Effect of glycerin on immediate cutaneous reactions of histamine (positive) and phosphate-buffered saline (negative) controls in intradermal skin testing of healthy dogs: A randomised, blinded study.

BACKGROUND: Glycerinated allergen extracts contain 50% glycerin, an excellent preservative. While glycerin is a recognised irritant in humans, the utility of glycerinated extracts for intradermal testing has not been validated in dogs. HYPOTHESIS/OBJECTIVE: To determine and compare the effects of glycerin on immediate cutaneous reactions to intradermal injections of histamine and saline in healthy dogs. ANIMALS: Eight healthy laboratory beagles. MATERIALS AND METHODS: The study was designed as a randomised, blinded study. Intradermal injections of histamine (positive control) and saline (negative control) in aqueous and glycerinated (50%) forms were performed on the right thorax. Global wheal scores (GWS) at 20 min were evaluated by two independent investigators blinded to the interventions. RESULTS: There were no wheal and flare reactions observed after the intradermal injections of phenolated saline. By contrast, 50% glycerosaline injections induced erythema and induration in all dogs. Global wheal scores were significantly higher in aqueous histamine (Friedman test, p < 0.0001) and 50% glycerinated histamine (Friedman test, p = 0.0084) compared to phenolated saline controls. Interestingly, only aqueous histamine (Friedman test, p = 0.01) had significantly higher GWS than 50% glycerosaline injections, while no significant difference in GWS between 50% glycerinated histamine and 50% glycerosaline groups was observed (Friedman test, p = 0.59). CONCLUSION AND CLINICAL RELEVANCE: This study demonstrates that intradermal injection of 50% glycerosaline induces erythema and induration skin reactions in healthy dogs that can mimic positive reactions to allergenic extracts. Further dilutions of glycerinated positive and negative control solutions need to be optimised for intradermal testing in dogs.

Antibody response to rabies pre-exposure vaccination among village health volunteers in a northern region of Thailand.

BACKGROUND: Rabies is a lethal, however the disease is preventable through vaccination either before or immediately after an exposure. This study aimed to provide a pre-exposure prophylaxis rabies immunization to village health volunteers (VHV) who provide rabies vaccination for pets and free-roaming dogs in their villages and evaluate the antibody level and adverse effects after vaccination. We also assessed the knowledge related to rabies of these VHVs before field trip for pet vaccination. METHODS: This study was conducted at Mae Kha sub district, San Pa Tong district, Chiangmai, Thailand between January and March 2020. Consenting participants were interviewed using a questionnaire, received an intradermal two-dose, seven-day pre-exposure rabies vaccination, and sera were tested for anti-rabies antibody levels with the cost effective easy competitive enzyme-linked immunosorbent assay (CEE-cELISA) before and after vaccination. RESULTS: A total of 27 VHVs were recruited from 14 villages in Mae Kha sub district. All of them were male and had a median age of 61.5 years (interquartile range: 55-64). After vaccination, seroconversion rate was 92 % (23/25) with a median of 12.4 EU/mL (interquartile range: 8.9-20.1). Two participants who had rabies vaccination one year previously still had adequate levels before receiving a booster dose. All participants did not show any serious adverse reactions after vaccination. CONCLUSION: A regimen of two-dose, seven-day vaccination series in high-risk health volunteers using an intradermal administration provides a high seroconversion rate, efficacy and safe for pre-exposure vaccination schedule. In addition, rabies-related knowledge should be provided to village health volunteers before their fieldwork.

Intradermal co-inoculation of codon pair deoptimization (CPD)-attenuated chimeric porcine reproductive and respiratory syndrome virus (PRRSV) with Toll like receptor (TLR) agonists enhanced the protective effects in pigs against heterologous challenge.

The objective of this study was to assess protective efficacy of vaccination using CPD-attenuated chimeric PRRSV and Toll like receptor (TLR) agonists (HSP70 c-terminal domain and HSPX) as adjuvants through different inoculation routes. In this study, a chimeric PRRSV composed of two field isolates was synthesized and attenuated by CPD in NSP1 as described in the previous study. The infection of the CPD-attenuated chimeric PRRSV to pigs of 3 weeks-old showed no clinical signs without pathological lesions in necropsy, while it induced improved cross immunity between its parent strains. The TLR agonists were expressed in E. coli and purified to be used. In challenge experiment, pigs of 3 weeks-old were vaccinated using the CPD-attenuated chimeric virus with the prepared TLR agonists through intramuscular or intradermal route, following heterologous challenge after 4 weeks of vaccination. In results, intramuscular or intradermal inoculation of the CPD-attenuated chimeric virus demonstrated excellent protective efficacy against heterologous challenges. Importantly, intradermal inoculation with the TLR agonists enhanced protective effects as shown in the significantly increased level of PRRSV-specific IFN-γ-SCs and cytokines in sera, and the significant reduction of pathological lesion and viral load in lung. This study suggested that the intradermal inoculation of CPD-attenuated chimeric PRRSV plus TLR agonists should be more effective for protection of pigs against diverse PRRS field viruses.

Comparison of antibody titres between intradermal and intramuscular rabies vaccination using inactivated vaccine in cattle in Bhutan.

In developing countries, the cost of vaccination limits the use of prophylactic rabies vaccination, especially in cattle. Intradermal vaccination delivers antigen directly to an area with higher number of antigen-presenting cells. Therefore, it could produce equivalent or higher antibody titres than conventional intramuscular vaccination even when a lower dose is given. This study aimed to compare the antibody response in cattle vaccinated intramuscularly with 1mL of inactivated rabies vaccine (Raksharab, Indian Immunologicals) against intradermally vaccinated cattle with 0.2mL of the same vaccine. The study was conducted in Haa province of Bhutan where rabies is not endemic. One hundred cattle from 27 farms were selected for the study. Virus neutralising antibody (VNA) response was measured using the fluorescent antibody virus neutralisation test on the day of vaccination (day 0) and 14, 30, 60 and 90 days later. Overall, 71% of intradermally vaccinated cattle and 89% of the intramuscularly vaccinated cattle produced an adequate response (≥0.5IU/mL). On days 14 and 30 post vaccination fewer cattle (P<0.02) in the intradermal group had adequate titres with 36% and 58%, respectively, having titres ≥0.5 IU/mL compared to the equivalent figures of 78% and 77% in the intramuscular group. The mean VNA titres were lower for the intradermal group than intramuscular group (p<0.001) with the mean difference being > 0.6 IU/mL. Although low dose intradermal vaccination did produce a detectable antibody response, it was inferior to intramuscular vaccination. Thus, although intradermal vaccination has the potential to reduce the cost of vaccination by reducing the dose required, this study showed that a single dose of 0.2 mL intradermally was inferior to an intramuscular dose of 1 mL. Further research evaluating dose and dose regimen is needed before intradermal vaccination using the Raksharab rabies vaccine can be recommended in cattle.

Delayed type hypersensitivity induced by intradermal inoculation of a Neospora caninum tachyzoite antigen in previously exposed cattle.

The aim of this study was to evaluate delayed type hypersensitivity (DTH) induced by the intradermal inoculation of a Neospora caninum tachyzoite soluble lysate in cattle previously exposed with the protozoa. Four experimental groups were selected according to the prior exposure to N. caninum antigen. All cows were intradermally injected with a N. caninum tachyzoite soluble lysate and skinfold thickness growth at the inoculation sites was measured at 0, 24, 48, 72 and 96 h post inoculation (hpi). Additionally, specific antibodies and IFN-γ production were assessed. Cows experimentally infected with live N. caninum tachyzoites and cows naturally exposed to N. caninum developed skin reactions compatible with DTH between 24 and 96 hpi (p < 0.05). Moreover, cows inoculated with an experimental N. caninum vaccine and cows without evidence of exposure to N. caninum did not show a significant increase in skin thickness (p > 0.05). Furthermore, serological status of the animals was not modified due to the intradermal inoculation. The highest IFN-γ production was observed at 15 days after intradermal inoculation (p < 0.05). Therefore, these results suggest that cattle previously exposed to N. caninum develop a reaction compatible with DTH which could be useful as in vivo cell mediated immunity parameter for assessed bovine neosporosis.

Safety and immune responses after intradermal application of Porcilis PRRS in either the neck or the perianal region.

The objective of the present study was to assess safety and immune responses in gilts after intradermal application of Porcilis® PRRS in two different application sites under field conditions. Forty-four gilts were allocated to one of three groups: Gilts of group 1 (n = 10) served as non-vaccinated controls, gilts of group 2 (n = 17) were vaccinated intradermally in the neck and gilts of group 3 (n = 17) received an intradermal vaccination in the perianal region. Clinical observations, local injection site reactions and histopathologic examination of the injection site were used for safety assessments. Frequency and degree of clinical signs were not significantly different between all three groups. Minor local reactions for both vaccination groups were observed; however, at 6, 7, 8, 9 and 15 days post-vaccination (dpv), the mean injection site reaction score was significantly lower in pigs vaccinated in the perianal region. In histopathologic examination, an extended inflammatory dimension was observed more frequently in pigs vaccinated in the neck. Blood samples were analyzed to quantify the post-vaccination humoral (ELISA and virus neutralization test) and cellular (IFN-γ ELISPOT) immune responses. PRRSV-specific antibodies were present in the serum of all vaccinated animals from 14 dpv onwards, whereas all control pigs remained negative throughout the study. Neutralizing antibody titers were significantly higher in pigs vaccinated in the perianal region at 28 dpv. At 14, 21 and 28 dpv, PRRSV-specific IFN-γ secreting cells were significantly increased in both vaccination groups compared to non-vaccinated gilts. Analysis of mean numbers of PRRSV-specific IFN-γ secreting cells did not result in statistically significant differences between both vaccination groups. The results of this study indicate that the perianal region is a safe alternative application site for intradermal vaccination of gilts with Porcilis PRRS. Furthermore, the intradermal application of Porcilis PRRS induced humoral and cellular immune responses independent of the administration site.

CD4+ T cells dominate the leukocyte infiltration response initiated by intra-dermal injection of phytohemagglutinin into growing feathers in chickens.

Phytohemagglutinin (PHA) is commonly used to evaluate cell-mediated immunocompetence. In chickens, PHA is typically injected intra-dermally (i.d.) into the skin (e.g., wing web, wattle, or footpad), and the tissue swelling response is monitored, whereby the extent of tissue swelling positively relates to the individual's cell-mediated immune system capabilities. Although i.d. injected PHA was shown to stimulate mononuclear cell and basophil infiltration to the site of injection, reports on temporal, qualitative, and quantitative aspects of the local cutaneous PHA response are limited. The objective of this study was to use the growing feather (GF) as a cutaneous test site to assess and monitor the type and relative amounts of leukocytes present in the pulp of PHA-injected GF. For this study, male, non-vaccinated Light-brown Leghorn chickens reared at the Arkansas Experiment Station Poultry Health Laboratory were used. At 9 wk of age, the dermis of 20 18-day-old regenerating GF was injected with 10 µL of either PBS diluent or 300 µg/mL PHA-P (5 chickens per treatment). GF were collected from each chicken before (zero) and at 0.25, 1, 2, 3, 4, 5, and 7 d post injection. At each time point, one GF was collected for immunofluorescent staining of pulp cell suspensions and leukocyte population analysis by flow cytometry, and another GF for histological analysis. Histological analysis confirmed participation of granulocytes and mononuclear cells, primarily lymphocytes, in the cutaneous PHA response. As revealed by flow cytometric cell population analysis, T cells, especially CD4+ T cells, constituted the major portion of the mononuclear cell infiltrate. Levels of CD4+ T cells were greatly elevated in PHA-injected GF within 6 h and remained elevated throughout the 7-day examination period. γδ T cells, CD8+ T cells, and B cells also infiltrated in response to PHA although at lower levels and with different time-course patterns from CD4+ T cells. The dominant presence of CD4+ T cells at the site of PHA injection further affirms this polyclonal response as an indicator of cell-mediated immunity.

Field study on the safety and efficacy of intradermal versus intramuscular vaccination against Mycoplasma hyopneumoniae.

The present study compares the safety and efficacy of a needle-free, intradermal Mycoplasma hyopneumoniae vaccine to an intramuscular one. 420 piglets (21+3 days of age) were randomly assigned to two vaccination groups (intradermal vaccination V1 (n=138), intramuscular vaccination V2 (n=144)) and one unvaccinated control group (CG, n=138). As safety parameters clinical observations, local injection site reactions (ISR) and rectal temperatures were assessed. Average daily weight gain (ADWG) and pneumonic lung lesions (LL) were measured as efficacy parameters. ISRs were minor in V1. After both vaccinations, no adverse impact on appetite was observed and mean rectal temperatures remained within physiological range. ADWG during the fattening period was significantly higher in vaccinated groups (V1: 913.4 g, V2: 924.5 g) compared with CG (875.6 g). No differences in ADWG were observed between V1 and V2. Vaccinated pigs had a significantly reduced mean extent of LL compared with CG. V1 was superior in reducing the extent and prevalence of LL compared with V2. These results reveal that a needle-free intradermal vaccination is safe and efficacious in reducing both the prevalence and extent of lung lesions, as well as in improving performance parameters, in a farrow-to-finish farm with a late onset of M hyopneumoniae infection.

Examination of toxicity and collagen linearity after the administration of the protein cross-linker genipin in equine tendon and dermis: a pilot study.

OBJECTIVE: Collagen cross-linking is an attractive therapeutic route aimed at supplementing natural collagen stabilisation. In this study the toxicity of the cross-linker genipin (GP) was examined in avascular (tendon) and vascular (dermis) tissue. METHODS: High doses of GP were injected intratendinously into three yearling horses and evaluated at various time points up to 30 days. A second group of three yearlings were injected into the dermis and evaluated at various time points up to 1 year. Metrics used included lameness, circumferential swelling, ultrasound evaluation, microscopic morphology, collagen production and systemic effect on blood parameters. RESULTS: The tendon injection sites exhibited mild lameness and swelling with no apparent systemic toxicity or stabilisation defects. Treated tendons exhibited increased linear collagen microscopically. Dermal injections showed similar results, with mild swelling at the injection site. Microscopic morphology resulted in a decrease in dermal collagen at 30 days post-injection. Dermis injected at the high dose of 355 mmol/L examined 1 year post-treatment appeared similar to the untreated biopsies; however, there was an increase in mature collagen. CONCLUSION: GP injection appeared to be well tolerated, with transient lameness and mild circumferential swelling when injected into the tendon and local tissue swelling when injected into the dermis. No systemic hypersensitivities or toxicities were observed. Microscopically, GP resulted in increased linear collagen in tendons at 30 days post-injection and overall increased collagen in dermal tissue when evaluated 1 year post-injection.

Three Different Routes of Inoculation for Experimental Infection with Schmallenberg Virus in Sheep.

Schmallenberg virus (SBV) is an emerging Orthobunyavirus affecting European domestic ruminants. In this study, three groups of ewes (n = 3) were inoculated with 1 ml of an SBV infectious serum, via the subcutaneous (SC), intradermal (ID) or intranasal (IN) route. The ewes were monitored for 10 days and no clinical signs were reported. IN inoculation failed to generate any detectable RNAemia. SC and ID inoculation induced typical SBV RNAemia and seroconversion upon day 6 post-inoculation in 3/3 and 2/3 sheep, respectively. In all the animals that showed RNAemia, the viral genome could be detected in spleen and mesenteric lymph nodes. Both the SC and ID routes seem suitable to properly reproduce field conditions, as comparable observations were reported regarding RNAemia, seroconversion and viral genome detection in organs.

Skin Vaccination against Rotavirus Using Microneedles: Proof of Concept in Gnotobiotic Piglets.

Live-attenuated oral rotavirus (RV) vaccines have lower efficacy in low income countries, and additionally are associated with a rare but severe adverse event, intussusception. We have been pursuing the development of an inactivated rotavirus vaccine (IRV) using the human rotavirus strain CDC-9 (G1P[8]) through parenteral immunization and previously demonstrated dose sparing and enhanced immunogenicity of intradermal (ID) unadjuvanted IRV using a coated microneedle patch in comparison with intramuscular (IM) administration in mice. The aim of this study was to evaluate the immune response and protection against RV infection and diarrhea conferred by the administration of the ID unadjuvanted IRV using the microneedle device MicronJet600® in neonatal gnotobiotic (Gn) piglets challenged with virulent Wa G1P[8] human RV. Three doses of 5 µg IRV when administered intradermally and 5 µg IRV formulated with aluminum hydroxide [Al(OH)3] when administered intramuscularly induced comparable rotavirus-specific antibody titers of IgA, IgG, IgG avidity index and neutralizing activity in sera of neonatal piglets. Both IRV vaccination regimens protected against RV antigen shedding in stools, and reduced the cumulative diarrhea scores in the piglets. This study demonstrated that the ID and IM administrations of IRV are immunogenic and protective against RV-induced diarrhea in neonatal piglets. Our findings highlight the potential value of an adjuvant sparing effect of the IRV ID delivery route.

Influence of glucocorticoids on a time-of-day-dependent variation in intradermal reactivity to histamine in dogs.

The objectives of this study were to determine daily variation in intradermal reactivity to histamine in dogs and to evaluate a potential influence of glucocorticoids on reactivity. Wheal sizes formed after intradermal injections of histamine were measured every 6 h during a single 24 h period in six healthy dogs. To determine whether glucocorticoids were implicated in daily variation, intradermal reactivity to histamine was evaluated at 9:00 h and at 21:00 h during a single day in dogs that received oral prednisolone (a synthetic glucocorticoid) or oral trilostane (an inhibitor of endogenous glucocorticoid synthesis). Finally, the time required for the histamine reaction to diminish after an intravenous injection of hydrocortisone was also assessed. A significant time-of-day-dependent variation in intradermal reactivity to histamine was detected in dogs, with a larger wheal size observed at 9:00 h than at 21:00 h. Administration of prednisolone or trilostane disrupted this variation. Intradermal reactivity to histamine was significantly reduced 6 h after an intravenous injection of hydrocortisone. These results suggest that glucocorticoid secretion from the adrenal glands could be involved in the regulation of daily variation in histamine-mediated reactions in dogs.

Characterization of IgE-mediated cutaneous immediate and late-phase reactions in nonallergic horses.

OBJECTIVE: To characterize the response of skin of nonallergic horses following ID injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit IgG. ANIMALS: 6 healthy horses. PROCEDURES: Skin in the cervical area was injected ID with anti-IgE and IgG. Wheal measurements and skin biopsy specimens were obtained before and 20 minutes and 6, 24, and 48 hours after injection. Tissue sections were evaluated for inflammatory cells at 4 dermal depths. Immunohistochemical analysis for CD3, CD4, and CD8 was performed, and cell counts were evaluated. RESULTS: Anti-IgE wheals were significantly larger than IgG wheals at 20 minutes and 6 and 24 hours after injection. There were significantly more degranulated mast cells after anti-IgE injection than after IgG injection. There were significantly more eosinophils at 6, 24, and 48 hours and neutrophils at 6 hours after anti-IgE injection, compared with cell numbers at those same times after IgG injection. There were significantly more eosinophils in the deeper dermis of anti-IgE samples, compared with results for IgG samples. No significant differences between treatments were detected for CD3(+), CD4(+), or CD8(+) cells. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of anti-IgE antibodies was associated with the development of gross and microscopic inflammation characterized by mast cell degranulation and accumulation of inflammatory cells, particularly eosinophils and neutrophils. This pattern appeared to be similar to that of horses with naturally developing allergic skin disease, although lymphocytes were not increased; thus, ID injection of anti-IgE in horses may be of use for evaluating allergic skin diseases of horses.

A study for characterization of IgE-mediated cutaneous immediate and late-phase reactions in non-allergic domestic cats.

Immunoglobulin-E (IgE) mediated reactions can be induced by intradermal injection of anti-IgE antibodies in both humans and dogs. These reactions grossly and histologically mimic changes seen in naturally occurring allergic dermatitis in these species. Similar studies have not been conducted in the cat. Purified polyclonal rabbit-origin IgG specific for canine IgE (anti-IgE) and rabbit immunoglobulin G (IgG) were injected intradermally in 7 non-allergic laboratory colony cats. Wheal measurements were obtained and biopsies collected before injection and at injection sites after 20 min, 6, 24, and 48 h. Injection of anti-IgE induced an immediate wheal response which was significantly larger than that seen after injection of rabbit IgG. Anti-IgE injected skin was also significantly thicker than IgG-injected skin. This corresponded with a significant increase in number of visibly degranulated mast cells in anti-IgE samples when compared to IgG samples. Injection of anti-IgE was associated with the rapid recruitment of inflammatory cells to the injected dermis. The number of inflammatory cells and mononuclear cells were significantly elevated after the injection of anti-IgE when compared to IgG-injected skin. Both eosinophils and neutrophils were significantly increased in anti-IgE samples relative to IgG, although neutrophils were only transiently increased. The high eosinophil and relatively low neutrophil cell counts in these samples were consistent with previously documented histologic features of naturally occurring feline allergic skin disease. Immunohistochemistry identified a significantly overall increased CD1a(+) cells after the intradermal injection of anti-IgE when compared to IgG and non-injected skin. CD3(+), CD8(+) and CD4(+) were also significantly increased overall in anti-IgE injected skin relative to IgG injected skin. These data document the gross and cellular response to injection of anti-IgE in the skin of healthy, non-allergic cats and support a possible role for IgE in the development of feline allergic dermatitis.

Effects of pentoxifylline on immediate and late-phase cutaneous reactions in response to anti-immunoglobulin E antibodies in clinically normal dogs.

OBJECTIVE: To characterize the effects of pentoxifylline on the gross and microscopic variables associated with immediate and late-phase inflammation following injection of IgE-specific antibodies in the skin of clinically normal dogs. ANIMALS: 6 healthy adult mixed-breed dogs. PROCEDURES: Intradermal injections (0.1 mL each) of PBS solution, histamine phosphate, and cross-linking rabbit-origin anti-canine IgE antibodies (3 injections/dog) were administered at 0 hours on day 0; wheal sizes were evaluated at 20 minutes, 6 hours, and 24 hours. Biopsy specimens of injected and noninjected skin were collected 24 hours after injection. On day 2, treatment with pentoxifylline (20 mg/kg, PO, q 8 h) was initiated and continued until day 30. For each dog, injection, measurement, and biopsy procedures were repeated on days 30 to 31 and on days 37 to 38 (ie, after discontinuation of pentoxifylline administration). RESULTS: Pentoxifylline administration was associated with a significant decrease in wheal size at 6 and 24 hours (but not at 20 minutes) after injection of anti-canine IgE. Repeated injections performed 1 week after drug discontinuation revealed partial recovery of the 6-hour cutaneous reaction and complete recovery of the 24-hour cutaneous reaction. Pentoxifylline administration was also associated with inhibition of mast cell degranulation and significant decreases in the total numbers of cutaneous inflammatory cells and eosinophils, compared with pretreatment findings. CONCLUSIONS AND CLINICAL RELEVANCE: In clinically normal dogs, pentoxifylline effectively impaired late-phase reactions but not immediate reactions at sites of intradermal injection of IgE-specific antibodies by inhibiting mast cell degranulation and recruitment of cutaneous inflammatory cells, especially eosinophils.

Effects of adjuvants on the immune response of pigs after intradermal administration of antigen.

The ability of different adjuvants to enhance immune responses to intradermal (ID) immunisation with a model antigen was studied in pigs. Immune responses were evaluated with respect to the intensity of systemic and mucosal antibody formation, their isotype characterisation and rate of cell-mediated immunity. These findings were compared with the intensity of adverse local reactions. Six groups of piglets were immunised with keyhole limpet haemocyanin (KLH) antigen alone or in combination with aluminium hydroxide or selected oil-based adjuvants (complete and incomplete Freund's adjuvants, Montanide ISA 206 and Emulsigen). Systemic specific antibody responses were significantly increased following ID administration of antigen together with any of the adjuvants used. IgG antibody responses were most pronounced after the first administration of antigen, being stimulated with both Freund's and Montanide ISA 206 adjuvants. The oil adjuvants also enhanced the cell-mediated immune responses and the levels of local IgA antibodies in the respiratory mucosa. On the other hand, they elicited more pronounced adverse local reactions.

House finches (Carpodacus mexicanus) balance investment in behavioural and immunological defences against pathogens.

Infection with parasites and pathogens is costly for hosts, causing loss of nutritional resources, reproductive potential, tissue integrity and even life. In response, animals have evolved behavioural and immunological strategies to avoid infection by pathogens and infestation by parasites. Scientists generally study these strategies in isolation from each other; however, since these defences entail costs, host individuals should benefit from balancing investment in these strategies, and understanding of infectious disease dynamics would benefit from studying the relationship between them. Here, we show that Carpodacus mexicanus (house finches) avoid sick individuals. Moreover, we show that individuals investing less in behavioural defences invest more in immune defences. Such variation has important implications for the dynamics of pathogen spread through populations, and ultimately the course of epidemics. A deeper understanding of individual- and population-level disease defence strategies will improve our ability to understand, model and predict the outcomes of pathogen spread in wildlife.

Effects of intratumoral administration of a hyaluronan-cisplatin nanoconjugate to five dogs with soft tissue sarcomas.

OBJECTIVE: To determine the effects of intratumoral injection of a hyaluronan-cisplatin nanoconjugate on local and systemic platinum concentrations and systemic toxicosis. ANIMALS: 5 dogs with spontaneous soft tissue sarcomas (STSs). PROCEDURES: For each dog, approximately 1.5 mL of hyaluronan nanocarrier conjugated with 20 mg of cisplatin was injected into an external STS. Blood samples were collected immediately before (0 hours) and at 0.5, 1, 2, 3, 4, 24, and 96 hours after hyaluronan-cisplatin injection for pharmacokinetic analyses. Urine samples were obtained at 0 and at 96 hours after hyaluronan-cisplatin injection for urinalysis. Each treated STS and its sentinel lymph nodes were surgically removed 96 hours after the hyaluronan-cisplatin injection. Inductively coupled plasma mass spectrometry was used to measure platinum concentrations in blood samples, tumors, and lymph nodes. RESULTS: No tissue reactions were detected 96 hours after hyaluronan-cisplatin injection. Mean ± SD area under the curve, peak concentration, and terminal half-life for unbound (plasma) and total (serum) platinum were 774.6 ± 221.1 ng•h/mL and 3,562.1 ± 2,031.1 ng•h/mL, 56.5 ± 20.9 ng/mL and 81.6 ± 40.4 ng/mL, and 33.6 ± 16.1 hours and 51.2 ± 29.1 hours, respectively. Platinum concentrations ranged from 3,325 to 8,229 ng/g in STSs and 130 to 6,066 ng/g in STS-associated lymph nodes. CONCLUSIONS AND CLINICAL RELEVANCE: Intratumoral injection of the hyaluronan-cisplatin nanoconjugate was well tolerated in treated dogs. Following intratumoral hyaluronan-cisplatin injection, platinum concentration was 1,000-fold and 100-fold greater within treated tumors and tumor-draining lymphatics, respectively, compared with that in plasma.

Loxoribine pretreatment reduces Salmonella Enteritidis organ invasion in 1-day-old chickens.

Young poultry exhibit a transient colonization by some food-borne pathogens, including Salmonella, during the first week of life that stems from immature innate and acquired defense mechanisms. Consequently, modulation of the hosts' natural immune response is emerging as an important area of interest for food animal producers, including the poultry industry. Toll-like receptor (TLR) agonists have been shown to boost the innate immune response in young chickens and increase their resistance to colonization by Salmonella enterica serovar Enteritidis. The objective of the present study was to determine if pretreatment with loxoribine, a TLR7 agonist and immune modulator, protects young chicks from Salmonella Enteritidis organ invasion. Loxoribine (0-100 µg) was administered intra-abdominally to 1-d-old broiler chicks, and 4 h later, the birds were challenged orally with Salmonella Enteritidis. Twenty-four hours postchallenge, birds were euthanized and the liver and spleen aseptically removed and cultured for Salmonella Enteritidis. This was carried out on 3 separate occasions using 26 to 50 chicks per dose per experiment. Pretreatment of chicks with loxoribine (6.25-25 µg) significantly (P ≤ 0.05) reduced liver and spleen organ invasion by Salmonella Enteritidis. Higher doses (50-100 µg) of loxoribine had no effect. The results obtained in this study indicate that there is a potential application for using loxoribine to increase protection of young chicks when they are most susceptible to infections with Salmonella.

Clinical evaluation of intradermal vaccination against porcine enzootic pneumonia (Mycoplasma hyopneumoniae).

The aim of the present study was to investigate the efficacy of single-dose intradermal vaccination against Mycoplasma hyopneumoniae on a commercial swine unit. A total of 1051 healthy suckling piglets of 28±3 days of age were randomly assigned to one of three experimental groups: (a) intradermal: 346 piglets vaccinated intradermally (Porcilis M Hyo ID Once, Intervet SPAH), (b) intramuscular : 351 piglets vaccinated intramuscularly (Porcilis M1 Intervet SPAH) and (c) controls: 354 piglets injected with a placebo (adjuvant only). Performance parameters such as average daily weight gain (ADG), as well as health parameters and lung lesion scores were monitored from four weeks of age until slaughter. The improvement in ADG over the controls, during the finishing phase, was 27 g/day for the intradermal group and 17 g/day for the intramuscular group. Both intradermal and intramuscular vaccinations were effective in reducing clinical signs and lung lesions caused by M hyopneumoniae. Compared with the controls, approximately 10.4 per cent fewer clinical cases were diagnosed in the intradermal group, and 6 per cent fewer in the intramuscular group, during the finishing period. In conclusion, performance results were better in the vaccinated groups than in the control group, while intradermal vaccination afforded greater protection than intramuscular vaccination, especially with regard to morbidity, lung lesion and pleuritis scores.