A method for the detection of Shigella in foods was evaluated. The method consisted of selective enrichment at 37 degrees C in GN-broth supplemented with novobiocin (10 micrograms/ml) followed by subculture after 6 and 24 h incubation of 0.1 ml volumes to SS-agar with and without streptomycin (7.5 micrograms/ml). Test samples were contaminated by adding shigellae to 1:10 suspensions of foods (minced meat, fresh cut vegetables and cooked peeled shrimp) in the GN-broth with novobiocin. Shigella could be detected at a contamination level of 1 per 25 g in the presence of shrimp (in all 20 samples) and at 25 per 25 g in the presence of nearly all samples of fresh cut vegetables (in 13 out of 18 samples). Using this procedure Shigella could not be detected when the organism was present at a relatively high contamination level of 10(2) per 25 g in the presence of minced meat (with all 10 samples). However, the procedure described is an improvement on methods currently available for the detection of Shigella in foods.
In a longitudinal study over a period of ten weeks, the water conduit systems of seven dental surgeries with a total of 20 dental units in which legionellae had been detected in an earlier study (3) were investigated as a complement to extended microbiological tests (4) for the occurrence of free-living amebae and other protozoa. In 96% of all water samples, one or several ameba species were detected. These included 14 strains of the genus Naegleria, but no acanthamoebae. The naeglerias isolated were not thermophilic and thus belong to the N. gruberi complex, which does not contain any pathogenic strains. In two water samples, two different species of small freeliving nematodes were demonstrated. The simultaneous investigation of samples from the warm water supply in the individual dental surgeries revealed an ameba contamination in 24.9% of the samples. A nonpathogenic strain of the genus Protacanthamoeba was demonstrated once. The possible role of the trophozoites of various ameba species as hosts for an intracellular proliferation of the legionella strains demonstrated at the same time (cf. 4) is discussed. The occasional protective intracellular inclusion of legionellae in trophozoites of various species and in cysts of acanthamoebae might be an explanation for the resistance of legionellae to disinfection measures which has been repeatedly observed. This observation will have to be taken into consideration in sterilization and disinfection projects.
The investigation was intended to analyse the attitude towards hygiene and cleanliness in the Federal Republic of Germany, France, and Spain. On the basis of a theoretical explanatory model and empirically gained qualitative raw data a standardized questionnaire was prepared; in a number of questions comparability with a study carried out in the Federal Republic of Germany in 1968 was ensured. In all countries the population was subjected to representative random tests (Federal Republic of Germany n = 1016; France n = 517; Spain n = 514). The paper presents a review of the hypothesis that quality and intensity of the cleanliness increases with (1) the extent of personal sensitivity to hygiene in the private, professional and public sphere, (2) with increasing physical sensibility, (3) the increase in our knowledge of hygiene and health, (4) with the increase in the personal behavioral standards for measures concerned with prevention, hygiene of the body, household, underwear and environment, (5) with the increasing weight given to hygiene and toilet during the process of development, and (6) with the extent of regular control of education in cleanliness based on established rules of behavior. The spheres of behavior investigated and mentioned below confirmed the validity of the hypothesis for (1) household hygiene (spring-cleaning, window cleaning, cleaning of the home: dusting, vacuum-cleaning, cleaning of the floor), (2) hygiene of the body (frequency of taking a shower, bathing, toothbrushing, intimate hygiene), (3) hygiene of the laundry (frequency of changing underclothes such as panties/underpants, brassieres, nightgowns/pyjamas, stockings/socks, linen, pillows, dish and kitchen towels). The following general findings were established: (1) In the Federal Republic of Germany the attitude towards hygiene and cleanliness has improved over the last 20 years. (2) The level of hygiene and cleanliness in France and Spain is significantly higher than in the FRG. (3) The use of regular and also strict parental controls of the child's attitude towards cleanliness, as well as the continuity and systematic pursuance of this hygiene-orientated education is far more spread in France and in Spain than in the Federal Republic of Germany. (4) Within the population of a country differences are attributable to the quality of the parental educational efforts, to the importance of sex-specific cleanliness and toilet standards, to the knowledge of or the prejudices against the interrelationship between hygiene, cleanliness and health, the degree of private, public and professional hygiene sensibility, and physical sensibility.(ABSTRACT TRUNCATED AT 400 WORDS)
Permissible conclusions both from recent available literature and our own field-study results concerning the problematic nature of microbial contamination of dental hygiene articles and the resulting possible health hazard for the consumer can be summarized as follows: Manufacturing practices as are given in the basic instructions for production sites of the cosmetic industry, render a possible degree of microbial contamination. This largely rules out the danger of infection of the consumer upon acquisition of the dental hygiene product. Secondary contamination of these products, as inevitably is the case during use of dental hygiene articles, leads to microbial colonization especially of toothbrush bristles. The extent of this colonization depends at least partially upon the utilization age of the toothbrush. Also for this reason a toothbrush should be replaced by a new one after period of three months, six months at the latest and in all cases of inflammatory changes of the mouth and throat region. The contamination of both the glass or plastic container used for rinsing the teeth after brushing or for gargling can be held within certain limits by dry storage. Only in exceptional cases do mouthwashes show a small degree of contamination. Provided they contain antimicrobial substances, no therapeutically serviceable possibilities worth mentioning follow for the reduction of oropharyngeal flora. Microbial colonization of toothpastes as a result of secondary contamination following use is observed only in exceptional cases due to their preservative content. Significant germination of stagnated residual water in waterpicks often occurs, achieving germ counts up to more than 10(7) cfu per ml. Moreover, waterpicks can represent a biotope for Pseudomonas aeruginosa, and should be used neither by patients with open wounds or mucous membrane lesions in the oropharyngeal area, nor by patients with reduced immune resistance. Manufacturers of waterpicks are urged to impede or prevent the stagnation of residual water more effectively by introducing constructive improvements. Denture and retainer cleansing agents presently on the market display a sufficient antimicrobial effect within the frame of their application, however do not meet the standards set for disinfectants. Dental hygiene products are without relevance for the epidemiology of Legionnaires' disease.
Health and spoilage hazards arising from refrigerated and deep frozen foods may be due to - raw materials, e.g. pathogenic microorganisms which come from infected living animals or contaminate raw foods during handling. Psychrotrophic organisms have particular significance as pathogens or spoilage organisms as they can multiply also during refrigeration; - improper processing. Temperature abuse and incorrect time/temperature relations are main causes for microorganisms being not destroyed at the expected rate or even getting a chance of multiplying. Proper handling after refrigeration or frozen storage of foods ("hygiene of thawing") deserves also particular attention. - contamination, i.e. initial contamination of raw products which are ready for consumption without further processing (fruits, raw salads). Recontamination which follows a heat process is much more important and occurs before, during and after application of cold. In those cases, again, one has to distinguish between products which (a) are ready for consumption without a process (bakery and confectionary goods, ice cream, drinking milk) and (b) have to pass a process which reduces the bacterial load before consuming the food (ready to eat dishes or other foods ready for reheating in the home). Sites of increased hygienic hazard are a) lack of partitioning "clean" and "unclean" areas and processes, b) defects of sanitation and hygiene of personnel, c) defects of packaging, d) leakage during aseptic filling. Hazards are controlled through product and plant specific analysis of the process flow followed by continuous monitoring the "Critical Control Points". As an example, a report is given on a study on random samples taken from 180.000 prepackaged deep frozen menus which had been produced for a mass meeting. Microbiological monitoring of the process revealed time/temperature relations as critical control points of primary importance. Particular problems arose from any stoppage at the production line. Reliable means to assure food safety and protect consumer's health are HACCP concept based in plant control programs rather than sporadic microbiological monitoring of end products.
The family household belongs without doubt to the oldest social institutions of the history of mankind. If there were collecting and hunting tribes or already settled farmers, in every case the manufacturing, conserving and preparing of the hunted or gathered nutrition was always the focus of the household attention. Naturally next to it problems of clothing and heating played in this connection an important role. Very soon special instruments were developed for these purposes of production and workmanship by men and the advantages or disadvantages of certain proceedings were evident. As concerned the medico-historical view one can discern four different ways of consideration of domestic hygiene: 1. Mystical-magical conceptions, which started from the ideas of the influence of foreign partially supernatural powers on manufacturing and conserving of food. 2. The idea of the disastrous influence of an whatever supposed intoxication. 3. With the beginning of bacteriology the opinion even in general public of the contamination of foods and at last 4. The fear before a radiation contamination, which grew up recently with an increased importance. For all four considerations there will be put forward historical examples and beyond this it will be examined the influence of kitchen instruments and the increased automatic control in the household. But in parallel connection the increased knowledge of hygienic basic conditions and the application in the household area will be discussed. Shortly the changed part of the woman in household will be mentioned and its importance as concerned housekeeping in past and present will be demonstrated.
Findings of one year under review concerning food investigations carried out by the official food control of Baden-Wüttemberg are presented. This study is to demonstrate that, taking more samples, does not consistently mean improvement concerning the microbiological situation of food. A high percentage of the taken samples had to be confiscated because of the detection of pathogenic and facultative pathogenic germs being microbiologically inadmissible contaminants. The necessity of having a uniform judgement on microbiological food investigations is demonstrated. The study group "Food Hygiene" of the DGHM worked out examples related to instant products, raw dehydrated farinaceous pastes, cooking products, dehydrated soups, dehydrated one-dish meals, dehydrated sauces and spices. These examples are demonstrated. The problematic nature of a critical judgement is discussed.
Knowledge about bacterial foodborne diseases has broadened over the last 15 years. To this development have contributed improved isolation and identification methods but also the application of systematic epidemiological studies. In principle, no "new" bacteria have been discovered but their occurrence in foods was not known (e.g. Campylobacter jejuni/coli) or their detection in foods could not be firmly linked with disease in man (e.g. Listeria monocytogenes, E. coli O157:H7). For campylobacteriosis, listeriosis and yersiniosis foods are considered to be the main source of infection. Many of these "new" agents cannot only be detected in diseased, but also in healthy man and the environment. Frequently importance of foods as source of infection can only be proved by epidemiological studies. Traditional isolation and identification procedures are not sufficient to differentiate between virulent and avirulent strains. Molecular genetic methods as applied for e.g. enterotoxigenic E. coli allow the detection of virulence factors, however, in many instances relationship is lacking between the frequency of detection of a certain strain in food and clinical manifestation of disease. In particular, the recent listeriosis problems reveal the importance of individual host defence mechanisms and infectious doses for the evaluation. These aspects challenge the ideal complete absence (i.e., zero tolerance) of a certain microorganism in a specific food.)
Approximately 8 million pet birds are kept in the Federal Republic of Germany. The number of households where these birds are living is insignificantly lower, and the birds are usually kept as singles. Hygienic problems can arise due to the close contact between humans and birds. In view of the different pet birds species originating from different biotopes, specific knowledge is often lacking regarding adequate housing, nutrition and general management. This can result in a decrease of natural resistance and therefore can lead to diseases of those birds. Therapy, performed by a nonveterinarian, usually does not only affect the birds, but also endangers the owners themselves. Especially, the carrier state of newly purchased birds with pathogens hazardous for human health has to be considered. Psittacosis has to be mentioned as one of the major zooanthroponoses deriving from birds. This requires to reconsider governmental measures to cope with this disease including policies of bird import as one of the major reasons for spreading the disease. Better management conditions can extend the life expectation of birds. This might also lower the fluctuation within the pet bird population and therefore biohazards for humans. Therefore, instruction and advice of pet bird-owners are necessary.
The results of epidemiological investigations justifies the assumption that increasing health defects, especially enteritis infectiosa, are caused inter alia by inadequate hygienic conditions in households. The number of such diseases ranges between 100,000 and more than 1,000,000 cases per year in the FRG. Responsible for this development is a lack of information about the behaviour of microorganisms in the environment and its pathways of distribution. In addition risks are growing with the recommendation of cleansing methods, which had been adequate for the kitchen techniques in former centuries, but must fall under the conditions of the modern supply, processing and conservation. The described investigations are directed at the determination of the distribution of germs by working in normal household kitchens and at the effectiveness of surface-decontamination-cleansers (so-called FD-preparations). Test principle was the production of a complete dinner by each of 79 housewives with use of minced meat, which was contaminated with micrococcus luteus. After final cleaning of the kitchen we determined the degree of contamination of surfaces, machines and of the components of the meal with use of rodacplates, swabs and quantitative cultures respectively. The experiments are completed by interviews with the housewives. The results let conclude that the use of household cleansers with germicidal properties even in the hand of housewives will reduce the distribution of unwanted microorganisms in the kitchens. In this respect surfaces, on which components of the meal are prepared, and the machines, like cutting machines, waring blenders a.o., are of utmost importance. Disinfections of other parts of the flats including toilets are unnecessary (exception: severe infectious diseases). Therefore the use of FD-preparations outside of the kitchens is not required, but acceptable (it is not necessary to use a cleanser in the kitchen, another one in the toilet and a third one for the bath tube etc.). We do not recommend adapting cleaning and disinfective methods of the hospitals to the normal households. Instead of medical disinfections one should use detergents with nontoxic germicidal additives (e.g. H2O2) in this area, which do not require changing the traditional cleaning techniques. They also should guarantee that cleanliness, absence of odor and minimization of germs are achieved. In addition normal kitchen soaps should be replaced by HD-preparations.
In Germany, the last period of the Second World War and the following years were characterized by deficiencies of hygiene which had not occurred previously in Middle Europe during the 20th century. There were focuses of typhus, typhoid fever, tuberculosis, diphtheria, scarlet fever, and meningitis. Insufficiencies in the removal of faeces caused high incidences of shigellosis, hepatitis A, and ascariasis. As a result of insufficient body care, many people were infested with fleas, lice and scabies. The migration of large proportions of the population resulted in an increasing prevalence of syphilis an gonorrhea. As the population resettled, the first steps towards reorganization of public health could be done. The spread of typhoid fever was controlled by drinking-water disinfection with chlorine, repair of sewage systems, and patient isolation. The application of DDT helped to reduce scabies and pediculosis, resulting in decreasing typhus risks. During the first two decades after the war, there was a steady decrease of the incidence of infectious diseases. The reconstruction of the towns resulted in improved housing conditions and a decreasing number of persons per housing area, reducing the intensity of physical contacts of the inhabitants with each other. The nutrition and clothing situation of the population improved, which, in addition to a general rise of the standards of hygiene, brought about an increase of the individual resistance to infection. A further reduction of sporadic and epidemic outbreaks of infectious diseases was achieved by the introduction of chemotherapy and antibiotics. Increasing prosperity was accompanied by new problems of hygiene. Infectious diseases almost eradicated in West Germany, were imported by air travellers. Ten imported cases of smallpox were reported between 1957 and 1972, eight of which originated from Southeast Asia. Malaria, imported by German and foreign soldiers, had not been uncommon after the end of the war but had been easy to control by insecticides and antimalarials. As tourism expanded, a new wave of imported malaria cases was reported. In West Germany there is, however, no more spread of the disease under present conditions, cholera caused similar problems. The 1961 cholera epidemic started in Southeast Asia and caused minor outbreaks in Mediterranean countries like Italy and Spain. A significant spread of the disease throughout Europe was prevented by generally high standards of drinking water and sewage treatment. Sporadic cases of typhoid fever were imported from countries with low standards of hygiene.(ABSTRACT TRUNCATED AT 400 WORDS)
According to the drinking water regulations which were modified in 1986 drinking water in FRG fulfills high standards. But there are still special needs for an additional processing of drinking water including --disinfection and removal of pyrogenous substances, --water softening, --removal of heavy metals and solvents, --removal of substances of bad taste. Methods actually used for processing of drinking water like disinfection, filtration, UV-treatment, exchange of ions, are described and the hygienic problems in connection with these methods are pointed out. Results of our own studies on water filtration systems and on contaminated water pipe lines in dental units are demonstrated. Our data obtained suggest that additional processing of drinking water should fulfill the following demands: --the need of processing should be confirmed strictly, --the methods used should be controlled according to their propagated effectiveness by independent specialists, --there should be a reasonable relation between operation costs and efficacy of processing system, --there should be no loss of quality of drinking water during processing with the risk of induction of infection or intoxication in man.
In view of the risk of infection of the dentist and his staff in the dental surgery and dental laboratory and also of the patient with regard to hepatitis B and potentially also of AIDS, interruption of possible chains of infection by means of specific disinfection measures is to be demanded. Whereas appropriate hygiene concepts exist for disinfection of instruments, surfaces of equipment and furniture with regard to selection and application of various methods which may be considered, there are still extensive deficits for the domain of impression materials and their possible decontamination. In this regard, dentists frequently lack information with an adequate scientific basis that is understandable and oriented to practical requirements. Owing to the diversity of materials and their different behavior (cf. Tab. 1), appropriate recommendations can only be made on the basis of extensive studies. We assume that a practically relevant procedure must meet the following requirements: 1) sufficiently high rates of bacterial reduction in accordance with the guidelines of the DGHM, 2) lack of alterations in the dimensions or surfaces of the materials, 3) universal applicability, 4) practicability within a time period which is acceptable for smooth operation of the practice, 5) can be employed without problems for the staff. The object of the report are bacteriological results and materials testing data for the application of various methods of disinfection to selected impression materials. To summarize, it can be stated with regard to the bacteriological results that disinfection of impression materials is possible with fulfillment of the criteria specified above, but that there is a pronounced dependence of the results on the product formulation of the disinfectant and also of the impression material (cf. Fig. 4 and 5). Investigations of the material-related effects of the disinfection measures showed that extrapolation of the findings from one group of materials to another is also not possible in this connection, and that moreover the materials used to produce the model must also be included besides the impression materials used (cf. Fig. 9). Accordingly, statements on the suitability of a disinfection procedure are present admissible at most for the respective combination of materials tested, which makes practical introduction problematical.
For the evaluation of health risks emerging from imported foods data can be utilized which result from national surveillance programmes of member states and which are summarized, e.g. in the WHO Surveillance Programme for Control of Foodborne Infections and Intoxications in Europe. Within this programme annual reports are published reflecting the situation in the various European countries. The epidemiological data allow for long term preventive measures to be developed in an attempt to minimize health risks resulting from foods. Within this programme an Early Warning System has been established to monitor and report on incidents of international concern. The Commission of the European Communities operates an Alert System on contaminated food articles which are in international or intracommunity trade. Thus countries shall be placed in a position to initiate without delay steps for the prevention of current health risks. It is the declared policy of the EEC to dismantle by 1992 all trade barriers between the member countries and thus complete the European domestic market. This situation will make impossible border controls for food within the Community. From that time on import controls will only exist towards so-called Third Countries at the outer border of the Community. The internal free trade with foods on the one hand and the shift of inspection and control measures on the other necessitate a reconsideration of traditional official food inspection procedures. This reorientation has to include risk evaluations and strategies for routine food inspection services as well as questions of judgement criteria for different articles of food, e.g. microbiological criteria, agreement on sampling plans and standardization of examination procedures which would have to be applied.
The objective of our investigation is to establish and explain the contamination of dental treatment units on the basis of a theoretical model, as well as to develop solutions to problems. In a first longitudinal study (6), facultatively pathogenic bacteria were identified in the operating water of dental units; the legionellae findings in screening were verified in a second longitudinal study with consideration of possible causal factors of bacteriological and parasitological nature. We took samples from the dental units and the water conduit system (cold and warm water in the dental surgery, cold water in front of and behind house internal accessory installations) in seven practices at ten measurement times over a period of ten weeks. Microbiological diagnostics were carried out with regard to the occurrence of legionellae, amoebae, pseudomonads and coliforms. The correlation between the metal content of the water and the occurrence of legionellae described in the literature caused us to determine the copper, zinc and iron content of the waters (according to standard German method, 1985). In addition, the physical-chemical parameters temperature, pH value, conductivity and oxidizability as well as the total hardness were determined. The findings in the first phase of the study could be confirmed both qualitatively and quantitatively in the second phase. However, a greater diversity of species was shown with regard to the occurrence of legionellae in connection with an enlarged sample. We were able to isolate free-living amoebae from all dental units, the identification of which was carried out in parallel to that of legionellae in the context of the second investigation (26). With a high variance of the contamination spectrum between the individual practices and the various units within each practice, generalization of the results is not possible; the findings are hence illustrated with examples from selected practices with consideration of the initial and interaction conditions.
Viruses of importance brought into the household or excreted by its members vary in their resistance and are decimated or even completely inactivated by natural environmental influences as well as by washing and cleaning. Steps to disinfect the household should be limited to specific indications and performed with virucidal compounds harmless to the environment. Naturally antiviral influences such as heat, UV-rays, sunshine, acids, the effectiveness of washing and cleaning procedures in the household and some selected strongly virucidal, but non-pollutant disinfectants are discussed.
An effective disinfection depends on the tested efficiency of commercial products. The recommendations given by producers must be justified by facts. As no official registration procedure exists in Germany, the results obtained by voluntary testing institutions of scientific or branch-specialized associations have to be considered. A remarkable progress could be achieved in that field in the last years. Established were precisely prescribed test methods for disinfectants for (1) hospitals, kitchen areas included, by the DGHM (Deutsche Gesellschaft für Hygiene und Mikrobiologie); (2) processing areas for food of animal origin, kitchen areas also included, by the DVG (Deutsche Veterinärmedizinische Gesellschaft); (3) the beverage, especially the brewing industry by the MEBAK (Mitteleuropäische Brautechnische Analysen-Kommission); and (4) milk producing establishments by the DLG (Deutsche Landwirtschaftsgesellschaft). Each test method requires a different volume of procedures. This paper demonstrates by comparing the test factors which results may be achieved. Also taken into consideration were the methods prescribed by AFNOR (French Standardizing Organization) and by a Commission of the European Council. A disinfectant to be applied in the food industry should meet the following requirements: it should be (a) effective under application periods shorter than usually recommended for hospital areas or animal husbandry; (b) tested on less and heavier protein-loaded areas; (c) tested also under low-temperature conditions; (d) classified by groups of food products, in order to minimize the amount of substance applied to avoid unnecessary residues. The most comprehensive results may be obtained by the methods of the DGHM, DVG and MEBAK. The most specific data are provided in the DVG-list, the DGHM-list offers a somewhat reduced amount of specifics and the DLG-list is limited only to that informations which serve as basis for a quality seal. More coordination between the different testing and evaluation procedures would be appropriate in order to allow a comparison of the same products judged for different areas of application. An official test proceeding seems not necessary in Germany as enough reliable data are available from the above indicated institutions.
For evaluation of antiseptics intended for use on mucous membranes various effects, as bactericidal and fungicidal but also bacteriostatic and fungistatic effects as well as other mechanisms, have to be considered. The application of antiseptics on the oral mucous membrane is indicated to prevent wound infections, bacteremia following surgical intervention, infection caused by injuries as for example prosthetic ulcers as well as it is indicated for prophylaxis and therapy of infections like colds and for prevention of exogenic dissemination of bacteria. The substances used essentially are PVP-iodine-solutions, cation-active compounds, organic mercury- and silver-compounds and hydrogen peroxide-solutions. It has to be taken into account, however, that the toxicological properties of these substances vary. To this day there exists no generally accepted test model for the evaluation of these mucous membrane antiseptics. Therefore a test-solution on the basis of chlorhexidine digluconate was examined with the help of a rinse- and a swab-method, respectively. The total bacterial counts and the number of alpha-haemolytic streptococci was determined. The rinse-method resulted in reduction factors of log 1.0 after 5 to 120 min and the swab-method--applied at the buccal mucous membranes--in reduction factors of about log 1.5 after 5 min and log 1.0 to 1.2 after 120 min. At the gingival margin of the front teeth reduction factors rose from log 1.55 after 5 min to log 1.85 after 120 min. Possibly this rise was due to an after-effect of the tested antiseptic in this region. For examination of antiseptics a combination of both test methods is recommended.
The GMP-Rules, which were formulated by the WHO in 1969, were passed into German national lay by April 1st, 1985 as "Betriebsverordnung für pharmazeutische Unternehmer". The aim of this law is to guarantee constant quality of medical supplies. The food producing industry is facing similar requirements formulated either within the Codex Alimentarius or within the Code of Hygienic Practice of FDA (General Requirements for Food Manufacture). The degree of realization for these concepts of quality assurance however is varying extremely between different areas of food production. The requirements with regard to buildings, production plants, process technology, distribution and personnel hygiene as well as the principles of the HAAC-concept are described using examples from soft cheese, milk powder- and sweets industry.
An overview of the most important infections which can be transmitted from humans to pet dogs and cats is presented. Two quite different sources of infection stand diametrically opposite each other: 1. The transmission of active human infections to dogs and cats and 2. the transmission of infectious agents by feeding raw meat, offal, unsterilized milk products, kitchen scraps and contaminated feedstuffs. Humans can be the source of the following infections: 1. Zoonoses with reciprocal modes of transmission, e.g. Campylobacter and E. coli infections, trichophyton and microsporum infections, reo-, parainfluenza-, adeno, rota- and corona infections. 2. Zoonoses in which the main direction of infection is human----animal, e.g. tuberculosis and influenza A. 3. Infections originally pathogenic to humans which meet an impasse in dogs and cats (blind alley hosts), e.g. herpes simplex, varicella-zoster, measles and Corynebacterium diphtheriae. Listeria, salmonella, campylobacteria, toxoplasma, fungi, yeasts and viruses are transmitted via feed. The most dangerous virus infection to be transmitted to cats and dogs via raw pork leftovers is Aujeszky's disease. The dog or cat, which is the last link in the infection chain, suffers an agonizing death. The other infections originating from feed must be assessed quite differently. They are links in infection chains, which spread pathogens and endanger the health of man and animal in turn. A typical example is toxoplasmosis. Man becomes infected via sporulated oocysts from feces. Pet cats mainly become infected via raw pork containing cysts.
