Increasing Public Health Mosquito Surveillance in Hidalgo County, Texas to Monitor Vector and Arboviral Presence

From 2016 to 2018, Hidalgo County observed the emergence of Zika virus (ZIKV) infections along with sporadic cases of Dengue virus (DENV) and West Nile virus (WNV). Due to the emergence of ZIKV and the historical presence of other mosquito-borne illnesses, Hidalgo County obtained funding to enhance mosquito surveillance and educate residents on arboviruses and travel risks. During this time period, Hidalgo County mosquito surveillance efforts increased by 1.275%. This increase resulted in >8000 mosquitoes collected, and 28 mosquito species identified. Aedes aegypti, Ae albopictus and Culex quinquefasciatus made up approximately two-thirds of the mosquitoes collected in 2018 (4122/6171). Spatiotemporal shifts in vector species composition were observed as the collection period progressed. Significantly, temperature variations (p < 0.05) accounted for associated variations in vector abundance, whereas all other climate variables were not significant.

Autochthonous, zoonotic Onchocerca lupi in a South Texas dog, United States

Background Onchocerca lupi is an emerging, zoonotic filarioid nematode associated with ocular disease in companion animals in North America and the Old World. The areas where this parasite is assumed to be endemic in the USA comprise southwestern states. Thus far, all cases reported outside of the southwest are associated with travel or animal movement. Methods An 11-year-old, castrated male Pitbull dog from McAllen, Hidalgo County, southern Texas, with no travel history, was diagnosed with a perforating corneal ulceration of the right eye. Enucleation was performed and tissues submitted for histopathology. Results Histologically, sections of two filarioid nematodes were observed. DNA was extracted from formalin-fixed paraffin-embedded tissue using a commercial kit. We performed PCR targeting the cox1 gene of the mitochondrial DNA, followed by sequencing and phylogenetic analysis. Altogether, these results confirmed the identification of the nematode specimens as O. lupi, phylogenetically belonging to haplotype 1. Conclusion We report the first autochthonous case of O. lupi in a dog from Hidalgo County, southern Texas, USA. Our finding suggests Texas as an additional state where this zoonotic nematode is endemic. Further investigations are required to understand the epidemiology of this parasite along the USA/Mexico border. Graphic abstract

First report of squash vein yellowing virus naturally infecting butternut squash (Cucurbita moschata) in Texas

Virus diseases are major constraints to the production of cucurbits in the Texas Lower Rio Grande Valley. In September 2020, a ~8.1 ha butternut squash (Cucurbita moschata) field in Hidalgo County, Texas, was observed with virus-like symptoms of vein yellowing, leaf curl, mosaic, and foliar chlorosis. The proportion of plants with virus-like symptoms in this field was estimated at 30% and seven samples (symptomatic = 5; non-symptomatic = 2) were collected randomly for virus diagnosis. Initially, equimolar mixtures of total nucleic acid extracts (Dellaporta et. al. 1983) from two symptomatic samples from this field and extracts from 12 additional symptomatic samples from six other fields across south and central Texas was used to generate one composite sample for diagnosis by high throughput sequencing (HTS). The TruSeq Stranded Total RNA with Ribo-Zero Plant Kit (Illumina) was used to construct cDNA library from the composite sample, which was then sequenced on the Illumina NextSeq 500 platform. More than 26 million single-end HTS reads (75 nt each) were obtained and their bioinformatic analyses (Al Rwahnih et al. 2018) revealed several virus-like contigs belonging to different species (data not shown). Among them, 6 contigs that ranged in length from 429 to 3,834 nt shared 96 to 100% identities with isolates of squash vein yellowing virus (SqVYV), genus Ipomovirus, family Potyviridae. To confirm the HTS results, total nucleic acid extracts from the cucurbit samples from all seven fields (n = 46) were used for cDNA synthesis with random hexamers and the PrimeScript 1st strand cDNA Synthesis Kit (Takara Bio). A 1-μL aliquot of cDNA was used in 12.5-μL PCR reaction volumes with PrimeSTAR GXL DNA Polymerase (Takara Bio) and two pairs of SqVYV-specific primers designed based on the HTS derived contigs. The primer pairs SqYVV-v4762: 5′-CTGGATTCTGCTGGAAGATCA & SqYVV-c5512: 5′-CCACCATTAAGGCCATCAAAC and SqYVV-v8478: 5′-TTTCTGGGCAAACAAACATGG & SqYVV-c9715: 5′-TTCAGCGACGTCAAGTGAG targeted ~0.75 kb and ~1.2 kb fragments of the cylindrical inclusion (CI) and the complete coat protein (CP) gene sequences of SqVYV, respectively. The expected DNA band sizes were obtained only from the five symptomatic butternut squash samples from the Hidalgo Co. field. Two amplicons per primer pair from two samples were cloned into pJET1.2/Blunt vector (Life Technologies) and bidirectionally Sanger sequenced, generating 753 nt partial CI specific sequences (MW584341-342) and 1,238 nt that encompassed the complete CP (MW584343-344) of SqVYV. In pairwise comparisons, the partial CI sequences shared 100% nt/aa identity with each other and 98-99% nt/aa identity with corresponding sequences of SqVYV isolate IL (KT721735). The CP cistron of TX isolates shared 100% nt/aa identity with each other and 90-98% nt (97-100% aa) identities with corresponding sequences of several SqVYV isolates in GenBank, with isolates IL (KT721735) and Florida (EU259611) being at the high and low spectrum of nt/aa identity values, respectively. This is the first report of SqVYV in Texas, naturally occurring in butternut squash. SqVYV was first discovered in Florida (Adkins et al. 2007) and subsequently reported from few other states in the U.S. (Adkins et al. 2013; Egel and Adkins 2007; Batuman et al. 2015), Puerto Rico (Acevedo et al. 2013), and locations around the world. The finding shows an expansion of the geographical range of SqVYV and adds to the repertoire of cucurbit-infecting viruses in Texas. Further studies are needed to determine the prevalence of SqVYV in Texas cucurbit fields and an assessment of their genetic diversity.

DIET OF EIGHT SPECIES OF LIZARDS FROM GRANITE GAP, HIDALGO COUNTY, NEW MEXICO

Granite Gap is a desert scrub habitat located in the Chihuahuan Desert in southwestern New Mexico about 200 km from the Texas border. In May 2016, we collected specimens of eight lizard species, six of which range into Texas: Callisaurus draconoides, Cophosaurus texanus, Uta stansburiana, Urosaurus ornatus, Gambelia wislizenii, and Aspidoscelis sonorae (a parthenogenetic species), plus two species not found in Texas: Sceloporus clarkii and Aspidoscelis tigris. We analyzed stomach contents of the preserved lizards and computed diet breadth and overlap for each. All lizard species consumed arthropods only. Considering the entire sample, there was a significant correlation between lizard snout-vent length (SVL) and total volume of arthropods consumed, and between lizard SVL and mean volume per prey item, but not between lizard SVL and number of arthropods consumed. This suggests larger lizards did not consume more arthropods than smaller lizards, but they did consume larger ones. Overall, A. sonorae was the most specialized lizard species at Granite Gap whereas C. texanus seemed to be the most generalized owing to its high numeric and high volumetric diet breadth. The dietary overlap data suggest there were two groups of lizards at Granite Gap: one that consumes a large number and volume of termites (Callisaurus, Cophosaurus, and the two species of Aspidoscelis) and the other that consumes a large number and volume of ants (Uta, Urosaurus, small Sceloporus) plus cicadas when lizard size is large enough to consume them (large Sceloporus and Gambelia).

Detection of a Locally-Acquired Zika Virus Outbreak in Hidalgo County, Texas through Increased Antenatal Testing in a High-Risk Area

Hidalgo County (HC), located along the Texas–Mexico border, was listed as a high-risk county for Zika virus (ZIKV) in 2017 by the Texas Department of State Health Services, based on its historical presence of Dengue. Due to its subtropical climate, active binational travel, and population of low socioeconomic status, Hidalgo County focused on disease detection activities for the prevention of further transmission. Therefore, Hidalgo County Health and Human Services enacted public health surveillance, reviewed laboratory results, and conducted epidemiological investigations from 2016 to 2018. In 2017, Hidalgo County experienced a locally-acquired outbreak of Zika virus disease, resulting in the highest local mosquito-borne acquisition case count for the year within the United States. This resulted in Hidalgo County reviewing epidemiological data for disease detection and risk areas. With the data review, key outcomes of testing were identified. This included the importance of both RT-PCR and IgM-ELISA/PRNT testing methods. In addition, increased antenatal testing and surveillance also recognized the need of improved disease identification and testing among the general population, especially during localized outbreaks.

A Description of the Possible Etiology of the Cilantro Yellow Blotch Disease

A virus-like disease characterized by foliar yellow blotch symptoms and resembling those described for cilantro yellow blotch disease in California was observed in a 4.05-ha cilantro (Coriandrum sativum) cv. Santo field in Hidalgo County, Texas during spring 2019. Disease incidence at harvest was estimated at ∼20%, and the affected plants were rendered unmarketable. Foliar systemic chlorosis symptoms were observed on sap-inoculated Nicotiana occidentalis plants (n = 3) using inocula from symptomatic cilantro. Total RNA aliquots from 11 randomly collected leaf tissue samples (symptomatic = 7, asymptomatic = 4) were pooled into a composite cilantro RNA sample which was analyzed by high throughput sequencing (HTS). Analyses of the obtained 15.7 million raw reads (76 nt each) yielded virus-specific contigs that mapped to the genomes of alfalfa mosaic virus (AMV), beet pseudoyellows virus (BPYV), and lettuce chlorosis virus (LCV). Virus-specific primers designed from the HTS-derived sequences were used to screen the samples in two-step RT-PCR assays, resulting in the detection of AMV+BPYV in 3 of 7 symptomatic cilantro samples, AMV+LCV in 4 of 7 symptomatic cilantro samples, and AMV alone in the 4 asymptomatic cilantro and sap-inoculated N. occidentalis samples. The results represent the first reports of the natural infection of cilantro by BPYV and LCV and implicate the mixed infection of a Crinivirus and AMV in cilantro yellow blotch disease.

A revision of the genus Eurhoptus LeConte, 1876 (Curculionidae, Cryptorhynchinae) of America north of Mexico

The genus Eurhoptus LeConte, 1876 is revised for America north of Mexico. Eight species are recognized including E.pyriformis LeConte, 1876, E.sordidus (LeConte, 1876), E.curtus (Hamilton, 1893), resurrected name, and five new species as follows: E.rileyi new species (type locality, Texas, Hidalgo County, Bentsen Rio Grande State Park), E.imbricatus new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.cariniventris new species (type locality, Texas, Bandera County, Lost Maples State Natural Area), E.occidentalis new species (type locality, Texas, Brewster County, Big Bend National Park), and E.aenigmaticus new species (type locality, Alabama, Winston County, Bankhead National Forest). Descriptions or redescriptions, and images of taxonomically important structures are presented for all species. A key to the eight species is included.