Determinants of external and blood parasite load in African penguins (Spheniscus demersus) admitted for rehabilitation

Abstract

We investigate the factors associated with the occurrence and abundance of external and blood parasites in African penguins (Spheniscus demersus), an endangered seabird that breeds exclusively on the coasts of Namibia and South Africa. External parasites were collected using the dust-ruffling method from 171 African Penguins admitted at a rehabilitation facility in the Western Cape, South Africa. Additionally, blood smears were obtained upon admission and weekly during rehabilitation and examined for blood parasites. Fleas Parapsyllus longicornis humboldti, ticks Ornithodoros capensis and lice Austrogoniodes demersus were recovered from 93, 63 and 40%, respectively, of the penguins upon admission to the centre. Rescue location and age group were identified as significant determinants of flea abundance, whereas month of admission was a significant determinant of tick abundance. Blood parasites were also common on admission, with Babesia being the most frequent (46% prevalence) whereas Borrelia was recorded sporadically (1.2%) and Plasmodium was recorded once. The prevalence and abundance of ticks on admission was positively associated with Babesia infection on admission. Our findings demonstrate the variability and contributing factor of parasite infections in an endangered species of penguin, and highlight the need for additional research on the parasite–host dynamics involving these potential disease vectors.

Potential Role of Avian Populations in the Epidemiology of Rickettsia spp. and Babesia spp.

“…Argasidae, mostly Ornithodoros seem to be involved in Babesia transmission in colonial birds nesting on ground or near rocks, whose crevices would represent breeding sites for these invertebrate hosts. The occurrence of Ornithodoros capensis on African penguins seems to be strongly related with Babesia infection higly supporting the hypothesis that this tick would be the main vector of the parasites [50,51]. These findings have been corroborated by the occurrence of Babesia DNA in this argasid species from New Zealand too [52].…”

A soft tick vector of Babesia sp. YLG in Yellow-legged gull (Larus michahellis) nests

“…The parasite reservoir may consist in Babesia infected ticks, surviving in the soil around the nests during the non-breeding period, or in infected adult gulls, or both. The prevalence of Babesia infected seabirds and parasite loads in the blood are usually lower in adults compared to chicks (Quillfeldt et al, 2014;Espinaze et al, 2019;Snyman et al, 2020), so the role of adult birds as reservoirs may be limited. However, further analyses of adult gulls are required, as many studies only use blood smears to detect blood parasites, a method that lacks the sensitivity required to detect asymptomatic carriers (Malandrin et al, 2004;Chauvin et al, 2009).…”

First Report of Polymelia in a Passerine Bird, the Pied Flycatcher

“…Unlike in other animals, polymelia has not been commonly observed in birds. So far, it has been reported among broiler chickens and other farming fowls (Abu-Seida 2014, Hassanzadeh & Rahemi 2017, Plang et al 2021, Snyman et al 2022. The only cases reported in wild birds are the Swainson's Hawk Buteo swainsoni (Rogers et al 2016) and the White Stork Ciconia ciconia (Onmuş 2017).…”