Model building and quantitative analysis of a tandem immuno-capturing assay as a screening tool for breast cancer.

The onset of breast cancer appears to occur, on average, a decade earlier in Mexican women in comparison to American or European women. Early detection and prevention of breast cancer are of crucial importance to increase survival and improve quality of life. Based on the molecular elucidation of critical events leading to breast carcinogenesis, a tandem immuno-capturing blood test was developed as a quantitative population screening assay in view of providing a cost-effective and non-invasive alternative to population screening. Clinical analysis of 63 Mexican women within an age group of 35-70, revealed that Interstron activity increases from 800+/-65 IUJPA (Interstron Units) in the asymptomatic normal women to 994+/-100 IUJPA in the symptomatic/benign group, reaching 1289+/-81 IUJPA in the cancerous group. Accordingly, activity thresholds were established at 800 and 1200 IUJPA respectively, encompassing three risk groups: (i) Healthy Otherwise Normal (<800 IUJPA); (ii) Grey Risk Area (>800 and <1200 IUJPA), and (iii) At Risk group (>1200 IUJPA). Taking into account both baseline and clinical case reports, the Healthy Otherwise Normal group and the At Risk group were mostly homogeneous in nature, comprising a population of normal and cancer patients respectively. The Grey Risk group is heterogeneous, likely reflecting a transitional nature towards a potential early stage of breast disease development. Based on these results, a screening algorithm was developed as the underlining principle for population surveillance encompassing over 30,000 Mexican women. The current screening results have enabled us to objectively prioritize medical attention to approximately 1 in 8 women out of the general population mapped within the At Risk group. Overall, our findings suggest that monitoring Interstron activity units provides a valuable quantitative screening analysis as to selectively streamline the population of women in need of early medical counseling and/or mammography, thereby enhancing both the quality and cost-effectiveness of preventative population surveillance programs targeting breast cancer.

Epidemiologic observations on porcine cysticercosis in a rural community of Michoacan State, Mexico.

The prevalence of and risk factors for Taenia solium infection (cysticercosis) in pigs were studied in a rural community in Michoacan State, Mexico. Visual inspection of the tongues of 216 pigs revealed cysticerci in 14 (6.5%). The prevalence was slightly higher in male (10/105) than female pigs (4/110) (P = 0.06) and increased with age (P less than 0.05). The most important risk factors for infection in pigs were access to human feces at a public washing area (P = 0.004), the presence of an indoor latrine (P = 0.05) and indiscriminate disposal of human feces around the pig owner's household (P less than 0.1). Effective and long-lasting control of the transmission of T. solium from humans to pigs must include measures to deny pigs access to human feces, a change which is likely to be resisted because of the traditional and functional aspects of established pig-rearing practices.

[Sanitary quality of ham eaten in Mexico City]. / Calidad sanitaria del jamón que se consume en la ciudad de México.

Microbiological results of 2,539 hams were analyzed (counts of mesophilic aerobes, Salmonella sp. and S. aureus) at the National Public health Laboratory from 1979 to 1987. In 58.7 percent of the cases the hams were not acceptable for human consumption, due to any of the above mentioned microbiological determinations. The main cause was the finding of high levels of mesophilic aerobes (57.5%), followed by Salmonella sp (4.4%) and S. aureus (0.43%). Raw, cooked and smoked hams presented the highest counts of mesophilic aerobes. Virginia, american style and blade hams presented the most elevated frequencies of Salmonella sp. Baked ham was the one in better sanitary conditions. The conclusion is that the quality of hams in Mexico City is bad.

Diagnostic methods and epidemiologic surveillance of Taenia solium infection.

Taeniasis and cysticercosis caused by Taenia solium, the pork tapeworm, are widespread infections of Latin America, Africa, and Asia. The disease in humans (neurocysticercosis), caused by the cystic larval stages which develop in the central nervous system, is often disabling and sometimes fatal. T. solium infections are endemic in rural and urban areas in some countries that have limited resources to introduce and sustain control programs. To give T. solium control high national priority, the effect of the diseases on health and social care budgets must be accurately measured. Surveys are needed to establish prevalence and geographical distribution of the diseases, to obtain basic epidemiologic data, to learn about transmission, to provide baseline data for the establishment of control measures, and to monitor control measures. Continuing surveys can provide information on changes in prevalence brought about by specific control measures or by changes in the standard of living, education, animal husbandry, and meat processing. Data are not yet available for any endemic-cysticercosis area, and this has hindered efforts to control the disease. There are technical limitations of currently-available methods for diagnosing both taeniasis and cysticercosis in humans in and lower animal hosts. This paper reviews the status and limitations of diagnostic methods and emphasizes the need for further research.

A programme to control taeniasis-cysticercosis (T. solium): experiences in a Mexican village.

A study was carried out in a rural community of the state of Guerrero in order to find ways to control human taeniasis/cysticercosis (Taenia solium). At the beginning of the study the frequency of porcine cysticercosis was established to be around 6.6%. Fecal examination in the human population showed that of 760 persons, 24 were carriers of Taenia sp (3%). Of 440 human sera tested for antibodies against cysticercus cellulosae, 9 showed absorbance values of 0.2 or higher (2.3%). 900 persons received treatment against taeniasis. 400 soil samples and 600 flies were examined for the presence of eggs of Taenioae, all with negative results. Meetings with the adult population were organized to explain the disease and the life cycle of the parasite. Lectures and demonstrations for adults were given at the school for primary and secondary grade children. Special emphasis was given to the need to construct latrines in every home, as it was found that defaecation was practiced mainly in the open, usually at places where pigs had immediate access and ingested the faeces. One year after the initiation of the programme, pigs under the age of 1 year were inspected, to determine whether the cestocide treatment of humans has had an effect on the degree of parasitized pigs and if hygiene had improved. 11% of these animals were found to have cysticerci in their tongue. Two years after the initiation of the programme 78% of the children and 2% of adults answered questions about the lifecycle of the parasite correctly. The results of the trial are discussed and suggestions for future programmes are made.

[Sanitary control of food in Mexico city]. / Control sanitario de alimentos en la ciudad de México.

This work was undertaken as to avoid health risks to tourism in the "XIIth Soccer World Cup, Mexico 86". The above project was carried out through proper quality control of foods, drinking water as well as a definite care of personal hygiene of all those involved in the catering business (132 restaurants were included). The mentioned report informs only of the work of the National Public Health Laboratory in the Sanitary Epidemiological Program. The following products were analyzed: 133 water samples, 272 animated and nonliving surfaces, and 399 foods. Twenty seven percent of water samples were rejected, as well as 85% of the different surfaces and 60% of the food samples. High counts of mesophilic aerobics, followed by coliforms, S. aureus and Salmonella sp., were the principal specimens encountered. Therefore, it was suggested the permanent development of a sanitary epidemiological program.

Taenia solium taeniasis and cysticercosis in a Mexican village.

One hundred and twenty-four persons, nearly the entire population of a rural village in Hidalgo State, were screened for intestinal parasites and clinical or serologic (ELISA) evidence of Taenia solium cysticercosis. Heads of households were questioned about dietary and other practices that might lead to pork tapeworm transmission, and soil samples were examined for helminth eggs. Twenty-five percent of local pigs had cysticerci visible by examination of the undersurface of their tongues. Four persons passed taeniid eggs, 7 were seropositive, and 10 gave medical histories suggestive of neurodysticercosis. Most seropositive persons were not symptomatic and the reverse was also true. The clustered distribution of infected pigs, tapeworm carriers, and persons with serologic or clinical evidence of cysticercosis suggested intrahousehold transmission. Dietary and sanitary practices were generally optimal for transmission of pork tapeworm. No cattle were kept in the village and beef was rarely eaten. This preliminary report attempts to characterize T. solium transmission in communities with endemic disease in rural Mexico and illustrates some of the methodological problems faced by epidemiologists who study this disease.