The Complexity of Zoonotic Filariasis Episystem and Its Consequences: A Multidisciplinary View
BIOMED RESEARCH INTERNATIONAL
Authors: Simon, Fernando; Gonzalez-Miguel, Javier; Diosdado, Alicia; Josefina Gomez, Paula; Morchon, Rodrigo; Kartashev, Vladimir
Abstract
Vector-borne transmitted helminthic zoonosis affects the health and economy of both developing and developed countries. The concept of episystem includes the set of biological, environmental, and epidemiological elements of these diseases in defined geographic and temporal scales. Dirofilariasis caused by different species of the genus Dirofilaria is a disease affecting domestic and wild canines and felines and man, transmitted by different species of culicid mosquitoes. This complexity is increased because Dirofilaria species harbor intracellular symbiont Wolbachia bacteriae, which play a key role in the embryogenesis and development of dirofilariae and in the inflammatory pathology of the disease. In addition, the vector transmission makes the dirofilariasis susceptible to the influence of the climate and its variations. The present review addresses the analysis of dirofilariasis from the point of view of the episystem, analyzing the complex network of interactions established between biological components, climate, and factors related to human activity, as well as the different problems they pose. The progress of knowledge on human and animal dirofilariasis is largely due to the multidisciplinary approach. Nevertheless, different aspects of the disease need to continue being investigated and cooperation between countries and specialists involved should be intensified.
INFERENCE OF POPULATION STRUCTURE AND PATTERNS OF GENE FLOW IN CANINE HEARTWORM (DIROFILARIA IMMITIS)
JOURNAL OF PARASITOLOGY
Authors: Belanger, Diana H.; Perkins, Susan L.; Rockwell, Robert F.
Abstract
Understanding the genetic variation within a parasitic species is crucial to implementing successful control programs and preventing the dispersal of drug resistance alleles. We examined the population genetics and structure of canine heartworm (Dirofilaria immitis) by developing a panel of 11 polymorphic microsatellite loci for this abundant parasite. In total, 192 individual nematodes were opportunistically sampled from 9 geographic regions in the United States and Mexico and genotyped. Population genetic analyses indicate the presence of 4 genetic clusters. The canine heartworm samples used in this study were characterized by low heterozygosity, with eastern and central North America experiencing high levels of reciprocal gene flow. Geographic barriers impede the movement of vectors and infected hosts west of the Rocky Mountains and south of the Central Mexican Plateau. This, combined with corridors of contiguous habitat, could influence the spread of drug resistance alleles.