Molecular Evidence of Ehrlichia canis (Rickettsiales: Anaplasmataceae) in Ticks (Ixodida: Ixodidae) Associated with Dogs (Carnivora: Canidae) from Nuevo Leon, Mexico.

Background: Ehrlichia canis is transmitted by ticks causing Canine monocytic ehrlichiosis, which is considered one of the most critical tickborne pathogens. Materials and Methods: This study aimed to identify by PCR technique E. canis in ticks associated with dogs from urban and rural homes in Nuevo Leon, Mexico. The study was conducted at 13 localities in eight municipalities from 2012 to 2021. Results: A total of 1873 ticks of three species were captured: Amblyomma tenellum, Dermacentor variabilis, and Rhipicephalus sanguineus s.l. The overall infection rate of E. canis in ticks was 59.12% (149/252). Of the 15 sequences, three haplotypes were identified. Conclusion: The urban transmission cycle of canine ehrlichiosis is demonstrated, where the potential vector is the tick R. sanguineus s.l.

Molecular and Serological Identification of Anaplasma marginale and Borrelia burgdorferi in Cattle and Ticks from Nuevo Leon, Northern Mexico.

Ticks and tick-borne diseases affect livestock productivity and cause significant economic losses. Therefore, surveillance of these pathogens and vectors is paramount to reducing these effects in livestock. This study aimed to identify Anaplasma marginale and Borrelia burgdorferi sensu lato in ticks collected from cattle. Molecular biology techniques were utilized to identify A. marginale for both types of samples, i.e., ticks and bovine blood. Serology of cattle using indirect immunofluorescence assay (IFA) was conducted to determine antibodies to B. burgdorferi s.l. from seven locations in Nuevo Leon, Mexico, between 2015 and 2017. From 404 bovines, 2880 ticks were collected: Rhipicephalus microplus (2391 females and 395 males), Amblyomma spp. (51 females and 42 males) and Dermacentor variabilis (1 female). Rhipicephalus microplus represented the largest specimens captured, with 96.7% within the seven study sites. PCR processed only 15% (442) of tick samples to identify A. marginale. Field genera proportions were followed to select testing tick numbers. Results showed that 9.9% (44/442) of A. maginale infected the pooled tick species, whereas the highest percent corresponded to 9.4% (38/404) in R. microplus. Regarding the molecular analysis of blood samples, 214 of 337 (63.5%) were positive for A. maginale. In each of the seven locations, at least one bovine sample tested positive for A. maginale. Borrelia burgdorferi s.l. was not found either in the ticks or serum samples. Two A.marginale DNA nucleotide sequences obtained in this study were deposited in the GenBank with the following accession numbers OR050501 cattle, and OR050500 R.microplus tick. Results of this work point to current distribution of bovine anaplasmosis in northern Mexico.

Molecular and Antimicrobial Susceptibility Characterization of Escherichia coli Isolates from Bovine Slaughterhouse Process.

Antimicrobials are routinely used in human and veterinary medicine. With repeated exposure, antimicrobials promote antibiotic resistance, which poses a threat to public health. In this study, we aimed to determine the susceptibility patterns, virulence factors, and phylogroups of E. coli isolates during the killing process in a bovine slaughterhouse. We analyzed 336 samples (from water, surfaces, carcasses, and feces), and 83.3% (280/336) were positive for E. coli. The most common phenotypic resistances that we detected were 50.7% (142/280) for tetracycline, 44.2% (124/280) for cephalothin, 34.6% (97/280) for streptomycin, and 36.7% (103/280) for ampicillin. A total of 82.4% of the isolates had resistance for at least one antimicrobial, and 37.5% presented multiresistance. We detected a total of 69 different phenotypic resistance patterns. We detected six other resistance-related genes, the most prevalent being tetA (22.5%) and strB (15.7%). The prevalence values of the virulence genes were 5.4% in hlyA, 1.4% in stx1, and 0.7% in stx2. The frequencies of the pathogenic strains (B2 and D) were 32.8% (92/280) and 67.1% (188/280) as commensals A and B1, respectively. E. coli isolates with pathogenic potential and multiresistance may represent an important source of dissemination and a risk to consumers.

Research on Integrated Management for Cattle Fever Ticks and Bovine Babesiosis in the United States and Mexico: Current Status and Opportunities for Binational Coordination.

Bovine babesiosis is a reportable transboundary animal disease caused by Babesia bovis and Babesiabigemina in the Americas where these apicomplexan protozoa are transmitted by the invasive cattle fever ticks Rhipicephalus (Boophilus) microplus and Rhipicephalus(Boophilus) annulatus. In countries like Mexico where cattle fever ticks remain endemic, bovine babesiosis is detrimental to cattle health and results in a significant economic cost to the livestock industry. These cattle disease vectors continue to threaten the U.S. cattle industry despite their elimination through efforts of the Cattle Fever Tick Eradication Program. Mexico and the U.S. share a common interest in managing cattle fever ticks through their economically important binational cattle trade. Here, we report the outcomes of a meeting where stakeholders from Mexico and the U.S. representing the livestock and pharmaceutical industry, regulatory agencies, and research institutions gathered to discuss research and knowledge gaps requiring attention to advance progressive management strategies for bovine babesiosis and cattle fever ticks. Research recommendations and other actionable activities reflect commitment among meeting participants to seize opportunities for collaborative efforts. Addressing these research gaps is expected to yield scientific knowledge benefitting the interdependent livestock industries of Mexico and the U.S. through its translation into enhanced biosecurity against the economic and animal health impacts of bovine babesiosis and cattle fever ticks.

Molecular Detection of Leptospira interrogans and Borrelia burgdorferi in Wild Rodents from Mexico.

Leptospirosis and Lyme borreliosis are zoonotic emerging diseases of global importance and wide distribution. The aim of this study was to detect by molecular testing to Leptospira interrogans and Borrelia burgdorferi sensu lato in wild rodents from Nuevo Leon, Quintana Roo, and Campeche, Mexico. This study is the first in report to Chaetodipus nelsoni, Dipodomys merriami, and Peromyscus eremicus infected with L. interrogans in Mexico. Besides, Chaetodipus hispidus, Heteromys gaumeri, Heteromys irroratus, Neotoma micropus, Peromyscus leucopus, Peromyscus maniculatus, and Sigmodon hispidus infected with B. burgdorferi s.l. in Mexico. Also, is the first report in identify coinfection of L. interrogans and B. burgdorferi s.l. in wild rodents such as H. irroratus and S. hispidus in Nuevo Leon, and H. gaumeri in Quintana Roo, Mexico. These wild rodent species infected represent a risk factor for the exposed population in these sylvatic and rural areas of Mexico.

Transport and removal of coliphage PRD1 in constructed wetlands.

The Convection Dispersion Equation (CDE) was used to calculate PRD1 and Br(-) transport parameters in a subsurface flow constructed wetland. Transport parameters from Br(-) displacement were applied into the CDE to estimate a 0.96 day(-1) first order decay coefficient (k). The PRD1 breakthrough curves were also simulated to obtain effective cross-sectional area (Ac), longitudinal dispersion coefficient (D), convective velocity (v), and k. There was practically no difference between Ac and D for both tracers. However, the estimated convective velocity was higher for PRD1 than for Br(-). Further simulations were conducted by taking experimental concentrations from prior research on surface and subsurface flow constructed wetlands. Dispersion number (d) was estimated to be between 0.17 and 0.029 by using PRD1 and Br(-) transport parameters. These parameters were also used to calculate wetland dimensionless removal (K). An analytical solution for the zero moment of the observed breakthrough curves was applied to estimate PRD1 fraction recoveries in the wetland by using d and K. The results of the present study suggest that this analytical solution may be an alternative design tool for pathogen removal estimation in subsurface flow constructed wetlands.

Localización de Serratia marcescens en perfil bacteriológico y fúngico de la conjuntiva de caballos clínicamente sanos en Monterrey, Nuevo León, México / Localization of Serratia marcescens in bacterial and fungal profile of conjunctiva of clinically healthy horses from Monterrey, Nuevo Leon, Mexico

The conjunctival normal microflora, formed by fungi, yeast and bacteria, of 50 clinically healthy horses from Monterrey, Nuevo Leon, was identified using three to 12 year-old horses of different breeds and gender. Samples were taken from the conjunctival sac of both eyes (n =100 eyes) using a cotton swab under sterile conditions. No eye was negative to the presence of the microorganism. There were differences in colony types in each eye of the same animal. One hundred percent were positive to fungal and bacteria colonies in both eyes, while 60% were positive to yeast. In the present study Serratia marcescens, a pathogenic, opportunist and multidrug-resistant organism, is reported for the first time in the conjunctival sac in horses. Serratia marcescens was isolated from 21 clinically healthy horses (42%) with a number of colony forming units (cfu) that ranged from 9 to 42.

Se identificó la microflora normal, formada por hongos, levaduras y bacterias, de la conjuntiva en 50 caballos clínicamente sanos, de diferente raza y sexo, de tres a 12 años de edad, del área metropolitana de Monterrey, Nuevo León. Las muestras se tomaron del saco conjuntival de ambos ojos (n = 100 ojos) con un hisopo bajo condiciones estériles. Ningún ojo fue negativo a la presencia de microorganismos. Hubo a menudo diferencias en los tipos de colonias entre los ojos del mismo animal, 100% fueron positivos a la presencia de hongos y bacterias en ambos ojos, y 60% positivos a la presencia de levaduras. Este estudio presenta, por vez primera en conjuntiva de caballos, la presencia de Serratia marcescens, considerada microorganismo patógeno oportunista con multirresistencia a fármacos. En esta investigación, Serratia marcescens se logró aislar de 21 caballos clínicamente sanos (42%) con rango de nueve a 42 unidades formadoras de colonias (ufc).

Demostración inmunohistoquímica de Mycoplasma bovis en lesiones neumónicas crónicas en ganado en corral de engorda / Immunohistochemical demonstration of Mycoplasma bovis in chronic lung lesions in feedlot cattle

Bovine feedlots are intensive production systems of significant importance in México, United States of America and Canadá. Respiratory diseases are the single most important cause of morbidity and mortality in feedlot cattle. Herein, the gross and microscopic findings in the lungs of cattle with unusually persistent pneumonia unresponsive to aggressive antibiotic treatment in feedlots localized in General Escobedo, Nuevo Leon; Morelia, Michoacan; Mexicali, Baja California, and Culiacan, Sinaloa, Mexico are described. Eight chronic suppurative bronchopneumonia cases with multifocal areas of casseous necrosis were selected. Microscopically, these lesions were bronchocentric and characterized by foci of necrosis surrounded by a pyogranulomatous reaction. Immunohistochemical studies revealed positive reaction to Mycoplasma bovis in all cases. Gross and microscopic lesions associated with M. bovis pneumonia have a conspicuous pattern. This is the first report of M. bovis causing pneumonia in feedlot cattle in Mexico.

El corral de engorda es un sistema de producción intensivo de gran importancia en la ganadería de carne en México, Canadá y Estados Unidos de América. Estudios epidemiológicos indican que las enfermedades respiratorias de los bovinos son el principal problema en corrales de engorda. En este trabajo se describen las lesiones macroscópicas y microscópicas en pulmones de ganado de carne con severa neumonía crónica, a pesar de haber recibido tratamiento con antibióticos en más de tres ocasiones. Se realizaron estudios post mortem de ganado en corrales de engorda localizados en General Escobedo, Nuevo León; Morelia, Michoacán; Mexicali, Baja California y Culiacán, Sinaloa, todos en México. Se seleccionaron ocho casos crónicos de bronconeumonía supurativa con múltiples focos nodulares de exudado necrótico-caseoso. Estos focos necróticos estaban microscópicamente centrados en bronquios y bronquiolos y sus bordes estaban claramente limitados por una reacción piogranulomatosa. Los estudios de inmunohistoquímica demostraron positividad a Mycoplasma bovis en todos los casos. Las lesiones neumónicas macro y microscópicas asociadas con M. bovis tienen un patrón conspicuo. Este es el primer informe de M. bovis en neumonías en ganado de corral de engorda en México.