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Parasitic bronchitis, also known as hoose, husk, or verminous bronchitis, [1] is a disease of sheep, cattle, goats, [2] and swine caused by the presence of various species of parasite, commonly known as lungworms, [3] in the bronchial tubes or in the lungs. It is marked by cough, dyspnea, anorexia and constipation.
JSRV is the virus that is the cause of the contagious lung tumors in sheep called ovine pulmonary adenocarcinoma (OPA). The disease has also been called "jaagsiekte", after the Afrikaans words for "chase" (jaag) and "sickness" (siekte), to describe the respiratory distress observed in an animal out of breath from being chased, indicating the breathing difficulty experienced by infected sheep.
The tracheal system branches into progressively smaller tubes, here supplying the crop of the cockroach. Scale bar, 2 mm. The word trachea is used to define a very different organ in invertebrates than in vertebrates. Insects have an open respiratory system made up of spiracles, tracheae, and tracheoles to transport metabolic gases to and from ...
First described in 1954 by Bjorn Sigurdsson in Iceland, [6] Maedi-visna virus was the first lentivirus to be isolated and characterized, accomplished in 1957 by Sigurdsson. [6] [7] [8] Maedi (Icelandic mæði 'dyspnoea') and visna (Icelandic visna 'wasting' [9] or 'shrinking' of the spinal cord) refer to endemic sheep herd conditions that were only found to be related after Sigurdsson's work.
Tumors form in nose and are contagious. ENTV targets the respiratory system in ovine, specifically the upper-airway epithelial cells. [6] Oncogenesis occurs in the nasal turbinate cells [8] A typical oncogenic virus will cause a mutation in a host cell, causing the transformation of host cells from a protooncogene into an oncogene.
The virus usually spreads via the respiratory system, and sometimes spreads through abraded skin. It is most likely to occur in crowded stock. Sources of the virus include cutaneous lesions, saliva, nasal secretions and faeces. There are two types of the disease: the papulo-vesicular form and the nodular form (stone pox).
The distribution of M. capillaris is determined by the geographic location of the snail and slug intermediate hosts the parasite uses in its life cycle. [2] The natural intermediate host of M. capillaris is a species of terrestrial snails belonging to the Genus Trochoidea, and juvenile T. seetzenii snails are the most susceptible to the parasitic infection. [4]
Scrapie and other transmissible spongiform encephalopathies are caused by prions. [19] Prions were determined to be the infectious agent because transmission is difficult to prevent with heat, radiation and disinfectants, the agent does not evoke any detectable immune response, and it has a long incubation period of between 18 months and 5 years. [20]