Neuronavigation guided surgery for parenchymal neurocysticercosis in two patients

Summary Neurocysticercosis is a rare disease in the Baltic area while it is common in the endemic regions. Two patients with serologically negative parenchymal neurocysticercosis from our neurosurgical department who underwent extirpation of the cystic lesions with neuronavigation guided surgery are reported in this paper. Though most publications propose medical treatment with albendazole and praziquantel for parenchymal neurocysticercosis, surgery can be an option for diagnosis and treatment in conjunction with cysticidal medication if the diagnosis is unclear particularly in non-endemic areas.     

Differential requirements for interleukin (IL)‐4 and IL‐13 in protein contact dermatitis induced by Anisakis

Background: Exposure to antigens of the fish parasite Anisakis is associated with the development of protein contact dermatitis in seafood‐processing workers. Understanding the basic mechanisms controlling allergic sensitization through the skin is critical for designing therapies that will prevent the progression of allergic disease. Objective: To investigate the roles of interleukin (IL)‐4, IL‐13 and the IL‐4Rα in both local skin pathology and systemic sensitization following epicutaneous exposure to Anisakis proteins. Methods: BALB/c wild‐type (WT) mice and mice deficient in IL‐4, IL‐13 or IL‐4 and IL‐13, as well as mice with cell‐specific impairment of IL‐4Rα expression, were sensitized to Anisakis antigen by repeated epicutaneous application of Anisakis extract. Following this sensitization, skin pathology was recorded and systemic responses were investigated. Intravenous challenge with Anisakis extract was performed to test for the development of biologically relevant systemic sensitization. Results: In WT mice, epicutaneous sensitization with Anisakis larval antigens induced localized inflammation, epidermal hyperplasia, production of T_H2 cytokines, antigen‐specific IgE and IgG1. Intravenous challenge of sensitized mice resulted in anaphylactic shock. Interestingly, IL‐13 deficient mice failed to develop epidermal hyperplasia and inflammation, whilst anaphylaxis was reduced only in strains deficient either in IL‐4 only, or deficient in IL‐4 and IL‐13 concurrently, as well as in mice deficient in IL‐4Rα or with impaired IL‐4Rα expression on CD4⁺ T cells. Conclusions: Interleukin‐13 plays a central role in protein contact dermatitis associated with repeated epicutaneous exposure to Anisakis extract, whereas IL‐4 drives systemic sensitization and resultant anaphylactic shock.     

Label-free detection of Babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated flow cytometer

Impedance spectroscopy is a powerful tool for label-free analysis and characterisation of living cells. In this work, we achieved the detection of Babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated flow cytometer. The cellular modifications caused by the intracellular parasite result in a shift in impedance which can be measured dielectrically. Thus, a rapid cell-by-cell detection with microliter amounts of reagents is possible. Unlike other diagnostic tests, this method does not depend on extensive sample pre-treatment or expensive chemicals and equipment.     

日本血吸虫谷胱甘肽-S-转移酶在虫卵阶段的定位

目的探讨谷胱甘肽-S-转移酶(Sj26GST)在虫卵阶段的表达、定位和重组蛋白(rSj26GST)的免疫诊断价值。方法从感染日本血吸虫尾蚴6周的兔肝脏中分离虫卵,分别用RT-PCR和免疫印迹(Western blotting)法检测Sj26GST基因在虫卵阶段的转录和翻译;同时用兔肝做免疫组化观察Sj26GST在虫卵内的分布。利用纯化的rSj26GST和日本血吸虫可溶性虫卵抗原(SEA),采用间接ELISA法检测急、慢性血吸虫病患者和正常人血清。结果RT-PCR从血吸虫虫卵中扩增670bp的基因片断,Western blotting证明在虫卵阶段Sj26GST的表达;同时免疫组化显示Sj26GST主要分布在虫卵内毛蚴两边的侧腺。rSj26GST检测急、慢性血吸虫病患者和正常人血清的阳性率分别为92%、80%和0;用SEA检测以上标本,阳性率分别为96%、84%和2%。结论Sj26GST是SEA的主要组分之一,能刺激机体产生高滴度的抗体;rSj26GST为抗原诊断日本血吸虫病显示出高度的敏感性和特异性,具有实用价值。     

Cellular FLIP long isoform transgenic mice overcome inherent Th2-biased immune responses to efficiently resolve Leishmania major infection

c-FLIP(L) expression in T cells is required for mounting effective T cell responses and can also be critical for effector T cell differentiation, as has recently been shown by a number of in vivo studies in conditional knockout and transgenic mouse systems. Available data supports therefore a novel immunomodulatory role of this anti-apoptotic protein besides its traditionally proposed function in homeostatic maintenance of T cell populations. In this study, the responses to infection with Leishmania major of mice over-expressing FLIP(L) specifically in the T cell compartment (TgFLIP(L)) are assessed. Although previous studies have shown that FLIP(L) drives T cells towards a T(h)2 differentiation programme in various autoimmune and allergic paradigms, in this study, we show that TgFLIP(L) are able to overcome this T(h)2 bias in a dermal L. major infection model to mount a robust T(h)1 response to pathogen and effectively clear infection. Our results suggest that vaccination protocols designed to enhance FLIP(L) expression in T cells may be useful for the treatment of autoimmune diseases like multiple sclerosis, without necessarily compromising immune responses towards infectious agents.     

Plasmodium liver stage developmental arrest by depletion of a protein at the parasite-host interface

Plasmodium parasites of mammals, including the species that cause malaria in humans, infect the liver first and develop there into clinically silent liver stages. Liver stages grow and ultimately produce thousands of first-generation merozoites, which initiate the erythrocytic cycles causing malaria pathology. Here, we present a Plasmodium protein with a critical function for complete liver stage development. UIS4 (up-regulated in infective sporozoites gene 4) is expressed exclusively in infective sporozoites and developing liver stages, where it localizes to the parasitophorous vacuole membrane. Targeted gene disruption of UIS4 in the rodent model malaria parasite Plasmodium berghei generated knockout parasites that progress through the malaria life cycle until after hepatocyte invasion but are severely impaired in further liver stage development. Immunization with UIS4 knockout sporozoites completely protects mice against subsequent infectious WT sporozoite challenge. Genetically attenuated liver stages may thus induce immune responses, which inhibit subsequent infection of the liver with WT parasites.     

Conservative management of neurocysticercosis in a patient with hematopoietic stem cell transplantation: a case report and review

Neurocysticercosis, an infection of the central nervous system with the larval stage of the cestode Taenia solium, is common in developing countries but its occurrence and management in allogeneic hematopoietic stem cell transplantation (HSCT) has not been reported previously, to our knowledge. We report the case of an immigrant female patient who underwent a matched‐related allogeneic HSCT for acute lymphoblastic leukemia and was incidentally found to have a solitary viable neurocysticercosis lesion. However, despite severe immunosuppression, the size of the cyst did not increase. More importantly, restoration of the immune system did not induce significant inflammation or seizures. Subsequent follow‐up demonstrated complete resolution of the neurocysticercosis lesion. Thus, in the setting of HSCT, an asymptomatic patient with a single neurocysticercosis lesion was successfully managed without the use of anthelmintics, steroids, or anti‐epileptics.     

Local host specialization,host-switching,and dispersal shape the regional distributions of avian haemosporidian parasites

The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.A regional community can be thought of as a set of species whose distributions partially overlap within a large geographic area (1, 2). The structure of the regional community (i.e., the relative abundances of species across space and the degree to which populations cooccur) is governed by local (e.g., interspecific competition) and regional (e.g., species diversification and dispersal) processes (3). Although regional communities include all species, parasites and pathogens are rarely considered integral community members (4). Indeed, impacts of parasites on community structure are frequently associated with epidemics—often following introductions to nonnative regions—that have driven naïve hosts to extinction or near extinction (5–7). However, parasites likely play a critical role in shaping regional community structure. Parasites can comprise a large proportion of the community biomass (8), form the majority of links in a community food web (9), and influence regional diversity by variously accelerating (10) or slowing (11) host diversification.Nevertheless, few studies have investigated the processes influencing the regional community structure of both parasites and their hosts. Parasite populations are integrated into community studies with difficulty, partly because these populations are distributed across multiple dimensions—space, host species, and host individuals (12)—and also because parasites are difficult to sample. Moreover, although parasites tend to specialize on one or a few host species, host-breadth may vary across a parasite’s range (13).Regional studies of birds and their dipteran-vectored haemosporidian (“malaria”) blood parasites (14–19) have shown that many parasites are heterogeneously distributed across space despite the availability of suitable hosts. Specialized associations between specific parasites and vectors (20–22) may drive such heterogeneity, although a recent analysis suggests that parasite–host compatibility is also important (23), and local coevolutionary relationships between parasites and their hosts likely influence geographic distributions of both host and parasite populations (11, 14, 15). However, most regional studies of these parasites have focused on individual host species (24–30).Here, we investigate the regional community structure of avian hosts and their haemosporidian parasites with respect to abiotic and biotic drivers of both host and parasite distributions. We surveyed local assemblages of avian haemosporidian parasites across eastern North America and related the distributions of individual parasite lineages to regional climate variation and to the distributions and abundances of their avian hosts. Community dissimilarities between sampling locations based on host assemblage structure (i.e., the relative abundances of potential host species) were positively correlated with those based on parasite assemblage structure, suggesting interdependence of host and parasite population distributions. However, when controlling statistically for that interdependence, local host assemblages responded strongly to environmental gradients and differed more with increasing geographic separation, whereas parasite assemblages did not. This finding suggests that haemosporidian parasites disperse readily across the distributions of their host populations in eastern North America, independently of difference in climate and geographic distance. The degree to which some parasite lineages specialized on particular hosts varied across years and locations, and the nonrandom parasite lineage turnover across the distribution of one well-sampled host species suggested that adaptations of hosts and parasites may also shape regional community structure. Despite evidence of pathogenicity of haemosporidian parasites in birds (31), correlations between host abundances and parasite relative abundances across the region were statistically indistinguishable from random. Taken together, these results suggest that the distributions of parasite populations largely follow the distributions of their hosts but that parasites readily switch hosts and may replace each other across the ranges of individual hosts, resulting in a complex and dynamic regional community.     

From the Cover: Parasitism alters three power laws of scaling in a metazoan community: Taylor’s law,density-mass allometry,and variance-mass allometry

How do the lifestyles (free-living unparasitized, free-living parasitized, and parasitic) of animal species affect major ecological power-law relationships? We investigated this question in metazoan communities in lakes of Otago, New Zealand. In 13,752 samples comprising 1,037,058 organisms, we found that species of different lifestyles differed in taxonomic distribution and body mass and were well described by three power laws: a spatial Taylor’s law (the spatial variance in population density was a power-law function of the spatial mean population density); density-mass allometry (the spatial mean population density was a power-law function of mean body mass); and variance-mass allometry (the spatial variance in population density was a power-law function of mean body mass). To our knowledge, this constitutes the first empirical confirmation of variance-mass allometry for any animal community. We found that the parameter values of all three relationships differed for species with different lifestyles in the same communities. Taylor''s law and density-mass allometry accurately predicted the form and parameter values of variance-mass allometry. We conclude that species of different lifestyles in these metazoan communities obeyed the same major ecological power-law relationships but did so with parameters specific to each lifestyle, probably reflecting differences among lifestyles in population dynamics and spatial distribution.Variation in population density has long been a central topic in ecology (e.g., ref. 1). Taylor’s law (TL) (2, 3) is a pattern of variation that has been widely verified for population density in basic and applied ecology and for other quantities in other fields. In its ecological interpretations, TL asserts that, in multiple sets of populations, the sample variance in population density within each set is proportional to a power (usually positive) of the sample mean population density within that set. We specify TL in greater detail below.Morand and Guégan (4) showed that TL described well the variations of abundance per host in 828 populations of parasitic nematodes from 66 terrestrial mammalian species. Morand and Krasnov (5) reviewed examples of TL in parasitology and epidemiology and interpreted the exponent of the TL power law in terms of the aggregation of parasites and epidemiological dynamics. These studies used the number of individual parasites per individual host as the measure of population density. Following a suggestion of Taylor (2), these studies interpreted the exponent of the power-law relationship of variance of population density to mean of population density as an index of parasite aggregation among hosts. A purely random distribution of parasites per host leads to a Poisson distribution, which gives a TL exponent equal to 1 as the mean population density varies. A TL exponent greater than 1 reflects greater heterogeneity in numbers of individuals per host than expected from a purely random distribution. More importantly, the TL exponent may also be used to assess the strength of parasite population regulation via processes such as interspecific competition or vaccination, and may distinguish between epidemic and endemic infections (5–7).Here we ask how three lifestyles (free-living unparasitized, free-living parasitized, and parasitic) of animal species affect major ecological power-law relationships, including TL, using new data on all metazoans from the littoral zone of four lakes in coastal and central Otago, South Island, New Zealand. Unlike previous studies of TL in parasitology, we measured the population density of parasites as the number of individuals per square meter of habitat, not per individual host. Additionally, unlike previous studies, in addition to quantifying the population density of parasitic species (separately for each life stage), we quantified the population density of the free-living parasitized species and of the free-living unparasitized species in the same habitat. Contrasting TL and other power-law relationships among organisms with different lifestyles can reveal differences in the degree to which spatial heterogeneity in their abundance is regulated.Using these data, we tested the validity of TL for metazoans of each lifestyle in the same habitat. Intuitively, it seemed plausible, and we investigated the hypothesis, that the interactions of free-living parasitized species and parasites added variability to the population dynamics of species of both lifestyles compared with free-living unparasitized species. This qualitative argument led us to expect larger values of the exponent of TL for free-living parasitized species and parasites compared with the exponent of TL for free-living unparasitized species.In addition to testing TL and the effects of lifestyle on the parameters of TL, we examined the allometric relationship between mean population density and mean body mass (density-mass allometry, or DMA). Marquet et al. (8) and Cohen et al. (9) independently showed theoretically that TL and DMA combine to predict the form and parameters of an allometric relationship between the variance of population density and mean body mass (variance-mass allometry, or VMA). (The details of these predictions are in SI Appendix.) We tested and verified all three relations empirically for each lifestyle in the same habitat. The parameter values of all three relationships depended on lifestyle.Although DMA has been very widely confirmed for a great variety of organisms (e.g., refs. 10–18), including parasitic nematodes (19) and other parasites (20), VMA has previously been confirmed empirically only for congeneric trees (Quercus spp.) in a temperate forest (9). These new data permitted us to verify the predicted VMA empirically, to our knowledge for the first time for any animals and for the first time for all metazoans in a local community. Empirical confirmation of VMA for all metazoans in a local community makes it possible to use average body mass to predict the variability of population densities of different species, in addition to predicting the mean population density from DMA. This variability bears on risks of extinction, population outbreaks, and epidemics. The ability to predict this variability from a factor as easily measured as average body mass could be valuable for economically important species.