Gilberto Lopez Valencia

Autonomous University of Baja California | UABC · Institute for Research in Veterinary Science

During a 3000 kms-exploratory fieldtrip along the peninsula of Baja California, Mexico, we used mice-baited traps in search of Triatominae. Specimens of Paratriatoma hirsuta and Dipetalogaster maxima w ere collected.

The objective of this study was to assess the presence of genotype 2 porcine reproductive and respiratory syndrome virus (PRRSV-2) in Baja California (Baja), as well as the standardization of the qRT-PCR technique. A cross-sectional study was conducted from 2016 to 2017 in farms from Baja. It was obtained 97 blood samples from clinically healthy, n...

Los ovinos son una especie explotada en diferentes ámbitos de la producción. Estos son propensos a diferentes patógenos, destacando parásitos como Haemonchus contortus. El clima predominante y las prácticas de manejo en la crianza se consideran los principales factores que impulsan la distribución espacial y temporal del nematodo. Su distribución e...

The Mexican territory of the Yucatan Peninsula has a tropical climate and harbors a wide variety of domestic, synanthropic, and wild animals, as well as disease vectors. To determine the distribution of recorded zoonotic diseases in the Yucatan Peninsula, scientific publications referring to these diseases in animals and containing geographic coord...

Eighty Holstein calves born in a dairy farm with good management practices were used to evaluate the effect of treatments on calf-starter intake, growth rate, and incidence of gastrointestinal disorders during first 30 days of birth. Calves were fed (4L during first 6-h of birth) with unheated (RAW) or pasteurized (PST, pasteurized during 60 min at...

Las técnicas de diagnóstico por imagen son métodos no invasivos o mínimamente invasivos que permiten la visualización de órganos internos y el estudio de su función. Incluyen la ecografía, radiología, tomografía computarizada, resonancia magnética y medicina nuclear, entre otras. El diagnóstico por imagen se ha convertido en un componente esencial...

El complejo respiratorio bovino (CRB) es la principal causa de enfermedad y muerte en el ganado de engorda en todo el mundo. Es un síndrome infeccioso multifactorial provocado por distintos virus y bacterias que disminuyen la eficiencia productiva y ocasionan pérdidas económicas. En México, el CRB se ha reportado en todas las regiones donde se engo...

Stray dogs are one of the main reservoirs of intestinal parasitic infections and some have zoonotic potential. The epidemiological survey was carried out between September 2017 and May 2018 in Mexicali Valley, this area sacrifices around 92,470 head of cattle monthly, which represents 27% of the national slaughter and has 71,307 hectares for crops....

La comunidad de Ojos Negros está ubicada en el municipio de Ensenada Baja California, México. Desde 1930, los residentes locales fabrican un queso artesanal muy apreciado en la región; sin embargo, la leche cruda y el queso nunca han sido analizados por la calidad microbiológica y de higiene del producto final. El objetivo del presente estudio fue...

In many rural regions of Mexico, beekeeping is an important socioeconomic activity which is currently facing various health issues, being the main one the presence of infectious diseases. The aim of our study was to optimize a duplex Eva Green RT-PCR assay along with melting-curve analysis to detect and differentiate Nosema apis from Nosema ceranae...

The aim of this study was to detect the presence of porcine circovirus type 2 (CVP2) in pig herds of Baja California, Mexico, using the polymerase chain reaction (PCR) technique. Blood samples (n=97) were collected from 97 pigs in 26 farms. The DNA was extracted from the buffy coat and the samples were grouped into 19 groups of five samples and one...

Objectives: This study was conducted to examine the effect of urea fermentation potential (UFP) on digestive function, BUN, growth performance, and dietary energetics, in steers fed a finishing diet based on steam-flaked corn containing 15% dried distillers grains with solubles. Materials and Methods: Four UFP levels were evaluated (−0.30, 0.10, 0....

An epidemic of Rocky Mountain spotted fever (RMSF) is ongoing in Mexicali, México. We visited 100 neighborhoods with diagnosed human cases and 100 control neighborhoods to evaluate knowledge of the epidemic; obtain data on the spatial distribution of dogs, canine seroprevalence and active infection, tick infestations, and presence of rickettsial DN...

La tuberculosis (tb) en humanos y en animales sigue siendo uno de los problemas de salud más importantes a escala mundial. La tb bovina (tbb) afecta a la población humana mediante el contacto con animales enfermos, consumo de leche y sus derivados sin pasteurizar. Diversos estudios señalan que una gran cantidad de casos de tb en humanos es provocad...

Salmonellosis has a worldwide relevance in aspects associated with public health, as only in 2009 were reported 93.8 million cases in humans. The objective of the study was to establish the prevalence, risk factors and bacteriological and molecular identification of Salmonella spp in stray dogs in urban, rural and coastal areas of Mexicali, a city...

Bovine mastitis is a disease of high economic impact for the dairy industry and some of the etiological agents that cause it are also of interest in the field of public health. The purpose of study was to identify the bacterial causes of bovine mastitis from seven dairy farms located in the Baja California Peninsula. A total of 316 milk samples wer...

La mastitis bovina es una enfermedad de alto impacto económico para la industria lechera, y algunos de los agentes etiológicos que la provocan también son de interés en el ámbito de salud pública. El objetivo de este estudio fue identificar las especies bacterianas aisladas de casos de mastitis bovina, provenientes de siete establos lecheros ubicad...

Leptospira infects a wide range of companion, domestic and wild animal species, shedding the spirochetes into the environment via urine. Dogs become infected by direct or indirect contact with wild or domestic infected animal reservoirs increasing the risk of zoonotic transmission of the disease. The microscopic agglutination test has been used as...

Objectives: To determine genetic diversity by comparing the whole genome sequences of M. bovis cattle and human isolates from Baja California. Methods: We used a whole genome sequencing strategy to obtain the molecular fingerprints of 172 isolates of Mycobacterium bovis from Baja California, Mexico, of which 155 were isolated from cattle, and 17...

In the present study the effect of antimicrobial peptide K9CATH was evaluated in a murine model of mastitis by Staphylococcus aureus. Mastitis was induced with a clinical isolate of S. aureus in 20 female Balb/c mice at 7 to 10 days of lactation. Ten mice (treatment group) received daily intramammary infusions of 32 μg/50 μL K9CATH peptide, for 3 c...

Bovine tuberculosis (TBB) is a zoonotic disease distributed worldwide and is of great importance for public health and the livestock industry. Several experimental vaccines against this disease have been evaluated in recent years, yielding varying results. An example is the Bacillus Calmette-Guérin (BCG) vaccine, which has been used extensively in...

Zoonotic parasitic infections are a major global public and veterinary health problem and widespread among stray dogs. The objective of this study was to establish the prevalence of intestinal parasites in stray dogs in the urban, rural and coastal areas of Mexicali County in northwest Mexico. In 2014, from January to December, 380 stray dogs were...

Bovine respiratory disease (BRD) is the main reason for economic loss in feedlots. A cross-sectional study was conducted in order to detect the pathogens involved in BRD. A total of 88 animals with respiratory signs were sampled for diagnosis using PCR. The detected pathogens were bovine respiratory syncytial virus (80.6%), Mannheimia haemolytica (...

Thirty Holstein calves presenting infectious diarrhea during the second week following birth were utilized to evaluate the effects of a standardized product containing a combination of probiotics, ß-glucans and glyconutrients (GLY) in support of antibiotic therapy during the early rearing phase (d 7 to d 45 following birth). Treatments were 1) anti...

Paratuberculosis (PTB) or Johne’s disease is a common ruminant infectious disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). In this study, two MAP antigens were compared for their diagnostic utility to detect subclinical PTB in a sheep flock in Mexicali, Mexico. Sheep (n = 31) without clinical signs but positive on a direct fecal...

Twenty-one Holstein bull calves (368 ± 5.2 kg) were used in order to evaluate the effects of combining recombinant bovine growth hormone (bST) and anabolic implants on growth performance and dietary energetics. Steers were assigned (7 repetitions/ treatment) to individual pens (16 m2) equipped with automatic waterers and 1.2 m fence-line feed bunks...

Growth-finishing programs for Holstein calves in feedlots have become popular recently in Northwest Mexico. Holstein steers respond with greater gains to high-grain diets than beef steers and are more tolerant to heat stress (1); however, Holsteins require 10% to 12% more energy for maintenance than beef breeds, and they have less muscling than bee...

The prevalence of bovine cysticercosis was established using routine postmortem inspection of 52,322 feedlot cattle slaughtered at 1 Federal Inspection Type abattoir (TIF 301) located in the Mexicali Valley in Baja California, México. The study included 31,393 animals (60.0%) purchased and transported to Baja California from stocker operations loca...

Rickettsiosis caused by Rickettsia rickettsii is capable of infecting vertebrates, including humans. The symptoms are high fever, headache, myalgia, nausea, vomiting, abdominal pain, and cough. Mortality can be up to 30% in untreated patients. To prove the existence of rickettsiosis in Ensenada, Baja California, Mexico, because no human cases have...

Rabies is a fatal infection of the central nervous system produced by a Lyssavirus of the family Rhabdoviridae. The virus is distributed worldwide and is primarily transmitted by rabid animal bites, with multiple reservoirs depending on the region. The vampire bat Desmodus rotundus is distributed in several states of Mexico and is considered the ma...

Este es el primer reporte sobre aislamiento y tipificación molecular de Mycobacterium avium subespecie paratuberculosis (Map) en ganado bovino y ovino en Mexicali-Baja California; región con antecedentes serológicos de paratuberculosis en pequeños rumiantes. Se analizaron cinco muestras de ovinos y uno de bovino provenientes de animales que present...

The present study is the first report of the isolation and molecular typing of Mycobacterium avium subspecies paratuberculosis (Map) in cattle and sheep in Mexicali-Baja California; region with serological history of paratuberculosis in small ruminants. In this study, 5 blood samples of sheep and 1 from cattle showing signs sugestive of paratubercu...

A commercially available multi-antigen lateral flow assay (LFA) for detection of antibodies to Mycobacterium bovis was evaluated by testing dairy cattle in Baja California, México. Sera and tissue samples were obtained from 268 dairy cattle at a slaughterhouse and were tested by LFA, bacteriological culture, and polymerase chain reaction (PCR). Of...

In Mexico, bovine tuberculosis (TB) is one of the main problems which face the national livestock sector. Currently, there are molecular methods for the detection and genotyping of bovine TB, making it possible to determine the relationship between the different strains present in the region and identify some factors influencing the control and era...

In Mexico, bovine tuberculosis (TB) is one of the main problems which face the national livestock sector. Currently, there are molecular methods for the detection and genotyping of bovine TB, making it possible to determine the relationship between the different strains present in the region and identify some factors influencing the control and era...

Four Holstein steers were used in a 4 x 4 Latin square experiment to evaluate the potential benefits of the surfactant Tween 80 on intestinally fatty acids digestion. Tween 80 was infused continuously into the abomasu at rates of 0, 2.5, 5.0 and 7.5 mL/kg of a basal diet containing 93 g lipid/kg (DM basis). There were no treatment effects (P > 0.05...

About 553 Dairy cattle carcasses were inspected at a slaughter house in Baja California, out of 298 showed gross tuberculosis-like lesions. Microscopic examination of tissues using H and E and acid fast staining revealed 268 suspect cases. Of the 268, 104 were culture positive while 123 were PCR positive for M. tuberculosis complex. A total of 70 s...

The protective efficacy of Mycobacterium bovis BCG (1 × 106 single dose) was evaluated under field conditions. A total of 140 male Holstein Friesian calves, one to two week-old were selected. Two groups of 70 each were formed, one group was vaccinated and the other was injected with a placebo during their second week of age and followed until 12 mo...

An epidemiological field study was performed on a commercial dairy herd with a 40% prevalence of tuberculosis (on their 1st year of age and 45 days after first partum), in order to evaluate in two stages the Mycobacterium bovis-Bacillus Calmette-Guerin (Mb-BCG) vaccine. For this study, a total of 130 calves (2 weeks or younger), which tested negati...

Lyme borreliosis, a worldwide zoonotic disease and characterized by polisystemic disorders, is caused by the spirochete B. burgdorferi, which is transmitted by a tick bite, primarily from Ixodes scapularis and I. pacificus. In Mexico, native Lyme disease has been recently reported in humans, while canine B. burgdorferi infection has been also repor...

Background: West Nile virus (WNV) is an important public health flavivirus transmitted to humans by infected mosquitoes. Transmission involves birds and primarily Culex sp. mosquitoes, with humans as incidental hosts but with severe disease in some cases. Methods: A total of 2,333 mosquitoes distributed in 92 pools were sampled in a locality of Mex...

This study was performed to estimate the seroprevalence of larva migrans of Toxocara canis and identify associated risk factors among children in Mexicali, Mexico. Blood samples (n=288) were collected randomly from children examined at the IMSS Clinical Laboratory and serum was tested by ELISA. The adjusted seroprevalence of toxocarosis was 10.6% (...

A cross-seccional study was carried out in order to estimate the seroprevalence of antibodies against Ehrlichia canis as well as track patients suspected of carrying the disease. A total of 384 blood samples obtained from canine patients of 38 veterinary clinics in the urban area of Mexicali, Baja California, Mexico were randomly collected during 2...

The aim of this pilot study was to estimate the seroprevalence to Borrelia burgdorferi in dogs from a Mexico-U.S. border region. A total of 94 dogs were tested by Borrelia burgdorferi ELISA kit. Borreliosis or Lyme desease is a worldwide zoonotic tick-borne disease caused by the espirochete Borrelia burgdorferi This disease is characterized by arth...

We conducted a cross-sectional study to estimate the seroprevalence to larva migrans of Toxocara canis in dogs of the urban area of Mexicali Baja California, México, for a 12 month period, from dogs attended at private veterinary clinics. Also, the risk factors associated with the seropositive values were evaluated. Sera were tested for antibodies...

The aim of the present study was to determine the frequency of Toxocara canis eggs in public parks in the city of Mexicali, B.C., Mexico. A total of 32 parks were sampled and examined using the zinc sulphate flotation method. Association between the frequency of T. canis eggs and the socioeconomic status and level of education of neighborhoods wher...

A pilot study was conducted to estimate the seroprevalence to Ehrlichia canis in dogs in a Mexico-U.S. border desert region. A total of 94 dogs were tested by Ehrlichia canis ELISA kit. Information of dogs regarding gender, age, size and intensity of tick infestation was collected and the significance of these class variables was determined by Chi-...

In order to determine the frequency and distribution of lesions and/or diseases associated with lameness problems in commercial dairy herds with Holstein cows, in Baja California, Mexico, a two stage transverse epidemiological study was carried out in 592 milking cows with frequent lameness. During the first stage, a locomotion scoring method (LS),...

A study to evaluate the accuracy of pregnancy diagnosis in dairy cows was conducted using animals between 20 and 40 days after service. The accuracy of the method was obtained calculating the sensitivity, specificity, positive and negative predictive values (PPV and NPV). The highest values in these indicators were obtain between 31-35 and 36-40 da...

To implement a disease monitoring system in federal, municipal, and private abattoirs in Baja California, Mexico and to estimate annual prevalence of tuberculosis (TB) in beef and dairy cattle slaughtered and inspected in 1995 and 1996. Epidemiologic survey. About 200,000 cattle (95% beef, 5% dairy). Lymph node and tissue specimens with lesions sug...