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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.

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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.

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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.

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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.

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Resumen Introducción: La distribución espacial y temporal de la infección por SARS-CoV-2 sobrepasa las áreas endémicas de enfermedades transmitidas por vector (ETV), cuya vigilancia en México ha cambiado sustancialmente a partir del primer caso confirmado de COVID-19. Objetivos: Estimar y comparar las tasas de incidencia de las ETV antes y después de la introducción del SARS-CoV-2 en México. Métodos: Estudio retrospectivo de casos de ETV de 2014 a 2021. Las tasas de incidencia de cada ETV en el periodo previo (2014-2019) y posterior (2020-2021) a la introducción del SARS-CoV-2 en México fueron calculadas y comparadas. Resultados: Antes de la introducción del SARS-CoV-2, las tasas de incidencia de las ETV fueron altas y posterior a la introducción del coronavirus hubo un descenso en los índices epidemiológicos; sin embargo, solo se identificó diferencia estadística significativa en la tasa de incidencia de la malaria (p ≤ 0.05) y otras rickettsias (p ≤ 0.05). Conclusiones: Algunas medidas para reducir los casos de COVID-19, como el distanciamiento social, el confinamiento domiciliario, la reducción en el aforo en el transporte público y el trabajo en casa, probablemente contribuyeron a disminuir temporalmente el número de casos de las ETV; sin embargo, puede haber rebrote de las ETV en el futuro cercano.

Abstract 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.

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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.

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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.

INTRODUCCIÓN: La distribución espacial y temporal de la infección por SARS-CoV-2 sobrepasa las áreas endémicas de enfermedades transmitidas por vector (ETV), cuya vigilancia en México ha cambiado sustancialmente a partir del primer caso confirmado de COVID-19. OBJETIVOS: Estimar y comparar las tasas de incidencia de las ETV antes y después de la introducción del SARS-CoV-2 en México. MÉTODOS: Estudio retrospectivo de casos de ETV de 2014 a 2021. Las tasas de incidencia de cada ETV en el periodo previo (2014-2019) y posterior (2020-2021) a la introducción del SARS-CoV-2 en México fueron calculadas y comparadas. RESULTADOS: Antes de la introducción del SARS-CoV-2, las tasas de incidencia de las ETV fueron altas y posterior a la introducción del coronavirus hubo un descenso en los índices epidemiológicos; sin embargo, solo se identificó diferencia estadística significativa en la tasa de incidencia de la malaria (p ≤ 0.05) y otras rickettsias (p ≤ 0.05). CONCLUSIONES: Algunas medidas para reducir los casos de COVID-19, como el distanciamiento social, el confinamiento domiciliario, la reducción en el aforo en el transporte público y el trabajo en casa, probablemente contribuyeron a disminuir temporalmente el número de casos de las ETV; sin embargo, puede haber rebrote de las ETV en el futuro cercano.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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) × 1012 /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) × 109 /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.

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