[Detection of Rickettsia typhi in Rhipicephalus sanguineus s.l. and Amblyomma mixtum in South of Mexico]. / Detección de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum en el sur de México.

OBJECTIVE: To determine the presence of Rickettsia typhi in Rhipicephalus sanguineus s.l. and Amblyomma mixtum in southern Mexico. MATERIALS AND METHODS: Ticks were collected in humans and domestic animals. The presence of Rickettsia was determined by PCR and sequencing. RESULTS: 10/39 work vials amplified fragments of the gltA, htrA and ompB genes. On 7/10 from Rh. sanguineus s.l. collected from dogs and in 3/10 of A. mixtum collected from horse and human. Sequencing indicated R. typhi in Rh. sanguineus and A. mixtum with 100% homology (LS992663.1) for a region of the htrA gene and 99% (LS992663.1) with the regions of the gltA and OmpB genes. The minimum infection rate (TMI) for R. typhi was 3.88. CONCLUSIONS: Rhipicephalus sanguineus s.l. and Amblyomma mixtum are naturally infected with R. typhi in Southern Mexico.

OBJETIVO: Determinar la presencia de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum, en el sur de México. MATERIAL Y MÉTODOS: Las garrapatas fueron colectadas en humanos y animales domésticos. Se determinó la presencia de Rickettsia por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés) y secuenciación. RESULTADOS: 10/39 viales de trabajo amplificaron fragmentos de los genes gltA, htrA y ompB, en 7/10 proveniente de Rh. sanguineus s.l. colectadas de perros y en 3/10 de A. mixtum colectadas de caballo y humano. La secuenciación indicó R. typhi en Rh. sanguineus y A. mixtum con homología de 100% (LS992663.1), para una región del gen de htrA, y de 99% (LS992663.1), con las regiones de los genes de gltA y OmpB. La tasa mínima de infección (TMI) para R. typhi fue de 3.88. CONCLUSIONES: Las garrapatas Rhipicephalus sanguineus s.l. y Amblyomma mixtum están infectadas naturalmente con R. typhi en el sur de México.

Single­nucleotide polymorphisms in the promoter of the gene encoding for C­reactive protein associated with acute coronary syndrome.

Acute coronary syndrome (ACS) is a leading cause of mortality worldwide. Several studies have shown that certain single nucleotide polymorphisms (SNPs) are linked to the development of ACS. In particular, C-reactive protein (CRP) has emerged as an important predictive biomarker for cardiovascular disease. The current study aimed to investigate four polymorphisms of the CRP gene as possible biomarkers for ACS in a sample of 252 individuals (114 patients with ACS and 138 healthy controls) from Southeastern Mexico. Multivariate analysis adjusted for clinical variables showed that the polymorphism 3872CT for the genotype CC/CT [adjusted Odds Ratio (AdOR)=3.78; 95% Confidence Interval (CI): 1.11-12.92; P=0.034] and the genotype GG/GC of the polymorphisms 2667CG (AdOR=4.82; 95% CI: 1.69-13.72; P=0.02) were associated with ACS. However, the polymorphisms 3006AC genotype AA/AC and 5237GA genotype GG/GC were not found to be associated in the multivariate analysis with ACS (P>0.05). These results suggested that 3872CC/CT and 2667CC/CG polymorphism of the CRP gene plays a significant role in the development of ACS.

Dog hair volatiles attract Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) females.

Rhipicephalus sanguineus sensu lato (s.l.) (Latreille) feeds on domestic dogs worldwide. This tick species uses dog volatiles during host-seeking behavior. In this study, we identified volatile compounds from dog hairs involved in the host location of R. sanguineus s.l. The R. sanguineus s.l. females, but not males, were attracted to hair samples and Super Q extracts from Schnauzer dogs in Y-tube olfactometer bioassays. A total of 54 compounds from dog hair extracts were identified by gas chromatography coupled to mass spectrometry, including hydrocarbons, aldehydes, alcohols, ketones, and carboxylic acids. Screening the identified compounds by the single sensillum recording technique showed that isovaleric acid, hexanal, heptanal, and sucaltone (6-methyl-5-hepten-2-one) significantly stimulated the olfactory receptor neurons of the basiconic, chaeticum, and trichodeum sensilla of female ticks. When synthetic compounds were evaluated alone, or in binary, tertiary, or quaternary mixtures, female ticks were only attracted to isovaleric acid and 1 tertiary mixture (hexanal, heptanal, and isovaleric acid). We conclude that isovaleric acid functions as an attractant for R. sanguineus s.l. These findings contribute to the understanding of the chemical ecology of ticks during host location.

Detección de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum en el sur de México / Detection of Rickettsia typhi in Rhipicephalus sanguineus s.l. and Amblyomma mixtum in South Mexico

Resumen: Objetivo: Determinar la presencia de Rickettsia typhi en Rhipicephalus sanguineus s.l. y Amblyomma mixtum, en el sur de México. Material y métodos: Las garrapatas fueron colectadas en humanos y animales domésticos. Se determinó la presencia de Rickettsia por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés) y secuenciación. Resultados: 10/39 viales de trabajo amplificaron fragmentos de los genes gltA, htrA y ompB, en 7/10 proveniente de Rh. sanguineus s.l. colectadas de perros y en 3/10 de A. mixtum colectadas de caballo y humano. La secuenciación indicó R. typhi en Rh. sanguineus y A. mixtum con homología de 100% (LS992663.1), para una región del gen de htrA, y de 99% (LS992663.1), con las regiones de los genes de gltA y OmpB. La tasa mínima de infección (TMI) para R. typhi fue de 3.88. Conclusiones: Las garrapatas Rhipicephalus sanguineus s.l. y Amblyomma mixtum están infectadas naturalmente con R. typhi en el sur de México.

Abstract: Objective: To determine the presence of Rickettsia typhi in Rhipicephalus sanguineuss.l. and Amblyomma mixtum in southern Mexico. Materials and methods: Ticks were collected in humans and domestic animals. The presence of Rickettsia was determined by PCR and sequencing. Results: 10/39 work vials amplified fragments of the gltA,htrA and ompB genes. On 7/10 from Rh. sanguineus s.l collected from dogs and in 3/10 of A. mixtum collected from horse and human. Sequencing indicated R. typhi in Rh. Sanguineus and A. mixtum with 100% homology (LS992663.1) for a region of the htrA gene and 99% (LS992663.1) with the regions of the gltA and OmpB genes. The minimum infection rate (TMI) for R. typhi was 3.88. Conclusions: Rhipicephalus sanguineuss.l. and Amblyomma mixtum are naturally infected with R. typhi in Southern Mexico.