Seropositivity rates for agents of canine vector-borne diseases in Spain : a multicentre study

Background: Controlling canine vector-borne diseases (CVBD) is a major concern, since some of these diseases are serious zoonoses. This study was designed to determine seropositivity rates in Spain for agents causing the following five CVBD: leishmaniosis (Leishmania infantum: Li), heartworm (Dirofilaria immitis: Di), ehrlichiosis (Ehrlichia canis: Ec), anaplasmosis (Anaplasma phagocytophilum/Anaplasma platys: An) and Lyme disease (Borrelia burgdorferi: Bb). Methods: Anti-An, -Bb, and -Ec antibodies and the Di antigen were determined using the 4DX SNAP® Test (IDEXX Laboratories) and anti-L. infantum (Li) antibodies using the Leishmania SNAP® Test (IDEXX Laboratories) in blood and/or serum samples. Results: Among 1100 dogs examined, overall seropositivity rates were: Li (15.7%), Ec (5%), An (3.1%), Di (1.25%) and Bb (0.4%). While seropositivity towards Bb and Di was similar in all geographic regions, rates were significantly higher in the east of Spain (8.3%) for An, significantly higher in the north (20%) for Ec, and significantly higher in the Southeast (46.6%) and South (27.4%), and significantly lower in the north (0%) for Li. No statistical associations were observed between sex and the CVBD analyzed (p ≥ 0.05) while the following associations with other variables were detected: a higher seropositivity to Ec (40%) and Bb (6.7%) in dogs under one year of age compared with adults (p < 0.05); and a higher seropositivity to An and Li in dogs that lived outdoors versus indoors (p = 0.01; p < 0.001, respectively). Seropositivity rates of 2.1%, 0%, 1.7%, 0.5% and 4.2% were recorded respectively for An, Bb, Ec, Di and Li in dogs with no clinical signs (n = 556) versus 3.8%, 0.6%, 7.5%, 1.8% and 25.9% for those with signs (n = 507) suggestive of a CVBD. Conclusion: The data obtained indicate a risk for dogs in Spain of acquiring any of the five CVBD examined. Veterinarians in the different regions should include these diseases in their differential diagnoses and recommend the use of repellents and other prophylactic measures to prevent disease transmission by arthropod vectors. Public health authorities also need to become more involved in the problem, since some of the CVBD examined here also affect humans

Galectin and aldolase-like molecules are responsible for the specific IgE response in humans exposed to Dirofilaria immitis

Dirofilaria immitis is the agent of the heartworm disease in canids and felids, and of pulmonary dirofilariosis in man. Like other filariae, D. immitis harbours endosymbion Wolbachia bacteriae. In this work we analyse the response of specific IgE antibodies against both D. immitis antigens and the Wolbachia surface protein (WSP) in two groups of persons living in an area of canine endemia, one presenting high levels of total IgE (group 1) and other with normal levels (group 2). Infections with D. immitis were demonstrated by the presence of specific IgG in 228 individuals(48.8%) of the group 1 and only in one of the group 2. Specific IgE antibody response against D. immitis antigens was detected only in individuals of the group 1. IgE response against WSP was not detected in any group. The IgE response was directed mainly against two molecules of 33 and 42 kDa of the antigenic extract of D. immitis. These molecules were identified by mass spectrometry as a galectin and an aldolase, respectively. Their possible role in the survival mechanisms of the parasite and their contribution to development of allergic reactions in individuals resident in areas with heartworm disease are discussed. © 2008 The Authors

Stage-specific proteomic expression patterns of the human filarial parasite Brugia malayi and its endosymbiont Wolbachia

Global proteomic analyses of pathogens have thus far been limited to unicellular organisms (e.g., protozoa and bacteria). Proteomic analyses of most eukaryotic pathogens (e.g., helminths) have been restricted to specific organs, specific stages, or secretomes. We report here a large-scale proteomic characterization of almost all the major mammalian stages of Brugia malayi, a causative agent of lymphatic filariasis, resulting in the identification of more than 62% of the products predicted from the Bm draft genome. The analysis also yielded much of the proteome of Wolbachia, the obligate endosymbiont of Bm that also expressed proteins in a stage-specific manner. Of the 11,610 predicted Bm gene products, 7,103 were definitively identified from adult male, adult female, blood-borne and uterine microfilariae, and infective L3 larvae. Among the 4,956 gene products (42.5%) inferred from the genome as “hypothetical,” the present study was able to confirm 2,336 (47.1%) as bona fide proteins. Analysis of protein families and domains coupled with stage-specific expression highlight the important pathways that benefit the parasite during its development in the host. Gene set enrichment analysis identified extracellular matrix proteins and those with immunologic effects as enriched in the microfilarial and L3 stages. Parasite sex- and stage-specific protein expression identified those pathways related to parasite differentiation and demonstrates stage-specific expression by the Bm endosymbiont Wolbachia as well