Toxoplasma gondii, Leishmania amazonensis and Trypanosoma cruzi are obligate intracellular parasites that multiply until lysis of host cells. The present study was undertaken to evaluate the effect of hydroxyurea (an inhibitor of cell division at the G1/S phase) on the multiplication of L. amazonensis, T. gondii, and T. cruzi in infected host cells. Infected cells were treated with hydroxyurea ...

The fate of a parasite with exclusively vertical transmission depends critically on its virulence, the magnitude of its negative impact on fitness of the infected host. Relaxation of natural selection within the host population should favour the parasite by reducing this impact. We studied the dynamics of the sigma virus, a vertically transmitted parasite of Drosophila melanogaster, within a ca...

Many hosts are infected by several parasite genotypes at a time. In these co-infected hosts, parasites can interact in various ways thus creating diverse within-host dynamics, making it difficult to predict the expression and the evolution of virulence. Moreover, multiple infections generate a combinatorial diversity of cotransmission routes at the host population level, which complicates the e...

The leaves of Dendrophthoe falcata growing on different trees had differing dry solid content. With 1 exception, the parasite leaf contained less dry solid than host leaf.A characteristic feature of the loranthus parasite was the accumulation of phosphate in excess of that present in host leaves. Expressed as percent of the total phosphorus, the parasite tissue contained significantly less acid...

Mycoplasma agalactiae is the etiological agent of the contagious agalactia syndrome in sheep and goats and causes significant economic losses worldwide. Yet the mechanism of pathogenesis is largely unknown. Even whole-genome sequence analysis of its pathogenic type strain did not lead to any conclusions regarding its virulence or pathogenicity factors. Although inflammation and tissue destructi...

The emergence of new, more pathogenic viruses necessitates elucidation of factors that promote viral evolution. Aging, a potential factor, is associated with increased susceptibility to viral infections. We used the enterovirus coxsackievirus B3 (CVB3) to investigate the effects of host age on pathogenicity and viral gene sequence. Old mice infected with a normally amyocarditic strain of CVB3, ...

Host protein synthesis is inhibited in cells infected with vesicular stomatitis virus (VSV). It has been proposed that viral mRNAs are subjected to the same inhibition but are predominantly translated because of their abundance. To compare translation efficiencies of viral and host mRNAs during infection, we used an enhanced green fluorescent protein (EGFP) reporter expressed from a recombinant...

Transmission from one host to another is a crucial component of parasite fitness. For some aquatic parasites, transmission occurs via free-living stage that spends time in the water, awaiting an encounter with new host. These stages can be impacted by biotic and abiotic factors influence parasite's ability successfully infect or grow Here we tested whether spent water column and/or exposure com...