South African National Parks

The anatomy and function of tactile structures, such as vibrissae, are typically studied in captive animals, but we know little about how tactile structures compare between captive and wild animals. We analyzed trunk tip morphology in wild (n = 6) and captive (n = 6) adult African savanna elephants (Loxodonta africana). We found striking differences in both vibrissae and skin structure between the two groups. Wild elephants showed significant vibrissae abrasion, with frontal trunk tip vibrissae often entirely worn down, whereas captive elephants retained proportionally more long vibrissae, particularly along the trunk tip rim. In wild elephants, vibrissae rarely exceeded 1 cm in length, whereas many captive individuals had vibrissae several centimeters long. In contrast, vibrissae inside the nostril—a trunk region not directly exposed to feeding—were similar in length and density between wild and captive elephants. Additionally, trunk tip skin in wild elephants appeared to be worn down to a smooth surface, whereas all captive elephants showed distinct papillary skin structure and folds at the lateral trunk tip opening and nasal septum. These findings suggest that wild elephants experience feeding-related trunk abrasion, leading to significant alterations in both vibrissa structure and skin texture. Our results highlight the importance of studying sensory structures in wild animals to understand sensing in natural environments.

The prevalence and diversity of Anaplasma in common warthog (Phacochoerus africanus) was investigated using a multi-locus sequence analysis (MLSA) approach targeting the 16S rRNA, citrate synthase (gltA) and heat-shock operon (groESL) genes. PCR screening of 100 warthog samples from the Kruger National Park in South Africa with eight published assays identified 50 positive animals, all of which were initially identified with the 16S rRNA assay. In contrast, the gltA and six groESL assays recovered PCR-positivity rates of 2 % and 0 %-4 %, respectively. As optimisation did not improve Anaplasma detection rates, an alternative groESL assay targeting a 923 bp region was designed. This new assay detected 45 positive animals, all of which were positive with the 16S rRNA assay. Nucleotide sequencing of the three MLSA gene targets confirmed that 50 % (50/100) of warthogs were Anaplasma-positive. Juvenile warthogs displayed a significantly higher infection rate (15/18; 83.3 %) than adults (35/82; 42,68 %). Phylogenetic analyses of individual and concatenated gene datasets confirmed that the Anaplasma species in warthogs is closely related to the species detected in Ornithodoros soft ticks from Zambia. This, together with the high levels of nucleotide sequence identity (≥98.97 %), suggests the likely existence of a host-restricted cycle involving warthogs and the soft ticks that inhabit their burrows. Based on the distinctiveness and monophyly of the Anaplasma species in warthogs and Ornithodoros soft ticks, confirmed through genetic characterisation of three gene regions, we propose that Candidatus status be assigned and suggest "Candidatus Anaplasma ornithodorii".

Understanding immune responses to infectious diseases, such as tuberculosis (TB), is essential for developing diagnostic tests and studying disease progression. Although TB affects African savanna elephants (Loxodonta africana), few studies have investigated immune cells and function in this species, especially in the respiratory tract. Techniques for isolating immune cells from elephant bronchoalveolar lavage (BAL) samples have not been previously reported. Therefore, this study aimed to develop and optimise a protocol to isolate and characterise alveolar cell types in BAL fluid collected from free-ranging, African savanna elephants. The optimised protocol incorporated a mucin digestion step, filtration, Ficoll gradient separation and wash steps to remove contaminants and successfully isolate viable populations of alveolar mononuclear cells. The isolated cells were stained with Rapi-Diff and microscopically examined to differentiate and characterise each cell type present. Cells isolated from healthy African elephant BAL samples, using this method, were predominantly alveolar macrophages (92.5 - 100.0 %) followed by lymphocytes (0.0 - 6.0 %), neutrophils (0.0 - 3.0 %) and eosinophils (0.0 - 1.0 %). This study provides the first optimised protocol for the isolation of alveolar mononuclear cells for future investigations into local immune responses to respiratory diseases such as tuberculosis.