Melioidosis is a notifiable infectious disease registered with the Ministry of Health (MOH) and Agri-Food & Veterinary Authority (AVA), Singapore. From a clinical perspective, increased awareness of the disease has led to early detection and treatment initiation, thus resulting in decreasing mortality rates in recent years. However, the disease still poses a threat to local pet, zoo and farm animals, where early diagnosis is a challenge. The lack of routine environmental surveillance studies also makes prevention of the disease in animals difficult. To date, there have been no reports that provide a complete picture of how the disease impacts the local human and animal populations in Singapore. Information on the distribution of Burkholderia pseudomallei in the environment is also lacking. The aim of this review is to provide a comprehensive overview of both published and unpublished clinical, veterinary and environmental studies on melioidosis in Singapore to achieve better awareness and management of the disease.

Birds need to respond to weather changes quickly and appropriately for their own well-being and survival. The inability to respond appropriately to heat waves can be fatal to individual birds and can translate into large-scale mortality events. We investigated corticosterone (CORT) and heterophil∶lymphocyte (H∶L) ratio responses of budgerigars (Melopsittacus undulatus), zebra finches (Taeniopygia guttata), and diamond doves (Geopelia cuneata) to heat exposures. The birds were exposed to a temperature similar to what they experience during a typical summer day (35°C) and a higher temperature (45°C) similar to that experienced during a heat wave. There were no significant increases between the CORT concentrations before and after heat exposure in zebra finches and budgerigars at 35° and 45°C, but there was a significant increase in CORT concentrations in diamond doves after exposure to 45°C. The H∶L ratios increased significantly after heat exposure in budgerigars at 35° and 45°C and in diamond doves at 35°C. No significant correlation was found between the changes in CORT and H∶L ratios. The data suggest that there are species differences in birds' stress responses to heat exposure that may reflect their ability to detect and adapt to high temperatures. There appear to be differences between the two types of stress measurements, which may reflect differences in the timescales of these responses.

Australian birds are under threat from climate change and heatwaves. We investigated whether captive native Australian birds adjusted their time budgets, microsite selections or used thermoregulatory behaviours on typical or extremely hot summer days. We observed eight species of birds at Adelaide Zoo and found that the proportion of time spent on stationary behaviours, feeding, in the sun and on the ground differed amongst species of birds, between mornings and afternoons and day type. Wing-venting was used more frequently during the hottest observation periods. The smallest birds in the study utilised wing-venting more than other species of birds, possibly because it is more important for them to conserve water. Psittaciform birds spent less time feeding and more time resting in cooler microsites during hot periods. Columbiform birds continued feeding and spent more time in the sun rather than resting in cooler microsites. Whitebrowed Woodswallows spent a significantly lower proportion of time on stationary behaviours and a higher proportion of time feeding compared to the other species. Our results suggest that columbiform birds may have an advantage during heatwaves as they can continue feeding through high ambient temperatures, provided there is adequate access to food and water.

In avian medicine, the use of antibiotic dosing regimens based on species-specific pharmacological studies is ideal. However, due to a lack of such studies, dose extrapolation, which may cause inefficacy and toxicity, is common practice. Multiple searches were performed using the PubMed and Web of Science databases to extract relevant pharmacological studies performed in exotic avian species. The pharmacokinetics (PK), pharmacodynamics (PD), and safety data of the selected antibiotics (enrofloxacin, marbofloxacin, gentamicin, amikacin, ceftiofur, doxycycline, and amoxicillin/clavulanate) from these studies were reviewed. This review aimed to identify trends amenable for safe inter-species dose extrapolation and provide updated findings on dosing regimens that are safe and efficacious for various exotic avian species. We observed that the half-life of antibiotics appears to be shorter in the common ostrich and that amikacin may be amenable to inter-species dose extrapolation as it is safe and shows little inter-species PK and PD variation. Species-specific enrofloxacin dosing regimens that were not listed in the Exotic Animal Formulary (5th ed.) were found for Caribbean flamingos, African penguins, southern crested caracaras, common ostriches, and greater rheas. Specific dosing regimens recommended for psittacine birds (doxycycline 130 mg/kg medicated water) and ratites (PO doxycycline 2–3.5 mg/kg q12 h, PO enrofloxacin 1.5–2.5 mg/kg q12 h and IM enrofloxacin 5 mg/kg q12 h) in the formulary may not be effective in budgerigars and common ostriches, respectively. Apart from the lack of species-specific pharmacological studies, a lack of multiple dose studies was also noted.

Desert birds must cope with occasional and unpredictable heat waves, which are slowly becoming more frequent with climate change. Different orders of birds have different physiological and behavioural capacities that may aid survival during a heat wave. To date, the expression of genes related to heat exposure have not been studied across different bird orders. We hypothesised that acutely exposing native Australian birds whose natural habitat include arid environments to a high temperature (45 °C), similar to during a heat wave, would result in the upregulation of genes with protective effects against cell damage (BCL-2, VEGFA and heat shock proteins) and inflammation (interleukins), as well as the downregulation of genes involved in the coagulation pathway (fibrinogen). We used eight each of captive-bred Budgerigars (Melopsittacus undulatus), Zebra Finches (Taeniopygia guttata) and Diamond Doves (Geopelia cuneata). Four birds of each species were exposed to a temperature that was within the zone of thermal neutrality (35 °C), while the other four birds were exposed to a higher temperature (45 °C). The mRNA expression of selected genes were then measured using high-throughput qPCR platform (Fluidigm®, BioMark™). The results supported the hypothesis that acute exposure to a high temperature would result in the upregulation of heat shock protein (HSP) genes, but there was no significant upregulation of other genes with protective effects against cell damage nor genes associated with inflammation. The results also do not support the hypothesis that acute heat exposure would result in downregulation of the genes involved in the coagulation pathway in these birds. Among all the tissues that were analysed, the gastrointestinal tissue had the highest number of upregulated HSP genes, possibly indicating that this tissue requires the most protection to continue functioning. Diamond Dove organs also had the highest number of HSP genes upregulated, possibly a reflection of their ability to better protect their cells at high temperatures.