Health evaluation of African penguins (Spheniscus demersus) in southern Africa.

Nola J Parsons,Tertius A Gous,Ralph E.T Vanstreels,Adam M Schaefer

doi:10.4102/ojvr.v83i1.1147

Abstract

The African penguin (Spheniscus demersus) is an endangered seabird that breeds along the coast of Namibia and South Africa, and disease surveillance was identified as a priority for its conservation. Aiming for the establishment of baseline data on the presence of potential pathogens in this species, a comprehensive health assessment (blood smear examination, haematology, biochemistry and serology) was conducted on samples obtained from 578 African penguins at 11 breeding colonies and a rehabilitation centre. There were 68 penguins that were seropositive for at least one of seven pathogens tested: avian encephalomyelitis virus, avian infectious bronchitis virus, avian reovirus, infectious bursal disease virus, Newcastle disease virus, Mycoplasma gallisepticum and Mycoplasma synoviae. All samples were seronegative for avian influenza virus subtypes H5 and H7 and infectious laryngotracheitis virus. The apparent prevalence of Babesia sp. and Borrelia sp. in blood smears was consistent with previous studies. Babesia-infected individuals had a regenerative response of the erythrocytic lineage, an active inflammatory response and hepatic function impairment. These findings indicate that African penguins may be exposed to conservation-significant pathogens in the wild and encourage further studies aiming for the direct detection and/or isolation of these microorganisms.

Highlights

The African penguin (Spheniscus demersus) is considered an endangered species (BirdLife International 2015) that breeds from central Namibia to South Africa’s Eastern Cape Province (Hockey, Dean & Ryan 2005) (Figure 1)
Samples tested for antibodies against Mycoplasma spp. using serum plate agglutination (SPA) were more frequently positive (4.2% for Mycoplasma gallisepticum (MG) and 8.1% for Mycoplasma synoviae (MS)) than those tested using enzyme-linked immunosorbent assay (ELISA) (0.5% for both MG and MS); this occurred for both MG (p < 0.01) and MS (p = 0.03)
Blood smears revealed 33 samples were positive for Babesia sp., 2 individuals were positive for Borrelia sp. and 1 individual was positive for both Babesia sp. and Borrelia sp. (Table 2); no other blood parasites were observed

Summary

Introduction

The African penguin (Spheniscus demersus) is considered an endangered species (BirdLife International 2015) that breeds from central Namibia to South Africa’s Eastern Cape Province (Hockey, Dean & Ryan 2005) (Figure 1). The levels of breeding success were deemed inadequate to sustain the African penguin population, and among other conservation efforts, limiting mortality through controlling the spread of disease was suggested to try to maintain an equilibrium situation (Crawford et al 2006). Disease is a major ecological force that has the potential to cause significant effects especially in threatened populations (Friend, McLean & Dein 2001) and Heard et al (2013) showed that the threat of disease increases with the level of extinction risk in all species. There is limited knowledge on the effects of disease on population dynamics of seabirds (Lewison et al 2012) or even for the role of disease as a major threat to species at risk of extinction (Heard et al 2013). While a single disease outbreak could decimate a population, the true cost of disease may be associated with chronic attrition of the population (Friend et al 2001) and thereby influence metabolic rate, life history traits and social status (Barbosa & Palacios 2009)

Methods

Results

Discussion

Conclusion