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Leptospirosis is a blood infection caused by the bacterium Leptospira [8] that can infect humans, dogs, rodents and many other wild and domesticated animals. [8] Signs and symptoms can range from none to mild ( headaches , muscle pains , and fevers ) to severe ( bleeding in the lungs or meningitis ). [ 5 ]
In particular, L. interrogans cells survive and multiply at an optimal rate in the kidneys. The pathogen mostly spreads through the bodily fluids of infected animals. [17] Rats are the primary carrier of leptospirosis but do not present any symptoms, transmitting the pathogen through urine, which is able to persist in freshwater. [27]
An unusual feature of leptospiral LPS is that it activates host cells via TLR2 rather than TLR4. [27] The unique structure of the lipid A portion of the LPS molecule may account for this observation. [28] Finally, the LPS O antigen content of L. interrogans differs in an acutely infected versus a chronically infected animal. [29]
A zoonosis (/ z oʊ ˈ ɒ n ə s ɪ s, ˌ z oʊ ə ˈ n oʊ s ɪ s / ⓘ; [1] plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite, or prion) that can jump from a non-human vertebrate to a human.
Different viruses can infect all the organs and tissues of the body and the outcomes range from mild or no symptoms, to life-threatening diseases. [5] Humans cannot be infected by plant or insect viruses, but they are susceptible to infections with viruses from other vertebrates. These are called viral zoonoses or zoonotic infections. [6]
1839: Theodor Schwann [43] and Matthias Jakob Schleiden elucidated the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory. 1855: Rudolf Virchow stated that new cells come from pre-existing cells by cell division (omnis cellula ex cellula).
For this reason, these viruses are called positive-sense RNA viruses. [35] In other RNA viruses, the RNA is a complementary copy of mRNA and these viruses rely on the cell's or their own enzyme to make mRNA. These are called negative-sense RNA viruses. In viruses made from DNA, the method of mRNA production is similar to that of the cell.
Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is ...