Zika Virus ( ZIKV ) is the latest unexpected " arrival " in the Americas of an " arbovirus " - transmitted by " arthropods ", like mosquitoes. Only a small number of these viruses cause medically important illness, especially dengue, and also chikungunya ( each in other Forum threads ).


ZIKV was first isolated from a monkey in the Zika forest of Uganda about 70 years ago. Until recently it wasn’t thought to be much of a threat - only a fifth of infected people fall ill, usually with mild FAR ( Fever, Arthralgia = joint pains, and Rash ).


The interest - and worry - is that it MAY cause birth defects ( such as microcephaly = small head with brain damage ) and rarely nervous system problems ( including paralysis ) in adults.


There is now a ZIKV epidemic, and a public health emergency, in Brazil ( estimates between half a million to over 1.3 million cases ) - where the Olympic Games are due to be held in August this year - also involving elsewhere in South America, Central America, and the Caribbean. Urban crowding, international travel, and other human behaviour have probably contributed.


ZIKV is transmitted by the bite of an infected female mosquito - Aedes aegypti most commonly. This mosquito is not present in the UK ( too cold ),but three cases have this month been diagnosed in travellers from Colombia, Suriname, and Guyana. It’s not spread from person to person.


There have been recent epidemics in Micronesia and French Polynesia, but only isolated cases in the Philippines and elsewhere in South East Asia.


Once again, as with Ebola, a virus infection has emerged unexpectedly. This time - NO specific treatment ( just supportive nursing care and relief of symptoms ) ; NO vaccines ( they will be developed but who to vaccinate and at what cost ? ) ; even diagnosis is difficult and expensive.


Attacking disease-carrying mosquitoes and personal protection ( such as repellent use ) are therefore all the more important. Aedes mosquitoes, which also transmit dengue, mainly bite during the day ( unlike those transmitting malaria ). ZIKV infection is mild in most cases, but obviously of concern - especially if pregnant in South and Central America. It's not yet fully understood.