Let’s Not Get Hysterical. Yet.

Nymph and Adult Asian Long-horned Tick, Haemaphysalis longicornis, on a US dime

The reporting on the spread of the invasive Asian Long-horned Tick, verges on the hysterical. “Vicious species of tick.” “Bloodthirsty hordes.” “Ravenous swarms.” Sounds like a lousy (sorry) Grade-B horror flick. But there are some scary aspects to this recently invasive species.

First, unlike native North American ticks, this species can reproduce parthenogenetically; it can clone itself. Enthusiastically. In Surrey Count, North Carolina, the State Veterinarian reports, a cow died of acute anemia, effectively sucked dry by more than a thousand ticks. It’s the fourth confirmed cattle fatality since 2018. The invasive species has been reported in about a quarter of North Carolina’s counties, and in eight eastern states. The State Vet said,:

It is an aggressive biter and frequently builds intense infestations on animals causing great stress, reduced growth and production, and blood loss. The tick can reproduce parthenogenetically (without a male) and a single fed female tick can create a localized population.

Talk about Malthusian population growth curves! A female tick cloning itself can only create more female ticks, who can create still more female ticks. A well-fed female can drop 2,000 eggs over two to three weeks. And not just domestic animals:

We present the case summary of the first human recognized to have been bitten by the Haemaphysalis longicornis tick in the United States, which occurred in New York State. Subsequent field studies confirmed that this tick was present in multiple geographic locations near the patient’s residence, including on manicured lawns.

So it’s well-established in North America, and breeds like bacteria. That’s concerning.

Second, and perhaps even more concerning, on its native turf it is host and vector to an amazing array of diseases. They include Rickettsia japonica, the bacteria behind Oriental spotted fever, and Theileria orientalis, a parasite that causes cattle theileriosis. Its also known to harbor relatives to pathogens present in the US, including bacteria that cause anaplasmosis and ehrlichiosis, the parasite that causes babesiosis, and the Powassan virus. ​None of those ghastly dreadfuls have been found in the Longicornis found in the U.S. so far, but still.

There’s a 2015 report that a newer and scarier viral disease can be transmitted by this tick species. SFTS, short for Severe Fever with Thrombocytopenia Syndrome, was first identified in China in 2009 and is marked by fever, vomiting, hemorrhaging, and organ failure. Reported fatality rates fall between 6 percent and 30 percent. But before we all panic, remember there would have to be a person or animal carrying SFTS in the states, and a Longicornis tick would have to feed on that person before the disease could establish itself here. No impossible, but not an immediate threat. A good reason to keep the CDC fully funded, though.

So, yeah, a dangerous invasive species, but can we scale back on the anthropomorphism and “savage tick-clone armies” business?