Circovirus
Wasting Syndrome
Porcine Postweaning Multisystemic Wasting Syndrome
Circoviridae
Swine
Porcine respiratory and reproductive syndrome virus
Porcine Reproductive and Respiratory Syndrome
Colostrum
Viral Vaccines
Bird Diseases
Weaning
Polymerase Chain Reaction
Psittaciformes
Torque teno virus
Open Reading Frames
Molecular Sequence Data
Identification of a novel GC-rich 113-nucleotide region to complete the circular, single-stranded DNA genome of TT virus, the first human circovirus. (1/377)
The sequence data (H. Okamoto et al., Hepatol. Res. 10:1-16, 1998) of a newly discovered single-stranded DNA virus, TT virus (TTV), showed that it did not have the terminal structure typical of a parvovirus. Elucidation of the complete genome structure was necessary to understand the nature of TTV. We obtained a 1.0-kb amplified product from serum samples of four TTV carriers by an inverted, nested long PCR targeted for nucleotides (nt) 3025 to 3739 and 1 to 216 of TTV. The sequence of a clone obtained from serum sample TA278 was compared with those registered in GenBank. The complete circular TTV genome contained a novel sequence of 113 nt (nt 3740 to 3852 [=0]) in between the known 3'- and 5'-end arms, forming a 117-nt GC-rich stretch (GC content, 90.6% at nt 3736 to 3852). We found a 36-nt stretch (nt 3816 to 3851) with an 80.6% similarity to chicken anemia virus (CAV) (nt 2237 to 2272 of M55918), a vertebrate circovirus. A putative SP-1 site was located at nt 3834 to 3839, followed by a TATA box at nt 85 to 90, the first initiation codon of a putative VP2 at nt 107 to 109, the termination codon of a putative VP1 at nt 2899 to 2901, and a poly(A) signal at nt 3073 to 3078. The arrangement was similar to that of CAV. Furthermore, several AP-2 and ATF/CREB binding sites and an NF-kappaB site were arranged around the GC-rich region in both TTV and CAV. The data suggested that TTV is circular and similar to CAV in its genomic organization, implying that TTV is the first human circovirus. (+info)Evidence that a plant virus switched hosts to infect a vertebrate and then recombined with a vertebrate-infecting virus. (2/377)
There are several similarities between the small, circular, single-stranded-DNA genomes of circoviruses that infect vertebrates and the nanoviruses that infect plants. We analyzed circovirus and nanovirus replication initiator protein (Rep) sequences and confirmed that an N-terminal region in circovirus Reps is similar to an equivalent region in nanovirus Reps. However, we found that the remaining C-terminal region is related to an RNA-binding protein (protein 2C), encoded by picorna-like viruses, and we concluded that the sequence encoding this region of Rep was acquired from one of these single-stranded RNA viruses, probably a calicivirus, by recombination. This is clear evidence that a DNA virus has incorporated a gene from an RNA virus, and the fact that none of these viruses code for a reverse transcriptase suggests that another agent with this capacity was involved. Circoviruses were thought to be a sister-group of nanoviruses, but our phylogenetic analyses, which take account of the recombination, indicate that circoviruses evolved from a nanovirus. A nanovirus DNA was transferred from a plant to a vertebrate. This transferred DNA included the viral origin of replication; the sequence conservation clearly indicates that it maintained the ability to replicate. In view of these properties, we conclude that the transferred DNA was a kind of virus and the transfer was a host-switch. We speculate that this host-switch occurred when a vertebrate was exposed to sap from an infected plant. All characterized caliciviruses infect vertebrates, suggesting that the host-switch happened first and that the recombination took place in a vertebrate. (+info)Ultrastructure of porcine circovirus in persistently infected PK-15 cells. (3/377)
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)Electron microscopical observations of psittacine beak and feather disease in an Umbrella cockatoo (Cacatua alba). (4/377)
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. (5/377)
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. (6/377)
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. (7/377)
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 circoviruses: a review. (8/377)
Porcine circoviruses (PCV) are small nonenveloped DNA viruses containing a unique single-stranded circular genome. Previously, no recognized link was found between PCV infection of pigs and disease, and PCV was considered a nonpathogenic agent. Over the last 5 years, a "novel" PCV, designated PCV2, has been associated with various disease syndromes in pigs, primarily postweaning multisystemic wasting syndrome (PMWS). Pigs with PMWS have a variety of clinical signs, including debility, dyspnea, palpable lymphadenopathy, diarrhea, and pallor or icterus. Lesions associated with the presence of PCV2 in a variety of cell types include lymphohistiocytic to granulomatous interstitial pneumonia, hepatitis, nephritis, myocarditis, enteritis, and pancreatitis. The lesions of PMWS have been reproduced experimentally after inoculation of piglets with PCV2 cell culture isolates, although the full expression of the disease syndrome may require the presence of other agents such as porcine parvovirus or porcine reproductive and respiratory syndrome (PRRS) virus. Recent reports have linked PCV2 to other disorders in pigs, ranging from abortion and reproductive failure to "atypical" PRRS. Available data indicate high seroprevalence of antibodies to PCV2 worldwide. The diagnosis of PCV2-associated disease is based on the direct demonstration of PCV2 antigens or nucleic acid in affected tissues. PCV2 is now regarded as an important emerging pathogen. Although vertical transmission has been documented, the epidemiology of PCV2 infections is poorly understood, as is the role of the immune response in controlling or augmenting disease. (+info)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.
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.
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.
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.
Swine diseases refer to a wide range of infectious and non-infectious conditions that affect pigs. These diseases can be caused by viruses, bacteria, fungi, parasites, or environmental factors. Some common swine diseases include:
1. Porcine Reproductive and Respiratory Syndrome (PRRS): a viral disease that causes reproductive failure in sows and respiratory problems in piglets and grower pigs.
2. Classical Swine Fever (CSF): also known as hog cholera, is a highly contagious viral disease that affects pigs of all ages.
3. Porcine Circovirus Disease (PCVD): a group of diseases caused by porcine circoviruses, including Porcine CircoVirus Associated Disease (PCVAD) and Postweaning Multisystemic Wasting Syndrome (PMWS).
4. Swine Influenza: a respiratory disease caused by type A influenza viruses that can infect pigs and humans.
5. Mycoplasma Hyopneumoniae: a bacterial disease that causes pneumonia in pigs.
6. Actinobacillus Pleuropneumoniae: a bacterial disease that causes severe pneumonia in pigs.
7. Salmonella: a group of bacteria that can cause food poisoning in humans and a variety of diseases in pigs, including septicemia, meningitis, and abortion.
8. Brachyspira Hyodysenteriae: a bacterial disease that causes dysentery in pigs.
9. Erysipelothrix Rhusiopathiae: a bacterial disease that causes erysipelas in pigs.
10. External and internal parasites, such as lice, mites, worms, and flukes, can also cause diseases in swine.
Prevention and control of swine diseases rely on good biosecurity practices, vaccination programs, proper nutrition, and management practices. Regular veterinary check-ups and monitoring are essential to detect and treat diseases early.
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.
"Swine" is a common term used to refer to even-toed ungulates of the family Suidae, including domestic pigs and wild boars. However, in a medical context, "swine" often appears in the phrase "swine flu," which is a strain of influenza virus that typically infects pigs but can also cause illness in humans. The 2009 H1N1 pandemic was caused by a new strain of swine-origin influenza A virus, which was commonly referred to as "swine flu." It's important to note that this virus is not transmitted through eating cooked pork products; it spreads from person to person, mainly through respiratory droplets produced when an infected person coughs or sneezes.
Parvovirus, Porcine (PPV) is a single-stranded DNA virus that belongs to the family Parvoviridae and genus Parvovirus. It is a small, non-enveloped virus that primarily infects the rapidly dividing cells of piglets, particularly those in the intestinal epithelium and bone marrow.
PPV infection can cause a variety of clinical signs, including diarrhea, vomiting, lethargy, and loss of appetite, which can lead to severe dehydration and death in young piglets. The virus is highly contagious and can be spread through fecal-oral transmission or by ingesting infected material.
PPV infection is also associated with reproductive failure in sows, including stillbirths, mummified fetuses, and weak newborn piglets. This condition is known as Porcine Parvovirus Syndrome (PPVS). The virus can cross the placenta and infect developing fetuses, causing damage to their cardiovascular and nervous systems.
There are currently no specific treatments for PPV infection, but vaccination programs have been developed to prevent the spread of the virus in pig herds. Good biosecurity practices, such as isolating infected animals and thoroughly cleaning and disinfecting facilities, can also help reduce the risk of transmission.
Porcine Respiratory and Reproductive Syndrome Virus (PRRSV) is an enveloped, positive-stranded RNA virus belonging to the Arteriviridae family. It is the causative agent of Porcine Respiratory and Reproductive Syndrome (PRRS), also known as "blue ear disease" or "porcine reproductive and respiratory syndrome."
The virus primarily affects pigs, causing a wide range of clinical signs including respiratory distress in young animals and reproductive failure in pregnant sows. The infection can lead to late-term abortions, stillbirths, premature deliveries, and weak or mummified fetuses. In growing pigs, PRRSV can cause pneumonia, which is often accompanied by secondary bacterial infections.
PRRSV has a tropism for cells of the monocyte-macrophage lineage, and it replicates within these cells, leading to the release of pro-inflammatory cytokines and the development of the clinical signs associated with the disease. The virus is highly infectious and can spread rapidly in susceptible pig populations, making it a significant concern for the swine industry worldwide.
It's important to note that PRRSV has two distinct genotypes: Type 1 (European) and Type 2 (North American). Both types have a high degree of genetic diversity, which can make controlling the virus challenging. Vaccination is available for PRRSV, but it may not provide complete protection against all strains of the virus, and it may not prevent infection or shedding. Therefore, biosecurity measures, such as strict sanitation and animal movement controls, are critical to preventing the spread of this virus in pig populations.
Viral DNA refers to the genetic material present in viruses that consist of DNA as their core component. Deoxyribonucleic acid (DNA) is one of the two types of nucleic acids that are responsible for storing and transmitting genetic information in living organisms. Viruses are infectious agents much smaller than bacteria that can only replicate inside the cells of other organisms, called hosts.
Viral DNA can be double-stranded (dsDNA) or single-stranded (ssDNA), depending on the type of virus. Double-stranded DNA viruses have a genome made up of two complementary strands of DNA, while single-stranded DNA viruses contain only one strand of DNA.
Examples of dsDNA viruses include Adenoviruses, Herpesviruses, and Poxviruses, while ssDNA viruses include Parvoviruses and Circoviruses. Viral DNA plays a crucial role in the replication cycle of the virus, encoding for various proteins necessary for its multiplication and survival within the host cell.
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.
Porcine Reproductive and Respiratory Syndrome (PRRS) is a viral disease that affects pigs, causing reproductive failure in breeding herds and respiratory illness in young pigs. The disease is caused by the PRRS virus, which belongs to the family Arteriviridae.
In pregnant sows, PRRS can cause abortions, stillbirths, mummified fetuses, and weak or infertile offspring. In growing pigs, it can lead to pneumonia, reduced growth rates, and increased susceptibility to other infections. The virus is highly contagious and can spread rapidly within a herd through direct contact with infected pigs, aerosols, or contaminated fomites.
PRRS is a significant disease of global importance, causing substantial economic losses to the swine industry. Control measures include biosecurity practices, vaccination, and testing to detect and eliminate the virus from affected herds. However, there is no specific treatment for PRRS, and eradication of the virus from the pig population is unlikely due to its widespread distribution and ability to persist in infected animals and the environment.
Antibodies, viral are proteins produced by the immune system in response to an infection with a virus. These antibodies are capable of recognizing and binding to specific antigens on the surface of the virus, which helps to neutralize or destroy the virus and prevent its replication. Once produced, these antibodies can provide immunity against future infections with the same virus.
Viral antibodies are typically composed of four polypeptide chains - two heavy chains and two light chains - that are held together by disulfide bonds. The binding site for the antigen is located at the tip of the Y-shaped structure, formed by the variable regions of the heavy and light chains.
There are five classes of antibodies in humans: IgA, IgD, IgE, IgG, and IgM. Each class has a different function and is distributed differently throughout the body. For example, IgG is the most common type of antibody found in the bloodstream and provides long-term immunity against viruses, while IgA is found primarily in mucous membranes and helps to protect against respiratory and gastrointestinal infections.
In addition to their role in the immune response, viral antibodies can also be used as diagnostic tools to detect the presence of a specific virus in a patient's blood or other bodily fluids.
Colostrum is the first type of milk produced by the mammary glands of mammals (including humans) after giving birth. It is a yellowish, sticky fluid that contains a higher concentration of nutrients, antibodies, and immune-boosting components compared to mature milk. Colostrum provides essential protection and nourishment for newborns during their most vulnerable period, helping them establish a healthy immune system and promoting optimal growth and development. It is rich in proteins, vitamins, minerals, and growth factors that support the baby's gut health, brain development, and overall well-being. In humans, colostrum is usually produced in small quantities during the first few days after delivery, and its consumption by newborns is crucial for setting a strong foundation for their health.
Capsid proteins are the structural proteins that make up the capsid, which is the protective shell of a virus. The capsid encloses the viral genome and helps to protect it from degradation and detection by the host's immune system. Capsid proteins are typically arranged in a symmetrical pattern and can self-assemble into the capsid structure when exposed to the viral genome.
The specific arrangement and composition of capsid proteins vary between different types of viruses, and they play important roles in the virus's life cycle, including recognition and binding to host cells, entry into the cell, and release of the viral genome into the host cytoplasm. Capsid proteins can also serve as targets for antiviral therapies and vaccines.
A viral vaccine is a biological preparation that introduces your body to a specific virus in a way that helps your immune system build up protection against the virus without causing the illness. Viral vaccines can be made from weakened or inactivated forms of the virus, or parts of the virus such as proteins or sugars. Once introduced to the body, the immune system recognizes the virus as foreign and produces an immune response, including the production of antibodies. These antibodies remain in the body and provide immunity against future infection with that specific virus.
Viral vaccines are important tools for preventing infectious diseases caused by viruses, such as influenza, measles, mumps, rubella, polio, hepatitis A and B, rabies, rotavirus, chickenpox, shingles, and some types of cancer. Vaccination programs have led to the control or elimination of many infectious diseases that were once common.
It's important to note that viral vaccines are not effective against bacterial infections, and separate vaccines must be developed for each type of virus. Additionally, because viruses can mutate over time, it is necessary to update some viral vaccines periodically to ensure continued protection.
'Bird diseases' is a broad term that refers to the various medical conditions and infections that can affect avian species. These diseases can be caused by bacteria, viruses, fungi, parasites, or toxic substances and can affect pet birds, wild birds, and poultry. Some common bird diseases include:
1. Avian influenza (bird flu) - a viral infection that can cause respiratory symptoms, decreased appetite, and sudden death in birds.
2. Psittacosis (parrot fever) - a bacterial infection that can cause respiratory symptoms, fever, and lethargy in birds and humans who come into contact with them.
3. Aspergillosis - a fungal infection that can cause respiratory symptoms and weight loss in birds.
4. Candidiasis (thrush) - a fungal infection that can affect the mouth, crop, and other parts of the digestive system in birds.
5. Newcastle disease - a viral infection that can cause respiratory symptoms, neurological signs, and decreased egg production in birds.
6. Salmonellosis - a bacterial infection that can cause diarrhea, lethargy, and decreased appetite in birds and humans who come into contact with them.
7. Trichomoniasis - a parasitic infection that can affect the mouth, crop, and digestive system in birds.
8. Chlamydiosis (psittacosis) - a bacterial infection that can cause respiratory symptoms, lethargy, and decreased appetite in birds and humans who come into contact with them.
9. Coccidiosis - a parasitic infection that can affect the digestive system in birds.
10. Mycobacteriosis (avian tuberculosis) - a bacterial infection that can cause chronic weight loss, respiratory symptoms, and skin lesions in birds.
It is important to note that some bird diseases can be transmitted to humans and other animals, so it is essential to practice good hygiene when handling birds or their droppings. If you suspect your bird may be sick, it is best to consult with a veterinarian who specializes in avian medicine.
Weaning is the process of gradually introducing an infant or young child to a new source of nutrition, such as solid foods, while simultaneously decreasing their dependence on breast milk or formula. This process can begin when the child is developmentally ready, typically around 6 months of age, and involves offering them small amounts of pureed or mashed foods to start, then gradually introducing more textured and varied foods as they become comfortable with the new diet. The weaning process should be done slowly and under the guidance of a healthcare provider to ensure that the child's nutritional needs are being met and to avoid any potential digestive issues.
Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.
The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.
In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.
Psittaciformes is not a medical term but a taxonomic order that includes parrots, cockatoos, and related species. However, in a medical context, "psittacosis" is a relevant term that can be discussed.
Psittacosis is a zoonotic disease caused by the bacterium Chlamydia psittaci, which can infect humans through contact with infected birds or their droppings. The disease is also known as parrot fever or ornithosis. Psittacosis can cause flu-like symptoms in humans, such as fever, headache, muscle aches, and cough. In severe cases, it can lead to pneumonia and other complications.
Therefore, while "Psittaciformes" is not a medical term itself, the order includes many bird species that can carry and transmit Chlamydia psittaci, leading to the disease known as psittacosis in humans.
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.
Viremia is a medical term that refers to the presence of viruses in the bloodstream. It occurs when a virus successfully infects a host and replicates within the body's cells, releasing new viral particles into the blood. This condition can lead to various clinical manifestations depending on the specific virus involved and the immune response of the infected individual. Some viral infections result in asymptomatic viremia, while others can cause severe illness or even life-threatening conditions. The detection of viremia is crucial for diagnosing certain viral infections and monitoring disease progression or treatment effectiveness.
An open reading frame (ORF) is a continuous stretch of DNA or RNA sequence that has the potential to be translated into a protein. It begins with a start codon (usually "ATG" in DNA, which corresponds to "AUG" in RNA) and ends with a stop codon ("TAA", "TAG", or "TGA" in DNA; "UAA", "UAG", or "UGA" in RNA). The sequence between these two points is called a coding sequence (CDS), which, when transcribed into mRNA and translated into amino acids, forms a polypeptide chain.
In eukaryotic cells, ORFs can be located in either protein-coding genes or non-coding regions of the genome. In prokaryotic cells, multiple ORFs may be present on a single strand of DNA, often organized into operons that are transcribed together as a single mRNA molecule.
It's important to note that not all ORFs necessarily represent functional proteins; some may be pseudogenes or result from errors in genome annotation. Therefore, additional experimental evidence is typically required to confirm the expression and functionality of a given ORF.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.