Highly abundant bacteria in the gut of Triatoma dimidiata (Hemiptera: Reduviidae) can inhibit the growth of Trypanosoma cruzi (Kinetoplastea: Trypanosomatidae).

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a zoonosis primarily found in rural areas of Latin America. It is considered a neglected tropical disease, and Triatoma dimidiata is the main vector of the parasite in Central America. Despite efforts, Chagas disease continues to be a public health concern, and vector control remains a primary tool to reduce transmission. In this study, we tested the hypothesis that highly abundant bacteria in the gut of T. dimidiata inhibit the growth of T. cruzi. To achieve this, bacterial diversity in the gut of T. dimidiata specimens from Costa Rica was characterized by metabarcoding of the 16S rRNA, microbial isolation was performed, and the effect of freeze-dried supernatants of the isolates on T. cruzi was investigated. Metabarcoding showed that the most abundant genera in the gut were Corynebacterium, Tsukamurella, Brevibacterium, and Staphylococcus. Barcoding and sequences comparison confirmed that 8 of the 30 most abundant amplicon sequence variants (ASVs) were isolated, and 2 of them showed an inhibitory effect on the growth of T. cruzi epimastigotes. These bacteria correspond to isolates of Tsukamurella and Brevibacterium, which were respectively the second and sixth most abundant ASVs in the gut of T. dimidiata. Notably, only the isolate of Brevibacterium showed a significant difference in growth inhibition against epimastigotes of both T. cruzi strains tested. These findings suggest that the gut microbiota of T. dimidiata may play an active role in modulating parasite development.

Detection of Rickettsia spp. in ticks of wildlife fauna from Costa Rica: First report of Rickettsia rhipicephali in Central America.

In the past two decades, new species of Rickettsia have been detected and described worldwide, some of them considered pathogenic for humans. Although Costa Rica is considered a biodiversity hotspot, the knowledge about rickettsiae in sylvatic ecosystems and wild animals is scarce. The aim of this preliminary study was to detect and identify species of Rickettsia in ticks collected from wild animals in Costa Rica. A total 119 ticks were collected from 16 animal host species belonging to diverse vertebrate families (Didelphidae, Procyonidae, Felidae, Choloepodidae, Bradypodidae, Myrmecophagidae, Tayassuidae, Tapiridae, Phyllostomidae, Bufonidae, Geoemydidae, Boidae, Colubridae), and they were grouped into 43 pools to detect the presence of Rickettsia spp. DNA by PCR targeting the gltA gene. In positive pools, amplicons of the ompA, sca5 (ompB), and/or htrA genes were also amplified to identify the species present. The identification of some ticks was also confirmed by molecular methods. Four species of Rickettsia were detected in eight (19%) tick pools: Rickettsia amblyommatis in four pools of Amblyomma geayi (host: Caluromys derbianus) and one pool of Amblyomma cf. parvum (host: Nasua narica), Rickettsia rhipicephali in one pool of Dermacentor latus (host: Tayassu pecari), 'Candidatus Rickettsia colombianensi' in one pool of Amblyomma sp. nymphs (host: Boa constrictor), and Rickettsia sp. genotype IbR/CRC in one pool of Ixodes cf. boliviensis (host: Puma concolor). This is the first molecular detection of R. rhipicephali in Central America, and of 'Candidatus R. colombianensi' in Costa Rica. Results show that diverse wild animals and their ticks are associated with several species of rickettsiae in Costa Rica, which may come in contact with humans and other domestic animals in sylvatic environments.

Acknowledging extraordinary women in the history of medical entomology.

Throughout history, women have been actively involved in the advancement of science, while struggling to overcome challenges to participate and a lack of recognition. Prior to 1950, most women were not included in the lists of "classical" descriptions of the iconic scientific figures nor included in the most relevant historical accounts. Since the second half of the twentieth century, great efforts have been made to recognize the contributions of women to the advancement of science, especially since formal scientific careers have been dominated by men, with limited (or no) access to women. Despite these challenging social, political and cultural contexts, many women have succeeded in making significant advancements, and their contributions are now being acknowledged. Such efforts have led to the publication of recent reviews and compilations on outstanding women in biological sciences. The field of medical entomology is inherently interdisciplinary, focusing on insects and other arthropods that affect human health, with input primarily from the biological and medical sciences and a strong public health perspective. Several reviews and book chapters describing the history of medical entomology have been published over the decades, but few women are mentioned in these publications, even though many women have contributed to this field. Much of the information on these women is currently scattered throughout the published literature and historical records on a wide range of topics, including activism, virology, vector control and even acarology. Considering that there is no single available compilation of women contributors in the history of medical entomology, this review aims to provide a list of 22 women and their contributions to this field. The list includes women from diverse backgrounds, born in the late 1800s and before 1950, who directly impacted medical entomology in various ways and in different regions of the world. This compilation is far from exhaustive, but it aims to identify role models and examples of extraordinary women to motivate the evolving future of this field.

Cimex lectularius Linnaeus, 1758 (Hemiptera: Cimicidae) in Costa Rica: First Case Report Confirmed by Molecular Methods in Central America.

Cimex lectularius and Cimex hemipterus are the most common species of bedbugs that infest homes. Although case reports decreased substantially by the end of the 20th century, bed bugs, and especially C. lectularius, are currently suffering a resurgence mostly attributed to insecticide resistance, inadequate pest control, and increased travel. Here, we report, to the best of our knowledge, the first molecular confirmation of C. lectularius in Central America. Specimens were obtained from an apartment located in Heredia, Costa Rica. These specimens were identified morphologically as C. lectularius. The species identification was confirmed by amplifying and sequencing fragments of the cytochrome oxidase subunit I (COI) and the 16S rRNA (16S) genes. The phylogenetic analysis showed that the sequences obtained were more closely related to a C. lectularius mitochondrial complete genome sequence from China, with similarities of 98.84% (686/694) for COI and 98.97% (387/391) for 16S. The finding of C. lectularius in Costa Rica will require further investigation in order to determine the extent of current infestations and the susceptibility to insecticides, especially due to the impact that this species can have in human health, as well as the tourism industry in the region.

Papel potencial de Aedes albopictus Skuse en la transmisión de virus dengue (DENV) en una zona de actividad piñera de Costa Rica

RESUMEN Objetivo: Evaluar, bajo una perspectiva ecológica, la presencia de Aedes albopictus y su infección natural por virus dengue (DENV) en una zona de actividad piñera de Costa Rica. Método: Se colectaron mosquitos adultos en galerías forestales colindantes con piñeras, viviendas en proximidad a cultivos (<1 km) y viviendas en lejanía (110 km). Se empleó el índice de Shannon-Wiener para estimar biodiversidad. La infestación larvaria se evaluó en plantas de piña y viviendas y se calcularon índices aédicos de viviendas (IV) y de contenedores (IC). La detección de DENV en adultos (cuerpos y cabezas) y en larvas de Ae. albopictus se efectuó mediante RT-PCR y secuenciación. Resultados: Se colectaron 1376 adultos en total: Ae. albopictus (5,81%), Anopheles apicimacula (5,01%), Culex coronator (11,55%), Cx. inflictus (6,1%), Cx. nigripalpus (48,11%), Cx. quinquefasciatus (23,34%) y Limatus durhamii (0,07%). El índice de biodiversidad fue mayor en galerías forestales. Ae. albopictus adultos fueron colectados principalmente en el área de piñeras (73/80), aunque sólo dos larvas en las plantas de piña. Los índices aédicos en proximidad (IV: 40,7%, IC: 26,9%) y en lejanía (IV: 51,7%, IC: 29,6%) no mostraron diferencias significativas (IV Z=0,56, p=0,58; IC Z=0,16, p=0,87). Se detectó DENV-2 y DENV-3 en 2/20 grupos de cabezas y DENV-1 en 2/74 grupos de larvas de Ae. albopictus. Discusión: Las galerías forestales próximas a cultivos de piña podrían considerarse "islas ecológicas" adecuadas para el refugio de Ae. albopictus. La presencia de DENV en adultos y larvas sugiere un papel activo de Ae. albopictus en la transmisión de virus en este ecosistema.

ABSTRACT Objective To evaluate, under an ecological perspective, the presence of Aedes albopictus and the wild infection by dengue viruses (DENV) in an area of pineapple activity in Costa Rica. Materials and methods Adult mosquitoes were collected in forest galleries limiting pineapple plantations, houses adjacent to plantations (<1 km), and distant houses (1-10 km). Shannon-Wiener index was used to estimate biodiversity. Larval infestation was evaluated in pineapple plants and houses, and aedic house (HI) and container (CI) indices were calculated. Detection of DENV in Ae. albopictus adults (bodies and heads) and larvae was performed by RT-PCR and sequencing. Results A total 1376 adult mosquitoes were collected: Ae. albopictus (5.81%), Anopheles apicimacula (5.01%), Culex coronator (11.55%), Cx. inflictus (6.1%), Cx. nigripalpus (48.11%), Cx. quinquefasciatus (23.34%), and Limatus durhamii (0.07%). Biodiversity index was higher in forest galleries. Most adult Ae. albopictus were collected in forests close to pineapple fields (73/80), although only 2 larvae were detected in pineapple plants. Larval indices in adjacent houses (HI: 40.7%, CI: 26.9%) and distant houses (HI: 51.7%, CI: 29.6%) were similar (HI Z=0.56, p=0.58; CI Z=0.16, p=0.87). DENV-2 and DENV-3 were detected in 2/20 "pools" of Ae. albopictus heads and DENV-1 in 2/74 "pools" of larvae. Conclusion Forest galleries that are in proximity to pineapple plantations could be considered "ecological islands" that are suitable for refuge of Ae. albopictus. Presence of DENV in adults and larvae suggests an active role for Ae. albopictus in virus transmission within this ecosystem.

Determinación del intervalo post mortem mínimo (IPM) basado en un modelo de acumulación térmica con una cepa de Lucilia eximia (Diptera: Calliphoridae) de Costa Rica / Lucilia eximia (Diptera: Calliphoridae) as forensic indicator for the calculation of the post mortem interval in Costa Rica

RESUMEN Introducción: L. eximia es una especie de amplia distribución geográfica en Costa Rica, cuyas poblaciones son estables durante todo el año. Las características biológicas de ésta permiten concebirla como un potencial indicador forense para el cálculo del intervalo post mortem mínimo (IPM). Objetivo: Comparar el IPM calculado mediante un modelo de acumulación térmica con L. eximia (Diptera: Calliphoridae), con el IPM real en cadáveres de cerdos domésticos (Sus scrofa). Material y Métodos: Dos cadáveres de cerdo fueron expuestos en un bosque premontano húmedo tropical. A partir de dichos cadáveres se colectaron larvas de L. eximia a las 78, 144 y 192 horas posteriores al momento de muerte y se propició su desarrollo en condiciones controladas. Con los datos generados, se realizaron retroproyecciones térmicas para efectuar el cálculo del IPM. Resultados: L. eximia requirió en total 7 236,50 grados- hora acumulados (ADH) para culminar su desarrollo. Los IPM calculados mediante el modelo de acumulación térmica para los tres momentos de colecta fueron 112,56; 153,60 y 104,64 horas. Únicamente el valor intermedio no presentó diferencias estadísticamente significativas con el tiempo de muerte conocido (p>0.05). Conclusiones: El modelo de acumulación térmica en que se utilizó L. eximia brindó información precisa sobre el IPM sólo cuando se tomaron las muestras en el campo a las 144 horas, lo que perfila su utilidad para las primeras etapas de la descomposición cadavérica.

ABSTRACT Introduction: L. eximia is a species that shows a wide geographical distribution in Costa Rica, whose populations are stable throughout the year. The biological characteristics of L. eximia allow it to be considered as a potential forensic indicator for the calculation of the minimum post mortem interval (PMI). Objective: To compare the PMI calculated by a thermal accumulation model with L. eximia (Diptera: Calliphoridae), with the PMI in corpses of pigs (Sus scrofa). Methods: Two pig corpses were exposed in a tropical premontane moist forest. Larvae of L. eximia were collected from the pig carcasses at 78, 144 and 192 hours after the moment of death, and their development was promoted under controlled conditions. With the data generated, thermal back-projections were made to calculate the PMI. Results: L. eximia required a total of 7 236.50 accumulated degree hours (ADH) to complete its life cycle. The IPMs calculated by the thermal accumulation model were 112.56, 153.60, and 104.64 hours, respectively. Only the intermediate value did not present statistically significant differences with the known time of death (p>0.05). Conclusions: The thermal accumulation model using L. eximia as a forensic indicator provided accurate information about the PMI only when samples were collected at 144 hours, which indicates that this method may be accurate and useful during the first stages of cadaveric decomposition.

Resistencia de Aedes aegypti (diptera: culicidae) a insecticidas organofosforados y piretroides en la localidad de Orotina, Alajuela, Costa Rica / Resistance of Aedes aegypti (Diptera: Culicidae to organophosphate and pyrethroid insecticides in Orotina, Alajuela, Costa Rica

Objetivos: Determinar la resistencia de una cepa de Aedes. aegypti de Orotina a insecticidas organofosforados (temefós y malatión), y a piretroides (deltametrina, lambda cialotrina y cipermetrina). Métodos: La evaluación de la resistencia se efectuó mediante bioensayos larvarios. A partir de cada uno de los insecticidas se calculó la concentración letal 50% (CL50). También se calculó el factor de resistencia 50% (FR50) con respecto a la cepa Rockefeller, que sirvió como control susceptible. En casos de resistencia, la evaluación se repitió exponiendo previamente las larvas a butóxido de piperonilo (BP), S, S, S tributilfosforotritionato (DEF) y ácido etacrínico (AE) para establecer los mecanismos de detoxificación asociados con la resistencia. En cada caso se calculó un factor de sinergismo 50% (FS50). Resultados: La cepa Orotina mostró susceptibilidad a temefós, malatión, deltametrina y lambda cialotrina, pero mostró resistencia incipiente a cipermetrina (CL50= 0,01103 mg/L, FR50 = 5,32). Sólo el BP revertió la resistencia a este insecticida (FS50 =10,92), lo que representa un mecanismo de detoxificación asociado con el sistema citrocromo P450 monooxigenasa. Discusión: Aunque la cepa de Ae. aegyptide Orotina mostró resistencia a cipermetrina, existen otros insecticidas para los cuales fue susceptible, que brindan opciones a las autoridades de salud para su implementación en el control químico del vector. Conclusiones: El monitoreo de la resistencia es requerido para asegurar la efectividad de los insecticidas que se utilizan en el control químico.

Abstract Objectives: To determine the resistance to organophosphate (temephos and malathion) and pyrethroid (deltamethrin, lambda cyhalothrin, and cypermethrin) insecticides in a strain of Aedes aegypti from Orotina. Methods: The evaluation of the resistance was carried out by larval bioassays. Lethal concentration 50% (LC50) was calculated for each insecticide. A factor of resistance 50% (FR50) was also calculated with respect to the Rockefeller strain, which served as susceptible control. In cases of resistance, the evaluation was replicated by exposing the larvae to piperonyl butoxide (PB), S, S, S tributylphosphorotritionate (DEF), and ethacrynic acid (AE), in order to establish the detoxification mechanisms associated with the resistance. In these cases, a factor of synergism 50% (FS50) was also calculated. Results: The Orotina strain of Ae. aegyptiwas susceptible to temephos, malathion, deltamethrin and lambda cyhalothrin, but showed incipient resistance to cypermethrin (LC50 = 0.01103 mg/L, FR50 = 5.32). Only PB reversed the state of resistance (FS50 = 10.92), which suggests a detoxification mechanism associated with the citochrome P450 monooxygenase system. Discussion: Although the Ae. aegyptistrain from Orotina showed resistance to cypermethrin, it was susceptible to other insecticides, which can be used as alternative options for chemical control of the vector. Conclusions: Monitoring of resistance is required to ensure the effectiveness of insecticides used in chemical control.

Resistencia a insecticidas en cepas de Aedes aegypti (Diptera: Culicidae) de tres distritos de la Región Pacífico Central de Costa Rica / nsecticide resistance in Aedes aegypti (Diptera: Culicidae) strains from three districts of the Central Pacific Region of Costa Rica

Introducción: Aedes aegypti es vector de virus dengue, chikungunya y Zika en Costa Rica. Su alta incidencia y carencia de vacunas hacen del control vectorial, incluyendo el químico, la única alternativa para disminuir su transmisión. El uso reiterativo de insecticidas propicia su resistencia. Objetivo: Determinar la resistencia y mecanismos de detoxificación enzimática a temefós e insecticidas piretroides en cepas de Ae. aegypti de tres distritos de la Región Pacífico Central de Costa Rica. Métodos: La resistencia a temefós, deltametrina y cipermetrina fue determinada en tres cepas de Barranca, Jacó y Quepos mediante bioensayos en larvas. Para cada insecticida se calculó la concentración letal 50 por ciento (CL50) y un factor de resistencia 50 por ciento(FR50), empleando la cepa Rockefeller como control. Ante la ocurrencia de resistencia, se repitieron los bioensayos utilizando butóxido de piperonilo, S,S,S, tributilfosforotritioato y ácido etacrínico que inhiben monooxigenasas, esterasas y glutatión S transferasa, respectivamente. Resultados: Ninguna cepa mostró resistencia a temefós. Las cepas Barranca y Jacó fueron resistentes a deltametrina (FR50= 7,38; 28,23, respectivamente). La cepa Jacó mostró, adicionalmente, resistencia a cipermetrina (FR50= 7,70). La cepa Quepos no mostró resistencia a ningún piretroide. Solo la cepa Barranca mostró disminución de resistencia a deltametrina asociada al butóxido de piperonilo denotando vinculación con monooxigenasas (FR50: 10,10). Para los otros casos de resistencia, ninguno de los sinergistas disminuyó la resistencia. Conclusiones: Las larvas de Ae. aegypti de las localidades evaluadas no mostraron resistencia a temefós. Respecto a piretroides se evidenció la aparición de resistencia que posiblemente no es mediada por detoxificación enzimática(AU)

Introduction: Aedes aegypti is the vector of dengue, chikungunya, and Zika viruses in Costa Rica. The high incidence and the lack of vaccines make vector control, including chemical control, the only measure to prevent transmission. The repetitive use of insecticides may induce resistance. Objective: To determine resistance and enzymatic detoxifying mechanisms to temephos and pyrethroids insecticides in strains of Ae. aegypti from three districts of the Central Pacific Region of Costa Rica. Methods: Resistance to temephos, deltamethrin, and cypermethrin was determined in three strains of Barranca, Jacó, and Quepos by larval bioassays. In each test, the lethal concentration 50 percent (LC50) and a factor of resistance 50 percent (FR50) were calculated, using the Rockefeller strain as control. When resistance was observed, the bioassays were repeated using piperonyl butoxide, S,S,S, tributylphosphorotritioate, and ethacrynic acid, that inhibit monoxygenases, esterases, and glutathione S- transfererase, respectively. Results: None of the strains were resistant to temephos. Resistance to deltamethrin (FR50= 7.38 and FR50= 28.23, respectively) was determined in the strains from Barranca and Jacó, while resistance to cypermethrin was detected only in Jacó (FR50= 7.70). The Quepos strain was not resistant to any pyrethroid. Only the Barranca strain showed a decrease in the resistance to deltamethrin when piperonyl butoxide was used, linking the resistance to monooxygenase enzymes (FR50: 10.10). For the other cases, none of the synergists decreased the resistance. Conclusions: Larvae of Ae. aegypti from the localities evaluated were not resistant to temephos. With respect to pyrethroids, results show an emergence of resistance that may not be mediated by enzymatic detoxification(AU)

Nuevos registros de Aedes albopictus (Skuse) en cuatro localidades de Costa Rica / New records of Aedes albopictus (Skuse) in four locations of Costa Rica

Resumen Introducción Aedes albopictus (Skuse) es un vector de arbovirus ampliamente distribuido. En Costa Rica, la expansión geográfica de Ae. albopictus se ha incrementado en la última década, por lo que es importante actualizar el conocimiento sobre su distribución. Objetivo Informar sobre el hallazgo de Aedes albopictus en nuevas localidades de Costa Rica. Materiales y Métodos Se colectaron formas inmaduras de mosquitos con morfología sugestiva de Ae. albopictus en localidades de las provincias de Puntarenas (isla de Chira y Golfito), Guanacaste (Liberia), Alajuela (Upala), San José (Acosta) y Heredia (Sarapiquí). Los especímenes fueron fijados en etanol al 70%, aclarados en lactofenol e identificados con el uso de claves dicotómicas. Resultados Las especies identificadas fueron Ae. albopictus, Aedes aegypti, Haemagogus equinus y Haemagogus iridocolor-H. lucifer. Las de Ae. albopictus procedieron de los siguientes depósitos: recipiente plástico, tanque de agua, lona plástica, balde, llanta, canoa, piscina, maceta y bota de hule. Se reporta la presencia de Ae. albopictus en Liberia (Guanacaste), isla de Chira y Golfito (Puntarenas) y Upala (Alajuela). Conclusiones Se evidencia la expansión que ha experimentado Ae. albopictus en Costa Rica. Se enfatiza la necesidad de un diagnóstico microscópico certero, pues las larvas de Ae. albopictus pueden coexistir con otras especies que resultan difíciles de diferenciar, tales como Ae. aegypti y algunas especies de Haemagogus. Considerando que Ae. albopictus es un vector competente para virus dengue (DENV), chikungunya (CHIKV) y Zika (ZIKV), se recomienda investigar su papel en la transmisión de virus en estas zonas, así como el desplazamiento y/o coexistencia con especies como Ae. aegypti.

Abstract Introduction Aedes albopictus (Skuse) is a vector of arboviruses that is widely-distributed. In Costa Rica the geographical expansion of Ae. albopictus has increased in the past decade, which requires updating knowledge about its distribution. Objective To report the finding of Aedes albopictus in new localities of Costa Rica. Materials and Methods Immature stages of mosquitoes that were morphologically suggestive of Ae. albopictus were collected in localities of the provinces of Puntarenas (Chira island and Golfito), Guanacaste (Liberia), Alajuela (Upala), San José (Acosta) and Heredia (Sarapiquí). Specimens were fixed in 70 % ethanol, cleared in lactophenol, and identified using dichotomous keys. Results The species identified were: Ae. albopictus, Aedes aegypti, Haemagogus equinus, and Haemagogus iridocolor-H. Lucifer. The ones of Ae. albopictus were in the following container types: plastic container, water tank, plastic tarp, bucket, tire, roof gutter, swimming pool, flower pot and rubber boot. This is the first scientific report of Ae. albopictus in Liberia (Guanacaste), Chira island and Golfito (Puntarenas), and Upala (Alajuela). Conclusions There is evidence of the expansion of Ae. albopictus in Costa Rica. Emphasis is given as to the need for a precise microscopical diagnosis, since Ae. albopictus larvae may coexist with other species that may be difficult to differentiate, such as Ae. aegypti and some species of Haemagogus. Considering that Ae. albopictus is a competent vector for dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV) viruses, further investigation of its role in virus transmission is recommended in these areas, as well as displacement and/or coexistence with species like Ae. aegypti.

'Candidatus Rickettsia nicoyana': A novel Rickettsia species isolated from Ornithodoros knoxjonesi in Costa Rica.

Rickettsiae are intracellular bacteria commonly associated with hematophagous arthropods. Most of them have been described in hard ticks, but some have been found in soft ticks. Here we report the detection and isolation of a new Rickettsia from Ornithodoros knoxjonesi larvae collected from Balantiopteryx plicata (Emballonuridae) in Nicoya, Costa Rica. Two ticks were processed to detect Rickettsia spp. genes gltA, ompA, ompB, and htrA by PCR. Part of the macerate was also inoculated into Vero E6 and C6/36 cell lines, and cells were evaluated by Giménez stain, indirect immunofluorescence assay (IFA), and PCR. Both ticks were positive by PCR and rickettsial growth was successful in Vero E6 cells. Amplification and sequencing of near full length rrs, gltA, sca4 genes, and fragments of ompA and ompB showed that the Rickettsia sp. was different from described species. The highest homologies were with 'Candidatus Rickettsia wissemanii' and Rickettsia peacockii: 99.70% (1321/1325) with both sequences for rrs, 99.58% (1172/1177) and 99.76% (1246/1249) for gltA, 99.26% with both sequences (2948/2970 and 2957/2979) for sca4, 98.78% (485/491) and 98.39% (2069/2115) for ompA, and 98.58 (1453/1474) and 98.92% (1459/1475) for ompB; respectively. Bat blood, spleen, liver, and lung samples analyzed for Rickettsia detection were negative. Results demonstrate that the Rickettsia isolated from O. knoxjonesi is probably an undescribed species that belongs to the spotted fever group, for which 'Candidatus Rickettsia nicoyana' is proposed. Considering that B. plicata inhabits areas where contact with humans may occur and that human parasitism by Ornithodoros has been reported in the country, it will be important to continue with the characterization of this species and its pathogenic potential.

Detection of rickettsiae in fleas and ticks from areas of Costa Rica with history of spotted fever group rickettsioses.

Outbreaks of spotted fevers have been reported in Costa Rica since the 1950s, although vectors responsible for transmission to humans have not been directly identified. In this study, species of Rickettsia were detected in ectoparasites from Costa Rica, mostly from five study sites where cases of spotted fevers have been reported. Ticks and fleas were collected using drag cloths or directly from domestic and wild animals and pooled according to species, host, and location. Pools were analyzed initially by PCR to detect a fragment of Rickettsia spp. specific gltA gene, and those positive were confirmed by detection of htrA and/or ompA gene fragments. Partial sequences of the gltA gene were obtained, as well as at least one ompA and/or ompB partial sequence of each species. Rickettsia spp. were confirmed in 119 of 497 (23.9%) pools of ticks and fleas analyzed. Rickettsia rickettsii was identified in one nymph of Amblyomma mixtum and one nymph of Amblyomma varium. Other rickettsiae present were 'Candidatus Rickettsia amblyommii' in A. mixtum, Amblyomma ovale, Dermacentor nitens, and Rhipicephalus sanguineus s. l.; Rickettsia bellii in Amblyomma sabanerae; Rickettsia felis in Ctenocephalides felis; and Rickettsia sp. similar to 'Candidatus R. asemboensis' in C. felis, Pulex simulans, A. ovale, and Rhipicephalus microplus. Results show the presence of rickettsiae in vectors that may be responsible for transmission to humans in Costa Rica, and evidence suggests exposure to rickettsial organisms in the human environment may be common. This is the first study to report R. rickettsii in A. varium and in A. mixtum in Costa Rica.

Global genetic diversity of Aedes aegypti.

Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.

Evaluación de la resistencia a insecticidas en cepas de Aedes aegypti (Diptera: Culicidae) de la Región Caribe de Costa Rica / Evaluation of insecticide resistance in strains of Aedes aegypti (Diptera: Culicidae) from the Caribbean region of Costa Rica

Introducción: el dengue y chikungunya son virosis antroponóticas transmitidas por Aedes aegypti que afectan extensas áreas del continente americano incluyendo Costa Rica. La reciente introducción del virus Zika representa un nuevo reto para los sistemas de salud. Dada la ausencia de tratamiento antiviral y vacunas, el control del vector Ae. aegypti, representa la única alternativa para minimizar el impacto de estas virosis. En Costa Rica, el control químico del vector se hace mediante la aplicación de piretroides (cipermetrina y deltametrina) y del organofosforado temefós; de ahí la importancia de detectar la aparición de resistencia a estos insecticidas. Objetivo: determinar el nivel de resistencia a temefós, cipermetrina y deltametrina en tres cepas de Ae. aegypti de la Región Caribe de Costa Rica, así como los mecanismos de detoxificación enzimática correspondientes. Métodos: la resistencia a temefós, cipermetrina y deltametrina se evaluó mediante bioensayos larvarios. Grupos de 20 larvas se expusieron por 24 h a 5 concentraciones de insecticidas que generaron una mortalidad entre el 2 y el 100 por ciento. Cada concentración se evaluó mediante cinco réplicas y se calculó la concentración que causa el 50 por ciento de letalidad (CL50). Como control susceptible se empleó la cepa Rockefeller. Con cada cepa se calculó un factor de resistencia 50 por ciento (FR50) para cada insecticida. Cuando se observó resistencia, se repitieron los bioensayos mediante exposición previa de las larvas a butóxido de piperonilo (PB) y S,S,S, tributilfosforotritioato (DEF) para evaluar el mecanismo detoxificante relacionado. Resultados: ninguna de las cepas evaluadas fue resistente al temefós. En las cepas Guápiles y Limón se determinó una resistencia incipiente a cipermetrina (CL50= 0,01022, FR50= 7,35 y CL 50= 0,01016, FR50= 7,30, respectivamente), mientras que en la cepa Siquirres se detectó resistencia a deltametrina (CL50= 0,01973 mg/L, FR5= 12,64). En los casos referidos hubo una disminución de la resistencia cuando se dio el pretratamiento con PB, lo que indica una detoxificación mediada por el sistema Cit P450 monooxigenasa. Conclusiones: los resultados en el presente estudio demuestran que el temefós sigue siendo efectivo para el control larvario de Ae. aegypti en las principales localidades de la región Caribe de Costa Rica. Con respecto a los piretroides se alerta ante la aparición de resistencia, lo que conlleva la necesidad de optimizar los procesos de monitoreo y la implementación de otras alternativas de control químico(AU)

Introduction: dengue and chikungunya are anthroponotic virus infections transmitted by Aedes aegypti mosquitoes. These conditions affect large areas of the American continent, including Costa Rica. The recent introduction of Zika virus infection is a new challenge for health systems. Given the absence of antiviral treatment and vaccines, Aedes aegypti control is the only alternative to minimize the impact of these viral diseases. In Costa Rica chemical control of the vector is based on the use of pyrethroids (cypermethrin and deltamethrin) and the organophosphate larvicide temephos, hence the importance of detecting the emergence of resistance to these insecticides. Objective: determine the level of resistance to temephos, cypermethrin and deltamethrin in three Aedes aegypti strains from the Caribbean region of Costa Rica, as well as the corresponding enzymatic detoxification mechanisms. Methods: resistance to temephos, cypermethrin and deltamethrin was evaluated with larval bioassays. Groups of 20 larvae were exposed to 5 insecticide concentrations for 24 h. Mortality ranged between 2 and 100 percent. Each concentration was evaluated by means of five replications, and estimation was performed of the concentration causing 50 percent lethality (CL50). The Rockefeller strain was used as susceptible control. Each strain underwent estimation of a 50 percent resistance factor (RF50) for each insecticide. Whenever resistance was observed, the bioaasays were repeated with prior exposure of the larvae to piperonyl butoxide (PBO) and S.S.S. phosphotrithiate tributyl (DEF) to evaluate the corresponding detoxification mechanism. Results: none of the strains evaluated was resistant to temephos. Incipient resistance to cypermethrin was detected in strains Guápiles and Limón (CL50= 0.01022, RF50= 7.35 and CL 50= 0.01016, RF50= 7.30, respectively), whereas resistance to deltamethrin was detected in the Siquirres strain (CL50= 0.01973 mg/L, RF50= 12.64). In the above-mentioned cases resistance decreased when pre-treatment with PBO was provided, indicating the presence of detoxification mediated by the Cyt P450 monooxygenase system. Conclusions: results show that temephos continues to be effective for larval control of Aedes aegypti in the main areas of the Caribbean region of Costa Rica. A warning is hereby given about the emergence of pyrethroid resistance, leading to the need to optimize monitoring processes and the implementation of other chemical control alternatives(AU)

Exposure of dogs to spotted fever group rickettsiae in urban sites associated with human rickettsioses in Costa Rica.

The zoonotic transmission cycles of Rickettsia rickettsii and other spotted fever group (SFG) rickettsiae in Latin America have usually been associated with rural or sylvatic environments, although domestic dogs can be implicated in more populated settings. In this study, exposure of dogs to SFG rickettsiae in the Greater Metropolitan Area of Costa Rica was investigated. Dogs from sites associated with human cases and from dog shelters were evaluated by indirect immunofluorescence assay (IFA) using antigen of SFG rickettsiae. Rickettsia spp. were detected in ectoparasites by polymerase chain reaction (PCR). A total 18.5% (31/168) of dogs associated with human cases and 6.8% (11/161) of dogs in shelters had IgG end titers≥64 to Rickettsia spp. The odds of being seropositive were greater in dogs from areas associated with human cases when compared to shelters (OR: 3.2; 95% C.I: 1.5-5.6). Rhipicephalus sanguineus sensu lato (s. l.) was present in all sites associated with human cases. Rickettsia felis URRWXCal2 and R. felis-like RF2125 were detected in Ctenocephalides felis, and Rickettsia sp. IbR/CRC in Ixodes boliviensis. Results demonstrate that dogs from the main urban center of Costa Rica have been exposed to SFG rickettsiae, especially in areas with known human infection. Both human and animal health sectors must be aware of possible rickettsial diseases in urban areas, where dogs may also serve as sentinels for human infection.

Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky Mountain spotted fever in areas where both species circulate.

Chikungunya: un virus que nos acecha / Chikungunya: a threatening virus

El virus chikungunya representa una amenaza para Costa Rica. Este arbovirus ha sido introducido al continente americano desde finales de 2013. Debido a sus características epidemiológicas y virológicas, y a la presencia de sus vectores en el país, este virus puede llegar a convertirse en la nueva enfermedad endémica de Costa Rica. Aunque el chikungunya tiene una baja tasa de mortalidad, su alta tasa de ataque podría colapsar el sistema de salud nacional durante una epidemia. En esta revisión se resume aspectos clínicos, virológicos, epidemiológicos y entomológicos relacionados con esta virosis, para identificar, diagnosticar y diferenciar posibles casos de fiebre por chikungunya en el país. Además, se enfatiza en el control epidemiológico y de vectores, para prevenir epidemias de esta enfermedad en Costa Rica.

Chikungunya virus represents a threat to Costa Rica. This arbovirus was introduced to the American continent during the last trimester of 2013. Due to its epidemiological and virological characteristics, as well as to the presence of its vectors in the territory, chikungunya could become the next novel endemic disease in Costa Rica. Although chikungunya has a low mortality rate, its high rate of attack could cause a collapse of the national health system during an epidemic. In this review we summarize the clinical, virological, epidemiological and entomological characteristics associated to chikungunya virus for a proper identification, diagnosis and differentiation of chikungunya fever cases in the country. Furthermore, we emphasize the importance of the epidemiological and vector control in order to prevent epidemics of this disease in Costa Rica.

Perfil de resistencia a insecticidas en una cepa de Aedes aegypti (Linnaeus) de la región Caribe de Costa Rica / Insecticidal resistance profiles of an Aedes aegypti (Linnaeus) strain from the Caribbean Region of Costa Rica

Introducción: el dengue constituye la principal enfermedad de transmisión vectorial en Costa Rica. El control del vector Aedes aegypti consiste en la aplicación de piretrinas y temefós, por lo cual es importante monitorear la aparición de resistencia a estos insecticidas. Materiales y métodos: se efectuaron bioensayos con larvas de Ae. aegypti procedentes del cantón de Guácimo en la Región Caribe de Costa Rica. Grupos de 20 larvas fueron expuestos por 24 horas a concentraciones de insecticidas que provocaran una mortalidad entre el 2 y el 100 por ciento. Las pruebas fueron efectuadas por quintuplicado y se calculó la concentración letal 50 por ciento (CL50). Como control susceptible se empleó la cepa Rockefeller. Un radio de resistencia 50 por ciento (RR50) fue calculado para cada insecticida. En caso de resistencia se repitieron los ensayos exponiendo las larvas a butóxido de piperonilo (PB) y S, S, S, tributilfosforotritioato (DEF) para perfilar el mecanismo enzimático vinculado con dicha resistencia. Resultados: no se observó resistencia a temefós y deltametrina, pero sí se encontró resistencia incipiente a la cipermetrina (CL50 = 0,00845 mg/L, rango: 0,00664-0,01038, RR50 = 6,07). El análisis con sinergistas determinó un radio de singergismo (RS) de 19,2 para el PB y de 0,9 para DEF. Discusión: los resultados demuestran que existe un proceso de desarrollo de resistencia a la cipermetrina en los mosquitos Ae. aegypti en esta localidad, el cual está relacionada con la actividad citocromo P450 monooxigenasa. Esto alerta a las autoridades para sustituir dicho insecticida y así asegurar el adecuado control del vector sin la generación de resistencia(AU)

Introduction: dengue is the main vector-borne disease in Costa Rica. The control of the vector Aedes aegypti covers the application of pyrethrins and temephos. For this reason, it is important to monitor the development of resistance to these insecticides. Material and Methods: bioassays were performed using Ae .aegypti larvae from the county of Guacimo in the Caribbean region of Costa Rica. Twenty-larvae groups were exposed to insecticidadl concentrations for 24 hours, which would generate 2 to 100 percent mortality. The tests were performed five times, and a 50 percent lethal concentration (LC50) was calculated. The Rockefeller strain was used as susceptibility control. A 50 percent resistance ratio (RR50) was calculated for each insecticide. When resistance occurred, tests were repeated by exposing the larvae to piperonyl butoxide (PB) and S, S, S, tributylphosphorotrithioate (DEF) in order to determine the enzymatic mechanism associated with this resistance. Results: no resistance to temephos or deltamethrin was observed, but emerging resistance to cypermethrin was detected (LC50 = 0.00845 mg/L, range from 0.00664 to 0.01038, RR50 = 6.07). The synergistic analysis determined a synergism ratio (SR) of 19.2 for PB and 0.9 for DEF. Conclusions: these results show that there is a process of developing resistance to cypermethrin in Ae. aegypti mosquitoes of this county, which is associated with cytochrome P450 monooxygenase activity. This alerts authorities to the need of replacing this insecticide and ensure the appropriate vector control without generating resistance(AU)

[Nosocomial myiasis in Latin America and the Caribbean: an overlooked reality?]. / Miasis nosocomiales en América Latina y el Caribe: ¿una realidad ignorada?

Nosocomial myiasis is an infestation by fly larvae that occurs while a patient is hospitalized. To analyze the available information on nosocomial myiasis in Latin America and the Caribbean, a search was done for cases published in the last 52 years. Nine clinical cases were found for Brazil, Costa Rica, French Guiana, Honduras, and Jamaica. Two other publications mention 139 cases in El Salvador and some 32 in Colombia, respectively. The patients and environments described presented conditions that predispose to this type of infestation. Compulsory notification is not usually required for nosocomial myiasis in Latin America and the Caribbean, meaning that there is probably considerable underreporting. Awareness needs to be raised and registry improved of myiasis in the region to aid in adoption of better prevention measures, which will benefit patient care during hospitalization.

Miasis nosocomiales en América Latina y el Caribe: ¿una realidad ignorada? / Nosocomial myiasis in Latin America and the Caribbean: an overlooked reality?

Las miasis nosocomiales son infestaciones por larvas de mosca que se producen después de la hospitalización del paciente. Para analizar la información disponible sobre miasis nosocomiales en América Latina y el Caribe, se realizó una búsqueda de casos publicados en los últimos 52 años. Se encontraron nueve casos clínicos en Brasil, Costa Rica, Guayana Francesa, Honduras y Jamaica. También existen dos publicaciones con datos agregados que mencionan 139 casos en El Salvador y alrededor de 32 en Colombia. Los pacientes y el entorno descritos en los casos presentaron condiciones que predisponen a este tipo de infestaciones. Las miasis nosocomiales en América Latina y el Caribe no suelen ser de declaración obligatoria, por lo que es probable que exista un importante subregistro. Es necesario crear conciencia y mejorar el registro de estas miasis en la región para tomar las medidas más adecuadas de prevención, que beneficien el cuidado del paciente durante su hospitalización.

Nosocomial myiasis is an infestation by fly larvae that occurs while a patient is hospitalized. To analyze the available information on nosocomial m yiasis in Latin America and the Caribbean, a search was done for cases published in the last 52 years. Nine clinical cases were found for Brazil, Costa Rica, French Guiana, Honduras, and Jamaica. Two other publications mention 139 cases in El Salvador and some 32 in Colombia, respectively. The patients and environments described presented conditions that predispose to this type of infestation. Compulsory notification is not usually required for nosocomial myiasis in Latin America and the Caribbean, meaning that there is probably considerable underreporting. Awareness needs to be raised and registry improved of myiasis in the region to aid in adoption of better prevention measures, which will benefit patient care during hospitalization.