Current Activities

Vaccination Workshop

In August 2009 we ran a Workshop on Great Ape Vaccination as part of the Symposium on Great Ape Health in Entebbe, Uganda. Participants from great ape habituation sites discussed disease threats and vaccination priorities, and then drew up an action plan for vaccination research and implementation.

NCEAS Working Group

VaccinApe members are leading a working group on Efficient Wildlife Vaccination at the National Center for Ecological Analysis and Synthesis. This group is both studying both the role of ape social network structure in past outbreaks of Ebola virus and developing and parameterizing simulation models to be used in finding efficient strategies for vaccination.

Adjuvant Trials

Adjuvants are compounds that enhance immune response to vaccination. VaccinApe partner Integrated Biotherapeutics (IBT) is currently screening multiple adjuvants to find the one that produces the maximal mouse immune response to vaccination with their virus-like particle (VLP) vaccine. The two best adjuvants will then be used in chimpanzee trials (see below).

Fecal Antibody Assays

Gorilla dung piles collected in 2008 in Central Africa Republic are currently being assayed by IBT in order to detect previous exposure to Ebola virus and viruses that act as vectors in available Ebola vaccines (i.e. adenovirus). The dung piles will also be assayed for a variety of human respiratory pathogens (i.e. measles, RSV, influenza) in order evaluate whether gorilla habituation for tourism has increased human disease transmission risk.

Captive Ebola Vaccine Trials

In early 2010 IBT’s, VLP vaccine will be used to vaccinate captive chimpanzees. This vaccine has been tested extensively in monkeys; therefore, the chimp trials will not involve exposure to Ebola virus. Rather, they will evaluate whether the vaccine is safe (i.e. causes no serious side-effects) and immunogenic (i.e. produces a serum antibody response similar to monkeys who survived Ebola challenge). Comparison of fecal to serum antibodies will also be used to validate fecal antibody methods for quantifying vaccination success in the field.

Measles Vaccination Pilot Study

In late 2009 we will conduct a pilot study in which wild gorillas habituated to human presence are vaccinated against measles using a hypodermic dart. The measles vaccine has already been given to hundreds of millions of children and thousands of captive chimpanzees and gorillas. Therefore, objectives of the study are to: 1) find darting methods that avoid injury and\or stress to gorillas, 2) quantify induced stress using fecal hormone analyses, 3) quantify immunization success using fecal antibody analyses, and 4) ground truth methods for vaccine cold chain and sample transport.

Veterinary Licensing of Ebola Vaccine

We are about to initiate the process of applying to the US Department of Agriculture for a conditional veterinary license for IBT’s Ebola vaccine. Such a license is not strictly necessary for use of the vaccine on apes in Africa. We have decided to seek one because USDA licensing will provide clear evidence that the vaccine has been tested and manufactured under rigorous quality and safety standards. Legal advice donated by Arnold & Porter.

Once the vaccine has been licensed with USDA (hopefully late 2010) we will conduct a field pilot study on habituated gorillas. Fecal antibody assays developed by VaccinApe will be used to quantify both rates of successful vaccination and levels of induced stress.

Past Activities

Captive Oral Bait Trials

In late 2007 and early 2008 we tested oral baits on gorillas, chimpanzees, and orangutans at the Wolfang Koehler Primate Research Center at the Leipzig Zoo in Germany. Developed by the German vaccine manufacturer IDT Biologika, the baits did not contain any vaccine but were merely used to see which colors (red, yellow) or scents (mango, banana, fig) were most attractive to the captive apes.

Field Oral Bait Trials

In the summer of 2008 we conducted a brief pilot study in which we presented baits (without vaccine) to habituated gorillas at the World Wildlife Fund’s (WWF) Bai Hokou tourism site in the Dzanga-Sangha Protected Areas, Central African Republic. The gorillas sniffed and gummed the baits, none were swallowed. Our conclusion was that a bait gorillas would eat could likely be found, but doing so would require an intensive research effort.

Dung Sampling

In the summer of 2008 we collaborated with WWF to collect dung from almost 100 gorillas in the Dzanga-Sangha Protected Areas, Central African Republic. These samples have already been assayed by the University of Albama for evidence of antibodies indicating infection to SIV.

Scientific Advisory Committee

In August 2008 The University of Pittsburgh’s Center for Biosecurity in Baltimore hosted a meeting of our Scientific Advisory Committee. Attendees included leading experts from primatology, ape conservation, Ebola vaccinology, and the human and veterinary vaccine manufacturing industries. At the meeting we discussed the pros and cons of different vaccines and methods of vaccine delivery and developed a strategy for vaccinating wild apes against Ebola and other disease threats.

Future Activities

Oral Bait Delivery

Oral vaccination provides the potential to both recurrently vaccinate habituated apes without the risks of stress or injury and to vaccinate large numbers of unhabituated apes. A major roadblock to reaching this potential is finding a good oral bait delivery system: both the bait itself and the time, location, and manner in which the bait is delivered. We would like to conduct extensive oral baiting studies on both gorillas and chimpanzees.

Oral Vaccine Formulation and Trials

Converting vaccine from injected to oral delivery requires reformulation of the vaccine to be heat stable, packaging of the vaccine in a waterproof bait matrix, and animal trials to demonstrate that the vaccine retains immunogenicity in the new formulation and packaging. We would like to pursue this process for a limited set of pathogens that are of greatest threat to apes in the wild.