Zika, another false red alert for a new disease

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Zika virus (ZIKV) is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947. The infections, known as Zika fever, often causes no or only mild symptoms. Zika virus is related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses.^[2] The illness it causes is similar to a mild form of dengue fever,^[2] is treated by rest,^[3] and cannot yet be prevented by drugs or vaccines.^[3] There is a possible link between Zika fever and microcephaly in newborn babies by mother-to-child transmission,^[4]^[5]^[6] as well as a stronger one with neurologic conditions in infected adults, including cases of the Guillain–Barré syndrome.^[7]

Zika virus is transmitted by daytime-active mosquitoes as its vector and has been isolated from a number of species in the genus Aedes, and in arboreal mosquitoes. Studies show that the extrinsic incubation period in mosquitoes is about 10 days.^[22] mosquito population capable of carrying the Zika virus has been found in a Capitol Hill neighborhood of Washington, D.C., and genetic evidence suggests they survived at least the last four winters in the region. The study authors conclude that mosquitos are adapting for persistence in a northern climate.^[27] nother sexually-transmitted case was reported in 2016 in the USA.^[33] Thus far, Zika fever has been a relatively mild disease of limited scope, with only one in five persons developing symptoms, with no fatalities, but its true potential as a viral agent of disease is unknown.^[22] In the worst affected region of Brazil, approximately 1 percent of newborns are suspected of being microcephalic.^[53] [Because of the 2016 Olympic Games in Brazil, there is a strong incentive for under-reporting Wiki.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Guillain–Barré syndrome is rare, at one to two cases per 100,000 people every year.[1]

This autoimmune disease is caused by the body's immune system mistakenly attacking the peripheral nerves and damaging their myelin insulation. Sometimes this immune dysfunction is triggered by an infection. The diagnosis is usually made based on the signs and symptoms, through the exclusion of alternative causes, and supported by tests such as nerve conduction studies and examination of the cerebrospinal fluid.

In those with severe weakness, prompt treatment with intravenous immunoglobulins or plasmapheresis, together with supportive care, will lead to good recovery in the majority. Some may experience ongoing difficulty with walking, painful symptoms, and some require long-term breathing support. In total, about a third of people with Guillain–Barré syndrome continue to be able to walk.^[2] Once the weakness has stopped progressing, it persists at a stable level ("plateau phase") before improvement occurs. The plateau phase can take between two days and six months, but the most common duration is a week.^[2] Pain-related symptoms affect more than half, and include back pain, painful tingling, muscle pain and pain in the head and neck relating to irritation of the lining of the brain.^[2] The autonomic or involuntary nervous system, which is involved in the control of body functions such as heart rate and blood pressure, is affected in two thirds of people with Guillain–Barré syndrome, but the impact is variable.^[2]Twenty percent may experience severe blood-pressure fluctuations and irregularities in the heart beat, sometimes to the point that the heart beat stops and requiring pacemaker-based treatment.^[1] Other associated problems are abnormalities in perspiration and changes in the reactivity of the pupils.^[4] Autonomic nervous system involvement can affect even those who do not have severe muscle weakness.^[4] Wiki.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Proof that Zika virus causes fetal microcephaly or other neurological abnormalities has not been established. Epidemiologic studies to track cases of microcephaly during 2016 are ongoing in Brazil and in countries affected later, such as Colombia…. So far, no known mutation of the virus has been found to account for its spread or the possible link with neurologic disorders…. Typical clinical signs and symptoms of Zika virus disease include low grade fever, rash, joint and muscle pain, and conjunctivitis. These occur after a 3-12 day incubation period. Importantly, 80% of Zika virus infections are asymptomatic. Diagnostic antibody tests can give false positive results because of cross reaction against related viruses such as dengue. No commercial diagnostic tests are available…. In the 20% of patients who are symptomatic the clinical illness usually resolves in 2-7 days. http://www.bmj.com/content/352/bmj.i781?etoc= BMJ, 8 Feb 2016

[1] “An association with neurological disorders such as Guillain-Barré syndrome, although not proved to be causal, has been reported in French Polynesia, Brazil, and El Salvador.” BMJ listed below.