Circoviridae
Torque teno virus
Circovirus
Wasting Syndrome
Chicken anemia virus
Porcine Postweaning Multisystemic Wasting Syndrome
Ultrastructure of porcine circovirus in persistently infected PK-15 cells. (1/285)
The ultrastructure of porcine circovirus was examined in persistently infected porcine kidney (PK)-15 cells. Virus-infected PK-15 cells had large numbers of intracytoplasmic inclusions, and a few cells had intranuclear inclusions. Intracytoplasmic inclusions were dispersed throughout the cytoplasm but were most numerous in the perinuclear cytoplasm. Inclusion were of various sizes, round to oval, and electron dense and were of two general types. Inclusions of the first type were small (0.1-0.5 microm diameter), not surrounded by trilaminar membranes, and granular with indistinct margins that blended with surrounding cytoplasm. Some contained 12+/-2-nm-diameter icosahedral virions in loose aggregates or rarely forming paracrystalline arrays. Small inclusions could be sites of viral assembly or maturation. Intracytoplasmic inclusions of the second type were larger (0.5-5.0 microm diameter) and more numerous and had abrupt margins surrounded by trilaminar membranes. They were more electron dense than small inclusions and were heterogeneous, containing various proportions of aggregated virions, electron-dense crystalline lamellae of 5 nm periodicity, and/or whorls of myelinoid membranes. Virions usually formed paracrystalline arrays and occasionally were loosely aggregated. Larger inclusions were typical of autophagolysosomes. Intranuclear inclusions were not membrane bound and were often associated with reticulated nucleoli or aggregates of heterochromatin. Some inclusions were irregularly shaped aggregates of indistinct, circular 10-12-nm-diameter viruslike particles. Others were 0.1-1.0 microm in diameter, round or ring shaped, dense, and finely granular, with sharply demarcated margins. (+info)Observations on pigeon circovirus infection in Ontario. (2/285)
Subclinical pigeon circovirus infection was diagnosed in 1-day-old to 6-week-old birds from a loft with no history of clinical disease. Pigeons from other lofts presented with various illnesses and were found at necropsy to be concurrently infected with pigeon circovirus. (+info)Electron microscopical observations of psittacine beak and feather disease in an Umbrella cockatoo (Cacatua alba). (3/285)
Psittacine beak and feather disease (PBFD) was diagnosed in an umbrella cockatoo (Cacatua alba) with severe feather dystrophy and loss. Electron microscopically, the intranuclear and intracytoplasmic inclusion bodies observed by light microscopy were composed of viral particles forming paracrystalline arrays, whorls, semicircles or concentric circles. Recovered viral particles from the skin and feather follicle tracts were icosahedral and 15 to 20 nm in diameter. (+info)Detection of porcine circovirus from lesions of a pig with wasting disease in Japan. (4/285)
A wasting disease characterized by progressive weight loss and dyspnea has been observed in weaning pigs on a farm in Yamagata Prefecture in 1998. Histopathologic findings in an affected pig were bronchointerstitial pneumonia and intracytoplasmic clusters of basophilic inclusions in macrophages of lymph nodes, which were similar to those in pigs with postweaning multisystemic wasting syndrome (PMWS) recently reported in North America and Europe. Porcine circovirus (PCV)-like particles were observed in bronchial lymph node of the pig by electron microscopy, and PCV antigens were detected in the lesions by immunohistochemical staining. PCV DNA was also detected in the lung and tonsil by PCR, and restriction fragment length polymorphism analysis of the PCR products with HinfI showed the same type of the PCV associated with PMWS (pmws PCV). Homology of nucleotide sequences between the PCR product and corresponding regions of published pmws PCV genomes was very high. These results indicated that virus detected in this study was pmws PCV. To our knowledge, this is the first report on the presence of pmws PCV in Japan. (+info)Multiplex PCR for detection and typing of porcine circoviruses. (5/285)
Sets of oligonucleotide primers were designed according to the sequences of the open reading frames (ORFs) ORF1 and ORF2 of the prototype nonpathogenic PK-15 strain of porcine circovirus (PCV) type 1 (PCV-1). By the PCR performed with the various primer sets, genomic DNA or RNA from other bacterial or viral pathogens of the respiratory tracts of pigs could not be amplified. A positive amplification reaction could be visualized with DNA extracted from a viral suspension containing as few as 10 viral particles per ml. No DNA fragment could be amplified from lysates of continuous porcine cell lines (PT, ST, and PFT cells) known to be negative for PCV. When tested with clinical samples from pigs, the results of the single PCR method showed nearly 93% (13 of 14 samples) correlation with histopathological and immunohistochemical findings. Interestingly, subclinical PCV infections could be detected by single PCR with clinical samples that have been submitted from animals with irrelevant cases of respiratory and/or enteric problems. On the basis of the nucleotide sequences of PCV strains (PCV-2) recently associated with outbreaks of postweaning multisystemic wasting syndrome (PWMS) in Quebec, Canada, pig farms, other primers were designed from the PCV-1 genome, and these primers failed to amplify genomic fragments specific to the ORF1 or ORF2 genes of clinical isolates associated with PWMS but amplified DNA from the PCV-1 strain. Two rapid multiplex PCR (mPCR) methods have been developed to distinguish between both genotypes of PCV. By those two mPCR methods, (i) species-specific primer pairs were used to amplify a DNA fragment of 488 bp specific for the ORF2 genes of both genotypes, whereas a 375-bp fragment was amplified from the ORF1 gene of the PCV-1 strain only, or (ii) species-specific primer pairs were used to amplify a DNA fragment of 646 bp specific for the ORF1 genes of both genotypes, whereas a 425-bp fragment was amplified from the ORF2 gene of the PCV-1 strain only. By both mPCR methods, a PCV-2 infection was demonstrated in tissues of 94.2% (33 of 35) of the sick pigs tested, in agreement with previous findings showing the close association of this new genotype of PCV with outbreaks of PMWS in Europe and North America. On the other hand, a PCV-1 infection was confirmed in only 5.7% (2 of 35) of the pigs, and confirmation of a mixed infection with PCV-2 was obtained by a single PCR with PCV-2-specific primers. (+info)PCR detection and characterization of type-2 porcine circovirus. (6/285)
A polymerase chain reaction (PCR) assay was developed for detecting porcine circovirus (PCV). The assay readily detected type-2 PCV (PCV-2) and type-1 PCV (PCV-1). The PCR primers were designed based on DNA sequences conserved in all reported PCV genomes. Type 1 PCV and type 2 PCV both produced 438 bp amplification products, which were easily identified and differentiated from one another by restriction fragment length polymorphism (RFLP) analysis. Porcine circovirus was detected in 55% (931/1693) of randomly tested pigs with various clinical signs and lesions, most of which were difficult to differentiate from those associated with porcine reproductive and respiratory syndrome (PRRS). The PCR products from all positive clinical samples were identified by RFLP to be only PCV-2; DNA tested by PCR was extracted directly from one or more of lung, mesenteric or mediastinal lymph nodes, and tonsil. Type 2 PCV was also detected in 6% (2/34) of DNA extracted directly from semen of randomly chosen healthy boars. Positive PCR reactions from 554 diseased pigs were characterized by RFLP and categorized into 5 different profiles (A-E), of which 82.8% were PCV-2A (456/554), 3.0% were PCV-2B (17/554), 9.9% were PCV-2C (55/554), 1.1% were PCV-2D (6/554), and 3.2% were PCV-2E (18/554). The complete genomic nucleotide sequences of PCV-2A, B, C, D, and E were determined and found to have at least 95% homology compared with one another and with all other PCV-2 found in the GenBank database. All PCV-2 had less than 76% homology with PCV-1. This PCR assay will hopefully be useful to veterinary diagnostic laboratories for routine testing and surveillance of infection with PCV-2. The RFLP profiling system might be useful for preliminary characterization and identification of PCV isolates and might also benefit studies on the molecular epidemiology of PCV. (+info)Porcine postweaning multisystemic wasting syndrome in Korean pig: detection of porcine circovirus 2 infection by immunohistochemistry and polymerase chain reaction. (7/285)
This report describes the first diagnosis of porcine circovirus (PCV) infection in weaned pigs with postweaning multisystemic wasting syndrome in Korea by immunohistochemistry and polymerase chain reaction. The most unique lesions were multifocal granulomatous inflammation affecting lymph nodes, liver, and spleen, characterized by infiltrates of epithelioid macrophages and multinucleated giant cells. Circoviral antigen was detected in formalin-fixed sections and was usually present in large, round, dendritic cells in the white pulp of spleen and remnants of follicles in lymph nodes. Lymphoid follicles in the tonsils also contained PCV antigen. A 530-bp DNA fragment of circovirus was successfully amplified from all tested lymph nodes, liver, and spleen. (+info)High prevalence of TT virus DNA in human saliva and semen. (8/285)
Using the PCR assay, we found a high prevalence of TT virus (TTV) DNA in saliva and semen from patients who were seropositive for TTV. This finding suggests that the presence of TTV in body fluids other than serum may affect the routes of viral transmission. (+info)Circoviridae is a family of small, non-enveloped viruses that infect a wide range of hosts, including birds, pigs, and some primates. The virions of Circoviridae are icosahedral in shape and have a diameter of approximately 20 nanometers. The genome of these viruses is circular, single-stranded DNA that is around 2 kilobases in length.
The family Circoviridae includes two genera: Circovirus and Gyrovirus. Circoviruses are known to infect birds and pigs, while gyroviruses primarily infect birds. The most well-known circovirus is the porcine circovirus (PCV), which can cause a variety of clinical signs in pigs, including respiratory disease, enteritis, and reproductive failure. Gyroviruses, on the other hand, have been associated with various diseases in birds, such as inclusion body hepatitis and lymphoproliferative disease.
It's worth noting that circoviruses have also been detected in humans, although their clinical significance is not yet fully understood. Some studies have suggested a possible link between human circovirus infection and certain diseases, such as cardiovascular disease and diabetes, but more research is needed to confirm these findings.
Circoviridae is a family of small, non-enveloped viruses that infect a wide range of hosts, including animals and birds. The infection caused by circoviruses in animals and birds can result in a variety of symptoms depending on the species infected and the particular circovirus involved.
In pigs, circovirus type 2 (PCV2) is the most well-known member of this family and is associated with a number of clinical conditions, collectively known as porcine circovirus diseases (PCVD). These conditions include postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS), and reproductive failure.
In birds, circoviruses can cause various symptoms such as runting and stunting, feather abnormalities, and immunosuppression, leading to secondary infections. The most well-known avian circovirus is the beak and feather disease virus (BFDV), which infects psittacine birds, including parrots, causing beak deformities, feather loss, and immune suppression.
However, it's important to note that circoviruses are also found in humans, but currently, there is no evidence that human circovirus infections cause disease.
In general, circoviridae infections can be diagnosed through various laboratory tests such as PCR, sequencing, and serology. Treatment typically involves supportive care and management of secondary infections, as there are no specific antiviral therapies available for circovirus infections. Prevention strategies include good biosecurity practices, vaccination, and avoidance of contact with infected animals or their feces.
Torque teno virus (TTV) is a single-stranded DNA virus that belongs to the family Anelloviridae. It was first identified in 1997 and has since been found to be present in the majority of human populations worldwide. The virus is classified into several genotypes and subtypes, with TTV being the prototype member of the genus Alphainellovirus.
TTV is a small virus, measuring only about 30-40 nanometers in diameter. It has a circular genome that ranges in size from 2.8 to 3.9 kilobases and encodes for several non-structural proteins involved in viral replication. The virus does not appear to cause any specific disease symptoms, but it has been associated with various clinical conditions such as liver disease, respiratory tract infections, and cancer.
TTV is primarily transmitted through the fecal-oral route, although other modes of transmission have also been suggested, including saliva, blood, and vertical transmission from mother to child during pregnancy or delivery. The virus has been detected in various body fluids, tissues, and organs, including blood, stool, respiratory secretions, and the liver.
The clinical significance of TTV infection remains unclear, as it is frequently found in both healthy individuals and those with various diseases. However, some studies have suggested that TTV viral load or genotype may be associated with certain clinical conditions, such as liver disease, transplant rejection, and cancer. Further research is needed to better understand the role of TTV in human health and disease.
Circoviruses are a type of small, non-enveloped viruses that belong to the family Circoviridae. They have a single-stranded, circular DNA genome and can infect a wide range of hosts, including birds, pigs, and some mammals. Circoviruses are associated with various diseases in animals, such as porcine circovirus-associated disease (PCVAD) in pigs and beak and feather disease in birds. However, there is currently no evidence to suggest that circoviruses infect or cause disease in humans.
A viral genome is the genetic material (DNA or RNA) that is present in a virus. It contains all the genetic information that a virus needs to replicate itself and infect its host. The size and complexity of viral genomes can vary greatly, ranging from a few thousand bases to hundreds of thousands of bases. Some viruses have linear genomes, while others have circular genomes. The genome of a virus also contains the information necessary for the virus to hijack the host cell's machinery and use it to produce new copies of the virus. Understanding the genetic makeup of viruses is important for developing vaccines and antiviral treatments.
Wasting syndrome is a condition characterized by significant weight loss and muscle wasting, often accompanied by weakness and decreased appetite. It can be caused by various underlying medical conditions, including HIV/AIDS, cancer, tuberculosis, and other chronic infections or diseases that cause chronic inflammation. In some cases, wasting syndrome can also result from severe malnutrition or gastrointestinal disorders that affect nutrient absorption.
The diagnostic criteria for wasting syndrome vary depending on the underlying cause, but generally, it is defined as a significant loss of body weight (typically more than 10% of body weight) and muscle mass over a period of several months. In addition to weight loss and muscle wasting, individuals with wasting syndrome may also experience fatigue, weakness, decreased immune function, and impaired physical functioning.
Wasting syndrome can have serious consequences on an individual's health and quality of life, and it is often associated with increased morbidity and mortality. Treatment typically involves addressing the underlying cause of the wasting syndrome, as well as providing nutritional support to help individuals regain weight and muscle mass.
Chicken anemia virus (CAV) is a small, non-enveloped DNA virus that belongs to the family *Circoviridae* and genus *Gyrovirus*. It primarily infects chickens and causes a variety of clinical signs, including severe anemia, immunosuppression, and runting in young birds.
The virus is highly contagious and can be spread through horizontal transmission via feces, contaminated equipment, or vertically from infected breeder hens to their offspring. CAV infection can lead to significant economic losses in the poultry industry due to decreased growth rates, increased mortality, and reduced egg production.
In addition to its impact on the poultry industry, CAV has also been used as a vector for gene delivery in biomedical research. Its small genome size and ability to infect a wide range of avian species make it an attractive candidate for vaccine development and gene therapy applications.
Porcine Postweaning Multisystemic Wasting Syndrome (PPWS) is not a widely recognized or officially established medical term in human healthcare. However, it is a significant disease in swine (pig) farming. Here's the definition of PPWS from a veterinary medicine perspective:
Porcine Postweaning Multisystemic Wasting Syndrome (PPWS) is a complex and poorly understood disease affecting piglets after weaning. The syndrome is characterized by wasting, diarrhea, and various secondary symptoms impacting multiple body systems. The primary cause of PPWS remains elusive, but it is believed to be associated with a combination of infectious agents (such as viruses and bacteria) and non-infectious factors (like management practices, environmental conditions, and genetics). The disease has a significant economic impact on the swine industry due to reduced growth rates, increased mortality, and decreased feed conversion efficiency in affected piglets.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.