Measles aerosol vaccination.

Measles ranks fifth among the five major childhood conditions which are responsible for 21% of all deaths in low and middle-income countries. Measles immunization is considered the most cost-effective public health intervention in the world. In recent years, there has been a critical need to identify alternative routes of measles immunization, which are rapid, reliable, cost-effective, needle-free, and suitable for use in mass campaigns. Aerosol administration of measles vaccines in mass campaigns was first proposed by Dr. Albert Sabin. We review the different clinical trials that have been conducted using the classic Mexican device as well as issues regarding vaccine strain, presentation, and manufacturer. Results of clinical trials indicate that the method is safe and immunogenic in infants and school age children. The viral inoculum will probably need to be increased when administered to infants. From the logistical point of view, the use of the aerosol method has not been evaluated in routine immunization although feasibility of its routine implementation was proved in mass campaigns in Mexico. Cost savings will probably be demonstrated. As to licensure, its compliance with the appropriate international regulatory requirements for medical aerosol delivery devices is in process.

Cholesterol levels and prevalence of hypercholesterolemia in a Mexican adult population.

In Mexico, the incidence and prevalence of coronary heart disease (CHD) has increased over the past three decades and has become the leading cause of death in the country. Hypercholesterolemia is a major risk factor for coronary atherosclerosis and most developed countries currently have public health strategies that attempt to reduce the level of cholesterol. In order to determine the mean total cholesterol values and the prevalence of hypercholesterolemia, an epidemiologic survey was carried out in a representative national population sample that included men and women aged 1 to 98 years. In this report, we present the findings in all individuals older than 20 years (n = 33,558). Considering the country as a whole, the mean serum total cholesterol (TC) was 4.80 +/- 1.16 mmol/l, the prevalence of borderline hypercholesterolemia (TC between 5.17 and 6.20 mmol/l) was 22.8% and the prevalence of high risk hypercholesterolemia (TC > or = 6.20 mmol/l) was 10.6%. This cross sectional study demonstrated the existence of significant geographic differences in serum TC, with mean state values ranging from 4.43 +/- 1.05 mmol/l in the south to 5.48 +/- 1.36 mmol/l in the north. The prevalence of high risk hypercholesterolemia was as high as 24.8% in Baja California Norte and as low as 4.0% in the state of Guerrero. These large differences in mean TC values are probably diet related and reinforce the need to carry out prospective and intervention trials related to CHD and its risk factors.

[The HIV/AIDS epidemic and women in Mexico]. / La epidemia de VIH/SIDA y la mujer en México.

This study presents an analysis of AIDS cases and seroprevalence of HIV infection among Mexican women, from the onset of the epidemic through June 1994, as well as the analysis of the social and cultural factors that put women in a powerless situation regarding the adoption of preventive measures. Since 1985, when the first AIDS cases among women were reported in Mexico and until June 1, 1994, a total of 2,767 cases have been reported, representing 14.8% of the total number of cases. The first cases of AIDS among women were associated to infected blood transfusions; however, in 1986, heterosexually transmitted cases began to appear. Currently, only 35% of newly reported AIDS cases are associated to blood transfusions while 64% of them are related to heterosexual transmission. In fact, two epidemics are evident: one transmitted through blood, showing a downward trend (duplication time 45 months), and a second one, heterosexually transmitted, increasing twice as fast (duplication time 27 months). The latter is expected to dominate AIDS epidemiology among women in the future. In general, women are more vulnerable to HIV/AIDS biologically, but also socially and culturally. Women's economic, social and cultural subordination to their sexual partners results in a situation that makes it difficult for them to assess their infection risk and even more, to negotiate taking preventive measures. This situation is even more disadvantageous to rural women and, together with the recent trend of the AIDS epidemic to ruralization and with internal and international migration (temporary work force migration to the USA), can result in deep demographic and social effects. We conclude that it is necessary to work on the design and assessment of preventive measures under women's control, that empower them to protect themselves even without their partner's awareness. Also, it is necessary to promote sexual education among young heterosexual couples on how to talk about sexual issues and negotiate the use of preventive measure according to their actual sexual practices.

[Tuberculosis and AIDS in Mexico]. / Tuberculosis y SIDA en México.

Tuberculosis (TB) still is an important health problem in Mexico. According to reported figures, an excess in the number of cases has occurred during recent years, mainly among young adults of both sexes. The present estimated rate of TB is 51.7 cases/100,000 inhabitants. This is the most frequent endemic infection among AIDS patients, ranking third among infectious diseases after candidiasis and P. carinii pneumoniae. A total of 8.3% of the 19,352 AIDS cases notified to July 1994, presented TB as the initial manifestation. According to sentinel surveillance carried out since 1990 in 17 states, HIV seroprevalence among TB patients has been 3.1% (0-6.5%) in males and 1.0% (0-2.3%) in females. Results of epidemiologic research in the field of TB prevention and characteristics of drug sensitivity of strains of M. tuberculosis isolated from HIV/AIDS patients are also described. Finally, perspectives of TB prevention and control are discussed.

[The strategy for preventing HIV/AIDS transmission via the blood and its derivatives in Mexico]. / La estrategia de prevención de la transmisión del VIH/SIDA a través de la sangre y sus derivados en México.

This study presents blood-associated AIDS epidemic trends in Mexico, including cases due to blood transfusions, cases in professional blood donors and hemophiliacs. We present also an overview of preventive measures--both legal and educative--undertaken to prevent this type of transmission and its effects on the epidemic. The first blood-associated AIDS cases in Mexico were reported in 1985, since then and up to July 1, 1994 a total of 1,728 adult cases and 116 pediatric cases have been reported (12.3% and 25% of the total cases, respectively). As in many other parts in the world, in Mexico women were markedly affected by this form of transmission; the women to men morbidity ratio is 1.35. Another group particularly affected by AIDS in Mexico are professional blood donors, who were infected because of improper management and recycling of blood transfusion centers bank materials such as plasmapheresis sets, in some blood transfusion centers in our country. Blood screening is mandatory for all blood donors in Mexico since May, 1986. A year later blood commercialization was banned because of the extremely high HIV infection prevalences found in some professional blood donors (7.2%). Since that time a whole set of preventive measures has been implemented in our country, including blood quality and safety control as well as educative interventions. Results of these measures began to become evident by the end of 1991, when newly reported blood associated AIDS cases started to decrease, as opposed to their continuous growth seen in previous years. Up to July 1, 1994 we estimate that a total of 2,750 AIDS cases have been prevented through these measures, recovering an average of 36 years of potential life for each of them. Although blood transmission preventive measures have rendered significant achievements, we still have to face some very complex challenges such as potential ruralization of the epidemic and its impact on HIV infection prevalences among potential blood donors and therefore the need to ensure blood screening in rural areas.

Epidemiology of AIDS and tuberculosis.

This article reviews literature on the epidemiology, pathogenicity, and control of HIV and Mycobacterium tuberculosis coinfection. Regarding pathogenicity, immune system deterioration makes HIV-infected people more likely to develop active tuberculosis on primary or secondary exposure to the bacillus or to suffer reactivation of latent infections, and to experience considerably higher rates of extrapulmonary manifestations, relapses, and death. Regarding epidemiology, as of 1990 there were an estimated 3 million people coinfected with HIV and M. tuberculosis, with some 300,000 active tuberculosis cases and 120,000-150,000 tuberculosis deaths occurring annually among those coinfected. Over 500,000 coinfected people are thought to reside in the Americas, over 400,000 of them in Latin America. In general, the impact of coinfection is evident. Relatively high and increasing prevalences of HIV infection have been detected among tuberculosis patients around the world, and tuberculosis has become a frequent complication of AIDS cases. Moreover, there is no longer any doubt that coinfection obstructs tuberculosis prevention and control. Among other things, it affects BCG vaccination policies, suggests the need to administer preventive chemoprophylaxis to HIV-infected individuals at high risk of harboring or contracting tuberculosis infections, and complicates both detection and treatment of active tuberculosis cases. The recent proliferation of M. tuberculosis strains resistant to multiple drugs, most notably in the United States, compounds the problem. Tuberculosis prevention and control are still technically and economically feasible. However, more must be done to establish surveillance programs with laboratory support. More research is needed to determine what case prevention measures are best-suited to current circumstances and the HIV/AIDS presence. More effective preventive treatment regimens that are well tolerated, well complied with, and do not pose the risk of multiresistance need to be devised. More health workers need to be trained to suspect tuberculosis and to conduct timely and appropriate tests confirming this diagnosis. And finally, more must be done to standardize the types and durations of the various curative treatment regimens employed.

[Anemia in women of reproductive age. The results of a national probability survey]. / Anemia en mujeres de edad reproductiva. Resultados de una encuesta probabilística nacional.

Iron deficiency is one of the most prevalent forms of malnutrition which is clinically known as anemia. Functional consequences of anemia include impairment of cardiovascular performance, limitation in productivity, higher incidence of low birth weight and premature delivery, and increased maternal mortality. This paper presents a descriptive analysis of anemia in women of reproductive age in Mexico. Data were collected by the Ministry of Health through a National Nutrition Survey in 1988, which draw a representative sample from four regions: North, Center, South and Federal District. Anemia was more prevalent in pregnant (18.17%) than in non-pregnant women (15.38%). Those women living in predominantly indigenous communities had higher prevalence of anemia (24.02%) than non-indigenous women (14.67%). Anemia was more prevalent in urban areas (15.54%) than in rural (13.56%). Mean +/- standard deviation values for hemoglobin were lower in pregnant women (12.5 +/- 1.6 g/dL) than in non-pregnant ones (13.7 +/- 1.6 g/dL). Consistently, the Northern and Southern regions were worse off than the Center and the Federal District. These data indicate that anemia is a public health problem in Mexico. The functional consequences of this deficiency justify interventions to treat and prevent it.

[Stunting and emaciation in children under 5 in distinct regions and strata in Mexico]. / Déficit de talla y emaciación en menores de cinco años en distintas regiones y estratos en México.

Data from a National Nutrition Survey conducted in 1988 in a probability sample of 13,236 households and 17,426 children under five, representative at the national level and for four regions (North, Center, South, and Mexico City), were analyzed. Risks for wasting and stunting and odds ratios were obtained by region, by district according to proportion of indigenous population and by level of urbanization, by level of education of both parents, by gender, and by various combinations of the former strata. A high risk of stunting and a low risk of wasting were found. The risk of stunting is greater in predominantly indigenous and rural districts, in the South and Center, and in families of mothers with low education and poor housing conditions. The results can be used for food and nutrition policy planning and for targeting nutrition intervention programs.

[Private medicine in Mexico: the results of the National Census of Private Hospital Units]. / La medicina privada en México: resultados del Censo Nacional de Unidades Hospitalarias Privadas.

A census of private health establishments was carried out by the Secretary of Health, in order to quantify its resources and to describe their geographical distribution. The census, conducted in 1994, was limited to private units which offered hospitalization services, and the reference period was the previous year. Results showed that there are 2,723 private hospitalization units in Mexico, and nearly a half of the units are concentrated in the Federal District, and the states of Mexico, Guanajuato, Michoacán, Baja California and Veracruz. The number of private hospitalization beds registered in the country are 33,937, these figures indicate that private medicine is the main hospital care provider in the national health system. Similar results were obtained regarding other material and human resources. It is important to stress the need for further research regarding the role of private medicine in Mexico, including aspects related to the quality of the services being provided.

[Mexican phenotype and genotype Vibrio cholerae 01]. / Vibrio cholerae 01 fenotipos y genotipos México.

This paper presents the phenotypical and genotypical characterization of 26922 Vibrio cholerae 01 strains isolated in Mexico from 1991 to 1993. All strains isolated were El Tor biovar. Strains were sensitive to antibiotics excluding furazolidone, streptomycin and sulfisoxasole to which we found resistance in 97% and we are using this characteristic as epidemiological markers. We detected a marked change in frequency of Inaba serotype from 1991, when it was dominant, with 99.5%, until 1992 when Ogawa serotype turned to be dominant with 95% of isolates. All Vibrio cholerae 01 strains, except one Ogawa strain, were to igenic, and V. choleraeno 01 were not toxigenic by ELISA, PCR and cell culture tests. Dominant ribotype was 5, but we found some strains with 6a pattern and two with ribotype 12. We are searching for ribotype 2 among hemolytic strains in order to learn if there is any relation to Gulf Coast strains prevalent in the USA, but until now we have not found any V. cholerae ribotype 2 in our isolates. Even if rapid tests are recommended for immediate diagnosis of cholera, it is necessary to continue bacterial isolation in order to have strains for phenotyping and genotyping studies that may support epidemiological analysis.

[Identification of Vibrio cholerae O1 by flow cytometry]. / Identificación de Vibrio cholerae O1 por citometría de flujo.

A total of 72 peptonated water samples suspected of carrying Vibrio cholerae were assessed by laser flow cytometry (LFC) and compared with positive culture. We used a direct fluorescence technique using polyclonal (PolAb) and monoclonal antibodies (MoAb) conjugated to fluorescein. The PolAb were able to detect 33 positive samples. A clear difference among the 20 positive samples was found with only three V. cholerae O1 false negatives when MoAb were used whereas all 13 V. cholerae Non O1 samples were detected. The correlation index comparing control autofluorescence with peptonated water samples show a R = 0.69, versus 0.96 with pure V. cholerae O1 strains. Our data suggest that the LFC technique is able to recognize V. cholerae O1 from a mixture of microorganisms with high sensitivity and specificity in a few hours.

[Epidemiology and etiology of infectious diarrheas. The case of Mexico]. / Epidemiología y etiología de las diarreas infecciosas. El caso de México.

Gastrointestinal infections represent a health problem. It is estimated that 1647 million cases of diarrhea and 3.2 million deaths due to this cause occur among children less than five years of age per year. Those belonging to this age group have 15 times more risk of dying because of diarrhea. Cases of liquid acute diarrhea with blood represent 80% of cases, diarrhea with blood represent 10%. Most frequent causes of liquid diarrhea are enterotoxigenic Escherichia coli and rotaviruses and most frequent causes of bloody diarrhea are Shigella, E. coli (EHEC and EPEC). Campylobacter jejuni and Entamoeba histolytica. Annually 15,000 cases of typhoid fever are reported that continue being a public health problem. A negative correlation has been observed between the use of oral rehydration and infant mortality due to diarrhea. After prevention and control measures for cholera, a decrease in morbidity and mortality due to diarrhea has been observed. However, to reduce mortality due to this cause, it is necessary to treat the cases of acute dysentery and persistent diarrhea as well as to increase coverage of health care, to standardize the studies of etiology of diarrhea in Mexico, to establish surveillance centers for the study of diarrhea that give information on the distribution, frequency and trends of microbial agents and to achieve standardized microbiological and parasitological studies of etiology of diarrhea that support public health interventions as vaccination and selective administration of antibiotics.

[Education of Mexican health personnel on AIDS]. / Educación del personal de salud de México sobre el SIDA.

We describe the epidemiology of AIDS as it pertains to health workers in Mexico. Of the 12,151 cases notified in adults up until 1993, 2.9% occurred among such workers. Two cases of occupational transmission have been documented. Seroprevalence surveys have shown an infection rate of less than 0.1%. Nonetheless, the frequency with which hepatitis B viral markers are present (11.8% of anti-HBs antibody carriers and 2% of anti-HBsAg antibody carriers) points to the fact that mechanisms for the transmission of both types of viruses are at work. Surveys conducted among health workers to explore their knowledge and attitudes on the subject of AIDS indicate that they share many false notions about the disease and that they stigmatize its victims. Educational campaigns have improved knowledge about the illness but have not modified people's attitudes significantly. Holding workshops has proved to be the most useful strategy for attitude modification. We describe a few strategies that may be useful for changing negative attitudes among health personnel. When calculating the frequency with which biosafety measures are implemented, it has been noted that their application is erratic. Epidemiologic studies have confirmed the existence of an association between the time of occupational exposure and the presence of hepatitis B viral markers. Many people reject adopting certain measures, such as anti-hepatitis vaccination. Finally, we analyze the need for continuous training and supplies if increased biosafety measures are to be adopted.

Seroepidemiology of amebiasis in Mexico.

The presence of serum antibodies to Entamoeba histolytica was detected by indirect hemagglutination in a representative sample of the 32 federal entities of the Mexican Republic. This study was designed to include biologic, geographic, social, economic, and educational variables. The total percentage of positive sera was 8.41%. Seroprevalence varied with geographic zones, with the South Central, South Pacific, and Yucatan Peninsula areas showing the highest values (> or = 9%), and the North, Northeast, and Gulf of Mexico areas showing the lowest values (< or = 8.0%). Seroprevalence of anti-E. histolytica antibodies seemed to increase from the northern regions to the southern areas of Mexico. These results indicated that amebiasis is endemic in the Mexican Republic, with areas of high seroprevalence not related to climatic conditions. Exposure to infectious contact with E. histolytica occurred at all ages, with a higher frequency at school age.

Cholesterol levels and prevalence of hypercholesterolemia in Mexican children and teenagers.

In Mexico, the incidence and prevalence of coronary heart disease has increased over the past three decades and has become the leading cause of death in some areas of the country. Hypercholesterolemia (HC) is a major risk factor for coronary atherosclerosis and most developed countries currently have public health strategies that attempt to reduce the level of cholesterol. In order to learn the mean total cholesterol values and the prevalence of HC, an epidemiologic survey was carried out in a representative population sample that included men and women aged 1 to 98 years, across the nation. In this report, we present the findings in children and teenagers of both sexes (n = 34369). Considering the country as a whole, the mean serum TC was 147 +/- 35 mg/dl, the prevalence of borderline hypercholesterolemia (TC between 170 and 199 mg/dl) was 14.7% and the prevalence of high risk hypercholesterolemia (TC > or = 200 mg/dl) was 6.7%. This cross sectional study demonstrated the existence of significant geographic differences in serum TC, with mean state values ranging from 133 mg/dl in the south to 164 mg/dl in the north. The prevalences of high risk hypercholesterolemia was as high as 18.2% in Baja California Norte and as low as 2.5% in the state of Morelos. These geographic differences in total cholesterol and prevalence of hypercholesterolemia were already present at one year of age and persisted throughout childhood and adolescence.

[Door-to-door vaccination as a strategy for eradication of poliomyelitis]. / La vacunación casa a casa como estrategia de erradicación de la poliomielitis.

Due to persistence of poliomyelitis cases in the Pacific Coast of Mexico and particularly in the state of Sinaloa, a house to house vaccination strategy named "Sinaloa Operation" was carried out in 100% of the territory of this state. Sinaloa was divided in small geographical and statistical unit area (AGEB). Simultaneously, teams of nurse carried out a population census of children under five years old and pregnant women. Nurses vaccinated the children with Sabin trivalent vaccine in undiscriminating form. These activities were made in three phases. In the last phase (February 1991) 301, 441 Sabin vaccine doses were administered. This figure represents an extension of the vaccination coverage to the children of the seasonal migrant workers from other parts of the country. As a result of this programme. Sinaloa has not had any other polio case since two years ago.