Brown Dog Tick (Rhipicephalus sanguineus Sensu Lato) Infection with Endosymbiont and Human Pathogenic Rickettsia spp., in Northeastern México.

Of the documented tick-borne diseases infecting humans in México, Rocky Mountain spotted fever (RMSF), caused by the Gram-negative bacterium Rickettsia rickettsii, is responsible for most fatalities. Given recent evidence of brown dog tick, Rhipicephalus sanguineus s.l., as an emerging vector of human RMSF, we aimed to evaluate dogs and their ticks for rickettsiae infections as an initial step in assessing the establishment of this pathosystem in a poorly studied region of northeastern México while evaluating the use of dogs as sentinels for transmission/human disease risk. We sampled owned dogs living in six disadvantaged neighborhoods of Reynosa, northeastern México to collect whole blood and ticks. Of 168 dogs assessed, tick infestation prevalence was 53%, composed of exclusively Rh. sanguineus s. l. (n = 2170 ticks). Using PCR and sequencing, we identified an overall rickettsiae infection prevalence of 4.1% (n = 12/292) in ticks, in which eight dogs harbored at least one infected tick. Rickettsiae infections included Rickettsia amblyommatis and Rickettsia parkeri, both of which are emerging human pathogens, as well as Candidatus Rickettsia andeanae. This is the first documentation of pathogenic Rickettsia species in Rh. sanguineus s.l. collected from dogs from northeastern México. Domestic dog infestation with Rickettsia-infected ticks indicates ongoing transmission; thus, humans are at risk for exposure, and this underscores the importance of public and veterinary health surveillance for these pathogens.

DNA barcoding of blackflies (Diptera: Simuliidae) as a tool for species identification and detection of hidden diversity in the eastern regions of Spain.

BACKGROUND: Blackflies have negative impact on public and animal health due to the haematophagous habit of females. In recent times, in some regions in Spain, blackfly outbreaks are becoming more and more frequent, threatening the public health. However, there is still a paucity of data concerning the Spanish blackfly fauna. Correct identification of species is of paramount importance in order to provide correct information on species distribution, biology and behaviour, so that control measures could be implemented appropriately. METHODS: Blackflies specimens (larvae, pupae, reared adults and biting females) were collected in the period 2015-2017 in and near rivers and streams from different regions in Spain. A modified Hotshot technique was used for the DNA extraction and the cox1 DNA barcoding region of the cytochrome c oxidase subunit 1 was sequenced from the specimens collected. RESULTS: In total, we collected 239 specimens representing 22 species. Of these, six species are new records for the Aragón region: P. tomosvaryi, S. bertrandi, S. galloprovinciale, S. lineatum, S. rubzovianum and S. xanthinum. Cox1 DNA barcode sequences for 21 species were recovered, including four species of the genus Prosimulium and 17 species of the genus Simulium [Boophthora (1 species), Eusimulium (1 species), Nevermannia (4 species), Simulium (s.s.) (6 species), Trichodagmia (1 species) and Wilhelmia (4 species)]. For the first time the complete DNA barcodes for five species (P. tomosvaryi, S. carthusiense, S. brevidens, S. monticola and S. sergenti) were registered. Most of the specimens belonging to the same recognized species were clustered together in the neighbour-joining tree, except for S. argyreatum, S. monticola and S. variegatum. The overall genetic distance in the dataset was 0.14%. The average of the intraspecific genetic divergence within the different taxa was 1.47% (0.05-3.96%). In contrast, the interspecific divergence varied between 2.50-22.0%. CONCLUSIONS: In this study we assessed the use of the cox1 DNA barcoding region for the identification of species of blackflies in Spain. Our results showed that combining DNA barcoding with morphology enhanced our taxonomic rationale in identifying the blackflies in the country.

Isolation of Bdellovibrio sp. from soil samples in Mexico and their potential applications in control of pathogens.

In this study, two strains of Bdellovibrio were isolated from soil samples using the culture-dependent technique and two members of the family Enterobacteriaceae (Klebsiella sp. and Salmonella sp.) as prey. The Bdellovibrio strains were bacteriolytic, plaque-forming, and highly motile gram-negative bacteria. We identified and confirmed the Bdellovibrio strains using microscopy, PCR amplification, and sequencing of the 16S rRNA gene. They were observed to be different strains based on hit locus and prey range analyses. Here, the first report on Bdellovibrio strains isolated from soil in Mexico corroborates earlier report indicating that populations of Bdellovibrio found in soil are heterogeneous thereby the need to identify the various strains.

Algunos problemas en la investigación para el control de la transmisión de Ochocerca volvulus en México / Research for the control of the transmission of Onchocerca volvulus in Mexico

El tratamiento y control de la oncocercosis en México ha sustentado desde su inicio en la eliminación de las microfilarias con el uso de la dietilcarbamazina y la extirpación quirúrgica de los oncocercomas que arrojan los gusanos adultos. Estas medidas al parecer han disminuido la prevalencia e incidencia de la ceguera en aquellos individuos afectados por esa parasitosis. Sin embargo, no se ha logrado un impacto importante sobre la transmisión de la oncocercosis en México el control químico del vector ha tenido buenos resultados en otras regiones del mundo; en México, sin embargo no ha sido plenamente aceptado como parte integral del control de la oncocercosis por diversas causas. Más aún, pocas investigaciones se han realizado en relación a la búsqueda de nuevas alternativas para el control del vector. Recientemente, el resultado de investigaciones sobre la invermectina (agente microfilaricida) mostraron que esta droga es eficaz y segura para el tratamiento de la oncocercosis. En otros reportes se ha señalado tambien que la ivermectina tiene un efecto sobre la transmisión de esta filaria. No obstante, existen algunas interrogantes acerca de su capacidad para suspender la transmisión de la oncocercosis, discutiendo los problemas para su diagnóstico, tratamiento y control. Además se propone el empleo de parámetros para la evaluación correcta de las medidas de control, con énfasis en las determinaciones entomológicas

The treatment and control of onchocerciasis in Mexico has been supported only on the administration of diethy carbamazine and the removal of adult worms, which are in the onchocercomata. These actions seems to have diminished the prevalence and incidence of blindness in those individuals who are affected by this parasitosis. However, there has not been an important impact on onchocerciasis transmission. The objective of this paper is to critically analyze and discuss subjects related to diagnosis, treatment and control of onchocerciasis transmission in Mexico. Chemical vector control has been successfully archieved in other world regions; however, in Mexico, it has not been fully acepted as part of the integral onchocerciasis control due to several causes. Moreover, there has been few scientific research activties toward the search of new options for vector control. Recently, results of research on ivermectin (a microfilaricide agent) have indicated that this drug is effective and safe for the treatment of onchocerciasis. Additionally, it has been reported that ivermectin has an effect on the onchocerciasis transmission. However, there are several unanswered questions about the efficacy of ivermectin in toping onchocerciasis transmission. In this report, the ain efforts carried out in Mexico against onchocerciasis are analysed and problems related with diagnosis, treatment and control are also discussed Some parameters for the correct evaluation of onchocerciasis control, with entomological emphasis, are proposed.