Molecular and pathogenic characterization of Borrelia burgdorferi sensu lato isolates from Spain.

Fifteen Borrelia burgdorferi sensu lato isolates from questing ticks and skin biopsy specimens from erythema migrans patients in three different areas of Spain were characterized. Four different genospecies were found (nine Borrelia garinii, including the two human isolates, three B. burgdorferi sensu stricto, two B. valaisiana, and one B. lusitaniae), showing a diverse spectrum of B. burgdorferi sensu lato species. B. garinii isolates were highly variable in terms of pulsed-field gel electrophoresis pattern and OspA serotype, with four of the seven serotypes described. One of the human isolates was OspA serotype 5, the same found in four of seven tick isolates. The second human isolate was OspA serotype 3, which was not present in ticks from the same area. Seven B. garinii isolates were able to disseminate through the skin of C3H/HeN mice and to cause severe inflammation of joints. One of the two B. valaisiana isolates also caused disease in mice. Only one B. burgdorferi sensu stricto isolate was recovered from the urinary bladder. One isolate each of B. valaisiana and B. lusitaniae were not able to disseminate through the skin of mice or to infect internal organs. In summary, there is substantial diversity in the species and in the pathogenicity of B. burgdorferi sensu lato in areas in northern Spain where Lyme disease is endemic.

[Tick-borne recurrent fever. Description of 5 cases]. / Fiebre recurrente transmitida por garrapatas. Descripción de 5 casos.

BACKGROUND: Tick-borne relapsing fever (FRGT) is a worldwide zoonosis. The disease is caused by spirochetes of the genus Borrelia, and is transmitted to man by ticks of the genus Ornithodoros (O. erraticus in Spain). METHODS: 5 FRTG cases attended in our hospital in a 2 years period are described. Diagnosis was established in all cases by demonstration of borreliae in peripheral blood. Three Borrelia strains were isolated from blood of 3 of our patients and they are maintained by passages through mice. RESULTS: High fever, tachycardia and headache were noted in all cases accompanied in 2 of them by hepatosplenomegaly. Three of the patients complained of arthromyalgias or lumbar myalgia. Treatment with doxycicline was curative in all of them. CONCLUSIONS: FRGT incidence in our country is probably underestimated due to the low suspicion of the disease and the specificity of the clinical symptoms. The isolement of the causative Borrelia strain will allow the development of more specific serological tests necessary to establish the prevalence of this disease as well to assess its implication in chronic diseases, as is observed in other borreliosis (i.e. Lyme disease), that might be missed at this moment.

A laboratory model of canine leishmaniasis: the inoculation of dogs with Leishmania infantum promastigotes from midguts of experimentally infected phlebotomine sandflies.

Twenty-five dogs (beagles) were infected with Leishmania infantum by the intradermal inoculation of an estimated 5-8,000 metacyclic promastigotes harvested from the midguts of 320 experimentally infected P. perniciosus. Details are given of the methods of infecting the flies and harvesting the parasites. All dogs developed small, self-healing chancres at the sites of inoculation. Parasites were isolated from lymph nodes, bone marrow or spleen of 21 dogs, 12 of which developed signs of disease and raised IFAT litres to Leishmania. Nine of the 21 remained healthy over a five-year observation period. Six of the nine were shown to have a cell mediated immune response to Leishmania. No parasites were isolated from four of the 25 dogs, two of which had a demonstrable cell mediated immunity and another had low transitory IFAT titres. The fourth had chancres at the sites of inoculation. The results show that dogs can be readily infected with promastigotes from the midguts of sandflies. However, a high proportion develop a cell mediated immunity and show on signs of disease. It is suggested that serological surveys of dogs for canine leishmaniasis reveal neither the true prevalence of infection nor the intensity of transmission. The efficacy of controlling human visceral leishmaniasis caused by L. infantum by destroying seropositive dogs is questioned.

Epidemiology of canine leishmaniasis: prevalence, incidence and basic reproduction number calculated from a cross-sectional serological survey on the island of Gozo, Malta.

Assessment of the resilience of canine leishmaniasis to control or, more ambitiously, the effort needed to eradicate infection, requires an estimate of the basic case reproduction number (R0). This paper applies the theoretical results of Hasibeder, Dye & Carpenter (1992) to data from a cross-sectional survey on the Maltese island of Gozo in which dogs of known age, sex and occupation (pet, guard etc) were subjected to three different serological tests for the presence of specific antibody (IFAT, DAT and ELISA). Difficulties in interpreting these test results, and hence of determining the proportion of dogs infected, present the main obstacle to estimating R0: estimates are critically dependent on the choice of threshold separating seropositives from seronegatives. The data do, however, allow a robust comparative analysis of risk which shows that the force of infection experienced by working dogs is about three times higher than that of pet dogs, a degree of non-homogeneous contact which actually has little effect on estimates of R0. We suggest a cautious point estimate of R0 congruent to 11, and comment briefly on its significance for leishmaniasis control.