Bartley P

Moredun Research Institute, Penicuik, Scotland, United Kingdom

Are you Bartley P?

Claim your profile

Publications (56)70.36 Total impact

  • Source
  • Source
  • Source
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluates the influence of immunizing lambs with the incomplete S48 strain of Toxoplasma gondii, on parasite dissemination following a live oral challenge with a complete strain of T. gondii (M4). Lambs were culled at 14, 28 and 42 days post challenge. Parasite DNA was detected at significantly (p < 0.0001) lower levels in samples from the vaccinated/challenged group (0% in heart and 5.9% in skeletal muscles), when compared to the non-vaccinated/challenged animals (75% heart, 87.9% skeletal muscle). S48 T. gondii DNA was found in muscle or lymph nodes until 42 days post infection, suggesting that parasite DNA or tachyzoites could persist longer after immunization than previously thought. Non-vaccinated/challenged animals showed more frequent lesions in muscles and central nervous system than the vaccinated animals. These results demonstrate that vaccination of lambs with the incomplete S48 T. gondii strain, can protect against establishment of tissue cysts following challenge with a complete strain of T. gondii. Consumption of undercooked meat containing T. gondii cysts is a major route of transmission to people, therefore vaccination of food animals may improve the safety of meat for human consumption.
    Veterinary Parasitology 07/2014; DOI:10.1016/j.vetpar.2014.07.003 · 2.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neospora caninum is recognized as a major cause of reproductive losses worldwide but its pathogenesis is not completely understood. Immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to the adverse effects of exacerbated Th1 type response at the maternal-foetal interface. Different clinical outcomes are known to occur following experimental infections of cattle at different stages of gestation, with foetal death being the most common finding during early gestation, and the birth of live congenitally infected calves following infection later in gestation. The aim of the current study was to characterize the cytokine expression in the placenta of cattle experimentally challenged with tachyzoites of the Nc-1 strain during early, mid and late gestation. Moderate to severe infiltration of IL-12, IFN-γ and TNF-α expressing cells was observed in the placentas collected at early gestation and this infiltration was more pronounced in the samples collected from challenged dams carrying non-viable foetuses, compared with the mothers carrying viable foetuses. In contrast, the infiltration of Th1 cytokine expressing-cells was mild following N. caninum infection in mid gestation and scarce during infection in late gestation. Scarce expression of IL-4 was observed in the placentas from N. caninum-challenged and negative control animals throughout gestation. The milder Th1 immune response observed during later stages of gestation following Nc-1 infection could partially explain the less severe clinical outcome when compared to early pregnancy.
    Veterinary Immunology and Immunopathology 07/2014; DOI:10.1016/j.vetimm.2014.07.004 · 1.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Infection with Neospora caninum stimulates host cell-mediated immune responses, which may be responsible for placental damage leading to bovine abortion. The aim of this study was to compare immune responses in the bovine placenta, following experimental infection in different stages of pregnancy. Placentomes were examined by immunohistochemistry and inflammation in early gestation was generally moderate to severe, particularly in the placentas carrying non-viable foetuses, whereas it was milder in later stages, mainly characterised by the presence of CD3+, CD4+ and gammadelta T-cells. This distinctive cellular immune response may explain the milder clinical outcome observed when animals are infected in later gestation.
    Veterinary Research 01/2014; 45(1):11. DOI:10.1186/1297-9716-45-11 · 3.38 Impact Factor
  • Source
    Apicowplexa 2013: International Meeting on Apicomplexan Parasites in Farm Animals, Kuşadası, Turkey; 10/2013
  • Source
    Apicowplexa 2013: International Meeting on Apicomplexan Parasites in Farm Animals, Kuşadası, Turkey; 10/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study examined the immunological responses of pregnant cattle and their foetuses following an experimental challenge with live Neospora caninum tachyzoites at day 210 of gestation. Animals were bled prior to and weekly throughout the experiment and sacrificed at 14, 28, 42 and 56 days post inoculation (dpi). At post mortem examination, samples of lymph nodes and spleen were collected from both dam and foetus for immunological analysis. Subcutaneous (sc) inoculation over the left prefemoral (LPF) lymph node of pregnant cattle at day 210 of gestation, led to the vertical transmission of parasites by 14 dpi, however no foetal deaths were observed in the infected animals. Foetuses from infected dams mounted Neospora-specific humoral and cell-mediated immune (CMI) responses by 14 dpi. These responses involved anti-Neospora IgG, antigen-specific lymphocyte proliferation, and the production of the cytokines IFN–γ, interleukin (IL)-4 and IL-10. There was also evidence of innate immunity during the response against Neospora from infected dams, with statistically significant (p < 0.05) increases in mean expression of toll like receptors (TLR)-2 on 56 dpi in maternal spleen, LPF, right prefemoral (RPF), left uterine (LUL) and right uterine (RUL) lymph nodes and TLR-9 in retropharyngeal (RLN), LPF and RPF lymph nodes from 28 dpi. Statistically significant (p < 0.05) increases in mean TLR-9 were detected in spleen samples from foetuses of infected dams, compared to the foetuses from control animals. Our results show that vertical transmission of the parasite occurred in all infected dams, with their foetuses showing effective Neospora-specific cell mediated, humoral and innate immune responses.
    Veterinary Research 10/2013; 44(1):91. DOI:10.1186/1297-9716-44-91 · 3.38 Impact Factor
  • Source
    24th International Conference of the World Association for the Advancement of Veterinary Parasitology, Perth, Australia; 08/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The protozoan parasite Toxoplasma gondii (T. gondii) is a zoonotic pathogen that has the ability to infect all warm blooded animals including humans (Tenter et al 2000). Toxoplasmosis is a major opportunistic disease of immunocompromised patients. It also represents a serious threat during pregnancy, causing severe foetal abnormalities or potentially leads to problems in childhood or later adult life (Koppe et al 1986). Undercooked or raw meat containing infective tissue cysts is a significant source of human infection (Cook et al 2000). The production of T. gondii tissue cyst free meat could reduce the risk of human exposure to T. gondii. In two different animal studies a group of 23 pigs and 32 lambs were used to determine the efficacy of a commercially available vaccine that protects sheep from abortions caused by T. gondii, with an aim to reduce tissue cyst formation. Following vaccination, animals were challenged with oocysts. Subsequently a mouse bioassay, using a variety of porcine tissues, resulted in a 100% survival of mice that received tissues from vaccinated/challenged pigs. While bioassays with tissues from non-vaccinated pigs resulted in a survival rate of 51%. Parasite DNA was also identified in the homogenate used in bioassays from the non-vaccinated/challenged group but not in the vaccinated/challenged pigs. In a similar experiment, T. gondii DNA was tested for in the tissues of lambs. Following vaccination and challenge with 100,000 oocysts of the M4 strain, parasite was detected at significantly lower levels in heart and skeletal muscle samples from the vaccinated/challenged group (0% and 5.9% respectively), when compared to the non-vaccinated/challenged animals (75% heart, 87.9% skeletal muscle). These results demonstrate that vaccination of pigs and lambs with the S48 attenuated T. gondii strain can reduce the formation of tissue cysts, resulting in potentially safer meat for human consumption.
    . 24th International Conference of the World Association for the Advancement of Veterinary Parasitology, Perth, Australia; 08/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dogs are the definitive host of the protozoan parasites Neospora caninum and Sarcocystis tenella. Both organisms are capable of infecting different farm livestock species. Protozoan-associated disease is uncommon in adult dogs although Neospora encephalitis, radiculitis and myositis have been reported in puppies. The aim of this work is to describe protozoan encephalitis affecting a 9.9 years-old Greyhound dog. Progressive generalized ataxia and hypermetria affecting all limbs was observed for a period of 2 months with signs of multifocal left forebrain, brainstem and cerebellar lesions. Magnetic resonance imaging demonstrated multifocal white/grey matter cerebral lesions. Serology detected N. caninum (1/800) and Toxoplasma gondii (1/200). After clindamycin treatment no improvement of clinical signs were observed; further deterioration was noted following treatment with corticosteroids. Elective euthanasia was performed. Histopathological analysis revealed severe multifocal to coalescing non-suppurative necrotizing encephalitis with glial foci in the white and grey matter of the cerebrum and cerebellum, with intralesional protozoan structures, interpreted as tissue cysts and free tachyzoites/merozoites. Immunohistochemistry (IHC) using 2 polyclonal antibodies, raised against N. caninum and Sarcocystis spp identified morphologically different tissue cysts and free tachyzoites/merozoites with different intensity of labelling. PCR detected N. caninum and S. tenella in brain tissue. These results confirmed the definitive diagnosis of protozoan encephalitis due to N. caninum and S. tenella. Although antimicrobials such as clindamycin are reported as effective in treating Neospora-encephalitis in puppies, it was unsuccessful in this case. Corticosteroid treatment is likely to have facilitated protozoal proliferation and so increased the severity of the lesions in this dog. Protozoan co-infections are not commonly recognized and IHC is a common ancillary technique used in their diagnosis. Cross-reaction of the antibodies has been reported; therefore the use of this technique on its own may not be enough to achieve a definitive etiological diagnosis. References:  Dubey, J.P., 1976. A review of Sarcocystis of domestic animals and of other coccidia of cats and dogs.. Immune responses against Toxoplasma and Sarcocystis infections in ruminants: diagnosis and prospects for vaccination. Revue scientifique et technique (International Office of Epizootics) 9, 441-462.
    24th International Conference of the World Association for the Advancement of Veterinary Parasitology, Perth, Australia; 08/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Toxoplasmosis is an important zoonoses and humans may acquire infection via consumption of undercooked meat containing tissue cysts. Vaccination has been proposed to reduce parasite burden in meat from animals. The aim of this work is to evaluate the efficiency of a commercially available vaccine on tissue infection following Toxoplasma gondii experimental inoculation. Thirty-two T. gondii-seronegative Suffolk lambs were examined daily and blood samples taken. Twelve (group B) and 5 (group C) lambs were vaccinated with Toxovax® at day 0. Lambs from group A and B were orally inoculated with 500,000 T. gondii oocysts 28 days post-vaccination; group C and D lambs remained un-challenged. Lambs were culled at 14, 28 and 42 days post-inoculation (dpi), and tissue samples including central nervous system (CNS) and skeletal muscle with high commercial value were taken. Serum T. gondii antibodies were detected by ELISA and seroconversion was observed in group B and C lambs after vaccination confirming immunization of the lambs. Group A and B animals showed increase in antibody titers after challenge. T. gondii DNA was detected by PCR in 65.9% and 75.0% of CNS and heart samples from Group A lambs, while Group B, C and D samples were negative. Parasite DNA was detected in 87.9% of skeletal muscular samples from group A, while only 5.9, 3.1 and 0.0% samples were positive in groups B, C and D, respectively. Genotype I (present in the vaccine) and III T. gondii (not included in the vaccine neither inocula) were confirmed after sequencing in muscular samples from group B and C lambs. Vaccination was proven to be effective in significantly reducing formation of tissue cysts in lambs infected with a high dose of T. gondii oocysts, and its use could be recommended to reduce meat contamination. lesions and tissue distribution of parasite in lambs orally infected with sporulated oocysts of Toxoplasma gondii. Veterinary Parasitology 179, 209-215. Falcón, J., Freyre, A., 2009. Toxoplasma gondii: prototype immunization of lambs against formation of muscle and brain cysts. Veterinary Parasitology 166, 15-20.
    24th International Conference of the World Association for the Advancement of Veterinary Parasitology, Perth, Australia; 08/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: SUMMARY Toxoplasma gondii is a zoonotic pathogen defined by three main clonal lineages (types I, II, III), of which type II is most common in Europe. Very few data exist on the prevalence and genotypes of T. gondii in the UK. Wildlife can act as sentinel species for T. gondii genotypes present in the environment, which may subsequently be transmitted to livestock and humans. DNA was extracted from tissue samples of wild British carnivores, including 99 ferrets, 83 red foxes, 70 polecats, 65 mink, 64 badgers and 9 stoats. Parasite DNA was detected using a nested ITS1 PCR specific for T. gondii, PCR positive samples were subsequently genotyped using five PCR-RFLP markers. Toxoplasma gondii DNA was detected within all these mammal species and prevalence varied from 6·0 to 44·4% depending on the host. PCR-RFLP genotyping identified type II as the predominant lineage, but type III and type I alleles were also identified. No atypical or mixed genotypes were identified within these animals. This study demonstrates the presence of alleles for all three clonal lineages with potential for transmission to cats and livestock. This is the first DNA-based study of T. gondii prevalence and genotypes across a broad range of wild British carnivores.
    Parasitology 08/2013; 140(14):1-9. DOI:10.1017/S0031182013001169 · 2.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite Neospora caninum being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. Neospora infection stimulates host cell-mediated immune responses, which may be responsible for the placental damage leading to abortion. The aim of the current study was to characterize the placental immune response following an experimental inoculation of pregnant cattle with N. caninum tachyzoites at day 210 of gestation. Cows were culled at 14, 28, 42 and 56 days post inoculation (dpi). Placentomes were examined by immunohistochemistry using antibodies against macrophages, T-cell subsets (CD4, CD8 and gammadelta), NK cells and B cells. Macrophages were detected mainly at 14 days post inoculation. Inflammation was generally mild and mainly characterized by CD3+, CD4+ and gammadelta T-cells; whereas CD8+ and NK cells were less numerous. The immune cell repertoire observed in this study was similar to those seen in pregnant cattle challenged with N. caninum at early gestation. However, cellular infiltrates were less severe than those seen during first trimester Neospora infections. This may explain the milder clinical outcome observed when animals are infected late in gestation.
    Veterinary Research 07/2013; 44(1):60. DOI:10.1186/1297-9716-44-60 · 3.38 Impact Factor
  • Source
    12th International Congress of Toxoplasmosis, Oxford, Inglaterra; 06/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The protozoan parasite Toxoplasma gondii (T. gondii) is a zoonotic pathogen that has the ability to infect all warm blooded animals including humans. Toxoplasmosis is a major opportunistic disease of immunocompromised patients, and also represents a serious threat during pregnancy causing severe foetal abnormalities or potentially leads to problems in childhood or later adult life. Undercooked or raw meat containing infective tissue cysts are a significant source of human infection. The production of T. gondii tissue cyst free meat could reduce the risk of human exposure to T. gondii. A group of 23 pigs were used to determine the efficacy of a commercially available vaccine that protects sheep from abortion caused by T. gondii, with an aim to reduce tissue cyst formation. Following vaccination, animals were challenged with oocysts of the Moredun M4 strain. Subsequently a mouse bioassay, using a variety of porcine tissues, resulted in 100% survival of mice that received tissues from vaccinated/challenged pigs. While bioassays from the non-vaccinated pigs resulted in a survival rate of 51%. Parasite DNA was also identified in the homogenate used in bioassays from the non-vaccinated/challenged group but not in the vaccinated/challenged tissues. These results demonstrate that vaccination of pigs with the S48 attenuated strain of T. gondii can reduce the formation of tissue cysts, resulting in potentially safer meat for human consumption.
    Royal (Dick) School of Veterinary Studies. Postgraduate Student Day., Edimburgo, UK; 04/2013
  • Source
    Journal of Comparative Pathology; 01/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Pro-inflammatory cytokines (particularly IL-12) are important for initiating protective T helper 1 (Th1)-type immune responses and hence vital for combating intracellular infections and tumours. In situ hybridization (ISH) provides a powerful diagnostic tool allowing the identification and localization of cells producing these mediators in fixed tissues. The objective of this work was to produce a bovine IL-12p40 probe that allows detection of IL-12p40 mRNA in fixed tissues from different ruminant species. The RNA probe sequence is 447 bp in length and from a region with high cross-species-sequence homology (>97.3% homology) to the ovine, cervine, caprine and bubaline IL-12p40 genes. ISH was carried out on paraformaldehyde fixed tissues collected from cattle, sheep and goats. The probe was efficient in identifying IL-12p40 expressing cells in fixed tissues from all these species. In conclusion, the IL-12p40 probe was efficient in identifying and localizing cells that express IL-12p40, and provides a good immuno-diagnostic technique to characterize immune responses in fixed tissues.