Paradoxical effects of coupling infectious livestock populations and imposing transport restrictions.

Spatial heterogeneity of a host population of mobile agents has been shown to be a crucial determinant of many aspects of disease dynamics, ranging from the proliferation of diseases to their persistence and to vaccination strategies. In addition, the importance of regional and structural differences grows in our modern world. Little is known, though, about the consequences when traits of a disease vary regionally.

Discriminating the effects of spatial extent and population size in cyclic competition among species.

We introduce a population model for species under cyclic competition. This model allows individuals to coexist and interact on single cells while migration takes place between adjacent cells. In contrast to the model introduced by Reichenbach, Mobilia, and Frey [Reichenbach, Mobilia, and Frey, Nature (London) 448, 1046 (2007)], we find that the emergence of spirals results in an ambiguous behavior regarding the stability of coexistence.

Canine leishmaniasis: identification of asymptomatic carriers by polymerase chain reaction and immunoblotting.

A major limitation to the study of the epidemiology of canine visceral leishmaniasis is the inability to identify and count asymptomatic carriers because classic diagnositc tests are insufficiently sensitive. We investigated the capacity of the polymerase chain reaction (PCR) to detect the parasite and immunoblotting to detect specific antibodies in samples from dogs living in an endemic area without any symptoms of leishmaniasis. Results of classic serologic tests (immunofluorescence and enzyme-linked immunosorbent assay) were negative.

Characterization of a circulating antigen involved in immune complexes in visceral leishmaniasis patients.

Complications of visceral leishmaniasis are explained in part by immune complex pathology, particularly nephritis. Using the polyethylene glycol precipitation method, we identified among these complexes a Leishmania infantum circulating antigen by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Monoclonal antibodies were produced to specifically detect this antigen.

Western blot analysis of antibodies to Leishmania infantum antigens: potential of the 14-kD and 16-kD antigens for diagnosis and epidemiologic purposes.

When infected with Leishmania species, patients develop specific antibodies that constitute the basis of serodiagnosis. Using Western blot analysis, we studied the specificity of anti-L. infantum antibodies in patients with visceral leishmaniasis (including patients with acquired immunodeficiency syndrome [AIDS]) and in healthy subjects living in an endemic area.