Species-specific plasmid sequences for PCR identification of the three species of Borrelia burgdorferi sensu lato involved in Lyme disease.

Species-specific sequences were shown to be carried by plasmids of the three main species of Borrelia burgdorferi sensu lato involved in Lyme disease. Libraries of the 16-, 33-, and 25-kb plasmids of B. burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, respectively, were then built and used to isolate species-specific sequences. After sequencing of the cloned inserts, three sets of primers were designed. They were shown to determine species-specific PCR amplification products. The sensitivities of the PCR assay with these primers were 100 spirochetes for B. burgdorferi sensu stricto and 1,000 spirochetes for B. garinii and B. afzelii. The usefulness of these primers for the identification of species in biological samples (tick, serum, and cerebrospinal fluid samples) was ascertained

Cloning and expression of portions of the 34-kilodalton-protein gene of Mycobacterium paratuberculosis: its application to serological analysis of Johne's disease.

Paratuberculosis (Johne's disease), an endemic mycobacteriosis of cattle that is caused by Mycobacterium paratuberculosis, is characterized by incoercible diarrhea and fecal shedding of bacteria. The present work aimed at developing a specific serological test for this disease. We have recently shown that a 34-kDa protein belonging to the major antigen complex A36 of M. paratuberculosis is immunodominant and contains epitopes specific with respect to all mycobacteria tested, including Mycobacterium bovis and the closely related species Mycobacterium avium. From a lambda gt11 genomic library of M. paratuberculosis, three portions of the gene coding for this 34-kDa protein have been isolated. Two of them expressed cross-reacting mycobacterial epitopes. One portion (in clone a362) expressed a polypeptide which cross-reacted with all tested M. paratuberculosis strains but not with 20 other bacteria tested, including many strains of the M. avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum group. The occurrence at the M. paratuberculosis surface of epitopes corresponding to the a362 polypeptide was shown by immune electron microscopy. The recombinant a362 polypeptide was used as reagent for an enzyme-linked immunoassay for paratuberculosis. This assay correctly diagnosed all the tested blood samples from infected cattle at all stages of the disease

Cloning and sequencing of a species-specific nucleotide fragment of Borrelia burgdorferi sensu stricto, which is repeated in several plasmids of the species.

Among the etiological agents of Lyme disease, Borrelia burgdorferi sensu stricto strains carry a 16 kb plasmid, which did not hybridize to plasmids of B. garinii and B. afzelii strains. A 1271 bp DNA fragment of the 16 kb plasmid was cloned. It hybridized to several plasmids of this species (16, 27 and 55 kb). Sequencing of the cloned insert revealed a 327 bp ORF coding for a 14 kDa protein of unknown function, which could be expressed in E. coli. This ORF, conserved among B. burgdorferi sensu stricto strains, was carried by the same three plasmids

A cytotaxonomic approach of the systematics of Arvicanthis niloticus

Arvicanthis niloticus (Desmarest 1822) (Mammalia Rodentia) exhibits different karyotypes in different populations throughout its wide distribution area, characterized by diploid numbers ranging from 2n = 62 to 56. A 44 chromosome karyotype is described in one A. niloticus from Somalia. The taxonomic and evolutionary inferences are discussed

Individual and environmental factors associated with the seroprevalence of Borrelia burgdorferi

Background: Lyme disease (LD) is a common tick-borne disease in Europe. Diverse factors at various scales determine the spatial distribution of Borrelia burgdorferi infection risk and a better understanding of those factors in a spatially explicit framework is needed for disease management and prevention. While the ecology of ticks and the landscape favoring their abundance have been extensively studied, the environmental conditions favoring an intense contact with susceptible humans, including groups at risk, are sparse. The aim of this study is to assess which individual and environmental factors can favor B. burgdorferi infection in a Belgian group professionally at risk. Methods: Serological results of 127 veterinarians and farmers enrolled in this study were analyzed, taking into account their municipality of residence. Using binary logistic regression and considering interaction terms, the joint effects of landscape composition and configuration, and forest and wildlife management were examined. Results: Seven of the 127 workers were seropositive for LD, leading to a seroprevalence of 5.51%. Seropositivity was higher in older persons. The proportion of forest and semi-natural habitats and wetland had a positive impact on LD seroprevalence while arable land–grassland ecotones had a negative one. Our results confirmed the need to consider complex interactions between landscape variables in order to model risk. Conclusions: Our data show that LD has to be considered as a risk for farmers and veterinarians. Rather than focusing either on ecological aspects of tick and pathogen distribution or on purely epidemiological aspects such as individual risk factors, our model highlights the role of human–environment interactions in LD risk assessment