First report of systemic toxoplasmosis in a New Zealand sea lion (Phocarctos hookeri)

Abstract

Infection with T. gondii involving the spinal cord and nerves was the likely cause of the paresis observed in this sea lion before death. Ultimately, death was attributed to crushing and asphyxiation by a male sea lion, presumably predisposed by impaired mobility. Diagnosis of toxoplasmosis in a New Zealand sea lion highlights the possibility that this disease could play a role in morbidity and mortality in this endangered species, particularly in the recently established mainland populations that are close to feline sources of T. gondii oocysts.

Polyphasic Rhabdomyositis in California Sea Lions (Zalophus Californianus): Pathology and Potential Causes

“…11,23,27,35 In marine mammals, myositis has been sporadically reported in cetaceans and pinnipeds, and infectious agents such as Clostridium perfringens, Toxoplasma gondii, Sarcocystis neurona, and Klebsiella pneumoniae are some of the reported causes. 1,3,6,28,30 However, in most of these cases, muscle inflammation is secondary to systemic infection, which primarily targets other organs and tissues, and pathogens that only affect the muscle of marine mammals have been rarely reported. 1,5 For more than a decade, a myopathy syndrome has been recognized in California sea lions (CSLs; Zalophus californianus) stranded along the central California coast.…”

“…Myositis has been described in a wide range of wild avian and mammalian species. 23,28,35 Similar to domestic animals, many inflammatory myopathies of wildlife have a traumatic, nutritional, toxic or infectious origin with the relevance of each of those factors depending on the animal species, habitat and biology of the studied populations. 11,23,27,35 In marine mammals, myositis has been sporadically reported in cetaceans and pinnipeds, and infectious agents such as Clostridium perfringens , Toxoplasma gondii, Sarcocystis neurona , and Klebsiella pneumoniae are some of the reported causes.…”

Causes of adult mortality in two populations of New Zealand sea lions (Phocarctos hookeri)

“…Five Enderby Island conspecific deaths were opportunistically observed, and all involved mating attempts by adult males, including three attacks in shallow water which resulted in drowning/asphyxiation. Five cases had concurrent conditions considered likely to have contributed to death: one with toxoplasmosis (previously described in detail in Roe et al. (2017) ), three with severely infected bite wounds, and one with bacterial septicaemia.…”

“…A mass mortality event on Enderby Island in 1998 caused the death of at least 74 adults, characterised by neck abscesses and attributed to a pleomorphic gram negative bacillus that could not be cultured ( Baker, 1999 ). There are several reports of mortality investigations in individual adult sea lions from mainland New Zealand, including infections due to toxoplasmosis ( Roe et al., 2017 ) and tuberculosis ( Roe, PJ, L, GW, & DV, 2006 ).…”

Toxoplasma gondii seroprevalence in the endangered Australian sea lion (Neophoca cinerea)

“…In the marine mammals, the former can contribute directly to illness or death from localized or disseminated infection, reported for instance in the California sea lion (Zalophus californianus) (Carlson-Bremer et al, 2015), Mediterranean monk seal (Monachus monachus) (Mazzariol et al, 2021) and multiple other seal species (van de Velde et al, 2016;Reisfeld et al, 2019). Additionally, infection can increase the risk of death from other causes such as predation and conspecific trauma, as observed in the southern sea otter (Kreuder et al, 2003) and New Zealand sea lion (Phocarctos hookeri) (Roe et al, 2017). Transplacental transmission, placental inflammation and disseminated congenital fetal infection, resulting in early or late-term abortion or stillbirth have also been documented in multiple species, among them Risso's dolphin (Grampus griseus) (Resendes et al, 2002), the California sea lion (Carlson-Bremer et al, 2015) and the southern sea otter (Shapiro et al, 2016).…”