Sexual selection theory proposes that males suffer reduced immune function and increased parasitism as costs of expressing sexual signals. Life-history theory proposes that females suffer the same costs because of inherent trade-offs between reproduction and self-maintenance. Mechanistically, each theory invokes an energetic tradeoff, although few experiments have directly compared these costs ...

Reduced weight gains and feed conversions are major sources of economic losses from avian coccidiosis. Experiments were conducted to determine possible involvement of up-regulation of cyclooxygenase (COX) activity during coccidia infections that might contribute to reduced weight gain. In a series of trials, young (3 to 5 wk of age) cockerels infected with Eimeria acervulina, a duodenal parasit...

Tissue-encysting coccidia, including Toxoplasma gondii and Sarcocystis neurona, are heterogamous parasites with sexual and asexual life stages in definitive and intermediate hosts, respectively. During its sexual life stage, T. gondii reproduces either by genetic out-crossing or via clonal amplification of a single strain through self-mating. Out-crossing has been experimentally verified as a p...

A range of protistan parasites occur in the blood of vertebrates and are transmitted by haematophagous invertebrate vectors. Some 48 genera are recognized in bood primarily on the basis of parasite morphology and host specificity; including extracellular kinetoplastids (trypanosomatids) and intracellular apicomplexa (haemogregarines, haemococcidia, haemosporidia and piroplasms). Gene sequences ...

Partial (∼ 780 bp) mitochondrial cytochrome c oxidase subunit I (COI) and near complete nuclear 18S rDNA (∼ 1,780 bp) sequences were directly compared to assess their relative usefulness as markers for species identification and phylogenetic analysis of coccidian parasites (phylum Apicomplexa). Fifteen new COI partial sequences were obtained using two pairs of new primers from rigorously charac...

WE PERFORM THE FIRST MULTIDISCIPLINARY STUDY OF PARASITES FROM AN EXTINCT MEGAFAUNAL CLADE USING COPROLITES FROM THE NEW ZEALAND MOA (AVES: Dinornithiformes). Ancient DNA and microscopic analyses of 84 coprolites deposited by four moa species (South Island giant moa, Dinornis robustus; little bush moa, Anomalopteryx didiformis; heavy-footed moa, Pachyornis elephantopus; and upland moa, Megalapt...

The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found...

neurologic and psychologic complications are usually related to drug toxicity, infections or symptoms induced by deterioration of renal allograft function. metabolic encephalopathy, hypertensive encephalopathy, cerebrovascular events, and new-onset seizures have all been reported in organ-transplant recipients. infections can be caused by listeria, cryptococcus, nocardia, aspergillus and mucor....

Fecal samples were collected from 655 passerine birds representing 190 species from 13 collection sites in Guyana, Ecuador, Peru, and Argentina from August, 1990 August, 1997. The fecal samples were stored in 2.5% K2Cr2O7 and examined for coccidian oocysts within six weeks after collection. The overall prevalence of coccidian parasites in the samples was 20.9% (137/655). The one-sample test of ...