One of the biggest concerns for pet owners is illness. Often, dogs or pets don’t show obvious symptoms, so it can be difficult to tell when they’re sick. Now, anaplasmosis, a bacterial disease transmitted by black-legged ticks, has begun to spread rapidly in various regions of California. In any case, and despite the fear, direct transmission between dogs and people is extremely rare.
Recent data show that of 59,215 dogs tested, 714 tested positive
The main route of transmission for both dogs and humans is the bite of an infected tick. In California, recent data show that of 59,215 dogs tested, 714 tested positive, indicating sustained growth between 2021 and 2024. The tick must be attached to a host for a period of time to transmit the bacteria.
Experts say direct contact with the blood of an infected animal is not a significant route of transmission to humans
In any case, and despite the above, specialists warned that the prevalence in dogs should be taken as an indicator of risk for humans. However, according to the data, direct contact with the blood of an infected animal is not a significant route of transmission to humans. This is because dogs tend to be more exposed to tick bites and undergo diagnostic testing more frequently.
“When you see a sustained increase in the dog population, we know there’s also a growing threat to public health”
More than half of California’s counties are now classified as high-risk areas for exposure to ticks carrying anaplasmosis and Lyme disease. It’s important to know that after a tick bite, it can take up to 14 days for signs and symptoms of ehrlichiosis and anaplasmosis to begin showing. “When you see a sustained increase in the dog population, we know there’s also a growing threat to public health,” explained Brad Ryan, a veterinarian with Antech Diagnostics.
In Los Angeles, considered an intermediate risk area, tests showed that around 1.21% of dogs tested positive in 2024
As for expert recommendations, the best way to prevent these infections is to avoid tick bites. In Los Angeles, considered an intermediate risk area, tests showed that around 1.21% of dogs tested positive in 2024, a figure double the 0.5% recorded five years earlier. Using tick repellent, thoroughly checking your entire body after being outdoors, and properly removing ticks are your best defenses against tick-borne diseases. While data from California are available, the Companion Animal Parasite Council estimated that the official numbers do not fully reflect the reality.
The data in Los Angeles showed that the phenomenon is not limited to the northern part of the state
Different species of the Ehrlichia bacteria cause ehrlichiosis. The Lone Star tick, found in the south-central, southeastern, and eastern coastal states of the United States, is the primary carrier of the bacteria that causes ehrlichiosis. The data in Los Angeles showed that the phenomenon is not limited to the northern part of the state, where there have historically been more cases, but is also beginning to manifest in southern areas. The signs and symptoms of ehrlichiosis and anaplasmosis are generally the same, although they tend to be more severe in ehrlichiosis. The symptoms of ehrlichiosis and anaplasmosis vary greatly from person to person, or from animal to animal. They can range from mild fever, chills, loss of appetite to nausea, vomiting, diarrhea, and more.
Avoiding these areas prevents infection and the disease from spreading
Ticks live close to the ground, in wooded or bushy areas. Therefore, it is recommended to avoid these areas and, above all, to be well-informed about the areas where bites are most common. Remember that avoiding these areas prevents infection and the disease from spreading further among residents.
