COLLEGE STATION, Texas – Adela Oliva Chavez, Texas A&M AgriLife Research entomologist and assistant professor in the Department of Entomology at the Texas A&M College of Agriculture and Life Sciences, Bryan-College Station, grew up in a farming family in Honduras and learned at a young age how ticks can impact animal and human health.
His experiences around beef and dairy production and as a playful kid have shaped his interest in science and continue to fuel his passion for providing scientific breakthroughs that can prevent or treat tick-borne diseases like tick disease. Lyme and human granulocytic anaplasmosis in humans and Texas bovine fever, or bovine babesiosis, in cattle.
“I have seen cows unable to stand due to severe anemia, so I was interested from a very young age in doing something about this problem,” she said. “I would go outside to play and come home covered in ticks, and at the time, there wasn’t a lot of information about tick-borne illnesses. “
Her sister developed a severe fever after a discharge, and the diagnosis was a mosquito-borne virus, but Chavez now suspects it was linked to a tick bite.
A career in solving human and animal diseases. Chavez focused his early education and career on agriculture and animal health. Since then, she has been committed to finding scientific solutions and creating tools to fight tick-borne diseases that cause significant problems for humans and animals, as well as economic losses around the world.
Now she is on the front line in the fight against diseases spread by these parasites. His latest research was recently published in Nature Communications. She was also named to a multidisciplinary group of 50 young scientists from across the country who focus on various global threats related to the impacts of animal diseases on human health.
According to the Centers for Disease Control and Prevention, the risk of pathogen transfer from parasite to host has increased with tick populations over the past two decades. The total number of tick-borne disease cases more than doubled to 50,865 in 2019 from 22,257 in 2004.
Lyme disease, the most common tick-borne disease in humans, is estimated to affect 476,000 Americans each year, based on insurance records. That translates to costs of between $ 712 billion and $ 1.3 billion, according to the John Hopkins Bloomberg School of Public Health.
In animals, bovine anaplasmosis, a disease caused by bacteria transmitted by several species of ticks, is estimated to cost ranchers $ 300 million per year. The overall impact of ticks on livestock operations is likely to be even higher, as it is difficult to measure the impact of parasites on cattle weight, reduced milk production, aborted calves or other health problems that reduce production.
Chavez said the number of people infected with vector-borne pathogens carried by ticks is also likely much higher than CDC estimates due to misdiagnosis and low reporting rates in mild cases. Bites can lead to major health problems for healthy hosts and poor health outcomes for immunocompromised.
Win the war against ticks. The bite site is Chavez’s new focus. His research presented in Nature Communications has shown that changes occur at the molecular level as ticks feed and impact the host’s immune response and ability to fight pathogens.
Feeding ticks can be a long process that can take several days, she said. At some point during feeding, ticks transmit the pathogen by repeating a cycle of injecting saliva and sucking blood.
This transmission sequence is where Chavez thinks the tick’s microRNA and protein are transferred to the host to manipulate the immune response in a way that allows the tick to feed. A reduced immune response prevents bodily responses such as blood clotting, wound closure, and any direct immune counterattack against the parasite.
“These pathogens do more than just ride the tick,” Chavez said. “Pathogens and ticks have a symbiotic relationship that dates back over 100 million years. It really is an arms race. The tick bites, and the host’s immune response wants to kill the tick, and there is a fight. The pathogen that has adapted to use the tick as a vessel works with it symbiotically in this fight to disrupt the host’s immune response and allow the tick to continue feeding.
By learning which cell types or immune signaling pathways are activated during the tick bite response, Chavez and other scientists hope to improve the immune response to stop or treat infection with tick-borne pathogens. .
“The end product would be a vaccine that would make the host immune to the tick and kill the tick before it transmits a pathogen,” she said. “My goal is to find tools that prevent disease and are affordable for individuals and small farms in the United States and around the world. “
Reduce the impact of ticks. There are hundreds of species of ticks and ticks can be found on all continents. All ticks feed on blood, but there is great diversity among species, including their feeding processes and the diseases they carry.
The available vaccines target certain tick species of economic importance to livestock, but their effectiveness may be limited when controlling ticks of different strains, Chavez said.
The US Department of Agriculture and its Animal and Plant Health Inspection Service are funding a project to develop better vaccines. Chavez began work on this project in 2019 and is purifying material that she hopes to begin testing at USDA facilities in October or November.
Chavez and his fellow entomological scientists at Texas A&M AgriLife are also studying epigenetic similarities and differences in tick populations. By determining the epigenetic markers found in local ticks, health officials can track the characteristics, behaviors and pathogens of these populations.
For example, how and where the tick locates on vegetation while waiting for a host, or “looking for”, appears to be inherited from the tick’s parents. Different tick populations in the south and north of the country search differently, Chavez said.
The difference in the research is a hypothesis as to why Lyme disease is not as prevalent in Texas as it is in the north of the country, including Minnesota, where partner scientists are exchanging data found during ‘tick surveys.
“Lyme disease is present here and across the South, but ticks don’t go as high on vegetation as strains of the same tick species in the Midwest,” Chavez said. “They don’t spread to humans and don’t acquire as many pathogens.”
Studying these epigenetic markers could also be essential for prevention, she said.
Tick-focused research is increasingly important, Chavez said, as the species expand their range due to warmer weather conditions and a higher number of potential hosts like deer. These efforts are also critically important to prevent invasive tick species, such as the cattle fever ticks found in parts of South Texas that are particularly deadly to livestock, from inflicting catastrophic losses on the United States- United.
“Ticks are not a new problem, but they have received more attention over the past 20 years, particularly their effects on humans,” Chavez said. “But whether it is affecting food sources, livelihoods or human health, it is important that we learn more about ticks to reduce their impact.”