Detection and characterization of a novel spotted fever group Rickettsia genotype in Haemaphysalis leporispalustris from California, USA.

The rabbit tick, Haemaphysalis leporispalustris Packard, is known for its association with Rickettsia rickettsii as it harbors both virulent and avirulent strains of this pathogen. In this manuscript we report findings and preliminary characterization of a novel spotted fever group rickettsia (SFGR) in rabbit ticks from California, USA. Rickettsia sp. CA6269 (proposed "Candidatus Rickettsia lanei") is most related to known R. rickettsii isolates but belongs to its own well-supported branch different from those of all R. rickettsii including strain Hlp2 and from Rickettsia sp. 364D (also known as R. philipii) and R. peacockii. This SFGR probably exhibits both transovarial and transstadial survival since it was found in both questing larvae and nymphs. Although this rabbit tick does not frequently bite humans, its role in maintenance of other rickettsial agents and this novel SFGR warrant further investigation.

The Eco-epidemiology of Pacific Coast Tick Fever in California.

Rickettsia philipii (type strain "Rickettsia 364D"), the etiologic agent of Pacific Coast tick fever (PCTF), is transmitted to people by the Pacific Coast tick, Dermacentor occidentalis. Following the first confirmed human case of PCTF in 2008, 13 additional human cases have been reported in California, more than half of which were pediatric cases. The most common features of PCTF are the presence of at least one necrotic lesion known as an eschar (100%), fever (85%), and headache (79%); four case-patients required hospitalization and four had multiple eschars. Findings presented here implicate the nymphal or larval stages of D. occidentalis as the primary vectors of R. philipii to people. Peak transmission risk from ticks to people occurs in late summer. Rickettsia philipii DNA was detected in D. occidentalis ticks from 15 of 37 California counties. Similarly, non-pathogenic Rickettsia rhipicephali DNA was detected in D. occidentalis in 29 of 38 counties with an average prevalence of 12.0% in adult ticks. In total, 5,601 ticks tested from 2009 through 2015 yielded an overall R. philipii infection prevalence of 2.1% in adults, 0.9% in nymphs and a minimum infection prevalence of 0.4% in larval pools. Although most human cases of PCTF have been reported from northern California, acarological surveillance suggests that R. philipii may occur throughout the distribution range of D. occidentalis.

Seasonal activity patterns of the western black-legged tick, Ixodes pacificus, in relation to onset of human Lyme disease in northwestern California.

Seasonal activity patterns of questing western black-legged ticks, Ixodes pacificus were investigated in northwestern California. Adult I. pacificus became active in the fall (late October/early November) and their appearance was associated with the first rain of the season. Following a peak in January, the abundance of adult ticks declined such that they were rare or absent by June/July. The nymphal tick activity season occurred from January through October, and larval activity occurred from April to June, but sometimes extended into October. Thus, potentially infectious ticks (nymphs and adults) present a year-round risk of Lyme disease transmission in northwestern California. The seasonality of Lyme disease cases in humans, based on the onset of erythema migrans, mirrored tick activity patterns and was year-round in cases infected in California. Peak incidence in humans occurs from May through July, and indicates that most disease transmission is from nymphal ticks. This study demonstrates that tick activity patterns are more extended than previously recognized in northwestern California.

Vertebrate hosts of Ixodes pacificus (Acari: Ixodidae) in California.

The western black-legged tick, Ixodes pacificus Cooley & Kohls, is an important parasite and vector of disease agents that affect human and animal health in the western United States. This paper presents a review of all published California host records for I. pacificus. Unpublished data from public health, academic, and vector control agencies and researchers were reviewed as well. Host species were identified for each active life stage (larvae, nymph and adult). A total of 108 vertebrate species in three classes (Mammalia, Aves, and Reptilia) were identified as hosts for at least one life stage of I. pacificus. Adult I. pacificus were recorded from 29 species of mammals, 2 species of birds, and 1 reptile species. Nymphal I. pacificus were recorded from 30 species of mammals, 38 species of birds, and 8 reptile species. Larval I. pacificus were recorded from 29 species of mammals, 43 species of birds, and 8 species of reptiles. A table depicting the taxonomic classification of host species is provided. This review adds eight new host records to the California list of recognized vertebrate host species for I. pacificus.

[The influence of health education on nutrition]. / Evaluación de la influencia de la educación sanitaria en la alimentación.

To assess the effectiveness of health education in relation to the changes it produces in both information and the general population's outlook on food consumption. DESIGN. A controlled intervention study, with a randomized double-blind sample. PLACE. Village covered by the Fuenlabrada Health Centre. PARTICIPANTS. 88 families agreed to take part, out of the 408 that made up the total sample for the field study on food consumption previously undertaken. 24 families in the intervention group (46% loss) and 35 in the control group (20% loss) completed the study. ACTIVITY. A group of nurses with diplomas in Health Education delivered advice and instruction on diet and health to the families in the study group, during April, May and June, 1990. MEASUREMENTS AND MAIN RESULTS. Two kinds of questionnaires, both previously validated, were used to measure the varying levels of food consumption and of information. These questionnaires were filled by both sample groups (intervention and control), before and after the health education. The level of knowledge, taking into account the number of positive answers in the information questionnaire, was significantly higher in the intervention group than in the control one (p less than 0.005). The level of food consumption was significantly higher in the meat intervention group, attaining an average of 3.08 (2.46-3.67); whereas in the control group an average of 4.39 was obtained. (3.72-5.06) (p less than 0.005). CONCLUSIONS. There was scant participation among the healthy population.(ABSTRACT TRUNCATED AT 250 WORDS)