West Nile Virus: Case Update

As of 8/20,2018, ODH is reporting 5 human West Nile virus (WNV) cases, including 1 fatality, and 2 asymptomatic WNV viremic blood donors in Ohio.  Additionally, ODH received a report today from the Ohio Department of Agriculture of an equine case in an unvaccinated horse.  WNV activity in mosquitoes continues to rise and we have now seen indications of virus activity in 52 Ohio counties so far this year.

The graph below shows where we are this year with infection rates in mosquitoes compared to 2012, a high WNV activity year (red dotted line), and 2016, a relatively normal WNV activity year (green dashed line):

In addition to WNV, ODH is also reporting 6 LAC cases and 2 unspecified California virus cases.  The rainfall we’ve had this summer has continuously filled tree holes and containers with water, creating ideal conditions for tree hole mosquitoes (vectors of LAC virus) to breed. For more information about arbovirus cases and surveillance data, see the current Ohio arbovirus surveillance update at http://www.odh.ohio.gov/arboupdate, updated earlier today.

There are quite a few weeks left in this  mosquito season and cases can occur into October, so it is very important to continue your community and public education efforts focusing on personal protection and source reduction. Also, please call the Zoonotic Disease Program (ZDP) at (614) 752-1029 if you have any questions.

A New Tick Species Found in the United States

You probably have heard about this new tick invasive in the U.S. First detected in late 2017 in NJ. Recent reports are that it is spreading rapidly. See news clips as below:

“For the first time in 50 years, a new tick species has arrived in the United States — one that in its Asian home range carries fearsome diseases.

The Asian long-horned tick, Haemaphysalis longicornis, is spreading rapidly along the Eastern Seaboard. It has been found in seven states and in the heavily populated suburbs of New York City.

For now, the new arrivals are considered a greater threat to livestock.

Known in Australia as bush ticks and in New Zealand as cattle ticks, long-horned ticks can multiply rapidly and suck so much blood from a young animal that it dies.

The longhorn tick is known to carry several diseases that infect hogs and cattle in Asia. So far, ticks examined in the U.S. do not carry any diseases that can infect humans, but the USDA says the insects frequently form large infestations that cause great stress on warm-blooded host animals, reducing its growth and production. A severe infestation can kill the animal due to blood loss.


Officials said female longhorn ticks reproduce asexually and a single tick can reproduce and lay 2,000 eggs after feeding on a host. Cattle, pets, small mammals, birds and humans are all potential hosts.


In 2017, officials discovered the first longhorn tick population in the United States feeding on large numbers of sheep in Mercer County, New Jersey. It has also been found in Arkansas, New York, West Virginia and Virginia. Tests by the National Veterinary Services Laboratory in Ames, Iowa, have confirmed the presence of an Asian — or longhorn — tick on a wild deer in Centre County on Tuesday. It is the first confirmed sighting of the parasite in Pennsylvania.”