Arboviruses are short for arthropod-borne viruses. These viruses are transmitted to animals and humans by arthropods such as mosquitoes and ticks. In Brazilian forests, mosquitoes are a major vector (a carrier that transfers an infectious agent from one host to another). Zika virus, yellow fever, dengue, West Nile virus and chikungunya are all types of arboviruses that affect both animals and humans.

You’ve probably heard of both the Zika virus and West Nile virus, both of which are transmitted by mosquitoes. Zika virus and West Nile virus are both prevalent in Brazil and are known to cause serious health issues for animals and humans alike. Of course, such infections are not limited to Brazil. Numerous countries around the globe have reported evidence of these mosquito-transmitted infections, and West Nile virus is the leading cause of mosquito-borne disease in the continental United States. However, Brazil hosts the greatest variety of arboviruses in the world and is therefore an important location to conduct our research. There is still much to learn about these viruses that are of concern to both conservation and public health.

Animals become infected with arboviruses when mosquitoes carrying any of these viruses bite them, transmitting it from mosquito to animal. Not only might animals become sick from these viruses, they may also transmit the viruses to humans. If a mosquito bites an infected animal and then bites a human, that person could then become infected. Many Brazilian cities are home to free-living wildlife, zoos, or animal rescue centers, many of which house threatened or endangered primates. These animals are exposed to the same arboviral vectors (i.e., mosquitoes) as are the urban human population, which underscores the need to better understand the epidemiology of arboviruses in wildlife.

We are evaluating the prevalence and the risk of arbovirus infections in primates housed in these urban areas and training zoo staff to continue prospective surveillance. One question we are asking is whether mosquitoes might serve as a bridge for reverse spillback; i.e., can infections from humans affect wildlife? Exposure to Zika, dengue and chikungunya viruses may lead to non-human primate population declines, just as recent yellow fever outbreaks have led to howler monkey declines. In North America, West Nile virus has led to declines in wild birds such as sparrows, cardinals, woodpeckers. Data collection is underway to see if similar effects are present in Brazil.

In partnership with the Animal Health Department of Piauí State, Human Health Department of Piauí State, and the Federal University of Piauí State, we are also surveying equines, chickens, and free-living wild birds in municipalities within Piauí state where West Nile virus infections in humans have been confirmed.

Conservation medicine isn’t just about the science. During past outbreaks of yellow fever, humans have killed primates, believing that monkeys are the main transmitters of the disease. We conduct outreach in local communities to teach that many viruses that cause diseases are transmitted by mosquitoes, and that wildlife are victims of these diseases, just as humans are. For example, in our study, we observed that the lowest prevalence of arbovirus in humans was found in communities that lived in forests alongside free-living monkeys. This is because mosquitoes have opportunities to bite a variety of animals, not just humans. This shows that the biodiversity protects people.

Educational materials have been developed for students and adults that explain that primates have a fundamental role in preserving their forest habitat, which in turn keeps people, who rely on the forest, healthy as well. You can view examples of such materials here.

Dr. Catenacci is also working with local health and environmental professionals to educate them on the best practices for keeping people safe from these viruses without harming wildlife. A class on the identification of mosquitoes was held at the Federal University of Piauí with vet students, zoo technicians, forest engineers, and agronomy students. Additional classes are planned.

Primates can serve as disease sentinels, providing warnings to the human population that arboviruses are present in an area. Training professionals at zoos and animal rescue/rehabilitation centers is therefore very important. Dr. Catenacci developed and distributed education materials and a course on epidemic surveillance for zookeepers, research center staff, and local university students. In addition, she has provided several talks to zookeepers on this topic during her field research season.

For the West Nile virus survey in Piauí state, outreach materials were developed for rural communities, health professionals, and veterinarians. The network that has developed as a result of these outreach efforts will assist with a quick response to any future outbreaks in this region of Brazil.

Our goals are to evaluate the diversity and prevalence of arbovirus infections in primates and wild birds and investigate the role of mosquitos in the transmission of the arboviruses at the wildlife–human interface in both rural and urban areas. In order to achieve these goals, we will:

1) Further study the prevalence of arboviruses in primates, equines, wild birds, and mosquitoes in both cities and rural areas of Brazil;
2) Study mosquitoes that live near captive primates to better understand the prevalence of arboviruses in mosquitoes;
3) Continue outreach to visitors and staff at zoos and rescue centers as well as provide community outreach to residents and health care professionals;
4) Provide training courses on mosquito identification to undergraduate students.

The integration of a One Health approach in this research will result in findings that will be used to develop preventive actions to protect both people and animals.

Osmaikon Lobato, biologist and graduate student at the Federal University of Piauí, has been working on his master's degree with bird samples and vectors collected throughout the state of Piauí, northeastern Brazil. He is trying to understand the relationship of wild birds in the West Nile virus circulation in the state and identifying the potential vector for the virus. This research is directed by Dr. Catenacci in partnership with the Saint Louis Zoo and is part of the surveillance of the circulation of the West Nile virus in Piauí. It also includes the participation of the Agricultural Defense Agency of Piauí, State Secretariat of Health of Piauí, and the Central Laboratory of Public Health of Piauí.

In order to address the scarcity of information on this topic in Brazil, this study aims to investigate the presence of beta-lactamase-producing bacteria in wild birds and domestic animals belonging to the Caatinga Biome.

Kelly Souza, a graduate student at the Federal University of Pará working under the direction of Dr. Catenacci and in partnership with the Saint Louis Zoo, has developed a master’s research project to learn more. Her goals are to identify if there are antibiotic-resistant bacteria in wild and domestic animals in Piauí. Samples of feces from goats, cattle, pigs, horses, and domestic and wild birds were collected in five cities and are being analyzed for bacterial resistance to several widely used antibiotics. This research takes a One Health approach involving a multidisciplinary collaboration of experts in microbiology, veterinary medicine, pharmacy science, and agriculture.