Bug Blog

Disease-Carrying Ticks In Mexico May Soon Be Arriving In The USA

Ticks, and the diseases that they transmit to humans and animals, are not typically associated with the country of Mexico. Americans are well aware of the tick-borne disease crisis that is occuring within their own country, but many Americans fail to realize that other countries also have issues with ticks, although the diseases that they transmit differ from country to country. However, it seems that there is something about the United States that ticks like, as many ticks that are native to Mexico are relocating to the southwest US. A study published last month found that recent tick outbreaks in Mexico City may soon be coming to America as well.Logo

In the US, lyme disease is, by far, the most common tick-borne disease, but this is not the case in Mexico. The disease known as Rock Mountain spotted fever is the most common tick-borne disease in Mexico. In fact, Rocky Mountain spotted fever is the most common tick-borne disease in all of North America. Rocky Mountain spotted fever causes flu-like symptoms, and if the disease is not treated in time, death can result. This disease occurs after ticks transmit a bacteria known as Rickettsia rickettsii to humans through their bite. Rocky Mountain spotted fever is relatively rare in the US, but several different tick species carry the disease-causing bacteria. In the eastern US, the disease is spread by the American dog tick. In Mexico and the southwest US, the disease is spread by the brown dog tick. And in the Rocky Mountain region, the disease is spread by the aptly named Rocky Mountain wood tick. Although all three of these ticks can transmit Rocky Mountain spotted fever, only the brown dog tick can survive for long periods indoors. This makes Rocky Mountain spotted fever much more common in Mexico and the southwest US relative to other regions. In between the years of 1997 and 2007, Rocky Mountain spotted fever caused a total of 80 documented deaths in the Mexican state of Sonora, and several recent outbreaks have occured in Arizona. In 2008, Rocky Mountain spotted fever claimed more Mexican and American victims than usual, and 80 percent of local dogs in one Mexican region tested positive for the disease-causing bacteria.

To many researchers, this evidence indicates that Mexican brown dog ticks have been moving into the southwestern US from Mexico. Also, Mexican authorities have not contained the disease, so there is no telling how significant recent brown tick migrations into the US have been. Not long ago, American officials managed to contain outbreaks of the disease in Arizona, and hopefully future interventions by public health officials will prove effective at containing the disease in the southwest.

If you live in the western region of America, do you consider yourself to be safe from tick-borne diseases?