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Child poverty in South America: reflections on its magnitude, and the basic-need developmental approach. A retrospect on the International Year of the Child.

Extreme economic poverty in children with its adverse consequences on their mental and physical growth is becoming an increasing concern of governments in South America. There is now a search for effective intervention strategies to alleviate these problems as they are also a bottleneck for national development. Some of these programs are likely to be defined as fitting within the general theoretical framework of the basic-need approach to development. This paper postulates that intervention programs (e.g., nutrition, health and education) directed to economically deprived children will not be successful and are not representative of the basic-needs approach unless they also attend to the broader economic and social needs of families and communities. Although child-directed programs have proven to be moderately successful they do not eliminate the mental and physical growth differences between children determined by economic inequality.

Adolescent↗

Bacterial resistance in South America.

The emergence of resistant strains of bacteria is directly related to the selection of chemotherapeutic agents, and the character of the resistance changes with changes in use-frequency of the various antibiotics. In recent years with increasing use of beta-lactam antibiotics, there has been an increased incidence of microorganisms that are resistant by virtue of their ability to produce beta-lactamase enzymes which destroy the beta-lactam antibiotics. The development of beta-lactamase inhibitors which may be used in combination with the beta-lactam antibiotics has been a significant advance for the therapy of gynecologic infections in South America.

Bacterial Infections↗

Epidemiology and control of bovine ostertagiasis in South America.

Gastrointestinal parasitism has been recognized by practitioners as the most common disease in beef cattle, mainly in weaning calves and fattening steers. Among the different genera, Ostertagia ostertagi is the predominant parasite in the temperate climate, in which the major beef and dairy cattle area of South America is situated. Outbreaks of Type I ostertagiasis are usually seen after weaning time (autumn-winter) when larvae counts are high and food availability is low. The development of the disease is rapidly established and 15-30 kg are lost in 30-50 days. Epidemiological studies have demonstrated a fast evolution of parasite eggs to larvae (L3) in summer (1 week or less), evolution being 30-45 days during winter. Inhibition O. ostertagi occurs during spring (September-December) and development resumes in late summer and early autumn. The production effect is seen as a significant reduction in body weight gain and occasionally clinical Type II ostertagiasis appears. A similar epidemiological pattern of inhibition of Ostertagia sp. has been recorded in Uruguay and temperate areas in southern Brazil.

Animals↗

Genetic variability and chromosome-length polymorphisms of the witches' broom pathogen Crinipellis perniciosa from various plant hosts in South America.

Crinipellis perniciosa has been classified into at least four known biotypes associated with members of unrelated plant families. In this study, genetic variability is shown for 27 C (Cacao), 4 S (Solanum), and 7 L biotype (Liana) isolates of C. perniciosa collected from different regions of Brazil and South America. The objective was to investigate the genetic variability of the pathogen in the cacao-producing region of Bahia, Brazil, and elsewhere, through microsatellite analysis, and attempt to identify possible correlations between host specificity and electrophoretic karyotypes. The PCR-banding patterns were found to vary both within and between the different biotypes, and a correlation was established between the PCR-banding patterns and the chromosomal-banding patterns of each isolate. Microsatellite and chromosomal patterns among all of the L and S biotype isolates were distinctly different from the C biotypes analysed. A higher degree of genetic and chromosomal variability was found among C biotype isolates from the Amazon in comparison with C biotype isolates from Bahia, which seems to be comprised of only two main genotypes. This finding has important implications to the current cacao-breeding programme in Brazil.

Agaricales↗

Latitudinal variation for two enzyme loci and an inversion polymorphism in Drosophila melanogaster from Central and South America.

Many organisms show latitudinal variation for various genetically determined traits. Such clines may involve neutral variation and originate from historical events or their maintenance may be explained by selection. For Drosophila melanogaster, latitudinal variation for allozymes, inversions, and quantitative traits has been found on several continents. We sampled D. melanogaster populations in Panama and along a transect of 40 latitudinal degrees on the west coast of South America. Negative correlations with latitude were found for AdhS and alpha GpdhF allele frequencies and for the frequency of the cosmopolitan inversion In(2L)t in AdhS alpha GpdhF chromosomes. A positive correlation existed between wing length and latitude. Significant correlations were found between these traits and climatic variables like temperature and rainfall. The observed clines show considerable resemblance to those found on other continents. Gametic disequilibrium between AdhS and alpha GpdhF occurred predominantly at higher latitudes and was caused by the presence of In(2L)t. The reasons for the clinal distributions are discussed and it is argued that selection is the most likely explanation. However, the exact nature of the selective force and the interactions of allozymes with each other and with In(2L)t are complex and not fully understood. In tropical regions In(2L)t-containing genotypes have higher fitness than ST/ST and Adh and alpha Gpdh hitchhike with the inversion, but there is also evidence for balancing selection at the Adh locus.

Alcohol Dehydrogenase↗

Genetic variability of hepatitis A virus in South America reveals heterogeneity and co-circulation during epidemic outbreaks.

Genetic analysis of selected genome regions of hepatitis A virus (HAV) suggested that distinct genotypes of HAV could be found in different geographical regions. In order to gain insight into the genetic variability and mode of evolution of HAV in South America, an analysis was performed of sequence data obtained from the VP1 amino terminus and the VP1/2A region of HAV strains isolated over a short period of time in Uruguay, Argentina and Chile. Sequences obtained from 22 distinct HAV isolates were compared with published sequences from 21 different strains isolated all over the world. Phylogenetic analysis revealed that all strains isolated belong to a unique sub-genotype (IA). Strains isolated during an outbreak period showed a higher degree of heterogeneity than anticipated previously and the co-circulation of different isolates. The genetic variability among strains isolated in this region seems to be higher in comparison with strains isolated in other regions of the world.

Disease Outbreaks↗

Bronchoscopy in children in South America.

Bronchoscopy is an important tool in the study of the airway. Diagnostic and therapeutic uses are well described in the literature and standardisation of the technique is well defined. Most relevant publications on bronchoscopy come from Europe and the United States, and in some countries they are used as guidelines for local hospitals. In spite of the limited experience published from South America, and the scarcity of financial resources, important information and research pathways have been developed in paediatric bronchoscopy. The information in this review was compiled from local publications, case reports, review articles, brief reports and congress presentations to provide an overview and share the experience about bronchoscopy in South American children.

Bronchoscopy↗

[The role of reference laboratories in animal health programmes in South America].

The contribution of the Panamerican Foot and Mouth Disease (FMD) Centre (PANAFTOSA), as an OIE (World organisation for animal health) regional reference laboratory for the diagnosis of FMD and vesicular stomatitis, and for the control of the FMD vaccine, has been of fundamental importance to the development, implementation and harmonisation of modern laboratory procedures in South America. The significance of the work conducted by PANAFTOSA is particularly obvious when one considers the two pillars on which eradication programmes are based, namely: a well-structured regional laboratory network, and the creation of a system which allows technology and new developments to be transferred to Member Countries as quickly and efficiently as possible. Over the past decade, PANAFTOSA has kept pace with the changing epidemiological situation on the continent, and with developments in the international political and economical situation. This has involved the strengthening of quality policies, and the elaboration and implementation of diagnostic tools that make for more thorough epidemiological analyses. The integration of PANAFTOSA into the network of national laboratories and its cooperation with technical and scientific institutes, universities and the private sector means that local needs can be met, thanks to the design and rapid implementation of methodological tools which are validated using internationally accepted criteria. This collaboration, which ensures harmonisation of laboratory tests and enhances the quality of national Veterinary Services, serves to promote greater equity, a prerequisite for regional eradication strategies and this in turn, helps to increase competitiveness in the region.

Animal Welfare↗

Arthropod and helminth parasites of the wild guinea pig, Cavia aperea, from the Andes and the cordillera in Peru, South America.

As part of an ongoing research project concerning the diversity and distribution of parasites of Caviidae in South America, 143 wild guinea pigs (Cavia aperea) were collected from 3 localities in the Andean Highlands of Peru. Samples were collected between November 1996 and May 1999 and included representatives of arthropods, nematodes, and trematodes. Seven species of arthropods: Leptopsylla segnis (27.3%), Tiamastus cavicola (6.9%), Gliricola porcelli (55.2%), Hoplopleura alata (6.9%), Polyplax spinulosa (12.6%), Myobia musculi (1.4%), and Eutrombicula bryanti (49.6%); 4 species of nematodes: Capillaria hepatica (6.9%), Graphidioides mazzai (18.8%), Trichuris gracilis (3.5%), and Paraspirudera uncinata (37%); and a single trematode, Fasciola hepatica (4.2%), were identified.

Animals↗

[Distribution of PRA patterns of clinical isolates of the Mycobacterium avium complex from Spain and South America].

Mycobacterium avium complex (MAC) infections are the most frequent systemic infections associated with advanced AIDS. DNA probes for accurate identification of mycobacteria are available but are very expensive in many Latin American settings. Consequently, most Latin American diagnostic laboratories employ inaccurate and outdated tests for mycobacteria identification. Therefore, PCR restriction analysis (PRA) of the hsp65 gene was evaluated for the identification of 163 MAC human isolates originated from Spain and South America. The predominant PRA type in each country was: M. avium type I in Argentina (23/42, 55%) and Brazil (48/72, 67%), M. avium type II in Spain (18/26, 69%) and M. avium type III in Colombia (10/23, 43%). The Colombia frequency is noteworthy, since the PRA type III was quite infrequent in the other three countries. Furthermore, its presence has not been reported outside the Americas. The advantages and disadvantages of PRA in diagnostic mycobacteriology are discussed.

Humans↗

Evolution of a unique Plasmodium falciparum chloroquine-resistance phenotype in association with pfcrt polymorphism in Papua New Guinea and South America.

The mechanistic basis for chloroquine resistance (CQR) in Plasmodium falciparum recently has been linked to the polymorphic gene pfcrt. Alleles associated with CQR in natural parasite isolates harbor threonine (T), as opposed to lysine (K) at amino acid 76. P. falciparum CQR strains of African and Southeast Asian origin carry pfcrt alleles encoding an amino acid haplotype of CVIET (residues 72-76), whereas most South American CQR strains studied carry an allele encoding an SVMNT haplotype; chloroquine-sensitive strains from malarious regions around the world carry a CVMNK haplotype. Upon investigating the origin of pfcrt alleles in Papua New Guinean (PNG) P. falciparum we found either the chloroquine-sensitive-associated CVMNK or CQR-associated SVMNT haplotypes previously seen in Brazilian isolates. Remarkably we did not find the CVIET haplotype observed in CQR strains from Southeast Asian regions more proximal to PNG. Further we found a previously undescribed CQR phenotype to be associated with the SVMNT haplotype from PNG and South America. This CQR phenotype is significantly less responsive to verapamil chemosensitization compared with the effect associated with the CVIET haplotype. Consistent with this, we observed that verapamil treatment of P. falciparum isolates carrying pfcrt SVMNT is associated with an attenuated increase in digestive vacuole pH relative to CVIET pfcrt-carrying isolates. These data suggest a key role for pH-dependent changes in hematin receptor concentration in the P. falciparum CQR mechanism. Our findings also suggest that P. falciparum CQR has arisen through multiple evolutionary pathways associated with pfcrt K76T.

ATP-Binding Cassette Transporters↗

Emergence of a new epidemic/epizootic Venezuelan equine encephalitis virus in South America.

One of the most important questions in arbovirology concerns the origin of epidemic Venezuelan equine encephalitis (VEE) viruses; these viruses caused periodic, extensive epidemics/epizootics in the Americas from 1938-1973 (reaching the United States in 1971) but had recently been presumed extinct. We have documented the 1992 emergence of a new epidemic/epizootic VEE virus in Venezuela. Phylogenetic analysis of strains isolated during two outbreaks indicated that the new epidemic/epizootic virus(es) evolved recently from an enzootic VEE virus in northern South America. These results suggest continued emergence of epizootic VEE viruses; surveillance of enzootic viruses and routine vaccination of equines should therefore be resumed.

Animals↗

Epidemiology of trichinellosis in Mexico, Central and South America.

Trichinella species are widely distributed throughout the world and are found in a large number of carnivorous animals, humans and incidental hosts. The data presented in this review show that Trichinella infection has been reported in both humans and animals in Mexico, Argentina and Chile since the end of the 19th century, and more recently in Bolivia. This parasitic infection is still a public health problem in countries such as Argentina and Chile. Although efforts have focused on the control and prevention of trichinellosis in these countries, there were still human cases and outbreaks of trichinellosis reported. Diagnosis of infection in animals such as pigs still includes, in many endemic areas, the use of trichinoscopy. In Argentina, however, artificial digestion has been recently introduced in slaughterhouses to detect Trichinella infection in pigs. In some endemic areas in Mexico, the use of serological assays for human trichinellosis and pig infections have resulted in improved detection. Most of the outbreaks of human trichinellosis in Mexico, Argentina and Chile have occurred as a result of the consumption of undercooked pork or pork products from animals raised under poor hygienic conditions and which are clandestinely slaughtered. In several studies, rats, dogs and cats have been found to be infected with Trichinella and may be considered a risk for transmission of the infection to pigs or other animals intended for human consumption. Another potential source of transmission of Trichinella to humans is horsemeat; however, information related to horse trichinellosis in Latin-American countries is scarce. In most cases the etiological agent of human trichinellosis in Central and South America has been reported to be Trichinella spiralis; however, only in a few cases has the parasite species been properly identified. Based on the reports available, it is clear that there is a need to carry out better controlled epidemiological studies to determine the true prevalence of the infection in this region of the world. Also, more sensitive methods of diagnosis and improvements in conditions for pig production as well as better sanitary inspection systems, are needed for controlling and preventing transmission of trichinellosis in these countries.

Animal Husbandry↗

Influence of mate drinking, hot beverages and diet on esophageal cancer risk in South America.

To estimate the effects of consuming hot beverages, including mate (an infusion of the herb Ilex paraguayensis), tea, coffee and coffee with milk, and other food items on esophageal cancer risk, we analyzed data from 830 cases and 1,779 controls participating in a series of 5 hospital-based case-control studies of squamous-cell carcinoma of the esophagus conducted in high-risk areas of South America. After adjusting for the strong effects of tobacco and alcohol consumption, both heavy mate drinking (>1 l/day) and self-reported very hot mate drinking were significantly associated with esophageal cancer risk in men and women. The magnitude and strength of the association for mate amount and, to a lesser extent, mate temperature were higher for women than men. The joint effects of mate amount and mate temperature were more than multiplicative, following a statistically significant synergistic interaction (p = 0.02) which was particularly evident among heavy drinkers (>1.50 l/day) of very hot mate (odds ratio = 4.14, 95% confidence interval: 2.24-7.67) compared to light drinkers (<0.50 l/day) of cold/warm/hot mate. Consumption of other very hot beverages, such as tea and coffee with milk but not coffee alone, was also significantly associated with an increased risk, in the 2- to 4-fold range. Statistically significant protective associations were identified for high consumption of vegetables, fruits, cereals and tea. In contrast, frequent consumption of meat, animal fats and salt was associated with a moderately increased risk. This pooled analysis adds evidence for a carcinogenic effect of chronic thermal injury in the esophagus induced by the consumption of very hot drinks, including mate. Our study further confirms the protective effect of a dietary pattern characterized by daily consumption of fruits and vegetables and low consumption of meat and animal fats.

Aged↗

The frequency and spectrum of congenital anomalies in natural family planning users in South America: no increase in a case-control study. NFP-ECLAMC Group. Natural Family Planning. Latin-American Collaborative Study of Congenital Malformations.

Users of natural family planning (NFP) practice periodic abstinence, leading many to reason that such couples should show increased anomalies in offspring as a result of fertilization involving aging gametes. In an effort to complement our NFP cohort study, we currently conducted a case-control study in the same region (South America) in which the largest number of cases have been recruited for our cohort NFP study. During 1992-94, 5324 case-control pairs of mothers were interviewed during the immediate postpartum period in 18 maternity hospitals participating in the Latin-American Collaborative Study of Congenital Malformations: ECLAMC (Spanish acronym for Latin-American Collaborative Study of Congenital Malformations). Natural family planning (NFP) usage was recorded in 6% of mothers in the ECLAMC sample studied (n = 10,648). Overall, no significant differences in frequency of NFP usage were observed between malformed cases (349/5324 = 6.6%) and normal controls (303/5324 = 5.7%) (chi 2 = 3.3; df = 1; p > 0.05). No significant differences in sex ratios were observed between children of NFP user and non-user mothers. Of special interest is the lack of association between NFP and Down syndrome, the sentinel phenotype for the hypothesis of delayed fertilization (aging gametes).

Adult↗

Identification of the first strain of swine hepatitis E virus in South America and prevalence of anti-HEV antibodies in swine in Argentina.

In Argentina, a country considered non-endemic for hepatitis E virus (HEV) infection, serologic evidence of HEV infection has been observed in different human population groups. In other countries, a high degree of genetic relatedness has been observed between human and swine HEV genotype 3 sequences, suggesting zoonosis as one probable route of infection. This is the first identification of swine HEV in South America. HEV RNA was detected and sequenced in the ORF 1 and ORF 2 regions from swine fecal samples from a herd located in Pergamino, in the province of Buenos Aires. These strains all group into genotype 3 and exhibit a close relationship to two novel HEV variants previously identified in Argentina from sporadic acute cases of non-A to -C hepatitis in humans. In addition, using a modified commercial ELISA, the presence of anti-HEV antibodies was surveyed in five provinces across the country and all five showed a prevalence of HEV antibodies, ranging from 4% to 58%. The results suggest that swine could be an important reservoir for virus transmission in Argentina as has been suggested for other non-endemic areas. The Argentine human strains and swine strain described in this article seem to be closely related to a human Austrian strain, suggesting a potential European origin of HEV infection in these cases.

Animals↗