Rodents are the most abundant and diversified order of living mammals in the world. Already since the Middle Ages we know that they can contribute to human disease, as black rats were associated with distribution of plague. However, also in modern times rodents form a threat for public health. In this review article a large number of pathogens that are directly or indirectly transmitted by rodents are described. Moreover, a simplified rodent disease model is discussed.

Rodent-borne diseases and their risks for public health

Three-week-old cesarean-derived colostrum-deprived (CD/CD) pigs were inoculated with porcine circovirus type 2 (PCV2, n 19), porcine reproductive and respiratory syndrome virus (PRRSV, n 13), concurrent PCV2 and PRRSV (PCV2/PRRSV, n 17), or a sham inoculum (n 12) to compare the indepen- dent and combined effects of these agents. Necropsies were performed at 7, 10, 14, 21, 35, and 49 days postinoculation (dpi) or when pigs became moribund. By 10 dpi, PCV2/PRRSV-inoculated pigs had severe dyspnea, lethargy, and occasional icterus; after 10 dpi, mortality in this group was 10/11 (91%), and all PCV2/ PRRSV-inoculated pigs were dead by 20 dpi. PCV2-inoculated pigs developed lethargy and sporadic icterus, and 8/19 (42%) developed exudative epidermitis; mortality was 5/19 (26%). PRRSV-inoculated pigs developed dyspnea and mild lethargy that resolved by 28 dpi. Microscopic lesions consistent with postweaning multisys- temic wasting syndrome (PMWS) were present in both PCV2- and PCV2/PRRSV-inoculated pigs and included lymphoid depletion, necrotizing hepatitis, mild necrotizing bronchiolitis, and infiltrates of macrophages that occasionally contained basophilic intracytoplasmic inclusion bodies in lymphoid and other tissues. PCV2/ PRRSV-inoculated pigs also had severe proliferative interstitial pneumonia and more consistent hepatic lesions. The most severe lesions contained the greatest number of PCV2 antigen-containing cells. PRRSV-inoculated pigs had moderate proliferative interstitial pneumonia but did not develop bronchiolar or hepatic lesions or lymphoid depletion. All groups remained seronegative to porcine parvovirus. The results indicate that 1) PCV2 coinfection increases the severity of PRRSV-induced interstitial pneumonia in CD/CD pigs and 2) PCV2 but not PRRSV induces the lymphoid depletion, granulomatous inflammation, and necrotizing hepatitis character- istic of PMWS.

https://journals.sagepub.com/doi/pdf/10.1354/vp.38-5-528

Experimental Reproduction of Severe Disease in CD/CD Pigs Concurrently Infected with Type 2 Porcine Circovirus and Porcine Reproductive and Respiratory Syndrome Virus:

Infection of animals with a molecular viral clone is critical to study the genetic determinants of viral replication and virulence in the host. Type 2 porcine circovirus (PCV2) has been incriminated as the cause of postweaning multisystemic wasting syndrome (PMWS), an emerging disease in pigs. We report here for the first time the construction and use of an infectious molecular DNA clone of PCV2 to characterize the disease and pathologic lesions associated with PCV2 infection by direct in vivo transfection of pigs with the molecular clone. The PCV2 molecular clone was generated by ligating two copies of the complete PCV2 genome in tandem into the pBluescript SK (pSK) vector and was shown to be infectious in vitro when transfected into PK-15 cells. Forty specific-pathogen-free pigs at 4 weeks of age were randomly assigned to four groups of 10 each. Group 1 pigs served as uninoculated controls. Pigs in group 2 were each inoculated intranasally with about 1.9 × 105 50% tissue culture infective doses of a homogeneous PCV2 live virus stock derived from the molecular clone. Pigs in group 3 were each injected intrahepatically with 200 μg of the cloned PCV2 plasmid DNA, and pigs in group 4 were each injected into the superficial iliac lymph nodes with 200 μg of the cloned PCV2 plasmid DNA. Animals injected with the cloned PCV2 plasmid DNA developed infection resembling that induced by intranasal inoculation with PCV2 live virus stock. Seroconversion to PCV2-specific antibody was detected in the majority of pigs from the three inoculated groups at 35 days postinoculation (DPI). Viremia, beginning at 14 DPI and lasting 2 to 4 weeks, was detected in the majority of the pigs from all three inoculated groups. There were no remarkable clinical signs of PMWS in control or any of the inoculated pigs. Gross lesions in pigs of the three inoculated groups were similar and were characterized by systemically enlarged, tan lymph nodes and lungs that failed to collapse. Histopathological lesions and PCV2-specific antigen were detected in numerous tissues and organs, including brain, lung, heart, kidney, tonsil, lymph nodes, spleen, ileum, and liver of infected pigs. This study more definitively characterizes the clinical course and pathologic lesions exclusively attributable to PCV2 infection. The data from this study indicate that the cloned PCV2 genomic DNA may replace infectious virus for future PCV2 pathogenesis and immunization studies. The data also suggest that PCV2, although essential for development of PMWS, may require other factors or agents to induce the full spectrum of clinical signs and lesions associated with advanced cases of PMWS.

Cloned genomic DNA of type 2 porcine circovirus is infectious when injected directly into the liver and lymph nodes of pigs: characterization of clinical disease, virus distribution, and pathologic lesions.

Porcine circovirus type 2 (PCV2) is associated with postweaning multisystemic wasting syndrome in pigs, whereas PCV1 is nonpathogenic. We previously demonstrated that a chimeric PCV1-2 virus (with the immunogenic capsid gene of PCV2 cloned into the backbone of PCV1) induces an antibody response to the PCV2 capsid protein and is attenuated in pigs. Here, we report that the attenuated chimeric PCV1-2 induces protective immunity to wild-type PCV2 challenge in pigs. A total of 48 specific-pathogen-free piglets were randomly and equally assigned to four groups of 12 pigs each. Pigs in group 1 were vaccinated by intramuscular injection with 200 μg of the chimeric PCV1-2 infectious DNA clone. Pigs in group 2 were vaccinated by intralymphoid injection with 200 μg of a chimeric PCV1-2 infectious DNA clone. Pigs in group 3 were vaccinated by intramuscular injection with 103.5 50% tissue culture infective doses (TCID50) of the chimeric PCV1-2 live virus. Pigs in group 4 were not vaccinated and served as controls. By 42 days postvaccination (DPV), the majority of pigs had seroconverted to PCV2 capsid antibody. At 42 DPV, all pigs were challenged intranasally and intramuscularly with 2 × 104.5 TCID50 of a wild-type pathogenic PCV2 virus. By 21 days postchallenge (DPC), 9 out of the 12 group 4 pigs were viremic for PCV2. Vaccinated animals in groups 1 to 3 had no detectable PCV2 viremia after challenge. At 21 DPC the lymph nodes in the nonvaccinated pigs were larger (P < 0.05) than those of vaccinated pigs. The PCV2 genomic copy loads in lymph nodes were reduced (P < 0.0001) in vaccinated pigs. Moderate amounts of PCV2 antigen were detected in most lymphoid tissues of nonvaccinated pigs but in only 1 of 36 vaccinated pigs. Mild-to-severe lymphoid depletion and histiocytic replacement were detected in lymphoid tissues in the majority of nonvaccinated group 4 pigs but in only a few vaccinated group 1 to 3 pigs. The data from this study indicated that when given intramuscularly in pigs, the attenuated chimeric PCV1-2 live virus, as well as the chimeric PCV1-2 infectious DNA clone, induces protective immunity against PCV2 infection and could potentially serve as an effective vaccine.

A Chimeric Porcine Circovirus (PCV) with the Immunogenic Capsid Gene of the Pathogenic PCV Type 2 (PCV2) Cloned into the Genomic Backbone of the Nonpathogenic PCV1 Induces Protective Immunity against PCV2 Infection in Pigs

Serum samples from 78 European wild boars (Sus scrofa) harvested during the 1999–2000 hunting season were tested for antibodies to Brucella spp., classical swine fever virus, Erysipelothrix rhusiopathiae, Haemophilus parasuis, Leptospira interrogans serovar pomona, Mycoplasma hyopneumoniae, pseudorabies virus (PRV), porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus, Salmonella serogroups B, C, and D, Streptococcus suis, and swine influenza virus (SIV) serotypes H1N1 and H3N2. Samples were collected from Sierra Morena and Montes de Toledo in southcentral Spain. Antibodies were detected to PRV (36%), L. interrogans serovar pomona (12%), PPV (10%), E. rhusiopathiae (5%), SIV serotype H1N1 (4%), Salmonella serogroup B (4%), and Salmonella serogroup C (3%). Our results suggest that more research is needed to describe the epidemiology of infectious diseases of Spanish wild boars.

/pdf/antibodies-to-selected-viral-and-bacterial-pathogens-in-4h6hvuum5x.pdf

Antibodies to selected viral and bacterial pathogens in European wild boars from southcentral Spain.

Differences in the pathogenesis of porcine parvovirus (PPV) were shown when pregnant gilts were infected by the oral and intramuscular (i.m.) routes.

Observations on the pathogenesis of porcine parvovirus infection

Basic variables of the haemagglutination inhibition (HI) test for porcine parvovirus antibody were investigated. Nonspecific serum inhibitors were satisfactorily removed without loss of specific antibody when undiluted serum was adsorbed with 25 percent kaolin in borate saline at pH 9.0. Natural haemagglutinins in test serums could be completely removed using 0.1 ml of packed erythrocytes to 0.6 ml of kaolin treated serums. Adsorption of prediluted serum resulted in a depression of specific antibody titres. Highest HI titres were obtained using guinea pig erythrocytes, following incubation of virus-serum mixtures for 18 hours at 4 degrees C, 3 hours at 25 degrees C or 2 hours at 37 degrees C. Micro- and macro-tests gave comparable HI titres.

A standardised haemagglutination inhibition test for porcine parvovirus antibody.

Pathogenesis of porcine parvovirus infection: Pathology and immunofluorescence in the foetus

The safety and immunogenicity of inactivated porcine parvovirus (PPV) vaccines were investigated. Both beta-propiolactone and formalin successfully inactivated virus without destroying immunogenicity, which was considerably enhanced by incorporation of a gel adjuvant in the vaccine. Using the formalised-gel vaccine, initial antibody responses were demonstrated in susceptible piglets and adult pigs at 7 days after vaccination. These antibody responses persist at significant levels for at least 6 months after vaccination. Antibody levels increased up to 16 fold when revaccination was carried out. Vaccination of gilts with low level (passive) immunity resulted in antibody responses comparable to those recorded in susceptible pigs. The vaccine was safe as determined by absence of residual virus in the vaccine, absence of viraemia and excretion in vaccinted stock, and absence of effect on litters of sows vaccinated at different gestational ages. Vaccine stored at 4 degrees C for 6 months was as immunogenic as fresh vaccine.

Serological responses in pigs vaccinated with inactivated porcine parvovirus.

A microplate test was developed for the determination of neutralizing antibody titers against porcine parvovirus. End points were read directly by using haemagglutination techniques. The test was proved to be highly sensitive and reproducible.

A microneutralization test for the assay of porcine parvovirus antibody.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

H. S. Joo

Author Tools

Chat about Author