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.

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.

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.

As part of our routine surveillance for arboviruses transmitted by Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) in Yucatán State, México, we regularly monitor the mosquito fauna that occurs in the region. In this study, immature and adult mosquitoes were collected at 60 study sites (including residential premises, churches, tourist areas, cemeteries, forested areas, and garbage dump sites) in Yucatán State from Jul 2014 to Dec 2015. In total, 4,062 larvae, 344 pupae, and 3,812 adults representing 7 genera and 27 species were collected. Three species had never before been identified in Yucatán State, and these are Aedes (Ochlerotatus) euplocamus Dyar & Knab, Aedes (Protomacleaya) podographicus Dyar & Knab, and Culex (Culex) declarator Dyar & Knab. The identification of these 3 species brings the current total of mosquito species recognized in Yucatán State to 52 (with 11 genera). Many of the mosquitoes collected in this study were temporally and spatially associated with Ae. aegypti. Resumen Como parte de la vigilancia de arbovirus transmitidos por Aedes (Stegomyia) aegypti L., en el estado de Yucatán, México; regularmente monitoreamos la fauna de mosquitos presentes en la región. En este estudio, los estadios de inmaduras y adultos de mosquitos fueron colectados en 60 localidades en el estado de Yucatán durante julio de 2014 y diciembre de 2015. Un rango amplio de lugares urbanos y rurales fueron examinados, incluyendo casas, iglesias, áreas turísticas, cementerios, selva y un basurero municipal. Un total de 4,062 larvas, 344 pupas y 3,812 adultos fueron colectados, representando siete géneros y 27 especies. Tres especies fueron identificadas como nuevas para la fauna de mosquitos de Yucatán: Aedes (Ochlerotatus) euplocamus Dyar and Knab, Aedes (Protomacleaya) podographicus Dyar and Knab y Culex (Culex) declarator Dyar and Knab. Adicionando estas tres especies, actualmente hay 52 especies (con 11 géneros) de mosquitos en Yucatán. Muchos de los mosquitos colectados en el presente estu...

The aim of this study was to assess the biodiversity of mosquito species in houses of the five ecological regions and update the checklist of species previously reported in the state of Tabasco. In total, 325 dwellings at 43 localities in the five ecological regions were sampled. Collection was by entomological CDC backpack aspirator. The mosquitoes captured were identified using published taxonomic keys and the aid of a stereomicroscope. In total, 4,622 mosquitoes of 15 species in 10 genera were captured. Two species not previously reported in Tabasco State were found: Aedes (Ochlerotatus) angustivittatus (Dyar and Knab, 1907) and Mansonia dyari Belkin, Heinemann & Page, 1970. The mosquito fauna of the state of Tabasco, including the new species are 55 species in 17 genera. Most species found transmit diseases to humans and should be included in government mosquito control programs.

: 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.