Fatal marine
Brucella
infections with histologic lesions specific to the central nervous system (CNS), known as neurobrucellosis, have been described in 5 species of odontocete cetaceans in the UK: ...striped dolphins
Stenella coeruleoalba
, Atlantic white-sided dolphins
Lagenorhynchus acutus
, short-beaked common dolphins
Delphinus delphis
, long-finned pilot whale
Globicephala melas
and Sowerby’s beaked whale
Mesoplodon bidens
. To date, these CNS lesions have only been associated with
Brucella ceti
ST26 and not with
B. pinnipedialis
, which is rarely isolated from cetaceans and, although commonly found in various seal species, has never been associated with any pathology. This paper describes the first report of neurobrucellosis in a common minke whale
Balaenoptera acutorostrata
which was associated with the isolation of
Brucella pinnipedialis
ST24 and co-infection with
Balaenoptera acutorostrata
gamma-herpesvirus 2. This is the first report of neurobrucellosis in any species of mysticete and the first report of
Brucella pinnipedialis
in association with any pathology in any species of marine mammal, which may be due to co-infection with a herpesvirus, as these are known to be associated with immunosuppression.
Brucella ceti
has been recovered from a number species of cetaceans worldwide over the last 25 yr. Here we report, for the first time, the recovery of
B. ceti
from a Risso’s dolphin
Grampus griseus
...and a killer whale
Orcinus orca
. Recovery from an abdominal mass in the dolphin provides further evidence of the systemic pathogenic potential for
B. ceti
infection in cetaceans. The isolation of
B. ceti
ST23 (porpoise cluster) from a killer whale from a group known to eat other marine mammals raises the possibility of infection via ingestion. This report takes the number of cetacean species in UK coastal waters from which
B. ceti
has been isolated to 11 and highlights the value of routine, comprehensive and specific screening for significant pathogens such as
Brucella
sp. by strandings networks.
Phocid herpesvirus 1 (PhHV-1) is known to infect grey seals Halichoerus grypus but little is known about its pathogenicity or true prevalence in this species. To investigate the prevalence of and ...risk factors associated with PHV-1 infection, nasal swabs were collected from grey seal pups and yearlings on the Isle of May, a well-studied grey seal breeding colony, and from stranded grey seal pups submitted to a rehabilitation centre. PhHV-1 nucleic acids were detected in nasal swabs from 58% (52/90) of live free-ranging grey seal pups, 62% (18/29) of live stranded grey seal pups and 28% (5/18) of live free-ranging yearlings, suggesting recrudescence in the latter. Location within the colony, pup body mass and stranding were determined to be risk factors for shedding PhHV-1 in live seal pups with a significantly higher prevalence of PhHV-1 in pups born on the tidal boulder beach when compared to other sites; a significantly positive correlation of PhHV-1 shedding and pup body mass and a higher prevalence in stranded grey seal pups compared to their free-ranging conspecifics. The prevalence of PhHV1 in dead pups on the Isle of May was 56% (27/48) with a positive PhHV-1 PCR status significantly associated with hepatic necrosis (p = 0.01), thymic atrophy (p < 0.001) and buccal ulceration (p = 0.027). Results indicate that PhHV1 was widespread in the pups in the Isle of May grey seal breeding colony.
Campylobacter pinnipediorum
was described recently for isolates recovered from pinnipeds. The novel species was further split into 2 subspecies based on host and geography, with
C. pinnipediorum
...subsp.
pinnipediorum
recovered from otariid seals in California (USA) and
C. pinnipediorum
subsp.
caledonicus
recovered from phocid seals in Scotland. We report details of the infections of 7 pinnipeds from which
C. pinnipediorum
was isolated:
C. pinnipediorum
subsp.
caledonicus
was isolated from 2 harbour seals
Phoca vitulina
and a single grey seal
Halichoerus grypus
, and
C. pinnipediorum
subsp.
pinnipediorum
was isolated from California sea lions
Zalophus californianus
. Six of the isolates were recovered from samples collected at post-mortem investigation. In 2 of the Scottish seals and in 3 of the California seals,
C. pinnipediorum
was the sole bacterial isolate recovered from abscesses present and suggests they may have resulted from conspecific or intraspecific bite wounds.
Brucella species infecting marine mammals was first reported in 1994 and in the years since has been documented in various species of pinnipeds and cetaceans. While these reports have included ...species that inhabit Arctic waters, the few available studies on bearded seals Erignathus barbatus have failed to detect Brucella infection to date. We report the first isolation of Brucella pinnipedialis from a bearded seal. The isolate was recovered from the mesenteric lymph node of a bearded seal that stranded in Scotland and typed as ST24, a sequence type associated typically with pinnipeds. Furthermore, serological studies of free-ranging bearded seals in their native waters detected antibodies to Brucella in seals from the Chukchi Sea (1990-2011; 19%) and Svalbard (1995-2007; 8%), whereas no antibodies were detected in bearded seals from the Bering Sea or Bering Strait or from captive bearded seals.
Fatal Brucella ceti infection with histological lesions specific to the central nervous system has been described in only 3 species of cetaceans: striped dolphins Stenella coeruleoalba, Atlantic ...white-sided dolphins Lagenorhynchus acutus and short-beaked common dolphins Delphinus delphis. This paper describes the first report of a B. ceti-associated meningoencephalitis in a long-finned pilot whale Globicephala melas, showing the increasing range of species susceptibility. Brucella was recovered in larger numbers from cerebrospinal fluid than from brain tissue and is the sample of choice for isolation.
The Gram-negative bacterium Pasteurella multocida causes pneumonic and systemic pasteurellosis in bovids for which vaccines are either unavailable or inadequate. The work assessed whether an ...intranasal P. multocida challenge in mice might provide a model of infection for future vaccine development work. Clinical, pathological and biochemical responses were compared in seven strains of mice challenged with a virulent bovine pneumonic isolate of P. multocida A:3. Six mouse strains (Porton, CD-1, BALB/c, VM, C57BL/10 and C57BL/6) developed clinical signs of pneumonic disease and variable pneumonic lesions 41–70h post-infection. In contrast, mouse strain RIII became septicaemic within 36h post-infection. Concentrations of plasma acute phase proteins and serum lipopolysaccharide increased in all mice after infection, and the main or interaction effect of mouse strain and infection status was statistically significant (P<0.05). Responses in C57BL/10 mice showed close similarity to bovine pneumonic and in RIII mice to bovine systemic pasteurellosis.
Summary
Background
Neutrophil apoptosis and phagocytic clearance have been proposed as key determinants affecting the resolution of airway inflammation.
Objective
To determine the kinetics of ...neutrophil priming, recruitment, activation and subsequent clearance in a naturally occurring equine disease model of neutrophilic pulmonary inflammation.
Methods and Results
A 5 h mouldy hay/straw challenge in hypersensitive horses induced transient pulmonary dysfunction lasting 4 days. At 24 h circulating neutrophils were primed and displayed delayed rates of spontaneous apoptosis in vitro. Neutrophil numbers in the airspaces peaked at 5 h and then fell abruptly, returning to pre‐challenge levels by 4 days. Airspace neutrophils demonstrated increased respiratory burst activity compared with circulating cells and equine neutrophil elastase 2A concentrations increased in parallel with neutrophil numbers indicating in vivo priming and degranulation. The number of apoptotic neutrophils and proportion of alveolar macrophages containing phagocytosed apoptotic neutrophils increased significantly at 24 h and 4 days post‐challenge corresponding to the period of most rapid neutrophil clearance.
Conclusion
This is the first demonstration of spontaneous neutrophil apoptosis and phagocytic removal in a natural disease model of airway inflammation and provides critical kinetic data to support the hypothesis that this clearance pathway plays a central role in the resolution of neutrophilic inflammation.
Samples of tissue from the central nervous system (CNS), the lymphoreticular system (LRS) and the rectal mucosa of a large number of scrapie-exposed sheep, with and without signs of clinical disease, ...were examined immunohistochemically for evidence of disease-associated prion protein (PrPd). The rectal mucosa has received almost no attention so far in scrapie diagnosis, despite its abundant rectoanal mucosa-associated lymphoid tissue, and its accessibility. The scrapie-confirmed cases included 244 with clinical disease, of which 237 (97·1 per cent) were positive in the rectal mucosa, and 121 apparently healthy sheep, of which 104 (86 per cent) were positive in the rectal mucosa. PrPd was detected in 86·4 to 91·5 per cent of the other LRS tissues of the healthy sheep examined and in 77·7 per cent of their CNS tissues. The stage of infection, therefore, affected the probability of a positive result in the rectal mucosa, whereas the breed, PrP genotype, age and sex had little or no independent effect. Accumulations of PrPd were observed in the rectal mucosa and other LRS tissues of VRQ/ARR sheep with preclinical and clinical scrapie, albeit with a lower frequency and magnitude than in sheep of other PrP genotypes. Western immunoblotting analyses of samples of rectal mucosa gave the characteristic PrP glycoprofile, with a sensitivity similar to that of immunohistochemistry.
Two groups of four calves each were immunized either intramuscularly (i.m. vaccinated) or intranasally (i.n. vaccinated) at 2 and 6 weeks of age with ca. 10⁹ CFU of a derivative of P. multocida ...serotype B:2 strain 85020 containing a deletion in the aroA gene (strain JRMT12). Both groups of calves and three unvaccinated control calves were challenged subcutaneously at 8 weeks of age with ca. 10⁷ CFU of the wild-type 85020 strain. The first and second vaccinations caused a significant pyrexia and increase in the mean demeanor score (P < 0.05) in i.m. but not i.n. vaccinated calves. Serum agglutinating activity against whole cells of P. multocida strain 85020 and immunoglobulin G antibody concentrations increased after the second vaccination in i.m. but not in i.n. vaccinated animals, and this difference was statistically significant (P < 0.05). Concentrations of serum amyloid A (SAA) increased significantly 3 h after both the primary (P < 0.05) and booster (P < 0.001) i.m. vaccinations, but not in i.n. vaccinated calves. All four i.m. vaccinated calves were solidly immune to challenge with wild-type P. multocida B:2. However, the mean rectal temperatures, demeanor scores, and serum SAA concentrations of i.n. vaccinated and control calves increased significantly (P < 0.01). Three i.n. vaccinated and two control calves were killed for humane reasons within 14 h postchallenge, and postmortem examination revealed pathological lesions consistent with hemorrhagic septicemia. These data showed that the aroA mutant strain, given i.m. as two doses 4 weeks apart, acted as an effective live-attenuated vaccine strain to protect calves against challenge with the virulent parent strain.
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