Peridomestic Areas Research Articles

COYOTES (CANIS LATRANS) IN ARIZONA, USA, EXHIBIT IMMUNE AND GENETIC EVIDENCE OF RICKETTSIAL INFECTIONS

Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii, was recognized as endemic in Arizona, US after a 2002 outbreak and has since been a public health concern. The brown dog tick (Rhipicephalus sanguineus sensu lato) is the principal vector of this pathogen in Arizona. Domesticated dogs (Canis lupus familiaris) are the tick's main host, so free-roaming dogs in peridomestic areas have been named the primary risk factor for human cases of RMSF. However, the sudden emergence and long-distance dispersal of the pathogen have not been adequately explained, and one possible mechanism could include wildlife. Coyotes (Canis latrans) are wide ranging in Arizona and closely related to dogs, so it is possible that brown dog ticks parasitize coyotes and infect them. Although R. rickettsii is the most severe spotted fever group (SFG) rickettsial pathogen in humans, others occur in Arizona, and antibodies raised against them are cross-reactive, so we more-broadly hypothesized that coyotes in Arizona are exposed to SFG rickettsiae. We collected coyote tissues in spring 2016 and 2017. We tested sera for antibodies to R. rickettsii and found 9% (8/94) of samples were antibody-positive with titers of ≥256. Subsequent quantitative PCR analyses of skin showed evidence for Rickettsia spp. in 2.9% (4/138) of samples. These data suggest that coyotes have a role in the maintenance of SFG rickettsiae in Arizona. Further investigation is warranted to reveal which specific pathogen-vector complexes act on coyotes in the region and whether they represent a risk to human health.

Post Flood Dengue Vector Surveillance-An Experience from Ernakulum District of Kerala, India in 2018

Introduction: Floods increase the transmission of water and vector borne diseases. In August 2018, severe floods affected the south Indian state Kerala. Present study was conducted in Ernakulam district of Kerala. Objectives: (i) To determine the major breeding sources for mosquitoes in the peri-domestic area (ii) to identify the species of mosquitoes and (iii) to analyse the vector (larval) indices. Material and Methods: A cross-sectional descriptive study was conducted in Ernakulam district of Kerala by using a mix method. Data was collected from 15th to 30th September, 2018 by House to House survey, Review of IDSP records and interview of key health officials of the district. Larval survey was done in 525 houses selected from 11 purposively selected areas. Data was entered and objective wise analysis was done by using Microsoft Excel and data was presented in number and percentages. Result: Ernakulam district is endemic for dengue fever. Out of total 1580 containers inspected maximum were of plastic (35.7%), followed by metals (21.9%) and plastic drums (9.9%). House Index ranged from 2 - 18 percent. Container Index ranged from 0.6 - 6.3 percent. Breatu Index ranged from 1.8 - 24.8 percent. Out of total 51 mosquitoes, 33 (64.7%) were Aedes Albopictus, 4 (7.8%) were Aedes Pseudotaeniatus, 5 (9.8%) were Armigeres Subalbatus and 9 (17.6%) were Culex Quinquefasciatus. Conclusion: High level of all the vector indices and plenty of empty containers is responsible for endemicity of dengue and it can give rise to outbreak at any point of time.

Detection of enzootic circulation of a new strain of West Nile virus lineage 1 in sentinel chickens in the north of Tunisia

Tunisia has experienced various West Nile disease outbreaks. Notwithstanding the serological and molecular confirmations in humans, horses and birds, the human surveillance system can still be improved. Three sentinel chicken flocks were placed in different Tunisian endemic regions and followed up from September 2016 to January 2017. A total of 422 sera from Sejnene (north of Tunisia), 392 from Moknine (east coast of Tunisia) and 386 from Tozeur (south of Tunisia) were tested for West Nile-specific antibodies and viral RNA. The WNV elisa positive rate in sentinel chickens in Sejnene was 10.7% (95% CI: 5.08-21.52). No positive samples were detected in Moknine. In Tozeur, the overall serological elisa positive rate during the study period was 9.8% (95% CI:4.35-21.03). West Nile virus nucleic acid was detected in two chickens in Sejnene.Phylogenetic analysis of one of the detected partial NS3 gene sequences showed that recent Tunisian WNV strain belong to WNV lineage 1 and is closely related to Italian strains detected in mosquitoes in 2016 and in a sparrow hawk in 2017. This report showed the circulation, first molecular detection and sequencing of WNV lineage 1 in chickens in the north of Tunisia and highlights the use of poultry as a surveillance tool to detect WNV transmission in a peri-domestic area.

A 19 Year Analysis of Small Mammals Associated with Human Hantavirus Cases in Chile.

Small mammals present in areas where hantavirus cardiopulmonary syndrome (HCPS) cases had occurred in central and southern Chile were captured and analyzed to evaluate the abundance of rodents and seroprevalence rates of antibodies to Andes orthohantavirus (ANDV). Sampling areas ranged from the Coquimbo to Aysén regions (30–45° S approx.) regions. Ninety-two sites in peridomestic and countryside areas were evaluated in 19 years of sampling. An antibody against ANDV was detected by strip immunoassay in 58 of 1847 specimens captured using Sherman traps. Of the eleven species of rodents sampled, Abrothrix olivacea, Oligoryzomys longicaudatus and Abrothrix hirta were the most frequently trapped. O. longicaudatus had the highest seropositivity rate, and by logistic regression analysis, O. longicaudatus of at least 60 g had 80% or higher probability to be seropositive. Sex, age and wounds were significantly related to seropositivity only for O. longicaudatus. Across administrative regions, the highest seropositivity was found in the El Maule region (34.8–36.2° S), and the highest number of HCPS cases was registered in the Aysén region. Our results highlight the importance of long term and geographically extended studies, particularly for highly fluctuating pathogens and their reservoirs, to understand the implications of the dynamics and transmission of zoonotic diseases in human populations.

Higher risk of malaria transmission outdoors than indoors by Nyssorhynchus darlingi in riverine communities in the Peruvian Amazon

BackgroundMalaria remains an important public health problem in Peru where incidence has been increasing since 2011. Of over 55,000 cases reported in 2017, Plasmodium vivax was the predominant species (76%), with P. falciparum responsible for the remaining 24%. Nyssorhynchus darlingi (previously Anopheles darlingi) is the main vector in Amazonian Peru, where hyperendemic Plasmodium transmission pockets have been found. Mazán district has pronounced spatial heterogeneity of P. vivax malaria. However, little is known about behavior, ecology or seasonal dynamics of Ny. darlingi in Mazán. This study aimed to gather baseline information about bionomics of malaria vectors and transmission risk factors in a hyperendemic malaria area of Amazonian Peru.MethodsTo assess vector biology metrics, five surveys (two in the dry and three in the rainy season), including collection of sociodemographic information, were conducted in four communities in 2016–2017 on the Napo (Urco Miraño, URC; Salvador, SAL) and Mazán Rivers (Visto Bueno, VIB; Libertad, LIB). Human-biting rate (HBR), entomological inoculation rate (EIR) and human blood index (HBI) were measured to test the hypothesis of differences in entomological indices of Ny. darlingi between watersheds. A generalized linear mixed effect model (GLMM) was constructed to model the relationship between household risk factors and the EIR.ResultsNyssorhynchus darlingi comprised 95% of 7117 Anophelinae collected and its abundance was significantly higher along the Mazán River. The highest EIRs (3.03–4.54) were detected in March and June in URC, LIB and VIB, and significantly more Ny. darlingi were infected outdoors than indoors. Multivariate analysis indicated that the EIR was >12 times higher in URC compared with SAL. The HBI ranged from 0.42–0.75; humans were the most common blood source, followed by Galliformes and cows. There were dramatic differences in peak biting time and malaria incidence with similar bednet coverage in the villages.ConclusionsNyssorhynchus darlingi is the predominant contributor to malaria transmission in the Mazán District, Peru. Malaria risk in these villages is higher in the peridomestic area, with pronounced heterogeneities between and within villages on the Mazán and the Napo Rivers. Spatiotemporal identification and quantification of the prevailing malaria transmission would provide new evidence to orient specific control measures for vulnerable or at high risk populations.

Distribution of triatomine (Hemiptera: Reduviidae) vectors of Chagas disease in the state of Hidalgo, Mexico.

Chagas disease represents a significant public health problem in Mexico. In the state of Hidalgo, studies on the presence of triatomines are scarce and restricted to a few locations. To determine the risk of transmission in the state of Hidalgo and stratify the vector potential, the distribution of Triatominae was surveyed from 2015 to 2016 in collaboration with primary health care services and local communities. A total of 570 specimens was collected in 278 houses in 25 municipalities. The species of Triatominae detected were T. dimidiata with 391 samples, T. mexicana with 159 samples, T. gerstaeckeri with 17 samples, and T. barberi with three samples. The samples were collected in domestic and peridomestic areas. The general index of natural infection was 9.8%. Indices of colonization and crowding were determined for species and municipality and results were variable.

Temporal Variation in Species Abundance and Richness of Culicoides (Diptera: Ceratopogonidae) in a Tropical Equatorial Area.

The aim of this study was to investigate whether temperature, rainfall, and humidity influence the annual distribution of Culicoides Latreille 1809, species abundance and richness in rural areas on São Luís Island in the state of Maranhão, Brazil. Biting midges were collected in housing for domestic animals in the peridomestic areas of 10 homes. A CDC light trap was installed in each peridomestic area from 6:00 p.m. to 6:00 a.m. once a month for 12 mo. In total, 23,633 individuals belonging to 26 Culicoides species were captured. The most abundant species were Culicoides diabolicus Hoffman, 1925 (27.43%), C. ignacioi Forattini, 1957 (25.9%), C. flavivenulus Costa Lima, 1937 (15.53%), C. insignis Lutz, 1913 (10.66%), C. filariferus Hoffman, 1939 (6.21%), C. boliviensis Spinelli & Wirth, 1984 (6.07%), C. foxi Ortíz, 1950 (2.83%), and C. leopoldoi Ortíz, 1951 (2.54%). Species richness and abundance were greater during the rainy season (24 species; 88% of the individuals) than during the dry season (18 species; 12% of individuals). However, persistent rain on the days the midges were collected or in the preceding 24 h adversely affected abundance. Mean monthly maximum temperature and rainfall on the day of the collection adversely affected Culicoides abundance and richness.

Factors associated with the presence of triatomines in rural areas of south Argentine Chaco.

The domestic and peridomestic presence of Triatoma infestans depends on several factors, such as human behavior, vector behavior, ecology, and the environment. This work was conducted in 139 domiciliary units, where triatomines were captured and risk factors in domiciles and peridomicilies were recorded. Household dwellers were interviewed to obtain information about practices regarding this disease and entomological indicators were calculated. Infestation indices were 59.7% for house compounds, 4.3% for domestic areas and 58.3% for the peridomestic areas. Intradomicile infestation was significantly associated with housing characteristics. The presence of chicken coops in peridomicilies was associated with an increased risk of infestation. Of the respondents, 80% did not recognize the importance of the peridomiciliary structures for triatomine control and had infested peridomicilies. The results show the importance of peridomiciles as refuge sites for Triatominae bugs; however, household dwellers do not perceive peridomiciles as areas that favor the presence of vectors. Actions for raising awareness about factors that favor the presence of triatomines are needed to improve the conditions of peridomiciliary environments.

Mites and Lice of Peri-Domestic Rodents Captured at a Mayan Community of Yucatán State, México

The main ectoparasites of small rodents at a Mayan community of Yucatan State, southeastern Mexico were determined. Rodents were trapped in peridomestic areas of 20 houses from March to September 2016. Ectoparasites were removed from the rodents and morphologically identified. Total rodents infested were 22.9% (53/231). Prevalence of ectoparasites by rodent species was 65% (13/20) on Sigmodon toltecus Saussure, 50% (4/8) on Peromyscus yucatanicus J.A. Allen & Chapman, 37.5% (3/8) on Heteromys gaumeri J.A. Allen & Chapman, 25% (30/120) on Rattus rattus L., and 4% (3/75) on Mus musculus L. In total, 250 ectoparasites were collected. Mites were identified as Androlaelaps fahrenholzi (Berlese) (n = 115), Echinolaelaps echidninus (Berlese) (n = 89), and Steptolaelaps heteromys Furman (n = 22), and lice were identified as Polyplax spinulosa (Burmeister) (n = 24). Results suggested association among particular ectoparasite and rodent species, i.e., P. spinulosa and E. echidninus with R. rattus. Likewise, S. heteromys was significantly associated with H. gaumeri, and A. fahrenholzi with S. toltecus. The presence of ectoparasites such as E. echidninus and P. spinulosa on peridomestic rodents indicated risk of pathogen transmission to humans in the study area; therefore, focusing on surveillance and control of rodents in household environments is imperative.

Ongoing quiescence in the Borborema Plateau Plague focus (Paraiba, Brazil).

Plague is a zoonosis caused by Yersinia pestis, whose cycle is based on a reservoir system composed of mammals and their fleas. Its transmission cycle presents long enzootic periods with undetected cases, sometimes misleading that the cycle is extinct. While surveillance activities in Brazil are being carried out only in some focal areas, the serologic results confirm the persistence of Y. pestis in all monitored areas. We studied the small mammal assembly and Y. pestis presencein the Borborema Plateau Focus within the state of Paraíba, which staged the last Brazilian plague outbreak (1986-1987), through aninventory and Y. pestis detection survey of small mammals in peridomestic and sylvatic areas from two municipalities in the state of Paraíba.The field sampling captured 45 specimens (27 marsupials, 18 rodents), of 10 species. Only two species (one marsupial, one rodent) were captured in both peridomestic and sylvatic ecotopes. The sylvatic ecotope had higher richness and abundance. No evidence of circulation of the pathogen was detected, however, this result does not discard the necessity of continuous epidemiological surveillance due to the risk of rekindling the foci after long dormant periods, especially given the current epidemiological transition occurring on a Global scale.

The resilience of Triatoma dimidiata: An analysis of reinfestation in the Nicaraguan Chagas disease vector control program (2010-2016).

BackgroundThe control of Triatoma dimidiata, a major vector of Chagas disease, was believed to eliminate Trypanosoma cruzi transmission in Central America. This vector was known for its ability to repeatedly reinfest human dwellings even after initial insecticide spraying. Current vector control programs assume that community-based surveillance can maintain low levels of infestation over many years, despite a lack of evidence in the literature to corroborate this assumption. This study aims to evaluate long-term reinfestation risk in the Nicaraguan vector control program from 2010 to 2016.MethodsWe collected data from a cohort of 395 houses in Pueblo Nuevo, Nicaragua. Primary data were collected through a field survey to assess post-intervention levels of T. dimidiata house infestation in 2016, two years after the large-scale insecticide spraying. We obtained secondary data from the records about past infestation levels and control activities between 2010 and 2015. Multilevel mixed-effects logistic regression analyses were used to identify factors associated with post-intervention house infestation.ResultsThe control program effectively reduced the infestation level from 2010 to 2014. Community-based surveillance was introduced in 2013; however, post-intervention infestation in 2016 had nearly reached pre-intervention levels in rural villages. Post-intervention house infestation was positively associated with poor wall construction, roofing tiles piled in the peri-domestic areas or the presence of dogs. Interestingly, the odds of post-intervention house infestation were one-fifth less when villagers sprayed their own houses regularly. Past infestation levels and the intensity of government-led insecticide spraying did not explain post-intervention house infestation.ConclusionsThe vector control program failed to offer sustained reductions in T. dimidiata house infestation. This experience would suggest that community-based surveillance is an insufficient approach to suppressing T. dimidiata house infestation over many years. This study provides evidence to suggest that control policies for T. dimidiata should be reconsidered throughout Central America.

Silent Orthohantavirus Circulation Among Humans and Small Mammals from Central Minas Gerais, Brazil.

New World orthohantaviruses are emerging RNA viruses that cause hantavirus cardiopulmonary syndrome (HCPS). These viruses are a burden to public health around the world with a lethality rate of around 60%. In South America, rodents of Sigmodontinae subfamily are the main reservoirs of orthohantaviruses. We described a serosurvey for orthohantaviruses circulation in an apparently healthy human population and small mammals from rural areas in Central Minas Gerais State, Brazil. A total of 240 individuals and 50 small mammals (26 rodents belonging to 10 different species and 24 marsupials from 4 different species) were sampled during 2012-2013. The seroprevalence rates of IgG/IgM antibodies in humans were 7.1 and 1.6%, respectively. Only one rodent, an Oligoryzomys nigripes captured in peridomestic area, tested positive for IgG antibodies and viral RNA. Our findings suggest a silent circulation of orthohantaviruses in a region of intensive agriculture production. The detection of seropositive humans in an area with a lack of previous HCPS reports highlights potential oligosymptomatic cases and the need for surveillance strategies that could reduce the risk of future outbreaks.

Prevalence, Abundance and Intensity of Eggs and Oocysts of Gastrointestinal Parasites in the Opossum Didelphis Virginiana Kerr, 1792 in Yucatan, Mexico.

SummaryVirginia opossum, Didelphis virginiana, is a synanthropic mammal associated with peridomestic areas of Yucatán, However, little is known about the gastrointestinal parasite infections of this species. The infection prevalence, mean abundance and mean intensity of eggs and oocysts of gastrointestinal parasites, in opossums captured in the peridomestic areas were estimated in six rural localities of Yucatán, Mexico. Eighty-four faecal samples were processed by flotation technique. McMaster test was used to estimate the number of helminth eggs and protozoa oocysts per gram of feces. Seven genera of gastrointestinal parasites were identified, and then infection prevalence was estimated as follows: Protozoa Eimeria sp. (51.9 %) and Sarcocystis sp. (1 %); nematodes Ancylostoma sp. (80.56 %), Cruzia sp. (62.04 %), Trichuris sp. (60.19 %), Capillaria sp. (29.63 %), Turgida sp. (23.15 %), Toxocara sp. (11.11 %), and Ascaris sp. (1.85 %); and one acanthocephalan: Oligacanthorhynchus sp. (14.81 %). This is the first study on the diversity of gastrointestinal parasites in Virginia opossums, and first evidence about the potential role of opossums in the transmission of zoonotic gastrointestinal parasites in peridomestic areas of Yucatán, Mexico.

Trypanosoma cruzi load in synanthropic rodents from rural areas in Chile

BackgroundTrypanosoma cruzi is the agent of Chagas disease, a major public health problem in Latin America. Many wild and domestic animals are naturally infected with T. cruzi; rodents are one of the groups which have been consistently detected infected in different countries. The aim of this work was to characterize blood T. cruzi load in naturally infected rodents from a Chagas disease endemic region in Chile.MethodsBaited traps were set in domestic and peridomestic areas of rural dwellings. The rodents were anesthetized and blood sampled; DNA was extracted and the parasite load was quantified by T. cruzi satellite DNA real-time PCR assays.ResultsSeventy-one rodents of four species, Rattus rattus, Mus musculus, Phyllotis darwini and Octodon degus, were captured; R. rattus was the most abundant species. Fifty-nine samples (83.1%) were T. cruzi-positive and the median value of the parasite load was 2.99 parasite equivalents (par-eq)/ml. The comparison of frequency of infection or parasite load by species showed no differences. However, one R. rattus presented very elevated parasitemia (1644 par-eq/ml).ConclusionsThe overall levels of parasitemia were similar to those found in humans in Chile. The high infection levels in exotic and endemic rodents very near to rural settlements increases their relevance as T. cruzi hosts.

Should I stay or should I go? Movement of adult Triatoma sordida within the peridomestic area of a typical Brazilian Cerrado rural household

BackgroundChagas disease, or American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi, which is primarily transmitted to humans by hematophagous insects of the subfamily Triatominae. Although knowledge on triatomine movement capabilities at the micro-geographical scale is of fundamental importance concerning the development of effective vector control strategies, it remains a poorly understood subject. Furthermore, survival rates and size estimates of natural populations are important topics to consider when evaluating transmission intensity.ResultsThe movement of adult Triatoma sordida within the peridomestic area of a rural Brazilian household was evaluated via mark-release-recapture assays. A total of 210 insects had their pronota marked with fluorescent dyes and were released at different distances from the chicken coop (two, five, ten and 20 m), and from the horse corral (27, 32, 35, 46 and 56 m). Recaptures occurred in three consecutive 15-day intervals. Specimens were successfully recaptured at all distances up to 32 m. Bayesian models were used to estimate recapture probability, survival rates (males vs females) and population size. Although recapture probability was inversely proportional to distance for both sexes, females were more affected by increased distance. On the other hand, no significant difference was detected in the survival rates between males and females in a 15-day period. Fisher-Ford and Bayesian models gave more accurate population size estimates than Lincoln method.ConclusionsTriatoma sordida adults were able to cover a distance of 32 m in 45 days. Recapture data modelling reveals that male dispersal was more effective suggesting that T. sordida males are more likely to contribute as potential colonizers of the peridomestic environment. Increasing the distance between the peridomestic structures and the sylvatic environment as much as possible appears to be a simple and feasible recommendation to reduce the contact rate between humans and infected bugs and ultimately Chagas disease transmission.

Actualización de la distribución geográfica de Triatoma dispar (Hemiptera: Reduviidae: Triatominae) en Ecuador

Se registra por primera vez la especie Triatoma dispar a una altitud de 1.200 msnm en la localidad de Milpe km 90, Cantón San Miguel de los Bancos, Provincia de Pichincha y se actualiza su distribución geográfica en el Ecuador. Los triatominos se colectaron durante un estudio de flebótomos (vectores de Leishmania), en peridomicilio y remanentes de bosque. Milpe km 90 no presentó evidencia clínica, ni transmisión de la enfermedad de Chagas o circulación enzoótica de Trypanosoma cruzi; sin embargo, se encuentra en una zona de riesgo epidemiológico alto. El presente trabajo contribuye al inventario de la fauna de triatominos del Ecuador y a la actualización de la distribución geográfica de T. dispar, una especie silvestre con potencial rol vectorial, que ya ha colonizado ambientes domésticos y peridomésticos en Esmeraldas y Loja.

Exploring the molecular complexity of Triatoma dimidiata sialome

Triatoma dimidiata, a Chagas disease vector widely distributed along Central America, has great capability for domestic adaptation as the majority of specimens caught inside human dwellings or in peridomestic areas fed human blood. Exploring the salivary compounds that overcome host haemostatic and immune responses is of great scientific interest. Here, we provide a deeper insight into its salivary gland molecules. We used high-throughput RNA sequencing to examine in depth the T. dimidiata salivary gland transcriptome. From >51 million reads assembled, 92.21% are related to putative secreted proteins. Lipocalin is the most abundant gene family, confirming it is an expanded family in Triatoma genus salivary repertoire. Other putatively secreted members include phosphatases, odorant binding protein, hemolysin, proteases, protease inhibitors, antigen-5 and antimicrobial peptides. This work expands the previous set of functionally annotated sequences from T. dimidiata salivary glands available in NCBI from 388 to 3815. Additionally, we complemented the salivary analysis through proteomics (available data via ProteomeXchange with identifier PXD008510), disclosing the set complexity of 119 secreted proteins and validating the transcriptomic results. Our large-scale approach enriches the pharmacologically active molecules database and improves our knowledge about the complexity of salivary compounds from haematophagous vectors and their biological interactions. SignificanceSeveral haematophagous triatomine species can transmit Trypanosoma cruzi, the etiological agent of Chagas disease. Due to the reemergence of this disease, new drugs for its prevention and treatment are considered priorities. For this reason, the knowledge of vector saliva emerges as relevant biological finding, contributing to the design of different strategies for vector control and disease transmission. Here we report the transcriptomic and proteomic compositions of the salivary glands (sialome) of the reduviid bug Triatoma dimidiata, a relevant Chagas disease vector in Central America. Our results are robust and disclosed unprecedented insights into the notable diversity of its salivary glands content, revealing relevant anti-haemostatic salivary gene families. Our work expands almost ten times the previous set of functionally annotated sequences from T. dimidiata salivary glands available in NCBI. Moreover, using an integrated transcriptomic and proteomic approach, we showed a correlation pattern of transcription and translation processes for the main gene families found, an important contribution to the research of triatomine sialomes. Furthermore, data generated here reinforces the secreted proteins encountered can greatly contribute for haematophagic habit, Trypanosoma cruzi transmission and development of therapeutic agent studies.

16S rRNA gene amplicon sequencing reveals dominance of Actinobacteria in Rhodnius pallescens compared to Triatoma maculata midgut microbiota in natural populations of vector insects from Colombia

Chagas disease affects more than 6 million people in Latin America, it is a parasitic disease caused by the protozoan Trypanosoma cruzi, which is transmitted mainly by bloodsucking insects of the Triatominae subfamily. Studies on microbial communities that inhabit the insect gut are important to understanding their role in the parasite transmission and development. The present work aims to evaluate the gut bacterial composition of natural populations of triatomine species from Vichada and Magdalena, administrative states called departments in Colombia, using high-throughput sequencing technologies. The insects were collected from housing peridomestic area and Attalea butyracea palms; they were identified by conventional taxonomy as Triatoma maculata and Rhodnius pallescens, and their guts were dissected under aseptic conditions in order to obtain total DNA. After DNA quality confirmation, the sequencing of the V4 region of 16S rRNA gene was carried out using the Illumina platform MiSeq. The results showed that 13 predominant bacterial genera were present in both species, being Burkholderia, Gordonia, and Ralstonia, the most prevailing bacterial genera. Furthermore, representative genera of each species were found. Williamsia and Kocuria were the most common in R. pallescens; and Dietzia, Aeromonas, and Pelomonas were only observed in T. maculata samples. This is the first study of microbiota associated with these triatomine species using massive sequencing methods The approach allowed inferring the presence of a dominant population of bacteria according to the triatomine species in Colombia, which may suggest a strong association between microbiota and their host.

Biology of the introduced species Triatoma lecticularia (Hemiptera: Reduviidae) to northwestern Mexico, under laboratory conditions

The first record of Triatoma lecticularia out of its reported distribution area together with the brief description of the said area is provided in this paper. In addition, some biological parameters related to hatching of eggs, life cycle and feeding and defecation behaviors for each instar of one population of T. lecticularia from its previously reported distribution area (PR) and for each instar of that introduced recently found population (IS) of this species were evaluated and compared. Twenty-eight specimens were collected from IS, mostly (64.29%) from peridomestic areas (mainly chicken coops). No significant (p>0.05) differences were recorded between the two studied cohorts in their average time to hatch, which was close to 19days. The median egg-to-adult development time, the number of blood meals at each nymphal, the instar mortality rates and median time-lapse for beginning of feeding were significantly (p<0.05) shorter for the IS cohort. Median feeding time was higher in PR. Defecation delay was shorter than 10min in both studied cohorts. Given these results, the introduced recently found population of T. lecticularia could be considered an important potential vector of Trypanosoma cruzi to human populations and could replace main triatomine species on its new distribution area.

Phlebotomines in an area endemic for American cutaneous leishmaniasis in northeastern coast of Brazil.

Phlebotomines have worldwide distribution with many species present in Brazil, including the northeastern region, where the fauna is very diverse. The aim of this study was to identify the sandfly fauna in an area endemic for American cutaneous leishmaniasis (ACL) in the state of Pernambuco. Sandflies were caught on three consecutive nights every month from October 2015 to September 2016, from 5 pm to 5 am, using seven light traps of Centers for Disease Control (CDC) type. Females were identified and used for molecular Leishmania detection. A total of 2,174 specimens belonging to ten species were collected: Lutzomyia choti (88.2%; 1,917/2,174) was the most abundant species, followed by Lutzomyia whitmani (8.1%; 176/2,174) and Lutzomyia sordellii (1.5%; 33/2,174). The majority of the specimens were collected in peridomestic areas (64.1%; 1,394/2,174) and during the rainy period. All the samples examined were negative for Leishmania spp. The presence of Lutzomyia whitmani indoors and in peridomestic areas indicates that the inhabitants of this area are exposed to the risk of infection by the parasites responsible for ACL.