Incidence of Tick-Borne Illness Fatal to Cats Increasing in N.C.
Veterinarians at North Carolina State University have seen a recent increase in cases of a tick-transmitted infectious disease that, without proper treatment, can be fatal to cats.
The disease, Cytauxzoonosis (pronounced sight-O-zO-un-Osis), is related to malaria and is caused by the parasite Cytauxzoon felis, (C. felis) which is found in ticks carried by host bobcats. The most common symptoms of infection are lack of energy and appetite, usually accompanied by a profound fever. Some cats develop a yellow discoloration of the skin and the whites of the eyes.
According to Dr. Adam Birkenheuer, associate professor of internal medicine at NC State, C. felis was first discovered in Missouri in the mid-1970s and for years was only documented in the south central region of the United States. Prior to the late 1990s, Cytauxzoonosis had never been reported in North Carolina.
“Between 1998 and 2004 we saw a series of 34 cases from North and South Carolina and Virginia,” Birkenheuer says. “When it was first recognized in our region, we might see one case per year in the Veterinary Teaching Hosptial (VTH). Now we see one-to-two cases per week during the peak months (May-July) with many other consults that are not referred. We have already seen three cases in the past two weeks, which is pretty remarkable for an infection that is not ‘supposed to be here.’”
The disease seems to occur in “hotspots” with some households having several cats acquiring the infection. The majority of cases seen at NC State’s VTH have come from Pittsboro, Southern Pines and coastal North Carolina from Morehead City down to the Southport area. These are not the only affected areas, however; cases have also come from other parts of the Triangle including Wake Forest, Rolesville and eastern Raleigh.
“There are a couple of reasons we believe we are seeing this increase in Cytauxzoonosis,” Birkenheuer says. “One is the change in the distribution of the tick species that can transmit the infection to domestic cats. One of the tick species in particular, Amblyomma americanum, has a geographic distribution that is rapidly expanding north and east. The other reason we’re seeing the increase is that some cats survive the infection and can act as a reservoir leading to the infection of more cats.”
Testing for the disease is relatively simple and a veterinarian can usually make the diagnosis by examining a blood smear or cells from infected tissues like lymph nodes, liver or spleen. In some cases, a DNA test can be used to confirm infection.
The best protection against Cytauxzoonosis is to keep cats indoors and use a treatment that is approved to kill ticks on cats (some canine products can be toxic to cats.) The use of anti-tick products alone may not guarantee the prevention of infection. A veterinarian should be consulted immediately if an owner detects any signs of the disease in the pet.