Classification systems and case definitions provide the foundations upon which clinical and epidemiological studies are based. The European Research Network on Congenital Toxoplasmosis acknowledged the lack of such a system or definitions within its field of interest and established a working group to address the issue. Congenital Toxoplasma gondii infection was defined as occurring in four separate patient groups: pregnant women, fetuses, infants, and individuals > 1 year of age. The likelihood of Toxoplasma gondii infection was separated into five mutually exclusive categories: definite, probable, possible, unlikely, and not infected. Inclusion within a specific category is dependent upon the case definition, which is in turn derived from criteria based on serological, parasitological, and clinical information. Notes are included within the classification not only to clarify the definitions, but also to improve the reliability and quality of diagnosis. The goal is to construct a system that encompasses all aspects of congenital toxoplasmosis, which is applicable to different countries and health services, suitable for large epidemiological studies, aids the diagnosis and management of individual cases, and lends itself to computerisation.

This study has been conducted, to estimate the distribution of Giardia and Cryptosporidium in German water supplies and the removal efficiency of surface water treatment plants for Giardia and Cryptosporidium by conventional treatment. Water samples from six surface water treatment plants in different parts of Germany were simoultaneously examined for Giardia and Cryptosporidium. Investigations for both parasites were carried out in the period from July 1993 until December 1995. The results confirmed the occurrence of Giardia and Cryptosporidium in surface and raw water, in intermediate steps after treatment, in back wash water, in the first filtrate and in final water. Giardia or Cryptosporidium or both have been found in 76.2% of the investigated raw water sources. The average number of the detected Giardia cysts was 88.2/100 1 (max. 1314/100 1), and the average number of Cryptosporidium oocysts was 116/100 1 (max. 1081/100 1). In the intermediate steps (including flocculation and several steps of filtration), Giardia or Cryptosporidium or both have been found in 33.3% (50/150) of the samples. 14.9% of drinking water samples (7/47) were positive for Giardia (max. 16.8/100 1) and 29.8% (14/47) were positive for Cryptosporidium (max. 20.8/100 1). Overall, Giardia and Cryptosporidium, or both were detected in 38.3% of the drinking water samples. The parasites have been found in nearly all of the investigated backwash water samples. The filtrate of a rapid sand filter was analysed immediately after filter backwashing during the ripening period of the filter. Good elimination results were obtained by optimizing relevant water treatment process, but a low flocculant dose following sudden variation in the raw water quality, causes a breakthrough of Cryptosporidium into the treated water. Although water treatment technologies are effective to remove Giardia and Cryptosporidium, the results clearly show that Giardia and Cryptosporidium evade the filter barries in the absence of visible treatment deficiencies and low turbitidy level, and contaminate final water.

A 25-year-old female patient presented with an isolated cervical lymph node enlargement several months after having returned from Spain and Latin America. She had no other signs or symptoms of disease. Leishmania infantum/chagasi was identified as the causative agent. With extended travel activities localized lymph node enlargement due to leishmanial infection should be included in the differential diagnosis of lymphadenopathy of unknown origin.

Reactivation of chronic toxoplasmosis resulting in Toxoplasma encephalitis (TE) is a common event in acquired immune deficiency syndrome (AIDS) patients. Conversion from Toxoplasma gondii bradyzoites to tachyzoites is a prerequisite for reactivation. Until recently, the study of stage conversion in human tissue was not possible due to the lack of antibodies that recognize stage-specific epitopes after long-term formaldehyde fixation. Using the combination of a polyclonal anti-T. gondii antibody, the cyst-stage-specific monoclonal antibody CC2, and a tachyzoite-specific polyclonal antibody (anti-SAG1, recombinant), we tried to demonstrate parasite differentiation in the brain tissue of 10 AIDS patients with clinically suspected TE. Double labeling of the stage-specific antibodies enabled us to demonstrate interconversion between tachyzoites and bradyzoites for the first time in human tissue. The study confirmed that the transformation process is nonsynchronous and that the manifestation of TE depends on the degree and site of tissue destruction caused by invading tachyzoites. The original source of tachyzoites could never be located, but a few samples suggested that tachyzoites may invade by dissemination across the blood-brain barrier. Cyst rupture as the first event in the process of reactivation was not seen. We conclude that the initial site(s) of reactivation will be destroyed by tissue-destructive tachyzoites long before clinical symptoms occur.

After a release of genetically modified organisms, monitoring of potential adverse effects on the environment is mandatory. The protocol used for monitoring should be previously tested in practical studies and must be standardised. Moreover, sampling methods and the evaluation of results must meet current scientific and technical standards. Due to their particular role in maintaining soil quality and in a multitude of ecological processes in agro-ecosystems, soil organisms belong to those groups for which VDI guidelines are being developed. The guideline 4331 Part 1 describes fundamental criteria for the selection and sam- ReSeARCh ARtiCle BioRisk A peer-reviewed open-access journalAndrea Ruf et al. / BioRisk 8: 73-87 (2013) 74 pling of soil organisms for GMO monitoring and gives guidance for sampling design, sampling strategy and statistical evaluation. In the guideline three approaches are followed: (1) a compilation of previously known effects and exposure pathways, (2) a documentation of ecological functions of soil organisms (ecosystem services) as well as (3) a description of characteristic species compositions in the soil. The aim was to develop a selection matrix that helps to choose the appropriate animal groups to be sampled. Besides the habitat type and the ecological relevance, the selection matrix also considers the suitability of animal groups in terms of practical issues and, in specific cases, anticipated effects. Further parts of the guideline 4331 will describe sampling methods for relevant soil animal groups.