Ovine pulmonary adenocarcinoma (OPA), also known as ovine pulmonary adenomatosis, or jaagsiekte, is a chronic and contagious disease of the lungs of sheep and goats. OPA is caused by a retrovirus called jaagsiekte sheep retrovirus (JSRV).
Ovine pulmonary adenocarcinoma (OPA), also known as ovine pulmonary adenomatosis, or jaagsiekte, is a chronic and contagious disease of the lungs of sheep and goats. OPA is caused by a retrovirus called jaagsiekte sheep retrovirus (JSRV).
The disease has a long incubation period, and therefore signs usually occur in adult animals (over 2 years of age). [1] Clinical signs resemble a non-specific progressive pneumonia, including poor body condition and, particularly after exercise, respiratory difficulty. [2] Unless a concurrent lung infection is present, affected sheep continue to eat. [2] The only sign specific to OPA is a watery nasal discharge, consisting of lung fluid produced by the affected lung tissue; lifting the hind legs of the animal above the level of its head will cause large volumes of this fluid to flow from the nostrils. [2]
There are no reliable tests for the diagnosis of OPA in live animals which are suitable for use on farms, [3] so diagnosis can only be confirmed at necropsy (post-mortem examination). On necropsy, lungs are interspersed with multifocal tumors. Some of these are small discrete nodules and others will involve the entire half of a lung lobule. [2] JSRV acutely transforms the lung epithelia into cancerous cells, with type-2 pneumocytes and club cells being the likely target for JSRV transformation. The tumors have overactive secretory functions, which are a hallmark of OPA.[ citation needed ]
The retroviral antigen levels of JSRV are very high in OPA tumors and can be detected in the lung secretions of infected sheep. It is thought that infected animals secrete the virus before showing signs, so the virus is easily spread within flocks.[ citation needed ]
OPA has been found in most countries where sheep are farmed, with the exception of Australia and New Zealand. OPA has been eradicated in Iceland. [4]
No breed or sex of sheep appears to be predisposed to OPA. [5] Most affected sheep show signs at 2 to 4 years of age. [4]
OPA is not a notifiable disease, and therefore it is difficult to assess its prevalence. [4]
OPA was first described in the UK in 1888, [4] and described in detail in South Africa in 1891. [6] The disease was initially known as jaagsiekte [jɑːχˈsiktə] , a word derived from Afrikaans, meaning "chasing sickness", so called because animals are in respiratory distress as if they are out of breath from being chased. [6] It has also been known as sheep pulmonary adenomatosis and ovine pulmonary carcinoma. [7]
OPA has been used as an animal model for human lung cancer, because OPA is histologically similar to human adenocarcinoma in situ of the lung. [8]
Dolly the sheep, the first mammal successfully cloned from an adult somatic cell, was euthanized after it was confirmed that she had OPA. [9]
Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged airway cells gain the ability to multiply unchecked, causing the growth of a tumor. Without treatment, tumors spread throughout the lung, damaging lung function. Eventually lung tumors metastasize, spreading to other parts of the body.
Adenocarcinoma is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both. Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist. Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma. Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them.
Betaretrovirus is a genus of the Retroviridae family. It has type B or type D morphology. The type B is common for a few exogenous, vertically transmitted and endogenous viruses of mice; some primate and sheep viruses are the type D.
Opa or OPA may refer to:
Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.
Jaagsiekte sheep retrovirus (JSRV) is a betaretrovirus which is the causative agent of a contagious lung cancer in sheep, called ovine pulmonary adenocarcinoma.
Bovine malignant catarrhal fever (BMCF) is a fatal lymphoproliferative disease caused by a group of ruminant gamma herpes viruses including Alcelaphine gammaherpesvirus 1 (AlHV-1) and Ovine gammaherpesvirus 2 (OvHV-2) These viruses cause unapparent infection in their reservoir hosts, but are usually fatal in cattle and other ungulates such as deer, antelope, and buffalo. In Southern Africa the disease is known as snotsiekte, from the Afrikaans.
Ovine rinderpest, also commonly known as peste des petits ruminants (PPR), is a contagious disease primarily affecting goats and sheep; however, camels and wild small ruminants can also be affected. PPR is currently present in North, Central, West and East Africa, the Middle East, and South Asia. It is caused by small ruminants morbillivirus in the genus Morbillivirus, and is closely related to, among others, rinderpest morbillivirus, measles morbillivirus, and canine morbillivirus. The disease is highly contagious, and can have an 80–100% mortality rate in acute cases in an epizootic setting. The virus does not infect humans.
Visna-maedi virus from the genus Lentivirus and subfamily Orthoretrovirinae, is a retrovirus that causes encephalitis and chronic pneumonitis in sheep. It is known as visna when found in the brain, and maedi when infecting the lungs. Lifelong, persistent infections in sheep occur in the lungs, lymph nodes, spleen, joints, central nervous system, and mammary glands; The condition is sometimes known as ovine progressive pneumonia (OPP), particularly in the United States, or Montana sheep disease. White blood cells of the monocyte/macrophage lineage are the main target of the virus.
Bovine leukemia virus (BLV) is a retrovirus which causes enzootic bovine leukosis in cattle. It is closely related to the human T‑lymphotropic virus type 1 (HTLV-I). BLV may integrate into the genomic DNA of B‑lymphocytes as a DNA intermediate, or exist as unintegrated circular or linear forms. Besides structural and enzymatic genes required for virion production, BLV expresses the Tax protein and microRNAs involved in cell proliferation and oncogenesis. In cattle, most infected animals are asymptomatic; leukemia is rare, but lymphoproliferation is more frequent (30%).
Adenocarcinoma in situ (AIS) of the lung —previously included in the category of "bronchioloalveolar carcinoma" (BAC)—is a subtype of lung adenocarcinoma. It tends to arise in the distal bronchioles or alveoli and is defined by a non-invasive growth pattern. This small solitary tumor exhibits pure alveolar distribution and lacks any invasion of the surrounding normal lung. If completely removed by surgery, the prognosis is excellent with up to 100% 5-year survival.
NK2 homeobox 1 (NKX2-1), also known as thyroid transcription factor 1 (TTF-1), is a protein which in humans is encoded by the NKX2-1 gene.
Fetal adenocarcinoma (FA) of the lung is a rare subtype of pulmonary adenocarcinoma that exhibits tissue architecture and cell characteristics that resemble fetal lung tissue upon microscopic examination. It is currently considered a variant of solid adenocarcinoma with mucin production.
Large cell lung carcinoma with rhabdoid phenotype (LCLC-RP) is a rare histological form of lung cancer, currently classified as a variant of large cell lung carcinoma (LCLC). In order for a LCLC to be subclassified as the rhabdoid phenotype variant, at least 10% of the malignant tumor cells must contain distinctive structures composed of tangled intermediate filaments that displace the cell nucleus outward toward the cell membrane. The whorled eosinophilic inclusions in LCLC-RP cells give it a microscopic resemblance to malignant cells found in rhabdomyosarcoma (RMS), a rare neoplasm arising from transformed skeletal muscle. Despite their microscopic similarities, LCLC-RP is not associated with rhabdomyosarcoma.
Mucinous cystadenocarcinoma of the lung (MCACL) is a very rare malignant mucus-producing neoplasm arising from the uncontrolled growth of transformed epithelial cells originating in lung tissue.
Adenocarcinoma of the lung is the most common type of lung cancer, and like other forms of lung cancer, it is characterized by distinct cellular and molecular features. It is classified as one of several non-small cell lung cancers (NSCLC), to distinguish it from small cell lung cancer which has a different behavior and prognosis. Lung adenocarcinoma is further classified into several subtypes and variants. The signs and symptoms of this specific type of lung cancer are similar to other forms of lung cancer, and patients most commonly complain of persistent cough and shortness of breath.
Squamous-cell carcinoma (SCC), also known as epidermoid carcinoma, comprises a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the lining of the respiratory and digestive tracts.
The enzootic nasal tumor virus of the betaretrovirus genus is a carcinogenic retrovirus that causes enzootic nasal adenocarcinoma in sheep and goats. Strain ENTV-1 is found in sheep and strain ENTV-2 is found in goats. The virus causes tumor growth in the upper nasal cavity and is closely related to JSRV which also causes respiratory tumors in ovine. The disease, enzootic nasal adenocarcinoma is common in North America and is found in sheep and goats on every continent except New Zealand and Australia. There are more than 27 betaretroviruses similar to ENVT and JSRV in the ovine genome. In the future, research on ENTV may become important in studying viruses that cause human lung cancer.
Enzootic nasal adenocarcinoma is a fatal, malignant neoplastic, infectious disease in sheep and goats. It is caused by the Enzootic nasal tumor virus, a retrovirus similar to Jaagsiekte sheep retrovirus, which causes a similar disease, also in sheep and goats called Ovine pulmonary adenocarcinoma (OPA). Symptoms include nasal discharge, dyspnea, facial deformity, and weight loss. Like OPA, the disease has a very long incubation period and is invariably fatal.
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