Eggs of Toxocara spp. in the environment and their public health implications

The high prevalence of Toxocara in cats, dogs and foxes results in the contamination of soil with infective eggs of Toxocara spp. which are found in soil samples from public and private places worldwide. In Poland the most contaminated areas were city backyards where 38-53% of soil samples were positive, especially in the spring. Human exposure to infection with Toxocara spp. was proportional to the prevalence of eggs in the samples examined but soil texture was not a critical factor in the degree of soil contamination. Eggs of Toxocara spp. placed on the ground penetrated a sand soil profile slowly. Their presence in the superficial layer of soils and the role of earthworms are instrumental in the dissemination of Toxocara eggs.     

Genotypic and phenotypic characteristics of L-line cells resistant to ethidium bromide

Stable mutants resistant to ethidium bromide in concentrations of 1 and 3 micrograms/ml have been selected in a single step in L cells. The frequency of spontaneously occurring ethidium bromide resistant clones after the exposure to 1 microgram/ml of the drug has been established as 5.10(-5). Resistant variants were induced following treatment with mutagen N-methyl-N-nitro-N-nitrosoguanidine. The resistant clones were shown to be resistant to higher concentration of the agent then which was used for selection. In multistep selection, a number of clones resistant to ethidium bromide in concentration up to 50 micrograms/ml was obtained. The alteration in the permeability of plasma membrane to the drug is the clue mechanism of the resistance.     

Cryptosporidium systematics and implications for public health

There is controversy in the taxonomy of Cryptosporidium parasites and the public health significance of Cryptosporidium isolates from various animals. Recent advances in molecular characterization of Cryptosporidium parasites have allowed the re-examination of species structure of the genus Cryptosporidium. Non-parvum Cryptosporidium spp and new C. parvum genotypes in immunocompromised humans can now be clearly detected. In this article, Lihua Xiao and colleagues summarize the current biological and molecular evidence for different Cryptosporidium spp, and the public health importance of these species and new C. parvum genotypes.     

Epidemiology of Helicobacter pylori infection and public health implications

This article summarizes the published literature concerning the epidemiology and public health implications of Helicobacter pylori infection published from April 2009 through March 2010. Prevalence of infection varied between 7 and 87% and was lower in European studies. All retrieved studies examining transmission of infection concluded that spread is from person-to-person. One study collecting stool and vomitus samples from patients with acute gastroenteritis detected H.?pylori DNA in 88% of vomitus and 74% of stool samples. Proposed risk factors for infection included male gender, increasing age, shorter height, tobacco use, lower socioeconomic status, obesity, and lower educational status of the parents in studies conducted among children. Decision analysis models suggest preventing acquisition of H.?pylori, via vaccination in childhood, could be cost-effective and may reduce incidence of gastric cancer by over 40%. As yet, no country has adopted public health measures to treat infected individuals or prevent infection in populations at risk.     

Epidemiology of Helicobacter pylori infection and public health implications

This review summarizes studies on the epidemiology and public health implications of Helicobacter pylori published in peer-reviewed journals from April 2010 through March 2011. Prevalence rates vary widely between different geographical regions and ethnic groups. An interesting study from the USA identified the degree of African ancestry as an independent predictor of H. pylori infection. Two studies have demonstrated early childhood as the period of transmission of infection and identified an infected sibling as an important risk factor. An oral-oral route of spread has been substantiated with several studies showing the presence of H. pylori in the oral cavity. Studies have shown the presence of H. pylori in drinking water and the role of poor living conditions and sanitation in H. pylori infection, supporting an oral-fecal route of spread. Screening for H. pylori as a gastric cancer pre-screening strategy has been described in Japan, and the importance of H. pylori eradication as a gastric cancer-prevention strategy has now been further emphasized in Japanese guidelines. Two studies have shown a decrease in the burden of dyspepsia and peptic ulcer disease with H. pylori eradication.     

Genotypic and phenotypic differentiation of an antifungal biocontrol strain belonging to Bacillus subtilis

Physiological and molecular fingerprints of biotechnologically relevant rhizobacteria are necessary for registration, patenting, recognition and quality checking of the strains. To characterize the biological control agent, Bacillus subtilis B2g, the strain was compared with other plant-associated B. subtilis isolates. Phenotypic characterization included biochemical and nutritional properties, in vitro activity and analysis of potential antagonistic mechanisms towards several plant pathogenic fungi. According to the phenotypic characteristics, it was not possible to differentiate the biocontrol agent from the other strains, although the enzymatic fingerprint was unique. Genotypic diversity among the isolates was characterized by molecular fingerprinting methods using REP-PCR (repetitive extragenomic palindromic PCR), and macrorestriction of genomic DNA and electrophoretic separation of DNA fragments by pulsed-field gel electrophoresis (PFGE). A protocol for PFGE analysis using restriction enzyme SfiI for B. subtilis was developed. PFGE typing of B. subtilis B2g resulted in a unique fingerprint. Therefore, it was possible to differentiate B. subtilis B2g, the biocontrol agent of Phytovit, from other antifungal B. subtilis isolates.     

Genotypic and phenotypic spectrum in tricho-rhino-phalangeal syndrome types I and III

Tricho-rhino-phalangeal syndrome (TRPS) is characterized by craniofacial and skeletal abnormalities. Three subtypes have been described: TRPS I, caused by mutations in the TRPS1 gene on chromosome 8; TRPS II, a microdeletion syndrome affecting the TRPS1 and EXT1 genes; and TRPS III, a form with severe brachydactyly, due to short metacarpals, and severe short stature, but without exostoses. To investigate whether TRPS III is caused by TRPS1 mutations and to establish a genotype-phenotype correlation in TRPS, we performed extensive mutation analysis and evaluated the height and degree of brachydactyly in patients with TRPS I or TRPS III. We found 35 different mutations in 44 of 51 unrelated patients. The detection rate (86%) indicates that TRPS1 is the major locus for TRPS I and TRPS III. We did not find any mutation in the parents of sporadic patients or in apparently healthy relatives of familial patients, indicating complete penetrance of TRPS1 mutations. Evaluation of skeletal abnormalities of patients with TRPS1 mutations revealed a wide clinical spectrum. The phenotype was variable in unrelated, age- and sex-matched patients with identical mutations, as well as in families. Four of the five missense mutations alter the GATA DNA-binding zinc finger, and six of the seven unrelated patients with these mutations may be classified as having TRPS III. Our data indicate that TRPS III is at the severe end of the TRPS spectrum and that it is most often caused by a specific class of mutations in the TRPS1 gene.     

The public health implications of maternal care trade-offs

The socioeconomic and ethnic characteristics of parents are some of the most important correlates of adverse health outcomes in childhood. However, the relationships between ethnic, economic, and behavioral factors and the health outcomes responsible for this pervasive finding have not been specified in child health epidemiology. The general objective of this paper is to propose a theoretical approach to the study of maternal behaviors and child health in diverse ethnic and socioeconomic environments. The specific aims are: (a) to describe a causal pathway between the utility that women obtain through work outside the home and through child care and disease hazard rates in childhood using an optimization model; (b) to specify the influence of ethnic and socioeconomic factors on model constraints; (c) to use the model as a tool to learn about how different combinations of maternal wage labor and child care time might influence child health outcomes in diverse social contexts; (d) to identify parameters that will require measurement in future research; (e) to discuss research strategies that will enable us to obtain these measurements; and (f) to discuss the implications of the model for biostatistical modeling and public health intervention. Optimization models are powerful heuristic tools for understanding how ethnic, environmental, family, and personal characteristics can place important constraints on both the quality and quantity of care that women can provide to their children. They provide a quantitative appreciation for the difficult trade-offs that most women face between working in order to purchase basic goods that children cannot do without (e.g., food, clothing, shelter, health insurance), and increasing offspring well-being through child care (e.g., training in social skills, affection, protection from environmental hazards, help with homework). The research was funded by a Faculty Scholars Award from the William T. Grant Foundation to A. Magdalena Hurtado. A. Magdalena Hurtado, Ph.D., is an associate professor in the Department of Anthropology, University of New Mexico. Her research interests include the origins of the sexual division of labor, epidemiology of indigenous peoples, disease susceptibility, the development and intergenerational transmission of antigens and immune defense, immune function and allergic sensitization, and trauma. She also works on public health interventions, biological capital and poverty, and land tenure and human rights in native communities of South America. Carol Lambourne, M.Sc., is a doctoral candidate in the Department of Anthropology, University of New Mexico. Her research interests are evolutionary models of child and adolescent development, life history theory, family composition and investment patterns, pubertal timing and psychosexual maturation, juvenile stress, and infanticide. Kim Hill, Ph.D., is a professor in the Department of Anthropology, University of New Mexico. His research interests are modern hunter-gatherers, including extensive fieldwork in lowland South America. Current topics of interest include human evolution, economic strategies, life history theory, the evolution of cooperation, and the emergence of social norms enforced by punishment. He is also involved in economic development, health and education projects with lowland South American native populations. Karen Kessler received her M.S. in Anthropology from the University of New Mexico in 1996. Her research interests are the application of mathematical modeling to the prevention of diabetes and other causes of morbidity and mortality in historical populations.     

Drug-resistant malaria: molecular mechanisms and implications for public health

Resistance to antimalarial drugs has often threatened malaria elimination efforts and historically has led to the short-term resurgence of malaria incidences and deaths. With concentrated malaria eradication efforts currently underway, monitoring drug resistance in clinical settings complemented by in vitro drug susceptibility assays and analysis of resistance markers, becomes critical to the implementation of an effective antimalarial drug policy. Understanding of the factors, which lead to the development and spread of drug resistance, is necessary to design optimal prevention and treatment strategies. This review attempts to summarize the unique factors presented by malarial parasites that lead to the emergence and spread of drug resistance, and gives an overview of known resistance mechanisms to currently used antimalarial drugs.     

Genotypic and phenotypic characterization of genetic differentiation and diversity in the USDA rice mini-core collection

A rice mini-core collection consisting of 217 accessions has been developed to represent the USDA core and whole collections that include 1,794 and 18,709 accessions, respectively. To improve the efficiency of mining valuable genes and broadening the genetic diversity in breeding, genetic structure and diversity were analyzed using both genotypic (128 molecular markers) and phenotypic (14 numerical traits) data. This mini-core had 13.5 alleles per locus, which is the most among the reported germplasm collections of rice. Similarly, polymorphic information content (PIC) value was 0.71 in the mini-core which is the highest with one exception. The high genetic diversity in the mini-core suggests there is a good possibility of mining genes of interest and selecting parents which will improve food production and quality. A model-based clustering analysis resulted in lowland rice including three groups, aus (39 accessions), indica (71) and their admixtures (5), upland rice including temperate japonica (32), tropical japonica (40), aromatic (6) and their admixtures (12) and wild rice (12) including glaberrima and four other species of Oryza. Group differentiation was analyzed using both genotypic distance Fst from 128 molecular markers and phenotypic (Mahalanobis) distance D(2) from 14 traits. Both dendrograms built by Fst and D(2) reached similar-differentiative relationship among these genetic groups, and the correlation coefficient showed high value 0.85 between Fst matrix and D(2) matrix. The information of genetic and phenotypic differentiation could be helpful for the association mapping of genes of interest. Analysis of genotypic and phenotypic diversity based on genetic structure would facilitate parent selection for broadening genetic base of modern rice cultivars via breeding effort.