First molecular detection of Rickettsia felis in fleas from Algeria.

Fleas collected in Algeria in the district of Oran between July and September 2003 were tested by polymerase chain reaction for the presence of Rickettsia spp. DNA using primers amplifying gltA and OmpA genes. Two gltA sequences identical to those of an emerging pathogen, Rickettsia felis, were detected including i) R.

Experimental infection models of ticks of the Rhipicephalus sanguineus group with Rickettsia conorii.

Rhipicephalus sanguineus group ticks collected on dogs in Thailand were maintained in the laboratory over several generations to test methods to infect these ticks with Rickettsia conorii, the agent of Mediterranean spotted fever. Three methods were tested: (1) infection of adults and nymphs through artificially induced bacteremic rabbit, (2) capillary feeding of solution containing 5 x 10(3) and 5 x 10(5)pfu/mL of R. conorii to adult female ticks, and (3) immersion of engorged nymphs which were "one leg-cut," "two leg-cut," or "cuticle cut" in solution containing R.

Transcriptional response of Rickettsia conorii exposed to temperature variation and stress starvation.

Rickettsia conorii is an obligate intracellular bacterium transmitted to humans by Rhipicephalus sanguineus ticks. The success of this microorganism at surviving in nature implicates the ability to efficiently adapt to different environments, including the arthropod vector and the mammalian host. Numerous bacterial species possess a highly evolved system for stress adaptation.

Distribution of 'Ehrlichia walkeri' in Ixodes ricinus (Acari: Ixodidae) from the northern part of Italy.

The prevalence of 'Ehrlichia walkeri' in Ixodes ricinus in northern Italy was studied. A total of 456 ticks were collected from seven places around Belluno, and 292 living ticks were examined using polymerase chain reaction (PCR). Nineteen ticks were positive for gltA of 'E.

Molecular survey of Babesia infection in dogs in Okinawa, Japan.

A total of 80 free-roaming dogs on Okinawa Island, Japan, were examined for Babesia infection using the polymerase chain reaction (PCR) and sequence analysis. Of 80 samples, 12 were positive in a Babesia genus-specific PCR. Consequent species-specific PCR for B.

Effects of salivary gland extract from Rhipicephalus sanguineus on IgG subclass production and cytokine mRNA expression in mononuclear cells of canine peripheral blood.

The effects of salivary gland extract (SGE) from R. sanguineus were examined on the production of IgG1 and IgG2 and the mRNA expression of IFN-gamma, IL-2, IL-4, IL-5 and IL-10 in the mononuclear cells from canine peripheral blood, treated with concanavalin A (ConA) in vitro. SGE suppressed the ConA-induced production of IgG2.

Demonstration of Anaplasma (Ehrlichia) platys inclusions in peripheral blood platelets of a dog in Japan.

A free-roaming dog in Okinawa island showed Anaplasma (Ehrlichia) platys-like inclusions within the platelets of peripheral blood samples. The inclusions were positive in indirect fluorescence test with anti-A. phagocytophila serum.