Congenital Baylisascaris sp. larval migrans in a newborn lamb

A 3-day-old domestic lamb, moribund since birth, was submitted as part of a diagnostic effort concerning weak newborn lambs due possibly to congenital Bluetongue virus infection. Gross lesions were consistent with such an event. Histologic examination of cerebrum and cerebellum revealed multiple granulomas, the age of which required prenatal development. These contained larvae compatible with those of Baylisascaris sp. This finding together with evidence that parents of children with neural larval migrans have been seropositive for ascarid antigen suggests that mammalian fetuses in general should be added to the list of those at risk for neural larva migrans due to ascarid parasites.     

Reducing Sexual Violence by Increasing the Supply of Toilets in Khayelitsha,South Africa: A Mathematical Model

Background

Sexual violence is a major public health issue, affecting 35% of women worldwide. Major risk factors for sexual assault include inadequate indoor sanitation and the need to travel to outdoor toilet facilities. We estimated how increasing the number of toilets in an urban township (Khayelitsha, South Africa) might reduce both economic costs and the incidence and social burden of sexual assault.

Methods

We developed a mathematical model that links risk of sexual assault to the number of sanitation facilities and the time a woman must spend walking to a toilet. We defined a composite societal cost function, comprising both the burden of sexual assault and the costs of installing and maintaining public chemical toilets. By expressing total social costs as a function of the number of available toilets, we were able to identify an optimal (i.e., cost-minimizing) social investment in toilet facilities.

Findings

There are currently an estimated 5600 toilets in Khayelitsha. This results in 635 sexual assaults and US$40 million in combined social costs each year. Increasing the number of toilets to 11300 would minimize total costs ($35 million) and reduce sexual assaults to 446. Higher toilet installation and maintenance costs would be more than offset by lower sexual assault costs. Probabilistic sensitivity analysis shows that the optimal number of toilets exceeds the original allocation of toilets in the township in over 80% of the 5000 iterations of the model.

Interpretation

Improving access to sanitation facilities in urban settlements will simultaneously reduce the incidence of sexual assaults and overall cost to society. Since our analysis ignores the many additional health benefits of improving sanitation in resource-constrained urban areas (e.g., potential reductions in waterborne infectious diseases), the optimal number of toilets identified here should be interpreted as conservative.     

Progress of ecological parasitology--parasite communities

Many of the major development in the field of parasite community ecology have been due to a switch in focus from a search for pattern to investigation of the processes that produce those patterns. This switch has been accompanied by a recognition that different processes operate at the scale of the individual host (processes determining host specificity and attributes of the niches of the parasites), within the unit of habitat (processes determining population dynamics, exchange of parasites, and transmission), and among units of habitat (processes determining colonization, extinction, or local speciation of parasites). Further developments are likely to depend upon the coordinated use of models, experimental approaches, and field observations aimed at clarifying the conditions under which the processes at each scale became particularly important.     

Crisis in our schools: survey of sanitation facilities in schools in Bloomsbury health district.

OBJECTIVE--To survey sanitation facilities in schools in Bloomsbury health district. DESIGN--Postal questionnaire. SETTING--Inner London health district. PARTICIPANTS--School nurses. RESULTS--16 of 17 school nurses responded (37 of 41 schools). Fifteen schools did not have the minimum number of toilets and hand basins established in the Education (School Premises) Regulations 1981. In two schools toilets were kept locked for most of the day. In 10 schools toilet paper was not always available, and three of five secondary schools did not have disposal units for sanitary towels in the girls'' toilet areas. In 18 of the schools the toilets were not kept adequately clean. CONCLUSIONS--These conditions raise serious questions about environmental health, with the potential for the spread of infectious diseases, and undermine attempts to teach children basic hygiene. Health professionals have an important role in assessing health and safety standards in schools and ensuring that necessary improvements are made.     

Purification and properties of fructose diphosphate aldolase from Ascaris suum muscle

A fructose diphosphate aldolase has been isolated from ascarid muscle and crystallized by simple column chromatography and an ammonium sulfate fractionation procedure. It was found to be homogeneous on electrophoresis and Sephadex G-200 gel filtration. This enzyme has a fructose diphosphate/fructose 1-phosphate activity ratio close to 40 and specific activity for fructose diphosphate cleavage close to 11. K_m values of ascarid aldolase are 1 × 10⁻⁶m and 2 × 10⁻³m for fructose diphosphate and fructose 1-phosphate, respectively. The enzyme reveals a number of catalytic and molecular properties similar to those found for class I fructose diphosphate aldolases. It has C-terminal functional tyrosine residues, a molecular weight of 155,000, and is inactivated by NaBH₄ in presence of substrate. Data show the presence of two types of subunits in ascarid aldolase; the subunits have different electrophoretic mobilities but similar molecular weights of 40,000. Immunological studies indicate that the antibody-binding sites of the molecules of the rabbit muscle aldolase A or rabbit liver aldolase B are structurally different from those of ascarid aldolase. Hybridization studies show the formation of one middle hybrid form from a binary mixture of the subunits of ascarid and rabbit muscle aldolases. Hybridization between rabbit liver aldolase and ascarid aldolase was not observed. The results indicate that ascarid aldolase is structurally more related to the mammalian aldolase A than to the aldolase B.     

Principles of Integrated Control of Disease Vectors

A symposium at the AAAS meeting in 1957 provided an importantimpetus for biological and chemical control of plant and animalpests. The World Health Organization has recognized the needfor an ecology-based unit to detect agents for control of diseasevectors, and established an International Reference Center tolocate eligible biological agents. Bacillus thuringiensis, severalviruses of insects, sterilization of males, and other techniqueshave been developed to control disease vectors. Nevertheless,chemical techniques and to a much lesser extent sanitation or"cultural" techniques predominate today. Additional alternativetechniques include sterility induced by radiation; use of predators,pathogens, and parasites; genetic incompatibility; use of chemosterilantsand attractants and use of hormones. None of these, however,has been developed to the level necessary for use in an integratedprogram.     

A proposal of a fuzzy rule-based system for the analysis of health and health environments in Brazil

A challenging activity in the promotion of sustainable development is to synthesise indicators that can support decision-making. In developing countries such as Brazil, the use of information in support of the health and health-related environment of humans needs improvement. This paper presents a proposal for a system that can evaluate human health and urban environment sanitation in an integrated manner. The indicators selected for human health were child mortality rate, mortality rate due to acute diarrhoea for all ages and 1–4-year-old mortality rate due to acute respiratory tract infections. Environmental sanitation has been represented by indicators of sanitation coverage, such as sewerage. The paper describes the design of a fuzzy linguistic model that synthesises these indicators. The designed fuzzy rule-based system has proved to be a useful tool to integrate information and assist in the public planning of interrelated areas.     

Fatal Baylisascaris larva migrans in a colony of Japanese macaques kept by a safari-style zoo in Japan

A colony of Japanese macaques (Macaca fuscata fuscata) kept by a safari-style zoo in Japan experienced 9 sporadic cases of fatal neurological diseases, such as epilepsy and posterior paralysis, during the 12 yr from 1989 to 2001. This macaque colony consisted of approximately 30 animals, on average, during this period, and the macaques shared their living space with II American black bears (Ursus americanus) harboring zoonotic roundworms (Baylisascaris transfuga). Close to this enclosure, a cote for 2-3 raccoons (Procyon lotor) was placed, and raw sewage from this cote ran into a shallow drain in the area for macaques and bears. However, fecal examinations in recent years did not detect the infection of raccoons with zoonotic roundworms (Baylisascaris procyonis). Postmortem histological examination of the latest 2 ill macaques detected multifocal malacia in the brain; 2 ascarid larvae of 60 microm maximum width were encapsulated in the cerebrum and lungs of 1 of the animals. To determine the causative ascarid species of the fatal larva migrans, we analyzed 2 additional encapsulated Baylisascaris larvae collected from formalin-fixed lungs by morphological and molecular approaches. This sporadic outbreak is the second record of Baylisascaris larva migrans in animals in Japan.     

The state of the art of paleoparasitological research in the Old World

Paleoparasitology in the Old World has mainly concerned the study of latrine sediments and coprolites collected from mummified bodies or archaeological strata, mostly preserved by natural conditions. Human parasites recovered include cestodes, trematodes, and nematodes. The well preserved conditions of helminth eggs allowed paleoepidemiological approaches taking into account the number of eggs found by archaeological stratum. Tentatively, sanitation conditions were assessed for each archaeological period.     

Outcrossing increases infection success and competitive ability: experimental evidence from a hermaphrodite parasite

Abstract.— The maintenance of two genetically distinct reproductive modes such as outcrossing and selfing within a population of animals or plants is still a matter of considerable debate. Hermaphroditic parasites often reproduce either alone by selfing or in pairs by outcrossing. They can be used as a model to study potential benefits of outcrossing. Any advantage from outcrossing may be important, especially in host-parasite coevolution, but has not, to our knowledge, been studied yet in any parasite species. We studied the potential effect of outcrossing in a tapeworm, Schis-tocephalus solidus , on both infection success and growth in its first intermediate host, the copepod Macrocyclops albidus . Tapeworms that had been obtained from natural populations of three-spined sticklebacks ( Gasterosteus acu-leatus ) were allowed to reproduce either alone or in pairs, in an in vitro system that replaced the final host's gut. This resulted in either selfed or outcrossed offspring, respectively. In one part of the experiment, copepods were exposed to either selfed or outcrossed parasites, in a second part to both types simultaneously, in order to study the effect of competition between them. To discriminate parasites of either origin within the same host, a novel method for fluorescent vital labeling was used. We show here for the first time that outcrossed parasites had a higher infection success and faster development in the host. This advantage of outcrossing became apparent only in the competitive situation, in which superior abilities of parasites to extract limiting resources from the host become crucial.     

Études du Paléolithique du Japon à partir des téphras

Many studies and discussions have been made on the problem of when the earliest human beings appeared in Japan. In general, hominid fossils in the latest Pleistocene are not preserved except for coralline limestone sequence in Ryukyu islands, but earlier Paleolithic tools were excavated from volcanic ash soil with a ¹⁴C age of about 30,000–35,000 yr. BP or younger at several archeological sites in almost all Japan. Recent studies, however, show a need for revision and refinement of these ages because calibration techniques have progressed from conventional to calendar ages and high-resolution oxygen isotope chronology has given a global standard sequence. Aïra-Tn tephra (AT), the most important time-marker of the Paleolithic age in Japan, was formerly dated at 21,000–22,000 yr ¹⁴C BP by conventional radiocarbon methods but was dated again at ca. 24,500 yr ¹⁴C BP by accelerated mass spectrometry radiocarbon methods. However, it has been further calibrated to a high-resolution calendar age of 30,000 cal yr. by varve chronology of lake sediments of Suigetsu of central Japan, well matched with combined date between oxygen isotope dates based and calibration from AMS radiocarbon dates. As the earliest Paleolithic tools in south Kanto are found in volcanic ash soil significantly below AT ash and above Sambe-Ikeda ash (SI, ca.46 ka), just above the oxygen isotopic stage 3.3, they are estimated to be dated slightly older than 40 ka. Palaeo-environment at that time is estimated mild to cool climate and relatively low sea level after the oxygen isotope stage 3.3. Sill land bridges between Japan islands and continents have not been formed at major straits. We have not yet obtained useful data for calibration older than ca. 45 ka. Also, correlation of oxygen isotopic fluctuation with the terrestrial sequences is incomplete in Stage 3.     

Climatic conditions and child height: Sex-specific vulnerability and the protective effects of sanitation and food markets in Nepal

Environmental conditions in early life are known to have impacts on later health outcomes, but causal mechanisms and potential remedies have been difficult to discern. This paper uses the Nepal Demographic and Health Surveys of 2006 and 2011, combined with earlier NASA satellite observations of variation in the Normalized Difference Vegetation Index (NDVI) at each child’s location and time of birth to identify the trimesters of gestation and periods of infancy when climate variation is linked to attained height later in life. We find significant differences by sex: males are most affected by conditions in their second trimester of gestation, and females in the first three months after birth. Each 100-point difference in NDVI at those times is associated with a difference in height-for-age z-score (HAZ) measured at age 12–59 months of 0.088 for boys and 0.054 for girls, an effect size similar to that of moving within the distribution of household wealth by close to one quintile for boys and one decile for girls. The entire seasonal change in NDVI from peak to trough is approximately 200–300 points during the 2000–2011 study period, implying a seasonal effect on HAZ similar to one to three quintiles of household wealth. This effect is observed only in households without toilets; in households with toilets, there is no seasonal fluctuation, implying protection against climatic conditions that facilitate disease transmission. We also use data from the Nepal Living Standards Surveys on district-level agricultural production and marketing, and find a climate effect on child growth only in districts where households’ food consumption derives primarily from their own production. Robustness tests find no evidence of selection effects, and placebo regression results reveal no significant artefactual correlations. The timing and sex-specificity of climatic effects are consistent with previous studies, while the protective effects of household sanitation and food markets are novel indications of mechanisms by which households can gain resilience against adverse climatic conditions.     

Socio-Economic Factors of Bacillary Dysentery Based on Spatial Correlation Analysis in Guangxi Province,China

Background

In the past decade, bacillary dysentery was still a big public health problem in China, especially in Guangxi Province, where thousands of severe diarrhea cases occur every year.

Methods

Reported bacillary dysentery cases in Guangxi Province were obtained from local Centers for Diseases Prevention and Control. The 14 socio-economic indexes were selected as potential explanatory variables for the study. The spatial correlation analysis was used to explore the associations between the selected factors and bacillary dysentery incidence at county level, which was based on the software of ArcGIS10.2 and GeoDA 0.9.5i.

Results

The proportion of primary industry, the proportion of younger than 5-year-old children in total population, the number of hospitals per thousand persons and the rates of bacillary dysentery incidence show statistically significant positive correlation. But the proportion of secondary industry, per capital GDP, per capital government revenue, rural population proportion, popularization rate of tap water in rural area, access rate to the sanitation toilets in rural, number of beds in hospitals per thousand persons, medical and technical personnel per thousand persons and the rate of bacillary dysentery incidence show statistically significant negative correlation. The socio-economic factors can be divided into four aspects, including economic development, health development, medical development and human own condition. The four aspects were not isolated from each other, but interacted with each other.     

Intestinal Parasite Infections in Symptomatic Children Attending Hospital in Siem Reap,Cambodia

BackgroundInfections with helminths and other intestinal parasites are an important but neglected problem in children in developing countries. Accurate surveys of intestinal parasites in children inform empirical treatment regimens and can assess the impact of school based drug treatment programmes. There is limited information on this topic in Cambodia.MethodsIn a prospective study of intestinal parasites in symptomatic children attending Angkor Hospital for Children, Siem Reap, Cambodia, April-June 2012, samples were examined by microscopy of a direct and concentrated fecal sample. Two culture methods for hookworm and Strongyloides stercoralis were employed when sufficient sample was received. Demographic, clinical and epidemiological data were collected.Conclusions/SignificanceThis study confirms the importance of intestinal parasitic infections in symptomatic Cambodian children and the need for adequate facilities for laboratory diagnosis together with education to improve personal hygiene and sanitation.     

Molecular characterization and phylogenetic analysis of ascarid nematodes from twenty-one species of captive wild mammals based on mitochondrial and nuclear sequences

SUMMARY Although ascarid nematodes are important parasites of wild animals of public health concern, few species of ascarids from wild animals have been studied at the molecular level so far. Here, the classification and phylogenetic relationships of roundworms from 21 species of captive wild animals have been studied by sequencing and analysis of parts of the ribosomal 18S and 28S genes and the mitochondrial (mt) 12S gene. Phylogenetic relationships were inferred by 3 methods (NJ/MP/ML) based on the data of single gene sequences and concatenated sequences. Homology analysis indicated that the 18S sequences were conserved among roundworms from all 21 species and that 28S showed interspecies variability. Divergence levels displayed in 12S suggested that 12S appears to be either intra- or interspecifically variable. Evolutionary trees indicated that the ascarids split into 2 families, 4 genera and 7 species, with high bootstrap support for each clade. Combined trees suggested that Baylisascaris ailuri is more closely related to B. transfuga than to B. schroederi. This study provides useful molecular markers for the classification, phylogenetic analysis and epidemiological investigation of roundworms from wild animals.     

Intestinal parasitic infections in pre-school children in the Niger Delta

Stool specimens from 1,062 pre-school children in the Niger Delta were examined for the presence of intestinal parasites. Of that number, 77.6% harboured one or more than one species of intestinal parasites. Ascaris lumbricoides (51.9%) and Trichuris trichiura (41.7%) were the most prevalent species recorded. Other parasites harboured by these children included Hymenolepis sp. (18.3%), Giardia lamblia (9.2%), Entamoeba histolytica (4.6%), Strongyloides stercoralis (1.4%). Hookworm, Taenia sp., Isospora sp. and Trichostrongylus sp. occurred in less than 1% of the children examined. These high rates of infection are associated with poor sanitary conditions prevalent in the area. Improvement of environmental sanitation is advised to reduce human sufferings caused by parasites in that area particularly among children.     

Distribution, prevalence, and genetic characterization of Baylisascaris procyonis in selected areas of Georgia

Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasite has historically been absent in the southeastern United States, it has been found in isolated regions in the Appalachian Mountains and was recently documented in DeKalb County, Georgia. The first objective of the current study was to investigate the distribution and prevalence of B. procyonis in selected populations of raccoons in Georgia. Intestinal tracts of 312 raccoons from 25 Georgia counties were examined for B. procyonis. The only county where B. procyonis was detected was Clarke County, where 12 of 116 (10.3%) raccoons were infected. In Clarke County, significantly more juveniles (P = 0.049) were infected compared with adults, and no differences in prevalence were noted by sex, season of capture, or land use (rural vs. urban); however, significantly (P = 0.0370) higher worm burdens were found in infected raccoons from urban/suburban locations compared with rural areas. In addition, Toxascaris leonina , a morphologically similar ascarid, was found in 3 raccoons from Clarke County (n = 2) and Morgan County (n = 1). A second objective was to determine if sequence polymorphisms were associated with B. procyonis from different geographic regions. Because sequences from a single worm from Japan had been entered into GenBank, we obtained nematodes from Kentucky and Texas for comparison with our samples from Georgia. Sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer (ITS) -1 and ITS-2 regions confirmed Georgia samples were B. procyonis. Although several polymorphic bases were observed within both ITS regions, none was associated with a particular geographic location. These data indicate that the distribution of B. procyonis within Georgia is increasing and only limited genetic variation is present in the rRNA and ITS gene regions among B. procyonis from the southern United States and introduced populations in Japan.     

Fine binding specificities to Ascaris suum and Ascaris lumbricoides antigens of the sera from patients of probable visceral larva migrans due to Ascaris suum

Fine binding specificities to Ascaris suum and A. lumbricoides antigens of the sera from patients with probable visceral larva migrans (VLM) due to A. suum infection were examined. Although multiple-dot enzyme-linked immunosorbent assay (ELISA) was found to be useful for the primary screening of patients, identification of the responsible species was sometimes difficult due to extensive cross reactions with other ascarid parasite antigens. Fine resolution to determine the causative pathogen was obtained by a rather classical Ouchterlony's double immunodiffusion test. The difference in the binding of the patients' sera to A. suum and A. lumbricoides antigens was also demonstrated by an inhibition ELISA. The patients' antibodies bound with higher avidity to the A. suum antigen than to the A. lumbricoides and Toxocara canis antigens. Combination of at least two different immunological assay methods is recommended for the diagnosis of VLM due to ascarid parasites.     

Disappearance of specific antibodies in patients with chronic schistosomiasis japonica by treatment with praziquantel

We tested effects of praziquantel, an antischistosomal compound, on clinical and immunological parameters of chronic schistosomiasis japonica. Two Japanese patients, who had high antibody titers to Schistosoma japonicum antigens but no fecal schistosome eggs or no or mild symptoms complained, were treated with praziquantel. Within two years after treatment, anti-schistosome antibodies in sera from the patients became negative in enzyme-linked immunosorbent assay. There was no significant alteration in cellular immunity to the parasite. Although S. japonicum infection is believed to have been eradicated in Japan, our present results seem to suggest the possibility that a few Japanese individuals, who have high anti-schistosome antibody, still harbor live parasites.     

Trematodes enhance the development of the nematode-trapping fungus Arthrobotrys (Duddingtonia) flagrans

The capability of helminth (nematode and trematode) parasites in stimulating nematode trap and chlamydospore development of the nematophagous fungus Arthrobotrys (formerly Duddingtonia) flagrans was explored. Dead adult specimens of trematodes (the liver fluke Fasciola hepatica and the rumen fluke Calicophoron daubneyi) and nematodes (the ascarid Parascaris equorum and the strongylid Oesophagostomum spp.), as well as their secretory products, were placed onto corn meal agar plates concurrently inoculated with A. flagrans. Trapping organs were observed after 5 d and chlamydospores after 16 d, including in the control plates in the absence of parasitic stimulus. However, our data shows that both nematodes and trematodes increase trap and chlamydospore production compared with controls. We show for the first time that significantly higher numbers of traps and chlamydospores were observed in the cultures coinoculated with adult trematodes. We conclude that both the traps and chlamydospores formation are not only related to nematode-specific stimuli. The addition of secretory products of the trematode C. daubneyi to culture medium has potential for use in the large scale production of chlamydospores.