This is the first study on the distribution and occurrence of Helicosporidium sp. in the populations of the great spruce bark beetle Dendroctonus micans (Coleoptera: Curculionidae, Scolytinae) from different localities. Two hundred and eight of 2300 examined beetles were infected by Helicosporidium sp. In total infection rate was 9.04%. The infection reached 71.7%. The prevalence of Helicospori...

The relationship between host size and infection, the site selection in the host and the association between health status and infection were studied in Hexamita salmonis (Moore, 1923) infected rainbow trout from commercial trout farms. During a 1 yr survey it was shown that the flagellates occur primarily In the smallest fry. The site occupied by the parasite is preferentially the pyloric regi...

Morphological evidence has been obtained by electron microscopy in support of previous findings that one of the most important functions of sialidase is associated with the release of virus from infected host cells. Highly specific antiserum against fowl plague virus enzyme and specific antiserum against X7 recombinant influenza virus enzyme were shown to influence the morphology of cells infec...

We have established a long-term culture system to study macrophages chronically infected with mycobacteria. Monocytes are infected with Bacillus Calmette-Guerin (BCG) and support exponential intracellular replication without profound perturbation of normal host cell function. We have used this system to investigate lymphokine-activated killer (LAK)-mediated cytolysis. We have found that interle...

The balance between the products of L-arginine metabolism in macrophages regulates the outcome of Leishmania major infection. L-arginine can be oxidized by host inducible NO synthase to produce NO, which contributes to parasite killing. In contrast, L-arginine hydrolysis by host arginase blocks NO generation and provides polyamines, which can support parasite proliferation. Additionally, Leishm...

Here we describe, determine the prevalence, and examine the host-specificity of some parasitic nematode microfilariae in selected bird species from West and Central Africa. We used microscopy to determine the prevalence of microfilariae in 969 host individuals representing 121 rainforest bird species from Cameroon, Côte d'Ivoire and Equatorial Guinea. Thirteen (11%) of these potential host spec...

One of the conditions that can affect host susceptibility and parasite transmission is the occurrence of concomitant infections. Parasites interact directly or indirectly within an individual host and often these interactions are modulated by the host immune response. We used a free-living rabbit population co-infected with the nematode Trichostrongylus retortaeformis, which appears to stimulat...

Signals modulating the production of Mycobacterium tuberculosis (Mtb) virulence factors essential for establishing long-term persistent infection are unknown. The WhiB3 redox regulator is known to regulate the production of Mtb virulence factors, however the mechanisms of this modulation are unknown. To advance our understanding of the mechanisms involved in WhiB3 regulation, we performed Mtb i...

Plasmodium falciparum gametocytes modify the mechanical properties of their erythrocyte host to persist for several weeks in blood circulation and be available mosquitoes. These changes are tightly regulated by plasmodial phosphodiesterase delta that decreases both stiffness permeability infected cell. Here, we address effect inhibitor tadalafil on deformability gametocyte-infected erythrocytes...

members of erysiphales cause powdery mildew diseases on wide host rang and produce whitish primary mycelium on surface of infected parts. based on microscopic study of one specimen on jasminum sp., structures of fungus including conidiophores and conidia were observed. foot cells of conidiophores were cylindrical or curved in basal part, followed by 1-2 shorter cells. conidia were ellipsoid to ...