Examinando por Autor "Howerth, E."
Mostrando 1 - 2 de 2
Resultados por página
Opciones de ordenación
Ítem Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures(eLife Sciences Publications Ltd, 2018-11) Seguel, M.; Montalva, F.; Perez-Venegas, D.; Gutiérrez, J.; Paves, H.J.; Müller, A.; Valencia-Soto, C.; Howerth, E.; Mendiola, V.; Gottdenker, N.Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal. © Seguel et al.Ítem The life history strategy of a fur seal hookworm in relation to pathogenicity and host health status(Australian Society for Parasitology, 2018) Seguel, M.; Muñoz, F.; Perez-Venegas, D.; Müller, A.; Paves, H.; Howerth, E.; Gottdenker, N.The strategies that parasites use to exploit their hosts can lead to adverse effects on human and animal populations. Here, we describe the life cycle, epidemiology, and consequences of hookworm (Uncinaria sp.) disease in South American fur seals (Arctocephalus australis), and propose that hookworm adaptation to fur seal life history traits has led to maximizing transmission at high levels of parasite-induced anemia and mortality. Fur seal pups acquire hookworms during their first days of life through their mothers’ colostrum and most adult hookworms are expelled from the pups’ intestine 30–65 days later. This gives hookworms little time to feed and reproduce. However, despite reaching high within-host densities, female hookworms do not decrease egg output, therefore pups with high hookworm burden contribute disproportionately to parasite egg shedding. These heavily infected pups also suffer severe anemia and high levels of hookworm-induced mortality. Alternative strategies to maximize total egg shedding and/or transmission, such as increased environmental survival of larval stages or avoidance of clearance, have not been developed by this hookworm. We propose that fur seal hookworms exploit a live fast-die young life history strategy, which translates to the highest levels of host anemia and mortality recorded among hookworms. © 2018