The Linnaean Society of New York
General Meeting Minutes
January 10, 2023
(Note: This meeting and presentation took place online, via Zoom, due to social distancing protocols prompted by the ongoing COVID-19 pandemic.)
At 7:00 pm, President Rochelle Thomas called the meeting of the Society to order.
President Thomas reminded everyone of the annual meeting on March 14th at the Liederkranz Club. The Society will be hosting this event in person for the first time since 2020 and will celebrate this year’s Eisenmann medalist, Dr. Scott Edwards. This event is for members and their guests only, so if you still need to renew your membership, now is the time.
The board is in the final stages of preparing a survey to learn what our membership values and prioritizes. Please be on the lookout for an email with the link to the survey.
President Thomas then announced the passing of Alan Messer. Alan was a former Linnaean Society president (2005-2007), recording secretary (1999-2001 and 2003-2005), and longtime Central Park birder. His artwork graced many of the Linnaean Society publications.
Motion 1: President Thomas announced the results of a new-member vote, which passed with 170 votes of approval and 0 opposed.
The Society welcomed the following four new members:
Samari Weinberg sponsored by Karen Asakawa
Beth Labush sponsored by Ken Chaya
Corey Farwell sponsored by Ken Chaya
Ian Bell sponsored by Miriam Rakowski
Motion 2: President Thomas then announced the result of the online vote to approve the minutes of the December 2022 members’ meeting. The vote passed with 176 votes of approval and 2 abstentions.
At 7:03 pm, President Thomas introduced the speaker, Dr. Meredith VanAcker.
Dr. Meredith VanAcker is a disease ecologist working as a George E. Burch Postdoctoral Fellow under the Smithsonian’s Global Health and Movement of Life programs. Her work integrates methods from wildlife movement and ecology to examine how animals’ responses to land-use change impact the distribution and prevalence of zoonotic pathogens and infectious disease risk for humans. Dr. VanAcker completed her Ph.D. at Columbia University, where she worked with wildlife populations in New York City to determine the ecological drivers of urban tick-borne disease risk. She now examines multi-species movement and contact to examine how these interactions determine the risk for pathogen spillover in Nairobi, Kenya.
Wildlife Movement and Infectious Disease Emergence in Complex Urban Ecosystems
Dr. VanAcker began by defining terms used in disease ecology:
- Infectious Disease: Illnesses caused by pathogenic microorganisms, including bacteria, viruses, parasites, or fungi, that can be spread directly or indirectly from one person to another or from an animal to a human.
- Zoonotic Spillover Event: Describes the transmission from vertebrate animals to humans.
- Vector: Living organisms that can transmit infectious pathogens between humans or from animals to humans. Common examples are mosquitoes, flies, or ticks.
- Reservoir Host: The habitat in which the infectious agent normally lives, grows, and multiplies. Reservoirs include humans, animals, and the environment. The reservoir may or may not be the source from which an agent is transferred to a host. Infection is typically asymptomatic or non-lethal to the host.
The majority of emerging human infectious diseases are zoonotic. It’s estimated that 71% of the infectious diseases experienced by humans originated from animals, and emerging zoonoses in the future are most likely to be viruses. Today’s discussion focuses on the global burden of zoonotic diseases, the current status, and where we are heading.
The annual mortality rate of viral disease epidemics is 3.3 million lives. Researchers predict disease events using a global database and predictors that span human activities, like deforestation and agricultural intensification, and animal characteristics, like biodiversity and phylogenetic proximity. Areas with high biodiversity and land-use change correlate with disease emergence.
Equally important, massive inequities in healthcare access and in the degree of surveillance of infectious diseases exist between high- and middle- to low-income countries, exacerbating the burden of zoonotic diseases. In addition to human losses, zoonotic outbreaks have significant economic impacts. Putting prevention strategies into place could reduce the likelihood of outbreaks. For example, a 10% reduction in infection can reduce the expected deaths by 300,000 people and save up to $2 trillion USD annually.
There are multiple pathways to zoonotic spillover, where pathogens move from animals into humans. These pathways describe the ecological interactions that underlie the spillover event.
- Pathogens released through an animal’s natural excretion.
- The distribution of reservoir hosts and the intensity of infection within those hosts.
- Pathogens transmitted through a vector, like a mosquito or tick, that acquires the infection when it feeds on the host.
- Human exposure to environmental pathogens through butchering or eating infected meat, or through being bitten by an infected vector.
All factors must align, both in space and time, for spillover to occur. Environmental changes impact these pathways and can accelerate spillover events.
- Land-use change is one of the dominant ways the pathways can be disturbed.
- Climate change can alter the range and survival of vectors such as mosquitos, which can then spread mosquito-borne disease more broadly.
- Agricultural intensification changes pathogen infection dynamics through inflating animal densities by holding many livestock in a small space. It also presents more opportunities for human exposure through slaughter.
- Wildlife trade can import known and unknown pathogens into naive populations, altering the pathogen movement and geographical distribution.
Dr. VanAcker’s focus is on the impacts of land-use change, specifically on zoonotic spillover. One of the dominant types of land-use change is urbanization.
Cities are home to 55% of the world’s population; this number is expected to increase to 60% by 2015. Urbanization can facilitate zoonotic disease emergence and spread through land-use alteration, environmental stressors, and human population dynamics. Environmental stressors like food scarcity or clustering of wildlife around resources can increase susceptibility to infection. With land-cover conversion, humans may contact animals more frequently along edge habitats, potentially increasing the transmission probability.
In the last twenty years, New York City has experienced increased vector-borne diseases from ticks. The most prevalent tick-borne diseases in New York are anaplasmosis, babesiosis, and Lyme disease. On its own, a tick only moves one meter vertically in space. However, one deer can feed up to 500 ticks, and each tick can lay up to 2000 eggs, making deer vital for tick population establishment.
Nairobi, Kenya, is very different from New York City. Nairobi’s population is estimated at 8.5 million, and is growing at roughly 4% each year. Further, 60% of the population occupies only 6% of the land, primarily slum areas. The slum population is expected to double in the next 15 years, creating a high demand for animal products. This will bring livestock into close contact with humans, making zoonotic surveillance very important for the city.
Nairobi’s elevation gradient encompasses both socio-economic and ecological variation. High-income areas align with higher elevation as well as high tree cover. In these areas, there is more biodiversity, lower human density, and less livestock. Conversely, in low-income areas, there is higher human and livestock density in addition to more land use by humans, as well as rats and raccoons living in close association with people. This close contact and attendant potential for pathogen transmission are what Dr. VanAcker will be focusing on in her upcoming work.
Wildlife that interacts closely with humans, livestock, and livestock waste may be exposed to more antimicrobial-resistant bacteria. A team studying multidrug-resistant E Coli across many different wildlife groups in Nairobi found that fruit bats and seed-eating birds were significantly more likely to carry multidrug-resistant E Coli than other wildlife, including rodents and primates. This data implies that wildlife and livestock are coming into close contact.
Dr. VanAcker’s upcoming book will focus on how livestock contact with wildlife affects virus transmission in Nairobi’s rapidly developing urban area. Her research includes using lightweight proximity sensors to study fruit bats, house sparrows, and Marabou storks. She is assessing the frequency of indirect human-to-wildlife contact through fruiting trees and manure piles near households. Oral and rectal swabs and blood samples will be obtained from these animals to determine the diversity of viruses being shared and spread around the city by investigating their genomics. Looking at this social network will provide information to the community and public health officials working in urban development. Dr. VanAcker’s publication will be released in a year and a half.
In summary, urban zoonotic surveillance and prevention should be addressed with a multi-hazard lens. By studying the ways that diseases are spreading, scientists can determine how to manage zoonotic hazards in cities.
Equally important is the education of the human population. It is vital that we continue working towards preventing deforestation, making urban growth more sustainable, and reducing agricultural expansion so that pathogens circulating in nature remain contained in nature. This isn’t just for the benefit of humans, as it is also extremely critical for wildlife conservation and health.
The evening ended with a rousing Q and A session hosted by Vice President Gabriel Willow, after which the Linnaean Society thanked Dr. VanAcker for sharing her fascinating research.