Myelitis is acute, but the retroviruses (such as HIV and HTLV) can cause chronic myelitis. Poliomyelitis, or gray matter myelitis, is usually caused by infection of anterior horn of the spinal cord by the enteroviruses (polioviruses, enteroviruses (EV) 70 and 71, echoviruses, coxsackieviruses A and B) and the flaviviruses (West Nile, Japanese encephalitis, tick-borne encephalitis). On the other hand, transverse myelitis or leukomyelitis, or white matter myelitis, are often caused by the herpesviruses and influenza virus. It can be due to direct viral invasion or via immune mediated mechanisms. Bacterial myelitis includes "Mycoplasma Pneumoniae", which is a common agent for respiratory
Development of the human body the 19th century, when it was 15 for girls and 16 for boys. This can be due to any number of factors, including improved nutrition resulting in rapid body growth, increased weight and fat deposition, or exposure to endocrine disruptors such as xenoestrogens, which can at times be due to food consumption or other environmental factors. Puberty which starts earlier than usual is known as precocious puberty, and puberty which starts later than usual is known as delayed puberty. Notable among the morphologic changes in size, shape, composition, and functioning of the pubertal body, is the development of secondary sex