Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors

Abstract

The African penguin (Spheniscus demersus) is a critically endangered species endemic to southern Africa. Limited information is available on the parasite diversity associated with the species in natural settings. This study explores the diversity and incidence of parasites associated with African penguins and their nests, and records the effect of host and environmental factors on parasite infestation. Ecto-, haemo- and helminth parasites were recorded from 210 adult birds, 583 chicks and 628 nests across five colonies (two mainland and three islands) along the south-western coast of South Africa, in 2016 and 2017. Mean nest density (total and active nests) and climate variables (temperature and precipitation) were obtained for each colony. Parapsyllus humboldti was the most abundant and prevalent ectoparasite on penguins and in nests (69.10 and 57.80%, respectively), while Piroplasmorida/Haemospororida (33.51%) and Cardiocephaloides spp. (56.17%) were the most prevalent haemo- and helminth parasites of penguins, respectively. In general parasite abundance and prevalence was significantly affected by penguin age (chicks vs adults), location (mainland vs islands), nest density (total and active nests) and season (spring vs autumn/winter). It is concluded that parasite infestations are structured and that penguin chicks at mainland colonies are more susceptible to parasite infestations during spring.

Nest-type associated microclimatic conditions as potential drivers of ectoparasite infestations in African penguin nests

“…The higher soil temperature and moisture in active nests than non-active nests may be attributed to the heat and moisture radiation from the host's body and faeces (Rothschild and Clay 1952;Marshall 1981). Active nests also harboured higher flea infestations, which is consistent with the intimate relationship between fleas and hosts (Bitam et al 2010;Espinaze et al 2019b). Flea larvae indirectly benefit from nest occupancy as their diet includes host organic refuse (Rothschild and Clay 1952).…”

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

“…The prevalence of external parasites in this study was remarkably higher than that reported for wild African penguins at the Western Cape (Table 3). In part, this may be related to the fact that our sample largely corresponded to penguins from mainland colonies, which are known to have a higher prevalence of fleas, ticks and Babesia / Plasmodium than island colonies (Espinaze et al ., 2019). Perhaps more significantly, however, the generally higher prevalence of parasites seen in this study might be related to the fact that our sample consisted of individuals that were brought for rehabilitation.…”

“…Blood parasites were remarkably common in African penguins examined in this study, with Babesia being the most frequent (46% prevalence on admission, 72% infection ratio), whereas Borrelia was recorded only sporadically (1% prevalence on admission, 3% infection ratio) and Plasmodium was only recorded once. Although these parasites have long been known to infect wild African penguins (Coles, 1941; Fantham and Porter, 1944), their prevalence in this study was markedly higher than in apparently wild healthy adult African penguins sampled in previous studies (Parsons et al ., 2016; Espinaze et al ., 2019).…”

“…Although several studies have investigated the ecology and negative effects that external parasites can have on penguins, most studies focused on hard ticks (Ixodidae) (Gauthier-Clerc et al ., 1998, 2003; Frenot et al ., 2001; Benoit et al ., 2007, 2009; Jansen van Rensburg, 2010; Barbosa et al ., 2011), and few have investigated the factors driving the ecology and health effects of soft ticks (Argasidae), fleas (Siphonapthera) and lice (Phthiraptera) on penguins (Duffy and Daturi, 1987; González-Acuña et al ., 2013; Espinaze et al ., 2019). Three species of external parasites are known to infect wild African penguins: the fleas Parapsyllus longicornis humboldti and Echidnophaga gallinacea , the soft tick Ornithodoros capensis and the chewing louse Austrogoniodes demersus (Von Keler, 1952; Zumpt, 1959; Beaucournu and Rodhain, 1990; Espinaze et al ., 2019). The tick O. capensis is suspected to transmit blood parasites to African penguins, such as the piroplasmid protozoan Babesia peircei (Earlé et al ., 1993), the spirochete bacterium Borrelia sp.…”

“…A recent study found that penguin age group (chick vs adult), colony location (mainland vs island), nest density (total and active nests) and season (spring vs autumn/winter) were significant factors determining the abundance of fleas and ticks and the prevalence of blood parasites in wild African penguins at colonies in the Western Cape, South Africa (Espinaze et al ., 2019). In this study, we investigate the occurrence of external and blood parasites in African penguins admitted at a rehabilitation centre in the same region, and evaluate whether their prevalence and abundance differ from those reported in wild African penguins and which factors of the individual history of these birds may influence the infection by different external and blood parasites.…”