Vector-borne and zoonotic diseases of dogs in North-west New South Wales and the Northern Territory, Australia.

BACKGROUND: Vector-borne diseases of dogs in Australian Aboriginal communities are relatively unexplored. These dogs represent a unique group with variable ecto- and endo-parasitic burdens, nutritional stresses and a general lack of veterinary intervention. We investigated haemoprotozoal and bacterial pathogen prevalences in relation to erythrocyte and platelet numbers in dogs from North-West New South Wales (N-W NSW) and the Northern Territory (NT; Central Australia). METHODS: Real-time PCR (qPCR) amplification of Anaplasma platys, Babesia vogeli, Mycoplasma haemocanis, Candidatus Mycoplasma haematoparvum and Bartonella spp., serological screening for Coxiella burnetii, and Bartonella spp. and haematological analyses were performed on dogs from the two cohorts (96 dogs in total). Brucella suis serology was determined additionally for the N-W NSW cohort. RESULTS: Anaplasma platys (n = 26 dogs), Babesia vogeli (n = 7), Candidatus Mycoplasma haematoparvum (n = 10 dogs), and Mycoplasma haemocanis (n = 14) were detected in the sample population (n = 96) using qPCR. There were significant associations between (i) A. platys and anaemia (OR 8.7, CI 2.4-31.7; P < 0.001), thrombocytopenia (OR 12.1, CI 3.4-43.2; P < 0.001) and breed (OR 16.1, CI 2.1-121.5; P = 0.007), and (ii) between B. vogeli and anaemia (OR 11.8, CI 2.3-61.6; P = 0.003). Neither protozoal nor bacterial DNA loads, estimated using qPCR, were positively correlated with anaemia or thrombocytopenia. Haemotropic mycoplasmas were not associated with any haematologic abnormality. Four dogs from the NT were seropositive for Coxiella burnetii, while no dogs were seropositive for Brucella suis or to a panel of Bartonella spp. antigens. Despite directed efforts, Bartonella DNA was not detected in blood from any of the cohorts studied. A sample of dogs from the NT recruited specifically for Bartonella α-proteobacteria growth medium enrichment blood culture were also Bartonella PCR negative. CONCLUSIONS: Vector-borne pathogens occur in dogs free ranging near Aboriginal communities, with higher detection rates in NT than N-W NSW. The preponderant haematologic abnormalities were anaemia and thrombocytopenia, likely attributable to A. platys and B. vogeli infections, but also probably affected by nutritional, parasitic, lactational and environmental stressors. The absence of Bartonella spp. is of importance to the Australian setting, and work needs to be extended to tropical coastal communities where fleas are present as well as ticks. Dogs living in and around Aboriginal communities may provide valuable sentinel information on disease infection status of human public health significance.

Pharmacokinetic profile of oral and subcutaneous administration of paracetamol in the koala (Phascolarctos cinereus) and prediction of its analgesic efficacy.

The pharmacokinetic profile of paracetamol in koalas is described when administered orally at 15 mg/kg; followed by the same dose, administered every 12 hours (hrs), repeated five times. After the initial oral administration, the median (range) maximal plasma concentration (Cmax), the time Cmax was reached (Tmax) and elimination half-life (t1/2) were 16.93 µg/mL (13.66 to 20.25 µg/mL); 4 hrs (4 to 8 hrs) and 5.54 hrs (4.66 to 7.67 hrs), respectively. When paracetamol was administered orally at 15 mg/mL every 12 hrs, the trough total plasma concentration range remained comparable to the therapeutic range in humans i.e. 4 to 20 µg/mL that is known to provide some analgesia. However, there is a smaller proportion of free drug (i.e. not bound to plasma proteins; and the active form) available in koala plasma (approximately 40% unbound) compared to human plasma (approximately 80% unbound). Consequently, even when there are similar total drug plasma concentrations in both koala and human plasma, the therapeutic efficacy may be reduced in koalas compared to humans. The initial oral dose and subsequent twice daily doses resulted in no obvious adverse effects in any koala. Haematology, plasma electrolyte and biochemical analyte values remained within their reference ranges eight hrs after the last dose but there was a significant change in alanine transaminase (ALT) levels (an increase), and in total protein (a decrease) (both p = 0.03). A dose of 15 mg/kg was also administered as a subcutaneous injection, diluted 50:50 with saline, to two koalas. As the oral formulation and the subcutaneous administration resulted in comparable absorption, the study focused on the oral profile. Based on these results there is an argument to recommend a slight increase in the oral paracetamol dose for the koala, however further investigation is required to confirm whether repeated administration of a slightly higher dose may be associated with more severe or additional significant changes in haematology, electrolytes or biochemical analytes. However, a preferable recommendation would be to administer this dosage of paracetamol in combination with another analgesic such as tramadol, as a subcutaneous injection, to improve efficacy.

Differences in Gut Microbiome Profile between Healthy Children and Children with Inflammatory Bowel Disease and/or Autoimmune Liver Disease: A Case-Control Study.

BACKGROUND: The role of gastrointestinal microbiome in health and disease is increasingly appreciated. A significant amount of evidence clearly points to a dysbiosis manifest in inflammatory bowel disease (IBD) when compared to healthy controls. Less understood is the microbiome profile in autoimmune liver disease (AILD). Both adult and paediatric data indicate a distinct microbial signature in patients with IBD and co-existent primary sclerosing cholangitis (PSC), which is unique and different compared to the microbial signature that exists in patients with IBD alone. However, there is limited information on the microbiome make-up of patients with parenchymal liver disease, with or without IBD. METHODS: The present study sought to compare the microbiome of children with IBD, to those with IBD-AILD, those with AILD alone and those of healthy controls. RESULTS: Results from this work indicate that children with AILD have a microbiome profile that mirrors healthy controls. CONCLUSION: Those with IBD-AILD and IBD have similar microbiome profiles which are distinct from AILD alone and healthy controls. This suggests that the dysbiosis in these groups is primarily due to IBD rather than AILD.

Seroprevalence of Coxiella burnetii in domesticated and feral cats in eastern Australia.

The seroprevalence of Coxiella burnetii (C. burnetii) in cats in eastern Australia is unknown, and the risk of transmission from cats to humans is undetermined. This study aimed to determine the exposure of cats to C. burnetii in four distinct cat subpopulations. An indirect immunofluoresence assay (IFA) and an Enzyme-linked immunosorbent assay (ELISA) used for detection of anti-C. burnetii antibodies in humans were adapted, verified for use on feline serum, and compared. Cat serum samples (n=712) were tested with IFA from four subpopulations [cattery-confined breeding cats, pet cats, feral cats and shelter cats]. The proportions of seropositive cats were; cattery-confined breeding cats (35/376, 9.3%), pets (2/198, 1%), feral cats (0/50), shelter cats (0/88). The significant variables in C. burnetii seropositivity were cattery-confined breeding cat subpopulation and sterilisation status, with infected cats 17.1 (CI 4.2-70.2; P<0.001) times more likely to be cattery-confined breeding cats and 6.00 (CI 2.13-16.89; P<0.001) times more likely to be entire than sterilised. ELISA was used on 143 of 712 sera tested with IFA, and the Cohen's Kappa coefficient of 0.75 indicated 92.2% agreement between the two assays. These results confirm that Australian cats have been exposed to C. burnetii and that a higher seroprevalence of C. burnetii is seen amongst cattery-confined breeding cats. Cat breeders and veterinary personnel involved in feline reproductive procedures may be at higher risk of exposure to C. burnetii.