Helicobacter pylori prevalence among indigenous peoples of South America.

The seroprevalence of Helicobacter pylori among secluded Indian populations of South America was determined to gain insight into the evolutionary history and possible transmission patterns of the organism. Serum samples obtained from 1024 donors in 22 different villages were tested by enzyme-linked immunosorbent assay for immunoglobulin G antibodies, and the results were confirmed by Western blot. The overall seroprevalence was 92%: >80% of children tested positive by 3 years of age, the highest prevalence in populations studied to date. Comparison of H. pylori prevalence with that of herpes simplex virus type 1, which is known to be transmitted orally, demonstrated a linear correlation in their prevalence rates, suggesting that these pathogens share risk factors. However, H. pylori seroprevalence was consistently higher, indicating that additional routes of transmission exist and/or that the organism is more transmissible. Seroprevalence did not correlate with the length of contact with the outside world. These results suggest that H. pylori was indigenous to the South American Indians and was not introduced by contact with outsiders.

The significance of mumps hemagglutinin inhibition titers in normal populations

Mumps hemagglutination-inhibiting antibodies were clearly related to mumps history in diverse normal populations. A decline in titer of about twofold per decade after infection was observed in prospective and retrospective studies. This decline was such that many persons who had had mumps more than 15 years prior to testing had titers that could not be distinguished from non-immune. There was very little variation in titer over one month. Antibodies against four parainfluenza strains were tested for correlation with the discrepancies that were found between mumps serology and history. No correlation was found to suggest that parainfluenza causes a persistent aberration of mumps titer, but transient aberrations may occur.(Summary)

Acute respiratory infections in ambulatory malnourished children: a serological study

We studied the aetiological agents of acute respiratory infections occuring in an ambulatory population of 83 malnourished Jamaican-born children aged 6 to 32 months using serological methods for diagnosis. In 60 percent (38/63) of symptomatic children and in 25 percent (5/20) those without reported disease the following microorganisms were observed: parainfluenza viruses in 15 children, influenza viruses in 12, adenovirus in 10, respiratory syncitial virus in 7 and Mycoplasma pneumoniae in 7 children. The prevalence of the viral infections apparently increased with the severity of malnutrition. (AU)

Acute respiratory infections in ambulatory malnourished children: a serological study - abstract

Fifteen million children under five years of age die each year. Ninety-six per cent of them in "The Third World", and the majority die of acute respiratory infection (ARIs) and/or malnutrition. We therefore studied the aetiological agents of acute respiratory infections occurring in an ambulatory population of 83 malnourished Jamaican-born children, aged 6 to 32 months, using serological methods for the diagnosis. In 60 per cent (38/63) of symptomatic children and in 25 per cent (5/20) of those without reported disease, the following micro-organisms were observed: para influenza viruses in 15 children, influenza viruses in 12, adeno viruses in 10, respiratory syncitial viruses in 7 and Mycoplasma pnuemoniae in 7 children. The prevalence of the viral ARIs increased with the severity of malnutrition. This probably reflects the T-cell immunodeficiency which accompanies protein-energy malnutrition (AU)

Nosocomial and community acquired infections in malnourished Jamaican children - abstract

Infection is a contributing or initiating factor in children with inadequate food intake who develop malnutrition, and malnutrition by virtue of immunosuppression leads to further episodes of infection. In this prospective study, 206 community acquired and 73 nosocomial infections occurring in 50 hospitalised severely malnourished children were investigated. This represented an average of 5.6 episodes of infection per child. Predominant community acquired infections in the 50 children included gastroenteritis (68 percent), otitis media (60 percent), rhinopharyngitis (60 percent), oral candidiasis (46 percent), skin infections (40 percent), pneumonia (28 percent), bacteraemia (24 percent), and bacteriuria (18 percent). The most frequent nosocomial infections were rhinopharyngitis (34 percent), lower respiratory tract infections (24 percent) and septicaemia (18 percent). In those infections where an aetiological agent was identified, Giardia lamblia was the commonest enteric pathogen and Klebsiella sp. were recovered from the majority of urines. Coagulase Negative Staphylococcus was the most frequent aetiological agent of bacteraemia, 12 of the 13 episodes were associated with fever +/- leucocytosis and in six episodes this organism was recovered from two or more blood culture sets. The lack of clinical signs and symptoms, and the atypical presentation in some of the infected malnourished children were attributed to impairment of the acute inflammatory response. Nasal, throat and axillary swabs taken on admission revealed significant colonisation with coliforms and pneumococcus; however, these swabs were not useful as indicators of potentially infective organisms. Two of the four deaths were attributed to infection. The role of Cryptosporidium, an enteric pathogen which is prevalent in immunocompromised hosts, was further investigated. Cryptosporidium was isolated from the stools of 19.5 percent (15/77) malnourished children compared to 2.4 percent (10/436) well-nourished children, who were more likely to present with fever, vomiting, prolonged diarrhoea and dehydration. Community acquired non-bacterial respiratory tract infections were further investigated from paired sera in 83 moderately malnourished children. In 60 percent of the children with a history of respiratory tract disease and 25 percent of those without reported disease, a specific non-bacterial infection was diagnosed. Multiple aetiological agents were identified in 6 of the 42 chidren with respiratory disease. The most common micro-organisms observed were: Para-influenza 1,2 or 3 (in 15 children), Influenza H1N1, H2N3 or "B" in 12, Adenovirus in 10, Respiratory Syncitial Virus in 7 and Mycoplasma Pneumoniae in 6 children. These three studies report a high prevalence of common and unusual infections, especially Cryptosporidium enteritis and Coagulase Negative Staphylococcus bacteraemia, occurring in these immunocompromised children. Diagnosis of infection requires a high index of suspicion and a comprehensive screening system (AU)

Maternal and cord serum titres as predictors of the age of measles susceptibility and vaccine responsiveness in Jamaica - abstract

Wide geographic variation in the age of measles susceptibility and vaccine responsiveness provides good reason for differences in the recommended age of immunization, varying from six months in some African countries to fifteen months in the United States. We have developed a method for determining the optimal age of measles immunization, without performing formal tests of vaccine responsiveness in children of those age groups known to be suboptimal for immunization. We have measured measles neutralizing the haemagglutination-inhibiting antibody titres in Jamaica maternal and umbilical cord sera, and in infant sera taken at age five to seven months. The mean maternal neutralizing antibody titre was 7.7 log 2 units; it was concentrated to 8.2 log 2 units across the placenta. These values are the highest obtained for developing countries. The estimated half-life of passively acquired maternal measles antibody was 43 days as measured by the neutralization test and 48 days by the haemagglutination test. These half-lives were similar to those obtained from smaller groups of infants in Taiwan and New Haven, United States. The optimal age for mass measles vaccination was determined by statistical methods to be 10 to 11 months in Jamaica. In other populations, the same methodology could be used to determine the optimal ages for measles immunization (AU)

Durability of passive measles antibody in Jamaican children

Measles antibody titres were determined by haemagglutination inhibition and by neutralization in 221 sets of serum collected from delivering mothers, umbilical cords, and infants when about six months of age. Radio-immunoassay was also used to measure antibody in 120 sera. Total IgG concentration was determined in the infant sera. All mothers had measles antibody and the mean titre was high. At the time of birth, measles antibody had been further concentrated in the infant. Nevertheless, many children lost protective titres before six months of age. The rate of loss was correlated with the infant's total serum lgG so that high lgG levels at six months correlated with rapid loss of measles-specific antibody. It is suggested that in homes where sanitation is poor, antibody is made to many agents as an early age. To maintain physiological balance, homeostatic mechanisms then increase the rate of catabolism of all lgG, including that passively acquired. In keeping with its stage of sanitary development, vaccination in Jamaica can profitably be given earlier than in the United States, but it must be later than in many African countries. (AU)

GC polymorphism investigated by isoelectric focusing: a study in south american indians

Os plasmas de um total de 488 indivíduos pertencentes a cinco populaçöes indígenas sul-americanas foram investigados, por meio de isoeletrofocalizaçäo, quanto ao sistema GC, e os resultados obtidos foram comparados aos descritos para onze outras tribos ameríndias. A um nível de 0,15 dissimilaridade genética foram observados quatro agrupamentos, näo tendo sido detectada uma associaçäo clara entre as freqüências alélicas neste sistema e a quantidade de radiaçäo solar

Infecçäo, mortalidade e populaçöes indígenas: homogeneidade biológica como possível razäo para tantas mortes / Infection, mortality and Indian populations: biological homogeneity as a probable reason for so many deaths

Discute as várias causas que provocaram a drástica reduçäo populacional em grupos indígenas. Adianta que as doenças infecciosas foram o fator biológico mais importante. Argumenta também que a principal razäo das doenças infecciosas terem tido tamanho impacto näo se deveu necessariamente à ausência de genes específicos relacionados à capacidade de resposta imune, mas ao fato das populaçöes ameríndias serem biologicamente muito homogêneas do ponto de vista genético.