Impact of climate change on foodborne infections and intoxications.

Background: Temperature, precipitation, and humidity are important factors that can influence the spread, reproduction, and survival of pathogens. Climate change affects these factors, resulting in higher air and water temperatures, increased precipitation, or water scarcity. Climate change may thus have an increasing impact on many infectious diseases. Methods: The present review considers those foodborne pathogens and toxins in animal and plant foods that are most relevant in Germany, on the basis of a selective literature review: the bacterial pathogens of the genera Salmonella, Campylobacter and Vibrio, parasites of the genera Cryptosporidium and Giardia, and marine biotoxins. Results: As climate change continues to progress, all infections and intoxications discussed here can be expected to increase in Germany. Conclusions: The expected increase in foodborne infections and intoxications presents a growing public health risk in Germany.

Investigation and response to a large outbreak of leptospirosis in field workers in Lower Saxony, Germany.

Between June and August 2014, 45 cases of leptospirosis were notified among workers on two strawberry farms in North-West Germany. We describe the characteristics of the outbreak and the actions taken to prevent further cases. The activities of the local, federal and national public health and veterinary authorities included collection of case data, laboratory testing of human specimens and of small mammals trapped on the fields, investigation of weather data, as well as information provided to farmers, field workers, physicians and to the authorities in Poland and Romania. Of the 45 identified cases (median age 22, 60% male), 47% were hospitalized. Characteristic symptoms were fever ≥38.5°C, generalized muscle pain and an increase in renal or liver enzymes. Thirteen cases were laboratory confirmed by serological and/or molecular methods. ELISA tests for Leptospira IgG and IgM-antibodies were positive in those samples taken >5 days after hospitalization. The probable causative agent was identified as Leptospira kirschneri serovar Grippotyphosa. Leptospira-specific DNA was found in kidneys of 67% of 64 trapped small mammals and was further identified as Leptospira kirschneri multi locus sequence type 110. During the estimated time period of human infections, the affected region faced warm weather with heavy rainfalls. The results of this investigation are in accordance with the theory of a chain of infection from mice to field workers during warm and humid weather. In 2015, a campaign was initiated to inform physicians, farmers and workers to enhance prevention measures, such as the use of personal protective equipment and early consultation of physicians in case of illness. Since then, no further outbreak occurred.

Cause and Effect Analysis between Influencing Factors Related to Environmental Conditions, Hunting and Handling Practices and the Initial Microbial Load of Game Carcasses.

Environmental, hunting and handling factors affect the microbial load of hunted game and the resulting meat products. The aim of this study was to systematically investigate the influence of several factors on the initial microbial load (IML) of game carcasses during the early hunting chain. Eviscerated roe deer body cavities (n = 24) were investigated in terms of total viable count and the levels of Pseudomonas spp., Lactobacillus spp., Enterobacteriaceae and Escherichia coli (E. coli). Furthermore, a risk analysis based on the obtained original IML data, literature search and a Failure Mode and Effects Analysis (FMEA) was performed. The IML could be explained in a regression model by factors including the higher body weight (BW), damaged gastrointestinal tract by the shot, ambient temperature or rain. The levels of Lactobacillus spp. (p = 0.0472), Enterobacteriaceae (p = 0.0070) and E. coli (p = 0.0015) were lower on the belly flap surface when gloves were used during evisceration. The literature search revealed that studies examining influencing factors (IF) on the IML of game carcasses found contradictory effects of the comparable IF on IML. Potential handling failures may lead to a higher IML of game carcasses during the early hunting chain ranked by FMEA. Several handling practices for game carcasses are recommended, such as ensuring efficient cooling of heavier BW carcasses to limit bacterial growth or eviscerating heavier carcasses before lighter ones.

[Hepatitis E virus-a zoonotic virus: distribution, transmission pathways, and relevance for food safety]. / Das Hepatitis-E-Virus ­ ein zoonotisches Virus: Verbreitung, Übertragungswege und Bedeutung für die Lebensmittelsicherheit.

The hepatitis E virus (HEV) is an etiological agent of acute hepatitis in humans. In addition, chronic infections resulting in fatal liver cirrhosis currently emerge in immunosuppressed transplant patients. The number of notified hepatitis E cases in Germany has steeply increased in recent years. Here, genotype 3, which can be zoonotically transmitted from animals to humans, is predominant. The main reservoirs are pigs and wild boars, which show no signs of infection. In this article, the distribution of HEV in animals in Germany, possible transmission pathways, and especially the importance of food as a transmission vehicle are presented based on the current scientific literature.HEV is widely spread among domestic pigs and wild boars in Germany and the virus is mainly transmitted by direct contact or by consumption of food produced from those animals. However, if HEV RNA is detected in specific food it is often unclear whether the contained virus is still infectious or inactivated by the conditions during production. Recent studies indicate a high stability of HEV against different physicochemical conditions, whereas - among others - the virus can be efficiently inactivated by heating. Therefore, proper heating of pork meat and liver prior to consumption in general is recommended. For risk groups, avoiding shortly cured raw sausages is an additional suggestion.Further research is necessary to identify relevant risk food products, to investigate alternative transmission pathways, and to develop efficient measures in order to reduce or prevent zoonotic transmissions of the virus in future.

Reprint of: Survival of Trichinella spiralis in cured meat products.

Processing of meat is one possible approach to control meat-borne parasites. Processing methods such as freezing, cooking and irradiation are recommended for the control of Trichinella in pork, horse or game meat if specific technical conditions are fulfilled. Curing is a widely used preservation process influencing product characteristics such as shelf life, food safety, and taste. As curing methods are characterized by high parameter variability and predictions about inactivation of parasitic stages in raw meat products are difficult, curing and smoking are not recommended for Trichinella control. The objective of this study was to investigate the survival of T. spiralis in cured raw sausages taking into account water activity (aw-value), pH value, temperature, and time. For this purpose, four different types of sausage (Knackwurst, vacuum packed Knackwurst, short ripened salami, long ripened salami) were produced using T. spiralis infested batter. After production, the sausages were stored at product specific conditions for up to 35 days. During storage, pH value and aw-value of the sausages were monitored over time. Further, sausages of each type were digested using the magnetic stirrer method and the viability of the isolated larvae was assessed using a previously published larval motility test as a proxy for viability and infectivity of Trichinella larvae. In this context, we also introduce a three-level rated infectivity score (RIS) with a clear categorization scheme allowing the assessment of the infectivity of larvae. Based on the RIS, larvae isolated from the salamis were regarded as potentially infective until day 2 (short ripened salami) or day 3 (long ripened salami) post ripening, whereas in Knackwurst, potentially infective larvae were still found by day 8 post ripening. In contrast potentially infective larvae were detected in vacuum-packed Knackwurst until day 24 post ripening. Finally, using the RIS approach, data from previously published studies were collected and subjected to a correlation analysis to identify matrix factors linked to short Trichinella inactivation times.

Prevalence of Alaria alata mesocercariae in wild boars from Brandenburg, Germany.

Since 2002, Alaria (A.) alata mesocercariae (AM) have been found during routine Trichinella inspection of wild boars in many European countries. To date, human infection with AM through consumption of undercooked or raw AM infested wild boar meat cannot be excluded. In Germany, data on the parasite's prevalence in wild boars are scarce. To better understand temporal and spatial fluctuations of this parasite, this study investigated the prevalence of AM in wild boars in the German federal state of Brandenburg during three hunting seasons from 2017 to 2020. In total, 28.3% (100/354, 95% CI: 23.3-33.3%) of all wild boars sampled in eight counties of Brandenburg were tested positive for AM by Alaria alata mesocercariae migration technique (AMT). AM were detected in wild boars from seven different counties. Samples from one county (Havelland) tested completely negative for AM (0/16). Prevalences of the seven AM positive counties of Brandenburg ranged from 11.5 (3/26, 95% CI: 2.5-30.1%) in Märkisch-Oderland to 64.1% (25/39, 95% CI: 47.2-78.8%) in Uckermark. An association between sex and A. alata positivity could not be determined. A statistically significant increase in frequency of older AM positive wild boars was observed (p = 0.001). For a nationwide assessment of the prevalence of A. alata in wild boars and the risk for consumers of ingesting viable AM by consumption of raw or undercooked AM infested wild boar meat, further long-term studies in different regions of Germany are needed.

Survival of Trichinella spiralis in cured meat products.

Processing of meat is one possible approach to control meat-borne parasites. Processing methods such as freezing, cooking and irradiation are recommended for the control of Trichinella in pork, horse or game meat if specific technical conditions are fulfilled. Curing is a widely used preservation process influencing product characteristics such as shelf life, food safety, and taste. As curing methods are characterized by high parameter variability and predictions about inactivation of parasitic stages in raw meat products are difficult, curing and smoking are not recommended for Trichinella control. The objective of this study was to investigate the survival of T. spiralis in cured raw sausages taking into account water activity (aw-value), pH value, temperature, and time. For this purpose, four different types of sausage (Knackwurst, vacuum packed Knackwurst, short ripened salami, long ripened salami) were produced using T. spiralis infested batter. After production, the sausages were stored at product specific conditions for up to 35 days. During storage, pH value and aw-value of the sausages were monitored over time. Further, sausages of each type were digested using the magnetic stirrer method and the viability of the isolated larvae was assessed using a previously published larval motility test as a proxy for viability and infectivity of Trichinella larvae. In this context, we also introduce a three-level rated infectivity score (RIS) with a clear categorization scheme allowing the assessment of the infectivity of larvae. Based on the RIS, larvae isolated from the salamis were regarded as potentially infective until day 2 (short ripened salami) or day 3 (long ripened salami) post ripening, whereas in Knackwurst, potentially infective larvae were still found by day 8 post ripening. In contrast potentially infective larvae were detected in vacuum-packed Knackwurst until day 24 post ripening. Finally, using the RIS approach, data from previously published studies were collected and subjected to a correlation analysis to identify matrix factors linked to short Trichinella inactivation times.

Survival time of Leptospira kirschneri on strawberries.

In the past decade, two leptospirosis outbreaks occurred among strawberry harvesters in Germany, with 13, and 45 reported cases respectively. In both outbreaks, common voles (Microtus arvalis) infected with Leptospira kischneri serovar Grippotyphosa were identified as the most likely outbreak source. In an univariate analysis, eating unwashed strawberries was identified as one of the risk factors associated with Leptospira infection. The aim of this study was to evaluate the survival time of L. kirschneri serovar Grippotyphosa on strawberries under varying conditions. Strawberries were spiked with 5x109 of both a laboratory reference strain (strain Moskva V) and an outbreak field strain (94-6/2007) of L. kirschneri serovar Grippotyphosa sequence type 110. Survival times were investigated in a fully crossed design with three incubation times (2h, 4h, 6h and 8h) and three temperatures (15°C, 21°C and 25°C) with three replicated for each condition. A wash protocol was developed and recovered Leptospira were determined by qPCR, dark field microscopy and culturing. Viable L. kirschneri of both the reference strain and the field strain were identified in all samples at 25°C and an incubation time of 2h, but only 1/9 (11%) and 4/9 (44%) of the samples incubated at 15°C were positive, respectively. Both reference and field strain were viable only in 2/9 (22%) at 25° after 6h. After an 8h incubation, viable Leptospira could not be identified on the surface of the strawberries or within the fruit for any of the tested conditions. Based on these results, the exposure risk of consumers to viable Leptospira spp. through the consumption of strawberries bought at the retail level is most likely very low. However, there is a potential risk of Leptospira infection by consumption of strawberries on pick-your-own farms.

Seroprevalence of Toxoplasma gondii in wild boar and deer in Brandenburg, Germany.

Consumption of game in Germany has increased during the past 10 years. Wild boar (Sus scrofa), roe deer (Capreolus capreolus) and red deer (Cervus elaphus) are the most frequently hunted and consumed game animals in Germany, yet information on the occurrence of zoonotic pathogens in these animal species is scarce. To better estimate the public health risk emanating from handling and consumption of game, this study investigated seroprevalences of Toxoplasma gondii in game hunted in the German federal state of Brandenburg during two hunting seasons from 2017 to 2019. Toxoplasma gondii-specific antibodies were detected in 24.4% (44/180, 95% CI: 18.4%-31.4%) of wild boar, 12.8% (16/125, 95% CI: 7.5%-20%) of roe deer and 6.4% (3/47, 95% CI: 1.3%-17.5%) of red deer using a commercial ELISA kit. Seroprevalences were similar in the two hunting seasons. Correlation between sex and seropositivity could not be observed. A rise in seroprevalence was seen with increasing age in all studied game species. Observed seroprevalences suggest that T. gondii is endemic in the sylvatic environment in the German federal state of Brandenburg and imply that game could represent a relevant source for human T. gondii infection.

[Leptospirosis in Germany: current knowledge on pathogen species, reservoir hosts, and disease in humans and animals]. / Leptospirose in Deutschland: Aktuelle Erkenntnisse zu Erregerspezies, Reservoirwirten und Erkrankungen bei Mensch und Tier.

Leptospirosis is a zoonotic disease with a wide spectrum of clinical symptoms in humans and animals, ranging from subclinical infections to severe signs of multiorgan dysfunction. In Germany, laboratory confirmation of acute human infection is notifiable based on the Protection Against Infection Act. Disease or occurrence of the pathogen in pigs and sheep must be reported according to the regulation on reportable animal diseases. Transmission occurs via direct and indirect contact with the urine of infected animals, with rodents acting as the main reservoir. With an average annual incidence of 0.1 notified cases per 100,000 inhabitants, leptospirosis is a rare disease in Germany.This review article presents the current knowledge on leptospirosis in Germany in the framework of the project "Improving public health through a better understanding of the epidemiology of rodent-transmitted diseases" (RoBoPub) funded by the Ministry of Education and Research. In a One-Health approach, information about clinical manifestation, available prevalence data in humans and animals, knowledge of pathogen distribution, host association, mode of transmission, and survival in the environment is summarized. Preliminary findings on the influence of fluctuations in rodent populations on the occurrence of leptospirosis are also discussed. The aim of the article is to increase the awareness of this currently neglected disease in Germany.In future, higher temperatures and more frequent heavy rainfalls, which could occur due to climate change, should be taken into account.

Leptospira spp. in Rodents and Shrews from Afghanistan.

Leptospirosis is an occupational risk for military personnel and many cases have been reported worldwide. Rodents are the most important maintenance hosts for Leptospira spp. and may infect both animals and humans. To determine the occurrence and identity of pathogenic Leptospira spp. in rodent and shrew populations in German military camps in Afghanistan, we examined 751 animals ( Mus musculus, Cricetulus migratorius, Meriones libycus, Rattus tanezumi, Crocidura cf. suaveolens, and Suncus etruscus) from four military camps in Northern Afghanistan from 2009-12. Leptospiral DNA was found in 1.1% of the animals and only in Mus musculus. Partial secY sequencing identified Leptospira borgpetersenii and Leptospira kirschneri as infecting genomospecies. Multilocus sequence typing was successful in the L. borgpetersenii samples, which were identified as sequence type 155. The low prevalence we observed suggested that the exposure risk of military personnel to infectious Leptospira spp. in the region is low.

Performance of three molecular methods for detection of Toxoplasma gondii in pork.

Comparison of epidemiological data on the occurrence of Toxoplasma (T.) gondii tissue cysts in meat is hampered by the lack of standardization and a great variety of methods for molecular detection. Therefore, this study aimed to compare and validate three different polymerase chain reaction (PCR) methods for detection of T. gondii DNA in pork. Analytical performance characteristics of two real time PCRs (qPCRs; Tg-qPCR1, Tg-qPCR2) and one conventional endpoint PCR (cPCR), all targeting the 529 repeated element, were assessed using genomic DNA of three clonal T. gondii types prevailing in Europe and North America. qPCR efficiencies for all three clonal types ranged between 93.8 and 94.4% (Tg-qPCR1) and 94.3-95.6% (Tg-qPCR2). Tg-qPCR1 and Tg-qPCR2 showed an overall PCR performance score of 85% and displayed a similar 95% detection limit of 1.067 and 1.561 genome equivalents per PCR reaction (GE/PCR), respectively. However, T. gondii DNA could be detected at concentrations as low as 0.1 GE/PCR. Reliable quantification is possible over 4 log ranges from 105 to 100 GE/PCR with mean repeatability relative standard deviations of ≤11% and reproducibility relative standard deviations of ≤12.7%. Presumably, both qPCRs are similarly suitable for sensitive and specific detection of T. gondii DNA in pork. In contrast, the cPCR using primer pair TOX5/Tox-8 proved to be highly sensitive with a detection limit of 1.41 GE/PCR, but not suitable for detection of T. gondii DNA in pork as unspecific amplification of porcine DNA was observed resulting in bands with similar size to the desired T. gondii-specific PCR product.

Yersinia pseudotuberculosis Prevalence and Diversity in Wild Boars in Northeast Germany.

In this study, the prevalence of Yersinia pseudotuberculosis in wild boars in northeast Germany was determined. For that purpose, the tonsils of 503 wild boars were sampled. The presence of Y. pseudotuberculosis was studied by diagnostic PCR. Positive samples were analyzed by cultural detection using a modified cold enrichment protocol. Ten Y. pseudotuberculosis isolates were obtained, which were characterized by biotyping, molecular serotyping, and multilocus sequence typing (MLST). In addition, whole-genome sequences and the antimicrobial susceptibility of the isolates were analyzed. Yersinia pseudotuberculosis was isolated from male and female animals, most of which were younger than 1 year. A prevalence of 2% (10/503) was determined by cultural detection, while 6.4% (32/503) of the animals were positive by PCR. The isolates belonged to the biotypes 1 and 2 and serotypes O:1a (n = 7), O:1b (n = 2), and O:4a (n = 1). MLST analysis revealed three sequence types, ST9, ST23, and ST42. Except one isolate, all isolates revealed a strong resistance to colistin. The relationship of the isolates was studied by whole-genome sequencing demonstrating that they belonged to four clades, exhibiting five different pulsed-field gel electrophoresis (PFGE) restriction patterns and a diverse composition of virulence genes. Six isolates harbored the virulence plasmid pYV. Besides two isolates, all isolates contained ail and inv genes and a complete or incomplete high-pathogenicity island (HPI). None of them possessed a gene for the superantigen YPM. The study shows that various Y. pseudotuberculosis strains exist in wild boars in northeast Germany, which may pose a risk to humans.IMPORTANCEYersinia pseudotuberculosis is a foodborne pathogen whose occurrence is poorly understood. One reason for this situation is the difficulty in isolating the species. The methods developed for the isolation of Yersinia enterocolitica are not well suited for Y. pseudotuberculosis We therefore designed a protocol which enabled the isolation of Y. pseudotuberculosis from a relatively high proportion of PCR-positive wild boar tonsils. The study indicates that wild boars in northeast Germany may carry a variety of Y. pseudotuberculosis strains, which differ in terms of their pathogenic potential and other properties. Since wild boars are widely distributed in German forests and even populate cities such as Berlin, they may transmit yersiniae to other animals and crop plants and may thus cause human infections through the consumption of contaminated food. Therefore, the prevalence of Y. pseudotuberculosis should be determined also in other animals and regions to learn more about the natural reservoir of this species.

Leptospira Genomospecies and Sequence Type Prevalence in Small Mammal Populations in Germany.

Leptospirosis is a worldwide emerging infectious disease caused by zoonotic bacteria of the genus Leptospira. Numerous mammals, including domestic and companion animals, can be infected by Leptospira spp., but rodents and other small mammals are considered the main reservoir. The annual number of recorded human leptospirosis cases in Germany (2001-2016) was 25-166. Field fever outbreaks in strawberry pickers, due to infection with Leptospira kirschneri serovar Grippotyphosa, were reported in 2007 and 2014. To identify the most commonly occurring Leptospira genomospecies, sequence types (STs), and their small mammal host specificity, a monitoring study was performed during 2010-2014 in four federal states of Germany. Initial screening of kidney tissues of 3,950 animals by PCR targeting the lipl32 gene revealed 435 rodents of 6 species and 89 shrews of three species positive for leptospiral DNA. PCR-based analyses resulted in the identification of the genomospecies L. kirschneri (62.7%), Leptospira interrogans (28.3%), and Leptospira borgpetersenii (9.0%), which are represented by four, one, and two STs, respectively. The average Leptospira prevalence was highest (∼30%) in common voles (Microtus arvalis) and field voles (Microtus agrestis). Both species were exclusively infected with L. kirschneri. In contrast, in bank voles (Myodes glareolus) and yellow-necked mice (Apodemus flavicollis), DNA of all three genomospecies was detected, and in common shrews (Sorex araneus) DNA of L. kirschneri and L. borgpetersenii was identified. The association between individual infection status and demographic factors varied between species; infection status was always positively correlated to body weight. In conclusion, the study confirmed a broad geographical distribution of Leptospira in small mammals and suggested an important public health relevance of common and field voles as reservoirs of L. kirschneri. Furthermore, the investigations identified seasonal, habitat-related, as well as individual influences on Leptospira prevalence in small mammals that might impact public health.

Prevalence, Host Range, and Comparative Genomic Analysis of Temperate Ochrobactrum Phages.

Ochrobactrum and Brucella are closely related bacteria that populate different habitats and differ in their pathogenic properties. Only little is known about mobile genetic elements in these genera which might be important for survival and virulence. Previous studies on Brucella lysogeny indicated that active phages are rare in this genus. To gain insight into the presence and nature of prophages in Ochrobactrum, temperate phages were isolated from various species and characterized in detail. In silico analyses disclosed numerous prophages in published Ochrobactrum genomes. Induction experiments showed that Ochrobactrum prophages can be induced by various stress factors and that some strains released phage particles even under non-induced conditions. Sixty percent of lysates prepared from 125 strains revealed lytic activity. The host range and DNA similarities of 19 phages belonging to the families Myoviridae, Siphoviridae, or Podoviridae were determined suggesting that they are highly diverse. Some phages showed relationship to the temperate Brucella inopinata phage BiPB01. The genomic sequences of the myovirus POA1180 (41,655 bp) and podovirus POI1126 (60,065 bp) were analyzed. Phage POA1180 is very similar to a prophage recently identified in a Brucella strain isolated from an exotic frog. The POA1180 genome contains genes which may confer resistance to chromate and the ability to take up sulfate. Phage POI1126 is related to podoviruses of Sinorhizobium meliloti (PCB5), Erwinia pyrifoliae (Pep14), and Burkholderia cenocepacia (BcepIL02) and almost identical to an unnamed plasmid of the Ochrobactrum intermedium strain LMG 3301. Further experiments revealed that the POI1126 prophage indeed replicates as an extrachromosomal element. The data demonstrate for the first time that active prophages are common in Ochrobactrum and suggest that atypical brucellae also may be a reservoir for temperate phages.

Genetic Diversity of Brucella Reference and Non-reference Phages and Its Impact on Brucella-Typing.

Virulent phages have been used for many years to type Brucella isolates, but until recently knowledge about the genetic makeup of these phages remains limited. In this work the host specificity and genomic sequences of the original set (deposited in 1960) of VLA Brucella reference phages Tb, Fi, Wb, Bk2, R/C, and Iz were analyzed and compared with hitherto described brucellaphages. VLA phages turned out to be different from homonymous phages in other laboratories. The host range of the phages was defined by performing plaque assays with a wide selection of Brucella strains. Propagation of the phages on different strains did not alter host specificity. Sequencing of the phages TbV, FiV, WbV, and R/CV revealed nucleotide variations when compared to same-named phages previously described by other laboratories. The phages Bk2V and IzV were sequenced for the first time. While Bk2V exhibited the same deletions as WbV, IzV possesses the largest genome of all Brucella reference phages. The duplication of a 301 bp sequence in this phage and the large deletion in Bk2V, WbV, and R/CV may be a result of recombination caused by repetitive sequences located in this DNA region. To identify new phages as potential candidates for lysotyping, the host range and Single Nucleotide Polymorphisms (SNPs) of 22 non-reference Brucella phages were determined. The phages showed lysis patterns different from those of the reference phages and thus represent novel valuable candidates in the typing set.

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples.

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode larvae of the genus Trichinella. The most important sources of human infections worldwide are game meat and pork or pork products. In many countries, the prevention of human trichinellosis is based on the identification of infected animals by means of the artificial digestion of muscle samples from susceptible animal carcasses. There are several methods based on the digestion of meat but the magnetic stirrer method is considered the gold standard. This method allows the detection of Trichinella larvae by microscopy after the enzymatic digestion of muscle samples and subsequent filtration and sedimentation steps. Although this method does not require special and expensive equipment, internal controls cannot be used. Therefore, stringent quality management should be applied throughout the test. The aim of the present work is to provide detailed handling instructions and critical control points of the method to analysts, based on the experience of the European Union Reference Laboratory for Parasites and the National Reference Laboratory of Germany for Trichinella.

Survey for zoonotic pathogens in Norway rat populations from Europe.

BACKGROUND: The Norway rat Rattus norvegicus is an important reservoir of various zoonotic pathogens, such as cowpox virus and Leptospira, but also for agents of no or unknown zoonotic potential. We describe a survey of 426 Norway rats originating from five European countries and different habitats for Leptospira spp., rickettsiae, orthopoxvirus (OPV), avian metapneumovirus subtypes A and B (aMPV) and rat polyomavirus (rat PyV). RESULTS: Leptospira DNA was detected in 60 out of 420 (14.3%) rats, and Rickettsia DNA was found in three out of 369 (0.8%) rats investigated. PCR-based typing resulted in the identification of L. interrogans sequence type 17, which corresponds to the serogroup Icterohaemorrhagiae, and Rickettsia helvetica respectively. Rat PyV DNA was detected in 103 out of 421 (24.5%) rats. OPV DNA and aMPV RNA were detected in none of the rats, but OPV-specific antibodies were detected in three out of 388 (0.8%) rats. The frequency of single Leptospira and rat PyV infections and coinfections was, independent of sex, greater for adults compared with juveniles/subadults and greater at rural sites compared with urban areas. CONCLUSIONS: Study results indicate a broad geographical distribution of Leptospira DNA in rats within Europe, underlining the need to investigate further the potential mechanisms leading to increased prevalence in rural habitats and to assess the relevance to public health. In contrast, rickettsia and OPV infections rarely occurred in wild rat populations. The potential influence of rat PyV on the susceptibility to infections with other pathogens should be investigated in future studies. © 2016 Society of Chemical Industry.

First Report of the Occurrence of Trichinella-Specific Antibodies in Domestic Pigs in Central and Eastern Uganda.

Previous research on trichinellosis in Africa focused on isolating Trichinella from wildlife while the role of domestic pigs has remained highly under-researched. Pig keeping in Uganda is historically recent, and evidence on zoonotic pig diseases, including infection with Trichinella species, is scarce. A cross-sectional survey on Trichinella seroprevalence in pigs was conducted in three districts in Central and Eastern Uganda from April 2013 to January 2015. Serum from a random sample of 1125 pigs from 22 villages in Eastern and Central Uganda was examined to detect immunoglobulin G (IgG) against any Trichinella spp. using a commercially available ELISA based on excretory-secretory antigen. ELISA positive samples were confirmed using Western Blot based on somatic antigen of Trichinella spiralis as recommended in previous validation studies. Diaphragm pillar muscle samples (at least 5 g each) of 499 pigs from areas with high ELISA positivity were examined using the artificial digestion method. Overall, 78 of all 1125 animals (6.9%, 95% CI: 5.6-8.6%) tested positive for antibodies against Trichinella spp. in the ELISA at significantly higher levels in Kamuli district compared to Masaka and Mukono districts. Thirty-one percent of the ELISA positive samples were confirmed IgG positive by the Western Blot leading to an overall seroprevalence of 2.1% (95% CI: 1.4-3.2%). The large proportion of ELISA positive samples that could not be confirmed using Western blot may be the result of cross-reactivity with other gastrointestinal helminth infections or unknown host-specific immune response mechanisms in local pig breeds in Uganda. Attempts to isolate muscle larvae for species determination using the artificial digestion method were unsuccessful. Due to the large number of muscle samples examined we are confident that even if pigs are infected, the larval burden in pork is too low to pose a major risk to consumers of developing trichinellosis. This was the first large systematic field investigation of Trichinella infection in domestic pigs in Uganda and its results imply that further studies are needed to identify the Trichinella species involved, and to identify potential sources of infection for humans.

Risk factors for human Leptospira seropositivity in South Germany.

We analyzed risk factors for Leptospira seropositivity in humans, using data from a population-based cross-sectional zoonosis survey in South Germany (2008/9). Out of 1007 participants 42 (4.2 %) were sero-positive (19/446 men; 23/561 women), indicating that Leptospira exposure and sero-conversion is much more frequent than commonly assumed. Relative risks (RR) for seropositivity with exact 95 % confidence intervals (CI; adjusted for specificity and sensitivity of the ELISA test) were calculated for various exposure factors. Contact with pet rats (RR = 13.9 CI [4.8; 25.3]), guinea pigs (3.0[1.1; 7.4]), cattle (3.7[1.3; 9.6]), poultry (3.6[1.3; 8.6]) or livestock (2.3[1.1; 4.9]) as well as occupation as forestry worker (9.2[2.6; 21.4]) were identified as important exposure factors. None of the participants has ever been diagnosed with leptospirosis, yet 45 had experienced symptoms which may have been caused by Leptospira infection (12 with scleral icterus, 25 dark urine, 8 liver inflammation, 7 kidney failure). Three times as many participants with prior symptoms were seropositive as participants without symptoms (RR = 3.4[1.3; 8.3]), suggesting that sero-positive patients with severe symptoms may frequently not be diagnosed as leptospirosis cases. Physicians should consider leptospirosis as a differential diagnosis. Currently, the vast majority of symptomatic leptospirosis patients may neither be diagnosed nor reported.