Cat health

The average life expectancy for male indoor cats at birth is around 12 to 14 years,[89] with females usually living a year or two longer.[90] However, there have been reports of cats reaching into their 30s,[91] with the oldest known cat, Creme Puff, dying at a verified age of 38.[92] Feline life expectancy has increased significantly in recent decades.[93] Having a cat neutered or spayed confers some health benefits, since castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer.[94] The lifespan of feral cats is hard to determine accurately, although one study reported a median age of 4.7 years, with a range between 0 to 8.3 years. Infectious diseases, also known as transmissible diseases or communicable diseases comprise clinically evident illness (i.e., characteristic medical signs and/or symptoms of disease) resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism. In certain cases, infectious diseases may be asymptomatic for much or even all of their course in a given host. In the latter case, the disease may only be defined as a "disease" (which by definition means an illness) in hosts who secondarily become ill after contact with an asymptomatic carrier. An infection is not synonymous with an infectious disease, as some infections do not cause illness in a host.[1] Infectious pathogens include some viruses, bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are the cause of disease epidemics, in the sense that without the pathogen, no infectious epidemic occurs. The term infectivity describes the ability of an organism to enter, survive and multiply in the h st, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts.[2] Transmission of pathogen can occur in various ways including physical contact, contaminated food, body fluids, objects, airborne inhalation, or through vector organisms.[1] Infectious diseases are sometimes called "contagious" when they are easily transmitted by contact with an ill person or their secretions (e.g., influenza). Thus, a contagious disease is a subset of infectious disease that is especially infective or easily transmitted. Other types of infectious/transmissible/communicable diseases with more specialized routes of infection, such as vector transmission or sexual transmission, are usually not regarded as "contagious," and often do not require medical isolation (sometimes loosely called quarantine) of victims. However, this specialized connotation of the word "contagious" and "contagious disease" (easy transmissibility) is not always respected in popular use. A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions. A genetic disorder may or may not be a heritable disorder. Some genetic disorders are passed down from the parents' genes, but others are always or almost always caused by new mutations or changes to the DNA. In other cases, the same disease, such as some forms of cancer, may be caused by an inherited genetic condition in some people, by new mutations in other people, and by nongenetic causes in still other people. Some types of recessive gene disorders confer an advantage in certain environments when only one copy of the gene is present.