My Research

There was a time when great apes thrived over much of mainland and insular Southeast Asia. Today the Orangutan (Genus Pongo) is the last surviving Asian great ape. My research currently focuses on this last remaining Asian ape. Orangutans once had a vast range that spread from China through the Indonesian archipelago to the Islands of Sumatra, Java and Borneo. At the turn of the 20th century an estimated 230,000 orangutans roamed the island of Borneo, and another 85,000 roamed the island of Sumatra (Rijksen and Meijaard, 1999) Today, however, there are an estimated 40,000 orangutans of the species Pongo pygmaeus left on the island of Borneo)and only 7,500 orangutans (Pongo abeli) on the island of Sumatra (Singleton et al., 2004).

Along with habitat loss and hunting, disease has been identified recently as a major threat to the survival of the great apes (Travis et al., 2008). Recent work by Pedersen and colleagues (Pedersen et al., 2007) indicates that the risk of extinction resulting from disease is probably greatly underestimated for most wildlife species. Given the realization that disease is a potentially major threat to primate-especially great ape-survival it is shocking to see how little information we have on primate disease processes. In fact, Nunn and Altizer (2006) note that: Given the numerous examples of pathogen-driven wildlife declines, a need exists for wildlife managers to quantify parasite occurrence in primates and obtain baseline knowledge on the parasites that are present, to gain an understanding of transmission modes and impacts on individual hosts, and to identify potential “reservoirs” of infection in other hosts that might cross-infect primates. (Nunn and Altizer, 2006:216) 

It is here that research like mine comes into play. My research focuses mostly on the natural transmission of diseases between humans and orangutans and orangutans and other primates. I examine the potential conservation implications of these disease transmission events to orangutan conservation as per the goals of conservation medicine.

What is Conservation Medicine

Conservation medicine like conservation biology before it has been called a “crisis discipline” (Otsfeld et al., 2002), with the ultimate objective of developing a better understanding of how environmental and health crises in humans and other animals are related. According to Otsfeld et al. (2002:18), conservation medicine is a new multidisciplinary field with four main goals which are to study:  

  1. “human-induced and natural changes in climate, habitat structure and land use;
  2. pathogens, parasites and pollutants;
  3. biodiversity and health within animal communities; and
  4. [the] health of humans.” 

Emerging Infectious Diseases (EIDs) and Conservation

The study of emerging infectious diseases (EIDs) or reemerging diseases are seen as important areas of conservation medicine (Dazak and Cunningham, 2002). EIDs are diseases that have recently increased in incidence, have recently expanded in geographic or host range, are newly recognized, or are caused by newly evolved pathogens (Dazak and Cunningham, 2002:40).

Of the 1407 known human pathogens, 58% are zoonotic in origin (Cook and Karesh, 2008) and we share more diseases with great apes than any other group of animals (Cranfield et al., 2002).  Of 415 primate parasites, 119 are also known to infect humans (Pedersen et al., 2005). Zoonoses can be defined as diseases and infections which naturally occur in animals that can be transmitted to humans (Coatney, 1971). As humans have encroached further into wildlife habitats, the risk of EIDs of zoonotic origin has increased (Dazak et al., 2000). This human encroachment may be responsible for the increase in the incidence of such zoonoses as Hantavirus, Nipah virus and Lyme disease in human populations (Dazak and Cunningham, 2002). On the other hand, humans and domestic animals have been identified as major contributors of disease and infection in primates (Nunn and Altizer, 2006).

Also key to conservation medicine are enzootic diseases endemic to wildlife populations. Wildlife EIDs have been identified on a global scale and include factors such as host-switching parasitic organisms, disease transmission into previously naive populations, and the combination of these two factors. These wildlife EIDs are especially dangerous to endangered wildlife with small fragmented populations (Dazak and Cunningham, 2002).