Researchers from Washington State University have identified a protein that plays a crucial role in the establishment and transmission of the harmful bacteria that causes anaplasmosis, a tick-borne disease. The study focused on the zoonotic tick-borne agent Anaplasma phagocytophilum and its interaction with ticks. The researchers discovered a protein secreted by the bacteria that is essential for its survival and spread within tick cells. This finding could lead to a better understanding of how these bacteria persist and spread within ticks, potentially opening avenues for strategies to prevent the transmission of other tick-borne diseases to humans and animals.
Dr. Jason Park, the corresponding author of the study, explained that blocking this protein could stop ticks from spreading the bacteria to humans, effectively breaking the transmission cycle. Tick-borne diseases pose a growing threat to humans and livestock in the United States and other countries. While previous research has focused on the pathogens in mammalian hosts, limited attention has been given to understanding their survival and propagation within ticks.
Anaplasma phagocytophilum is the causal agent of anaplasmosis, a disease transmitted to humans primarily through tick bites. The black-legged tick and western black-legged tick are the main carriers of the disease. Although anaplasmosis is treatable with antibiotics, it can cause symptoms such as fever, headache, chills, muscle aches, and, in severe cases, illness. According to the Centers for Disease Control and Prevention, the number of anaplasmosis cases has been increasing in the United States, reaching 5,655 in 2019.
Ticks become infected with the bacteria when feeding on an infected animal. Inside the tick, the goal for the bacteria is to infect the salivary glands, where it will accumulate and wait to be transmitted to the next mammal the tick feeds on, continuing the cycle. The researchers discovered that the bacteria use a specific secreted protein called AteA to inject and reprogram host cells in ticks. This protein interacts with the cortical actin, the structural scaffolding of the host cell, and is crucial for the bacteria’s survival in ticks.
Although the researchers have identified AteA as the first secreted protein specifically important for ticks, they believe that there are likely other proteins involved in the bacteria’s survival within ticks. The researchers are now investigating how the bacteria regulates the expression of proteins like AteA during both mammalian and tick infections, as well as how they distinguish between the two hosts.
Dr. Park believes that instead of treating a person after they have been infected with Anaplasma phagocytophilum, efforts should be focused on preventing ticks from spreading the bacteria. By targeting the protein that allows the bacteria to survive in ticks, it may be possible to reduce the spread of tick-borne diseases to humans. Further research in this area could lead to the development of strategies and interventions to effectively control these diseases and mitigate their impact on human and animal health.
