Pathogenicity of Avian Malaria in Experimentally-Infected Hawaii Amakihi

Abstract

The introduction of avian malaria (Plasmodium relictum) and mosquitoes (Culex quinquefasciatus) to the Hawaiian Islands (USA) is believed to have played a major role in the decline and extinction of native Hawaiian honeycreepers (Drepanidinae). This introduced disease is thought to be one of the primary factors limiting recovery of honeycreepers at elevations below 1,200 m where native forest habitats are still relatively intact. One of the few remaining species of honeycreepers with a wide elevational distribution is the Hawaii Amakihi (Hernignathus virens). We measured morbidity and mortality in experimentally-infected Hawaii Amakihi that were captured in a high elevation, xeric habitat that is above the current range of the mosquito vector. Mortality among amakihi exposed to a single infective mosquito bite was 65% (13/20). All infected birds had significant declines in food consumption and a corresponding loss in body weight over the 60 day course of the experiment. Gross and microscopic lesions in birds that succumbed to malaria included enlargement and discoloration of the spleen and liver and parasitemias as high as 50% of circulating erythrocytes. Mortality in experimentally-infected amakihi was similar to that observed in Apapane (Himnatione sanguinea) and lower than that observed in Iiwi (Vestiaria coccinea) infected under similar conditions with the same parasite isolate. We conclude that the current elevational and geographic distribution of Hawaiian honeycreepers is determined by relative susceptibility to avian malaria.

Avian malaria: a new lease of life for an old experimental model to study the evolutionary ecology ofPlasmodium

“…A wellknown example of the potentially devastating effects of avian malaria on host fitness is the decline and extinction of naive populations of honeycreepers after the accidental introduction of the parasite to the Hawaiian Islands in the early twentieth century [44]. Detecting fitness costs on endemic infections in the wild has, however, proved more challenging.…”

Prevalence of blood protozoa in poultry in Tangail, Bangladesh

“…Malaria parasites are supposed to have strong negative effects on host fitness because this intra-cellular parasite causes dramatic reductions in the efficiency of metabolism [15]. Ultimately, bird can lead to progressive weakness, declines in food consumption and activity levels, loss of up to 30% body weight [16] and eventually, death. [17] studied the role of blood parasites as a potential source of physiological stress for avian hosts in the wild.…”

Hemoparásitos Presentes en Poblaciones Ferales de la Paloma de Castilla (Columba livia) en el Departamento de Lima, Perú

“…Esta enfermedad está relacionada con hemosporidios de múltiples linajes de los Plasmodium sp (especialmente P. relictum) y Haemoproteus sp. La patogenicidad de la enfermedad ha sido estudiada experimentalmente en varias especies de aves (Atkinson et al, 2000), hacién-dose más evidente en aves con infecciones agudas y aves cautivas en zoológicos. Los impactos más significativos de estos parási-tos pueden ser patologías subclínicas e indirectas, pudiendo afectar su desarrollo y capacidad reproductiva (Lapointe et , seguido de Plasmodium sp con 29.4% y Leucocytozoon sp con 15.7% (Scaglione et al, 2015).…”