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The objective of this study was to morphologically characterize the structures suggestive of gregarines found in the feces of Triatoma dimidiata collected in five municipalities in Yucatan, Mexico. Three hundred ninety-six specimens of T. dimidiata collected during 2022 and 2023 were analyzed, of which 8.84 % (n = 35) showed evidence of infection by a gregarine in the intestine and 1.77 % (n = 7) of infection with vermiform gregarine in Malpighian tubules. With microscopic examination, it was possible to obtain measurements and micrographs that allowed the rediscovery of Machadoella triatomae (vermiform gregarine) as well as a potential new gregarine species not previously described in T. dimidiata, which, based on its morphological characteristics, could be another Schizogregarina of the genus Caulleryella (flask-shaped). Additionally, the dissections of some specimens helped correctly identify the site where these gregarines parasitized T. dimidiata. Furthermore, of the three staining techniques used in this study, Lugol's solution and Wright's stain provided greater contrast and were therefore useful for visualizing these microorganisms. Scanning electron microscopy of the new gregarine revealed the three-dimensional shape of merozoites inside and outside a ruptured meront in detail. This study provides morphological evidence of two gregarines (Phylum: Apicomplexa) parasitizing Triatoma dimidiata in multiple regions of Yucatan, Mexico. M. triatomae was isolated in Malpighian tubules, and another gregarine, possibly of the genus Caulleryella, was isolated in the intestine., Competing Interests: Declaration of competing interest The authors of this article declare that they have no conflicts of interest that could influence the objectivity or integrity of the presented research. They have no financial affiliations or personal relationships with organizations or entities that could inappropriately influence scientific work., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aedes albopictus (Skuse) is a competent vector of dengue and Zika viruses in Mexico. Monitoring the level of resistance of local population is essential due to its epidemiological significance. This study aimed to identify mutations in the voltage-gated sodium channel (VGSC) as one of the mechanisms responsible for pyrethroid insecticide resistance in Ae. albopictus. Immature samples were collected in a rural town in Yucatan, Mexico, from May to October 2021. The pyrethroid insecticide lambda-cyhalothrin was impregnated in CDC bottles and bioassays were conducted on Ae. albopictus populations 3-5 days after emergence. The mosquitoes were susceptible to the insecticide. Females were taken for total DNA extraction. Fragments of domains II, III, and IV of the voltage-gated sodium channel (VGSC) were amplified and sequenced. The presence of synonymous and non-synonymous mutations was found in positions 1532 and 1534 of domain III of the sodium channel gene (VGSC). No mutant alleles in domain IV were detected. A homozygous mutant (ACG) coding for the amino acid threonine (1008Thr) was identified in domain II. Domain III included three heterozygous alleles (P1528S, L1530S, and Ile1410Thr). This last heterozygous allele is reported for the first time in Mexico. Homozygous mutants encoding the amino acids serine/serine and serine/proline in domain III were observed. These have been reported in Aedes aegypti from Mexico, but not yet in Ae. albopictus. This represents new findings for the region, as Ae. albopictus has only been introduced there for approximately five years. In conclusion, non-synonymous mutations were found in Ae. albopictus in a rural area of Yucatan, emphasizing the importance of integrated vector control to prevent Asian tiger mosquitoes from spreading these resistant alleles.

The genus Flavivirus (Family: Flaviviridae) comprises arboviruses with the capacity to infect humans and animals. It also integrates insect-specific viruses. This study aimed to identify Flavivirus in mosquitoes captured in 17 municipalities in Yucatan State, Mexico. The mosquitoes were caught in households from November 2021 to May 2022. A total of 4,321 adult mosquitoes from five species were caught. The most abundant were Culex quinquefasciatus (n = 3,563) and Aedes aegypti (n = 734). For molecular investigations, 600 female mosquitoes were split into groups of 10, mostly for species and site location. Reverse transcriptase polymerase chain reaction (RT-PCR) amplified a region of the NS5 gene to find the Flavivirus ribonucleic acids (RNA). A total of 24 pools that were positive for Flavivirus were detected in Ae. aegypti specimens and subsequently subjected to sequencing using the Sanger method. A total of 12 sequences matched the established quality criteria and were subsequently employed for sequence homology analysis. We found that one sequence corresponded to the Zika virus (ZIKV), and 11 sequences had sequence similarity with Phlebotomus-associated flavivirus (PAFV), an insect-specific virus (ISF). In conclusion, we found ZIKV in the Merida municipality, Yucatan State, which suggests that the virus is silently circulating. Phlebotomus-associated flavivirus is distributed in five municipalities in Yucatan State, Mexico. Future studies could focus on isolating this virus and studying its biological role within Ae. aegypti.

The Yucatan Peninsula is a biogeographic province of the Neotropical region which is mostly encompassed by the 3 Mexican states of Campeche, Quintana Roo, and Yucatán. During the development of the International Joint Laboratory ELDORADO (Ecosystem, bioLogical Diversity, habitat mOdifications and Risk of emerging PAthogens and Diseases in MexicO), a French-Mexican collaboration between the IRD (Institut de Recherche pour le Développement) and UNAM (Universidad Nacional Autónoma de México) in Mérida, it became evident that many putative mosquito species names recorded in the Mexican Yucatan Peninsula were misidentifications/misinterpretations or from the uncritical repetition of incorrect literature records. To provide a stronger foundation for future studies, the mosquito fauna of the Mexican Yucatan Peninsula is here comprehensively reviewed using current knowledge of taxonomy, ecology, and distribution of species through extensive bibliographic research, and examination of newly collected specimens. As a result, 90 mosquito species classified among 16 genera and 24 subgenera are recognized to occur in the Mexican Yucatan Peninsula, including 1 new peninsula record and 3 new state records., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Triatoma dimidiata is a species complex, and its members are responsible for the transmission of Trypanosoma cruzi , the causative agent of Chagas disease. We present the assembly and annotation of the mitogenome of the Triatoma dimidiata (Latreille, 1811) and Triatoma huehuetenanguensis Lima-Cordón & Justi, 2019. The mitochondrial genomes were successfully sequenced using the Illumina Nextseq 500 platform, 2×75 cycles, and 5 million reads per sample. Contigs were assembled and annotated using the reference genomes of T. dimidiata and T. huehuetenanguensis available in Genbank (NC_002609 and NC_050325.1, respectively). The mitogenomes of T. dimidiata have lengths of 17,008 bp, while those of T. huehuetenanguensis are 15,910 bp and 15,909 bp. The genome comprises 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a control region. The mitogenomes will be valuable to scholars and students focused on integrative taxonomy, phylogeography, and evolutionary studies of the Triatoma dimidiata complex and the transmission of Chagas diseases., (© 2023 The Author(s).)

The surveillance of arboviruses in mangrove mosquitoes is a neglected topic in Mexico. The Yucatan State is part of a peninsula and, therefore, is rich in mangroves along its coast. The purpose of the study was to identify alphavirus in the mosquito fauna of mangroves. Mosquitoes were captured in mangrove settings in seven communities in Yucatan between June 2019 and August 2021. From 1900 to 2200 h and from 0500 to 0800 h, mosquitoes were captured with a backpack-mounted aspirator. In total, 3,167 female mosquitoes of five genera and nine species were captured. Aedes taeniorhynchus and Anopheles crucians were the most abundant mosquitoes collected. Mosquitoes were sorted into 210 pools and tested by reverse transcription-polymerase chain reaction for alphavirus ribonucleic acid (RNA). Alphavirus RNA was found in Ae. taeniorhynchus, An. pseudopunctipennis, and An. crucians collected in the Celestun Mangrove. The community is part of the Ria Celestun Biosphere Reserve, and the presence arbovirus-infected mosquitoes could pose a health risk to residents and visitors alike in the area., (Copyright © 2023 by The American Mosquito Control Association, Inc.)

Several known mosquito species occur in the Mexican state of Yucatan, including competent and suspected vectors responsible for transmitting zoonotic arboviruses. Between February and July 2022, mosquito collections were carried out in several forested areas in Yucatan. As part of the ongoing monitoring, we present the first reports of Culex (Microculex) rejector and Cx. (Anoedioporpa) restrictor. Another 14 species were identified during the monitoring: Aedes albopictus, Ae. bimaculatus, Ae. tormentor, Ae. cozumelensis, Anopheles albimanus, Cx. coronator s.l., Cx. erraticus, Cx. lactator, Cx. salinarius, Coquillettidia venezuelensis, Limatus durhamii, Psorophora ciliata, Toxorhynchites theobaldi, and Wyeomyia mitchellii. Currently, the mosquito fauna in Yucatan consists of 65 species. The subgenera Microculex and Anoedioporpa had not been documented in Yucatan State prior to the current investigation., (Copyright © 2023 by The American Mosquito Control Association, Inc.)

Background: Hematophagous mites affect numerous bird species, causing severe injuries to the budgerigars. Some species can cause dermatitis in humans., Aims: The purpose was to morphologically identify the mites related to budgerigars ( Melopsittacus undulatus) and their nests in Yucatan, Mexico., Methods: In May 2022, a private budgerigar hatchery was visited and mites were collected from the bodies of the birds and their nests. The morphological traits of the mites were confirmed by scanning electron microscopy., Results: Four of 30 birds showed severe clinical signs of mite infestation. The Budgerigars revealed lesions in the cere, nostrils, eyelids, beak, and paws. The bird's skin showed signs of dryness and beige coloring. The birds with severe damage also presented anorexia and had deformed paws and beaks. The parasitosis was caused by the "burrowing mites," Knemidocoptes pilae . The burrowing mites and the Grallacheles bakeri were recovered and identified from paw scabs. To eliminate mites, a topical application of Ivermectin was administered to the necks of the birds. The dose was a single, which has a residuality of 21 days. Two drops (0.115 mg/ml) of ivermectin were applied to each bird. A gradual reduction in crusted lesions due to mite mortality was noted. The "tropical fowl mite" Ornithonyssus bursa was identified in the nests, which represents the first record in Mexico., Conclusions: Three species of mites were discovered in a single budgerigar hatchery. This emphasizes the importance of deworming birds and keeping a clean environment in their cages to reduce the potential for parasitic mite infestation., Competing Interests: The authors have no conflict of interest to declare.

Backyard animal husbandry is common in rural communities in developing countries and, given the conditions in which it occurs, it can increase the risk of disease transmission, such as arboviruses. To determine the presence of the Zika virus (ZIKV) and abundance of its arthropod vectors we evaluated the socioeconomic implications involved in its transmission in two highly vulnerable Mayan communities in the state of Yucatan that practice backyard farming. An analytical cross-sectional study was carried out throughout 2016 to understand socioeconomic variables and seasonal patterns in mosquito populations. We selected 20 households from each community. Social exclusion indicators were analyzed, human and domestic animals were sampled, and mosquitoes were collected and identified. Four out of eight indicators of social exclusion were higher than the reported national averages. We captured 5,825 mosquitoes from 16 species being Culex quinquefasciatus and Aedes aegypti the most abundant. The presence of chickens and human overcrowding in dwellings were the most significant factors ( P = 0.026) associated with the presence of Ae. aegypti . Septic tanks (odds ratio = 6.64) and chickens (odds ratio = 27.41) in backyards were the main risk factors associated with the presence of immature states of Ae. aegypti in both communities. Molecular analysis to detect ZIKV was performed in blood samples from 416 humans, 1,068 backyard animals and 381 mosquito pools. Eighteen humans and 10 pig pools tested positive for ZIKV. Forty-three mosquito pools tested positive for flavivirus. Ten of the 43 pools of positive mosquitoes were sequenced, corresponding 3/10 to ZIKV and 1/10 to Dengue virus type 2. The findings obtained indicate the continuous circulation of Flavivirus (including ZIKV) in backyard environments in vulnerable communities, highlighting the importance of studying their transmission and maintenance in these systems, due that backyard animal husbandry is a common practice in these vulnerable communities with limited access to health services., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lopez-Apodaca, Zarza, Zamudio-Moreno, Nuñez-Avellaneda, Baak-Baak, Reyes-Solis, Oswaldo Margarito, Peláez-Ballestas, Roiz, Suzán, Roche and Machain-Williams.)

Triatomines are vectors of American Trypanosomiasis also known as Chagas´ disease where several reservoirs including dogs are involved in the transmission cycle of the causal agent (Trypanosoma cruzi). Considering that the prevalence of American trypanosomiasis in dogs is higher than in humans and that dogs in addition are susceptible of this disease, and are involved in peridomestic transmission to humans, the search for new alternatives for vector control of the triatomines responsible for transmission in dogs is required. Over the 20 weeks the study lasted, 600 individual female, adult of Rhodnius prolixus were offered to the 15 dogs treated with a single oral dose of Fluralaner (Bravecto®, MSD). Feeding pattern of triatomines was not affected by the treatment during the whole study. The fluralaner-induced mortality of R. prolixus had a significant effect until week 12 at which time 100% mortality was observed. Mortality decreased to 67.5% at week 16 to practically nil 0.8% on week 20. Fluralaner achieved 100% mortality of triatomines between 12- and 48-h post-feeding. It was demonstrated that a single oral dose of fluralaner in dogs is highly effective in producing mortality in adult R. prolixus for the time guaranteed by the manufacturer for other blood-sucking insects, with a considerable effective residual effect for up to 16 weeks. Due to this high efficacy, fluralaner could be considered in strategies to control the transmission vectors of Chagas disease in dogs and in turn decrease the peri-domestic transmission cycle, particularly in hyperendemic areas., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Dengue cases and deaths occur frequently in Mexico, although the trend is not uniform across the country. We performed a Spatio-temporal analysis of dengue cases and deaths in Mexico from 2007 to 2020, and clustered states according to whether there was a low, moderate, or high risk of dengue. A total of 501,600 confirmed dengue cases were registered from 2007 to 2020, with 378,122 cases classified as dengue fever (DF) and 123,478 cases classified as dengue hemorrhagic fever (DHF). For each confirmed case, there were 4.68 probable cases. There were 1,230 dengue deaths, with highest numbers reported in 2009, 2012, 2013, and 2019. The number of deaths had a significant correlation (P ≤ 0.01) with DF (r = 0.82), DHF (r = 0.94), and probable dengue cases (r = 0.84). States were clustered using Machine Learning technique according to select indices associated with dengue. Cluster 1 (low risk) primarily contained states in the northwest, northcentral, and east. Cluster 2 (moderate risk) includes states in the northeast. Cluster 3 (high risk) mostly contained coastal states in the southeast, southwest, and west. The generation of the clusters was supported by the Kruskal-Wallis test. A significant difference was found in the incidence, mortality rates, and case-fatality rates of dengue among the clusters (P ≤ 0.01). Notably, cluster 3 contributed 71.4% of the confirmed cases and 89.2% of the deaths. Public health and vector control strategies designed to mitigate the burden of dengue in Mexico should consider the states in cluster 3 as high priority areas.

Introduction: SARS-CoV-2 infection spatial and temporal distribution overlaps with endemic areas of vector-borne diseases (VBD), whose surveillance in Mexico has substantially changed since the first COVID-19 confirmed case., Objectives: To estimate and compare the incidence rates of VBDs before and after the introduction of SARS-CoV-2 in Mexico., Methods: Retrospective study of VBD cases from 2014 to 2021. The incidence rates of each VBD in the period before (2014-2019) and after (2020-2021) the introduction of SARS-CoV-2 in Mexico were calculated and compared., Results: Before the introduction of SARS-CoV-2, the incidence rates of VBDs were high and after the introduction of coronavirus there was a decrease in epidemiological indices; however, there was only statistically significant difference in the incidence rate of malaria (p ≤ 0.05) and other rickettsiae (p ≤ 0.05)., Conclusions: Some measures to reduce COVID-19 cases, such as social distancing, home confinement, reductions in public transport and working at home (home office), probably temporarily decreased the number of VBD cases; however, there may be a resurgence of VBDs in the near future., (Copyright: © 2022 Permanyer.)

Aedes ( Stegomyia ) albopictus is a mosquito native to Southeast Asia. Currently, it has a wide distribution in America, where natural infection with arboviruses of medical and veterinary importance has been reported. In spite of their importance in the transmission of endemic arbovirus, the basic information of parameters affecting their vectorial capacity is poorly investigated. The aim of the work was to update the distribution range of Ae. albopictus in the Americas, review the blood-feeding patterns, and compare the minimum infection rate (MIR) of the Dengue virus (DENV) between studies of vertical and horizontal transmission. The current distribution of Ae. albopictus encompasses 21 countries in the Americas. An extensive review has been conducted for the blood-feeding patterns of Ae. albopictus . The results suggest that the mosquito is capable of feeding on 16 species of mammals and five species of avian. Humans, dogs, and rats are the most common hosts. Eight arboviruses with the potential to infect humans and animals have been isolated in Ae. albopictus . In the United States of America (USA), Eastern equine encephalitis virus, Keystone virus, La Crosse Virus, West Nile virus, and Cache Valley virus were isolated in the Asian mosquito. In Brazil, Mexico, Colombia, and Costa Rica, DENV (all serotypes) has been frequently identified in field-caught Ae. albopictus . Overall, the estimated MIR in Ae. albopictus infected with DENV is similar between horizontal (10.95) and vertical transmission (8.28). However, in vertical transmission, there is a difference in the MIR values if the DENV is identified from larvae or adults (males and females emerged from a collection of eggs or larvae). MIR estimated from larvae is 14.04 and MIR estimated in adults is 4.04. In conclusion, it has to be highlighted that Ae. albopictus is an invasive mosquito with wide phenotypic plasticity to adapt to broad and new areas, it is highly efficient to transmit the DENV horizontally and vertically, it can participate in the inter-endemic transmission of the dengue disease, and it can spread zoonotic arboviruses across forest and urban settings.

Background: Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) with an urban transmission cycle that primarily involves humans and Aedes aegypti. Evidence suggests that the evolution of some arboviruses is constrained by their dependency on alternating between disparate (vertebrate and invertebrate) hosts. The goals of this study are to compare the genetic changes that occur in ZIKV after serial passaging in mosquito or vertebrate cell lines or alternate passaging in both cell types and to compare the replication, dissemination, and transmission efficiencies of the cell culture-derived viruses in Ae. aegypti., Methods: An isolate of ZIKV originally acquired from a febrile patient in Yucatan, Mexico, was serially passaged six times in African green monkey kidney (Vero) cells or Aedes albopictus (C6/36) cells or both cell types by alternating passage. A colony of Ae. aegypti from Yucatan was established, and mosquitoes were challenged with the cell-adapted viruses. Midguts, Malpighian tubules, ovaries, salivary glands, wings/legs and saliva were collected at various times after challenge and tested for evidence of virus infection., Results: Genome sequencing revealed the presence of two non-synonymous substitutions in the premembrane and NS1 regions of the mosquito cell-adapted virus and two non-synonymous substitutions in the capsid and NS2A regions of both the vertebrate cell-adapted and alternate-passaged viruses. Additional genetic changes were identified by intrahost variant frequency analysis. Virus maintained by continuous C6/36 cell passage was significantly more infectious in Ae. aegypti than viruses maintained by alternating passage and consecutive Vero cell passage., Conclusions: Mosquito cell-adapted ZIKV displayed greater in vivo fitness in Ae. aegypti compared to the other viruses, indicating that obligate cycling between disparate hosts carries a fitness cost. These data increase our understanding of the factors that drive ZIKV adaptation and evolution and underscore the important need to consider the in vivo passage histories of flaviviruses to be evaluated in vector competence studies.

The morphological characterization of ectoparasites from domestic and wild animals is crucial to distinguish those that may be involved in the transmission of zoonotic pathogens. The objectives of this work were to identify parasitic arthropods collected from several hosts in Yucatan State, Mexico and to determine the prevalence of the parasite Trypanosoma cruzi in sylvatic specimens of Triatoma dimidiata. Morphological traits and scanning electron microscopy were used to confirm some parasitic identities. In total, 834 parasitic arthropods of various taxa were identified. Amblyomma americanum, Amblyomma maculatum, Amblyomma parvum, Dermacentor variabilis, and Rhipicephalus sanguineus were identified from dogs, horses, sheep, and deer. The flea Ctenocephalides felis was identified from dogs and the human flea, Pulex irritans was found on horses and sheep. The Neotropical deer ked Lipoptena mazamae was identified from brown brocket deer Mazama pandora. The chewing lice Chelopistes meleagridis, Menacanthus stramineus, Menopon gallinae, Myrsidea sp. and Lipeurus caponis were identified from poultry (Meleagris gallopavo and Gallus gallus). Other chewing lice, Tyranniphilopterus sp., Columbicola columbae, and Physconelloides eurysema were identified from wild birds Pachyramphus aglaiae, Patagioenas flavirostris and Zenaida asiatica, respectively. Trypanosoma cruzi was present in 52.5% of sylvatic adult T. dimidiata. Several of these findings represent new records of ectoparasites for Yucatan and new distribution areas in Mexico. The implications for human and animal health are discussed.

This study was carried out to identify the ectoparasites that infest owned dogs in the state of Tabasco, Mexico. In total, 1,302 dogs were sampled in the 5 ecological regions of Tabasco. The dog owners were surveyed to identify the factors associated with infestations. Ectoparasites were identified using taxonomic keys. Eleven species of ectoparasites were observed. General prevalence was 26.65%. Rhipicephalus sanguineus and Ctenocephalides felis were the most prevalent and abundant ectoparasites. The most important factors associated with ectoparasite infestations in the studied dogs were living outdoors, being a non-purebred, having short hair, being dark-haired, and having a body condition <3. Ectoparasite studies such as the one presented herein generate important information to create control programs focused on decreasing infestations in companion animals and thus the likelihood of zoonotic transmission of pathogens., (© American Society of Parasitologists 2021.)

Introduction: Dirofilaria immitis is a nematode that affects human health in several countries of the world. This study was conducted to examine whether serum samples from the owners of microfilaremic dogs present immunoreactivity to parasite proteins., Methodology: Eight serum samples from the owners of microfilaremic dogs were examined. Total proteins were extracted from adult worms and 12% SDS-PAGE was performed. The gel was electroblotted to a nitrocellulose membrane, and a Western blot (WB) was performed. Reactive bands of 22, 33, 39, 49, and 63 kDa in WB were excised from the gel and analyzed by mass spectrometry (MS)., Results: The MS results showed the presence of 10 different proteins of D. immitis recognized by the human serum samples., Conclusions: These results indicate that in endemic areas of D. immitis, owners of infected dogs recognize specific proteins of the parasite, suggesting a possible infection., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2020 Oswaldo M Torres-Chable, Ligia G Brito-Argaez, Ignacio R Islas-Flores, Claudia V Zaragoza-Vera, Maritza Zaragoza-Vera, Guadalupe Arjona-Jimenez, Carlos M Baak-Baak, Nohemi Cigarroa-Toledo, Roberto Gonzalez-Garduño, Carlos I Machain-Williams, Julian E Garcia-Rejon.)

The present study was carried out to identify Rickettsia species with zoonotic potential in ticks collected from dogs in a rural area in Tabasco, Mexico. In total 197 Amblyomma maculatum ticks were collected from 40 domestic dogs. The collected specimens were pooled and subjected to DNA extraction. A fragment (380 bp) of citrate synthase gene (gltA) was amplified by polymerase chain reaction (PCR) using universal primers for Rickettsia. A second PCR was later performed to amplify a fragment (420 bp) of the outer membrane protein B gene (ompB). The PCR products were purified, sequenced and compared using the basic local alignment search tool (BLAST). Twenty out of 40 (50%) tick pools assayed were positive for rickettsial DNA using both primer pairs. The consensus sequence obtained from the ompB gene fragments showed 99.5-100% of identity with strains of Rickettsia parkeri. This study provides the first molecular evidence of the presence of R. parkeri in A. maculatum ticks infesting domestic dogs from southeastern Mexico. Close contact between dogs and humans should lead to consider the infection caused by this species of Rickettsia among the differential diagnoses for people of Tabasco, Mexico, who show acute febrile syndrome associated to inoculation eschar and have a clinical history of tick exposure.

Competing Interests: None

This study was designed to assess whether churches in endemic dengue districts in Merida, Mexico provide suitable breeding habitats for mosquitoes and are potential sites for dengue virus (DENV) transmission. Churches were inspected for immature and adult mosquitoes once every week from November 2015 to October 2016. A total of 10,997 immatures of five species were collected. The most abundant species were Aedes aegypti (6,051) and Culex quinquefasciatus (3,018). The most common source of immature Ae. aegypti were buckets followed by disposable containers. Adult collections yielded 21,226 mosquitoes of nine species. The most common species were Cx. quinquefasciatus (15,215) and Ae. aegypti (3,902). Aedes aegypti were found all year long. Female Ae. aegypti (1,380) were sorted into pools (166) and assayed for flavivirus RNA by RT-PCR and Sanger sequencing. Two pools were positive for DENV (DENV-1 and 2). In conclusion, we demonstrated that some churches in Merida are infested with mosquitoes all year long and they potentially serve as sites for DENV transmission and should therefore be considered for inclusion in mosquito and arboviruses control and surveillance efforts.

Culex quinquefasciatus Say (Diptera: Culicidae) is a mosquito species that has attracted a lot of attention from a medical and veterinary point of view; however, little is known about the frequency of L1014F mutations that have been found in the sodium channel gene, with this being a target for DDT and pyrethroid insecticides. The distribution and frequency of the L1014F mutation in Cx. quinquefasciatus populations was determined in rural and urban areas of Yucatan, Mexico from January 2015 to March 2016. Nine hundred fifty adult females out of 17,727 immature states were collected and analyzed in all sites sampled (n = 10). Susceptible homozygotes were identified (L1014/L1014) in 12% (114/950), heterozygous individuals (F1014/L1014) in 34% (323/950), and mutated homozygotes (F1014/F1014) in 54% (513/950) during the dry and rainy seasons. In this work, study areas with a high frequency of L1014F mutation were identified. These findings may help guarantee a more effective and efficient use of the resources available for the control of this vector.

We fully sequenced the genome of Houston virus, a recently discovered mosquito-associated virus belonging to the newly established family Mesoniviridae. The isolate was recovered from Culex quinquefasciatus in southern Mexico, which shows that the geographic range of Houston virus is not restricted to the United States in North America.

Aedes aegypti is the vector of the arboviruses causing dengue, chikungunya and zika infections in Mexico. However, its presence in public places has not been fully evaluated. In a cemetery from Merida, Yucatan, Mexico, the productivity of Ae. aegypti, the gonotrophic cycle, and the presence of Ae. aegypti females infected with arboviruses were evaluated. Immature and adult mosquitoes were inspected every two months between April 2016 to June 2017. For the gonotrophic cycle length, the daily pattern of total and parous female ratio was registered and was analyzed using time series analysis. Ae. aegypti females were sorted into pools and assayed for flavivirus RNA by RT-PCR and Sanger sequencing. Aedes aegypti immatures represented 82.86% (8,627/10,411) of the collection. In total, 1,648 Ae. aegypti females were sorted into 166 pools. Two pools were positive; one for dengue virus (DENV-1) and the other for zika virus (ZIKV). The phylogenetic analysis revealed that the DENV-1 is more closely related to isolates from Brazil. While ZIKV is more closely related to the Asian lineage, which were isolates from Guatemala and Mexico. We report some evidence of vertical transmission of DENV-1 in nulliparous females of Ae. aegypti. The gonotrophic cycle was four and three days in the rainy and dry season, respectively. The cemetery of Merida is an important focus of Ae. aegypti proliferation, and these environments may play a role in arboviruses transmission; probably limiting the efficacy of attempts to suppress the presence of mosquitoes in domestic environments.

Background & Objectives: Dirofilaria immitis is a filarial nematode that causes heartworm disease in domestic as well as wild canines and felines; and cutaneous or pulmonary infections in humans. The purpose of the study was to estimate the prevalence of D. immitis in domestic dogs in Tabasco, Mexico and to assay mosquitoes temporally and spatially associated with dogs for evidence of infection., Methods: Blood was collected from 1050 dogs in 1039 houses during a random household survey performed in 2016 and 2017. Genomic DNA was extracted and assayed by polymerase chain reaction (PCR) using pan-filarial primers and various species-specific primers. Dog owners were interviewed using a structured questionnaire designed to collect information on factors that may impact the occurrence of filarial infection. The association between canine dirofilariasis prevalence and factors likely to impact infection was determined by univariate logistic regression analysis, followed by multivariate binomial logistic regression analysis. Indoor and outdoor resting mosquitoes were collected from houses by manual aspiration. Mosquitoes were identified according to species, homogenized and tested by PCR for filarial nematodes., Results: A total of 84 (8%) dogs were positive for D. immitis DNA, while 3 (0.3%) dogs contained Acanthocheilonema reconditum DNA. Several factors were significantly associated with D. immitis infection. For example, dogs that lived <100 m from a large source of open standing water were significantly more likely (p = 0.002) to become infected with D. immitis than other dogs. Additionally, dogs with infrequent or no anthelmintic treatment were significantly more likely (p = 0.0) to become infected than dogs that were regularly treated. The entomologic investigation yielded 2618 female mosquitoes from 14 species. Four pools of Culex quinquefasciatus were positive for D. immitis DNA and the minimum infection rate, calculated as the number of positive pools per 1000 mosquitoes tested, was 2.9., Interpretation & Conclusion: The study identified several factors positively associated with an increased risk of D. immitis infection in domestic dogs in Tabasco and provides evidence that Cx. quinquefasciatus is potentially an important vector in this region. This information can be used by local veterinarians and dog owners to reduce the burden of D. immitis on canine health., Competing Interests: The authors declare no conflicts of interest

To increase our understanding of the consequences of dengue virus infection during pregnancy, a retrospective analysis was performed on the medical records of all completed pregnancies (live births and pregnancy losses) at nine public hospitals in the Gulf of Mexico from January to October 2013. Eighty-two patients developed clinical, laboratory-confirmed dengue virus infections while pregnant. Of these, 54 (65.9%) patients were diagnosed with dengue without warning signs, 15 (18.3%) patients were diagnosed with dengue with warning signs, and 13 (15.9%) patients had severe dengue. Five (38.5%) patients with severe dengue experienced fetal distress and underwent emergency cesarean sections. Four patients delivered apparently healthy infants of normal birthweight while the remaining patient delivered a premature infant of low birthweight. Patients died of multiple organ failure during or within 10 days of the procedure. Severe dengue was also associated with obstetric hemorrhage (30.8%, four cases), preeclampsia (15.4%, two cases), and eclampsia (7.7%, one case). These complications were less common or absent in patients in the other two disease categories. Additionally, nonsevere dengue was not associated with maternal mortality, fetal distress, or adverse neonatal outcomes. In summary, the study provides evidence that severe dengue during pregnancy is associated with a high rate of fetal distress, cesarean delivery, and maternal mortality.

Competing Interests: There is no conflict of interest among the authors in the publication of this article

Blood-feeding status, gonotrophic cycle, and survival rates of Aedes (Stegmyia) aegypti (L.) was investigated in catholic churches from Merida, Yucatan. Female Ae. aegypti were caught using backpack aspirator during 25 consecutive days in rainy (2015) and dry season (2016). Blood-feeding status was determined by external examination of the abdomen and classified as unfed, fed, and gravid. Daily changes in the parous-nulliparous ratio were recorded, and the gonotrophic cycle length was estimated by a time series analysis. Also, was observed the vitellogenesis to monitoring egg maturity. In total, 408 females Ae. aegypti were caught, and there was a significant difference in the number of females collected per season (Z = -6.729, P ≤ 0.05). A great number was caught in the rainy season (n = 329). In the dry season, 79 females were caught, which the fed females were twice greatest than the unfed. The length of gonotrophic cycle was estimated on the base of a high correlation coefficient value appearing every 4 days in rainy at 26.7 ± 1.22°C, and 3 days in dry season at 29.8 ± 1.47°C. The daily survival rate of the Ae. aegypti population was higher in both seasons, 0.94 and 0.93 for the rainy and dry season, respectively. The minimum time estimated for developing mature eggs after blood feeding was similar in both seasons (3.5 days in rainy versus 3.25 days in dry). The measurement of the vectorial capacity of Ae. aegypti in catholic churches could help to understand the dynamics of transmission of arboviruses in sites with high human aggregation.

Background: Baseline hematologic data are used by veterinarians and wildlife biologists to perform health assessments on target animal species. Hematologic measurements are influenced by various factors including geography. Baseline hematologic RIs have been established for domestic water buffaloes (Bubalus bubalis) from various countries in the Eastern Hemisphere, but these data are not readily available for the Western Hemisphere., Objective: The aim of this study was to determine hematologic values for domestic water buffaloes from several commercial farms in southern Mexico., Methods: Blood was collected from 126 healthy, postlactating females (3 to 10 years old) from the Murrah breed, and 10 hematologic variables were measured., Results: Means, SDs, RIs, medians (MED), median absolute deviations (MAD), and other statistics were calculated for each hematologic variable. The MED (and MAD) for each variable are as follows: RBC count, 7.6 (1.1) × 10 12 /L; hemoglobin, 116.0 (13.3) g/L; PCV, 41.5 (7.6) %; MCV, 56.8 (7.0) fL; MCH, 14.6 (1.6) pg; MCHC, 250.0 (35.6) g/L; RDW (SD), 29.7 (5.5) fL; RDW (CV), 18.2 (1.4) %; reticulocytes, 0.0 (0.0) %, and WBC count, 12.4 (1.3) × 10 9 /L. These values were compared to those previously reported for water buffaloes from several countries in the Eastern Hemisphere and, on most occasions, they differed significantly., Conclusions: Our data can be used by veterinarians and other personnel involved in buffalo production in Mexico during medical evaluations., (© 2017 American Society for Veterinary Clinical Pathology.)

The majority of the Yucatán State, México, presents subtropical climate that is suitable for many species of mosquitoes that are known to be vectors of diseases, including those from the genera Aedes and Culex. The objective of this study is to identify the geographic distribution of five species from these two genera and estimate the human population at risk of coming in contact with them. We compiled distributional data for Aedes aegypti (L.), Aedes (Howardina) cozumelensis (Diaz Najera), Culex coronator Dyar and Knab, Culex quinquefasciatus Say, and Culex thriambus Dyar from several entomological studies in Yucatán between March 2010 and September 2014. Based on these data, we constructed ecological niche models to predict the spatial distribution of each species using the MaxEnt algorithm. Our models identified areas with suitable environments for Ae. aegypti in most of Yucatán. A similar percentage of urban (97.1%) and rural (96.5%) populations were contained in areas of highest suitability for Ae. aegypti, and no spatial pattern was found (Moran's I = 0.33, P = 0.38); however, we found an association of abundance of immature forms of this species with annual mean temperature (r = 0.19, P ≤ 0.001) and annual precipitation (r = 0.21, P ≤ 0.001). Aedes cozumelensis is also distributed in most areas of the Yucatán State; Cx. quinquefasciatus, Cx. coronator, and Cx. thriambus are restricted to the northwest. The information generated in this study can inform decision-making to address control measures in priority areas with presence of these vectors., (© The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The Peruvian Andes presents a climate suitable for many species of sandfly that are known vectors of leishmaniasis or bartonellosis, including Lutzomyia peruensis (Diptera: Psychodidae), among others. In the present study, occurrences data for Lu. peruensis were compiled from several items in the scientific literature from Peru published between 1927 and 2015. Based on these data, ecological niche models were constructed to predict spatial distributions using three algorithms [Support vector machine (SVM), the Genetic Algorithm for Rule-set Prediction (GARP) and Maximum Entropy (MaxEnt)]. In addition, the environmental requirements of Lu. peruensis and three niche characteristics were modelled in the context of future climate change scenarios: (a) potential changes in niche breadth; (b) shifts in the direction and magnitude of niche centroids, and (c) shifts in elevation range. The model identified areas that included environments suitable for Lu. peruensis in most regions of Peru (45.77%) and an average altitude of 3289 m a.s.l. Under climate change scenarios, a decrease in the distribution areas of Lu. peruensis was observed for all representative concentration pathways. However, the centroid of the species' ecological niche showed a northwest direction in all climate change scenarios. The information generated in this study may help health authorities responsible for the supervision of strategies to control leishmaniasis to coordinate, plan and implement appropriate strategies for each area of risk, taking into account the geographic distribution and potential dispersal of Lu. peruensis., (© 2017 The Royal Entomological Society.)

Chikungunya virus (CHIKV) was isolated from 12 febrile humans in Yucatan, Mexico, in 2015. One patient was co-infected with dengue virus type 1. Two additional CHIKV isolates were obtained from Aedes aegypti mosquitoes collected in the homes of patients. Phylogenetic analysis showed that the CHIKV isolates belong to the Asian lineage.

We conducted surveillance for flavivirus infection in peridomestic rodents in Merida, Mexico in 2011-12. We captured 161 rodents inside private residences, using Sherman traps, including 86 house mice (Mus musculus) and 75 black rats (Rattus rattus). Serum from each animal was assayed by plaque reduction neutralization test (PRNT) using two vertebrate-specific flaviviruses (Apoi and Modoc viruses) and five mosquito-borne flaviviruses (dengue 2, dengue 4, St. Louis encephalitis virus, West Nile, and yellow fever viruses). Sixty-one (37.9%) rodents had antibodies that neutralized at least one virus. Prevalences for flaviviruses were 64.0% and 15.1% for black rats and house mice, respectively. None of the PRNT90 titers exceeded 80, and often they were highest for Modoc virus. These data suggest that a subset of rodents had been infected with Modoc virus or a closely related flavivirus that was not included in the PRNT analysis.

The overall goal of this study was to estimate the prevalence of gastrointestinal (GI) parasites in dogs in the city of Villahermosa in Tabasco, Mexico. The study population consisted of 302 owned dogs that had limited access to public areas. A fecal sample was collected from each animal and examined for GI parasites by conventional macroscopic analysis and centrifugal flotation. Fecal samples from 80 (26.5%) dogs contained GI parasites. Of these, 58 (19.2%) were positive for helminths and 22 (7.3%) were positive for protozoan parasites. At least seven parasitic species were identified. The most common parasite was Ancylostoma caninum which was detected in 48 (15.9%) dogs. Other parasites detected on multiple occasions were Cystoisospora spp. (n = 19), Toxocara canis (n = 7) and Giardia spp. (n = 3). Three additional parasites, Dipylidium caninum, Trichuris vulpis and Uncinaria spp., were each detected in a single dog. No mixed parasitic infections were identified. In summary, we report a moderately high prevalence of GI parasites in owned dogs in Villahermosa, Tabasco. Several parasitic species identified in this study are recognized zoonotic pathogens which illustrates the important need to routinely monitor and treat dogs that live in close proximity to humans for parasitic infections.

We present data showing that structures serving as drains and catch basins for stormwater are important sources for production of the mosquito arbovirus vectors Aedes aegypti and Culex quinquefasciatus in Mérida City, México. We examined 1761 stormwater drains - located in 45 different neighborhoods spread across the city - over dry and wet seasons from March 2012 to March 2013. Of the examined stormwater drains, 262 (14.9%) held water at the time they were examined and 123 yielded mosquito immatures. In total, we collected 64,560 immatures representing nine species. The most commonly encountered species were Cx. quinquefasciatus (n=39,269) and Ae. aegypti (n=23,313). Ae. aegypti and Cx. quinquefasciatus were collected during all 11 months when we found water-filled stormwater drains, and both were found in stormwater drains located throughout Mérida City. We also present data for associations between structural characteristics of stormwater drains or water-related characteristics and the abundance of mosquito immatures. In conclusion, stormwater drains produce massive numbers of Ae. aegypti and Cx. quinquefasciatus across Mérida City, both in the wet and dry seasons, and represent non-residential development sites that should be strongly considered for inclusion in the local mosquito surveillance and control program., (Copyright © 2014. Published by Elsevier B.V.)

We examined the species composition and temporal occurrence of immature mosquitoes in containers and storm-water drains/catch basins from November 2011 to June 2013 in Mérida City, México. A wide range of urban settings were examined, including residential premises, vacant lots, parking lots, and streets or sidewalks with storm-water drains/catch basins. In total, 111,776 specimens of 15 species were recorded. The most commonly collected species were Aedes ( Stegomyia ) aegypti (L.) (n = 60,961) and Culex quinquefasciatus Say (45,702), which together accounted for 95.4% of the immatures collected. These species were commonly encountered during both rainy and dry seasons, whereas most other mosquito species were collected primarily during the rainy season. Other species collected were Aedes ( Howardina ) cozumelensis Diaz Najera, Aedes ( Ochlerotatus ) taeniorhynchus (Wiedemann), Aedes ( Ochlerotatus ) trivittatus (Coquillett), Culex coronator Dyar and Knab, Culex interrogator Dyar and Knab, Culex lactator Dyar and Knab, Culex nigripalpus Theobald, Culex salinarius Coquillett, Culex tarsalis Coquillett, Culex thriambus Dyar, Haemagogus equinus Theobald, Limatus durhamii Theobald, and Toxorhynchites rutilus (Coquillett). The greatest number of species was recorded from vacant lots (n = 11), followed by storm-water drains/catch basins (nine) and residential premises (six). Our study demonstrated that the heterogeneous urban environment in Mérida City supports a wide range of mosquito species, many of which are nuisance biters of humans and/or capable of serving as vectors of pathogens affecting humans or domestic animals. We also briefly reviewed the medical importance of the encountered mosquito species.

We assessed the potential for vacant lots and other nonresidential settings to serve as source environments for Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) in Mérida City, México. Mosquito immatures were collected, during November 2011-June 2013, from residential premises (n = 156 site visits) and nonresidential settings represented by vacant lots (50), parking lots (18), and streets or sidewalks (28). Collections totaled 46,025 mosquito immatures of 13 species. Ae. aegypti was the most commonly encountered species accounting for 81.0% of total immatures, followed by Culex quinquefasciatus Say (12.1%). Site visits to vacant lots (74.0%) were more likely to result in collection of Ae. aegypti immatures than residential premises (35.9%). Tires accounted for 75.5% of Ae. aegypti immatures collected from vacant lots. Our data suggest that vacant lots should be considered for inclusion in mosquito surveillance and control efforts in Mérida City, as they often are located near homes, commonly have abundant vegetation, and frequently harbor accumulations of small and large discarded water-holding containers that we now have demonstrated to serve as development sites for immature mosquitoes. In addition, we present data for associations of immature production with various container characteristics, such as storage capacity, water quality, and physical location in the environment.

Aedes (Stegomyia) aegypti is considered to be the most important dengue vector worldwide. Studies were conducted to design and evaluate a chemically-based baited ovitrap for monitoring Ae. aegypti under laboratory conditions. Several known chemical attractants and three types of ovitraps (ovitraps A, B, and C) were evaluated throughout the oviposition bioassays. Oviposition responses of gravid female Ae. aegypti were evaluated to n-heneicosane, 3-methylindole (skatole), 4-methylphenol (p-cresol), and phenol. Female Ae. aegypti were attracted to all the evaluated compounds. Among them, n-heneicosane at a concentration of 10 ppm (mg/l), skatole from 50 to 1000 ppm, p-cresol at 100 ppm, and phenol at 50 ppm showed a significant positive oviposition response. A blend of the four chemical attractants increased the oviposition response; 67% of the eggs were deposited in the treatment compared to the control. Female Ae. aegypti were significantly more attracted to ovitrap A loaded with the four-component synthetic blend compared to the standard ovitrap in the oviposition bioassays. The compound used in ovitrap A retained its attractant property for up to three days. The chemically-based baited ovitrap may be considered as an option to be integrated during the monitoring of dengue virus vectors in México., (© 2013 The Society for Vector Ecology.)

We collected mosquito immatures from artificial containers during 2010-2011 from 26 communities, ranging in size from small rural communities to large urban centers, located in different parts of Yucatán State in southeastern México. The arbovirus vector Aedes (Stegomyia) aegypti was collected from all 26 examined communities, and nine of the communities also yielded another container-inhabiting Aedes mosquito: Aedes (Howardina) cozumelensis. The communities from which Ae. cozumelensis were collected were all small rural communities (<6,000 inhabitants) in the north-central part of Yucatán State. These new collection records for Ae. cozumelensis demonstrate that this mosquito has a far broader geographic range in the Yucatán Peninsula than previously known. Ae. cozumelensis immatures were collected from both residential premises and cemeteries, with specimens recovered from rock holes as well as various artificial containers including metal cans, flower vases, buckets, tires, and a water storage tank. The co-occurrence with Ae. aegypti in small rural communities poses intriguing questions regarding linkages between these mosquitoes, including the potential for direct competition for larval development sites. Additional studies are needed to determine how commonly Ae. cozumelensis feeds on human blood and whether it is naturally infected with arboviruses or other pathogens of medical or veterinary importance. We also summarize the published records for Ae. cozumelensis, which are restricted to collections from México's Yucatán Peninsula and Belize, and uniformly represent geographic locations where Ae. aegypti can be expected to occur., (© 2012 The Society for Vector Ecology.)