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Neospora caninum plays an important role in abortion and economic losses in dairy industry worldwide. The main target of this work was to detect the infection rate of N. caninum in various hosts in dairy farms for identifying the risk factors and applying appropriate control programs to reduce the number of abortions. The study was conducted in dairy farms with high incidence of abortion in Hamedan province, West of Iran. After the primary assessment, we conducted a controlling program for reducing the Neospora‑infection rate and associated abortions. Before implementing the control program, the seropositivity was 24.8% in cows (N=476 distributed in 10 farms) and 8.6% (N=185) in dogs. Abortion occurred in 3.57% of pregnant cows. 94.1% of aborted cows were positive for Neospora‑infection. Based on molecular technique, the infection rate was detected in 7.3% of cats (N=41), in 25% of pigeons (N=19)and in 11.8% of rodents (N=51). After the implementation of neosporosis control programs in the farms, the seropositivity of N. caninum decreased to 8.2% in cows and 2.9% in dogs. After the one‑year follow‑up, no cases of abortions were reported in the farms. This was the first parallel evaluation of Neospora‑infection and controlling programs in Iranian dairy farms. Regular control of rodents, retesting of seronegative animals and farm biosecurity measures are recommended for reducing the abortion incidence. The access of dogs to the herd and to aborted materials should be restricted.

Bovine trichomonosis is caused by Tritrichomonas foetus. Thirty-three US states have state rules on this disease and render it reportable due to potential huge economic losses to cattle industry. The various rules of different states generally mandate testing and culling T. foetus-positive bulls as well as prohibiting import of T. foetus-positive animals. Wyoming has enforced these rules for over 20 year beginning in 2000. From 2017 to 2019, 3 years in a row, not even one T. foetus-positive bull has been detected throughout the entire state among over ten thousand bulls tested annually. Wyoming is the first US state to achieve total control and eradication of bovine trichomonosis by testing and culling T. foetus-positive bulls., (© 2021. The Author(s).)

Salmonella enterica subsp. enterica serovar Abortusequi is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage P IZ SAE-01E2 against S Abortusequi in a mouse model of abortion were investigated. Phage P IZ SAE-01E2 was stable at different temperatures (4 to 70°C) and pH values (pH 4 to 10) and could lyse the majority of the Salmonella serogroup O:4 and O:9 strains tested (25/28). There was no lysogeny-related, toxin, or antibiotic resistance-related gene in the genome of P IZ SAE-01E2. All of these characteristics indicate that P IZ SAE-01E2 has the potential for use in phage therapy. In in vivo experiments, 2 × 10 3 CFU/mouse of S Abortusequi ATCC 9842 was sufficient to lead to murine abortion (gestational day 14.5) within 48 h. A single intraperitoneal inoculation of P IZ SAE-01E2 (10 8 PFU/mouse, multiplicity of infection = 10 5 ) 1 h before or after S Abortusequi challenge provided effective protection to all pregnant mice (10/10). After 24 h of treatment with phage P IZ SAE-01E2, the bacterial loads in both the placenta and the uterus of the infected mice were significantly decreased (<10 2  CFU/g) compared to those in the placenta and the uterus of the mice in the control group (>10 6  CFU/g). In addition, the levels of inflammatory cytokines in the placenta and blood of the mice in the phage administration groups were significantly reduced ( P <  0.05) compared to those in the placenta and blood of the mice in the control group. Altogether, these findings indicate that P IZ SAE-01E2 shows the potential to block abortions induced by S Abortusequi in vivo IMPORTANCE S Abortusequi is an important pathogen that can induce abortions in mares. Although S Abortusequi has been well controlled in Europe and the United States due to strict breeding and health policies, it is still widespread in African and Asian countries and has proven difficult to control. In China, abortions caused by S Abortusequi have also been reported in donkeys. So far, there is no commercial vaccine. Thus, exploiting alternative efficient and safe strategies to control S Abortusequi infection is essential. In this study, a new lytic phage, P IZ SAE-01E2, infecting S Abortusequi was isolated, and the characteristics of P IZ SAE-01E2 indicated that it has the potential for use in phage therapy. A single intraperitoneal inoculation of P IZ SAE-01E2 before or after S Abortusequi challenge provided effective protection to all pregnant mice. Thus, P IZ SAE-01E2 showed the potential to block abortions induced by S Abortusequi in vivo ., (Copyright © 2020 American Society for Microbiology.)

The objectives of this study were to assess abortion risk (AR) and the number of piglets that died during suckling periods per litter (DP) in farms infected with porcine epidemic diarrhea (PED) in relation to herd immunization procedures. Data were obtained from 91 farms in Japan that had PED infection during 2013 to 2014. The 91 PED-positive farms were asked the number of abortions that occurred and DP for 3 months (1 month before PED outbreak (previous month), 1 month after PED outbreak (the month of PED), and from 1 month after PED outbreak to 2 months after PED outbreak (following month)). AR in each month was calculated as the number of abortions divided by sow inventory. Both AR and DP in the month of PED were higher than those in the previous and following months (p < .05). Farms that performed a herd immunization procedure had higher AR and DP in the month of PED than those that did not perform the procedure (p < .05). In summary, PED occurrence increased AR and DP., (© 2020 Japanese Society of Animal Science.)

Neospora caninum is one of the main causes of abortion in cattle, and recent studies have highlighted its relevance as an abortifacient in small ruminants. Vaccines or drugs for the control of neosporosis are lacking. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models. We here present the pharmacokinetics, safety and efficacy of BKI-1553 in pregnant ewes and foetuses using a pregnant sheep model of N. caninum infection. BKI-1553 showed exposure in pregnant ewes with trough concentrations of approximately 4 μM, and of 1  μM in foetuses. Subcutaneous BKI-1553 administration increased rectal temperatures shortly after treatment, and resulted in dermal nodules triggering a slight monocytosis after repeated doses at short intervals. BKI-1553 treatment decreased fever in infected pregnant ewes already after two applications, resulted in a 37-50% reduction in foetal mortality, and modulated immune responses; IFNγ levels were increased early after infection and IgG levels were reduced subsequently. N. caninum was abundantly found in placental tissues; however, parasite detection in foetal brain tissue decreased from 94% in the infected/untreated group to 69-71% in the treated groups. In summary, BKI-1553 confers partial protection against abortion in a ruminant experimental model of N. caninum infection during pregnancy. In addition, reduced parasite detection, parasite load and lesions in foetal brains were observed., (Copyright © 2018. Published by Elsevier Ltd.)

Epizootic bovine abortion (EBA), or "foothill abortion," is the leading cause of beef cattle abortion in California and has also been reported in Nevada and Oregon. In the 1970s, the soft-shelled tick Ornithodoros coriaceus , or "pajaroello tick," was confirmed as the disease-transmitting vector. In 2005, a novel Deltaproteobacterium was discovered as the etiologic agent of EBA (aoEBA), recently named Pajaroellobacter abortibovis This organism cannot be grown in culture using traditional microbiological techniques; it can only be grown in experimentally-infected severe combined immunodeficient (SCID) mice. The objectives of this study were to perform a de novo genome assembly for P. abortibovis and identify and validate potential antigenic proteins as candidates for future recombinant vaccine development. DNA and RNA were extracted from spleen tissue collected from experimentally-infected SCID mice following exposure to P. abortibovis This combination of mouse and bacterial DNA was sequenced and aligned to the mouse genome. Mouse sequences were subtracted from the sequence pool and the remaining sequences were de novo assembled at 50x coverage into a 1.82 Mbp complete closed circular Deltaproteobacterial genome containing 2250 putative protein-coding sequences. Phylogenetic analysis of P. abortibovis predicts that this bacterium is most closely related to the organisms of the order Myxococcales, referred to as Myxobacteria. In silico prediction of vaccine candidates was performed using a reverse vaccinology approach resulting in the identification and ranking of the top 10 candidate proteins that are likely to be antigenic. Immunologic testing of these candidate proteins confirmed antigenicity of seven of the nine expressed protein candidates using serum from P. abortibovis immunized mice., (Copyright © 2017 Welly et al.)

Brucella abortus vaccines play a central role in bovine brucellosis control/eradication programs and have been successfully used worldwide for decades. Strain 19 and RB51 are the approved B. abortus vaccines strains most commonly used to protect cattle against infection and abortion. However, due to some drawbacks shown by these vaccines much effort has been undertaken for the development of new vaccines, safer and more effective, that could also be used in other susceptible species of animals. In this paper, we present a review of the main aspects of the vaccines that have been used in the brucellosis control over the years and the current research advances in the development of new B. abortus vaccines.

A systematic review of the literature was performed with the objective to evaluate the effects of progesterone supplementation using a single intravaginal insert during timed artificial insemination (AI) programs on fertility in lactating dairy cows. A total of 25 randomized controlled studies including 8,285 supplemented cows and 8,398 untreated controls were included in the meta-analysis. Information regarding the presence of corpus luteum (CL) at the initiation of the synchronization protocol was available for 6,883 supplemented cows and 6,879 untreated controls in 21 experiments. Studies were classified based on service number (first AI vs. resynchronized AI), use of presynchronization (yes vs. no), and insemination of cows in estrus during the synchronization protocol (inseminated in estrus and timed AI vs. timed AI only). Reproductive outcomes of interest were pregnancy per AI (P/AI) measured on d 32 (27 to 42) and 60 (41 to 71) after AI, and pregnancy loss between d 32 and 60 of gestation. Random effects meta-analyses were conducted and treatment effect was summarized into a pooled risk ratio with the Knapp-Hartung modification (RRK+H). The effect of moderator variables was assessed using meta-regression analyses. Progesterone supplementation increased the risk of pregnancy on d 32 [RRK+H = 1.08; 95% confidence interval (CI) = 1.02-1.14] and 60 after AI (RRK+H = 1.10; 95% CI = 1.03-1.17). The benefit of progesterone supplementation was observed mainly in cows lacking a CL at the initiation of the timed AI program (d 60: RRK+H = 1.18; 95% CI = 1.07-1.30) rather than those with CL (d 60: RRK+H = 1.06; 95% CI = 0.99-1.12). Progesterone supplementation benefited P/AI in studies in which all cows were inseminated at timed AI (d 60: RRK+H = 1.20; 95% CI = 1.10-1.29), but not in studies in which cows could be inseminated in estrus during the timed AI program (d 60: RRK+H = 1.04; 95% CI = 0.92-1.16). Progesterone supplementation tended to reduce the risk of pregnancy loss (RRK+H = 0.84; 95% CI = 0.67-1.00). Service number and presynchronization did not influence the effect of progesterone supplementation on fertility. In summary, progesterone supplementation using a single intravaginal insert during the timed AI program increased P/AI mostly in cows without CL and reduced the risk of pregnancy loss in lactating dairy cows. Insemination of cows in estrus during the synchronization protocol eliminated the benefit of supplemental progesterone on P/AI., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The use of live vaccine strain RB51 for vaccination of domestic water buffaloes (Bubalus bubalis) at risk of infection with Brucella abortus is permitted notwithstanding the plans for the eradication and only under strict veterinary control. The antibodies induced by RB51 vaccination are not detectable using conventional diagnostic techniques; therefore, it is necessary to have a specific diagnostic tool able to discriminate vaccinated from unvaccinated animals. The combination of a complement fixation test (CFT) with specific RB51 antigen (RB51-CFT) and a brucellin skin test has been demonstrated to be a reliable diagnostic system to identify single cattle (Bos taurus) vaccinated with RB51. So far, no data are available in the international scientific literature regarding the use of this test association in water buffalo. For this reason the suitability of this test combination has been evaluated in a water buffalo herd. One hundred twenty-seven animals farmed in a herd of Salerno province (Campania, Southern Italy), in the context of a presumptive unauthorized use of RB51 vaccine were chosen for this study. All tested animals resulted negative to Rose Bengal test (RBT) and complement fixation test (CFT) used for the detection of specific antibodies against Brucella field strains. Seventy-one animals (56%) developed RB51 antigen-specific CFT (RB51-CFT) antibodies against RB51 vaccine in a first sampling, while 104 animals (82%) gave positive result to a second serum sampling conducted 11 days after the intradermal inoculation of the RB51 brucellin. One hundred and seven animals (84%) showed a positive reaction to the RB51-CFT in at least 1 sampling, while 111 animals (87%) resulted positive to the RB51 brucellin skin test. Thus, analysing the results of the 3 testing in parallel, 119 animals (94%) were positive to at least 1 of the performed tests. The results suggest that the use in parallel of the RB51 brucellin skin test with RB51-CFT may represent a reliable diagnostic system to identify water buffaloes vaccinated with RB51 vaccine.

Summary: Two outbreaks of Leptospira borgpetersenii serovar Hardjo infection in dairy cattle herds were managed through the application of enhanced biosecurity measures, whole-herd antibiotic treatment and vaccination. Micro-agglutination test antibody titres were determined in paired serum samples at 3 weeks (T1: n = 125, 97% seropositivity, median 800, range 100-12 800) and 24 weeks (T2: n = 110, 88% seropositivity, median 200, range 100-6400) after vaccination and studied in relation to cows' age, herd of origin and sampling time. From T1 to T2, vaccine-elicited antibody titres decreased by 84·7% (95% CI 76·2-90·1). Consistent with increasing immunocompetence in calves (aged <12 months) and immunosenescence in adult cows (aged >36 months) associated with ageing, antibody titres correlated positively with calves' age and negatively with adult cows' age. No cow had cultivable, (histo)pathologically detectable and/or PCR-detectable leptospires in urine or kidney samples after treatment and vaccination. Vaccination together with proper biosecurity measures and chemoprophylaxis are an affordable insurance to control bovine leptospirosis.

Benzo[alpha]pyrene (B[α]P) was used to test the possible antimutagenic effects of Arthrospira (Spirulina) maxima (SP) on male and female mice. SP was orally administered at 0, 200, 400, or 800 mg/kg of body weight to animals of both sexes for 2 weeks before starting the B[α]P (intraperitoneal injection) at 125 mg/kg of body weight for 5 consecutive days. For the male dominant lethal test, each male was caged with two untreated females per week for 3 weeks. For the female dominant lethal test, each female was caged for 1 week with one untreated male. All the females were evaluated 13-15 days after mating for incidence of pregnancy, total corpora lutea, total implants and pre- and postimplant losses. SP protected from B[α]P-induced pre- and postimplant losses in the male dominant lethal test, and from B[α]P-induced postimplantation losses in treated females. Moreover, SP treatment significantly reduced the detrimental effect of B[α]P on the quality of mouse semen. Our results illustrate the protective effects of SP in relation to B[α]P-induced genetic damage to germ cells. We conclude that SP, owing mainly to the presence of phycocyanin, could be of potential clinical interest in cancer treatment or prevention of relapse.

The efficacy of sulfadimidine (4 doses of 33 mg/kg body weight, IM, q48h) against Toxoplasma abortion was assessed in 3 dairy goat herds suffering from Toxoplasma abortions during the 4th month of gestation. This protocol was very effective for the control of Toxoplasma abortions (P < 0.01).

Objective: To determine whether administration of 2 doses of a multivalent, modified-live virus vaccine prior to breeding of heifers would provide protection against abortion and fetal infection following exposure of pregnant heifers to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) and cattle with acute bovine herpesvirus 1 (BHV1) infection., Design: Randomized controlled clinical trial., Animals: 33 crossbred beef heifers, 3 steers, 6 bulls, and 25 calves., Procedures: 20 of 22 vaccinated and 10 of 11 unvaccinated heifers became pregnant and were commingled with 3 steers PI with BVDV type 1a, 1b, or 2 for 56 days beginning 102 days after the second vaccination (administered 30 days after the first vaccination). Eighty days following removal of BVDV-PI steers, heifers were commingled with 3 bulls with acute BHV1 infection for 14 days., Results: After BVDV exposure, 1 fetus (not evaluated) was aborted by a vaccinated heifer; BVDV was detected in 0 of 19 calves from vaccinated heifers and in all 4 fetuses (aborted after BHV1 exposure) and 6 calves from unvaccinated heifers. Bovine herpesvirus 1 was not detected in any fetus or calf and associated fetal membranes in either treatment group. Vaccinated heifers had longer gestation periods and calves with greater birth weights, weaning weights, average daily gains, and market value at weaning, compared with those for calves born to unvaccinated heifers., Conclusions and Clinical Relevance: Prebreeding administration of a modified-live virus vaccine to heifers resulted in fewer abortions and BVDV-PI offspring and improved growth and increased market value of weaned calves.

Serum samples from 376 randomly selected adult cattle, from 25 farms located in 3 counties (Arad, Bihor, and Timiş) from western Romania, were sampled for Neospora caninum antibodies using a commercial ELISA-kit. Seroprevalence values and risk factors for neosporosis (cow age, breed, herd size, farming system, previous abortion, and number of farm dogs) were examined using a generalized linear mixed model with a binomial distribution. Overall, the seroprevalence of N. caninum was 27.7% (104/376) with a prevalence of 27.9% (24/86) in Arad, 26.9% (25/93) in Bihor, and 27.9% (55/197) in Timiş. Of 25 cattle herds, 23 were seropositive with a prevalence ranging from 10.0 to 52.2%. No correlation was found between N. caninum seropositivity and age, breed, herd size, breeding system, and previous abortion. The number of farm dogs was the only factor (P(Wald)  =  0.03) positively associated with seroprevalence in cows and can be considered the risk factor in the acquiring of infection. The present work is the first regarding serological evidence of N. caninum infection in cattle from western Romania.

To avoid the problems associated with twinning in dairy cattle, one of the embryos may be eliminated. This study compares the effect on pregnancy maintenance of two embryo reduction techniques, manual rupture (MR) and transvaginal ultrasound-guided aspiration (TUGA) of allanto-amniotic fluid, in Holstein-Friesian cows with multiple pregnancies. In the first experiment, 61 lactating cows bearing unilateral twins (n=27), bilateral twins (n=30) or triplets/quadruplets (n=4) were subjected to MR (n=45) or TUGA using a 17-G neddle (n=16) on day 28-34 of gestation. In 21 and 10 cows undergoing MR and TUGA embryo reduction, respectively, pregnancy loss occurred before day 90 (46.7 vs. 62.5%, P= 0.28). Through binary logistic regression, the type of pregnancy was identified as the only variable significantly affecting pregnancy maintenance (P=0.03). Based on the odds ratio, the risk of pregnancy loss was 4.1 times higher for unilateral twins than for bilateral twins (70.4 vs. 36.7%, respectively, P=0.01). No effect was detected on pregnancy maintenance of the technique used (P=0.17) or of the interaction technique by type of pregnancy (P=0.22). In the second experiment, a 22-G needle was used to perform TUGA on 22 lactating cows. The pregnancy loss rates were 44.4% (4/9), 18.2% (2/11) and 50% (1/2) for cows bearing unilateral twins, bilateral twins and triplets, respectively. The total pregnancy loss rate following TUGA using the 22-G needle tended to be lower than that using the 17-G needle (31.8 vs. 62.5%; P=0.06). Our results suggest that TUGA using a 22-G needle could be the method of choice to perform embryo reduction in cows carrying multiple pregnancies.

Objective: To determine the effect of palpation per rectum (PPR) by use of 1 or 2 fetal membrane slips (FMSs) for pregnancy diagnosis during early gestation on pregnancy loss in dairy cattle., Design: Controlled, randomized block design., Animals: 928 healthy pregnant cattle., Procedures: All cattle were determined to be pregnant by use of transrectal ultrasonography at approximately day 31 after estrus and randomly allocated into 2 groups (control group [n = 476 cows] and palpation group [452]). The control group was not subjected to pregnancy diagnosis via PPR. The palpation group was subdivided into 2 groups (PPR FMS 1 [n = 230 cows] and PPR FMS 2 [222]), which involved PPR and pregnancy diagnosis via 1 or 2 FMSs, respectively, during the same examination, which was performed by 1 veterinarian between days 34 and 43 after estrus. All cattle were reevaluated by use of transrectal ultrasonography on days 45 and 60 to determine viability of the embryo and fetus, respectively., Results: Overall pregnancy loss between days 31 and 60 was 14.1%. Pregnancy loss for the control, PPR FMS 1, and PPR FMS 2 groups from days 31 to 60 was 14.5%, 12.6%, and 14.9%, respectively. Embryonic pregnancy loss for the control, PPR FMS 1, and PPR FMS 2 groups was 12.4%, 9.1%, and 9.5%, respectively. Fetal pregnancy loss for the same groups was 2.4%, 3.8%, and 5.9%, respectively., Conclusions and Clinical Relevance: Pregnancy diagnosis via 1 or 2 FMSs performed during PPR in early gestation did not increase pregnancy loss in dairy cattle.

Objective: To compare efficacy of 2 commercial ovine Campylobacter vaccines and an experimental bacterin in guinea pigs following IP inoculation with Campylobacter jejuni IA3902., Animals: 51 female guinea pigs., Procedures: Pregnant and nonpregnant animals were randomly assigned to 1 of 4 treatment groups and administered a commercial Campylobacter vaccine labeled for prevention of campylobacteriosis in sheep via two 5-mL doses 14 days apart (vaccine A; n = 13), another labeled for prevention of campylobacteriosis via two 2-mL doses (vaccine B; 12), an experimental bacterin prepared from the challenge strain (12), or a sham vaccine (14). Ten days later, animals were challenged IP with C jejuni IA3902; 48 hours later, animals were euthanized, complete necropsy was performed, and blood and tissue samples were obtained for bacteriologic culture., Results: Administration of vaccine B or the experimental bacterin, but not vaccine A, significantly reduced 48-hour infection rates versus administration of the sham vaccine. A significantly reduced 48-hour infection rate was associated with administration of vaccine B independent of pregnancy status., Conclusions and Clinical Relevance: Administration of vaccine B significantly reduced infection in guinea pigs challenged with C jejuni IA3902, similar to a homologous bacterin. Results suggested that vaccine B or an autogenous product may be effective in controlling ovine campylobacteriosis caused by this emergent abortifacient strain. Bacteriologic culture of blood, liver, bile, and uterus in nonpregnant guinea pigs 48 hours after inoculation may be a useful screening tool for comparing efficacy of C jejuni vaccines.

Q fever is a worldwide zoonosis caused by the bacterium Coxiella burnetii. The control of this infection in cattle is crucial: infected ruminants can indeed encounter reproductive disorders and represent the most important source of human infection. In the field, vaccination is currently advised in infected herds but the comparative effectiveness of different vaccination protocols has never been explored: the duration of the vaccination programme and the category of animals to be vaccinated have to be determined. Our objective was to compare, by simulation, the effectiveness over 10 years of three different vaccination strategies in a recently infected dairy cattle herd.A stochastic individual-based epidemic model coupled with a model of herd demography was developed to simulate three temporal outputs (shedder prevalence, environmental bacterial load and number of abortions) and to calculate the extinction rate of the infection. For all strategies, the temporal outputs were predicted to strongly decrease with time at least in the first years of vaccination. However, vaccinating only three years was predicted inadequate to stabilize these dynamic outputs at a low level. Vaccination of both cows and heifers was predicted as being slightly more effective than vaccinating heifers only. Although the simulated extinction rate of the infection was high for both scenarios, the outputs decreased slower when only heifers were vaccinated.Our findings shed new light on vaccination effectiveness related to Q fever. Moreover, the model can be further modified for simulating and assessing various Q fever control strategies such as environmental and hygienic measures.

Calving records from the Animal Breeding Center of Iran collected from January 1983 to December 2007 and comprising 1,163,594 Holstein calving events from 2552 herds were used to evaluate the potential effect of abortion occurrence on 305-day milk yield, milk fat yield, fat percentage of milk and milk protein yield in Iranian Holsteins. Statistical analyses of production traits were performed using a linear mixed model procedure. Normal-calved cows had greater 305-day milk production, fat yield and protein yield of milk than abortive-calved cows (P < 0.05). However, abortive-calved cows had the greater milk fat percentage than normal calved cows (P < 0.05). The linear and quadratic effects of age of dam were significant on all of the studied traits (P < 0.05). The results of regression analysis showed that increase in the quadratic effect of age can cause an increase in the fat percentage of milk for all calvings including normal and abortive calvings. Because abortion is one of the most important conditions that limit a cow's ability to produce, maintaining the general health of cattle is important in minimizing the risk of abortion problems., (© 2010 The Authors. Journal compilation © 2010 Japanese Society of Animal Science.)

This study assessed the effectiveness of a mutant strain of Toxoplasma gondii (RH strain) lacking the mic1 and mic3 genes (Mic1-3KO) against Toxoplasma abortion in sheep. Ewes were inoculated subcutaneously with 10(5) Mic1-3KO tachyzoïtes in three independent experiments. Following vaccination, Mic1-3KO induced a mild febrile response and serum IgG antibodies, which persisted throughout the experiments. Tissue cysts formed in the sheep, but were not, under our experimental conditions, infectious when given orally. Ewes were mated two months after vaccination and were orally challenged with the PRU strain of T. gondii at mid-gestation (400 oocysts in Experiments 1 and 2; 100 oocysts in Experiment 3). Challenge of vaccinated pregnant ewes resulted in a slight febrile response, whereas unvaccinated ewes developed a more severe, characteristic febrile response of longer duration. After challenge, all unvaccinated ewes aborted whereas 62%, 91% and 64% (Experiments 1, 2 and 3 respectively) of the lambs from vaccinated ewes were viable, with no clinical signs of infection. Mic1-3KO was as effective as S48, the strain used as a live vaccine for sheep (Toxovax). A dose of 10(5) Mic1-3KO tachyzoites was sufficient to induce protection (versus a dose of 2x10(6)). Both subcutaneous and intraperitoneal injections were effective. Moreover, preliminary results showed the potential of Mic1-3KO to reduce the development of tissue cysts in lambs born to vaccinated ewes. This study demonstrates that Mic1-3KO is a potent vaccine candidate., (Copyright (c) INRA, EDP Sciences, 2010.)

Region IV of phase 1 flagellin (FliC) of Salmonella enterica serovar Brandenburg (S. Brandenburg) was expressed in Escherichia coli and purified by nickel chelate affinity chromatography. The purified recombinant protein was evaluated for its suitability as an antigen in an indirect ELISA for the detection of antibodies in sheep sera. A cut-off value of 0.1 was calculated using 80 serum samples collected from sheep with no previous history of S. Brandenburg. In the present study we show the results of ELISA with field sera collected from 81 sheep naturally infected with S. Brandenburg. The assay was able to detect antibodies belonging to the IgG class with a sensitivity of 93.8 %. Thus, indirect ELISA might be a suitable screening tool for serological monitoring of sheep flocks infected with S. Brandenburg.

Brucellosis is an important zoonotic disease of nearly worldwide distribution. The occurrence of the infection in humans is largely dependent on the prevalence of brucellosis in animal reservoirs, including wildlife. The current vaccine used for cattle Brucella abortus strain RB51, has proven ineffective in protecting bison (Bison bison) and elk (Cervus nelsoni) from infection and abortion. To test possible improvements in vaccine efficacy, a novel approach of immunization was examined from April 2004 to November 2006 using alginate composite microspheres containing a nonimmunogenic, eggshell-precursor protein of the parasite Fasciola hepatica (Vitelline protein B, VpB) to deliver live vaccine strain RB51. Red deer (Cervus elaphus), used as a model for elk, were vaccinated orally (PO) or subcutaneously (SC) with 1.5x10(10) viable organisms per animal. Humoral responses postvaccination (immunoglobulin G [IgG] levels), assessed at different time points, indicated that capsules containing live RB51 elicited an anti-Brucella specific IgG response. Furthermore, the encapsulated vaccine elicited a cell-mediated response that the nonencapsulated vaccinates failed to produce. Finally, red deer were challenged with B. abortus strain 19 by conjunctival exposure. Only animals that received encapsulated RB51 vaccine by either route exhibited a significant reduction in bacterial counts in their spleens. These data suggest that alginate-VpB microspheres provide a method to enhance the RB51 vaccine performance in elk.

Objective: To evaluate the efficacy of an inactivated bovine herpesvirus-1 (BHV-1) vaccine to protect against BHV-1 challenge-induced abortion and stillbirth., Design: Prospective study., Animals: 35 beef heifers., Procedures: Before breeding, heifers were vaccinated with a commercially available BHV-1 inactivated vaccine SC or IM. The estrous cycle was then synchronized, and heifers were artificially inseminated 30 to 60 days after vaccination. Heifers (n = 21) were challenge inoculated IV at approximately 180 days of gestation with virulent BHV-1. Fourteen control heifers were not vaccinated. Clinical signs of BHV-1 infection were monitored for 10 days following challenge; serologic status and occurrence of abortion or stillbirth were evaluated until time of calving., Results: 18 of 21 (85.7%) heifers that received vaccine were protected from abortion following challenge, whereas all 14 control heifers aborted., Conclusions and Clinical Relevance: Results indicated that an inactivated BHV-1 vaccine can protect against abortion resulting from a substantial challenge infection, with efficacy similar to that of modified-live BHV-1 vaccines.

Neospora caninum is a protozoan parasite of animals. Until 1988, it was misidentified as Toxoplasma gondii. Since its first recognition in dogs in 1984 and the description of the new genus and species Neospora caninum in 1988, neosporosis has emerged as a serious disease of cattle and dogs worldwide. Abortions and neonatal mortality are a major problem in livestock operations, and neosporosis is a major cause of abortion in cattle. Although antibodies to N. caninum have been reported, the parasite has not been detected in human tissues. Thus, the zoonotic potential is uncertain. This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated. The role of wildlife in the life cycle of N. caninum and strategies for the control of neosporosis in cattle are discussed.

Objective: To determine the immunogenicity and efficacy of Brucella abortus strain RB51 (SRB51) as a vaccine in domestic pigs., Animals: Sixty-eight 6-week-old crossbred domestic pigs and twenty-four 4-month-old gilts., Procedures: In experiment 1, pigs were vaccinated IM (n = 51) with 2 x 10(10) CFUs of SRB51 or sham inoculated (17). Periodic blood samples were obtained to perform blood cultures, serologic evaluations, and cell-mediated immunity assays. Necropsies were performed at selected times between weeks 1 and 23 after vaccination to determine vaccine clearance. In experiment 2, gilts were similarly vaccinated (n = 18) or sham inoculated (8) and similar samples were obtained after vaccination. Gilts were bred and challenged conjunctivally with 5.0 x 10(7) CFUs of virulent Brucella suis strain 3B. Necropsies were performed on gilts and on fetuses or neonates after abortion or parturition, respectively. Bacterial cultures and serologic evaluations were performed on samples obtained at necropsy to determine vaccine efficacy., Results: Humoral and cell-mediated immune responses did not differ between vaccinates and controls. After vaccination, SRB51 was not isolated from blood cultures of either group and was isolated from lymphoid tissues of 3 pigs at 2 weeks (n = 2) and 4 weeks (1) after vaccination. No differences were found in isolation of B suis or in seroconversion between vaccinated and control gilts and between their neonates or aborted fetuses., Conclusions and Clinical Relevance: Parenteral vaccination with SRB51 does not induce humoral or cell-mediated immune responses. Vaccination with SRB51 did not protect gilts or their neonates and fetuses from virulent challenge with B suis.

The objectives were to determine if a diet enriched in alpha-linolenic acid (ALA) would influence ovarian function, early embryo survival, conception rates, and pregnancy losses in lactating dairy cows. Beginning 28 d before breeding, Holstein cows (55 +/- 22 d postpartum; mean +/- SD) were assigned to diets supplemented with either rolled flaxseed (FLAX; 56.7% ALA, n = 62) or rolled sunflower seed (SUNF; 0.1% ALA, n = 59) to provide approximately 750 g of oil/d. Diets continued for 32 d after timed artificial insemination (TAI, d 0) following a Presynch/Ovsynch protocol. Barley silage- and barley grain-based TMR were formulated to meet or exceed National Research Council requirements. Metabolizable protein and net energy for lactation concentrations were similar in the 2 diets. Based upon a mean dry matter intake of 22 kg/d, cows fed FLAX or SUNF consumed > 410 g or < 1 g of ALA, respectively. Pregnancy was confirmed by ultrasound 32 d after TAI. Nonpregnant cows were placed on a second Ovsynch regimen and reinseminated 42 d after first TAI, and received oilseeds for 32 d after second TAI. Relative to prediet levels, FLAX increased the ALA content of milk by 187%. Ovarian ultrasonography was performed in 8 cows per diet; the mean diameter of ovulatory follicles was larger in cows fed FLAX compared with SUNF (16.9 +/- 0.9 vs. 14.1 +/- 0.9 mm), but follicle number, corpus luteum size, and plasma progesterone concentrations remained unaffected. Presumptive conception (progesterone < 1 ng/mL on d 0 and > 1 ng/mL on d 21) rates to first TAI were greater in FLAX than in SUNF (72.6 vs. 47.5%). Pregnancy losses were lower in cows fed FLAX (9.8%) compared with those fed SUNF (27.3%). Including flaxseed in the ration of dairy cows increased the size of the ovulatory follicle and reduced pregnancy losses.

Avidity serological tests (avidity enzyme-linked immunosorbent assay [ELISA] and avidity Western blot) were developed and used to differentiate between acute (primary infection, reinfection, and recrudescence) and chronic Neospora caninum infection in cattle. In addition, the pattern of immunoglobulin G (IgG) avidity maturation against different specific antigens of N. caninum tachyzoites was studied. Sequential serum samples were collected from cattle naturally and experimentally infected with N. caninum. Four groups of experimentally infected cattle were included in the study and were representative of primary infection, reinfection, chronic infection, and noninfection. Serum samples were also collected from naturally infected cattle classified into nonaborting and aborting cows on the basis of clinical findings and serological profiles, and a third group composed of seronegative cows that seroconverted during the course of the experiment. All samples were tested by avidity ELISA and avidity Western blot. The IgG avidity ELISA allowed the discrimination between primary and chronic infection because all experimentally primary-infection cows showed low avidity indexes at week 4 postinfection (p.i.) compared with the high avidity values found at week 20 postinfection. However, this test did not allow the discrimination of reinfection or recrudescence from chronic infection. Regarding IgG avidity Western blot results, no antigenic markers correlating with acute (primary infection, recrudescence, and reinfection) or chronic infection were recognized. However, the 17-kD immunodominant antigen was mostly responsible for high avidity values obtained by avidity ELISA because it was intensively recognized by high-avidity antibodies in all chronically infected animals after urea treatment.

Three live vaccine candidates of Salmonella enterica subspecies I serotype Abortusovis (aroA, cya crp cdt, and plasmid-cured strains) have been developed, and their efficacies in inducing humoral antibodies and protecting against abortion after challenge with wild-type strain SS44 were evaluated in sheep. Following estrus synchronization, animals were immunized 3 weeks after fertilization and boosted once 3 weeks later. Following challenge with wild-type SS44, pregnancy failure of vaccinated ewes was reduced compared to that of nonimmunized controls. Attenuation of each vaccine was also assessed in challenge experiments with nonimmunized pregnant ewes and in BALB/c mice. All three vaccine candidates appear to be safe for use in sheep and provide a model for the development of live vaccine candidates against naturally occurring ovine salmonellosis.

Objective: To identify potential risk factors for embryonic loss before 35 to 42 days of gestation in dairy cattle., Design: Prospective observational study., Animals: 381 cows., Procedure: Body condition score was determined at the time of artificial insemination (AI; day 0) and on days 20, 23, and 27 and between days 35 and 41; serum progesterone concentration was measured on days 0; 20 or 21; and 23, 24, or 25. Cows were excluded from analyses if day 0 serum progesterone concentration was > or = 1.0 ng/mL and classified as pregnant on day 23 if serum progesterone was > 1.5 ng/mL on day 20 or 21 and day 23, 24, or 25. Cows were examined via transrectal ultrasonography on day 27 or 28 and rectally palpated for pregnancy on days 35 to 41., Results: 39% of cows that were pregnant on day 23 lost their embryo by day 27, and 18% of cows that were pregnant on day 27 or 28 were not pregnant on days 35 to 41. Breeding a pregnant cow posed the greatest risk for embryonic loss at both time periods. Mean serum progesterone concentrations on day 21 or 22 and day 23, 24, or 25 were lowest for cows that lost an embryo between days 24 and 28. Cows with a linear somatic cell count score > 4.5 before AI were twice as likely to lose the embryo by 35 to 41 days, compared with cows with a score < 4.5., Conclusions and Clinical Relevance: Results suggest that embryonic loss could be reduced by more accurate estrus detection, reducing mastitis, and strategies to improve progesterone concentration after breeding.

Objective: To evaluate the efficacy of a modified-live virus (MLV) combination vaccine containing type 1 and type 2 bovine viral diarrhea virus (BVDV) in providing fetal protection against challenge with heterologous type 1 and type 2 BVDV., Design: Prospective study., Animals: 55 heifers., Procedure: Heifers were vaccinated with a commercial MLV combination vaccine or given a sham vaccine (sterile water) and bred 47 to 53 days later. Heifers were challenged with type 1 or type 2 BVDV on days 75 to 79 of gestation. Clinical signs of BVDV infection, presence of viremia, and WBC count were assessed for 14 days after challenge. Fetuses were collected on days 152 to 156 of gestation, and virus isolation was attempted from fetal tissues., Results: Type 1 BVDV was not isolated in any fetuses from vaccinated heifers and was isolated in all fetuses from nonvaccinated heifers challenged with type 1 BVDV. Type 2 BVDV was isolated in 1 fetus from a vaccinated heifer and all fetuses from nonvaccinated heifers challenged with type 2 BVDV., Conclusions and Clinical Relevance: A commercial MLV combination vaccine containing type 1 and type 2 BVDV given to the dam prior to breeding protected 100% of fetuses against type 1 BVDV infection and 95% of fetuses against type 2 BVDV infection. Use of a bivalent MLV vaccine in combination with a comprehensive BVDV control program should result in decreased incidence of persistent infection in calves and therefore minimize the risk of BVDV infection in the herd.

Preventing pregnancy in brucellosis-infected bison (Bison bison) provides a potential means of preventing transmission of disease. To determine whether a gonadotropin-releasing hormone (GnRH) vaccine was effective in reducing pregnancy in bison and to study the safety of injecting GnRH in pregnant bison, a study was conducted at the Idaho Fish and Game Wildlife Health Laboratory in Caldwell, Idaho (USA). Four pregnant and two nonpregnant female bison were given a single injection of GnRH vaccine, and five pregnant adult females were given a sham injection that contained only adjuvant. Three of the GnRH-vaccinated bison that were pregnant at the time of vaccination delivered healthy calves. One treated bison had dystocia that resulted in a dead calf. All control bison delivered healthy calves. After calving, females of both groups were exposed to two bulls. Treated bison were palpated 6 wk after exposure to the bulls, and blood was drawn for pregnancy-specific protein B analysis. The six treated bison were not pregnant. The sham-treated bison became pregnant and delivered viable calves. This study demonstrates that a single dose of GnRH vaccine is effective in preventing pregnancy in female bison for at least 1 yr.

Objective: To compare economic outcome for herds not exposed to Neospora caninum with that for herds with various seroprevalences of N caninum infection and evaluate 3 control strategies., Design: Economic simulation model., Sample Population: Beef herds with various seroprevalences of N caninum infection., Procedure: A 5-year simulation model was used. Control strategies that were evaluated included culling females that fail to calve, selling seropositive females and purchasing seronegative replacements, and excluding the daughters of seropositive dams as potential replacements., Results: For a 5-year period with low prices for feeder calves, endemic N caninum infection decreased mean return to fixed assets by 22.2% when true seroprevalence was 10% and by 29.9% when true seroprevalence was 70%. Percentage decrease in return to fixed assets was less dramatic when a 5-year period with high prices for feeder calves was evaluated. Analysis indicated that 2 control strategies (culling females that fail to give birth to a calf and selling seropositive female cattle and purchasing seronegative replacement female cattle) were not likely to be economically beneficial. The third control strategy (testing the entire herd for N caninum infection and excluding the female offspring of seropositive dams as replacements) appeared to be a reasonable control strategy., Conclusions and Clinical Relevance: For the assumptions in the model, endemic N caninum infection decreases return to fixed assets for cow-calf herds. Of the potential control strategies evaluated, testing the entire herd for N caninum infection and excluding the daughters of seropositive dams as potential replacements provided the best economic return.)

From December 1998 through February 1999, a study was conducted in a Brucella-infected bison herd to evaluate the safety of booster vaccination of adult bison (Bison bison) with 6 x 10(9) colony forming units (CFU) of Brucella abortus strain RB51 (SRB51) that had previously been vaccinated as yearlings with 1 x 10(10) CFU of SRB51. Abortions or other adverse effects were not observed after SRB51 booster vaccination. At 10 wk after adult vaccination, pregnant and nonpregnant bison (n = 65) were randomly selected for bacteriologic sampling of targeted maternal tissues during abattoir processing. Fetal tissues were also sampled in pregnant bison. The SR351 recovered from tissue samples of eight of 48 pregnant bison and none of 17 nonpregnant bison. In three of the eight culture-positive bison, SRB51 was recovered from fetal tissues. In three additional bison, one pregnant and two nonpregnant, B. abortus biovar 1 field strain was recovered from internal iliac or supramammary lymphatic tissues. Results of this study suggest the possibility that the SRB51 vaccine can be safely used to booster vaccinate pregnant bison in a Brucella-infected bison herd. Our data also reaffirms the potential for B. abortus field strains to persist in bison until attainment of reproductive age, despite extensive use of vaccination and serologic testing.

Surface layer proteins (SLPs) are essential for induction of abortion by Campylobacter fetus subsp. fetus in experimentally challenged ewes. These proteins are encoded by multiple sap genes and vary in size and antigenicity. The role of SLP antigenic variation during experimental ovine infection was investigated. Following subcutaneous challenge, the SLPs were highly antigenic, and antibodies were detected in serum, milk, bile, and urine. Fecal anti-SLP antibodies were detected only in animals challenged orally. Ewes challenged with wild-type strain 23D with variable SLPs developed detectable circulating anti-SLP immunoglobulin G (IgG) antibodies by 2 weeks postchallenge. In contrast, ewes challenged with mutants of 23D that had fixed expression of a single SLP developed antibodies within 1 week postchallenge, suggesting that antigenic variation in SLPs may delay the host antibody response. Although not statistically significant, the data from challenge experiments in which vaccinated ewes were used suggested that SLP-expressing vaccines could protect animals from abortion and that this effect was independent of the SLP expressed, indicating involvement of conserved epitopes in the SLP. The conserved 184-amino-acid N-terminal region of the SLP, identified from previously published sequences, was epitope mapped with rabbit anti-SLP antisera by using overlapping synthetic 20-mer peptides. Two putative epitopes were identified at amino acids 81 to 110 and 141 to 160. Amino acids 81 to 100 also bound serum IgG antibodies from experimentally challenged sheep. Conserved antigenic regions of the SLP that induce protective immune responses may enable development of synthetic vaccine candidates for C. fetus subsp. fetus-associated ovine abortion.

Brucella abortus strain RB51 is used as a vaccine because it induces antibodies that do not react on standard serologic tests for brucellosis allowing differentiation between vaccination and infection. Strain RB51 was evaluated in captive elk (Cervus elaphus) to determine if vaccination protected against abortion following experimental challenge. Thirty elk were vaccinated intramuscularly with 1.0 x 10(10) colony-forming units (CFU) of strain RB51 in March 1998. Fourteen of these were given a booster dose of 1.13 x 10(10) CFU exactly 1 yr later. All vaccinated elk seroconverted via a modified dot blot assay to strain RB51 with the booster group having higher titers (P < or = 0.001). Seventeen other elk served as unvaccinated controls. All elk were bred and determined pregnant using pregnancy-specific protein B analysis. Elk were challenged in March 2000 with 1.1 x 10(7) CFU of B. abortus strain 2308 administered intraconjunctivally and all elk seroconverted to strain 2308. Fifteen of 17 control elk aborted; 16 of 16 elk given a single vaccination aborted (P = 0.44); and 13 of 14 elk given a booster aborted (P = 0.86). There were two viable calves in the control group and one in the booster group. Strain 2308 was recovered from fetuses and nonviable calves in all groups. Based on the results of this and other studies, the use of strain RB51 to prevent abortion in elk cannot be recommended.

Bovine brucellosis is a serious zoonotic disease affecting some populations of Rocky Mountain elk (Cervus elaphus nelsoni) and bison (Bison bison) in the Greater Yellowstone Area, USA. The fear that elk and/or bison may spread Brucella abortus to livestock has prompted efforts to reduce or eliminate the disease in wildlife. Brucella abortus strain RB51 (RB51) vaccine has recently been approved for use in cattle. Unlike strain 19 vaccine, RB51 does not cause false positive reactions on standard brucellosis serologic tests. If effective, it may become the vaccine of choice for wildlife. In February 1995, 45 serologically negative female elk calves were trapped and taken to the Sybille Wildlife Research and Conservation Education Unit near Wheatland, Wyoming, USA. In May 1995, 16 of these elk calves were hand-vaccinated with 1 x 10(9) colony forming units (CFU) of RB51, 16 were vaccinated with 1 x 10(8) CFU RB51 by biobullet, and 13 were given a saline placebo. The elk were bred in fall of 1996 and they were challenged with 1 x 10(7) CFU of B. abortus strain 2308 by intraconjunctival inoculation in March 1997. Thirteen (100%) control elk aborted, 14 (88%) hand-vaccinated elk aborted, and 12 (75%) biobullet vaccinated elk aborted or produced nonviable calves. These results suggest that a single dose of 1 x 10(8) to 1 x 10(9) CFU RB51 does not provide significant protection against B. abortus induced abortion in elk. However, the vaccine appears to be safe at this dose and additional study may reveal a more effective RB51 vaccine regimen for elk.

Brucella abortus strain RB51 is a laboratory-derived rough mutant of virulent B. abortus strain 2308 used as a vaccine because it induces antibodies that do not react on standard brucellosis serologic tests. Strain RB51 vaccine was evaluated in pregnant captive elk (Cervus elaphus) to determine (1) if it induced abortion and (2) if it protected against abortion following subsequent challenge. The time period of this study (February-June, 1998) was similar to field conditions where elk are vaccinated and possibly exposed to B. abortus. Fourteen elk were randomly and equally divided into vaccinated and control groups. The vaccinated group was vaccinated intramuscularly with 1.03 x 10(10) colony-forming units (CFU) of strain RB51 and seroconverted postvaccination. Antibodies to strain RB51 were detected by a modification of an existing dot-blot assay. Both groups were challenged 40 days postvaccination with 9.8 x 10(6) CFU of B. abortus strain 2308 administered intraconjunctivally. The first abortion occurred 38 days postchallenge. Abortion occurred in all control elk and in five of seven vaccinated elk 5 to 12 wk postchallenge (P = 0.23). Mixed strain RB51 and 2308 infections were present in fetuses and vaginas from the vaccinated group whereas only strain 2308 was cultured from control group fetuses and vaginal swabs. Further evaluation of strain RB51 will be necessary to determine if it will be safe and efficacious in free-ranging pregnant elk.

Fecal progestagen analysis in okapis (Okapia johnstoni) was used for diagnosis of pregnancy and reproductive disorders, including a comparison of urinary and fecal progestagen analysis and endocrine data on the postpartum period. Data were generated on reliability of fecal progestagen analysis in early pregnancy diagnosis, and case reports were compiled involving single animals with missing luteal activity, abortion after twin pregnancy, and abortions due to deficient placental progestagen production. There was approximately 100-200-fold higher progestagen concentration in feces than in urine, thus explaining the high reliability of fecal progestagen evaluations in diagnosing luteal function and pregnancy. The postpartum period was characterized by lactational anestrus of several months duration, and a postpartum estrous cycle about 2-3 wk after parturition was observed in two of eight animals. An animal with five abortions due to deficient placental progestagen production was treated with altrenogest in a subsequent pregnancy and carried the fetus to term.

Treatment of pregnant mares to prevent abortions due to equine piroplasmosis is a novel idea practised empirically at some Thoroughbred studs in South Africa. This paper presents the results of an investigation to ascertain whether imidocarb dipropionate crosses the equine placenta. Three pregnant mares were injected intramuscularly with imidocarb and their foetuses were mechanically aborted at varying time intervals thereafter. Imidocarb was found in foetal blood at a level similar to that in the dam's blood, suggesting that imidocarb administered to the dam would be available for anti-parasitic activity in the foetal circulation. Uncertainty concerning the time of treatment to achieve the desired effect currently makes this a questionable exercise.

Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming systems in South Africa are described. On 2 farms, pigs constituted the main enterprise with cattle and sheep of secondary importance. On each of these 2 farms, abortion due to L. pomona in sows was confirmed by culture, and antibody titres to pomona were detected in cattle, sheep, horses and dogs. On the 3rd farm, a piggery was of secondary importance to cattle farming. Abortion and death in cows occurred on this farm and serology showed titres to various serovars, including pomona. L. pomona was also isolated from bovine urine, an aborted bovine foetus and kidneys from slaughtered pigs. This particular case study was regarded as clinically atypical in that adult Jersey cattle died of acute leptospirosis in a semiarid region of South Africa. In all 3 case studies, the poor management of pig effluent and of the drinking water and its sources played a pivotal role in the transmission of the disease. Inadequate vaccination of animals against Leptospira and poor record-keeping within the secondary farming enterprises were also contributing factors to the spread of leptospirosis.

To determine the safety of Brucella abortus strain RB51 (SRB51) vaccine in American bison (Bison bison), 31 animals from a herd with brucellosis were used. In October 1996, 10 adult bison males and seven calves were vaccinated with the standard calfhood cattle dose of 1.8 x 10(10) colony forming units (CFU) of SRB51 subcutaneously while the adult females received the standard adult cattle dose of 1 x 10(9) CFU. Western immunoblot indicated the presence of SRB51 antibodies following vaccination. To evaluate prolonged bacterial colonization of tissues, the adult males, calves, and three adult females were divided into two groups which were slaughtered at either 13 or 16 wk post-vaccination. At necropsy, tissue samples were obtained for B. abortus culture from the liver, spleen, lymph nodes, and reproductive tract of each animal. While B. abortus field strain was cultured from one adult bull, no SRB51 was isolated from any of the animals. Seven pregnant females were monitored until parturition for signs of abortions and fetal lesions. Six cows delivered healthy calves and one delivered a dead full-term calf that was brucellae negative. Based on these results, administration of SRB51 to bison did not cause prolonged bacterial colonization of tissues in calves, adult males, or adult females. Furthermore, SRB51 did not induce abortions following vaccination in the second month of gestation.

A pseudorabies virus (PRV) glycoprotein-mixed vaccine was prepared by heparin-affinity chromatography from PRV-infected PK-15 cell lysates. In our previous study, the trial vaccine was induced protection with suppression of virus shedding in one-month-old pigs and generation of cytotoxic T lymphocyte (CTL) response in mice. In this study, the effect of the trial vaccine on suppression of both virus shedding and reproductive failure in pregnant sows was examined. Three sows were vaccinated twice until one week before mating. Each of them was infected intranasally with 10(6) TCID50 of PRV on day 28, 54, or 85 after mating, respectively. Three other sows were also mated and challenged at the same time as the respective control. The vaccinated sows produced virus-neutralizing antibodies. Sows with high level of VN antibody lowered the level and period of virus shedding after challenge. The maximum level of shed-virus titers in vaccinated sows were 10(1.25) to 10(3) times lower than controls. Vaccinated sows shed virus for 1 or 5 days, while controls shed for 8, 9, or 12 days. No abortion or stillbirth was observed in vaccinated sows during pregnancy. On the other hand, control sow challenged at a late stage of pregnancy showed abortion and stillbirth. The results obtained here indicate that our trial vaccine is effective to prevent reproductive failure by pseudorabies virus.

A series of mutants of equine herpesvirus-1 (EHV-1) which contain deletions in non-essential genes was previously characterized in a murine intranasal infection model. One mutant, ED71 which was shown to be attenuated in the model, was further characterized by inoculation into pregnant mice. Despite the attenuation previously reported, intranasal inoculation of pregnant mice resulted in premature parturition and the birth of dead or dying foetuses. Furthermore, mice inoculated before pregnancy with the same mutant, and subsequently challenged 14 days after conception with wild-type virus, were not protected from abortion.

To determine the placental tropism and abortigenicity of the vaccine candidate Brucella abortus strain RB51 (SRB51), a rough mutant of the virulent strain 2308, ten Polled Hereford heifers were inoculated intravenously in the 6th month of gestation. Heifers were euthanatized and examined at postinoculation week (PIW) 8 (n = 5) or at full term (n = 5). Four of five infected heifers sampled at PIW 8 and three of four infected heifers at term had placentitis, whereas reproductive tissues of three normal cows used for comparison had no placentitis. Numerous macrophages, immunoreactive for SRB51 antigen, as well as neutrophils, fibrin, and cell debris filled the arcade zone between chorion and maternal septae. Trophoblastic epithelium of the placentomal arcade zone had intracellular bacteria that were immunoreactive for SRB51 antigen. The tips of maternal septa had a lymphoplasmacytic infiltrate with small multifocal erosions and ulcerations of maternal epithelium. SRB51 was cultured from all tissues in which lesions were seen. Placentae of one cow from each group had no placentitis and contained no SRB51. In mammae, interstitial lymphoplasmacytic infiltrates and suppurative infiltrates within alveoli and intralobular ductules were seen in two of five heifers at PIW 8. SRB51 was cultured from liver, spleen, lung, and bronchial lymph nodes in four of five calves at PIW 8 and three of four full-term calves, but no lesions were seen. One near-term heifer had disseminated infection, placentitis, and lymphoplasmacytic endometritis, and delivered a premature weak calf. These results establish that SRB51 is less abortifacient than previously published reports with strain 19, in that only one of four heifers delivered prematurely following intravenous inoculation with SRB51, whereas intravenous inoculation with strain 19 leads to 100% abortion. However, it also shows that SRB51 can infect the bovine placenta, mammary gland, and fetus, can induce placentitis, and, in some cases, can lead to preterm expulsion of the fetus.

Objective: To evaluate the efficacy of a commercially available temperature-sensitive modified-live bovine herpesvirus type-1 (BHV-1) vaccine against BHV-1 challenge-induced abortion and stillbirth., Design: Prospective randomized control trial., Animals: 20 cycling, nonpregnant, BHV-1 seronegative heifers of various breeds and weights, 12 to 15 months old., Procedure: Heifers were randomly assigned to a vaccinate (n = 10) or nonvaccinate control (n = 10) group. Seventeen to 26 days after members of the vaccinate group received a second dose of vaccine, all heifers were artificially inseminated. Heifers were challenged intravenously with Cooper strain BHV-1 between days 177 and 187 of gestation. Aborted fetuses and stillborn calves were necropsied, and tissues collected for histologic examination and virus isolation. Heifers, calves, and fetuses were tested for BHV-1 antibody throughout the study., Results: The difference in number of abortions or stillbirths between vaccinated heifers (1/10) and control heifers (10/10) was significant (P < 0.003). Seven of 10 control heifers had a virus neutralization antibody titer to BHV-1 at abortion or stillbirth that declined or remained unchanged from their titer at a previous serologic evaluation (7 to 66 days earlier)., Clinical Implications: Prebreeding vaccination of replacement heifers with modified-live BHV-1 vaccine provides fetal protection at 6 months of gestation (7 months after vaccination) and appears to be a reasonable precaution to control economic losses associated with BHV-1 infection. Abortions induced by BHV-1 are not necessarily associated with rising or markedly high virus neutralization antibody titers. These titers should be used cautiously when assessing the role of BHV-1 in bovine abortion and stillbirth.

Monoclonal antibodies (MAbs) were generated against an ovine abortive strain of Chlamydia psittaci. A plaque reduction assay was used to select 19 neutralizing antibodies which appeared to be heterogeneous in isotype, specificity, and recognized proteins. Different neutralizing MAbs were tested for their protective abilities against abortion in a pregnant-mouse model. All of the protective MAbs selected had the same isotype, were serotype 1 specific, and recognized a protein of about 110 kDa by immunoblotting. The recognized epitopes were resistant to sodium dodecyl sulfate and reducing agents, but all of them were heat sensitive. The protein was able to form disulfide-linked polymers. Immunological cross-reaction studies with rabbit sera showed a link between the 110-kDa protein and the major outer membrane protein (MOMP). The 110-kDa protein was purified by immunoaffinity and shown to be dissociated after heating into MOMP by silver staining and immunoblotting. These results show homogeneity among protective MAbs directed to heat-sensitive epitopes located on an oligomer of the MOMP of C. psittaci.