Post streptococcal acute glomerulonephritis secondary to sporadic <Emphasis Type="Italic">Streptococcus equi</Emphasis> infection

Streptococcus equi subspecies zooepidemicus infection is rare in humans, but a well-known cause of pyogenic disease in cows and horses. S. zooepidemicus uncommonly causes post-strep glomerulonephritis (PSGN) in humans via epidemic outbreaks. We present a sporadic case of post S. zooepidemicus glomerulonephritis in a child most probably contracted from a horse. The 14-year-old girl presented with the typical signs of PSGN, with S. equi zooepidemicus isolated from a blood culture, together with a low C3 and raised anti-DNAse B. This is the first known report of a sporadic case of PSGN in a child caused by this organism.     

Outbreak Investigation of NADC30‐Like PRRSV in South‐East China

Epidemiological outbreak investigations were conducted on NADC30‐like porcine reproductive and respiratory syndrome virus (PRRSV) to investigate the prevalence of the disease in south‐east China in 2015. Two more provinces were found to have NADC30‐like PRRSV circulating besides previously reported six provinces. Phylogenetic analysis showed that these virus isolates were clustered in an independent branch and shared high nucleotide similarity to NADC30, a type 2 PRRSV that has been isolated in Unite States in 2008. One NADC30‐like PRRSV strain from Henan province was successfully isolated on porcine alveolar macrophages and was tested on 6‐week‐old specific pathogen‐free pigs for pathogenic study. The virus‐inoculated pigs showed typical PRRSV clinical symptoms, but all pigs survived throughout the study with a period of 14 days. At necropsy, the lungs of infected pigs developed PRRSV‐specific interstitial pneumonia, and virus antigen was detected in lung samples. Therefore, our results indicated NADC30‐like PRRSV has widely spread in China and could cause clinical disease on pigs.     

Genetic characterization of a novel recombinant PRRSV2 from lineage 8, 1 and 3 in China with significant variation in replication efficiency and cytopathic effects

There are four major porcine reproductive and respiratory syndrome virus 2 (PRRSV2) lineages circulating in China based on classification system, including lineages 1 (NADC30‐like), 3 (QYYZ‐like), 5.1 (VR2332‐like) and 8 (JXA1‐like/CH‐1a‐Like), which leads to the potential recombination. In the present study, a novel variant of PRRSV2 strain named JS18‐3 was isolated from piglets suffering severe breathing difficulties in Jiangsu Province of China in 2018. Full‐length genome analysis indicated that JS18‐3 shared 86.5%, 87.9%, 84.2%, 82.2% and 86.4% nucleotide similarity with PRRSVs CH‐1a, JXA1, VR2332, QYYZ and NADC30, respectively. 4871–6635 of JS18‐3 shared the highest identity of 99.3% in nucleotide sequence with HP‐PRRSV representative strain JXA1 indicating ongoing evolution to HP‐PRRSV. JS18‐3 was classified into classical lineage 8 of PRRSV2 based on phylogenetic analysis of complete genome and ORF5. Genomic break points in structural (ORF3) and non‐structural (NSP2, NSP3) regions of genomes were detected in recombination analysis. JS18‐3 is a recombinant isolate from lineages 8, 1 and 3. Replication enhancement and severe cytopathic effects caused by JS18‐3 were observed in Marc‐145 cells and porcine alveolar macrophages (PAMs) as compared to JX07, a typical strain of lineage 8. Pathogenicity results indicated that piglets inoculated with JS18‐3 presented persistent fever, dyspnoea, serious microscopic lung lesions and lymph node congestion. The study suggests that lineage 8 of PRRSV2 is involved in continuing evolution by genetic recombination and mutation leading to outbreaks in vaccinated pigs in China.     

Pathogenicity and Distribution of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus in Pigs

The pathogenesis of highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) strain (HuN4) is poorly understood. Therefore, highly pathogenic PRRSV strain (HuN4) and its derivative strain (HuN4‐F112) (obtained by propagation in MARC145 cells for 112 passages) were inoculated into a total of 48 PRRSV‐sero‐negative pigs (age: 4–5 weeks) by the intranasal route. Virological, pathological and in situ hybridization analyses were performed. The results exhibited that pigs infected with HuN4 showed a loss of appetite, decrease in body weight, raised body temperature and respiratory symptoms, along with interstitial pneumonia lesions. In the HuN4 group, multifocal interstitial pneumonia with macrophage infiltration was found in the lung. The lesions in the lymph node were characterized by collapsed follicles, depletion of germinal centres and reduction in lymphocytes. Perivascular cuffing and glial nodules were observed in the brains of some pigs. By comparison, the HuN4‐F112 group had milder lesions. PRRSV was detected in macrophages, alveolar epithelial cells and vascular endothelial cells in the tonsil and lymph nodes. The PRRSV amounts in the pigs infected with HuN4 were 10⁵–10⁹ copies/ml in the blood and 10¹⁰–10¹¹ copies/g in the lung tissues, whereas the virus amounts with HuN4‐F112 were 10^2.15–10^3.13 copies/ml in the blood and 10^3.0–10^3.6 copies/g in the lung. Our results demonstrate that the PRRS HuN4 virus infects alveolar epithelial cells, macrophages and vascular endothelial cells causing diffuse alveolar damage and lymph node necrosis. Its higher pathogenicity compared with HuN4‐F112 virus may be explained in part by higher replication rate in the previously mentioned organs.     

Detection of a novel sapelovirus in central nervous tissue of pigs with polioencephalomyelitis in the USA

An approximately 3,000 finishing swine operation in the United States experienced an outbreak of an atypical neurologic disease in 11‐weeks‐old pigs with an overall morbidity of 20% and case fatality rate of 30%. The clinical onset and progression of signs in affected pigs varied but included inappetence, compromised ambulation, ataxia, incoordination, mental dullness, paresis, paralysis and decreased response to environmental stimuli. Tissues from affected pigs were submitted for diagnostic investigation. Histopathologic examination of the cerebrum, cerebellum and spinal cord revealed severe lymphoplasmacytic and necrotizing polioencephalomyelitis with multifocal areas of gliosis and neuron satellitosis, suggestive of a neurotropic viral infection. Bacterial pathogens were not isolated by culture of neurologic tissue from affected pigs. Samples tested by polymerase chain reaction (PCR) were negative for pseudorabies virus and atypical porcine pestivirus. Immunohistochemistry for porcine reproductive and respiratory syndrome virus, porcine circovirus and Listeria was negative. Porcine sapelovirus (PSV) was identified in spinal cord by a nested PCR used to detect porcine enterovirus, porcine teschovirus and PSV. Next‐generation sequencing of brainstem and spinal cord samples identified PSV and the absence of other or novel pathogens. In addition, Sapelovirus A mRNA was detected in neurons and nerve roots of the spinal cord by in situ hybridization. The PSV is genetically novel with an overall 94% amino acid identity and 86% nucleotide identity to a recently reported sapelovirus from Korea. This is the first case report in the United States associating sapelovirus with severe polioencephalomyelitis in pigs.     

Pathology and Virus Distribution in the Lung and Lymphoid Tissues of Pigs Experimentally Inoculated with Three Distinct Type 1 PRRS Virus Isolates of Varying Pathogenicity

Porcine reproductive and respiratory syndrome (PRRS) continues to be the most economically important disease of swine worldwide. The appearance of highly pathogenic PRRS virus (PRRSV) strains in Europe and Asia has raised concerns about this disease and initiated increased efforts to understand the pathogenesis. In this study, we have compared the pathology and the virus distribution in tissues of pigs experimentally inoculated with three different genotype 1 PRRSV isolates. Sixty 5‐week‐old pigs were inoculated intranasally with a) the Lelystad virus (LV), b) a field strain from the UK causing respiratory clinical signs (UK) or c) a highly pathogenic strain from Belarus (BE). Sixteen animals were mock‐infected and used as controls. The animals were euthanized at 3, 7 and 35 days post‐infection (dpi), and lung and lymphoid tissues collected for histopathological examination and PRRSV detection by immunohistochemistry (IHC). Histopathological lesions consisted of interstitial pneumonia with mononuclear cell infiltrates in the lungs, lymphoid depletion, apoptosis and follicular hyperplasia in the spleen, lymph nodes and tonsil and lymphoid depletion in the thymus. Porcine reproductive and respiratory syndrome virus was detected mainly in monocytes–macrophages. BE‐infected animals showed the highest pathological scores and the highest presence of virus at 3 and 7 dpi, followed by the UK field strain and then LV. Moderate lesions were observed at 35 dpi with lesser detection of PRRSV by IHC in each infected group. The highly pathogenic BE strain induced more severe pathology in both lungs and lymphoid organs of pigs compared with the classic field isolate and the prototype LV. The increased severity of pathology was in correlation with the presence of a higher number of PRRSV‐infected cells in the tissues.     

Porcine reproductive and respiratory syndrome virus NADC30‐like strain accelerates Streptococcus suis serotype 2 infection in vivo and in vitro

Porcine reproductive and respiratory syndrome (PRRS), an economically significant pandemic disease, commonly results in increased impact of bacterial infections, including those by Streptococcus suis (S. suis). In recent years, PRRS virus (PRRSV) NADC30‐like strain has emerged in different regions of China, and coinfected with S. suis and PRRSV has also gradually increased in clinical performance. However, the mechanisms involved in host innate responses towards S. suis and their implications of coinfection with NADC30‐like strain remain unknown. Therefore, the pathogenicity of NADC30‐like strain and S. suis serotype 2 (SS2) coinfection in vivo and in vitro was investigated in this study. The results showed that NADC30‐like increased the invasion and proliferation of SS2 in blood and tissues, resulting in more severe pneumonia, myocarditis, and peritonitisas well as higher mortality rate in pigs. In vitro, NADC30‐like strain increased the invasion and survival of SS2 in porcine alveolar macrophages (PAM) cells, causing more drastic expression of inflammatory cytokines and activation of NF‐ĸB signalling. These results pave the way for understanding the interaction of S. suis with the swine immune system and their modulation in a viral coinfection.     

Novel porcine model of implant‐associated osteomyelitis: A comprehensive analysis of local,regional, and systemic response

Pigs are favorable experimental animals for infectious diseases in humans. However, implant‐associated osteomyelitis (IAO) models in pigs have only been evaluated using high‐inoculum infection (>10⁸ CFU) models in 1975 and 1993. Therefore, the aim of this paper was to present a new low inoculum porcine model of human IAO based on 42 experimental pigs. The model was created by drilling an implant cavity in the tibial bone followed by insertion of a small steel implant and simultaneous inoculation of Staphylococcus aureus bacteria (n = 32) or saline (n = 10). The infected pigs were either inoculated with 10⁴ CFU (n = 26) or 10² and 10³ CFU (n = 6). All animals were euthanized 5 days after insertion of implants. Pigs receiving the high‐inoculum infections showed a significantly higher volume of bone lesion, number of neutrophils around the implant, concentrations of acute phase proteins in serum, and enlargement of regional lymph nodes. A positive correlation was present between a high number of surrounding neutrophils and high values of all other parameters. Furthermore, a threshold of 40 neutrophils per 10 high power fields for the histopathological diagnosis of high grade IAO was defined. In conclusion: This paper describes a novel low‐inoculum S . aureus porcine model of IAO which was demonstrated to be reliable, reproducible and discriminative to human IAO, and represents a requested and valuable tool in orthopedic research. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2211–2221, 2017.

     

Factors associated with the prevalence of antibodies against Theileria equi in equids of Western Pará, Brazil

The State of Pará has one of the largest herds of equids (horse, donkey and mule) in Brazil, most of these animals are found on cattle farms. Equine theileriosis is a tick‐borne disease caused by the parasite Theileria equi and is characterized by fever, anaemia, icterus, intravascular haemolysis, haemoglobinuria, spleen and hepatomegaly, and even death. The present study aimed to determine the prevalence of antibodies against T. equi in equids in the western region of the State of Pará, Brazil, and to identify potential risk factors associated with parasite infection. A cross‐sectional study was conducted with cluster sampling of farm horses from 18 municipalities. In the cities visited, samples from sport and carthorses were also included. Serum was obtained to detect T. equi‐specific antibodies using an indirect enzyme‐linked immunosorbent assay (iELISA) based on a crude parasite antigen. In order to identify possible risk factors of the infection which are associated with the prevalence of antibodies, a chi‐squared test was carried out. Of 1,117 equids, 373 tested positive for T. equi antibodies with an overall prevalence of 33.4% (31.3%–37.0% for the 95% confidence interval). Sex, animal species and breed were found not to be associated with the presence of T. equi antibodies, whereas age, the presence of dogs or ticks were associated with seropositivity (p < 0.05). Horses with ticks were 2.4 more likely seropositive than horses without ticks. The presence of dogs in the equid habitat and the presence of ticks resulted in a higher T. equi seropositive rate probably because dogs are hosts for vector ticks of T. equi. Our study represents the first report of T. equi antibodies in equids of western Pará revealing a widespread distribution of seropositive animals.     

Similar frequency of Porcine circovirus 3 (PCV‐3) detection in serum samples of pigs affected by digestive or respiratory disorders and age‐matched clinically healthy pigs

Porcine circovirus 3 (PCV‐3) has been identified in pigs affected by different disease conditions, although its pathogenicity remains unclear. The objective of the present study was to assess the frequency of PCV‐3 infection in serum samples from animals suffering from post‐weaning respiratory or digestive disorders as well as in healthy animals. A total of 315 swine serum samples were analysed for PCV‐3 DNA detection by conventional PCR; positive samples were further assayed with a quantitative PCR and partially sequenced. Sera were obtained from 4 week‐ to 4 month‐old pigs clinically diagnosed with respiratory (n = 129) or digestive (n = 126) disorders. Serum samples of age‐matched healthy animals (n = 60) served as negative control. Pigs with clinical respiratory signs had a wide variety of pulmonary lesions including suppurative bronchopneumonia, interstitial pneumonia, fibrinous‐necrotizing pneumonia and/or pleuritis. Animals with enteric signs displayed histopathological findings like villus atrophy and fusion, catarrhal enteritis and/or catarrhal colitis. Overall, PCV‐3 DNA was detected in 19 out of 315 analysed samples (6.0%). Among the diseased animals, PCV‐3 was found in 6.2% (8 out of 129) and 5.6% (7 out of 126) of pigs with respiratory and digestive disorders, respectively. The frequency of PCV‐3 PCR positive samples among healthy pigs was 6.7% (4 out of 60). No apparent association was observed between PCR positive cases and any type of histopathological lesion. The phylogenetic analysis of the partial genome sequences obtained showed high identity among viruses from the three groups of animals studied. In conclusion, PCV‐3 was present in the serum of diseased and healthy pigs to similar percentages, suggesting that this virus does not seem to be causally associated with respiratory or enteric disorders.     

Experimental Transmission of African Swine Fever (ASF) Low Virulent Isolate NH/P68 by Surviving Pigs

African swine fever (ASF) has persisted in Eastern Europe since 2007, and two endemic zones have been identified in the central and southern parts of the Russian Federation. Moderate‐ to low‐virulent ASF virus isolates are known to circulate in endemic ASF‐affected regions. To improve our knowledge of virus transmission in animals recovered from ASF virus infection, an experimental in vivo study was carried out. Four domestic pigs were inoculated with the NH/P68 ASF virus, previously characterized to develop a chronic form of ASF. Two additional in‐contact pigs were introduced at 72 days post‐inoculation (dpi) in the same box for virus exposure. The inoculated pigs developed a mild form of the disease, and the virus was isolated from tissues in the inoculated pigs up to 99 dpi (pigs were euthanized at 36, 65, 99 and 134 dpi). In‐contact pigs showed mild or no clinical signs, but did become seropositive, and a transient viraemia was detected at 28 days post‐exposure (dpe), thereby confirming late virus transmission from the inoculated pigs. Virus transmission to in‐contact pigs occurred at four weeks post‐exposure, over three months after the primary infection. These results highlight the potential role of survivor pigs in disease maintenance and dissemination in areas where moderate‐ to low‐virulent viruses may be circulating undetected. This study will help design better and more effective control programmes to fight against this disease.     

A novel NADC30‐like porcine reproductive and respiratory syndrome virus (PRRSV) plays a limited role in the pathogenicity of porcine circoviruses (PCV2 and PCV3) and PRRSV co‐infection

Co‐infection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circoviruses (PCVs) is commonly observed under field conditions and elicits more severe diseases than any singular infection. In this study, the co‐infection of PRRSV, PCV2 and PCV3 was analyzed in tissue samples collected from 150 pigs from April 2016 to April 2018. PRRSV, PCV2 and PCV3 was detected in 55 (36.67%), 43 (28.67%) and 3 (2%) of 150 pigs respectively. Remarkably, one lung sample (SD17‐36) collected from a diseased pig was co‐infected with PRRSV, PCV2 and PCV3. The complete genomes of SD17‐36 viruses of PRRSV, PCV2 and PCV3 were determined, which belong to the subgroups of NADC30‐like PRRSV, PCV2d and PCV3a respectively. Sequence comparison showed that PRRSV SD17‐36 isolate contains a N33 deletion in GP5. Animal challenge study showed that the novel NADC30‐like PRRSV SD17‐36 isolate is low pathogenic. Our results indicate that the co‐infection of PRRSV and PCVs might cause diseases even when PRRSV plays a limited role in the pathogenicity of the co‐infection.     

Pathology of Trichuris suis Infection in Pigs Fed an Inulin‐ and a Non‐inulin‐containing Diet

Pathology of the colon in pigs infected with Trichuris suis and fed an inulin and a non‐inulin containing diet was studied to investigate the inflammatory response induced and the influence of inulin on this. Twenty‐nine pigs were allocated into four groups (N‐7, I‐7, N‐9 and N/I‐9). Groups N‐7, N‐9 and N/I‐9 were given a diet with non‐fermentable carbohydrates, and group I‐7 was fed a diet including fermentable carbohydrates (inulin). After 2 weeks, all pigs were inoculated with 2000 T. suis eggs. Seven weeks post‐infection (p.i.), groups N‐7 and I‐7 were killed and group N/I‐9 changed to inulin diet to study the influence of inulin on already established T. suis. Nine weeks p.i., groups N‐9 and N/I‐9 were killed. Trichuris suis were collected from the colon for enumeration. Tissues from the colon of each pig were taken for histological and immunohistochemical quantitative and semi‐quantitative evaluations of heterophils, eosinophils, mast cells, IgA⁺, IgG⁺, IgM⁺ and CD3⁺ cells. The findings were compared with tissues from seven uninfected pigs of the same age. Pigs fed inulin had significantly fewer worms compared with pigs on the non‐fermentable carbohydrate diet. The number of inflammatory cells in the colonic mucosa was increased in all T. suis‐infected pigs compared with uninfected controls. The numbers of eosinophils, mast cells, IgA⁺, IgG⁺ and CD3⁺ cells were significantly lower in pigs fed inulin than pigs fed non‐fermentable carbohydrate. Whether this is a direct effect of inulin or a secondary effect due to the lower parasitic burden in inulin fed pigs is not known.     

Glomérulonéphrite aiguë post-infectieuse à Streptococcus equi subsp. zooepidemicus : premier cas décrit en France

Post-infectious glomerulonephritis has become exceptional in France because streptococcus infections are well-treated. When they appear, clinical and biological symptoms are mostly typical and associate acute nephritic syndrome, acute renal failure, proteinuria, hematuria and low complement. We are reporting the first French case of acute post-infectious glomerulonephritis related to Streptococcus equi subsp. zooepidemicus, which is commonly found in horses and rarely in human pathology, and of which contamination is by direct contact with sick horses or by ingestion of non-pasteurized milk.     

A natural recombinant PRRSV between HP‐PRRSV JXA1‐like and NADC30‐like strains

Porcine reproductive and respiratory syndrome virus (PRRSV ) is a major economically significant pathogen that has adversely affected China's swine industry. Currently, a novel type 2 PRRSV , called the NADC 30‐like strain, is epidemic in numerous provinces of China, and commercial vaccines provide limited protection for infected animals. The extensive recombination phenomenon among NADC 30‐like PRRSV s is identified as a unique molecular characteristic of the virus. However, our understanding of how recombination influences NADC 30‐like PRRSV s is largely inadequate. In this study, we analysed the genetic characteristics of a recombinant NADC 30‐like PRRSV (SC ‐d) and examined its pathogenicity compared with a non‐recombinant NADC 30‐like PRRSV (SD ‐A19) and a highly pathogenic PRRSV (HuN4). SC ‐d has three discontinuous deletions in nsp2, consistent with NADC 30 isolated from the United States in 2008. Furthermore, we identified four recombination breakpoints in the SC ‐d genome, which separated the SC ‐d genome into four regions (regions A, B, C and D). Regions A and C are closely related to the JXA 1‐like strain, one of the earliest Chinese HP ‐PRRSV strains, and regions B and D are closely related to the NADC 30 strain. Moreover, SC ‐d inoculated piglets exhibited a persistent fever, moderate weight loss, mild thymus atrophy and obvious microscopic lung lesions. In summary, the recombinant NADC 30‐like PRRSV SC ‐d strain displayed a higher pathogenicity than the non‐recombinant NADC 30‐like PRRSV SD ‐A19 strain; however, the pathogenicity of the NADC 30‐like PRRSV SC ‐d was lower compared with the HP ‐PRRSV HuN4 strain in piglets. Our findings demonstrate that recombination is responsible for the enormous genetic diversity and pathogenicity variance of the NADC 30‐like PRRSV in China. This study provides a theoretical basis for developing a more reasonable PRRSV control and prevention strategy.     

Prolonged Detection of PCV2 and Anti‐PCV2 Antibody in Oral Fluids Following Experimental Inoculation

The onset, level and duration of PCV2 and anti‐PCV2 antibody in oral fluid were evaluated using samples collected from experimentally inoculated pigs for 98 days post‐inoculation (DPI). Pigs (n = 24) were obtained at 3 weeks of age and randomly allocated to 4 treatment pens of 6 pigs each: (i) negative control group; (ii) inoculated with PCV2a (strain ISU 40895) on DPI 0; (iii) inoculated with PCV2a (strain ISU‐40895) on DPI 0 and re‐challenged at DPIs 35 and 70; (iv) inoculated with PCV2a (ISU‐40895), PCV2b (PVG4072) and PCV2a (ISU‐4838) on DPIs 0, 35 and 70, respectively. Serum was collected from each animal, and one oral fluid sample was collected from each pen (group) every other day from DPI 2 through DPI 14 and weekly through 98 DPI. Oral fluid samples were assayed for the presence of PCV2 by quantitative polymerase chain reaction (qPCR) and anti‐PCV2 IgG, IgA and IgM antibody isotypes by enzyme‐linked immunosorbant assay (ELISA). Serum was assayed for anti‐PCV2 IgG by ELISA. Anti‐PCV2 antibodies (IgG, IgM and IgA) were detected in oral fluid from experimentally inoculated pigs from DPI 14 with IgG and IgA clearly present at 98 DPI. PCV2 was detected in oral fluid samples from all pens of inoculated pigs at 2 DPI. Thereafter, PCV2 was detected in oral fluid throughout 98 DPI. Overall, the data indicated that PCV2 infection in swine is prolonged, persists in the face of an active antibody response and can be efficiently monitored using oral fluid specimens.