Time of year, age class and body condition predict Hendra virus infection in Australian black flying foxes (Pteropus alecto).

Hendra virus (HeV) continues to cause fatal infection in horses and threaten infection in close-contact humans in eastern Australia. Species of Pteropus bats (flying-foxes) are the natural reservoir of the virus. We caught and sampled flying-foxes from a multispecies roost in southeast Queensland, Australia on eight occasions between June 2013 and June 2014. The effects of sample date, species, sex, age class, body condition score (BCS), pregnancy and lactation on HeV antibody prevalence, log-transformed median fluorescent intensity (lnMFI) values and HeV RNA status were assessed using unbalanced generalised linear models. A total of 1968 flying-foxes were sampled, comprising 1012 Pteropus alecto, 742 P. poliocephalus and 214 P. scapulatus. Sample date, species and age class were each statistically associated with HeV RNA status, antibody status and lnMFI values; BCS was statistically associated with HeV RNA status and antibody status. The findings support immunologically naïve sub-adult P. alecto playing an important role in maintaining HeV infection at a population level. The biological significance of the association between BCS and HeV RNA status, and BCS and HeV antibody status, is less clear and warrants further investigation. Contrary to previous studies, we found no direct association between HeV infection and pregnancy or lactation. The findings in P. poliocephalus suggest that HeV exposure in this species may not result in systemic infection and virus excretion, or alternatively, may reflect assay cross-reactivity with another (unidentified) henipavirus.

Landscape Utilisation, Animal Behaviour and Hendra Virus Risk.

Hendra virus causes sporadic fatal disease in horses and humans in eastern Australia. Pteropid bats (flying-foxes) are the natural host of the virus. The mode of flying-fox to horse transmission remains unclear, but oro-nasal contact with flying-fox urine, faeces or saliva is the most plausible. We used GPS data logger technology to explore the landscape utilisation of black flying-foxes and horses to gain new insight into equine exposure risk. Flying-fox foraging was repetitious, with individuals returning night after night to the same location. There was a preference for fragmented arboreal landscape and non-native plant species, resulting in increased flying-fox activity around rural infrastructure. Our preliminary equine data logger study identified significant variation between diurnal and nocturnal grazing behaviour that, combined with the observed flying-fox foraging behaviour, could contribute to Hendra virus exposure risk. While we found no significant risk-exposing difference in individual horse movement behaviour in this study, the prospect warrants further investigation, as does the broader role of animal behaviour and landscape utilisation on the transmission dynamics of Hendra virus.

NALT (nasal cavity-associated lymphoid tissue) in the rabbit.

Due to its many advantages, interest in intranasal vaccination of domestic mammals and humans is currently increasing. Successful stimulation of the immune system by intranasal vaccines requires, however, the presence of lymphoid tissue in the nasal cavity. This nasal cavity-associated lymphoid tissue (NALT) has already been described in humans and many laboratory rodents, but data about rabbits are very scarce. For this purpose, histological sections of the nasal cavities of 10 female adult New Zealand White rabbits were examined for the presence of lymphoid tissue. Primary (I) and secondary (II) lymphoid follicles divided by interfollicular regions were mainly present at the bottom of the ventral nasal meatus and the nasopharyngeal meatus from 1 to 3.3cm from the tip of the nose. In this region intraepithelial and lamina propria lymphocytes, and isolated lymphoid follicles (ILF's) were additionally seen at the dorsal and dorsolateral sides of the nasopharyngeal meatus and within the mucosae of the nasal conchae and the lateral nasal walls. Intraepithelial and lamina propria lymphocytes, and ILF's were, just like in humans, randomly distributed along the entire nasal mucosa. The rabbit NALT is more voluminous compared to rodents in which lymphoid tissue is only present at the bottom of the nasopharyngeal meatus. Since the relative volume of the rabbit nasal cavity is also similar to that of humans, the rabbit could be a valuable research model not only for animal but also for human intranasal vaccine development.

Reproducible and highly sensitive detection of the broad spectrum epithelial marker keratin 19 in routine cancer diagnosis.

AIMS: In this study the recently developed keratin 19 antibody RCK108 is biochemically and immunohistochemically characterized. Its applicability as a keratin marker in routinely processed histological tissue specimens is assessed. METHODS AND RESULTS: The keratin 19 antibody RCK108 antibody was tested on normal and malignant routinely formalin-fixed, paraffin-embedded tissue specimens. It stains most, although not all, glandular epithelia and showed (focal) reactivity in the basal cell compartment of stratified epithelia. It was found to react with most epithelial tumours, including adenocarcinomas, squamous cell carcinomas and endocrine tumours of various origins. CONCLUSIONS: Its reproducible and highly sensitive staining characteristics make RCK108 a useful antibody to be applied as a broad epithelial marker for carcinoma detection in routinely processed paraffin sections. As such, RCK108 is a specific reagent for practically all epithelial tumours. A few types of epithelial malignancies, known not to contain keratin 19, were negative for RCK108. Therefore the antibody is also useful in some narrow differential diagnostic considerations such as cholangiocellular carcinoma (RCK108 positive) vs. hepatocellular carcinoma (RCK108 negative). Another important feature of this antibody is that it shows very little reactivity in mesenchymal tissues, or mesenchymally derived tumours, as is frequently described for other keratin antibodies. A few leiomyosarcomas showed sporadic reactivity.