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Background: Maize in Mexico exhibits great genetic diversity, maintained by traditional practices of indigenous and non-indigenous communities, the same practices that have led to crop diversification over centuries. As one of the main staple crops worldwide, safeguarding the genetic diversity of maize is paramount to food security. Aims: This study evaluated the genetic diversity and population structure of traditionally cultured maize landraces in a rural seasonal agricultural community in Veracruz, Mexico, in order to learn how traditional practices shape these landraces, and propose strategies for their preservation. Methods: We analysed 118 individual maize samples belonging to five morphotypes (white, yellow, black, red and mottled) with eight microsatellite markers. Results: We encountered high genetic diversity, according to expected heterozygosity (He = 0.61). However, inbreeding coefficient and gene flow values suggested the existence of assortative mating, which causes low genetic differentiation. Population structure analysis identified three genetic pools, independent of grain colour. These findings suggest that all morphotypes belong to the same population, which is sub-structured due to assortative mating and gene flow related to local agronomic management. Conclusions: Current management practices in this community could lead to genetic erosion. In order to preserve diversity, wider regional seed exchange and selection for morphological diversity could be implemented. [ABSTRACT FROM AUTHOR]

The aims of this study were to determine the frequency of egg shedding (percentage of egg-positive faecal samples) and faecal egg counts (FEC) over 13 months in two different breeds of ewes, both pregnant and non-pregnant, in a mountainous region of central Mexico. Additionally, the effect of ivermectin and albendazole treatments on FEC reduction was recorded. The study also aimed to relate temperature and rainfall to FEC. The gastrointestinal nematode (GIN) third-stage larvae genera recovered from both faeces and grassland pastures in a temperate region were also assessed. Faecal samples were collected from ewes at monthly intervals for 13 months to investigate the FEC population of GIN larvae, their concentration and genera in grass samples collected from grazed and rested pastures. Egg-shedding frequency ranged from 0 to 92% and FEC from 0 to 12,000 eggs per g faeces (epg), with counts in Suffolk higher than in Dorset ewes. The identified genera were Haemonchus, Trichostrongylus, Teladorsagia, Cooperia, Oesophagostomum, Bunostomum, Nematodirus and Strongyloides. Haemonchus and Trichostrongylus were the most common genera. The number of L3 was higher in grazing lands than in those at rest. The highest FEC were recorded in the dry season due to peripartum, but the highest L3 counts were recorded in the rainy season. The coexistence of species of different geographical distributions at this site may be because there is a confluence of Nearctic and Neotropical geographic regions; thus, despite the temperate climate, tropical species can be found. Additionally, this study suggests that increasing temperatures could favour the presence of different tropical GIN species together with typical temperate-zone GIN species. [ABSTRACT FROM PUBLISHER]

Pseudomonas syringae pv. tomato has been observed in the fields in Sinaloa causing typical symptoms of bacterial speck. During the 2004-2005 growing seasons atypical symptoms were observed in tomato varieties grown in Sinaloa, consisting of external necrosis of stems, petioles, peduncles and fruit calyxes. Although the disease affected 80-90% of the foliage, there were no speck symptoms on fruit. The objectives of this study were to: ( a) identify the causal agent of the disease, ( b) determine the sensitivity of the pathogen to various antibiotics in vitro and ( c) test their efficacy for controlling the disease in tomato plants under greenhouse conditions. The results of the present study indicate that biochemical and physiological characteristics as well as the molecular studies of bacterial isolates associated with the yellow halo spot and external necrosis of the stem of tomato are closely related to P. syringae pv. tomato, although whether these isolates indeed belong to pathovar tomato needs further assessment. The efficacy of gentamicin sulfate and oxytetracycline chlorhydrate in vitro, and in planta under greenhouse conditions, represents a possible option for the chemical control of the disease under field conditions. The results also indicate a reduced sensitivity of the characterized isolates to copper hydroxide as compared with the above mentioned antibiotics in northern Sinaloa. [ABSTRACT FROM AUTHOR]

Abstract: The possible relationships between stable fly infestation with dairy farm facilities and sanitation practices were studied using path analysis. Twelve dairies located in four counties of Aguascalientes dairy region were selected. The dairies were monitored from May to November 2003. In each occasion, fly infestation, individual physical facility characteristics, and sanitation practices were recorded. In all, 11 independent variables were involved in the study and related variables were grouped together and analyzed in two blocks by path analysis for each one of five population events (begin of fly season, first peak, fluctuation, second peak and decrease). There were significant regression coefficients only in the second peak for two variables, the distance to the silos and the distance to the dung heap (r 2 =0.96 for the full model). Among the 11 variables examined in the study, none had a statistical significant indirect contribution to fly infestation; direct contribution was observed for distance to the silos and for distance to the dung heap variables. However, only the distance to the silos variable was significantly related to stable fly Infestation. [Copyright &y& Elsevier]

Laser-induced breakdown spectroscopy (LIBS) was used to monitor macro- and micro-nutrients in pine trees exposed to two mayor activity periods of the Popocatépetl volcano in Mexico. Due to the high spatial resolution achieved with LIBS, a separate analysis of earlywood and latewood was performed. An increased concentration of potassium was found in earlywood, while calcium and sodium decreased. Besides, it was observed a similar temporal behavior for elements belonging to the same chemical group. The alkali earth metals Ca, Mg and Sr showed decreasing trends through the investigated years while alkali metals Na and K remain nearly constant. LIBS was able to detect significant changes in Ca, Mg, Na and Sr intensities coincident with the 1919 Popocatépetl's eruptive period and after the volcanic activity starting at the end of 1999. Temporal evolution of the emission intensities is in agreement with the elemental composition obtained with inductively coupled plasma optical emission spectrometry. Unlabelled Image • Pine tree rings of the Popocatépetl volcano area were analyzed by LIBS. • Increased availability of K in earlywood while Ca and Mg in latewood was measured. • Elements belonging to the same chemical group presented similar temporal trends. • Increment of Na, Mg, Si, K, Ca, Cu and Sr due to eruptions was detected. • The obtained behavior was in agreement with the measured values with ICP-OES. [ABSTRACT FROM AUTHOR]

Purpose: This work aimed to evaluate the impact of a guaranteed access program to imatinib on the survival of patients with Chronic Myeloid Leukemia., Methods: We carried out a retrospective, observational, and analytical study of the database of patients diagnosed with Chronic Myeloid Leukemia of the Instituto Nacional de Cancerología and the Hospital General de México Dr. Eduardo to assess overall survival based on guaranteed access or not to imatinib., Results: With an average follow-up of 99 months, all patients' estimated 20-year overall survival was 72% (95% CI, 76-67). A significant difference was found in the 20-year survival probability in favor of patients with guaranteed access 76% (95% CI, 81-71) vs. 61% (95% CI, 69-52) (p < 0.001), in addition to those in which they had better attachment 81.2% (95% CI, 85-76) vs. 44.9% (95% CI, 52-37) (p < 0.001)., Conclusion: CML is the most frequent chronic leukemia in Mexico. It mainly affects the economically active population (mean age 40), and the prognosis in our country has improved, emulating developed countries; however, the results depend on access to treatment and proper monitoring., Competing Interests: Declarations Conflict of interest The authors declare no competing interests. Ethical approval The Hospital General de México Dr. Eduardo Liceaga and Instituto Nacional de Cancerologia, a research ethics committee, approved the study, which was performed per the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Crops contamination with aflatoxins (AFs) and zearalenone (ZEA) threaten human and animal health; these mycotoxins are produced by several species of Aspergillus and Fusarium . The objective was to evaluate under field conditions the influence of the wet season on the dissemination of AF- and ZEA-producing fungi via houseflies collected from dairy farms. Ten dairy farms distributed in the semi-arid Central Mexican Plateau were selected. Flies were collected in wet and dry seasons at seven points on each farm using entomological traps. Fungi were isolated from fly carcasses via direct seeding with serial dilutions and wet chamber methods. The production of AFs and ZEA from pure isolates was quantified using indirect competitive ELISA. A total of 693 Aspergillus spp. and 1274 Fusarium spp. isolates were obtained, of which 58.6% produced AFs and 50.0% produced ZEA (491 ± 122; 2521 ± 1295 µg/kg). Houseflies and both fungal genera were invariably present, but compared to the dry season, there was a higher abundance of flies as well as AF- and ZEA-producing fungi in the wet season ( p < 0.001; 45.3/231 flies/trap; 8.6/29.6% contaminated flies). These results suggest that rainy-weather conditions on dairy farms increase the spread of AF- and ZEA-producing Aspergillus spp. and Fusarium spp. through houseflies and the incorporation of their mycotoxins into the food chain.

The objective of this study was to describe the epidemiology of Toxoplasma gondii and Neospora caninum infection by estimating seroprevalence and its association with certain risk factors in goats from Aguascalientes, Mexico. A total of 150 blood samples was taken from 10 farms and serum samples were subjected to enzyme-linked immunosorbent assay indirect test to detect T. gondii and N. caninum antibodies; the association between seroprevalence and some potential risk factors was estimated through logistic regression analysis. The general seroprevalence for T. gondii was 12.6%, observed in the farms in a range of 6.6 to 60%, finding seropositive animals in 80% of them; for N. caninum the seroprevalence was 3.3% and in farms a range of 6.6 to 13.3% was identified and 30% of them had at least 1 seropositive animal. The coinfection was 0.66%. The risk analysis for T. gondii identified a history of abortions (odds ratio 9.25) as a factor associated with seroprevalence; for N. caninum, no risk factor was identified., (© American Society of Parasitologists 2023.)

Rhipicephalus sanguineus s.l. is an intra- and peridomiciliary tick of medical and veterinary importance, whose control is carried out through the application of various ixodicides, to which it can develop resistance. The objective of this work was to determine the discriminant doses (d.d.) to identify resistance against three ixodicides - fipronil, flumethrin and coumaphos - in R. sanguineus s.l. larvae originating from Mexico. Engorged ticks were collected from naturally infested dogs residing in rural communities in five Mexican states; the dogs had no history of recent treatment with ixodicides. All ticks were identified as R. sanguineus s.l. They were incubated for 25 days and their progeny was used in the larval package test (LPT) to be exposed to d.d. as determined in Rhipicephalus microplus, and those that were susceptible were analyzed using the LPT with six concentrations, for fipronil from 0.1 to 0.003125%, for flumethrin from 0.02 to 0.000625% and for coumaphos from 0.4 to 0.0125%. Mortality was analyzed with Probit methodology, to calculate the 50 and 99% lethal concentrations (LC50 and LC99). The d.d. was determined as a consensus value by multiplying the LC99 value × 2. Nine double susceptible samples (fipronil + flumethrin) and one triple susceptible sample (fipronil + flumethrin + coumaphos) were found; the d.d. determined were fipronil 0.05%, flumethrin 0.01% and coumaphos 0.43%. These doses can be used to rapidly and inexpensively identify resistant populations in samples collected in the field., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Context and Purpose: This work aimed to study the seroprevalence of natural infection by T. gondii in different population segments of dogs from Aguascalientes, Mexico as well as its possible association with some risk factors., Methods: The study included 210 clinically healthy dogs from three population segments: rural, stray and pet. A blood serum sample was collected on a single occasion and processed by indirect immunofluorescence considering a dilution of 1:16 as a positive reaction; the association between the presence of antibodies and the potential risk factors was estimated with logistic regression., Results: The overall prevalence of anti-T. gondii antibodies in the studied population was 59% (123/210; CI 95% 51-65) being different between population segments, in rural dogs 74% (59/80; CI 95% 62-82), in stray dogs 60% (48/80; CI 95% 48-70) and in pet dogs 32% (16/50; CI 95% 19-46), the titers of the positive sera were in a range of 1:16-1:128. In rural dogs the seroprevalence according to the municipality was in a range of 55% to 100% finding positive dogs in all the studied municipalities. The zootechnical function of guarding the property in rural dogs was identified as a risk factor (OR 2.4), while in pet dogs it was living with cats (OR 7) as well as sharing the drinking water container (OR 4); in stray dogs it was not possible to identify any risk factor., Conclusions: This study documents the wide presence of anti-T. gondii antibodies in the population groups examined, this being more important in rural dogs., (© 2023. The Author(s) under exclusive licence to Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)

The objectives of the study were to estimate the prevalence of anti-Toxoplasma gondii antibodies in free-range chickens in Aguascalientes, Mexico, its association with certain risk factors, and the frequency of parasite DNA in the heart. Eighty-one small rural family farms were included, and blood and heart samples were taken from 150 clinically healthy, adult, free-range chickens. Serum samples were processed by indirect immunofluorescence antibody test considering a dilution of 1:16 as a positive reaction, while the DNA detection was done by PCR. The correlation between the presence of antibodies and the potential risk factors was estimated with logistic regression. The overall seroprevalence in the examined populations was 67%, with a range from 33% to 100% among municipalities, and 78% of the farms having at least one seropositive bird. The PCR test identified the presence of parasite DNA for one case only. Among the variables, the presence of cats and the presence of other animal species on the farm were the ones that had the highest values, while the presence of feral cats and the presence of noxious fauna were also identified as potential risk factors. The results indicate high soil contamination by T. gondii oocysts, which implies the active role of cats living on the farms.

Ehrlichia canis has gained importance over the years as a zoonotic bacterium, nevertheless in Mexico is unknown the extent of the problem in animals and public health. The country had a few studies carried out locally using serology and molecular tests as diagnostic methods. Ehrlichiosis is not considered endemic in the central valley of Mexico, because the climatic conditions in the region have not allowed the vector (Rhipicephalus sanguineus) to establish itself adequately, therefore, diagnosis is not used in clinical practice in this area. A nested PCR (nPCR) offers rapid results with high sensitivity and specificity regardless of cost. The use of a recombinant positive control provides the advantage of timely diagnosis, follow-up treatment and allows the clinician to decide. In this work, the nPCR reported by Wen et al. (J Clin Microbiol 35(7):1852-2185, 1997) was used for the diagnosis of E. canis by modifying the reaction conditions to improve the detection of the test. We constructed a recombinant positive control to nPCR as diagnostic technique for E. canis, also we modified the reaction conditions to improve detection of the test which allowed the diagnosis of E. canis in dogs in the Mexican Republic using 53 samples from dogs with positive serological diagnosis of Ehrlichiosis, some of them from the valley of Mexico. Currently, this nPCR is offered to public at the Faculty of Veterinary Medicine and Zootechnics of the National Autonomous University of Mexico at an accessible cost and allows to begin to generate epidemiological information to know distribution of the bacterium., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The objective of the study was to analyse the prevalence of infection by N. caninum and T. gondii in breeding ewes from central western Mexico. For this purpose, 184 blood samples were collected from sheep in the reproductive stage, which were analysed by ELISA and PCR tests, respectively, and the association between seroprevalence and some management factors was estimated by means of a logistic regression analysis. For N. caninum, a seroprevalence of 15.22% was identified, while the DNA detection in blood was 14.13% (26/184); positive animals were found in 75% of the farms (6/8). The variables poor placental waste management (OR 8.4), abortion history (OR 1.5) and presence of rodents (OR 1.3) were identified as risk factors for N. caninum infection. In the case of T. gondii, a seroprevalence of 61.96% was found, and antibodies were detected in eight farms included in the study; no positive samples were identified for T. gondii by the PCR test. The main identified risk factors for T. gondii were as follows: poor hygiene conditions (OR 12.5), presence of cats (OR 9.5), presence of other domestic animals (OR 5.7), urban context of the farm (OR 9.5) and public water supply (OR 5.3). The seroprevalence of co-infection of T. gondii and N. caninum in breeding ewes was 7% (13/184; 95% CI 6.92-7.20). T. gondii has a high seroprevalence while N. caninum was of lower proportion, and both may be associated with reproductive losses for these herds studied., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Parasites cause losses in animal production. Parasite infection in ruminants has been estimated to be a major problem causing more than 3 billion USD per year, from which 60% corresponds to the sheep industry. Treatment is based on the use of synthetic anthelmintics; however, repeated application or under dosage have resulted in the selection of nematodes resistant to anthelmintics. The objective of the present work was to perform a diagnosis of gastrointestinal parasites in sheep kept under different zootechnical management. Ninety female sheep were used, most of them pregnant. Sampling was performed monthly from December 2015 to June 2016 (flock 5 until April). Fecal samples were collected from the rectum; the McMaster technique was performed, morphological characteristics were observed, oocysts and eggs were counted per gram of feces (opg and epg), frequency and intensity were obtained. Faecal culture was performed for feces that had a positive result, infective larvae were obtained and taxonomically identified. At the end of the study, a dewormer (fenbendazole) was administered and its effect was measured. The frequency of gastrointestinal parasites was 100%. The highest opg was 3,600 (flock 3, March, 2016), the epg for cestodes was 2800 (flock 1, January, 2016) and for gastrointestinal nematodes (GIN) was 25,000 (flock 1, May, 2016); the intensity was variable and it was increased by peripartum. Protists (Eimeria spp), cestodes (Moniezia) and nematodes (Haemonchus, Trichostrongylus, Cooperia, Chabertia ovina. Teladorsagia, Oesophagostomum, Nematodirus and Trichuris ovis) were identified. No previous diagnosis is performed in flocks, and sometimes dewormers are administered, even though resistance to ivermectin and benzimidazole is suspected. Flock management, its feeding system and its conditions were determinant for the observed results; therefore, it is necessary to count with a diagnosis that provides information about the parasitic population and its dynamic, in order to carry out a selective and comprehensive control that has an impact on the animal, human and environmental health., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

The objective of the present study was to investigate the epidemiology of natural infection by N. caninum in free-range chickens from Aguascalientes, Mexico, through identifying the presence of antibodies, its association with certain risk factors, and estimate the frequency of parasite DNA detection in the brain. The study included 150 clinically healthy chickens from 81 small family farms distributed throughout the state, from which blood and brain samples were taken. Serum samples were processed by indirect immunofluorescence considering a dilution of 1:50 as a positive reaction, while the DNA detection was done by PCR; the association between the presence of antibodies and the potential risk factors was estimated through logistic regression. The general anti-N. caninum presence of antibodies in the studied population was 46% (69/150, CI 95% 38-54), with titers of 1:50 in 38, 1:100 in 24, and 1:200 in 7, finding positive cases in 49% of the farms and in 91% of the municipalities that integrate the state. The presence of antibodies found in the municipalities was estimated in a range of 20 to 75%. The frequency of DNA detection was 6% (9/150, CI 95% 2-11). The grain supplementation was identified as the unique risk factor for infection (OR = 2.82; 95% CI, 1.18-6.73, p < 0.019)., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

La pandemia de COVID-19 ha infligido grandes estragos a la población y en especial al personal de salud. Los esfuerzos de reanimación exigen modificaciones potenciales de las guías internacionales existentes de reanimación cardiopulmonar (RCP) debido al elevado índice de contagiosidad del virus SARS-CoV-2. Se considera que hasta 15% de los casos de COVID-19 tiene una enfermedad grave y 5% padece un trastorno crítico con una mortalidad promedio del 3%, la cual varía según sean el país y las características de los pacientes. La edad y las comorbilidades como la hipertensión arterial, enfermedad cardiovascular, obesidad y diabetes incrementan la mortalidad hasta 24%. También se ha informado un aumento reciente del número de casos de paro cardíaco extrahospitalario (PCEH). Aunque el paro cardíaco (PC) puede ser efecto de factores diversos en estos pacientes, en la mayoría de los casos se ha demostrado que el origen es respiratorio, con muy pocos casos de causa cardíaca. Se debe considerar la indicación de iniciar o continuar las maniobras de RCP por dos razones fundamentales: la posibilidad de sobrevida de las víctimas, que hasta la fecha se ha registrado muy baja, y el riesgo de contagiar al personal de salud, que es muy alto., The COVID-19 pandemic is having a large impact on the general population, but it has taken a specially high toll on healthcare personnel. Resuscitation efforts require potential modifications of the present Cardiopulmonary Resuscitation (CPR) international guidelines because of the transmissibility rate of the new SARS-CoV 2 virus. It has been seen that up to 15% of COVID-19 patients have a severe disease, 5% have a critical form of infection and the mean death rate is 3%, although there are significant differences according to the country that reports it and patients’ baseline conditions that include age, presence of arterial hypertension, cardiovascular disease, diabetes or obesity. In these high risk subjects, mortality might go up to 24%. There are also reports of a recent increase in out-of-hospital cardiopulmonary arrest (OHCA) victims. Cardiac arrest (CA) in these subjects might be related to many causes, but apparently, that phenomenon is related to respiratory diseases rather than cardiac issues. In this context, the decision to start or continue CPR maneuvers has to be carefully assessed, because of the low survival rate reported so far and the high contagion risk among healthcare personnel., (Copyright: © 2021 Permanyer.)

The objective of the study was to identify the seroprevalence of anti-Toxoplasma gondii antibodies in sheep herds from 3 municipalities from Jalisco, Mexico, as well as estimate the association between seroprevalence and certain factors presents in the farms. In total, 12 sheep farms that maintain only hair breeds were included in the work. From these farms, 336 blood samples were collected, corresponding 324 to ewes and 12 rams. Serum samples were subjected to ELISA test, and the association between the frequency of antibodies and some potential risk factors was estimated. The overall seroprevalence to anti-T. gondii antibodies in the population studied was 17.8% (60/336; 95% confidence interval [C.I.] 14-22), all farms had positive animals, and the seroprevalence of antibodies ranged between 7 to 32%. Seroprevalence in specific municipalities was 18.7% in Lagos de Moreno, 17.8% in Encarnación de Díaz, and 16.9% in San Juan de los Lagos. Seroprevalence in ewes was 17.5% (57/324; 95% C.I. 13-22), and seroprevalence in rams was 25% (3/12; 95% C.I. 6-57), while among breeds it was 17.8% in Pelibuey (20/112; 95% C.I. 11-26), 16.6% in Kathadin (14/84; 95% C.I. 9-26), 15.4% in Blackbelly (13/84; 95% C.I. 8-25), and 23.2% in Dorper (13/56; 95% C.I. 13-36); no differences were observed among breeds (p < 0.05). The presence of cats on the farms was associated with seroprevalence (odds ratio [OR] 2.8; 95% C.I. 1.8-7.3, p < 0.001), as was the absence of a rodent-control program (OR 1.5; 95% C.I. 0.8-3.2, p < 0.05). No other factors were identified as associated with seroprevalence., (© American Society of Parasitologists 2020.)

The purpose of this study was to describe the prevalence and incidence of Neospora caninum infection in dogs that are in close contact with dairy cattle and to identify possible risk factors associated with the infection in this population. Twenty-four dogs located in 8 different dairy farms of Aguascalientes, Mexico, were evaluated for a 6-mo period. Once a month a sample of serum and a sample of peripheral blood was collected. The serum was used to detect antibodies against N. caninum by means of the indirect immunofluorescence technique, and the blood was used to detect parasite's DNA. The association between seroprevalence and possible risk factors was estimated using logistic regression. The prevalence of anti-N. caninum antibodies was 54% in the first month, 62% in the last month, and the incidence was 8.69%. One farm had no positive cases. Antibody titers ranged from 1:50 to 1:800. Parasite DNA was not detected in any of the samples. Only the age (>6 yr) of the dogs was identified as a risk factor for infection by N. caninum (P ≤ 0.05)., (© American Society of Parasitologists 2020.)

Nematodes of the Libyostrongylus genus are hematophagous parasites found under the ostrich's proventriculus membrane: they are frequent and can cause 50% of mortality in chicks and occasionally death in adults. With the aim of determining the presence of the Libyostrongylus genus in two private collections, one located in Ayapango, State of Mexico and the other in Amacuzac, Morelos, a total of 27 fecal samples were collected between August and December of 2016. Samples were analyzed using the flotation technique. The eggs were quantified using the McMaster technique. Positive samples were cultured to obtain infective larvae and to be identified by their morphometric characteristics. Only 18 samples collected in Ayapango were positive to Libyostrongylus douglassii. This is the first time that L. douglassii is reported in Mexico., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of the present work was to study the dynamics of Fasciola hepatica natural infection in ovines, caprines, bovines and two mollusc species, Lymnaea (Fossaria) humilis and Lymnaea (F.) bulimoides, from 2004 to mid 2007 under normal farm management conditions, and the relation to climate changes. The study was performed in a research centre in the plateau of Mexico. Temperature and rainfall were registered every month, as well as the number and intensity of infection in livestock and molluscs, as determined by coprology and direct observation/cercariae release, respectively. The first two years mammals were treated with clorsulon/ivermectin because the animals were harbouring concomitant intestinal nematode infections and this was the available drug combination. During the second period treatment was with triclabendazole. The temperature ranged from around cero to 30 °C, except during September 2005 to January 2006, when a cold climate prevailed. The rainfall augmented every year in July-August, and slightly in April, 2006. Lymneid snails appeared during or immediately after the rainfall peaks of 2004 and 2006, while few L. humilis and no L. bulimoides were present during the same period of 2005, probably because it was cold. A total of 15564 cercariae were released from molluscs during the wet time of 2004, 76 during 2005 and 368 in 2006. Several peaks of infection in mammals were observed, most occurring up to 4 months after the snails had disappeared. As expected, the weather had strong impact on snails and then on livestock infection. Also, treatment given to livestock was related to reduced cercarieae release five months later. Therefore, the combination of treatment and inspection of snails in the biotopes where the livestock graze may facilitate control of fasciolosis under current farm management., (Copyright © 2010 Elsevier B.V. All rights reserved.)

In this descriptive study we investigated the genetic structure of 513 Mexican indigenous subjects grouped in 14 populations (Mixteca-Alta, Mixteca-Baja, Otomi, Purépecha, Tzeltal, Tarahumara, Huichol, Nahua-Atocpan, Nahua-Xochimilco, Nahua-Zitlala, Nahua-Chilacachapa, Nahua-Ixhuatlancillo, Nahua-Necoxtla, and Nahua-Coyolillo) based on mtDNA haplogroups. These communities are geographically and culturally isolated; parents and grandparents were born in the community. Our data show that 98.6% of the mtDNA was distributed in haplogroups A1, A2, B1, B2, C1, C2, D1, and D2. Haplotype X6 was present in the Tarahumara (1/53) and Huichol (3/15), and haplotype L was present in the Nahua-Coyolillo (3/38). The first two principal components accounted for 95.9% of the total variation in the sample. The mtDNA haplogroup frequencies in the Purépecha and Zitlala were intermediate to cluster 1 (Otomi, Nahua-Ixhuatlancillo, Nahua-Xochimilco, Mixteca-Baja, and Tzeltal) and cluster 2 (Nahua-Necoxtla, Nahua-Atocpan, and Nahua-Chilacachapa). The Huichol, Tarahumara, Mixteca-Alta, and Nahua-Coyolillo were separated from the rest of the populations. According to these findings, the distribution of mtDNA haplogroups found in Mexican indigenous groups is similar to other Amerindian haplogroups, except for the African haplogroup found in one population.

A 19-month study on the prevalence of fasciolosis in 30 naturally infected cows, the presence of infected and non-infected Lymnaea (Fossaria) humilis snails, and variation in soil temperature and humidity is reported. The prevalence of fasciolosis in cattle declined from around 50% in March to 30% in July, then, it increased from August, reaching a plateau of 100% in November-January, before gradually declining thereafter. A rise in soil humidity and temperature in June and July, respectively, which peaked between August and November was observed. In July, L. (F.) humilis snails appeared, but the infection could only be found in these in August and November. The number of infected snails did not reflect the infestation rate in cows, even though the infestation kinetics in both hosts behaved as predicted from the life cycle of the parasite.

Bioassay-guided chromatographic separation of the antimycobacterial extract of the leaves of Piper sanctum afforded 14 new compounds, identified as 2-oxo-12-(3',4'-methylenedioxyphenyl)dodecane (1), 2-oxo-14-(3',4'-methylenedioxyphenyl)tetradecane (2), 2-oxo-16-(3',4'-methylenedioxyphenyl)hexadecane (3), 2-oxo-18-(3',4'-methylenedioxyphenyl)octadecane (4), 2-oxo-14-(3',4'-methylenedioxyphenyl)-trans-13-tetradecene (5), 2-oxo-16-(3',4'-methylenedioxyphenyl)-trans-15-hexadecene (6), 2-oxo-18-(3',4'-methylenedioxyphenyl)-trans-17-octadecene (7), 2-oxo-16-phenyl-trans-3-hexadecene (8), methyl [6-(10-phenyldecanyl)tetrahydropyran-2-yl]acetate (9), methyl 2-(6-tridecyltetrahydro-2H-pyran-2-yl)acetate (10), methyl 2-(5-tetradecyltetrahydro-2-furanyl)acetate (11), 2-oxo-14-(3',4'-methylenedioxyphenyl)-trans-3-tetradecene (12), 2-oxo-16-(3',4'-methylenedioxyphenyl)-trans-3-hexadecene (13), and 2-oxo-16-phenyl-3-hexadecane (14). In addition, p-eugenol (15), methyleugenol (16), Z-piperolide (17), demethoxyyangonin (18), 5,6-dehydro-7,8-dihydromethysticin (19), cepharanone B (20), piperolactam A (21), cepharadione B (22), N-trans-feruloyltyramine (23), and N-trans-(p-coumaroyl)tyramine (24) were obtained from the anti-TBC stem extract of the plant. GC-MS and HPLC analyses of the essential oils of the leaves and stem revealed that safrol (25) was the major component of the oils. Compounds 2, 3, 6, 18-21, and 24 inhibited the growth of Mycobacterium tuberculosis when tested by the MABA assay, with MIC values ranging from 4 to 64 microg/mL.

The aim of the present study was to identify the species that are natural intermediate hosts of Fasciola hepatica in a Research Centre in Chapa de Mota, State of Mexico, Mexico, where temperate and humid conditions prevail. Also, the magnitude and dynamics of the natural infection in four biotopes were analysed. The study was performed between October 2000 and November 2001. The molluscs were collected, identified and studied for trematode infection. Soil humidity and temperature were determined monthly. A total of 4042 snails were collected 3372 (83%) were Fossaria humilis and 670 (17%) F. bulimoides. F. hepatica was present in 2537 (75.2%) and 515 (76.9%) of the two snail species, respectively. Temperature, soil humidity and microenvironment affected the dynamics of the host population and the parasite infestation, with a significant increase from August to November 2001. The highest prevalence was observed in the warmer and more humid biotopes., (Copyright 2004 Elsevier B.V.)

The congenital muscular dystrophies (CMDs) are a heterogeneous group of autosomal recessive disorders. Approximately one half of cases diagnosed with classic CMD show primary deficiency of the laminin alpha2 chain of merosin. Complete absence of this protein is usually associated with a severe phenotype characterized by drastic muscle weakness and characteristic changes in white matter in cerebral magnetic resonance imaging (MRI). Here we report an 8-month-old Mexican female infant, from a consanguineous family, with classical CMD. Serum creatine kinase was elevated, muscle biopsy showed dystrophic changes, and there were abnormalities in brain MRI. Immunofluorescence analysis demonstrated the complete absence of laminin alpha2. In contrast, expression of alpha-, beta-, gamma-, and delta-sarcoglycans and dystrophin, all components of the dystrophin-glycoprotein complex, appeared normal. A homozygous C long right arrow T substitution at position 7781 that generated a stop codon in the G domain of the protein was identified by mutation analysis of the laminin alpha2 gene ( LAMA2). Sequence analysis on available DNA samples of the family showed that parents and other relatives were carriers of the mutation.

Objective: To measure the frequency of goiter and the presence of potential goitrogens in a sample of school-age children and pregnant women., Methods: Cross-sectional study in a purposive sample in three regions, one with known high prevalence of goiter (Huejutla), one with unknown prevalence (Ixmiquilpan) and one with no expected deficiency (Pachuca). Children were sampled from schools and pregnant women from rural reference hospitals. Goiter was evaluated by manual exam and ultrasound., Results: Goiter prevalence in 673 children between 6 and 14 years old was 8% in Pachuca, 9% in Ixmiquilpan, and 14% in Huejutla. In 300 pregnant women, goiter prevalence was 19% in Pachuca, 20% in Ixmiquilpan, and 52% in Huejutla. In 936 interviews on salt consumption, 98% of families consumed table salt, but only 50% of the samples were adequately iodized. Twenty-four percent of families obtained water from wells contaminated with arsenicum and mercury in Pachuca and Ixmiquilpan, and with colibacilli in Ixmiquilpan., Conclusions: Even at the end of the millenium, endemic goiter is still a public health problem in this sample of school-age children and pregnant women. Despite consumption of iodized salt, ingestions of goitrogens may be contributing to the persistence of this problem.

This paper presents the preliminary results of a prospective study undertaken at the Neonatal Unit of the Hospital General de México, S.S.A. (Méx.) conducted to evaluate the possibilities offered by the rooming-in system in this hospital. In both groups, having 250 patients, most of them eutrophic, it was noticed that none of the babies assisted by their mothers showed severe infections, as compared to four babies that showed clinical data compatible with septicemia; these babies were assisted in the nursery in a traditional way, but three of them died. Many of the aspects about the rooming-in system are reviewed, concerning the mothers as well as the babies, and it is finally determined that it is a practical, accessible system that optimizes resources and seems to offer immediate benefits to the mothers as well as to the babies.