Landscape heterogeneity shapes host-parasite interactions and results in apparent plant-virus codivergence.

Knowledge on how landscape heterogeneity shapes host-parasite interactions is central to understand the emergence, dynamics and evolution of infectious diseases. However, this is an underexplored subject, particularly for plant-virus systems. Here, we analyse how landscape heterogeneity influences the prevalence, spatial genetic structure, and temporal dynamics of Pepper golden mosaic and Pepper huasteco yellow vein begomoviruses infecting populations of the wild pepper Capsicum annuum glabriusculum (chiltepin) in Mexico. Environmental heterogeneity occurred at different nested spatial scales (host populations within biogeographical provinces), with levels of human management varying among host population within a province. Results indicate that landscape heterogeneity affects the epidemiology and genetic structure of chiltepin-infecting begomoviruses in a scale-specific manner, probably related to conditions favouring the viruses' whitefly vector and its dispersion. Increased levels of human management of the host populations were associated with higher virus prevalence and erased the spatial genetic structure of the virus populations. Also, environmental heterogeneity similarly shaped the spatial genetic structures of host and viruses. This resulted in the congruence between host and virus phylogenies, which does not seem to be due to host-virus co-evolution. Thus, results provide evidence of the key role of landscape heterogeneity in determining plant-virus interactions.

[Bilateral infundibula in congenital cardiopathies]. / Infundíbulos bilaterales en cardiopatías congénitas.

The goal of this paper has been to count and describe congenital heart disease associated with double conus. We studied 196 pathologic specimens from to the Pathologic Collection of the Department of Embryology of the National Institute of Cardiology "Ignacio Chávez" of México. We found 3% of double conus in classic tricuspid atresia with concordant ventriculoarterial connection, 53% with double outlet right ventricle, 16% with discordant ventriculoarterial connection, 91% with double outlet single ventricle, 8% with one outlet right ventricle with pulmonary atresia, 20% with one outlet left ventricle and 25% with one outlet single ventricle. The morphological data of the associated anomalies were gathered in an informatized sheet designed according the segmental and sequential approach to diagnose congenital heart disease. From our results we conclude that double conus cannot be considered pathognomonic of any congenital cardiopathy, although they appear associated more frequently with truncoconal anomalies and single ventricle. It is frequent the association between double conus and stenosis of one of them, specially the subpulmonary one. We found great association between left juxtaposition of the atrial appendages and double conus.

[Absence of the tricuspid valve. A case report]. / Ausencia de la válvula tricúspide. Informe de un caso.

An anatomical embryological and histological study of a malformed heart is presented in which the right concordant atrioventricular connexion is unguarded by the tricuspid valve, due to absence of the three leaflets, chordae tendinae and papillary muscles; only the fibrous ring is present in the atrioventricular junction. This very rare malformation is associated with atresia of the valve connected with the right ventricle generally being the pulmonary valve; the ventricular septum is intact. This congenital lesion always present fibrosis in the free wall of the right ventricle. We believe a primary pathogenetic step occurs in the wall of the right ventricle which prevents the morphogenesis of the tricuspid valve from this ventricle. This malformation must be distinguish from Ebstein's disease and Uhl's disease, although they are pathogenetically related.

[The pathological remnants of the right sinus venosus valve. A presentation of 6 hearts of the cor tritriatum dexter type]. / Derivados patológicos de la valva derecha del seno venoso. Presentación de seis corazones de tipo cor triatriatum dextrum.

Six hearts specimens of cor triatriatum dextrum, eight with the Chiari's network, and 3 with a membranous remnant of the crista terminalis are studied. These anomalies are interpreted as varying degrees of persistence of the right valve of the sinus venous which reflect different stages of their morphogenesis. The most frequent congenital heart defects associated with these sinus remnants are the absence of a right atrioventricular connexion and pulmonary atresia with intact ventricular septum. There may be some haemodynamic factors in the right atrium such as partial of complete obstruction between the atrium and the right ventricle which explain the fact that the valve is not reabsorbed. In our specimens the persistent right valve divided the right atrium into two compartments; one is located in the medial sinusal portion where both cavae veins and coronary sinus are connected; the other is lateral compartment which represents the primitive right atrium. It must be noted that the persistent right valve favors blood flow to the left atrium through the patent foramen ovale or through an atrial septal defect deviating the course of the blood away from the right ventricle. This could cause the hypoplasia of the right ventricle. When the valve bulges it obstructs the blood flowing into the right ventricle. The diagnosis of these malformations can be made by echocardiographic, angiocardiographic procedures and nuclear magnetic resonance.

[Rheumatic cardiopathy in children younger than 6 years of age]. / Cardiopatía reumática en niños menores de 6 años.

UNLABELLED: Most of the published papers on Rheumatic Fever (RF) have not included the younger population. We selected 211 cases of children with RF younger than 6 years of age from 9,471 clinical files from 1944 to 1982. These were followed retrospectively to identify the presence of rheumatic activity, subsequent attacks and penicillin profilaxis. From de 211 cases, 209 had carditis; 57% of them were girls and 43% boys. There were no previous infections of the upper respiratory tract in 36% of the patients. The number of cases with RF increased abruptly after 3 years of age and continued increasing until 5 years of age when 70.5% of the population had there first clinically recognized attack. Lesions were present in the mitral valve in 80% of the cases, in the aortic valve in 12%, in the tricuspid in 5% and in the pulmonary valve in 3%. The death rate during the first attack was 20% being refractory heart failure the main cause of death. Thirteen cases suffered rheumatic pneumonia, 9 of whom died (69.2%). CONCLUSIONS: 1) The incidence of acute rheumatic fever in children under 6 years of age has decreased with time. 2) The death rate as well as the valvular damage decreased with the parents cooperation with the treatment. 3) The changes in the clinical picture and the severity of valve sequelea may be due to penicillin profilaxis and the better understanding of the disease.