Named after the Zika (translated overgrown) Forest in Uganda, by 2007 it had spread to Micronesia, Central and South America and the Caribbean.  This is a Flavivirus carried by Aedes mosquitoes such as Aedes aegypti and Aedes albopictus thus it is referred to as an arbovirus.  The RNA containing virus is similar to West Nile Virus, Yellow Fever Virus, and Dengue Fever.  The natural (sylvatic) cycle involves hosts such as monkeys but identification of other host animals is far from complete. West Nile Virus is associated with many different bird hosts and the rapid dissemination of the virus in the United  States starting in 2001 is partly due to these avian hosts. Some think the Zika Virus will not disseminate as quickly but worry that it will become established in the Southern US where these mosquito vectors are present.

The disease in humans is similar to Dengue Fever but mild and non-fatal  and over 75% of infections are asymptomatic.  However the main concern is for pregnant women where there is evidence the infected mother can pass the virus in utero to the newborn leading microcephaly and brain damage.  Travel warnings may be forthcoming.

​The bacterium Yersinia pestis that is responsible for potentially severe infections sometimes referred to as the Black Death and responsible for the elimination of a large percentage of the population in Europe during the Middle Ages still exists in endemic areas such as prairie dog towns out west.  In its natural (sylvatic) cycle, the bacterium is maintained in flea vectors and small rodents.  The bacterium is often associated with prairie dog towns where transmission of the bacterium to prairie dogs by fleas  results in amplification and further spread of the bacterium.  The result is often death of prairie dogs which leads to infection of predator species such as the black-footed ferret.  In addition with loss of the prairie dog, decline in both the ferret and prairie nesting birds such as the Mountain Plover and Meadowlarks often occur.  Mountain plovers prefer dry habitat with short grass and bare ground for nesting. Loss of prairie dog colonies leads to a decline in nesting habitat for these birds.