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In addition to the direct issues associated with the parasitic association between ticks and cattle, approximately 20 million heads of cattle are exposed to diseases. The main goals of this study w...

Objectives This study reports the draft genome sequence of Pseudoalteromonas piscicida strain 36Y_RITHPW, a marine Gammaproteobacteria that synthesises bioactive compounds with antagonistic activity against Vibrio parahaemolyticus, a multidrug-resistant strain that is the causative agent of acute hepatopancreatic necrosis disease (AHPND), reported in shrimp farm outbreaks from Asia to Mexico with mortality rates of 80–100%. Methods The genome of P. piscicida 36Y_RITHPW was sequenced with an Ion Torrent™ Personal Genome Machine™ (PGM) platform. A total of 606 805 reads were constructed for a 308.48 Mbp and 33.5 × coverage. A high-quality draft assembly and ordering of contigs was obtained with Mauve. The annotation was obtained with RAST and antiSMASH. Results The genome size consists of 5.15 Mbp, with a total of 4548 genes, 4217 protein-coding sequences and a GC content of 43.3%. Several resistance genes as well as other genes involved in the production of bacteriocins and ribosomally synthesised antibacterial peptides are also present. Conclusions Mining of this draft genome provides valuable information to explain the antagonistic capacity of P. piscicida 36Y_RITHPW, a useful strain as a potential probiotic in shrimp aquaculture against pathogenic V. parahaemolyticus.

Trypanosoma cruzigrowth inhibition by extremely low-frequency electromagnetic fields. Short communication

Rhipicephalus sanguineus sensu lato (s.l.) is the most widespread tick in the world and is a well-recognized vector of many pathogens that affect dogs and, occasionally, humans. There is scarce inf...

Although having five different ways of transmission the vector-borne is the principal way of transmission of Chagas disease, which involves insects of the subfamily Triatominae (Hemiptera: Reduviidae). Nineteen of the 31 species that occur in Mexico are associated with humans, and all are capable of transmitting the disease. Pyrethroids are the insecticides recommended for the control of these vectors in Mexico. We determined the susceptibility to the pyrethroids deltamethrin and permethrin of peridomestic populations of Triatoma mazzottii Usinger and two populations of Triatoma longipennis Usinger in comparison with a reference strain for each species. Bioassays were performed for the determination of the LD50 for both field populations and reference strains. A maximum of 27 fold resistance to deltamethrin was observed in T. mazzottii, meanwhile, for permethrin, T. longipennis from Jalisco show the highest value of 3.19 fold. There was significantly increased activity of esterases in field populations in comparison with their corresponding reference strain. The results of the search of kdr mutations related to the resistance to deltamethrin and permethrin in the evaluated species show the presence of mutations in the field populations, as is the case with individuals of T. mazzottii, for which the mutation was found A943V, and for the two populations of T. longipennis included in this study, we report the presence of the kdr mutation K964R. Evaluation of the various mechanisms involved in resistance to pyrethroids in triatomines from Mexico could guide us to the real justification for insecticide resistance monitoring.

Introducción. En los últimos años, la tripanosomiasis americana se ha convertido en un problema de salud pública emergente en países receptores de poblaciones migrantes, como México, Estados Unidos, Canadá y los países europeos.Objetivo. Analizar la prevalencia de anticuerpos anti-Trypanosoma cruzi mediante técnicas serológicas, en los migrantes latinos en su paso hacia Estados Unidos y Canadá.Materiales y métodos. Se hicieron análisis serológicos mediante ELISA y la prueba de hemaglutinación indirecta (HAI) para detectar anticuerpos anti-T. cruzi, y encuestas socioeconómicas para determinar los factores asociados a los casos seropositivos que favorecieron la transmisión en el país de origen de los migrantes.Resultados. La seroprevalencia total en la población estudiada fue del 20 % (24/120). La prevalencia más alta se encontró en migrantes de Guatemala, con 37,5 % (6/16), seguidos de los de Honduras (22,6 %; 12/53), El Salvador (16 %; 4/25) y México (8,7 %; 3/23). De los 120 migrantes encuestados, 105 (87,5 %) reconocieron el vector y 62 (59 %) afirmaron haber sido picados por este. La asociación de la infección con los materiales de construcción de las paredes de las viviendas, así como con la presencia de mascotas (perros) en los hogares, fue muy significativa (p≤0,01). La asociación con el material de construcción del patio, los servicios básicos precarios, así como la cría de animales dentro de corrales en la periferia de los hogares, también fue significativa (p≤0,05).Conclusión. Los países no endémicos que reciben migrantes de zonas endémicas deben mejorar o desarrollar políticas de salud para prevenir la transmisión del parásito por transfusión o por vía congénita.

Chagas disease, caused by the protozoan Trypanosoma cruzi, is an important public health concern in areas extending from South America northward into the southern United States of America. Although this hemoflagellate has many wild and domestic mammalians reported as reservoir hosts, studies on this subject are scarce in Nuevo Leon state, a region located in northeastern Mexico. This cross-sectional study showed that the general prevalence of T. cruzi infection in Nuevo Leon state was 14.5% (35/241), this percentage matching the ones determined by PCR and traditional diagnostics. Localities and infected mammals did not significantly differ (χ2=6.098, p=0.192); however the number of infected animals was highly correlated with mammalian species (p=0.009). Striped skunks (Mephitis mephitis) were found to be the most infected overall (11/34, 32.3%), while dogs (Canis familiaris) had the lowest prevalence. In conclusion, although the prevalence of T. cruzi infection in small mammals was lower in Nuevo Leon than in other states of Mexico, our results provide new locality records, including striped skunks, opossums (Didelphis marsupialis) and dogs, and extend the recorded area to woodrats (Neotoma micropus).

Chagas disease is caused by an infection with the protozoan hemoflagellate Trypanosoma cruzi, and it is a major endemic health problem in Latin America. The congenital route is one of the main non-vectorial pathways of transmission, which can arise either in the chronic or acute phase of maternal infection. Serological screening of T. cruzi infection was performed in 520 pregnant women and newborns at the Hospital General Regional de Leon, Guanajuato, Mexico, between 2014 and 2015. Anti-T. cruzi antibodies were detected in 20 mothers (4%) by ELISA and HIA with four PCR-positive newborn cases. Risk factors were identified according to an epidemiological survey, and the most significant (P

Largemouth bass,Micropterus salmoides, is a native fish species with special importance for sport fishing competitions in Nuevo León, Mexico. However, no study has investigated the parasitic fauna ofM. salmoides, and no reports are available on monogenean parasites in this fish species. Therefore, we described the monogenean parasites ofM. salmoidesand the effects of season and fish condition factor in five reservoirs: La Boca (LB), El Cuchillo–Solidaridad (CS), Sombreretillo (S), Laguna Salinillas (LS) and Cerro Prieto (CP). The monogeneans infectingM. salmoideswereClavunculus unguisandAcolpenteron ureteroecetes(collected in all localities), as well asSyncleithrium fusiformis,Haplocleidus furcatus,Clavunculus bifurcatusandUrocleidus principalis(CS).Clavunculus unguishad the highest prevalence in fish from all reservoirs. The abundance of monogeneans was generally greater in late spring to autumn than in winter. Although season was not correlated with abundance (rs= 0.0934,PPA. ureteroecetes. Our findings include five new geographic records forC. unguis,S. fusiformis,H. furcatusandC. bifurcatus.

Resumen La tripanosomiasis americana es una enfermedad potencialmente letal causada por el protozoario hemoflagelado Trypanosoma cruzi. Esta enfermedad desatendida afecta entre 6 a 7 millones de personas en el mundo. Actualmente existen solo dos medicamentos para tratar la enfermedad, benznidazol y nifurtimox, ambos efectivos si se administran en la fase aguda, aunque su actividad disminuye en la fase crónica, también induce efectos secundarios significativos. El objetivo de este estudio fue analizar la actividad tripanosomicida de los extractos metanólicos de Hematoxilum brasiletto, Marrubium vulgare, Schinus molle, and Cympongon citratus contra T. cruzi epimastigotes, seguido de la separación cromatográfica e identificación de los compuestos activos del mejor candidato por medio de reacciones químicas coloridas y también, determinar su efecto citotóxico en cultivos de linfocitos humanos y Artemia salina. El extracto de H. brasiletto presentó la mejor actividad anti-T. cruzi con una concentración inhibitoria (CI) de 543 µg/mL; seguida en orden descendiente por M. vulgare (CI50 = 647 µg/mL), S. molle (CI = 827 µg/mL)y finalmente, C. citratus (CI = 1 210 µg/ mL). La fracción cromatográfica Fr22 de H. brasiletto presentó la mejor efectividad tripanosomicida (CI = 0.238 mg/ mL) que las otras fracciones o el extracto completo, además no presentaron efecto citotóxico contra linfocitos o A. salina. Los compuestos activos fueron identificados como taninos, quinonas, flavonoides y sesquiterpenlactonas. En conclusión, fueron identificados los compuestos activos contra T. cruzi en H. brasiletto los cuales no tuvieron efecto citotóxico. De acuerdo a nuestros resultados, el extracto de H. brasiletto podría ser usado como tratamiento alternativo para la enfermedad de Chagas, sin embargo, se necesitan estudios adicionales para probar su actividad y dosis en un modelo murino con la completa identificación de los compuestos activos, sobre los cual se está investigando. Abstract American trypanosomiasis is a potentially lethal disease caused by the hemoflagellate protozoanTrypanosoma cruzi. This neglected disease affects from 6 to 7 million people worldwide. Currently there are only two medicines to treat this disease: beznidazol and nifurtimox, both effective if they are administrated in the acute phase of infection, although their effectiveness fades away in the chronic phase; it also induces significant side effects. The aim of this study is to screen the trypanocidal activity of methanolic extracts from Hematoxilum brasiletto, Marrubium vulgare, Schinus molle, and Cympongon citratus,against T. cruzi epimastigotes, followed by the chromatographic separation, and identification of active compounds of the best candidate by colored chemical reactions; furthermore, it was also determined their cytotoxic effect in human lymphocytes and the brine shrimp Artemia salina. The extract of H. brasiletto showed the highest anti-T. cruzi activity with a inhibitory concentration (IC50) of 543 µg/mL; in descending order, it was followed by M. vulgare (IC50 = 647 µg/mL), S. molle (IC = 827 µg/mL) and finally, C. citratus (IC = 1 210 µg/mL). The chromatographic fraction Fr22 from H. brasiletto showed the best anti-T. cruzi effectivity (IC50 = 0.238 mg/mL), when compared to the other fraction or the whole extract, with no cytotoxic effect against human lymphocytes or A. salina. The active compounds were identified as tannins, quinones, flavonoids and sesquiterpenlactones. In conclusion, active compounds against T. cruzi were identified for the first time in H. brasiletto, with non-cytotoxic effects. The H. brasiletto extract, according to our results, could be used as an alternative treatment for the Chagas disease; however, additional studies will be necessary to test their activity and doses in a murine model, with the complete identification of the active compounds, on which we are investigating.

Resumen Introducción. La pediculosis capitis es un problema recurrente que afecta anualmente de 6 a 12 millones de niños; no existen datos epidemiológicos en el estado de Nuevo León, y en México son escasos, por lo cual se necesitan estudios fundamentados para diseñar estrategias de control basadas en los factores que predisponen a la infestación por piojos. Objetivo. Determinar la prevalencia de Pediculus capitis en niños de educación primaria para detectar factores de riesgo y conocer las características individuales y las condiciones socioeconómicas asociadas estadísticamente con la infestación. Materiales y métodos. Se incluyeron 840 escolares de seis municipios, previa firma del consentimiento informado por parte de los padres y de los niños. Los ectoparásitos se recolectaron en cada niño infestado utilizando un peine fino. Los participantes contestaron una encuesta que incluía variables individuales y socioeconómicas, como la edad, el sexo, el grado escolar, las características del cabello, el hacinamiento y la pediculosis en hermanos, entre otras. Resultados. La prevalencia de pediculosis capitis en los niños fue de 28 % (235/840), con una mayor prevalencia en las niñas (33,7 %; 140/417); los niños del quinto grado (10 a 11 años) fueron los más afectados (6,2 %; 52/840). El sexo femenino, el cabello largo y el nivel escolar de los padres se asociaron significativamente con la pediculosis capitis. Conclusiones. Los resultados demostraron que la prevalencia de pediculosis capitis en Nuevo León es una de las más altas de México y que es un problema real de salud pública,por lo cual es importante establecer programas de prevención en la escuela y en el hogar para disminuirla o controlarla con la ayuda de las autoridades de salud pública. Abstract Introduction: Pediculosis capitis is a recurring problem affecting 6 to 12 millions of children annually; there are no epidemiological data on this subject in the state of Nuevo León, and there are few in México. Therefore, new contributions are needed to design control strategies based on factors that may predispose to head lice infestation. Objective: To determine the prevalence of Pediculus capitis in primary school children and to evaluate risk factors and individual or socioeconomic characteristics statistically associated with infestation. Materials and methods: We included 840 schoolchildren from six municipalities after parents and children signed an informed consent. Ectoparasites were collected from infested children using a fine-toothed comb. Participants were interviewed using a questionnaire on individual and socioeconomic variables including age, gender, education, hair characteristics, overcrowding, and siblings with pediculosis, among others. Results: The overall prevalence of head lice in schoolchildren was 28% (235/840), the highest prevalence was among girls (33.7%, 140/417), and children from the fifth grade (10-11 years old) were the most affected (6.2%; 52/840). Female gender, long hair and the father's education level were significantly associated with P. capitis. Conclusion: Our results showed that the P. capitis prevalence in Nuevo León is one of the highest in Mexico, that it constitutes a real public health problem,and that there is need to establish prevention programsat home and school to decrease or to controlP. capitis with the support of public health authorities.

The present study assessed the prevalence of infectious agents in Litopenaeus vannamei culture systems (intensive, semi-intensive, and extensive) on farms located in Tamaulipas, Mexico. We also analyzed the statistical relationship between these agents and the physicochemical parameters related to the aquatic environment during the summer-autumn of 2008 and the spring–summer of 2009. Acineta sp. at the Reynosa farm, showed a significant correlation with temperature and was the only protozoan found at this farm, which uses semi-intensive culturing with underground water, and showed the best conditions related to lower impacts of infectious diseases. La Pesca shrimp farm uses water from the Laguna Madre estuary and an extensive culture system. Epistylis sp. at the La Pesca farm and the Moron farm showed a significant relationship with turbidity; the dependence of Nematopsis sp. on temperature at La Pesca was highly significant. The filamentous bacterium, Leucothrix mucor , was found at the Moron farm, which uses an intensive production system with freshwater from the Tigre River. To our knowledge, this report is the first to analyze the relationship of this filamentous bacterium with water quality. These results could provide important information for future epidemiological studies to facilitate better resource management and the prevention of infectious or parasitic diseases in farmed shrimp.

White spot syndrome virus (WSSV) was first reported in farmed Litopenaeus vannamei stocks in Sinaloa and Sonora, Mexico during 1999 and continues to cause severe shrimp losses. WSSV genes encoding nucleocapsid (VP26 and VP15) and envelope proteins (VP19 and VP28) of a Mexican isolate were cloned in the pMosBlue vector. The nucleotide sequences of these genes were compared with WSSV isolates in GenBank. VP15 is highly conserved, and VP26 showed 99% homology to a Chinese isolate. The VP28 fragment demonstrated 100% homology to the majority of the isolates analysed (UniProt accession no. Q91CB7), differing from two Indian WSSV and one Chinese WSSV isolates by two non-conserved and one conserved replacements, respectively. Because of their highly conserved nature, these three structural proteins are good candidates for the development of antibody-based WSSV diagnostic tools or for the production of recombinant protein vaccines to stimulate the quasi-immune response of shrimp. In contrast, VP19 of the Mexican isolate was distinguishable from almost all isolates tested, including an American strain of WSSV (US98/South Carolina, GenBank accession no. AAP14086). Although homology was found with isolates from Taiwan (GenBank accession no. AAL89341) and India (GenBank accession no. AAW67477), VP19 may have application as a genetic marker.

This paper describes the first systematic monitoring conducted in 2002 at shrimp farms in Sinaloa and Sonora (Mexico) for the presumptive and confirmative diagnosis of necrotizing hepatopancreatitis bacterium (NHPB) in Litopenaeus vannamei. Light microscopy (wet mounts and hematoxilin-eosin-stained sections of hepatopancreas) showed atrophy of the hepatopancreas, strangulation and necrosis of the hepatopancreatic tubules, with masses of NHPB within the tubular epithelium, hemocytic infiltrates and tubular melanization. The gene encoding the 16S rRNA (16S rDNA) of NHPB was amplified by polymerase chain reaction (PCR) from clinical specimens and the bacteria isolated using Percoll density gradient centrifugation. Negative-stain transmission electron microscopy revealed pleomorphic bacteria, most of them ovoid or rod-shaped (0.2 µm wide and 0.6–0.9 µm long), and a helical form demonstrating seven to twelve spiral turns (0.23 µm wide and 2.43–5.27 µm long). Several severe epizootics of commercially grown L. vannamei occurred during the study period and the mortality was attributed to NHPB infection. Using PCR and microbiological analyses, other etiologic agents, such as white spot syndrome virus, infectious hypodermal and hematopoietic necrosis virus, hepatopancreatic parvovirus and vibriosis, were ruled out as contributory factors.

Introduction: Four species of triatomines have been reported in Nuevo Leon, northeast (NE) Mexico, but Triatoma gerstaeckeri has only been recorded from a peridomestic dwelling. Objectives: To assess the natural infection index (NII) of Trypanosoma cruzi in triatomines and the infestation index (II) of T. gerstaeckeri collected in a suburban locality, and to collect histopathological data to understand tissue tropism of the regional T. cruzi strain (strain NE) obtained from the vectors collected after an experimental inoculation in Mus musculus. Materials and methods: Triatomines were collected from 85 houses and peridomiciles in Allende, Nuevo Leon. Stool samples were obtained to determine the T. cruzi NII and were used in an experimental mice infection. Results: A total of 118 T. gerstaeckeri were captured, and 46 (adults and nymphs) were collected inside the same house (II=1.17%). Thirty-seven reduvids were infected with T. cruzi (NII=31.3%). Tissue tropism of the T. cruzi NE strain was progressive in skeletal muscle, myocardial, and adipose tissues and was characterized by the presence of intracellular amastigotes and destruction of cardiac myocells. Conclusions: The presence of naturally infected domiciliary vectors is an important risk factor for public health in the region considering that these vectors are the principal transmission mechanism of the parasite. The T. cruzi NE strain has similar virulence to that of other Mexican and Texan strains and caused chagasic infections in 11 of 12 mice.

White spot syndrome is a viral disease affecting wild and farm crustaceans that serve as reservoirs. Previous reports have demonstrated high genomic variation in WSS viruses (WSSV) isolated from distinct geographical regions. In this study, we collected wild shrimps (Litopenaeus stylirostris), crabs (Callinectes arcuatus) and farmed shrimp (L. vannamei) in Sonora, Mexico, between 2008 and 2010. DNA was extracted, and the variable regions and transposase genes were subjected to PCR and sequencing. Compared to strains of WSSV from other sites, Mexican samples exhibited a distinct number of repeat units (RUs) in ORF94, ORF75 and ORF125, which ranged between 1-11, 3-15, and 8-11 RUs respectively, and a unique single nucleotide polymorphism (SNP) at position 48 of ORF94. A total of six Mexican genotypes were found in organism from shrimp farm and natural environment.

Chagas disease has become frequent in non-endemic areas, where it can be transmitted by blood transmis- sion. Therefore, we explored seroprevalence of anti- Trypanosoma cruzi antibodies among blood donors at the Cardiology Hospital, Mexican Institute of Social Security at Monterrey, Nuevo Leon, by both an enzyme-linked immunosorbent assay and indirect hemagglutination. Blood samples from 1,000 healthy blood donors were selected. A seropositivity of 2.8% was shown among the studied population, of which 2.59% (21/809) were inhabitants of Nuevo Leon, whereas 3.07% (2/65) and 3.96% (5/126) were from Coahuila and Tamaulipas, respectively. Our result is higher than that of a previous study from 1998, where a prevalence of 0.5% was reported. This once again corroborates the importance of installing a surveillance program to detect and prevent the transfusion of T. cruzi from asymptomatic blood donors in blood banks located in urban cities recognized as non-endemic. of Nuevo Leon and neighbor states (mainly Coahuila and Tamaulipas). Study population. The sample was determined with an estimated prevalence for T. cruzi antibodies of 0.5%, reported previously. 5 A sample size of 1,000 blood donors (8.3%) was calculated from a total of 12,000 donors per year, with an absolute precision of 1.96, confidence level of 97.5%, and E = 1.36 , which exceed the calculated sample size. Nine hundred twenty-six men and seventy-four women were randomly selected, with a female:male ratio of 1:12.5, as representative of the sex composition of the larger donor population (constituted mainly by relatives or friends' patients) at the Cardiology Hospital. According to the protocol described in the Technical Norm for Blood Banks in Mexico, the criteria included age between 18 and 50 years, weight > 50 kg ( Table 1 ), clinically healthy, and seronegative for hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis B virus surface antigen (HBsAg), Brucella abortus (BrA), venereal disease (VDRL), and human immunodeficiency virus (HIV). Ethical consideration. The study protocol was reviewed and approved by the ethics committee of the Universidad Autonoma de Nuevo Leon and was performed according to protocol described in the Technical Norm for Blood Banks in Mexico (IMSS). Serologic test for Chagas disease. The samples from blood donors were collected from a peripheral vein using a Vacutainer system. The serum was separated by centrifugation (1,200 g for 10 minutes), aliquoted in 1.5-mL tubes, and stored at �20°C until use. 2

The aim of this study was to screen the trypanocidal activity of plants used in traditional Mexican medicine for the treatment of various diseases related to parasitic infections. Cultured Trypanosoma cruzi epimastigotes were incubated for 96h with different concentrations of methanolic extracts obtained from Artemisia mexicana, Castela texana, Cymbopogon citratus, Eryngium heterophyllum, Haematoxylum brasiletto, Lippia graveolens, Marrubium vulgare, Persea americana, Ruta chalepensis and Schinus molle. The inhibitory concentration (IC50) was determined for each extract via a colorimetric method. Among the evaluated species, the methanolic extracts of E. heterophyllum, H. brasiletto, M. vulgare and S. molle exhibited the highest trypanocidal activity, showing percentages of growth inhibition between 88 and 100% at a concentration of 150μg/ml. These medicinal plants may represent a valuable source of new bioactive compounds for the therapeutic treatment of trypanosomiasis.

This study aimed to document the geographic distribution of Ixodes tick species in dogs and the prevalence of Borrelia burgdorferi s.l. in adult ticks and blood samples by amplification of the ospA region of the B. burgdorferi genome. The study area included nine localities in Nuevo Leon state. DNA amplification was performed on pools of ticks to calculate the maximum likelihood estimation (MLE), and the community composition (prevalence, abundance, and intensity of infestation) was recorded. A total of 2,543 adult ticks, representing four species, Rhipicephalus sanguineus, Dermacentor variabilis, Rhipicephalus (Boophilus) annulatus, and Amblyomma cajennense, were recorded from 338 infested dogs. Statistically significant correlations were observed between female dogs and infestation (P = 0.0003) and between R. sanguineus and locality (P = 0.0001). Dogs sampled in Guadalupe and Estanzuela were positive by PCR (0.9 %) for B. burgdorferi. Rhipicephalus sanguineus had the highest abundance, intensity, and prevalence (10.57, 7.12 and 94.6, respectively). PCR results from 256 pools showed that four pools were positive for D. variabilis (1.6 %), with an MLE of 9.2 %; nevertheless, it is important to consider that in the area under examination probably other reservoir hosts for D. variabilis and B. burgdorferi are present that, very likely, play a much more important role in the ecology of Lyme borreliosis than dogs, which could be considered in future studies.

Objective. To determine the prevalence of Trypanosoma cruzi in triatomines from Nuevo Leon using the standardization of an improved enzyme-linked immunosorbent assay test. Materials and Methods. From July to September 2005, 52 triatomines were captured in General Teran, a municipality located in Nuevo Leon. They were analyzed using optical microscopy (OM) and a polymerase chain reaction (PCR), as standards of reference, to develop a technique for detecting the parasite using enzyme-linked immunosorbent assay (ELISA). Results. Using OM and PCR, 31 triatomines were found to be positive and 21 negative. Using ELISA, 27 samples were identified as positive and 25 negative (specificity 100%, sensitivity 87%, negative predictive value 84%, and positive predictive value 100%). The prevalence of infected triatomines was 59.61% with OM and PCR, and 51.92% with ELISA. Our data confirm that the ELISA assay in triatomines is a fast, reliable and useful tool. Conclusions. Since it was possible to simultaneously analyze a large number of samples with high sensibility and specificity values, the ELISA test proves to be useful for new epidemiologic studies having a high number of vectors. It is also less expensive than PCR. It is therefore recommended for epidemiological and preventive surveillance programs as a first screening test before conducting a confirmatory test using PCR.

Background American trypanosomiasis is a major disease and public health issue, caused by the protozoan parasite Trypanosoma cruzi. The prevalence of T. cruzi has not been fully documented, and there are few reports of this issue in Nuevo Leon. The aim of this study was to update the seroprevalence rate of T. cruzi infection, including an epidemiological analysis of the risk factors associated with this infection and an electrocardiographic (ECG) evaluation of those infected. Methods Sera from 2,688 individuals from 10 municipalities in the state of Nuevo Leon, Mexico, were evaluated using an enzyme-linked immunosorbent assay and an indirect hemagglutination assay. An ECG case–control study was performed in subjects seropositive for T. cruzi and the results were matched by sex and age to seronegative residents of the same localities. A univariate analysis with χ2 and Fisher’s exact tests was used to determine the association between seropositivity and age (years), sex, and ECG changes. A multivariate analysis was then performed to calculate the odd ratios between T. cruzi seropositivity and the risk factors. Results The seropositive rate was 1.93% (52/2,688). In the ECG study, 22.85% (8/35) of the infected individuals exhibited ECG abnormalities. Triatoma gerstaeckeri was the only vector reported. The main risk factors were ceiling construction material (P ≤ 0.0024), domestic animals (P ≤ 0.0001), and living in rural municipalities (P ≤ 0.0025). Conclusions These findings demonstrate a 10-fold higher prevalence of Chagas disease than previously reported (0.2%), which implies a serious public health threat in northeastern Mexico. The epidemiological profile established in this study differs from that found in the rest of Mexico, where human populations live in close proximity to domiciliary triatomines.

Objetivo. Determinar la prevalencia de Trypanosoma cruzi en triatominos Triatoma gerstaeckeri de Nuevo León, mediante la estandarización de una técnica inmunoenzimática. Material y métodos. Se colectaron 52 chinches en General Terán, N.L. desde julio hasta septiembre de 2005, las cuales se analizaron por microscopía óptica (MO) y reacción en cadena de la polimerasa (PCR) como estándares de referencia para establecer una técnica de detección del parásito por el ensayo inmunoabsorbente ligado a enzimas (ELISA). Resultados. Por MO y PCR, 31 triatominos fueron positivos y 21 negativos; por ELISA los resultados difieren con 27 positivos y 25 negativos (100% de especificidad, 87% de sensibilidad, 84% de valor predictivo negativo y 100% de valor predictivo positivo). Por MO y PCR, la prevalencia de triatominos infectados fue de 59.61% y por ELISA, de 51.92%; por lo que se confirmó la utilidad, rapidez y elevado índice de confianza del ensayo de ELISA. Conclusión. Los resultados obtenidos por la técnica de ELISA son útiles para enfocar los nuevos estudios epidemiológicos con un mayor número de vectores, ya que fue posible analizar simultáneamente la mayor cantidad de muestras, con niveles de sensibilidad y especificidad elevados y a menor costo que el PCR; por lo tanto, se recomienda para programas de vigilancia epidemiológica preventiva como primera prueba de tamizaje, antes de realizar análisis confirmatorios por PCR.

Se reporta la presencia del virus de la necrosis hipodérmica y hematopoyética infecciosa (IHHNV) y del virus del síndrome de Taura (TSV) en camarones silvestres Litopenaeus setiferus (camarón blanco) y Farfantepenaeus aztecus (camarón café) capturados en el estero de La Pesca, en La Laguna Madre, Tamaulipas, México. El estudio se realizó por histopatología y amplificación de ácidos nucleicos. La prevalencia de TSV fue 6,6% (12/180) y 4,4% para IHHNV (8/180). La mayoría de los casos se presentaron de noviembre a marzo (15/180). La presencia de estos virus en camarones silvestres de La Laguna Madre, alerta sobre el riesgo en que se encuentran las poblaciones silvestres y las granjas camaroneras colindantes con el Golfo de México, por lo que se sugiere establecer un programa de monitoreo sanitario y verificar el impacto de ambos virus en camarones de granjas vecinas a La Laguna Madre.

The freshwater channel catfish ( Ictalurus punctatus, Rafinesque, 1818) is one of the world-wide highlight species in aquaculture. Despite the growing presence of this fish in the farming industry, its parasitic fauna is rarely studied in Mexico. This survey was designed to provide insight into the occurrence and abundance of parasitic fauna of I. punctatus and to contribute to the national inventory of parasites of this fish. This study was performed at the follow - ing three dams in the state of Nuevo Leon, Mexico: Cerro Prieto, Rodrigo Gomez, and El Cuchillo-Solidaridad. Seven helminths and 1 copepod species were recorded from the 24 I. punctatus collected. This record consists of a total of 4,687 parasites, of which 108 were endoparasites and 4,579 ectoparasites. Our findings demonstrate a great diversity of helminth parasites, including Ligictaluridus floridanus , and Corallobothrium fimbriatum , and new locality records for Megalogonia ictaluri , Centrocestus formosanus , Diplostomum ( Austrodiplostomum ) compactum , Spiroxys sp., the co - pepod Ergasilus cerastes, and a new host and distribution record was reported for Spinitectus tabascoensis , originally described from I. furcatus from Tabasco, southern Mexico.