Pathology and molecular epidemiology of Mycobacterium pinnipedii tuberculosis in native New Zealand marine mammals.

Mycobacterium pinnipedii causes tuberculosis in a number of pinniped species, and transmission to cattle and humans has been reported. The aims of this study were to: characterize the pathology and prevalence of tuberculosis in New Zealand marine mammals; use molecular diagnostic methods to confirm and type the causal agent; and to explore relationships between type and host characteristics. Tuberculosis was diagnosed in 30 pinnipeds and one cetacean.

Whole Genome Sequencing for Determining the Source of Infections in Livestock Herds and Wildlife in New Zealand.

The ability to DNA fingerprint isolates helped to define the role of wildlife in the persistence of bovine tuberculosis in New Zealand. DNA fingerprinting results currently help to guide wildlife control measures and also aid in tracing the source of infections that result from movement of livestock. During the last 5 years we have developed the ability to distinguish New Zealand (NZ) isolates by comparing the sequences of whole genome sequenced (WGS) samples.

Comparison of the BBL mycobacteria growth indicator tube, the BACTEC 12B, and solid media for the isolation of Mycobacterium bovis.

We compared different methods for their ability to isolate Mycobacterium bovis from tissue samples from animals with lesions resembling bovine tuberculosis. In the first trial, M. bovis was isolated from 86 of 200 tissue samples that were cultured using 2 liquid media, BACTEC 12B and BBL mycobacteria growth indicator tube (MGIT), and a solid medium, Middlebrook 7H11 supplemented with pyruvate (7H11P).

Factors affecting the gamma interferon test in the detection of bovine tuberculosis in cattle.

The gamma interferon (IFN-γ) test has been used for many years as an ancillary test in the detection of bovine tuberculosis. We investigated the effect of skin testing and the length of time between blood collection and processing on the performance of the IFN-γ test. A series of blood samples were taken from groups of experimentally infected cattle ( n = 10), naturally infected ( n = 11), and uninfected animals ( n = 12) that were examined with a caudal fold skin test.

Revaccination of cattle with bacille Calmette-Guérin two years after first vaccination when immunity has waned, boosted protection against challenge with Mycobacterium bovis.

In both humans and animals, controversy exists concerning the duration of protection induced by BCG vaccine against tuberculosis (TB) and whether revaccination enhances protection. A long-term study was undertaken to determine whether BCG-vaccinated calves would be protected against challenge with Mycobacterium bovis 2½ years after vaccination and to determine the effect of revaccination after 2 years. Seventy-nine calves were divided into five groups (n = 15-17 calves/group) with four of the groups vaccinated subcutaneously with 105 CFU of BCG Danish at 2-4 weeks of age and the fifth group serving as non-vaccinated controls.

Comparison of gene expression of immune mediators in lung and pulmonary lymph node granulomas from cattle experimentally infected with Mycobacterium bovis.

The cellular infiltrates and macrophage activation pathways may differ in granulomas found in the lungs and pulmonary lymph nodes of cattle infected with Mycobacterium bovis. The aim of this study was to compare the histopathology and gene expression profiles of cytokines and immune mediators for cattle which had these lesions in both sites. Ten Friesian-cross, 15-16 month old cattle were challenged intratracheally with 5 × 10(3)CFU of virulent M.

The seal tuberculosis agent, Mycobacterium pinnipedii, infects domestic cattle in New Zealand: epidemiologic factors and DNA strain typing.

The fur seal (Arctocephalus forsteri), which is abundant in coastal areas of New Zealand, harbors several zoonotic pathogens, including Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex. We describe the microbiology and epidemiology of seven cases of M. pinnipedii infection in beef cattle (Bos primigenius) in coastal areas of New Zealand in 1991-2011.

Immune responses associated with progression and control of infection in calves experimentally challenged with Mycobacterium avium subsp. paratuberculosis.

This study examined the immune responses related to the infection, progression and control of Mycobacterium avium subsp. paratuberculosis (MAP) infection in calves. Twenty calves were challenged orally with MAP and 11 non-challenged calves served as controls.

Altered patterns of toll-like receptor gene expression in cull cows infected with Mycobacterium avium subsp. paratuberculosis.

Johne's disease caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic enteric disease of cattle. The mechanism how MAP can co-exist in the gastro-intestinal tract despite a massive infiltration of immune cells is not known.

Low oral BCG doses fail to protect cattle against an experimental challenge with Mycobacterium bovis.

Studies were undertaken to determine whether a dose of oral Mycobacterium bovis bacillus Calmette-Guérin (BCG) which did not induce skin test reactivity could protect cattle against bovine tuberculosis (TB). Groups of calves (n = 9) were vaccinated by administering 10(8), 10(7) or 10(6) colony forming units (CFU) of BCG orally or 10(6) CFU subcutaneous (s.c.

Diverse cytokine profile from mesenteric lymph node cells of cull cows severely affected with Johne's disease.

Mycobacterium avium subsp. paratuberculosis, the causative agent of Johne's disease, is able to dampen or distort immune responses at the mucosal sites and coexist with a massive infiltration of immune cells in the gastrointestinal tract. Knowledge of the mechanism by which M.

Immunogenicity and protective efficacy of mycobacterial DNA vaccines incorporating plasmid-encoded cytokines against Mycobacterium bovis.

DNA-based vaccines, alone or in combination with other sub-unit vaccination regimes, represent an alternative to live mycobacterial vaccines for protective immunization against tuberculosis. Here, we have used a murine immunization or Mycobacterium bovis aerosol challenge model to assess the immunogenicity and protective efficacy of mycobacterial DNA vaccines. Mice that received immunization with DNA constructs encoding M.

Assessment of live candidate vaccines for paratuberculosis in animal models and macrophages.

Mycobacterium avium subsp. paratuberculosis (basonym M. paratuberculosis) is the causative agent of paratuberculosis, a chronic enteritis of ruminants.

Accelerating the secondary immune response by inactivating CD4(+)CD25(+) T regulatory cells prior to BCG vaccination does not enhance protection against tuberculosis.

CD4(+)CD25(+) natural T regulatory cells (Tregs) have been shown to suppress protective immune responses in several different vaccination models. Since the effect of Tregs on vaccination against tuberculosis (Tb) was unknown, we used a murine model to investigate whether natural Tregs suppress the development of protective immunity following Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccination. Using a monoclonal antibody against CD25, natural Tregs were inactivated prior to vaccination with BCG.

A new attenuated Mycobacterium bovis vaccine protects brushtail possums (Trichosurus vulpecula) against experimental tuberculosis infection.

Vaccination of wildlife against bovine tuberculosis is being actively considered in countries that have wildlife reservoirs of Mycobacterium bovis infection. A newly attenuated strain of M. bovis (WAg533) was produced as part of a programme to develop a better vaccine than BCG to control tuberculosis in brushtail possums in New Zealand.

Experimental challenge models for Johne's disease: a review and proposed international guidelines.

An international committee of Johne's disease (JD) researchers was convened to develop guidelines for JD challenge studies in multiple animal species. The intent was to develop and propose international standard guidelines for models based on animal species that would gain acceptance worldwide. Parameters essential for the development of long-term and short-term infection models were outlined and harmonized to provide a "best fit" JD challenge model for cattle, goats, sheep, cervids, and mice.

Inactivation of CD4+ CD25+ regulatory T cells during early mycobacterial infection increases cytokine production but does not affect pathogen load.

Mycobacterium tuberculosis uses numerous mechanisms to avoid elimination by the infected host. In this study, we investigated the possibility whether, similar to other pathogens, M. tuberculosis exploits natural CD4+ CD25+ T-regulatory cells (Treg) to suppress the effector function of responding host lymphocytes, thus enhancing its survival.

The order of prime-boost vaccination of neonatal calves with Mycobacterium bovis BCG and a DNA vaccine encoding mycobacterial proteins Hsp65, Hsp70, and Apa is not critical for enhancing protection against bovine tuberculosis.

Priming neonatal calves at birth with a Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine and boosting with a DNA vaccine consisting of plasmids encoding mycobacterial antigens Hsp65, Hsp70, and Apa or the reverse prime-boost sequence induced similar levels of protection against experimental challenge with Mycobacterium bovis. When M. bovis was isolated from a thoracic lymph node following challenge, the two groups of calves given the prime-boost regimen had significantly lower numbers of M.

Susceptibility of brushtail possums (Trichosurus vulpecula) infected with Mycobacterium bovis is associated with a transient macrophage activation profile.

The Australian brushtail possums are highly susceptible to Mycobacterium bovis and are the principal wildlife reservoir of M. bovis in New Zealand. To better understand the disease process in these animals, brushtail possums were infected by the aerosol route with a virulent strain of M.

Vaccination of cattle with a CpG oligodeoxynucleotide-formulated mycobacterial protein vaccine and Mycobacterium bovis BCG induces levels of protection against bovine tuberculosis superior to those induced by vaccination with BCG alone.

The development of a subunit protein vaccine for bovine tuberculosis which could be used either in combination with Mycobacterium bovis BCG (to improve the efficacy of that vaccine) or alone would offer significant advantages over currently available strategies. A study was conducted with cattle to determine the protective efficacy of a strategy based on concurrent immunization with an M. bovis culture filtrate (CFP) vaccine and BCG compared to vaccination with either vaccine alone.

Effect of oral vaccination of cattle with lipid-formulated BCG on immune responses and protection against bovine tuberculosis.

Cattle were given Mycobacterium bovis bacillus Calmette-Guerin (BCG) in a lipid-based formulation via the oral route and tested for immune responses and protection against a challenge with virulent M. bovis. Calves were vaccinated by orally administering a pellet containing 10(8) colony forming units (CFU) of BCG, or 10 pellets containing a total of 10(9) CFU of BCG, whereas positive controls were injected subcutaneously with 10(6) CFU of BCG.

Generation of attenuated Mycobacterium bovis strains by signature-tagged mutagenesis for discovery of novel vaccine candidates.

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, has a particularly wide host range and causes tuberculosis in most mammals, including humans. A signature tag mutagenesis approach, which employed illegitimate recombination and infection of guinea pigs, was applied to M. bovis to discover genes important for virulence and to find potential vaccine candidates.