Lactococcus lactis, causative agent of an endocarditis valvularis and parietalis thromboticans in the allis shad, Alosa alosa (L.)

Since the 1940s, the anadromous allis shad, Alosa alosa (L.), has suffered population declines throughout its distribution range in Europe. In context of EU-LIFE projects for the reintroduction of the allis shad in the Rhine system, a comprehensive study was started in 2012 to investigate infectious diseases occurring in allis shad. In course of the study, 217 mature and young-of-the-year allis shad originating from the wild population from the Gironde-Garonne-Dordogne system (GGD-system) and the Rhine system as well as 38 allis shad from the breeding population were examined by use of bacteriological and histological methods. In 2012 and 2014, an endocarditis valvularis thromboticans caused by a coccoid bacterium was detected in 16% and 25% of mature allis shad originating from the GGD-system. Results of microbiologic examinations, including biochemical characteristics, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequence analysis, revealed Lactococcus lactis as causative agent of this infection. This is the first report of an endocarditis valvularis and parietalis thromboticans caused by Lactococcus lactis in fish. Possible sources of infection as well as the impact for the reintroduction programme are discussed.

First report of a cystic malformation on the upper jaw of hatchery-reared allis shad Alosa alosa

The anadromous allis shad Alosa alosa has suffered dramatic population declines throughout Europe and is currently considered as endangered throughout its entire distribution range. In order to reestablish allis shad in the River Rhine, which formerly housed one of the largest and most important populations, an EU-LIFE Project 'The re-introduction of allis shad in the Rhine system' was started in 2007. In course of the LIFE+ Projects, allis shad larvae bred from genitor fish of the Gironde-Garonne-Dordogne population in France were reared in a pilot ex situ stock plant pilot facility in Aßlar, Germany. At an age of 1-2 months, about 100% of these fish developed approximately 0.5- to 0.8-cm large, fluid-filled, transparent cysts in conjunction with the upper jaw. The performed microbiological, virological, parasitological and histological examinations did not detect any infectious agents. Possible causative agents are discussed with regard to environmental factors and the nutrition of larvae. In conclusion, the observed malformations are considered a sign for a severe health problem and therefore a risk for the successful breeding of allis shad in aquaculture.

Repatriation of an old fish host as an opportunity for myxozoan parasite diversity: The example of the allis shad, Alosa alosa (Clupeidae), in the Rhine

Background

Wildlife repatriation represents an opportunity for parasites. Reintroduced hosts are expected to accumulate generalist parasites via spillover from reservoir hosts, whereas colonization with specialist parasites is unlikely. We address the question of how myxozoan parasites, which are characterized by a complex life-cycle alternating between annelids and fish, can invade a reintroduced fish species and determine the impact of a de novo invasion on parasite diversity. We investigated the case of the anadromous allis shad, Alosa alosa (L.), which was reintroduced into the Rhine approximately 70 years after its extinction in this river system.

Methods

We studied parasites belonging to the Myxozoa (Cnidaria) in 196 allis shad from (i) established populations in the French rivers Garonne and Dordogne and (ii) repatriated populations in the Rhine, by screening the first adults returning to spawn in 2014. Following microscopical detection of myxozoan infections general myxozoan primers were used for SSU rDNA amplification and sequencing. Phylogenetic analyses were performed and cloned sequences were analyzed from individuals of different water sources to better understand the diversity and population structure of myxozoan isolates in long-term coexisting vs recently established host-parasite systems.

Results

We describe Hoferellus alosae n. sp. from the renal tubules of allis shad by use of morphological and molecular methods. A species-specific PCR assay determined that the prevalence of H. alosae n. sp. is 100 % in sexually mature fish in the Garonne/Dordogne river systems and 22 % in the first mature shad returning to spawn in the Rhine. The diversity of SSU rDNA clones of the parasite was up to four times higher in the Rhine and lacked a site-specific signature of SNPs such as in the French rivers. A second myxozoan, Ortholinea sp., was detected exclusively in allis shad from the Rhine.

Conclusions

Our data demonstrate that the de novo establishment of myxozoan infections in rivers is slow but of great genetic diversity, which can only be explained by the introduction of spores from genetically diverse sources, predominantly via straying fish or by migratory piscivorous birds. Long-term studies will show if and how the high diversity of a de novo introduction of host-specific myxozoans succeeds into the establishment of a local successful strain in vertebrate and invertebrate hosts.

Graphical Abstract

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1760-6) contains supplementary material, which is available to authorized users.

[Focal meningitis in a California sea lion (Zalophus californianus)--diagnostic procedure and pathology]

A 15-year-old female California sea lion (Zalophus californianus) with progressive lameness of the hindlimbs and a chronic skin lesion was presented for clinical examination. The clinical neurological examination, showing a paraparesis, was completed by magnetic resonance imaging. MR images of the cervical and thoracic spine showed a well-defined muscle infiltrating lesion between the seventh cervical vertebra (C7) and the second thoracic vertebra (T2), which extended through the intervertebral foramina between C7 and T1 into the vertebral canal, causing spinal cord compression and displacement. Pathological examination revealed focal purulent meningitis resulting from widespread fistulas of the chronic skin leasion, which was infected with Escherichia coli var. haemolytica and Clostridium perfringens.

[Pathologic-anatomical changes in newborn goats caused by an intrauterine Schmallenberg virus infection]

A complex of various malformations in newborns was observed to an increased extent in sheep farms in the 2011/2012 lambing season. An intrauterine Schmallenberg virus (SBV) infection was identified as the cause of these malformations. To date, a detailed pathological description of the deformity complex has only been given for bovine and ovine newborns.The aim of this study was therefore to provide a description of pathologic-anatomical congenital malformations in goat kids caused by intrauterine SBV infection. To this end, pathologic-anatomical and molecular biological investigations by PCR were carried out on 37 goat kids and 457 lambs from 238 sheep and goat farms in order to carry out an interspecies comparison. Of the 37 goat kids dissected, it was possible to identify a SBV infection in twelve animals (32.4%) by RT-PCR. In nine animals (24.3%) displaying pathological-anatomical malformations SBV could not be detected by PCR. The following malformations were observed: athrogryposis, deformation of spinal column, torticollis, asymmetry of the skull, brachygnathia inferior, cerebellar hypoplasia, cerebellar aplasia and internal hydrocephalus. Arthogryposis was the most common malformation, both in animals with positive PCR results and those with negative PCR results. This study documents congenital malformations caused by an intrauterine SBV infection for the first time on a large number of newborn goats.

German Francisella tularensis isolates from European brown hares (Lepus europaeus) reveal genetic and phenotypic diversity

BACKGROUND

Tularemia is a zoonotic disease caused by Francisella tularensis that has been found in many different vertebrates. In Germany most human infections are caused by contact with infected European brown hares (Lepus europaeus). The aim of this study was to elucidate the epidemiology of tularemia in hares using phenotypic and genotypic characteristics of F. tularensis.

RESULTS

Cultivation of F. tularensis subsp. holarctica bacteria from organ material was successful in 31 of 52 hares that had a positive PCR result targeting the Ft-M19 locus. 17 isolates were sensitive to erythromycin and 14 were resistant. Analysis of VNTR loci (Ft-M3, Ft-M6 and Ft-M24), INDELs (Ftind33, Ftind38, Ftind49, RD23) and SNPs (B.17, B.18, B.19, and B.20) was shown to be useful to investigate the genetic relatedness of Francisella strains in this set of strains. The 14 erythromycin resistant isolates were assigned to clade B.I, and 16 erythromycin sensitive isolates to clade B.IV and one isolate was found to belong to clade B.II. MALDI-TOF mass spectrometry (MS) was useful to discriminate strains to the subspecies level.

CONCLUSIONS

F. tularensis seems to be a re-emerging pathogen in Germany. The pathogen can easily be identified using PCR assays. Isolates can also be identified within one hour using MALDI-TOF MS in laboratories where specific PCR assays are not established. Further analysis of strains requires genotyping tools. The results from this study indicate a geographical segregation of the phylogenetic clade B.I and B.IV, where B.I strains localize primarily within eastern Germany and B.IV strains within western Germany. This phylogeographical pattern coincides with the distribution of biovar I (erythromycin sensitive) and biovar II (erythromycin resistance) strains. When time and costs are limiting parameters small numbers of isolates can be analysed using PCR assays combined with DNA sequencing with a focus on genetic loci that are most likely discriminatory among strains found in a specific area. In perspective, whole genome data will have to be investigated especially when terrorist attack strains need to be tracked to their genetic and geographical sources.

Quantification of the herpesvirus content in various tissues and organs, and associated post mortem lesions of psittacine birds which died during an epornithic of pacheco's parrot disease (PPD)

This paper reports on the viral content of up to 52 tissue and organ samples of 18 individual large psittacines which died during an epornithic of Pacheco's parrot disease (PPD) caused by psittacid herpesvirus 1 (PsHV1). Associated clinical signs and pathological lesions are described. The large spectrum of samples found to be positive for PsHVl suggests that birds succumb to PPD during viraemia. Tissues and organs from which the virus could be isolated included the integument and associated structures, the muscular, respiratory and circulatory system, bone marrow, the nervous system, thyroid and adrenal glands, spleen and liver, the urogenital tract and the gastro-intestinal tract. Nevertheless, individual and organ (but not species)-specific variation does occur. Virus isolation appears to be most promising from the respiratory, vascular and nervous system and the liver. Highest titres were obtained from heart blood and liver (up to 7.6 log(10)/g tissue), airsac, Nervus vagus and pulp and quill of pin feathers. Pin feathers may therefore be suitable for in-vivo diagnosis. In contrast, HV could not be isolated from any of the feather vanes examined. For the most part, post mortem lesions do not reflect the organ pattern found to be most permissive for virus replication as judged by the success of virus isolation and virus titres. A closer quantitative correlation is indicated for the lungs, spleen and liver, only. Corresponding findings as to frequency of gross pathological lesions and virus quantification appear to be restricted to the liver. In accordance with clinical observations and experimental findings, tissue virus content indicates that horizontal spread of herpesviruses is mediated by cloacal contents or secretions from the respiratory system.

Outbreak of reproductive disorders and mycobacteriosis in swine associated with a single strain of Mycobacterium avium subspecies hominissuis

In a breeding and fattening pig farm an increasing number of cases of abortion and generalized mycobacteriosis at slaughter occurred. Pathological findings compatible with mycobacteriosis, acid-fast organisms in tissues, and isolation of mycobacteria from tissue samples including fetuses, lungs and reproductive organs from sows, genital swabs, mesenteric lymph nodes, and from a sperm sample revealed the cause of the disease. Bacterial cultures were identified as Mycobacterium avium subsp. hominissuis using IS901-/IS1245-specific PCR. Genotyping of selected isolates from animals as well as from their environment by MIRU-VNTR analysis showed that the herd was infected with one single outbreak strain. The same genotype was also isolated from pigs of two other farms which showed comparable symptoms and were in direct contact with the index farm as well as from their environment. Immunological host responses detected by tuberculin skin test and ELISA gave positive results at herd level only. Despite the detection of other potential pathogens mycobacteria were regarded as the causative agent of the reproductive disorders. To our knowledge this is the first report of an epidemic mycobacterial infection in a pig holding associated with reproductive disorders, which could be attributed to one single virulent strain, and the first report of detection of M. avium subsp. hominissuis in pig sperm.

Review of the literature and investigations on the prevalence and consequences of yeasts in reptiles

Ninety-one reptiles were examined for the presence of yeasts by standard protocols and pathohistological methods. Yeasts were isolated from 42 of the animals. Representatives of herbivorous families (Testudinidae and Iguanidae) carried yeasts more often than animals belonging to carnivorous taxa (Boidae and Emydidae). Yeasts were most often isolated from the gastrointestinal tract, and in 24-6 per cent of cases they could be cultured from the oral cavity and/or cloaca of living animals. Postmortem examination revealed that the intestines of 80-6 per cent of the animals carried yeasts. In all, 56 isolates, belonging to the genera Candida (32), Trichosporon (11), Torulopsis (9) and Rhodotorula (3), and one perfect yeast were obtained. The species included taxa potentially pathogenic to man. However, no sufficiently reliable criteria could be established to prove that positive culture results were associated with disease. In the reptiles examined postmortem, three cases of dermatomycosis were detected histologically. No case of organ mycosis was identified.

[A herpesvirus-caused enzootic--Pacheco's parrot disease--in a psittacine collection]

After the official confirmation of psittacosis in a collection of psittacine birds a total of 40 of them died during treatment with tetracycline. 36 of them underwent post mortem examination. From 33 birds the causative herpesvirus of Pacheco's parrot disease (PPD) was isolated and/or a non-purulent hepatitis diagnosed, the latter a characteristic for PPD. The cause of the outbreak was assumed to be a latent herpesvirus infection of individual birds which was activated by various stress factors during the psittacosis treatment. The macroscopic and histologic lesions, the results of virological investigations and the in vitro effect of acyclovir on the multiplication of the isolated herpes virus are described.

European brown hare syndrome virus: relationship to rabbit hemorrhagic disease virus and other caliciviruses

Monoclonal antibodies directed against the capsid protein of rabbit hemorrhagic disease virus (RHDV) were used to identify field cases of European brown hare syndrome (EBHS) and to distinguish between RHDV and the virus responsible for EBHS. Western blot (immunoblot) analysis of liver extract of an EBHS virus (EBHSV)-infected hare revealed a single major capsid protein species of approximately 60 kDa that shared epitopes with the capsid protein of RHDV. RNA isolated from the liver of an EBHSV-infected hare contained two viral RNA species of 7.5 and 2.2 kb that comigrated with the genomic and subgenomic RNAs of RHDV and were recognized by labeled RHDV cDNA in Northern (RNA) hybridizations. The nucleotide sequence of the 3' 2.8 kb of the EBHSV genome was determined from four overlapping cDNA clones. Sequence analysis revealed an open reading frame that contains part of the putative RNA polymerase gene and the complete capsid protein gene. This particular genome organization is shared by RHDV but not by other known caliciviruses. The deduced amino acid sequence of the capsid protein of EBHSV was compared with the capsid protein sequences of RDDV and other caliciviruses. The amino acid sequence comparisons revealed that EBHSV is closely related to RHDV and distantly related to other caliciviruses. On the basis of their genome organization, it is suggested that caliciviruses be divided into three groups.

Polychlorinated biphenyl congeners in foxes in Germany from 1983 to 1991

Red foxes served as a biological indicator for the temporal development of environmental contamination with polychlorinated biphenyls (PCB). The concentration of PCB congeners nos. 28, 49, 52, 101, 138, 153, and 180 were analyzed in the body fat of 80 foxes (Canis vulpes) from Germany. The samples were from animals that had been submitted for examination in 1983, 1987, and 1991. Throughout this time period, a reduction was seen in the concentration of the highly chlorinated biphenyls 138, 153, and 180, whereas the concentration of the low-chlorinated congeners PCB nos. 28, 49, and 52 increased. No change in contamination with congener 101 was observed. These results show a trend toward reduction of environmental contamination with highly-chlorinated biphenyls since 1983, while contamination with low-chlorinated congeners is apparently increasing. An interesting observation is the disproportionately higher amount of 2,2',3,4,4',5,5'-hepatachlorobiphenyl (PCB 180) over that of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) in body-fat samples from all foxes analyzed. This phenomenon was also observed in 10 dogs examined as controls. Based on evidence from other authors of experimental toxicological studies on beagles, it appears that the fox possesses a similar cytochrome P-450 isoenzyme that can degrade 2,4,5-trichloro-substituted aromatic compounds. As a consequence, in canines, PCB 180 which is additionally meta-chloro substituted is accumulated to a greater degree than is PCB 153.

Immunocytochemical demonstration of Coxiella burnetii antigen in the fetal placenta of naturally infected sheep and cattle

Coxiella burnetii antigen was demonstrated immunocytochemically in the placental tissues of aborted fetuses from four cows and two ewes and from one full-term calf. Antigen was observed in cytoplasmic vacuoles of trophoblasts, especially along the base of the chorionic villi. Positive trophoblasts were of normal size or exhibited striking cytoplasmic enlargement. Antigen was also demonstrated in neutrophils, degenerated cells and extracellularly in the intervillous spaces. The chorioallantoic connective tissue, allantoic surface and fetal tissues were devoid of C. burnetii antigen. Ovine placentas showed strong coxiella-specific staining and histological lesions characterized by moderate to severe, multifocal, necrotizing and purulent inflammation. In bovine placentas, the number of immunopositive cells varied from few to moderate and changes were mild or absent. Placental vasculitis consisting of infiltrating mononuclear cells, neutrophils or eosinophils was observed in both of the ovine and two of the bovine fetuses. In addition, a few intravascular thrombi were observed in one ovine and one bovine placenta. Thus the ovine coxiellosis cases were associated with an abundant accumulation of C. burnetii antigen and with severe necrotizing purulent placentitis, whereas in bovine coxiellosis the lesions were mild or absent and the number of organisms demonstrated immunocytochemically was much smaller. These results suggest a relation between species, lesion severity and weight of infection.

Incidence, epizootiology and control of viral haemorrhagic disease of rabbits and the European brown hare syndrome in Germany

Viral haemorrhagic disease (VHD) among domestic and wild rabbits and European brown hares have been observed in most of the Federal states of Germany. Acute outbreaks of viral haemorrhagic disease are most prevalent in small, fancy domestic rabbitries, with mortality varying between 5 and 90%, while mostly sporadic losses due to VHD are seen among wild rabbits. In hares, accumulated losses from the European brown hare syndrome (EBHS) can occasionally be observed in areas where fresh green feed, such as young O.O-rape plants, is available. VHD of rabbits and EBHS are caused by calicivirus strains. The natural virus reservoirs are wild rabbit and hare populations. Mutual infection of rabbits and hares seems to be possible. Transmission and spread of infectious virus occurs by direct contact of animals, or indirectly by contaminated excrement, green feed or living vectors. Calicivirus infections are widespread in several states, with accumulation of losses among domestic and wild rabbits by VHD, or in hares by EBHS, within certain areas. Disease hygiene, together with vaccination, are the officially preferred control measures in domestic rabbitries.

[Erysipelas in the roe deer--a case report]

An infection of a young male roe deer caused by Erysipelothrix rhusiopathiae with a pronounced thrombotic endocarditis in the left valves and focal necrosis in the septum of the heart leading to bacterial sepsis is described. Findings of this kind are extremely rare in roe deer. However, they document the wide host range, which is also illustrated by the numerous publications on such infections in other species.

[The etiology of liver dystrophy in the field hare (Lepus europaeus pallas)]

The liver dystrophy of the European Brown Hare is widely distributed in Europe and predominantly called European Brown Hare Syndrome (EBHS) or Hemorrhagic Septicemia Syndrome. The disease could be reproduced by injection of sterile filtered organ material of two field cases in two hares held in captivity. The clinical symptoms and the pathologic alterations are described.