. The quaternary ammonium compound evaluated in this study and citricidal were not effective against feline calicivirus and feline parvovirus.     

Occurrence of enteric redmouth disease in rainbow trout (Oncorhynchus mykiss) on farms in Croatia

During the spring of 1996 and autumn of 1997 unusual mortality outbreaks among rainbow trout fry and yearlings occurred at two different trout farms, resulting in mortality of 20 and 10 per cent, respectively. Generally, the affected fish, swimming at the water surface, were reluctant to eat and were dark pigmented with visible haemorrhages around and within the oral cavity. Bacterial isolates from moribund fish from both cases were identified as Yersinia ruckeri by standard biochemical tests and API 20E. The isolated strains were found to be sensitive to tetracycline, chloramphenicol, co-trimoxazole, nalidixic acid, flumequine, enrofloxacin, carbenicillin and gentamicin. Microplate agglutination assay confirmed that both isolates belonged to serotype O1. The pathogenicity of the isolated bacteria was confirmed by challenge experiment. Titres of specific antibodies were determined in the sera of survivors. The titre was highest on the 21st day postchallenge and was detectable until the 81st day.     

The effect of Alkanna tinctoria Tausch on burn wound healing in rabbits

Eighteen adult male New Zealand White rabbits were used in the treatment of partial thickness, severe and olive oil burns. Both right and left sides of the animals were burned to make partial thickness, severe and hot olive oil burn wounds. The solution of A. tinctoria TAUSCH in 16% prepared in medical olive oil in weight basis, were applied to the left, and right side served as control. It was topically applied twice a day by gently rubbing against the burn area. While complete healing of partial thickness and olive oil burn wounds occurred in 7 to 10, and 26 days, respectively, with well formed dermal-epidermal junctions in both groups, severely burned wounds appeared to be nonresponsive to A. tinctoria.     

Establishment of the baseline sensitivity and monitoring response of Papaver rhoeas populations to florasulam

In accordance with the EPPO guideline for the efficacy evaluation of plant protection products, resistance risk analysis PP 1/213(1), a method was established to determine the baseline sensitivity of key weed species to florasulam, a new triazolopyrimidine sulfonanilide herbicide for post-emergence control of dicotyledonous weeds in cereals. The aim of the baseline monitoring project was to understand the natural variation in response to florasulam of diverse populations of Papaver rhoeas at the time of product launch. The method entailed seed collection from representative agricultural areas throughout Europe. The seed was subjected to glasshouse tests where dose-response studies were conducted and ED80 values generated. This enabled a sensitivity index to be calculated for each country, giving an indication of the variation in P rhoeas response to florasulam in the populations tested.     

Genetic analysis of vesicular stomatitis virus-New Jersey from the 1995 outbreak in the western United States

OBJECTIVE: To compare molecular associations between the vesicular stomatitis virus (VSV)-New Jersey isolates of the 1995 outbreak with those from previous outbreaks between 1982 and 1985 in the western United States. SAMPLE POPULATION: 23 virus isolates considered representative of the 1995 outbreak of vesicular stomatitis. PROCEDURE: Viral gene coding for surface-envelope protein G was evaluated by use of nucleotide sequencing and phylogenetic analysis. RESULTS: Changes in up to 0.77% of the nucleotide bases and 1.35% of the amino acids were detected among the 1995 viral isolates, whereas changes in up to 3.2 and 2.9% of the nucleotides and amino acids, respectively, were found, compared with the 1982 to 1985 viruses. Insertions or deletions were not found in the entire gene, which spanned 1,554 nucleotide bases. CONCLUSIONS AND CLINICAL RELEVANCE: Phylogenetic analysis indicated that the 1995 VSV-New Jersey belongs to a lineage distinct from that of the 1982 to 1985 viruses that caused previous outbreaks in the western United States. Furthermore, it also is distinct from strains from Central America and from the Georgian Hazelhurst strain.     

Effects of dietary carbohydrates and buffering capacity on nutrient digestibility and manure characteristics in finishing pigs

A 2 x 3 factorial experiment was conducted with 24 finishing pigs (Yorkshire x [Finnish Landrace x Dutch Landrace]) to determine the effects of dietary buffering capacity (BC) and carbohydrate sources on apparent total tract digestibility (TD), N retention, and manure characteristics. Twelve of these pigs were fitted with steered ileo-cecal value cannulas to measure the apparent ileal digestibility (ID) of N. Experimental variables were two levels of BC (High = 600 mEq/kg and Low = 530 mEq/kg) and three dietary carbohydrates (tapioca [28%], soybean hulls [25%], and sugar beet pulp [25%]). The two levels of BC were achieved by adjusting the amounts of alkalogenic limestone and acidogenic Ca sulfate in the diet. Pigs were fed twice daily at 2.4 x maintenance requirement for metabolizable energy (418 kJ ME/BW(0.75)). Chromic oxide was used as an indigestible marker. Feces and urine were collected over 5 d for nutrient balance and in vitro measurements of pH and ammonia emission over 7 d. No significant interactions between BC and dietary carbohydrates on the ID, TD, N retention, or manure characteristics were observed. Lowering BC with Ca sulfate did not affect digestibility of most nutrients, except for a negative impact on the TD of Ca (P = 0.015) and Mg (P = 0.003). Although all pigs receiving Ca sulfate had more acidic urine (by 0.49 pH units; P = 0.001), ammonia emission from manure was not lowered, irrespective of the carbohydrate source. Carbohydrates affected significantly the ID and TD of most nutrients, whereas N retention remained similar (P > 0.10). Urinary N:fecal N ratios in manure of pigs fed diets with tapioca, soybean hulls, and beet pulp were 2.09, 1.35, and 1.67, respectively. These ratios corresponded with in vitro ammonia emission (169, 125, and 148 mmol/7 d; P = 0.023). In conclusion, these results indicate that the acidification of urine in pigs fed Ca sulfate in the presence of NSP-rich carbohydrates was achieved. However, acidity of manure and ammonia emission were not affected. The addition of NSP from soybean hulls and(or) sugar beet pulp reduced ratios of urinary:fecal N, and thereby ammonia emission.     

Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH

The effect of active immunization against GnRH on production, carcass, and behavioral traits was examined in ram lambs fed to a uniform slaughter weight. Lambs (initial BW = 32.6+/-1 kg) were stratified by BW and assigned at random to one of four treatment groups (n = 12 lambs/group). Lambs were untreated, castrated, or actively immunized against GnRH using a GnRH-keyhole limpet hemocyanin conjugate (1 mg) emulsified with either Freund's complete adjuvant (FCA) or another oil-based adjuvant (ISA). Animals were housed individually and slaughtered at 58 kg BW. Immunoneutralization of GnRH reduced (P < .05) testes weight and the concentration of testosterone in serum at slaughter. Suppression of testicular size and function was most clearly evident in animals immunized using FCA. Final anti-GnRH titer was also highest in lambs immunized using FCA. Several measures of sexual behavior (frequency of mounts and ejaculations) were also reduced (P < .05) in animals immunized using FCA. The duration of the feeding period was greater (P < .05) for castrated lambs than for untreated lambs, and intermediate feeding periods were required for FCA and ISA lambs. Average daily gain was greater (P < .05) in untreated than in castrated, FCA, or ISA lambs. Similarly, feed efficiency for untreated lambs was greater (P < .05) than for castrated, FCA, or ISA lambs, but feed efficiency did not differ among castrated, FCA, or ISA lambs. Longissimus muscle area, lean and bone maturity, overall quality, muscling score, flank streaking, and color of fat did not differ among treatments. Intact, FCA, and ISA lambs had more (P < .05) desirable yield grades, less (P < .05) backfat, and less (P < .05) marbling than castrated lambs. In summary, immunization against GnRH decreased testicular weight and reduced (P < .05) feedlot performance and sexual behavior to levels comparable to those of castrated males. Partitioning of nutrients for growth and deposition of fat, however, seems to differ among immunologically castrated and physically castrated lambs. This difference in nutrient partitioning may be due to residual testicular activity in immunized lambs.     

The immunogenicity and efficacy of replication-defective and replication-competent bovine adenovirus-3 expressing bovine herpesvirus-1 glycoprotein gD in cattle

Replication-competent and replication-defective bovine adenovirus type 3 recombinants expressing the bovine herpesvirus type 1 (BHV-1) glycoprotein D (gD) were tested for induction of gD specific immune responses in calves using intratracheal (1st and 2nd immunization) and sub-cutaneous (3rd immunization) route of immunization. The replication-defective recombinant BAV501 induced systemic immune responses against gD as low titers of anti gD-IgG were detected in the serum. However, the efficacy of the replication-competent BAV3.E3gD to induce gD-specific antibodies in the serum and the nasal secretions was superior to that of replication-defective BAV501 when both viruses were given at the same dosage. Partial protection from challenge was induced in calves immunized with replication-competent BAV3.E3gD. A dramatic increase in the titers of anti-gD IgG and IgA levels, both in serum and nasal secretions, following BHV-1 challenge (anamnestic response) suggested that the animals immunized with replication-defective BAV501 had been primed for gD-specific antibody responses.