Genetic characterization of flea-derived Bartonella species from native animals in Australia suggests host-parasite co-evolution

Fleas are important arthropod vectors for a variety of diseases in veterinary and human medicine, and bacteria belonging to the genus Bartonella are among the organisms most commonly transmitted by these ectoparasites. Recently, a number of novel Bartonella species and novel species candidates have been reported in marsupial fleas in Australia. In the present study the genetic diversity of marsupial fleas was investigated; 10 species of fleas were collected from seven different marsupial and placental mammal hosts in Western Australia including woylies (Bettongia penicillata), western barred bandicoots (Perameles bougainville), mardos (Antechinus flavipes), bush rats (Rattus fuscipes), red foxes (Vulpes vulpes), feral cats (Felis catus) and rabbits (Oryctolagus cuniculus). PCR and sequence analysis of the cytochrome oxidase subunit I (COI) and the 18S rRNA genes from these fleas was performed. Concatenated phylogenetic analysis of the COI and 18S rRNA genes revealed a close genetic relationship between marsupial fleas, with Pygiopsylla hilli from woylies, Pygiopsylla tunneyi from western barred bandicoots and Acanthopsylla jordani from mardos, forming a separate cluster from fleas collected from the placental mammals in the same geographical area. The clustering of Bartonella species with their marsupial flea hosts suggests co-evolution of marsupial hosts, marsupial fleas and Bartonella species in Australia

Comparison of the biotypes of Yersinia enterocolitica isolated from pigs, cattle and sheep at slaughter and from humans with yersiniosis in Great Britain during 1999-2000

Aims: To investigate the relationship between livestock carriage of Yersinia enterocolitica and human disease. The biotypes/serotypes of strains recovered from the faeces of pigs, cattle and sheep at slaughter during a national survey in Great Britain in 1999-2000, were compared with those of strains isolated from human cases of yersiniosis during the same period. Methods and Results: The faecal carriage of Y. enterocolitica by cattle, sheep and pigs at slaughter was 6.3, 10.7 and 26.1%, respectively. Yersinia enterocolitica biotype (BT) 1a was the most frequently isolated biotype from livestock (58%) and was the predominant biotype (53%) isolated from human cases over the same period. The main recognized pathogenic Y. enterocolitica biotype isolated from livestock was BT3 (O:5,27) (35% of sheep, 22% of pigs and 4% of cattle) but this biotype was not detected in any of the human isolates investigated. The major pathogenic biotypes of strains isolated from humans were BT3 (O:9) (24%) and BT4 (O:3) (19%) whereas of the veterinary isolates investigated, only pigs (11%) carried BT3 (O:9) strains. Conclusions: Because of significant overlaps in phenotypes of the veterinary and human strains it is not possible to comment on the correlation between host and pathogenicity, especially of biotype 1a. Significance and Impact of the Study: The data suggest that further investigations using methods with greater discriminatory power are required. However the data also suggests that pigs may be the primary reservoir for human pathogenic Y. enterocolitica infection

Evaluation of a subunit H5 vaccine and an inactivated H5N2 avian influenza marker vaccine in ducks challenged with Vietnamese H5N1 highly pathogenic avian influenza virus

The protective efficacy of a subunit avian influenza virus H5 vaccine based on recombinant baculovirus expressed H5 haemagglutinin antigen and an inactivated H5N2 avian influenza vaccine combined with a marker antigen (tetanus toxoid) was compared with commercially available inactivated H5N2 avian influenza vaccine in young ducks. Antibody responses, morbidity, mortality, and virus shedding were evaluated after challenge with a Vietnamese clade 1 H5N1 HPAI virus [A/VN/1203/04 (H5N1)] that was known to cause a high mortality rate in ducks. All three vaccines, administered with water-in-oil adjuvant, provided significant protection and dramatically reduced the duration and titer of virus shedding in the vaccinated challenged ducks compared with unvaccinated controls. The H5 subunit vaccine was shown to provide equivalent protection to the other two vaccines despite the H5 antibody responses in subunit vaccinated ducks being significantly lower prior to challenge. Ducks vaccinated with the H5N2 marker vaccine consistently produced antitetanus toxoid antibody. The two novel vaccines have attributes that would enhance H5N1 avian influenza surveillance and control by vaccination in small scale and village poultry systems

The application of One Health concept to an outdoor problem-based learning activity for veterinary students

Background: The One Health (OH) approach, which seeks to bring together human and animal health, is particularly suited to the effective management of zoonotic diseases across both sectors. To overcome professional silos, OH needs to be taught at the undergraduate level. Here, we describe a problem-based learning activity using the OH approach that was conducted outdoors for 3rd-year veterinary students in Malaysia. Materials and Methods: A total of 118 students, divided into two groups, completed the activity which spanned 11/2 days at a deer park adjacent to a wilderness area. Students were asked to evaluate the activity using an online survey that had quantitative and qualitative components. Results: Response rate was 69.5%. The activity was rated excellent by 69.5% and good by 30.4%. Levels of satisfaction were high on a range of criteria. 97.5% of students intended to take action in their studies as a result of what they had learned. Conclusions: Delivery of an outdoor problem-based learning activity using OH approach was very successful in terms of participation, knowledge delivery and understanding, and the willingness of students to integrate OH into their future practice. For the improvement of future programs, the involvement of other disciplines (such as Medical, Biology, Biotechnology, Biomedical, and Public Health) is being considered

Prevalence of Salmonella in fecal samples of western grey kangaroos (Macropus fuliginosus)

This is the first extensive study of the prevalence of naturally acquired Salmonella infection in wild-caught kangaroos in Australia. Given the close association between kangaroos, livestock, and humans and the growing popularity of kangaroo meat, it is important to identify epidemiologic factors associated with infection in these marsupials in order to minimize the risk of Salmonella transmission. The overall prevalence of fecal Salmonella in 645 western grey kangaroos (Macropus fuliginosus) sampled across 10 locations in Western Australia was 3.6% (95% CI: 2.3–5.3). Seven Salmonella serovars were identified including Salmonella enterica serovar Muenchen, Kiambu, Rubislaw, Lindern, Champaign, Saintpaul and II 42:g,t:-. Prevalence was significantly associated with rainfall (P<0.05) and was highest in the April–June quarter (P<0.05). There was no association between age or sex and the prevalence of Salmonella in fecal samples. Our results suggest that, while kangaroos are infected with Salmonella in their natural habitat, infection is less common than in hand-reared joeys, pet kangaroos, and macropods raised in captivity. Care should be taken to maintain hygiene during the evisceration, processing, and handling of kangaroos and to adequately cook kangaroo meat prior to consumption to reduce the risk of salmonellosis

A survey of Western Australian sheep, cattle and kangaroos to determine the prevalence of Coxiella burnetii

The objective of this study was to investigate the prevalence of Coxiella burnetii in two domestic ruminant species (cattle and sheep) and the western grey kangaroo (Macropus fuliginosus) in Western Australia (WA). The IDEXX CHEKiT Q Fever ELISA and CFT were used to test sera from 50 sheep and 329 head of cattle for anti- C. burnetii antibodies and 343 kangaroo sera were tested using an indirect ELISA developed specifically for this study. Faecal or urine samples collected from the same animals were tested with two PCR assays to identify active shedding of C. burnetii in excreta. Only two of the 379 ruminant sera had detectable levels of anti- C. burnetii antibodies according to the ELISA while the CFT did not detect any positive samples. In contrast 115 of the 343 western grey kangaroo serum samples were positive when tested with the antibody-ELISA. The first qPCR assay, targeting the IS1111a element, identified 41 of 379 ruminant and 42 of 343 kangaroo DNA samples as positive for C. burnetii DNA. The second qPCR, targeting the JB153-3 gene, identified nine C. burnetii DNA-positive ruminant samples and six positive kangaroo samples. Sequence comparisons showed high degrees of identity with C. burnetii. Isolation of C. burnetii from faeces was also attempted but was not successful. From the results presented here it appears that domestic ruminants may not be the most significant reservoir of C. burnetii in WA and that kangaroos may pose a significant threat for zoonotic transfer of this pathogen

High prevalence of Rickettsia gravesii sp. nov. in Amblyomma triguttatum collected from feral pigs

A survey of ectoparasites on feral pigs identified two commonly occurring ixodid tick species; Amblyomma triguttatum triguttatum and Ixodes australiensis. Molecular screening of A. t. triguttatum and I. australiensis for the presence of Rickettsia species detected the presence of rickettsiae belonging to the Spotted Fever Group (SFG) in 78.4% of screened A. t. triguttatum. None of the screened I. australiensis were positive for rickettsiae. Sequence analysis of the gltA and ompA loci of positive Rickettsia isolates were 100% homologous to the newly described species Rickettsia gravesii sp. nov. BWI-1. Serological screening of feral pigs detected antibodies to SFG Rickettsia in 50% of serum samples tested. These findings suggest that A. t. triguttatum is a vector/reservoir for R. gravesii sp. nov

Seroprevalence of Toxoplasma gondii in wild kangaroos using an ELISA

Infection with Toxoplasma gondii is a significant problem in Australian marsupials, and can lead to devastating disease and predispose animals to predation. T. gondii infection in kangaroos is also of public health significance due to the kangaroo meat trade. A moderate seroprevalence of T. gondii was observed in a study of western grey kangaroos located in the Perth metropolitan area in Western Australia. Of 219 kangaroos tested, 15.5% (95%CI: 10.7-20.3) were positive for T. gondii antibodies using an ELISA developed to detect T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA developed was in absolute agreement and yielded a κ coefficient of 1.00. Of 18 kangaroos tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay

Prevalence of Coxiella burnatii in western grey kangaroos (Macropus fuliginosus) in Western Australia

We investigated the role of the western grey kangaroo (Macropus fuliginosus) in the maintenance and transmission of Coxiella burnetti in Western Australia. Sera from 1,017 kangaroos were tested using an indirect enzyme-linked immunosorbent assay (ELISA) for the presence of C. burnetii antibodies. The overall antibody prevalence across 12 locations throughout mid- to southwestern Western Australia was 24.1% (95% CI: 21.6-26.8). Feces from 990 of the same animals were tested using PCR to identify active shedding of C. burnetii in excreta. Coxiella burnetii DNA was detected in 4.1% (95% CI: 3.1-5.6) of samples. Our results suggest that kangaroos are reservoirs for C. burnetti in Western Australia and may contribute to transmission of the organism to domestic livestock and humans

Essential veterinary education in the virology of domestic animals, wild animals and birds: diagnosis and pathogenesis of viral infections

An education in veterinary virology should establish a basis for life-long learning and enable veterinary graduates to address professionally the control and eradication of viral diseases, both locally and globally. It is therefore more important that the curriculum focuses on a sound understanding of the nature and behaviour of viruses and their interactions with animal hosts, rather than imparting detailed information on an ever-increasing number of individual viral diseases in a widening range of animal species. Graduate veterinarians should be prepared with a comprehensive knowledge of the nature of viruses and their close dependence on the hosts that they infect, as well as a good understanding of pathogenesis, immunology, epidemiology, diagnostic approaches and control options. All these are necessary if the profession is successfully to meet familiar and new challenges in viral diseases in a wide range of host species, under different management conditions, in various geographic areas of the world